Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1 | /* |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2 | * Generic process-grouping system. |
| 3 | * |
| 4 | * Based originally on the cpuset system, extracted by Paul Menage |
| 5 | * Copyright (C) 2006 Google, Inc |
| 6 | * |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 7 | * Notifications support |
| 8 | * Copyright (C) 2009 Nokia Corporation |
| 9 | * Author: Kirill A. Shutemov |
| 10 | * |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 11 | * Copyright notices from the original cpuset code: |
| 12 | * -------------------------------------------------- |
| 13 | * Copyright (C) 2003 BULL SA. |
| 14 | * Copyright (C) 2004-2006 Silicon Graphics, Inc. |
| 15 | * |
| 16 | * Portions derived from Patrick Mochel's sysfs code. |
| 17 | * sysfs is Copyright (c) 2001-3 Patrick Mochel |
| 18 | * |
| 19 | * 2003-10-10 Written by Simon Derr. |
| 20 | * 2003-10-22 Updates by Stephen Hemminger. |
| 21 | * 2004 May-July Rework by Paul Jackson. |
| 22 | * --------------------------------------------------- |
| 23 | * |
| 24 | * This file is subject to the terms and conditions of the GNU General Public |
| 25 | * License. See the file COPYING in the main directory of the Linux |
| 26 | * distribution for more details. |
| 27 | */ |
| 28 | |
| 29 | #include <linux/cgroup.h> |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 30 | #include <linux/ctype.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 31 | #include <linux/errno.h> |
| 32 | #include <linux/fs.h> |
| 33 | #include <linux/kernel.h> |
| 34 | #include <linux/list.h> |
| 35 | #include <linux/mm.h> |
| 36 | #include <linux/mutex.h> |
| 37 | #include <linux/mount.h> |
| 38 | #include <linux/pagemap.h> |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 39 | #include <linux/proc_fs.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 40 | #include <linux/rcupdate.h> |
| 41 | #include <linux/sched.h> |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 42 | #include <linux/backing-dev.h> |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 43 | #include <linux/seq_file.h> |
| 44 | #include <linux/slab.h> |
| 45 | #include <linux/magic.h> |
| 46 | #include <linux/spinlock.h> |
| 47 | #include <linux/string.h> |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 48 | #include <linux/sort.h> |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 49 | #include <linux/kmod.h> |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 50 | #include <linux/module.h> |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 51 | #include <linux/delayacct.h> |
| 52 | #include <linux/cgroupstats.h> |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 53 | #include <linux/hash.h> |
Al Viro | 3f8206d | 2008-07-26 03:46:43 -0400 | [diff] [blame] | 54 | #include <linux/namei.h> |
Li Zefan | 096b7fe | 2009-07-29 15:04:04 -0700 | [diff] [blame] | 55 | #include <linux/pid_namespace.h> |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 56 | #include <linux/idr.h> |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 57 | #include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */ |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 58 | #include <linux/eventfd.h> |
| 59 | #include <linux/poll.h> |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 60 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 61 | #include <asm/atomic.h> |
| 62 | |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 63 | static DEFINE_MUTEX(cgroup_mutex); |
| 64 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 65 | /* |
| 66 | * Generate an array of cgroup subsystem pointers. At boot time, this is |
| 67 | * populated up to CGROUP_BUILTIN_SUBSYS_COUNT, and modular subsystems are |
| 68 | * registered after that. The mutable section of this array is protected by |
| 69 | * cgroup_mutex. |
| 70 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 71 | #define SUBSYS(_x) &_x ## _subsys, |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 72 | static struct cgroup_subsys *subsys[CGROUP_SUBSYS_COUNT] = { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 73 | #include <linux/cgroup_subsys.h> |
| 74 | }; |
| 75 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 76 | #define MAX_CGROUP_ROOT_NAMELEN 64 |
| 77 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 78 | /* |
| 79 | * A cgroupfs_root represents the root of a cgroup hierarchy, |
| 80 | * and may be associated with a superblock to form an active |
| 81 | * hierarchy |
| 82 | */ |
| 83 | struct cgroupfs_root { |
| 84 | struct super_block *sb; |
| 85 | |
| 86 | /* |
| 87 | * The bitmask of subsystems intended to be attached to this |
| 88 | * hierarchy |
| 89 | */ |
| 90 | unsigned long subsys_bits; |
| 91 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 92 | /* Unique id for this hierarchy. */ |
| 93 | int hierarchy_id; |
| 94 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 95 | /* The bitmask of subsystems currently attached to this hierarchy */ |
| 96 | unsigned long actual_subsys_bits; |
| 97 | |
| 98 | /* A list running through the attached subsystems */ |
| 99 | struct list_head subsys_list; |
| 100 | |
| 101 | /* The root cgroup for this hierarchy */ |
| 102 | struct cgroup top_cgroup; |
| 103 | |
| 104 | /* Tracks how many cgroups are currently defined in hierarchy.*/ |
| 105 | int number_of_cgroups; |
| 106 | |
Li Zefan | e5f6a86 | 2009-01-07 18:07:41 -0800 | [diff] [blame] | 107 | /* A list running through the active hierarchies */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 108 | struct list_head root_list; |
| 109 | |
| 110 | /* Hierarchy-specific flags */ |
| 111 | unsigned long flags; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 112 | |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 113 | /* The path to use for release notifications. */ |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 114 | char release_agent_path[PATH_MAX]; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 115 | |
| 116 | /* The name for this hierarchy - may be empty */ |
| 117 | char name[MAX_CGROUP_ROOT_NAMELEN]; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 118 | }; |
| 119 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 120 | /* |
| 121 | * The "rootnode" hierarchy is the "dummy hierarchy", reserved for the |
| 122 | * subsystems that are otherwise unattached - it never has more than a |
| 123 | * single cgroup, and all tasks are part of that cgroup. |
| 124 | */ |
| 125 | static struct cgroupfs_root rootnode; |
| 126 | |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 127 | /* |
| 128 | * CSS ID -- ID per subsys's Cgroup Subsys State(CSS). used only when |
| 129 | * cgroup_subsys->use_id != 0. |
| 130 | */ |
| 131 | #define CSS_ID_MAX (65535) |
| 132 | struct css_id { |
| 133 | /* |
| 134 | * The css to which this ID points. This pointer is set to valid value |
| 135 | * after cgroup is populated. If cgroup is removed, this will be NULL. |
| 136 | * This pointer is expected to be RCU-safe because destroy() |
| 137 | * is called after synchronize_rcu(). But for safe use, css_is_removed() |
| 138 | * css_tryget() should be used for avoiding race. |
| 139 | */ |
Arnd Bergmann | 2c392b8 | 2010-02-24 19:41:39 +0100 | [diff] [blame] | 140 | struct cgroup_subsys_state __rcu *css; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 141 | /* |
| 142 | * ID of this css. |
| 143 | */ |
| 144 | unsigned short id; |
| 145 | /* |
| 146 | * Depth in hierarchy which this ID belongs to. |
| 147 | */ |
| 148 | unsigned short depth; |
| 149 | /* |
| 150 | * ID is freed by RCU. (and lookup routine is RCU safe.) |
| 151 | */ |
| 152 | struct rcu_head rcu_head; |
| 153 | /* |
| 154 | * Hierarchy of CSS ID belongs to. |
| 155 | */ |
| 156 | unsigned short stack[0]; /* Array of Length (depth+1) */ |
| 157 | }; |
| 158 | |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 159 | /* |
| 160 | * cgroup_event represents events which userspace want to recieve. |
| 161 | */ |
| 162 | struct cgroup_event { |
| 163 | /* |
| 164 | * Cgroup which the event belongs to. |
| 165 | */ |
| 166 | struct cgroup *cgrp; |
| 167 | /* |
| 168 | * Control file which the event associated. |
| 169 | */ |
| 170 | struct cftype *cft; |
| 171 | /* |
| 172 | * eventfd to signal userspace about the event. |
| 173 | */ |
| 174 | struct eventfd_ctx *eventfd; |
| 175 | /* |
| 176 | * Each of these stored in a list by the cgroup. |
| 177 | */ |
| 178 | struct list_head list; |
| 179 | /* |
| 180 | * All fields below needed to unregister event when |
| 181 | * userspace closes eventfd. |
| 182 | */ |
| 183 | poll_table pt; |
| 184 | wait_queue_head_t *wqh; |
| 185 | wait_queue_t wait; |
| 186 | struct work_struct remove; |
| 187 | }; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 188 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 189 | /* The list of hierarchy roots */ |
| 190 | |
| 191 | static LIST_HEAD(roots); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 192 | static int root_count; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 193 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 194 | static DEFINE_IDA(hierarchy_ida); |
| 195 | static int next_hierarchy_id; |
| 196 | static DEFINE_SPINLOCK(hierarchy_id_lock); |
| 197 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 198 | /* dummytop is a shorthand for the dummy hierarchy's top cgroup */ |
| 199 | #define dummytop (&rootnode.top_cgroup) |
| 200 | |
| 201 | /* This flag indicates whether tasks in the fork and exit paths should |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 202 | * check for fork/exit handlers to call. This avoids us having to do |
| 203 | * extra work in the fork/exit path if none of the subsystems need to |
| 204 | * be called. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 205 | */ |
Li Zefan | 8947f9d | 2008-07-25 01:46:56 -0700 | [diff] [blame] | 206 | static int need_forkexit_callback __read_mostly; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 207 | |
Paul E. McKenney | d11c563 | 2010-02-22 17:04:50 -0800 | [diff] [blame] | 208 | #ifdef CONFIG_PROVE_LOCKING |
| 209 | int cgroup_lock_is_held(void) |
| 210 | { |
| 211 | return lockdep_is_held(&cgroup_mutex); |
| 212 | } |
| 213 | #else /* #ifdef CONFIG_PROVE_LOCKING */ |
| 214 | int cgroup_lock_is_held(void) |
| 215 | { |
| 216 | return mutex_is_locked(&cgroup_mutex); |
| 217 | } |
| 218 | #endif /* #else #ifdef CONFIG_PROVE_LOCKING */ |
| 219 | |
| 220 | EXPORT_SYMBOL_GPL(cgroup_lock_is_held); |
| 221 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 222 | /* convenient tests for these bits */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 223 | inline int cgroup_is_removed(const struct cgroup *cgrp) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 224 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 225 | return test_bit(CGRP_REMOVED, &cgrp->flags); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 226 | } |
| 227 | |
| 228 | /* bits in struct cgroupfs_root flags field */ |
| 229 | enum { |
| 230 | ROOT_NOPREFIX, /* mounted subsystems have no named prefix */ |
| 231 | }; |
| 232 | |
Adrian Bunk | e9685a0 | 2008-02-07 00:13:46 -0800 | [diff] [blame] | 233 | static int cgroup_is_releasable(const struct cgroup *cgrp) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 234 | { |
| 235 | const int bits = |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 236 | (1 << CGRP_RELEASABLE) | |
| 237 | (1 << CGRP_NOTIFY_ON_RELEASE); |
| 238 | return (cgrp->flags & bits) == bits; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 239 | } |
| 240 | |
Adrian Bunk | e9685a0 | 2008-02-07 00:13:46 -0800 | [diff] [blame] | 241 | static int notify_on_release(const struct cgroup *cgrp) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 242 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 243 | return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 244 | } |
| 245 | |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 246 | static int clone_children(const struct cgroup *cgrp) |
| 247 | { |
| 248 | return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); |
| 249 | } |
| 250 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 251 | /* |
| 252 | * for_each_subsys() allows you to iterate on each subsystem attached to |
| 253 | * an active hierarchy |
| 254 | */ |
| 255 | #define for_each_subsys(_root, _ss) \ |
| 256 | list_for_each_entry(_ss, &_root->subsys_list, sibling) |
| 257 | |
Li Zefan | e5f6a86 | 2009-01-07 18:07:41 -0800 | [diff] [blame] | 258 | /* for_each_active_root() allows you to iterate across the active hierarchies */ |
| 259 | #define for_each_active_root(_root) \ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 260 | list_for_each_entry(_root, &roots, root_list) |
| 261 | |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 262 | /* the list of cgroups eligible for automatic release. Protected by |
| 263 | * release_list_lock */ |
| 264 | static LIST_HEAD(release_list); |
| 265 | static DEFINE_SPINLOCK(release_list_lock); |
| 266 | static void cgroup_release_agent(struct work_struct *work); |
| 267 | static DECLARE_WORK(release_agent_work, cgroup_release_agent); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 268 | static void check_for_release(struct cgroup *cgrp); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 269 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 270 | /* Link structure for associating css_set objects with cgroups */ |
| 271 | struct cg_cgroup_link { |
| 272 | /* |
| 273 | * List running through cg_cgroup_links associated with a |
| 274 | * cgroup, anchored on cgroup->css_sets |
| 275 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 276 | struct list_head cgrp_link_list; |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 277 | struct cgroup *cgrp; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 278 | /* |
| 279 | * List running through cg_cgroup_links pointing at a |
| 280 | * single css_set object, anchored on css_set->cg_links |
| 281 | */ |
| 282 | struct list_head cg_link_list; |
| 283 | struct css_set *cg; |
| 284 | }; |
| 285 | |
| 286 | /* The default css_set - used by init and its children prior to any |
| 287 | * hierarchies being mounted. It contains a pointer to the root state |
| 288 | * for each subsystem. Also used to anchor the list of css_sets. Not |
| 289 | * reference-counted, to improve performance when child cgroups |
| 290 | * haven't been created. |
| 291 | */ |
| 292 | |
| 293 | static struct css_set init_css_set; |
| 294 | static struct cg_cgroup_link init_css_set_link; |
| 295 | |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 296 | static int cgroup_init_idr(struct cgroup_subsys *ss, |
| 297 | struct cgroup_subsys_state *css); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 298 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 299 | /* css_set_lock protects the list of css_set objects, and the |
| 300 | * chain of tasks off each css_set. Nests outside task->alloc_lock |
| 301 | * due to cgroup_iter_start() */ |
| 302 | static DEFINE_RWLOCK(css_set_lock); |
| 303 | static int css_set_count; |
| 304 | |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 305 | /* |
| 306 | * hash table for cgroup groups. This improves the performance to find |
| 307 | * an existing css_set. This hash doesn't (currently) take into |
| 308 | * account cgroups in empty hierarchies. |
| 309 | */ |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 310 | #define CSS_SET_HASH_BITS 7 |
| 311 | #define CSS_SET_TABLE_SIZE (1 << CSS_SET_HASH_BITS) |
| 312 | static struct hlist_head css_set_table[CSS_SET_TABLE_SIZE]; |
| 313 | |
| 314 | static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[]) |
| 315 | { |
| 316 | int i; |
| 317 | int index; |
| 318 | unsigned long tmp = 0UL; |
| 319 | |
| 320 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) |
| 321 | tmp += (unsigned long)css[i]; |
| 322 | tmp = (tmp >> 16) ^ tmp; |
| 323 | |
| 324 | index = hash_long(tmp, CSS_SET_HASH_BITS); |
| 325 | |
| 326 | return &css_set_table[index]; |
| 327 | } |
| 328 | |
Ben Blum | c378369 | 2009-09-23 15:56:29 -0700 | [diff] [blame] | 329 | static void free_css_set_rcu(struct rcu_head *obj) |
| 330 | { |
| 331 | struct css_set *cg = container_of(obj, struct css_set, rcu_head); |
| 332 | kfree(cg); |
| 333 | } |
| 334 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 335 | /* We don't maintain the lists running through each css_set to its |
| 336 | * task until after the first call to cgroup_iter_start(). This |
| 337 | * reduces the fork()/exit() overhead for people who have cgroups |
| 338 | * compiled into their kernel but not actually in use */ |
Li Zefan | 8947f9d | 2008-07-25 01:46:56 -0700 | [diff] [blame] | 339 | static int use_task_css_set_links __read_mostly; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 340 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 341 | static void __put_css_set(struct css_set *cg, int taskexit) |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 342 | { |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 343 | struct cg_cgroup_link *link; |
| 344 | struct cg_cgroup_link *saved_link; |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 345 | /* |
| 346 | * Ensure that the refcount doesn't hit zero while any readers |
| 347 | * can see it. Similar to atomic_dec_and_lock(), but for an |
| 348 | * rwlock |
| 349 | */ |
| 350 | if (atomic_add_unless(&cg->refcount, -1, 1)) |
| 351 | return; |
| 352 | write_lock(&css_set_lock); |
| 353 | if (!atomic_dec_and_test(&cg->refcount)) { |
| 354 | write_unlock(&css_set_lock); |
| 355 | return; |
| 356 | } |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 357 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 358 | /* This css_set is dead. unlink it and release cgroup refcounts */ |
| 359 | hlist_del(&cg->hlist); |
| 360 | css_set_count--; |
| 361 | |
| 362 | list_for_each_entry_safe(link, saved_link, &cg->cg_links, |
| 363 | cg_link_list) { |
| 364 | struct cgroup *cgrp = link->cgrp; |
| 365 | list_del(&link->cg_link_list); |
| 366 | list_del(&link->cgrp_link_list); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 367 | if (atomic_dec_and_test(&cgrp->count) && |
| 368 | notify_on_release(cgrp)) { |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 369 | if (taskexit) |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 370 | set_bit(CGRP_RELEASABLE, &cgrp->flags); |
| 371 | check_for_release(cgrp); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 372 | } |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 373 | |
| 374 | kfree(link); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 375 | } |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 376 | |
| 377 | write_unlock(&css_set_lock); |
Ben Blum | c378369 | 2009-09-23 15:56:29 -0700 | [diff] [blame] | 378 | call_rcu(&cg->rcu_head, free_css_set_rcu); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 379 | } |
| 380 | |
| 381 | /* |
| 382 | * refcounted get/put for css_set objects |
| 383 | */ |
| 384 | static inline void get_css_set(struct css_set *cg) |
| 385 | { |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 386 | atomic_inc(&cg->refcount); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 387 | } |
| 388 | |
| 389 | static inline void put_css_set(struct css_set *cg) |
| 390 | { |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 391 | __put_css_set(cg, 0); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 392 | } |
| 393 | |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 394 | static inline void put_css_set_taskexit(struct css_set *cg) |
| 395 | { |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 396 | __put_css_set(cg, 1); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 397 | } |
| 398 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 399 | /* |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 400 | * compare_css_sets - helper function for find_existing_css_set(). |
| 401 | * @cg: candidate css_set being tested |
| 402 | * @old_cg: existing css_set for a task |
| 403 | * @new_cgrp: cgroup that's being entered by the task |
| 404 | * @template: desired set of css pointers in css_set (pre-calculated) |
| 405 | * |
| 406 | * Returns true if "cg" matches "old_cg" except for the hierarchy |
| 407 | * which "new_cgrp" belongs to, for which it should match "new_cgrp". |
| 408 | */ |
| 409 | static bool compare_css_sets(struct css_set *cg, |
| 410 | struct css_set *old_cg, |
| 411 | struct cgroup *new_cgrp, |
| 412 | struct cgroup_subsys_state *template[]) |
| 413 | { |
| 414 | struct list_head *l1, *l2; |
| 415 | |
| 416 | if (memcmp(template, cg->subsys, sizeof(cg->subsys))) { |
| 417 | /* Not all subsystems matched */ |
| 418 | return false; |
| 419 | } |
| 420 | |
| 421 | /* |
| 422 | * Compare cgroup pointers in order to distinguish between |
| 423 | * different cgroups in heirarchies with no subsystems. We |
| 424 | * could get by with just this check alone (and skip the |
| 425 | * memcmp above) but on most setups the memcmp check will |
| 426 | * avoid the need for this more expensive check on almost all |
| 427 | * candidates. |
| 428 | */ |
| 429 | |
| 430 | l1 = &cg->cg_links; |
| 431 | l2 = &old_cg->cg_links; |
| 432 | while (1) { |
| 433 | struct cg_cgroup_link *cgl1, *cgl2; |
| 434 | struct cgroup *cg1, *cg2; |
| 435 | |
| 436 | l1 = l1->next; |
| 437 | l2 = l2->next; |
| 438 | /* See if we reached the end - both lists are equal length. */ |
| 439 | if (l1 == &cg->cg_links) { |
| 440 | BUG_ON(l2 != &old_cg->cg_links); |
| 441 | break; |
| 442 | } else { |
| 443 | BUG_ON(l2 == &old_cg->cg_links); |
| 444 | } |
| 445 | /* Locate the cgroups associated with these links. */ |
| 446 | cgl1 = list_entry(l1, struct cg_cgroup_link, cg_link_list); |
| 447 | cgl2 = list_entry(l2, struct cg_cgroup_link, cg_link_list); |
| 448 | cg1 = cgl1->cgrp; |
| 449 | cg2 = cgl2->cgrp; |
| 450 | /* Hierarchies should be linked in the same order. */ |
| 451 | BUG_ON(cg1->root != cg2->root); |
| 452 | |
| 453 | /* |
| 454 | * If this hierarchy is the hierarchy of the cgroup |
| 455 | * that's changing, then we need to check that this |
| 456 | * css_set points to the new cgroup; if it's any other |
| 457 | * hierarchy, then this css_set should point to the |
| 458 | * same cgroup as the old css_set. |
| 459 | */ |
| 460 | if (cg1->root == new_cgrp->root) { |
| 461 | if (cg1 != new_cgrp) |
| 462 | return false; |
| 463 | } else { |
| 464 | if (cg1 != cg2) |
| 465 | return false; |
| 466 | } |
| 467 | } |
| 468 | return true; |
| 469 | } |
| 470 | |
| 471 | /* |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 472 | * find_existing_css_set() is a helper for |
| 473 | * find_css_set(), and checks to see whether an existing |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 474 | * css_set is suitable. |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 475 | * |
| 476 | * oldcg: the cgroup group that we're using before the cgroup |
| 477 | * transition |
| 478 | * |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 479 | * cgrp: the cgroup that we're moving into |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 480 | * |
| 481 | * template: location in which to build the desired set of subsystem |
| 482 | * state objects for the new cgroup group |
| 483 | */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 484 | static struct css_set *find_existing_css_set( |
| 485 | struct css_set *oldcg, |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 486 | struct cgroup *cgrp, |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 487 | struct cgroup_subsys_state *template[]) |
| 488 | { |
| 489 | int i; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 490 | struct cgroupfs_root *root = cgrp->root; |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 491 | struct hlist_head *hhead; |
| 492 | struct hlist_node *node; |
| 493 | struct css_set *cg; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 494 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 495 | /* |
| 496 | * Build the set of subsystem state objects that we want to see in the |
| 497 | * new css_set. while subsystems can change globally, the entries here |
| 498 | * won't change, so no need for locking. |
| 499 | */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 500 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
Li Zefan | 8d53d55 | 2008-02-23 15:24:11 -0800 | [diff] [blame] | 501 | if (root->subsys_bits & (1UL << i)) { |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 502 | /* Subsystem is in this hierarchy. So we want |
| 503 | * the subsystem state from the new |
| 504 | * cgroup */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 505 | template[i] = cgrp->subsys[i]; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 506 | } else { |
| 507 | /* Subsystem is not in this hierarchy, so we |
| 508 | * don't want to change the subsystem state */ |
| 509 | template[i] = oldcg->subsys[i]; |
| 510 | } |
| 511 | } |
| 512 | |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 513 | hhead = css_set_hash(template); |
| 514 | hlist_for_each_entry(cg, node, hhead, hlist) { |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 515 | if (!compare_css_sets(cg, oldcg, cgrp, template)) |
| 516 | continue; |
| 517 | |
| 518 | /* This css_set matches what we need */ |
| 519 | return cg; |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 520 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 521 | |
| 522 | /* No existing cgroup group matched */ |
| 523 | return NULL; |
| 524 | } |
| 525 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 526 | static void free_cg_links(struct list_head *tmp) |
| 527 | { |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 528 | struct cg_cgroup_link *link; |
| 529 | struct cg_cgroup_link *saved_link; |
| 530 | |
| 531 | list_for_each_entry_safe(link, saved_link, tmp, cgrp_link_list) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 532 | list_del(&link->cgrp_link_list); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 533 | kfree(link); |
| 534 | } |
| 535 | } |
| 536 | |
| 537 | /* |
Li Zefan | 3655343 | 2008-07-29 22:33:19 -0700 | [diff] [blame] | 538 | * allocate_cg_links() allocates "count" cg_cgroup_link structures |
| 539 | * and chains them on tmp through their cgrp_link_list fields. Returns 0 on |
| 540 | * success or a negative error |
| 541 | */ |
| 542 | static int allocate_cg_links(int count, struct list_head *tmp) |
| 543 | { |
| 544 | struct cg_cgroup_link *link; |
| 545 | int i; |
| 546 | INIT_LIST_HEAD(tmp); |
| 547 | for (i = 0; i < count; i++) { |
| 548 | link = kmalloc(sizeof(*link), GFP_KERNEL); |
| 549 | if (!link) { |
| 550 | free_cg_links(tmp); |
| 551 | return -ENOMEM; |
| 552 | } |
| 553 | list_add(&link->cgrp_link_list, tmp); |
| 554 | } |
| 555 | return 0; |
| 556 | } |
| 557 | |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 558 | /** |
| 559 | * link_css_set - a helper function to link a css_set to a cgroup |
| 560 | * @tmp_cg_links: cg_cgroup_link objects allocated by allocate_cg_links() |
| 561 | * @cg: the css_set to be linked |
| 562 | * @cgrp: the destination cgroup |
| 563 | */ |
| 564 | static void link_css_set(struct list_head *tmp_cg_links, |
| 565 | struct css_set *cg, struct cgroup *cgrp) |
| 566 | { |
| 567 | struct cg_cgroup_link *link; |
| 568 | |
| 569 | BUG_ON(list_empty(tmp_cg_links)); |
| 570 | link = list_first_entry(tmp_cg_links, struct cg_cgroup_link, |
| 571 | cgrp_link_list); |
| 572 | link->cg = cg; |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 573 | link->cgrp = cgrp; |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 574 | atomic_inc(&cgrp->count); |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 575 | list_move(&link->cgrp_link_list, &cgrp->css_sets); |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 576 | /* |
| 577 | * Always add links to the tail of the list so that the list |
| 578 | * is sorted by order of hierarchy creation |
| 579 | */ |
| 580 | list_add_tail(&link->cg_link_list, &cg->cg_links); |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 581 | } |
| 582 | |
Li Zefan | 3655343 | 2008-07-29 22:33:19 -0700 | [diff] [blame] | 583 | /* |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 584 | * find_css_set() takes an existing cgroup group and a |
| 585 | * cgroup object, and returns a css_set object that's |
| 586 | * equivalent to the old group, but with the given cgroup |
| 587 | * substituted into the appropriate hierarchy. Must be called with |
| 588 | * cgroup_mutex held |
| 589 | */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 590 | static struct css_set *find_css_set( |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 591 | struct css_set *oldcg, struct cgroup *cgrp) |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 592 | { |
| 593 | struct css_set *res; |
| 594 | struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT]; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 595 | |
| 596 | struct list_head tmp_cg_links; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 597 | |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 598 | struct hlist_head *hhead; |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 599 | struct cg_cgroup_link *link; |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 600 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 601 | /* First see if we already have a cgroup group that matches |
| 602 | * the desired set */ |
Li Zefan | 7e9abd8 | 2008-07-25 01:46:54 -0700 | [diff] [blame] | 603 | read_lock(&css_set_lock); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 604 | res = find_existing_css_set(oldcg, cgrp, template); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 605 | if (res) |
| 606 | get_css_set(res); |
Li Zefan | 7e9abd8 | 2008-07-25 01:46:54 -0700 | [diff] [blame] | 607 | read_unlock(&css_set_lock); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 608 | |
| 609 | if (res) |
| 610 | return res; |
| 611 | |
| 612 | res = kmalloc(sizeof(*res), GFP_KERNEL); |
| 613 | if (!res) |
| 614 | return NULL; |
| 615 | |
| 616 | /* Allocate all the cg_cgroup_link objects that we'll need */ |
| 617 | if (allocate_cg_links(root_count, &tmp_cg_links) < 0) { |
| 618 | kfree(res); |
| 619 | return NULL; |
| 620 | } |
| 621 | |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 622 | atomic_set(&res->refcount, 1); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 623 | INIT_LIST_HEAD(&res->cg_links); |
| 624 | INIT_LIST_HEAD(&res->tasks); |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 625 | INIT_HLIST_NODE(&res->hlist); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 626 | |
| 627 | /* Copy the set of subsystem state objects generated in |
| 628 | * find_existing_css_set() */ |
| 629 | memcpy(res->subsys, template, sizeof(res->subsys)); |
| 630 | |
| 631 | write_lock(&css_set_lock); |
| 632 | /* Add reference counts and links from the new css_set. */ |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 633 | list_for_each_entry(link, &oldcg->cg_links, cg_link_list) { |
| 634 | struct cgroup *c = link->cgrp; |
| 635 | if (c->root == cgrp->root) |
| 636 | c = cgrp; |
| 637 | link_css_set(&tmp_cg_links, res, c); |
| 638 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 639 | |
| 640 | BUG_ON(!list_empty(&tmp_cg_links)); |
| 641 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 642 | css_set_count++; |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 643 | |
| 644 | /* Add this cgroup group to the hash table */ |
| 645 | hhead = css_set_hash(res->subsys); |
| 646 | hlist_add_head(&res->hlist, hhead); |
| 647 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 648 | write_unlock(&css_set_lock); |
| 649 | |
| 650 | return res; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 651 | } |
| 652 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 653 | /* |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 654 | * Return the cgroup for "task" from the given hierarchy. Must be |
| 655 | * called with cgroup_mutex held. |
| 656 | */ |
| 657 | static struct cgroup *task_cgroup_from_root(struct task_struct *task, |
| 658 | struct cgroupfs_root *root) |
| 659 | { |
| 660 | struct css_set *css; |
| 661 | struct cgroup *res = NULL; |
| 662 | |
| 663 | BUG_ON(!mutex_is_locked(&cgroup_mutex)); |
| 664 | read_lock(&css_set_lock); |
| 665 | /* |
| 666 | * No need to lock the task - since we hold cgroup_mutex the |
| 667 | * task can't change groups, so the only thing that can happen |
| 668 | * is that it exits and its css is set back to init_css_set. |
| 669 | */ |
| 670 | css = task->cgroups; |
| 671 | if (css == &init_css_set) { |
| 672 | res = &root->top_cgroup; |
| 673 | } else { |
| 674 | struct cg_cgroup_link *link; |
| 675 | list_for_each_entry(link, &css->cg_links, cg_link_list) { |
| 676 | struct cgroup *c = link->cgrp; |
| 677 | if (c->root == root) { |
| 678 | res = c; |
| 679 | break; |
| 680 | } |
| 681 | } |
| 682 | } |
| 683 | read_unlock(&css_set_lock); |
| 684 | BUG_ON(!res); |
| 685 | return res; |
| 686 | } |
| 687 | |
| 688 | /* |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 689 | * There is one global cgroup mutex. We also require taking |
| 690 | * task_lock() when dereferencing a task's cgroup subsys pointers. |
| 691 | * See "The task_lock() exception", at the end of this comment. |
| 692 | * |
| 693 | * A task must hold cgroup_mutex to modify cgroups. |
| 694 | * |
| 695 | * Any task can increment and decrement the count field without lock. |
| 696 | * So in general, code holding cgroup_mutex can't rely on the count |
| 697 | * field not changing. However, if the count goes to zero, then only |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 698 | * cgroup_attach_task() can increment it again. Because a count of zero |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 699 | * means that no tasks are currently attached, therefore there is no |
| 700 | * way a task attached to that cgroup can fork (the other way to |
| 701 | * increment the count). So code holding cgroup_mutex can safely |
| 702 | * assume that if the count is zero, it will stay zero. Similarly, if |
| 703 | * a task holds cgroup_mutex on a cgroup with zero count, it |
| 704 | * knows that the cgroup won't be removed, as cgroup_rmdir() |
| 705 | * needs that mutex. |
| 706 | * |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 707 | * The fork and exit callbacks cgroup_fork() and cgroup_exit(), don't |
| 708 | * (usually) take cgroup_mutex. These are the two most performance |
| 709 | * critical pieces of code here. The exception occurs on cgroup_exit(), |
| 710 | * when a task in a notify_on_release cgroup exits. Then cgroup_mutex |
| 711 | * is taken, and if the cgroup count is zero, a usermode call made |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 712 | * to the release agent with the name of the cgroup (path relative to |
| 713 | * the root of cgroup file system) as the argument. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 714 | * |
| 715 | * A cgroup can only be deleted if both its 'count' of using tasks |
| 716 | * is zero, and its list of 'children' cgroups is empty. Since all |
| 717 | * tasks in the system use _some_ cgroup, and since there is always at |
| 718 | * least one task in the system (init, pid == 1), therefore, top_cgroup |
| 719 | * always has either children cgroups and/or using tasks. So we don't |
| 720 | * need a special hack to ensure that top_cgroup cannot be deleted. |
| 721 | * |
| 722 | * The task_lock() exception |
| 723 | * |
| 724 | * The need for this exception arises from the action of |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 725 | * cgroup_attach_task(), which overwrites one tasks cgroup pointer with |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 726 | * another. It does so using cgroup_mutex, however there are |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 727 | * several performance critical places that need to reference |
| 728 | * task->cgroup without the expense of grabbing a system global |
| 729 | * mutex. Therefore except as noted below, when dereferencing or, as |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 730 | * in cgroup_attach_task(), modifying a task'ss cgroup pointer we use |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 731 | * task_lock(), which acts on a spinlock (task->alloc_lock) already in |
| 732 | * the task_struct routinely used for such matters. |
| 733 | * |
| 734 | * P.S. One more locking exception. RCU is used to guard the |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 735 | * update of a tasks cgroup pointer by cgroup_attach_task() |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 736 | */ |
| 737 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 738 | /** |
| 739 | * cgroup_lock - lock out any changes to cgroup structures |
| 740 | * |
| 741 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 742 | void cgroup_lock(void) |
| 743 | { |
| 744 | mutex_lock(&cgroup_mutex); |
| 745 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 746 | EXPORT_SYMBOL_GPL(cgroup_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 747 | |
| 748 | /** |
| 749 | * cgroup_unlock - release lock on cgroup changes |
| 750 | * |
| 751 | * Undo the lock taken in a previous cgroup_lock() call. |
| 752 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 753 | void cgroup_unlock(void) |
| 754 | { |
| 755 | mutex_unlock(&cgroup_mutex); |
| 756 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 757 | EXPORT_SYMBOL_GPL(cgroup_unlock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 758 | |
| 759 | /* |
| 760 | * A couple of forward declarations required, due to cyclic reference loop: |
| 761 | * cgroup_mkdir -> cgroup_create -> cgroup_populate_dir -> |
| 762 | * cgroup_add_file -> cgroup_create_file -> cgroup_dir_inode_operations |
| 763 | * -> cgroup_mkdir. |
| 764 | */ |
| 765 | |
| 766 | static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode); |
Al Viro | c72a04e | 2011-01-14 05:31:45 +0000 | [diff] [blame] | 767 | static struct dentry *cgroup_lookup(struct inode *, struct dentry *, struct nameidata *); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 768 | static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 769 | static int cgroup_populate_dir(struct cgroup *cgrp); |
Alexey Dobriyan | 6e1d5dc | 2009-09-21 17:01:11 -0700 | [diff] [blame] | 770 | static const struct inode_operations cgroup_dir_inode_operations; |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 771 | static const struct file_operations proc_cgroupstats_operations; |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 772 | |
| 773 | static struct backing_dev_info cgroup_backing_dev_info = { |
Jens Axboe | d993831 | 2009-06-12 14:45:52 +0200 | [diff] [blame] | 774 | .name = "cgroup", |
Miklos Szeredi | e4ad08f | 2008-04-30 00:54:37 -0700 | [diff] [blame] | 775 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 776 | }; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 777 | |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 778 | static int alloc_css_id(struct cgroup_subsys *ss, |
| 779 | struct cgroup *parent, struct cgroup *child); |
| 780 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 781 | static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) |
| 782 | { |
| 783 | struct inode *inode = new_inode(sb); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 784 | |
| 785 | if (inode) { |
Christoph Hellwig | 85fe402 | 2010-10-23 11:19:54 -0400 | [diff] [blame] | 786 | inode->i_ino = get_next_ino(); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 787 | inode->i_mode = mode; |
David Howells | 76aac0e | 2008-11-14 10:39:12 +1100 | [diff] [blame] | 788 | inode->i_uid = current_fsuid(); |
| 789 | inode->i_gid = current_fsgid(); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 790 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 791 | inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info; |
| 792 | } |
| 793 | return inode; |
| 794 | } |
| 795 | |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 796 | /* |
| 797 | * Call subsys's pre_destroy handler. |
| 798 | * This is called before css refcnt check. |
| 799 | */ |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 800 | static int cgroup_call_pre_destroy(struct cgroup *cgrp) |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 801 | { |
| 802 | struct cgroup_subsys *ss; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 803 | int ret = 0; |
| 804 | |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 805 | for_each_subsys(cgrp->root, ss) |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 806 | if (ss->pre_destroy) { |
| 807 | ret = ss->pre_destroy(ss, cgrp); |
| 808 | if (ret) |
Kirill A. Shutemov | 4ab7868 | 2010-03-10 15:22:34 -0800 | [diff] [blame] | 809 | break; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 810 | } |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 811 | |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 812 | return ret; |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 813 | } |
| 814 | |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 815 | static void free_cgroup_rcu(struct rcu_head *obj) |
| 816 | { |
| 817 | struct cgroup *cgrp = container_of(obj, struct cgroup, rcu_head); |
| 818 | |
| 819 | kfree(cgrp); |
| 820 | } |
| 821 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 822 | static void cgroup_diput(struct dentry *dentry, struct inode *inode) |
| 823 | { |
| 824 | /* is dentry a directory ? if so, kfree() associated cgroup */ |
| 825 | if (S_ISDIR(inode->i_mode)) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 826 | struct cgroup *cgrp = dentry->d_fsdata; |
Paul Menage | 8dc4f3e | 2008-02-07 00:13:45 -0800 | [diff] [blame] | 827 | struct cgroup_subsys *ss; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 828 | BUG_ON(!(cgroup_is_removed(cgrp))); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 829 | /* It's possible for external users to be holding css |
| 830 | * reference counts on a cgroup; css_put() needs to |
| 831 | * be able to access the cgroup after decrementing |
| 832 | * the reference count in order to know if it needs to |
| 833 | * queue the cgroup to be handled by the release |
| 834 | * agent */ |
| 835 | synchronize_rcu(); |
Paul Menage | 8dc4f3e | 2008-02-07 00:13:45 -0800 | [diff] [blame] | 836 | |
| 837 | mutex_lock(&cgroup_mutex); |
| 838 | /* |
| 839 | * Release the subsystem state objects. |
| 840 | */ |
Li Zefan | 75139b8 | 2009-01-07 18:07:33 -0800 | [diff] [blame] | 841 | for_each_subsys(cgrp->root, ss) |
| 842 | ss->destroy(ss, cgrp); |
Paul Menage | 8dc4f3e | 2008-02-07 00:13:45 -0800 | [diff] [blame] | 843 | |
| 844 | cgrp->root->number_of_cgroups--; |
| 845 | mutex_unlock(&cgroup_mutex); |
| 846 | |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 847 | /* |
| 848 | * Drop the active superblock reference that we took when we |
| 849 | * created the cgroup |
| 850 | */ |
Paul Menage | 8dc4f3e | 2008-02-07 00:13:45 -0800 | [diff] [blame] | 851 | deactivate_super(cgrp->root->sb); |
| 852 | |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 853 | /* |
| 854 | * if we're getting rid of the cgroup, refcount should ensure |
| 855 | * that there are no pidlists left. |
| 856 | */ |
| 857 | BUG_ON(!list_empty(&cgrp->pidlists)); |
| 858 | |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 859 | call_rcu(&cgrp->rcu_head, free_cgroup_rcu); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 860 | } |
| 861 | iput(inode); |
| 862 | } |
| 863 | |
Al Viro | c72a04e | 2011-01-14 05:31:45 +0000 | [diff] [blame] | 864 | static int cgroup_delete(const struct dentry *d) |
| 865 | { |
| 866 | return 1; |
| 867 | } |
| 868 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 869 | static void remove_dir(struct dentry *d) |
| 870 | { |
| 871 | struct dentry *parent = dget(d->d_parent); |
| 872 | |
| 873 | d_delete(d); |
| 874 | simple_rmdir(parent->d_inode, d); |
| 875 | dput(parent); |
| 876 | } |
| 877 | |
| 878 | static void cgroup_clear_directory(struct dentry *dentry) |
| 879 | { |
| 880 | struct list_head *node; |
| 881 | |
| 882 | BUG_ON(!mutex_is_locked(&dentry->d_inode->i_mutex)); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 883 | spin_lock(&dentry->d_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 884 | node = dentry->d_subdirs.next; |
| 885 | while (node != &dentry->d_subdirs) { |
| 886 | struct dentry *d = list_entry(node, struct dentry, d_u.d_child); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 887 | |
| 888 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 889 | list_del_init(node); |
| 890 | if (d->d_inode) { |
| 891 | /* This should never be called on a cgroup |
| 892 | * directory with child cgroups */ |
| 893 | BUG_ON(d->d_inode->i_mode & S_IFDIR); |
Nick Piggin | dc0474b | 2011-01-07 17:49:43 +1100 | [diff] [blame] | 894 | dget_dlock(d); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 895 | spin_unlock(&d->d_lock); |
| 896 | spin_unlock(&dentry->d_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 897 | d_delete(d); |
| 898 | simple_unlink(dentry->d_inode, d); |
| 899 | dput(d); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 900 | spin_lock(&dentry->d_lock); |
| 901 | } else |
| 902 | spin_unlock(&d->d_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 903 | node = dentry->d_subdirs.next; |
| 904 | } |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 905 | spin_unlock(&dentry->d_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 906 | } |
| 907 | |
| 908 | /* |
| 909 | * NOTE : the dentry must have been dget()'ed |
| 910 | */ |
| 911 | static void cgroup_d_remove_dir(struct dentry *dentry) |
| 912 | { |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 913 | struct dentry *parent; |
| 914 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 915 | cgroup_clear_directory(dentry); |
| 916 | |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 917 | parent = dentry->d_parent; |
| 918 | spin_lock(&parent->d_lock); |
Li Zefan | 3ec762a | 2011-01-14 11:34:34 +0800 | [diff] [blame] | 919 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 920 | list_del_init(&dentry->d_u.d_child); |
Nick Piggin | 2fd6b7f | 2011-01-07 17:49:34 +1100 | [diff] [blame] | 921 | spin_unlock(&dentry->d_lock); |
| 922 | spin_unlock(&parent->d_lock); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 923 | remove_dir(dentry); |
| 924 | } |
| 925 | |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 926 | /* |
| 927 | * A queue for waiters to do rmdir() cgroup. A tasks will sleep when |
| 928 | * cgroup->count == 0 && list_empty(&cgroup->children) && subsys has some |
| 929 | * reference to css->refcnt. In general, this refcnt is expected to goes down |
| 930 | * to zero, soon. |
| 931 | * |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 932 | * CGRP_WAIT_ON_RMDIR flag is set under cgroup's inode->i_mutex; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 933 | */ |
| 934 | DECLARE_WAIT_QUEUE_HEAD(cgroup_rmdir_waitq); |
| 935 | |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 936 | static void cgroup_wakeup_rmdir_waiter(struct cgroup *cgrp) |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 937 | { |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 938 | if (unlikely(test_and_clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags))) |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 939 | wake_up_all(&cgroup_rmdir_waitq); |
| 940 | } |
| 941 | |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 942 | void cgroup_exclude_rmdir(struct cgroup_subsys_state *css) |
| 943 | { |
| 944 | css_get(css); |
| 945 | } |
| 946 | |
| 947 | void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css) |
| 948 | { |
| 949 | cgroup_wakeup_rmdir_waiter(css->cgroup); |
| 950 | css_put(css); |
| 951 | } |
| 952 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 953 | /* |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 954 | * Call with cgroup_mutex held. Drops reference counts on modules, including |
| 955 | * any duplicate ones that parse_cgroupfs_options took. If this function |
| 956 | * returns an error, no reference counts are touched. |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 957 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 958 | static int rebind_subsystems(struct cgroupfs_root *root, |
| 959 | unsigned long final_bits) |
| 960 | { |
| 961 | unsigned long added_bits, removed_bits; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 962 | struct cgroup *cgrp = &root->top_cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 963 | int i; |
| 964 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 965 | BUG_ON(!mutex_is_locked(&cgroup_mutex)); |
| 966 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 967 | removed_bits = root->actual_subsys_bits & ~final_bits; |
| 968 | added_bits = final_bits & ~root->actual_subsys_bits; |
| 969 | /* Check that any added subsystems are currently free */ |
| 970 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
Li Zefan | 8d53d55 | 2008-02-23 15:24:11 -0800 | [diff] [blame] | 971 | unsigned long bit = 1UL << i; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 972 | struct cgroup_subsys *ss = subsys[i]; |
| 973 | if (!(bit & added_bits)) |
| 974 | continue; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 975 | /* |
| 976 | * Nobody should tell us to do a subsys that doesn't exist: |
| 977 | * parse_cgroupfs_options should catch that case and refcounts |
| 978 | * ensure that subsystems won't disappear once selected. |
| 979 | */ |
| 980 | BUG_ON(ss == NULL); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 981 | if (ss->root != &rootnode) { |
| 982 | /* Subsystem isn't free */ |
| 983 | return -EBUSY; |
| 984 | } |
| 985 | } |
| 986 | |
| 987 | /* Currently we don't handle adding/removing subsystems when |
| 988 | * any child cgroups exist. This is theoretically supportable |
| 989 | * but involves complex error handling, so it's being left until |
| 990 | * later */ |
Paul Menage | 307257c | 2008-12-15 13:54:22 -0800 | [diff] [blame] | 991 | if (root->number_of_cgroups > 1) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 992 | return -EBUSY; |
| 993 | |
| 994 | /* Process each subsystem */ |
| 995 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 996 | struct cgroup_subsys *ss = subsys[i]; |
| 997 | unsigned long bit = 1UL << i; |
| 998 | if (bit & added_bits) { |
| 999 | /* We're binding this subsystem to this hierarchy */ |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1000 | BUG_ON(ss == NULL); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1001 | BUG_ON(cgrp->subsys[i]); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1002 | BUG_ON(!dummytop->subsys[i]); |
| 1003 | BUG_ON(dummytop->subsys[i]->cgroup != dummytop); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 1004 | mutex_lock(&ss->hierarchy_mutex); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1005 | cgrp->subsys[i] = dummytop->subsys[i]; |
| 1006 | cgrp->subsys[i]->cgroup = cgrp; |
Li Zefan | 33a68ac | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1007 | list_move(&ss->sibling, &root->subsys_list); |
Lai Jiangshan | b2aa30f | 2009-01-07 18:07:37 -0800 | [diff] [blame] | 1008 | ss->root = root; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1009 | if (ss->bind) |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1010 | ss->bind(ss, cgrp); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 1011 | mutex_unlock(&ss->hierarchy_mutex); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1012 | /* refcount was already taken, and we're keeping it */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1013 | } else if (bit & removed_bits) { |
| 1014 | /* We're removing this subsystem */ |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1015 | BUG_ON(ss == NULL); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1016 | BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]); |
| 1017 | BUG_ON(cgrp->subsys[i]->cgroup != cgrp); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 1018 | mutex_lock(&ss->hierarchy_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1019 | if (ss->bind) |
| 1020 | ss->bind(ss, dummytop); |
| 1021 | dummytop->subsys[i]->cgroup = dummytop; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1022 | cgrp->subsys[i] = NULL; |
Lai Jiangshan | b2aa30f | 2009-01-07 18:07:37 -0800 | [diff] [blame] | 1023 | subsys[i]->root = &rootnode; |
Li Zefan | 33a68ac | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1024 | list_move(&ss->sibling, &rootnode.subsys_list); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 1025 | mutex_unlock(&ss->hierarchy_mutex); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1026 | /* subsystem is now free - drop reference on module */ |
| 1027 | module_put(ss->module); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1028 | } else if (bit & final_bits) { |
| 1029 | /* Subsystem state should already exist */ |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1030 | BUG_ON(ss == NULL); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1031 | BUG_ON(!cgrp->subsys[i]); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1032 | /* |
| 1033 | * a refcount was taken, but we already had one, so |
| 1034 | * drop the extra reference. |
| 1035 | */ |
| 1036 | module_put(ss->module); |
| 1037 | #ifdef CONFIG_MODULE_UNLOAD |
| 1038 | BUG_ON(ss->module && !module_refcount(ss->module)); |
| 1039 | #endif |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1040 | } else { |
| 1041 | /* Subsystem state shouldn't exist */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1042 | BUG_ON(cgrp->subsys[i]); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1043 | } |
| 1044 | } |
| 1045 | root->subsys_bits = root->actual_subsys_bits = final_bits; |
| 1046 | synchronize_rcu(); |
| 1047 | |
| 1048 | return 0; |
| 1049 | } |
| 1050 | |
| 1051 | static int cgroup_show_options(struct seq_file *seq, struct vfsmount *vfs) |
| 1052 | { |
| 1053 | struct cgroupfs_root *root = vfs->mnt_sb->s_fs_info; |
| 1054 | struct cgroup_subsys *ss; |
| 1055 | |
| 1056 | mutex_lock(&cgroup_mutex); |
| 1057 | for_each_subsys(root, ss) |
| 1058 | seq_printf(seq, ",%s", ss->name); |
| 1059 | if (test_bit(ROOT_NOPREFIX, &root->flags)) |
| 1060 | seq_puts(seq, ",noprefix"); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1061 | if (strlen(root->release_agent_path)) |
| 1062 | seq_printf(seq, ",release_agent=%s", root->release_agent_path); |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 1063 | if (clone_children(&root->top_cgroup)) |
| 1064 | seq_puts(seq, ",clone_children"); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1065 | if (strlen(root->name)) |
| 1066 | seq_printf(seq, ",name=%s", root->name); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1067 | mutex_unlock(&cgroup_mutex); |
| 1068 | return 0; |
| 1069 | } |
| 1070 | |
| 1071 | struct cgroup_sb_opts { |
| 1072 | unsigned long subsys_bits; |
| 1073 | unsigned long flags; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1074 | char *release_agent; |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 1075 | bool clone_children; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1076 | char *name; |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1077 | /* User explicitly requested empty subsystem */ |
| 1078 | bool none; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1079 | |
| 1080 | struct cgroupfs_root *new_root; |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1081 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1082 | }; |
| 1083 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1084 | /* |
| 1085 | * Convert a hierarchy specifier into a bitmask of subsystems and flags. Call |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1086 | * with cgroup_mutex held to protect the subsys[] array. This function takes |
| 1087 | * refcounts on subsystems to be used, unless it returns error, in which case |
| 1088 | * no refcounts are taken. |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1089 | */ |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1090 | static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1091 | { |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1092 | char *token, *o = data; |
| 1093 | bool all_ss = false, one_ss = false; |
Li Zefan | f9ab5b5 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 1094 | unsigned long mask = (unsigned long)-1; |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1095 | int i; |
| 1096 | bool module_pin_failed = false; |
Li Zefan | f9ab5b5 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 1097 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1098 | BUG_ON(!mutex_is_locked(&cgroup_mutex)); |
| 1099 | |
Li Zefan | f9ab5b5 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 1100 | #ifdef CONFIG_CPUSETS |
| 1101 | mask = ~(1UL << cpuset_subsys_id); |
| 1102 | #endif |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1103 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1104 | memset(opts, 0, sizeof(*opts)); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1105 | |
| 1106 | while ((token = strsep(&o, ",")) != NULL) { |
| 1107 | if (!*token) |
| 1108 | return -EINVAL; |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1109 | if (!strcmp(token, "none")) { |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1110 | /* Explicitly have no subsystems */ |
| 1111 | opts->none = true; |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1112 | continue; |
| 1113 | } |
| 1114 | if (!strcmp(token, "all")) { |
| 1115 | /* Mutually exclusive option 'all' + subsystem name */ |
| 1116 | if (one_ss) |
| 1117 | return -EINVAL; |
| 1118 | all_ss = true; |
| 1119 | continue; |
| 1120 | } |
| 1121 | if (!strcmp(token, "noprefix")) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1122 | set_bit(ROOT_NOPREFIX, &opts->flags); |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1123 | continue; |
| 1124 | } |
| 1125 | if (!strcmp(token, "clone_children")) { |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 1126 | opts->clone_children = true; |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1127 | continue; |
| 1128 | } |
| 1129 | if (!strncmp(token, "release_agent=", 14)) { |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1130 | /* Specifying two release agents is forbidden */ |
| 1131 | if (opts->release_agent) |
| 1132 | return -EINVAL; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1133 | opts->release_agent = |
Dan Carpenter | e400c28 | 2010-08-10 18:02:54 -0700 | [diff] [blame] | 1134 | kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1135 | if (!opts->release_agent) |
| 1136 | return -ENOMEM; |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1137 | continue; |
| 1138 | } |
| 1139 | if (!strncmp(token, "name=", 5)) { |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1140 | const char *name = token + 5; |
| 1141 | /* Can't specify an empty name */ |
| 1142 | if (!strlen(name)) |
| 1143 | return -EINVAL; |
| 1144 | /* Must match [\w.-]+ */ |
| 1145 | for (i = 0; i < strlen(name); i++) { |
| 1146 | char c = name[i]; |
| 1147 | if (isalnum(c)) |
| 1148 | continue; |
| 1149 | if ((c == '.') || (c == '-') || (c == '_')) |
| 1150 | continue; |
| 1151 | return -EINVAL; |
| 1152 | } |
| 1153 | /* Specifying two names is forbidden */ |
| 1154 | if (opts->name) |
| 1155 | return -EINVAL; |
| 1156 | opts->name = kstrndup(name, |
Dan Carpenter | e400c28 | 2010-08-10 18:02:54 -0700 | [diff] [blame] | 1157 | MAX_CGROUP_ROOT_NAMELEN - 1, |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1158 | GFP_KERNEL); |
| 1159 | if (!opts->name) |
| 1160 | return -ENOMEM; |
Daniel Lezcano | 32a8cf2 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1161 | |
| 1162 | continue; |
| 1163 | } |
| 1164 | |
| 1165 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 1166 | struct cgroup_subsys *ss = subsys[i]; |
| 1167 | if (ss == NULL) |
| 1168 | continue; |
| 1169 | if (strcmp(token, ss->name)) |
| 1170 | continue; |
| 1171 | if (ss->disabled) |
| 1172 | continue; |
| 1173 | |
| 1174 | /* Mutually exclusive option 'all' + subsystem name */ |
| 1175 | if (all_ss) |
| 1176 | return -EINVAL; |
| 1177 | set_bit(i, &opts->subsys_bits); |
| 1178 | one_ss = true; |
| 1179 | |
| 1180 | break; |
| 1181 | } |
| 1182 | if (i == CGROUP_SUBSYS_COUNT) |
| 1183 | return -ENOENT; |
| 1184 | } |
| 1185 | |
| 1186 | /* |
| 1187 | * If the 'all' option was specified select all the subsystems, |
| 1188 | * otherwise 'all, 'none' and a subsystem name options were not |
| 1189 | * specified, let's default to 'all' |
| 1190 | */ |
| 1191 | if (all_ss || (!all_ss && !one_ss && !opts->none)) { |
| 1192 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 1193 | struct cgroup_subsys *ss = subsys[i]; |
| 1194 | if (ss == NULL) |
| 1195 | continue; |
| 1196 | if (ss->disabled) |
| 1197 | continue; |
| 1198 | set_bit(i, &opts->subsys_bits); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1199 | } |
| 1200 | } |
| 1201 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1202 | /* Consistency checks */ |
| 1203 | |
Li Zefan | f9ab5b5 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 1204 | /* |
| 1205 | * Option noprefix was introduced just for backward compatibility |
| 1206 | * with the old cpuset, so we allow noprefix only if mounting just |
| 1207 | * the cpuset subsystem. |
| 1208 | */ |
| 1209 | if (test_bit(ROOT_NOPREFIX, &opts->flags) && |
| 1210 | (opts->subsys_bits & mask)) |
| 1211 | return -EINVAL; |
| 1212 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1213 | |
| 1214 | /* Can't specify "none" and some subsystems */ |
| 1215 | if (opts->subsys_bits && opts->none) |
| 1216 | return -EINVAL; |
| 1217 | |
| 1218 | /* |
| 1219 | * We either have to specify by name or by subsystems. (So all |
| 1220 | * empty hierarchies must have a name). |
| 1221 | */ |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1222 | if (!opts->subsys_bits && !opts->name) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1223 | return -EINVAL; |
| 1224 | |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1225 | /* |
| 1226 | * Grab references on all the modules we'll need, so the subsystems |
| 1227 | * don't dance around before rebind_subsystems attaches them. This may |
| 1228 | * take duplicate reference counts on a subsystem that's already used, |
| 1229 | * but rebind_subsystems handles this case. |
| 1230 | */ |
| 1231 | for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { |
| 1232 | unsigned long bit = 1UL << i; |
| 1233 | |
| 1234 | if (!(bit & opts->subsys_bits)) |
| 1235 | continue; |
| 1236 | if (!try_module_get(subsys[i]->module)) { |
| 1237 | module_pin_failed = true; |
| 1238 | break; |
| 1239 | } |
| 1240 | } |
| 1241 | if (module_pin_failed) { |
| 1242 | /* |
| 1243 | * oops, one of the modules was going away. this means that we |
| 1244 | * raced with a module_delete call, and to the user this is |
| 1245 | * essentially a "subsystem doesn't exist" case. |
| 1246 | */ |
| 1247 | for (i--; i >= CGROUP_BUILTIN_SUBSYS_COUNT; i--) { |
| 1248 | /* drop refcounts only on the ones we took */ |
| 1249 | unsigned long bit = 1UL << i; |
| 1250 | |
| 1251 | if (!(bit & opts->subsys_bits)) |
| 1252 | continue; |
| 1253 | module_put(subsys[i]->module); |
| 1254 | } |
| 1255 | return -ENOENT; |
| 1256 | } |
| 1257 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1258 | return 0; |
| 1259 | } |
| 1260 | |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1261 | static void drop_parsed_module_refcounts(unsigned long subsys_bits) |
| 1262 | { |
| 1263 | int i; |
| 1264 | for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { |
| 1265 | unsigned long bit = 1UL << i; |
| 1266 | |
| 1267 | if (!(bit & subsys_bits)) |
| 1268 | continue; |
| 1269 | module_put(subsys[i]->module); |
| 1270 | } |
| 1271 | } |
| 1272 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1273 | static int cgroup_remount(struct super_block *sb, int *flags, char *data) |
| 1274 | { |
| 1275 | int ret = 0; |
| 1276 | struct cgroupfs_root *root = sb->s_fs_info; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1277 | struct cgroup *cgrp = &root->top_cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1278 | struct cgroup_sb_opts opts; |
| 1279 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1280 | mutex_lock(&cgrp->dentry->d_inode->i_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1281 | mutex_lock(&cgroup_mutex); |
| 1282 | |
| 1283 | /* See what subsystems are wanted */ |
| 1284 | ret = parse_cgroupfs_options(data, &opts); |
| 1285 | if (ret) |
| 1286 | goto out_unlock; |
| 1287 | |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1288 | /* Don't allow flags or name to change at remount */ |
| 1289 | if (opts.flags != root->flags || |
| 1290 | (opts.name && strcmp(opts.name, root->name))) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1291 | ret = -EINVAL; |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1292 | drop_parsed_module_refcounts(opts.subsys_bits); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1293 | goto out_unlock; |
| 1294 | } |
| 1295 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1296 | ret = rebind_subsystems(root, opts.subsys_bits); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1297 | if (ret) { |
| 1298 | drop_parsed_module_refcounts(opts.subsys_bits); |
Li Zefan | 0670e08 | 2009-04-02 16:57:30 -0700 | [diff] [blame] | 1299 | goto out_unlock; |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1300 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1301 | |
| 1302 | /* (re)populate subsystem files */ |
Li Zefan | 0670e08 | 2009-04-02 16:57:30 -0700 | [diff] [blame] | 1303 | cgroup_populate_dir(cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1304 | |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1305 | if (opts.release_agent) |
| 1306 | strcpy(root->release_agent_path, opts.release_agent); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1307 | out_unlock: |
Jesper Juhl | 66bdc9c | 2009-04-02 16:57:27 -0700 | [diff] [blame] | 1308 | kfree(opts.release_agent); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1309 | kfree(opts.name); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1310 | mutex_unlock(&cgroup_mutex); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1311 | mutex_unlock(&cgrp->dentry->d_inode->i_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1312 | return ret; |
| 1313 | } |
| 1314 | |
Alexey Dobriyan | b87221d | 2009-09-21 17:01:09 -0700 | [diff] [blame] | 1315 | static const struct super_operations cgroup_ops = { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1316 | .statfs = simple_statfs, |
| 1317 | .drop_inode = generic_delete_inode, |
| 1318 | .show_options = cgroup_show_options, |
| 1319 | .remount_fs = cgroup_remount, |
| 1320 | }; |
| 1321 | |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 1322 | static void init_cgroup_housekeeping(struct cgroup *cgrp) |
| 1323 | { |
| 1324 | INIT_LIST_HEAD(&cgrp->sibling); |
| 1325 | INIT_LIST_HEAD(&cgrp->children); |
| 1326 | INIT_LIST_HEAD(&cgrp->css_sets); |
| 1327 | INIT_LIST_HEAD(&cgrp->release_list); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 1328 | INIT_LIST_HEAD(&cgrp->pidlists); |
| 1329 | mutex_init(&cgrp->pidlist_mutex); |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 1330 | INIT_LIST_HEAD(&cgrp->event_list); |
| 1331 | spin_lock_init(&cgrp->event_list_lock); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 1332 | } |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1333 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1334 | static void init_cgroup_root(struct cgroupfs_root *root) |
| 1335 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1336 | struct cgroup *cgrp = &root->top_cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1337 | INIT_LIST_HEAD(&root->subsys_list); |
| 1338 | INIT_LIST_HEAD(&root->root_list); |
| 1339 | root->number_of_cgroups = 1; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1340 | cgrp->root = root; |
| 1341 | cgrp->top_cgroup = cgrp; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 1342 | init_cgroup_housekeeping(cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1343 | } |
| 1344 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1345 | static bool init_root_id(struct cgroupfs_root *root) |
| 1346 | { |
| 1347 | int ret = 0; |
| 1348 | |
| 1349 | do { |
| 1350 | if (!ida_pre_get(&hierarchy_ida, GFP_KERNEL)) |
| 1351 | return false; |
| 1352 | spin_lock(&hierarchy_id_lock); |
| 1353 | /* Try to allocate the next unused ID */ |
| 1354 | ret = ida_get_new_above(&hierarchy_ida, next_hierarchy_id, |
| 1355 | &root->hierarchy_id); |
| 1356 | if (ret == -ENOSPC) |
| 1357 | /* Try again starting from 0 */ |
| 1358 | ret = ida_get_new(&hierarchy_ida, &root->hierarchy_id); |
| 1359 | if (!ret) { |
| 1360 | next_hierarchy_id = root->hierarchy_id + 1; |
| 1361 | } else if (ret != -EAGAIN) { |
| 1362 | /* Can only get here if the 31-bit IDR is full ... */ |
| 1363 | BUG_ON(ret); |
| 1364 | } |
| 1365 | spin_unlock(&hierarchy_id_lock); |
| 1366 | } while (ret); |
| 1367 | return true; |
| 1368 | } |
| 1369 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1370 | static int cgroup_test_super(struct super_block *sb, void *data) |
| 1371 | { |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1372 | struct cgroup_sb_opts *opts = data; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1373 | struct cgroupfs_root *root = sb->s_fs_info; |
| 1374 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1375 | /* If we asked for a name then it must match */ |
| 1376 | if (opts->name && strcmp(opts->name, root->name)) |
| 1377 | return 0; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1378 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1379 | /* |
| 1380 | * If we asked for subsystems (or explicitly for no |
| 1381 | * subsystems) then they must match |
| 1382 | */ |
| 1383 | if ((opts->subsys_bits || opts->none) |
| 1384 | && (opts->subsys_bits != root->subsys_bits)) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1385 | return 0; |
| 1386 | |
| 1387 | return 1; |
| 1388 | } |
| 1389 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1390 | static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts) |
| 1391 | { |
| 1392 | struct cgroupfs_root *root; |
| 1393 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1394 | if (!opts->subsys_bits && !opts->none) |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1395 | return NULL; |
| 1396 | |
| 1397 | root = kzalloc(sizeof(*root), GFP_KERNEL); |
| 1398 | if (!root) |
| 1399 | return ERR_PTR(-ENOMEM); |
| 1400 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1401 | if (!init_root_id(root)) { |
| 1402 | kfree(root); |
| 1403 | return ERR_PTR(-ENOMEM); |
| 1404 | } |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1405 | init_cgroup_root(root); |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1406 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1407 | root->subsys_bits = opts->subsys_bits; |
| 1408 | root->flags = opts->flags; |
| 1409 | if (opts->release_agent) |
| 1410 | strcpy(root->release_agent_path, opts->release_agent); |
| 1411 | if (opts->name) |
| 1412 | strcpy(root->name, opts->name); |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 1413 | if (opts->clone_children) |
| 1414 | set_bit(CGRP_CLONE_CHILDREN, &root->top_cgroup.flags); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1415 | return root; |
| 1416 | } |
| 1417 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1418 | static void cgroup_drop_root(struct cgroupfs_root *root) |
| 1419 | { |
| 1420 | if (!root) |
| 1421 | return; |
| 1422 | |
| 1423 | BUG_ON(!root->hierarchy_id); |
| 1424 | spin_lock(&hierarchy_id_lock); |
| 1425 | ida_remove(&hierarchy_ida, root->hierarchy_id); |
| 1426 | spin_unlock(&hierarchy_id_lock); |
| 1427 | kfree(root); |
| 1428 | } |
| 1429 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1430 | static int cgroup_set_super(struct super_block *sb, void *data) |
| 1431 | { |
| 1432 | int ret; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1433 | struct cgroup_sb_opts *opts = data; |
| 1434 | |
| 1435 | /* If we don't have a new root, we can't set up a new sb */ |
| 1436 | if (!opts->new_root) |
| 1437 | return -EINVAL; |
| 1438 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1439 | BUG_ON(!opts->subsys_bits && !opts->none); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1440 | |
| 1441 | ret = set_anon_super(sb, NULL); |
| 1442 | if (ret) |
| 1443 | return ret; |
| 1444 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1445 | sb->s_fs_info = opts->new_root; |
| 1446 | opts->new_root->sb = sb; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1447 | |
| 1448 | sb->s_blocksize = PAGE_CACHE_SIZE; |
| 1449 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| 1450 | sb->s_magic = CGROUP_SUPER_MAGIC; |
| 1451 | sb->s_op = &cgroup_ops; |
| 1452 | |
| 1453 | return 0; |
| 1454 | } |
| 1455 | |
| 1456 | static int cgroup_get_rootdir(struct super_block *sb) |
| 1457 | { |
Al Viro | 0df6a63 | 2010-12-21 13:29:29 -0500 | [diff] [blame] | 1458 | static const struct dentry_operations cgroup_dops = { |
| 1459 | .d_iput = cgroup_diput, |
Al Viro | c72a04e | 2011-01-14 05:31:45 +0000 | [diff] [blame] | 1460 | .d_delete = cgroup_delete, |
Al Viro | 0df6a63 | 2010-12-21 13:29:29 -0500 | [diff] [blame] | 1461 | }; |
| 1462 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1463 | struct inode *inode = |
| 1464 | cgroup_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR, sb); |
| 1465 | struct dentry *dentry; |
| 1466 | |
| 1467 | if (!inode) |
| 1468 | return -ENOMEM; |
| 1469 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1470 | inode->i_fop = &simple_dir_operations; |
| 1471 | inode->i_op = &cgroup_dir_inode_operations; |
| 1472 | /* directories start off with i_nlink == 2 (for "." entry) */ |
| 1473 | inc_nlink(inode); |
| 1474 | dentry = d_alloc_root(inode); |
| 1475 | if (!dentry) { |
| 1476 | iput(inode); |
| 1477 | return -ENOMEM; |
| 1478 | } |
| 1479 | sb->s_root = dentry; |
Al Viro | 0df6a63 | 2010-12-21 13:29:29 -0500 | [diff] [blame] | 1480 | /* for everything else we want ->d_op set */ |
| 1481 | sb->s_d_op = &cgroup_dops; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1482 | return 0; |
| 1483 | } |
| 1484 | |
Al Viro | f7e8357 | 2010-07-26 13:23:11 +0400 | [diff] [blame] | 1485 | static struct dentry *cgroup_mount(struct file_system_type *fs_type, |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1486 | int flags, const char *unused_dev_name, |
Al Viro | f7e8357 | 2010-07-26 13:23:11 +0400 | [diff] [blame] | 1487 | void *data) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1488 | { |
| 1489 | struct cgroup_sb_opts opts; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1490 | struct cgroupfs_root *root; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1491 | int ret = 0; |
| 1492 | struct super_block *sb; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1493 | struct cgroupfs_root *new_root; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1494 | |
| 1495 | /* First find the desired set of subsystems */ |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1496 | mutex_lock(&cgroup_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1497 | ret = parse_cgroupfs_options(data, &opts); |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 1498 | mutex_unlock(&cgroup_mutex); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1499 | if (ret) |
| 1500 | goto out_err; |
| 1501 | |
| 1502 | /* |
| 1503 | * Allocate a new cgroup root. We may not need it if we're |
| 1504 | * reusing an existing hierarchy. |
| 1505 | */ |
| 1506 | new_root = cgroup_root_from_opts(&opts); |
| 1507 | if (IS_ERR(new_root)) { |
| 1508 | ret = PTR_ERR(new_root); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1509 | goto drop_modules; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 1510 | } |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1511 | opts.new_root = new_root; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1512 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1513 | /* Locate an existing or new sb for this hierarchy */ |
| 1514 | sb = sget(fs_type, cgroup_test_super, cgroup_set_super, &opts); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1515 | if (IS_ERR(sb)) { |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1516 | ret = PTR_ERR(sb); |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1517 | cgroup_drop_root(opts.new_root); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1518 | goto drop_modules; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1519 | } |
| 1520 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1521 | root = sb->s_fs_info; |
| 1522 | BUG_ON(!root); |
| 1523 | if (root == opts.new_root) { |
| 1524 | /* We used the new root structure, so this is a new hierarchy */ |
| 1525 | struct list_head tmp_cg_links; |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1526 | struct cgroup *root_cgrp = &root->top_cgroup; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1527 | struct inode *inode; |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1528 | struct cgroupfs_root *existing_root; |
Li Zefan | 28fd5df | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 1529 | int i; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1530 | |
| 1531 | BUG_ON(sb->s_root != NULL); |
| 1532 | |
| 1533 | ret = cgroup_get_rootdir(sb); |
| 1534 | if (ret) |
| 1535 | goto drop_new_super; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1536 | inode = sb->s_root->d_inode; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1537 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1538 | mutex_lock(&inode->i_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1539 | mutex_lock(&cgroup_mutex); |
| 1540 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1541 | if (strlen(root->name)) { |
| 1542 | /* Check for name clashes with existing mounts */ |
| 1543 | for_each_active_root(existing_root) { |
| 1544 | if (!strcmp(existing_root->name, root->name)) { |
| 1545 | ret = -EBUSY; |
| 1546 | mutex_unlock(&cgroup_mutex); |
| 1547 | mutex_unlock(&inode->i_mutex); |
| 1548 | goto drop_new_super; |
| 1549 | } |
| 1550 | } |
| 1551 | } |
| 1552 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1553 | /* |
| 1554 | * We're accessing css_set_count without locking |
| 1555 | * css_set_lock here, but that's OK - it can only be |
| 1556 | * increased by someone holding cgroup_lock, and |
| 1557 | * that's us. The worst that can happen is that we |
| 1558 | * have some link structures left over |
| 1559 | */ |
| 1560 | ret = allocate_cg_links(css_set_count, &tmp_cg_links); |
| 1561 | if (ret) { |
| 1562 | mutex_unlock(&cgroup_mutex); |
| 1563 | mutex_unlock(&inode->i_mutex); |
| 1564 | goto drop_new_super; |
| 1565 | } |
| 1566 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1567 | ret = rebind_subsystems(root, root->subsys_bits); |
| 1568 | if (ret == -EBUSY) { |
| 1569 | mutex_unlock(&cgroup_mutex); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1570 | mutex_unlock(&inode->i_mutex); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1571 | free_cg_links(&tmp_cg_links); |
| 1572 | goto drop_new_super; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1573 | } |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1574 | /* |
| 1575 | * There must be no failure case after here, since rebinding |
| 1576 | * takes care of subsystems' refcounts, which are explicitly |
| 1577 | * dropped in the failure exit path. |
| 1578 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1579 | |
| 1580 | /* EBUSY should be the only error here */ |
| 1581 | BUG_ON(ret); |
| 1582 | |
| 1583 | list_add(&root->root_list, &roots); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1584 | root_count++; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1585 | |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1586 | sb->s_root->d_fsdata = root_cgrp; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1587 | root->top_cgroup.dentry = sb->s_root; |
| 1588 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1589 | /* Link the top cgroup in this hierarchy into all |
| 1590 | * the css_set objects */ |
| 1591 | write_lock(&css_set_lock); |
Li Zefan | 28fd5df | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 1592 | for (i = 0; i < CSS_SET_TABLE_SIZE; i++) { |
| 1593 | struct hlist_head *hhead = &css_set_table[i]; |
| 1594 | struct hlist_node *node; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1595 | struct css_set *cg; |
Li Zefan | 28fd5df | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 1596 | |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1597 | hlist_for_each_entry(cg, node, hhead, hlist) |
| 1598 | link_css_set(&tmp_cg_links, cg, root_cgrp); |
Li Zefan | 28fd5df | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 1599 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1600 | write_unlock(&css_set_lock); |
| 1601 | |
| 1602 | free_cg_links(&tmp_cg_links); |
| 1603 | |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1604 | BUG_ON(!list_empty(&root_cgrp->sibling)); |
| 1605 | BUG_ON(!list_empty(&root_cgrp->children)); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1606 | BUG_ON(root->number_of_cgroups != 1); |
| 1607 | |
Li Zefan | c12f65d | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 1608 | cgroup_populate_dir(root_cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1609 | mutex_unlock(&cgroup_mutex); |
Xiaotian Feng | 34f77a9 | 2009-09-23 15:56:18 -0700 | [diff] [blame] | 1610 | mutex_unlock(&inode->i_mutex); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1611 | } else { |
| 1612 | /* |
| 1613 | * We re-used an existing hierarchy - the new root (if |
| 1614 | * any) is not needed |
| 1615 | */ |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1616 | cgroup_drop_root(opts.new_root); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1617 | /* no subsys rebinding, so refcounts don't change */ |
| 1618 | drop_parsed_module_refcounts(opts.subsys_bits); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1619 | } |
| 1620 | |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1621 | kfree(opts.release_agent); |
| 1622 | kfree(opts.name); |
Al Viro | f7e8357 | 2010-07-26 13:23:11 +0400 | [diff] [blame] | 1623 | return dget(sb->s_root); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1624 | |
| 1625 | drop_new_super: |
Al Viro | 6f5bbff | 2009-05-06 01:34:22 -0400 | [diff] [blame] | 1626 | deactivate_locked_super(sb); |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 1627 | drop_modules: |
| 1628 | drop_parsed_module_refcounts(opts.subsys_bits); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 1629 | out_err: |
| 1630 | kfree(opts.release_agent); |
| 1631 | kfree(opts.name); |
Al Viro | f7e8357 | 2010-07-26 13:23:11 +0400 | [diff] [blame] | 1632 | return ERR_PTR(ret); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1633 | } |
| 1634 | |
| 1635 | static void cgroup_kill_sb(struct super_block *sb) { |
| 1636 | struct cgroupfs_root *root = sb->s_fs_info; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1637 | struct cgroup *cgrp = &root->top_cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1638 | int ret; |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 1639 | struct cg_cgroup_link *link; |
| 1640 | struct cg_cgroup_link *saved_link; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1641 | |
| 1642 | BUG_ON(!root); |
| 1643 | |
| 1644 | BUG_ON(root->number_of_cgroups != 1); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1645 | BUG_ON(!list_empty(&cgrp->children)); |
| 1646 | BUG_ON(!list_empty(&cgrp->sibling)); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1647 | |
| 1648 | mutex_lock(&cgroup_mutex); |
| 1649 | |
| 1650 | /* Rebind all subsystems back to the default hierarchy */ |
| 1651 | ret = rebind_subsystems(root, 0); |
| 1652 | /* Shouldn't be able to fail ... */ |
| 1653 | BUG_ON(ret); |
| 1654 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1655 | /* |
| 1656 | * Release all the links from css_sets to this hierarchy's |
| 1657 | * root cgroup |
| 1658 | */ |
| 1659 | write_lock(&css_set_lock); |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 1660 | |
| 1661 | list_for_each_entry_safe(link, saved_link, &cgrp->css_sets, |
| 1662 | cgrp_link_list) { |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1663 | list_del(&link->cg_link_list); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1664 | list_del(&link->cgrp_link_list); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1665 | kfree(link); |
| 1666 | } |
| 1667 | write_unlock(&css_set_lock); |
| 1668 | |
Paul Menage | 839ec54 | 2009-01-29 14:25:22 -0800 | [diff] [blame] | 1669 | if (!list_empty(&root->root_list)) { |
| 1670 | list_del(&root->root_list); |
| 1671 | root_count--; |
| 1672 | } |
Li Zefan | e5f6a86 | 2009-01-07 18:07:41 -0800 | [diff] [blame] | 1673 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1674 | mutex_unlock(&cgroup_mutex); |
| 1675 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1676 | kill_litter_super(sb); |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 1677 | cgroup_drop_root(root); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1678 | } |
| 1679 | |
| 1680 | static struct file_system_type cgroup_fs_type = { |
| 1681 | .name = "cgroup", |
Al Viro | f7e8357 | 2010-07-26 13:23:11 +0400 | [diff] [blame] | 1682 | .mount = cgroup_mount, |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1683 | .kill_sb = cgroup_kill_sb, |
| 1684 | }; |
| 1685 | |
Greg KH | 676db4a | 2010-08-05 13:53:35 -0700 | [diff] [blame] | 1686 | static struct kobject *cgroup_kobj; |
| 1687 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1688 | static inline struct cgroup *__d_cgrp(struct dentry *dentry) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1689 | { |
| 1690 | return dentry->d_fsdata; |
| 1691 | } |
| 1692 | |
| 1693 | static inline struct cftype *__d_cft(struct dentry *dentry) |
| 1694 | { |
| 1695 | return dentry->d_fsdata; |
| 1696 | } |
| 1697 | |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 1698 | /** |
| 1699 | * cgroup_path - generate the path of a cgroup |
| 1700 | * @cgrp: the cgroup in question |
| 1701 | * @buf: the buffer to write the path into |
| 1702 | * @buflen: the length of the buffer |
| 1703 | * |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 1704 | * Called with cgroup_mutex held or else with an RCU-protected cgroup |
| 1705 | * reference. Writes path of cgroup into buf. Returns 0 on success, |
| 1706 | * -errno on error. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1707 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1708 | int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1709 | { |
| 1710 | char *start; |
Li Zefan | 9a9686b | 2010-04-22 17:29:24 +0800 | [diff] [blame] | 1711 | struct dentry *dentry = rcu_dereference_check(cgrp->dentry, |
| 1712 | rcu_read_lock_held() || |
| 1713 | cgroup_lock_is_held()); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1714 | |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 1715 | if (!dentry || cgrp == dummytop) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1716 | /* |
| 1717 | * Inactive subsystems have no dentry for their root |
| 1718 | * cgroup |
| 1719 | */ |
| 1720 | strcpy(buf, "/"); |
| 1721 | return 0; |
| 1722 | } |
| 1723 | |
| 1724 | start = buf + buflen; |
| 1725 | |
| 1726 | *--start = '\0'; |
| 1727 | for (;;) { |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 1728 | int len = dentry->d_name.len; |
Li Zefan | 9a9686b | 2010-04-22 17:29:24 +0800 | [diff] [blame] | 1729 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1730 | if ((start -= len) < buf) |
| 1731 | return -ENAMETOOLONG; |
Li Zefan | 9a9686b | 2010-04-22 17:29:24 +0800 | [diff] [blame] | 1732 | memcpy(start, dentry->d_name.name, len); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1733 | cgrp = cgrp->parent; |
| 1734 | if (!cgrp) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1735 | break; |
Li Zefan | 9a9686b | 2010-04-22 17:29:24 +0800 | [diff] [blame] | 1736 | |
| 1737 | dentry = rcu_dereference_check(cgrp->dentry, |
| 1738 | rcu_read_lock_held() || |
| 1739 | cgroup_lock_is_held()); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1740 | if (!cgrp->parent) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1741 | continue; |
| 1742 | if (--start < buf) |
| 1743 | return -ENAMETOOLONG; |
| 1744 | *start = '/'; |
| 1745 | } |
| 1746 | memmove(buf, start, buf + buflen - start); |
| 1747 | return 0; |
| 1748 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 1749 | EXPORT_SYMBOL_GPL(cgroup_path); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 1750 | |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 1751 | /** |
| 1752 | * cgroup_attach_task - attach task 'tsk' to cgroup 'cgrp' |
| 1753 | * @cgrp: the cgroup the task is attaching to |
| 1754 | * @tsk: the task to be attached |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1755 | * |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 1756 | * Call holding cgroup_mutex. May take task_lock of |
| 1757 | * the task 'tsk' during call. |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1758 | */ |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 1759 | int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1760 | { |
| 1761 | int retval = 0; |
Daisuke Nishimura | 2468c72 | 2010-03-10 15:22:03 -0800 | [diff] [blame] | 1762 | struct cgroup_subsys *ss, *failed_ss = NULL; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1763 | struct cgroup *oldcgrp; |
Lai Jiangshan | 77efecd | 2009-01-07 18:07:39 -0800 | [diff] [blame] | 1764 | struct css_set *cg; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1765 | struct css_set *newcg; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1766 | struct cgroupfs_root *root = cgrp->root; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1767 | |
| 1768 | /* Nothing to do if the task is already in that cgroup */ |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 1769 | oldcgrp = task_cgroup_from_root(tsk, root); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1770 | if (cgrp == oldcgrp) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1771 | return 0; |
| 1772 | |
| 1773 | for_each_subsys(root, ss) { |
| 1774 | if (ss->can_attach) { |
Ben Blum | be367d0 | 2009-09-23 15:56:31 -0700 | [diff] [blame] | 1775 | retval = ss->can_attach(ss, cgrp, tsk, false); |
Daisuke Nishimura | 2468c72 | 2010-03-10 15:22:03 -0800 | [diff] [blame] | 1776 | if (retval) { |
| 1777 | /* |
| 1778 | * Remember on which subsystem the can_attach() |
| 1779 | * failed, so that we only call cancel_attach() |
| 1780 | * against the subsystems whose can_attach() |
| 1781 | * succeeded. (See below) |
| 1782 | */ |
| 1783 | failed_ss = ss; |
| 1784 | goto out; |
| 1785 | } |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1786 | } |
| 1787 | } |
| 1788 | |
Lai Jiangshan | 77efecd | 2009-01-07 18:07:39 -0800 | [diff] [blame] | 1789 | task_lock(tsk); |
| 1790 | cg = tsk->cgroups; |
| 1791 | get_css_set(cg); |
| 1792 | task_unlock(tsk); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1793 | /* |
| 1794 | * Locate or allocate a new css_set for this task, |
| 1795 | * based on its final set of cgroups |
| 1796 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1797 | newcg = find_css_set(cg, cgrp); |
Lai Jiangshan | 77efecd | 2009-01-07 18:07:39 -0800 | [diff] [blame] | 1798 | put_css_set(cg); |
Daisuke Nishimura | 2468c72 | 2010-03-10 15:22:03 -0800 | [diff] [blame] | 1799 | if (!newcg) { |
| 1800 | retval = -ENOMEM; |
| 1801 | goto out; |
| 1802 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1803 | |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1804 | task_lock(tsk); |
| 1805 | if (tsk->flags & PF_EXITING) { |
| 1806 | task_unlock(tsk); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1807 | put_css_set(newcg); |
Daisuke Nishimura | 2468c72 | 2010-03-10 15:22:03 -0800 | [diff] [blame] | 1808 | retval = -ESRCH; |
| 1809 | goto out; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1810 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1811 | rcu_assign_pointer(tsk->cgroups, newcg); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1812 | task_unlock(tsk); |
| 1813 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1814 | /* Update the css_set linked lists if we're using them */ |
| 1815 | write_lock(&css_set_lock); |
| 1816 | if (!list_empty(&tsk->cg_list)) { |
| 1817 | list_del(&tsk->cg_list); |
| 1818 | list_add(&tsk->cg_list, &newcg->tasks); |
| 1819 | } |
| 1820 | write_unlock(&css_set_lock); |
| 1821 | |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1822 | for_each_subsys(root, ss) { |
Paul Jackson | e18f631 | 2008-02-07 00:13:44 -0800 | [diff] [blame] | 1823 | if (ss->attach) |
Ben Blum | be367d0 | 2009-09-23 15:56:31 -0700 | [diff] [blame] | 1824 | ss->attach(ss, cgrp, oldcgrp, tsk, false); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1825 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 1826 | set_bit(CGRP_RELEASABLE, &oldcgrp->flags); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1827 | synchronize_rcu(); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1828 | put_css_set(cg); |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 1829 | |
| 1830 | /* |
| 1831 | * wake up rmdir() waiter. the rmdir should fail since the cgroup |
| 1832 | * is no longer empty. |
| 1833 | */ |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 1834 | cgroup_wakeup_rmdir_waiter(cgrp); |
Daisuke Nishimura | 2468c72 | 2010-03-10 15:22:03 -0800 | [diff] [blame] | 1835 | out: |
| 1836 | if (retval) { |
| 1837 | for_each_subsys(root, ss) { |
| 1838 | if (ss == failed_ss) |
| 1839 | /* |
| 1840 | * This subsystem was the one that failed the |
| 1841 | * can_attach() check earlier, so we don't need |
| 1842 | * to call cancel_attach() against it or any |
| 1843 | * remaining subsystems. |
| 1844 | */ |
| 1845 | break; |
| 1846 | if (ss->cancel_attach) |
| 1847 | ss->cancel_attach(ss, cgrp, tsk, false); |
| 1848 | } |
| 1849 | } |
| 1850 | return retval; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1851 | } |
| 1852 | |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1853 | /** |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 1854 | * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from' |
| 1855 | * @from: attach to all cgroups of a given task |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1856 | * @tsk: the task to be attached |
| 1857 | */ |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 1858 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1859 | { |
| 1860 | struct cgroupfs_root *root; |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1861 | int retval = 0; |
| 1862 | |
| 1863 | cgroup_lock(); |
| 1864 | for_each_active_root(root) { |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 1865 | struct cgroup *from_cg = task_cgroup_from_root(from, root); |
| 1866 | |
| 1867 | retval = cgroup_attach_task(from_cg, tsk); |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1868 | if (retval) |
| 1869 | break; |
| 1870 | } |
| 1871 | cgroup_unlock(); |
| 1872 | |
| 1873 | return retval; |
| 1874 | } |
Michael S. Tsirkin | 31583bb | 2010-09-09 16:37:37 -0700 | [diff] [blame] | 1875 | EXPORT_SYMBOL_GPL(cgroup_attach_task_all); |
Sridhar Samudrala | d7926ee | 2010-05-30 22:24:39 +0200 | [diff] [blame] | 1876 | |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1877 | /* |
Paul Menage | af35102 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 1878 | * Attach task with pid 'pid' to cgroup 'cgrp'. Call with cgroup_mutex |
| 1879 | * held. May take task_lock of task |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1880 | */ |
Paul Menage | af35102 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 1881 | static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1882 | { |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1883 | struct task_struct *tsk; |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 1884 | const struct cred *cred = current_cred(), *tcred; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1885 | int ret; |
| 1886 | |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1887 | if (pid) { |
| 1888 | rcu_read_lock(); |
Pavel Emelyanov | 73507f3 | 2008-02-07 00:14:47 -0800 | [diff] [blame] | 1889 | tsk = find_task_by_vpid(pid); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1890 | if (!tsk || tsk->flags & PF_EXITING) { |
| 1891 | rcu_read_unlock(); |
| 1892 | return -ESRCH; |
| 1893 | } |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1894 | |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 1895 | tcred = __task_cred(tsk); |
| 1896 | if (cred->euid && |
| 1897 | cred->euid != tcred->uid && |
| 1898 | cred->euid != tcred->suid) { |
| 1899 | rcu_read_unlock(); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1900 | return -EACCES; |
| 1901 | } |
David Howells | c69e8d9 | 2008-11-14 10:39:19 +1100 | [diff] [blame] | 1902 | get_task_struct(tsk); |
| 1903 | rcu_read_unlock(); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1904 | } else { |
| 1905 | tsk = current; |
| 1906 | get_task_struct(tsk); |
| 1907 | } |
| 1908 | |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 1909 | ret = cgroup_attach_task(cgrp, tsk); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 1910 | put_task_struct(tsk); |
| 1911 | return ret; |
| 1912 | } |
| 1913 | |
Paul Menage | af35102 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 1914 | static int cgroup_tasks_write(struct cgroup *cgrp, struct cftype *cft, u64 pid) |
| 1915 | { |
| 1916 | int ret; |
| 1917 | if (!cgroup_lock_live_group(cgrp)) |
| 1918 | return -ENODEV; |
| 1919 | ret = attach_task_by_pid(cgrp, pid); |
| 1920 | cgroup_unlock(); |
| 1921 | return ret; |
| 1922 | } |
| 1923 | |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1924 | /** |
| 1925 | * cgroup_lock_live_group - take cgroup_mutex and check that cgrp is alive. |
| 1926 | * @cgrp: the cgroup to be checked for liveness |
| 1927 | * |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1928 | * On success, returns true; the lock should be later released with |
| 1929 | * cgroup_unlock(). On failure returns false with no lock held. |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1930 | */ |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1931 | bool cgroup_lock_live_group(struct cgroup *cgrp) |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1932 | { |
| 1933 | mutex_lock(&cgroup_mutex); |
| 1934 | if (cgroup_is_removed(cgrp)) { |
| 1935 | mutex_unlock(&cgroup_mutex); |
| 1936 | return false; |
| 1937 | } |
| 1938 | return true; |
| 1939 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 1940 | EXPORT_SYMBOL_GPL(cgroup_lock_live_group); |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1941 | |
| 1942 | static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft, |
| 1943 | const char *buffer) |
| 1944 | { |
| 1945 | BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX); |
Evgeny Kuznetsov | f4a2589 | 2010-10-27 15:33:37 -0700 | [diff] [blame] | 1946 | if (strlen(buffer) >= PATH_MAX) |
| 1947 | return -EINVAL; |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1948 | if (!cgroup_lock_live_group(cgrp)) |
| 1949 | return -ENODEV; |
| 1950 | strcpy(cgrp->root->release_agent_path, buffer); |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1951 | cgroup_unlock(); |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1952 | return 0; |
| 1953 | } |
| 1954 | |
| 1955 | static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft, |
| 1956 | struct seq_file *seq) |
| 1957 | { |
| 1958 | if (!cgroup_lock_live_group(cgrp)) |
| 1959 | return -ENODEV; |
| 1960 | seq_puts(seq, cgrp->root->release_agent_path); |
| 1961 | seq_putc(seq, '\n'); |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1962 | cgroup_unlock(); |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 1963 | return 0; |
| 1964 | } |
| 1965 | |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1966 | /* A buffer size big enough for numbers or short strings */ |
| 1967 | #define CGROUP_LOCAL_BUFFER_SIZE 64 |
| 1968 | |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 1969 | static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft, |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 1970 | struct file *file, |
| 1971 | const char __user *userbuf, |
| 1972 | size_t nbytes, loff_t *unused_ppos) |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1973 | { |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 1974 | char buffer[CGROUP_LOCAL_BUFFER_SIZE]; |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1975 | int retval = 0; |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1976 | char *end; |
| 1977 | |
| 1978 | if (!nbytes) |
| 1979 | return -EINVAL; |
| 1980 | if (nbytes >= sizeof(buffer)) |
| 1981 | return -E2BIG; |
| 1982 | if (copy_from_user(buffer, userbuf, nbytes)) |
| 1983 | return -EFAULT; |
| 1984 | |
| 1985 | buffer[nbytes] = 0; /* nul-terminate */ |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 1986 | if (cft->write_u64) { |
KOSAKI Motohiro | 478988d | 2009-10-26 16:49:36 -0700 | [diff] [blame] | 1987 | u64 val = simple_strtoull(strstrip(buffer), &end, 0); |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 1988 | if (*end) |
| 1989 | return -EINVAL; |
| 1990 | retval = cft->write_u64(cgrp, cft, val); |
| 1991 | } else { |
KOSAKI Motohiro | 478988d | 2009-10-26 16:49:36 -0700 | [diff] [blame] | 1992 | s64 val = simple_strtoll(strstrip(buffer), &end, 0); |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 1993 | if (*end) |
| 1994 | return -EINVAL; |
| 1995 | retval = cft->write_s64(cgrp, cft, val); |
| 1996 | } |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1997 | if (!retval) |
| 1998 | retval = nbytes; |
| 1999 | return retval; |
| 2000 | } |
| 2001 | |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2002 | static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft, |
| 2003 | struct file *file, |
| 2004 | const char __user *userbuf, |
| 2005 | size_t nbytes, loff_t *unused_ppos) |
| 2006 | { |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 2007 | char local_buffer[CGROUP_LOCAL_BUFFER_SIZE]; |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2008 | int retval = 0; |
| 2009 | size_t max_bytes = cft->max_write_len; |
| 2010 | char *buffer = local_buffer; |
| 2011 | |
| 2012 | if (!max_bytes) |
| 2013 | max_bytes = sizeof(local_buffer) - 1; |
| 2014 | if (nbytes >= max_bytes) |
| 2015 | return -E2BIG; |
| 2016 | /* Allocate a dynamic buffer if we need one */ |
| 2017 | if (nbytes >= sizeof(local_buffer)) { |
| 2018 | buffer = kmalloc(nbytes + 1, GFP_KERNEL); |
| 2019 | if (buffer == NULL) |
| 2020 | return -ENOMEM; |
| 2021 | } |
Li Zefan | 5a3eb9f | 2008-07-29 22:33:18 -0700 | [diff] [blame] | 2022 | if (nbytes && copy_from_user(buffer, userbuf, nbytes)) { |
| 2023 | retval = -EFAULT; |
| 2024 | goto out; |
| 2025 | } |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2026 | |
| 2027 | buffer[nbytes] = 0; /* nul-terminate */ |
KOSAKI Motohiro | 478988d | 2009-10-26 16:49:36 -0700 | [diff] [blame] | 2028 | retval = cft->write_string(cgrp, cft, strstrip(buffer)); |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2029 | if (!retval) |
| 2030 | retval = nbytes; |
Li Zefan | 5a3eb9f | 2008-07-29 22:33:18 -0700 | [diff] [blame] | 2031 | out: |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2032 | if (buffer != local_buffer) |
| 2033 | kfree(buffer); |
| 2034 | return retval; |
| 2035 | } |
| 2036 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2037 | static ssize_t cgroup_file_write(struct file *file, const char __user *buf, |
| 2038 | size_t nbytes, loff_t *ppos) |
| 2039 | { |
| 2040 | struct cftype *cft = __d_cft(file->f_dentry); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2041 | struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2042 | |
Li Zefan | 75139b8 | 2009-01-07 18:07:33 -0800 | [diff] [blame] | 2043 | if (cgroup_is_removed(cgrp)) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2044 | return -ENODEV; |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 2045 | if (cft->write) |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2046 | return cft->write(cgrp, cft, file, buf, nbytes, ppos); |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 2047 | if (cft->write_u64 || cft->write_s64) |
| 2048 | return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos); |
Paul Menage | db3b149 | 2008-07-25 01:46:58 -0700 | [diff] [blame] | 2049 | if (cft->write_string) |
| 2050 | return cgroup_write_string(cgrp, cft, file, buf, nbytes, ppos); |
Pavel Emelyanov | d447ea2 | 2008-04-29 01:00:08 -0700 | [diff] [blame] | 2051 | if (cft->trigger) { |
| 2052 | int ret = cft->trigger(cgrp, (unsigned int)cft->private); |
| 2053 | return ret ? ret : nbytes; |
| 2054 | } |
Paul Menage | 355e0c4 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 2055 | return -EINVAL; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2056 | } |
| 2057 | |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 2058 | static ssize_t cgroup_read_u64(struct cgroup *cgrp, struct cftype *cft, |
| 2059 | struct file *file, |
| 2060 | char __user *buf, size_t nbytes, |
| 2061 | loff_t *ppos) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2062 | { |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 2063 | char tmp[CGROUP_LOCAL_BUFFER_SIZE]; |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 2064 | u64 val = cft->read_u64(cgrp, cft); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2065 | int len = sprintf(tmp, "%llu\n", (unsigned long long) val); |
| 2066 | |
| 2067 | return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); |
| 2068 | } |
| 2069 | |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 2070 | static ssize_t cgroup_read_s64(struct cgroup *cgrp, struct cftype *cft, |
| 2071 | struct file *file, |
| 2072 | char __user *buf, size_t nbytes, |
| 2073 | loff_t *ppos) |
| 2074 | { |
Paul Menage | 84eea84 | 2008-07-25 01:47:00 -0700 | [diff] [blame] | 2075 | char tmp[CGROUP_LOCAL_BUFFER_SIZE]; |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 2076 | s64 val = cft->read_s64(cgrp, cft); |
| 2077 | int len = sprintf(tmp, "%lld\n", (long long) val); |
| 2078 | |
| 2079 | return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); |
| 2080 | } |
| 2081 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2082 | static ssize_t cgroup_file_read(struct file *file, char __user *buf, |
| 2083 | size_t nbytes, loff_t *ppos) |
| 2084 | { |
| 2085 | struct cftype *cft = __d_cft(file->f_dentry); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2086 | struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2087 | |
Li Zefan | 75139b8 | 2009-01-07 18:07:33 -0800 | [diff] [blame] | 2088 | if (cgroup_is_removed(cgrp)) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2089 | return -ENODEV; |
| 2090 | |
| 2091 | if (cft->read) |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2092 | return cft->read(cgrp, cft, file, buf, nbytes, ppos); |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 2093 | if (cft->read_u64) |
| 2094 | return cgroup_read_u64(cgrp, cft, file, buf, nbytes, ppos); |
Paul Menage | e73d2c6 | 2008-04-29 01:00:06 -0700 | [diff] [blame] | 2095 | if (cft->read_s64) |
| 2096 | return cgroup_read_s64(cgrp, cft, file, buf, nbytes, ppos); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2097 | return -EINVAL; |
| 2098 | } |
| 2099 | |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2100 | /* |
| 2101 | * seqfile ops/methods for returning structured data. Currently just |
| 2102 | * supports string->u64 maps, but can be extended in future. |
| 2103 | */ |
| 2104 | |
| 2105 | struct cgroup_seqfile_state { |
| 2106 | struct cftype *cft; |
| 2107 | struct cgroup *cgroup; |
| 2108 | }; |
| 2109 | |
| 2110 | static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value) |
| 2111 | { |
| 2112 | struct seq_file *sf = cb->state; |
| 2113 | return seq_printf(sf, "%s %llu\n", key, (unsigned long long)value); |
| 2114 | } |
| 2115 | |
| 2116 | static int cgroup_seqfile_show(struct seq_file *m, void *arg) |
| 2117 | { |
| 2118 | struct cgroup_seqfile_state *state = m->private; |
| 2119 | struct cftype *cft = state->cft; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 2120 | if (cft->read_map) { |
| 2121 | struct cgroup_map_cb cb = { |
| 2122 | .fill = cgroup_map_add, |
| 2123 | .state = m, |
| 2124 | }; |
| 2125 | return cft->read_map(state->cgroup, cft, &cb); |
| 2126 | } |
| 2127 | return cft->read_seq_string(state->cgroup, cft, m); |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2128 | } |
| 2129 | |
Adrian Bunk | 96930a6 | 2008-07-25 19:46:21 -0700 | [diff] [blame] | 2130 | static int cgroup_seqfile_release(struct inode *inode, struct file *file) |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2131 | { |
| 2132 | struct seq_file *seq = file->private_data; |
| 2133 | kfree(seq->private); |
| 2134 | return single_release(inode, file); |
| 2135 | } |
| 2136 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 2137 | static const struct file_operations cgroup_seqfile_operations = { |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2138 | .read = seq_read, |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 2139 | .write = cgroup_file_write, |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2140 | .llseek = seq_lseek, |
| 2141 | .release = cgroup_seqfile_release, |
| 2142 | }; |
| 2143 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2144 | static int cgroup_file_open(struct inode *inode, struct file *file) |
| 2145 | { |
| 2146 | int err; |
| 2147 | struct cftype *cft; |
| 2148 | |
| 2149 | err = generic_file_open(inode, file); |
| 2150 | if (err) |
| 2151 | return err; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2152 | cft = __d_cft(file->f_dentry); |
Li Zefan | 75139b8 | 2009-01-07 18:07:33 -0800 | [diff] [blame] | 2153 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 2154 | if (cft->read_map || cft->read_seq_string) { |
Paul Menage | 9179656 | 2008-04-29 01:00:01 -0700 | [diff] [blame] | 2155 | struct cgroup_seqfile_state *state = |
| 2156 | kzalloc(sizeof(*state), GFP_USER); |
| 2157 | if (!state) |
| 2158 | return -ENOMEM; |
| 2159 | state->cft = cft; |
| 2160 | state->cgroup = __d_cgrp(file->f_dentry->d_parent); |
| 2161 | file->f_op = &cgroup_seqfile_operations; |
| 2162 | err = single_open(file, cgroup_seqfile_show, state); |
| 2163 | if (err < 0) |
| 2164 | kfree(state); |
| 2165 | } else if (cft->open) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2166 | err = cft->open(inode, file); |
| 2167 | else |
| 2168 | err = 0; |
| 2169 | |
| 2170 | return err; |
| 2171 | } |
| 2172 | |
| 2173 | static int cgroup_file_release(struct inode *inode, struct file *file) |
| 2174 | { |
| 2175 | struct cftype *cft = __d_cft(file->f_dentry); |
| 2176 | if (cft->release) |
| 2177 | return cft->release(inode, file); |
| 2178 | return 0; |
| 2179 | } |
| 2180 | |
| 2181 | /* |
| 2182 | * cgroup_rename - Only allow simple rename of directories in place. |
| 2183 | */ |
| 2184 | static int cgroup_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 2185 | struct inode *new_dir, struct dentry *new_dentry) |
| 2186 | { |
| 2187 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) |
| 2188 | return -ENOTDIR; |
| 2189 | if (new_dentry->d_inode) |
| 2190 | return -EEXIST; |
| 2191 | if (old_dir != new_dir) |
| 2192 | return -EIO; |
| 2193 | return simple_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 2194 | } |
| 2195 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 2196 | static const struct file_operations cgroup_file_operations = { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2197 | .read = cgroup_file_read, |
| 2198 | .write = cgroup_file_write, |
| 2199 | .llseek = generic_file_llseek, |
| 2200 | .open = cgroup_file_open, |
| 2201 | .release = cgroup_file_release, |
| 2202 | }; |
| 2203 | |
Alexey Dobriyan | 6e1d5dc | 2009-09-21 17:01:11 -0700 | [diff] [blame] | 2204 | static const struct inode_operations cgroup_dir_inode_operations = { |
Al Viro | c72a04e | 2011-01-14 05:31:45 +0000 | [diff] [blame] | 2205 | .lookup = cgroup_lookup, |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2206 | .mkdir = cgroup_mkdir, |
| 2207 | .rmdir = cgroup_rmdir, |
| 2208 | .rename = cgroup_rename, |
| 2209 | }; |
| 2210 | |
Al Viro | c72a04e | 2011-01-14 05:31:45 +0000 | [diff] [blame] | 2211 | static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) |
| 2212 | { |
| 2213 | if (dentry->d_name.len > NAME_MAX) |
| 2214 | return ERR_PTR(-ENAMETOOLONG); |
| 2215 | d_add(dentry, NULL); |
| 2216 | return NULL; |
| 2217 | } |
| 2218 | |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 2219 | /* |
| 2220 | * Check if a file is a control file |
| 2221 | */ |
| 2222 | static inline struct cftype *__file_cft(struct file *file) |
| 2223 | { |
| 2224 | if (file->f_dentry->d_inode->i_fop != &cgroup_file_operations) |
| 2225 | return ERR_PTR(-EINVAL); |
| 2226 | return __d_cft(file->f_dentry); |
| 2227 | } |
| 2228 | |
Nick Piggin | 5adcee1 | 2011-01-07 17:49:20 +1100 | [diff] [blame] | 2229 | static int cgroup_create_file(struct dentry *dentry, mode_t mode, |
| 2230 | struct super_block *sb) |
| 2231 | { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2232 | struct inode *inode; |
| 2233 | |
| 2234 | if (!dentry) |
| 2235 | return -ENOENT; |
| 2236 | if (dentry->d_inode) |
| 2237 | return -EEXIST; |
| 2238 | |
| 2239 | inode = cgroup_new_inode(mode, sb); |
| 2240 | if (!inode) |
| 2241 | return -ENOMEM; |
| 2242 | |
| 2243 | if (S_ISDIR(mode)) { |
| 2244 | inode->i_op = &cgroup_dir_inode_operations; |
| 2245 | inode->i_fop = &simple_dir_operations; |
| 2246 | |
| 2247 | /* start off with i_nlink == 2 (for "." entry) */ |
| 2248 | inc_nlink(inode); |
| 2249 | |
| 2250 | /* start with the directory inode held, so that we can |
| 2251 | * populate it without racing with another mkdir */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2252 | mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2253 | } else if (S_ISREG(mode)) { |
| 2254 | inode->i_size = 0; |
| 2255 | inode->i_fop = &cgroup_file_operations; |
| 2256 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2257 | d_instantiate(dentry, inode); |
| 2258 | dget(dentry); /* Extra count - pin the dentry in core */ |
| 2259 | return 0; |
| 2260 | } |
| 2261 | |
| 2262 | /* |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 2263 | * cgroup_create_dir - create a directory for an object. |
| 2264 | * @cgrp: the cgroup we create the directory for. It must have a valid |
| 2265 | * ->parent field. And we are going to fill its ->dentry field. |
| 2266 | * @dentry: dentry of the new cgroup |
| 2267 | * @mode: mode to set on new directory. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2268 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2269 | static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry, |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 2270 | mode_t mode) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2271 | { |
| 2272 | struct dentry *parent; |
| 2273 | int error = 0; |
| 2274 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2275 | parent = cgrp->parent->dentry; |
| 2276 | error = cgroup_create_file(dentry, S_IFDIR | mode, cgrp->root->sb); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2277 | if (!error) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2278 | dentry->d_fsdata = cgrp; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2279 | inc_nlink(parent->d_inode); |
Paul Menage | a47295e | 2009-01-07 18:07:44 -0800 | [diff] [blame] | 2280 | rcu_assign_pointer(cgrp->dentry, dentry); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2281 | dget(dentry); |
| 2282 | } |
| 2283 | dput(dentry); |
| 2284 | |
| 2285 | return error; |
| 2286 | } |
| 2287 | |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 2288 | /** |
| 2289 | * cgroup_file_mode - deduce file mode of a control file |
| 2290 | * @cft: the control file in question |
| 2291 | * |
| 2292 | * returns cft->mode if ->mode is not 0 |
| 2293 | * returns S_IRUGO|S_IWUSR if it has both a read and a write handler |
| 2294 | * returns S_IRUGO if it has only a read handler |
| 2295 | * returns S_IWUSR if it has only a write hander |
| 2296 | */ |
| 2297 | static mode_t cgroup_file_mode(const struct cftype *cft) |
| 2298 | { |
| 2299 | mode_t mode = 0; |
| 2300 | |
| 2301 | if (cft->mode) |
| 2302 | return cft->mode; |
| 2303 | |
| 2304 | if (cft->read || cft->read_u64 || cft->read_s64 || |
| 2305 | cft->read_map || cft->read_seq_string) |
| 2306 | mode |= S_IRUGO; |
| 2307 | |
| 2308 | if (cft->write || cft->write_u64 || cft->write_s64 || |
| 2309 | cft->write_string || cft->trigger) |
| 2310 | mode |= S_IWUSR; |
| 2311 | |
| 2312 | return mode; |
| 2313 | } |
| 2314 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2315 | int cgroup_add_file(struct cgroup *cgrp, |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2316 | struct cgroup_subsys *subsys, |
| 2317 | const struct cftype *cft) |
| 2318 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2319 | struct dentry *dir = cgrp->dentry; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2320 | struct dentry *dentry; |
| 2321 | int error; |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 2322 | mode_t mode; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2323 | |
| 2324 | char name[MAX_CGROUP_TYPE_NAMELEN + MAX_CFTYPE_NAME + 2] = { 0 }; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2325 | if (subsys && !test_bit(ROOT_NOPREFIX, &cgrp->root->flags)) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2326 | strcpy(name, subsys->name); |
| 2327 | strcat(name, "."); |
| 2328 | } |
| 2329 | strcat(name, cft->name); |
| 2330 | BUG_ON(!mutex_is_locked(&dir->d_inode->i_mutex)); |
| 2331 | dentry = lookup_one_len(name, dir, strlen(name)); |
| 2332 | if (!IS_ERR(dentry)) { |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 2333 | mode = cgroup_file_mode(cft); |
| 2334 | error = cgroup_create_file(dentry, mode | S_IFREG, |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2335 | cgrp->root->sb); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2336 | if (!error) |
| 2337 | dentry->d_fsdata = (void *)cft; |
| 2338 | dput(dentry); |
| 2339 | } else |
| 2340 | error = PTR_ERR(dentry); |
| 2341 | return error; |
| 2342 | } |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 2343 | EXPORT_SYMBOL_GPL(cgroup_add_file); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2344 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2345 | int cgroup_add_files(struct cgroup *cgrp, |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2346 | struct cgroup_subsys *subsys, |
| 2347 | const struct cftype cft[], |
| 2348 | int count) |
| 2349 | { |
| 2350 | int i, err; |
| 2351 | for (i = 0; i < count; i++) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2352 | err = cgroup_add_file(cgrp, subsys, &cft[i]); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2353 | if (err) |
| 2354 | return err; |
| 2355 | } |
| 2356 | return 0; |
| 2357 | } |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 2358 | EXPORT_SYMBOL_GPL(cgroup_add_files); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 2359 | |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 2360 | /** |
| 2361 | * cgroup_task_count - count the number of tasks in a cgroup. |
| 2362 | * @cgrp: the cgroup in question |
| 2363 | * |
| 2364 | * Return the number of tasks in the cgroup. |
| 2365 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2366 | int cgroup_task_count(const struct cgroup *cgrp) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2367 | { |
| 2368 | int count = 0; |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 2369 | struct cg_cgroup_link *link; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2370 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2371 | read_lock(&css_set_lock); |
KOSAKI Motohiro | 71cbb94 | 2008-07-25 01:46:55 -0700 | [diff] [blame] | 2372 | list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) { |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 2373 | count += atomic_read(&link->cg->refcount); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2374 | } |
| 2375 | read_unlock(&css_set_lock); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2376 | return count; |
| 2377 | } |
| 2378 | |
| 2379 | /* |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2380 | * Advance a list_head iterator. The iterator should be positioned at |
| 2381 | * the start of a css_set |
| 2382 | */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2383 | static void cgroup_advance_iter(struct cgroup *cgrp, |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 2384 | struct cgroup_iter *it) |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2385 | { |
| 2386 | struct list_head *l = it->cg_link; |
| 2387 | struct cg_cgroup_link *link; |
| 2388 | struct css_set *cg; |
| 2389 | |
| 2390 | /* Advance to the next non-empty css_set */ |
| 2391 | do { |
| 2392 | l = l->next; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2393 | if (l == &cgrp->css_sets) { |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2394 | it->cg_link = NULL; |
| 2395 | return; |
| 2396 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2397 | link = list_entry(l, struct cg_cgroup_link, cgrp_link_list); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2398 | cg = link->cg; |
| 2399 | } while (list_empty(&cg->tasks)); |
| 2400 | it->cg_link = l; |
| 2401 | it->task = cg->tasks.next; |
| 2402 | } |
| 2403 | |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2404 | /* |
| 2405 | * To reduce the fork() overhead for systems that are not actually |
| 2406 | * using their cgroups capability, we don't maintain the lists running |
| 2407 | * through each css_set to its tasks until we see the list actually |
| 2408 | * used - in other words after the first call to cgroup_iter_start(). |
| 2409 | * |
| 2410 | * The tasklist_lock is not held here, as do_each_thread() and |
| 2411 | * while_each_thread() are protected by RCU. |
| 2412 | */ |
Adrian Bunk | 3df91fe | 2008-04-29 00:59:54 -0700 | [diff] [blame] | 2413 | static void cgroup_enable_task_cg_lists(void) |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2414 | { |
| 2415 | struct task_struct *p, *g; |
| 2416 | write_lock(&css_set_lock); |
| 2417 | use_task_css_set_links = 1; |
| 2418 | do_each_thread(g, p) { |
| 2419 | task_lock(p); |
Li Zefan | 0e04388 | 2008-04-17 11:37:15 +0800 | [diff] [blame] | 2420 | /* |
| 2421 | * We should check if the process is exiting, otherwise |
| 2422 | * it will race with cgroup_exit() in that the list |
| 2423 | * entry won't be deleted though the process has exited. |
| 2424 | */ |
| 2425 | if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list)) |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2426 | list_add(&p->cg_list, &p->cgroups->tasks); |
| 2427 | task_unlock(p); |
| 2428 | } while_each_thread(g, p); |
| 2429 | write_unlock(&css_set_lock); |
| 2430 | } |
| 2431 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2432 | void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it) |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2433 | { |
| 2434 | /* |
| 2435 | * The first time anyone tries to iterate across a cgroup, |
| 2436 | * we need to enable the list linking each css_set to its |
| 2437 | * tasks, and fix up all existing tasks. |
| 2438 | */ |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2439 | if (!use_task_css_set_links) |
| 2440 | cgroup_enable_task_cg_lists(); |
| 2441 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2442 | read_lock(&css_set_lock); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2443 | it->cg_link = &cgrp->css_sets; |
| 2444 | cgroup_advance_iter(cgrp, it); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2445 | } |
| 2446 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2447 | struct task_struct *cgroup_iter_next(struct cgroup *cgrp, |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2448 | struct cgroup_iter *it) |
| 2449 | { |
| 2450 | struct task_struct *res; |
| 2451 | struct list_head *l = it->task; |
Lai Jiangshan | 2019f63 | 2009-01-07 18:07:36 -0800 | [diff] [blame] | 2452 | struct cg_cgroup_link *link; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2453 | |
| 2454 | /* If the iterator cg is NULL, we have no tasks */ |
| 2455 | if (!it->cg_link) |
| 2456 | return NULL; |
| 2457 | res = list_entry(l, struct task_struct, cg_list); |
| 2458 | /* Advance iterator to find next entry */ |
| 2459 | l = l->next; |
Lai Jiangshan | 2019f63 | 2009-01-07 18:07:36 -0800 | [diff] [blame] | 2460 | link = list_entry(it->cg_link, struct cg_cgroup_link, cgrp_link_list); |
| 2461 | if (l == &link->cg->tasks) { |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2462 | /* We reached the end of this task list - move on to |
| 2463 | * the next cg_cgroup_link */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2464 | cgroup_advance_iter(cgrp, it); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2465 | } else { |
| 2466 | it->task = l; |
| 2467 | } |
| 2468 | return res; |
| 2469 | } |
| 2470 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2471 | void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it) |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2472 | { |
| 2473 | read_unlock(&css_set_lock); |
| 2474 | } |
| 2475 | |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2476 | static inline int started_after_time(struct task_struct *t1, |
| 2477 | struct timespec *time, |
| 2478 | struct task_struct *t2) |
| 2479 | { |
| 2480 | int start_diff = timespec_compare(&t1->start_time, time); |
| 2481 | if (start_diff > 0) { |
| 2482 | return 1; |
| 2483 | } else if (start_diff < 0) { |
| 2484 | return 0; |
| 2485 | } else { |
| 2486 | /* |
| 2487 | * Arbitrarily, if two processes started at the same |
| 2488 | * time, we'll say that the lower pointer value |
| 2489 | * started first. Note that t2 may have exited by now |
| 2490 | * so this may not be a valid pointer any longer, but |
| 2491 | * that's fine - it still serves to distinguish |
| 2492 | * between two tasks started (effectively) simultaneously. |
| 2493 | */ |
| 2494 | return t1 > t2; |
| 2495 | } |
| 2496 | } |
| 2497 | |
| 2498 | /* |
| 2499 | * This function is a callback from heap_insert() and is used to order |
| 2500 | * the heap. |
| 2501 | * In this case we order the heap in descending task start time. |
| 2502 | */ |
| 2503 | static inline int started_after(void *p1, void *p2) |
| 2504 | { |
| 2505 | struct task_struct *t1 = p1; |
| 2506 | struct task_struct *t2 = p2; |
| 2507 | return started_after_time(t1, &t2->start_time, t2); |
| 2508 | } |
| 2509 | |
| 2510 | /** |
| 2511 | * cgroup_scan_tasks - iterate though all the tasks in a cgroup |
| 2512 | * @scan: struct cgroup_scanner containing arguments for the scan |
| 2513 | * |
| 2514 | * Arguments include pointers to callback functions test_task() and |
| 2515 | * process_task(). |
| 2516 | * Iterate through all the tasks in a cgroup, calling test_task() for each, |
| 2517 | * and if it returns true, call process_task() for it also. |
| 2518 | * The test_task pointer may be NULL, meaning always true (select all tasks). |
| 2519 | * Effectively duplicates cgroup_iter_{start,next,end}() |
| 2520 | * but does not lock css_set_lock for the call to process_task(). |
| 2521 | * The struct cgroup_scanner may be embedded in any structure of the caller's |
| 2522 | * creation. |
| 2523 | * It is guaranteed that process_task() will act on every task that |
| 2524 | * is a member of the cgroup for the duration of this call. This |
| 2525 | * function may or may not call process_task() for tasks that exit |
| 2526 | * or move to a different cgroup during the call, or are forked or |
| 2527 | * move into the cgroup during the call. |
| 2528 | * |
| 2529 | * Note that test_task() may be called with locks held, and may in some |
| 2530 | * situations be called multiple times for the same task, so it should |
| 2531 | * be cheap. |
| 2532 | * If the heap pointer in the struct cgroup_scanner is non-NULL, a heap has been |
| 2533 | * pre-allocated and will be used for heap operations (and its "gt" member will |
| 2534 | * be overwritten), else a temporary heap will be used (allocation of which |
| 2535 | * may cause this function to fail). |
| 2536 | */ |
| 2537 | int cgroup_scan_tasks(struct cgroup_scanner *scan) |
| 2538 | { |
| 2539 | int retval, i; |
| 2540 | struct cgroup_iter it; |
| 2541 | struct task_struct *p, *dropped; |
| 2542 | /* Never dereference latest_task, since it's not refcounted */ |
| 2543 | struct task_struct *latest_task = NULL; |
| 2544 | struct ptr_heap tmp_heap; |
| 2545 | struct ptr_heap *heap; |
| 2546 | struct timespec latest_time = { 0, 0 }; |
| 2547 | |
| 2548 | if (scan->heap) { |
| 2549 | /* The caller supplied our heap and pre-allocated its memory */ |
| 2550 | heap = scan->heap; |
| 2551 | heap->gt = &started_after; |
| 2552 | } else { |
| 2553 | /* We need to allocate our own heap memory */ |
| 2554 | heap = &tmp_heap; |
| 2555 | retval = heap_init(heap, PAGE_SIZE, GFP_KERNEL, &started_after); |
| 2556 | if (retval) |
| 2557 | /* cannot allocate the heap */ |
| 2558 | return retval; |
| 2559 | } |
| 2560 | |
| 2561 | again: |
| 2562 | /* |
| 2563 | * Scan tasks in the cgroup, using the scanner's "test_task" callback |
| 2564 | * to determine which are of interest, and using the scanner's |
| 2565 | * "process_task" callback to process any of them that need an update. |
| 2566 | * Since we don't want to hold any locks during the task updates, |
| 2567 | * gather tasks to be processed in a heap structure. |
| 2568 | * The heap is sorted by descending task start time. |
| 2569 | * If the statically-sized heap fills up, we overflow tasks that |
| 2570 | * started later, and in future iterations only consider tasks that |
| 2571 | * started after the latest task in the previous pass. This |
| 2572 | * guarantees forward progress and that we don't miss any tasks. |
| 2573 | */ |
| 2574 | heap->size = 0; |
| 2575 | cgroup_iter_start(scan->cg, &it); |
| 2576 | while ((p = cgroup_iter_next(scan->cg, &it))) { |
| 2577 | /* |
| 2578 | * Only affect tasks that qualify per the caller's callback, |
| 2579 | * if he provided one |
| 2580 | */ |
| 2581 | if (scan->test_task && !scan->test_task(p, scan)) |
| 2582 | continue; |
| 2583 | /* |
| 2584 | * Only process tasks that started after the last task |
| 2585 | * we processed |
| 2586 | */ |
| 2587 | if (!started_after_time(p, &latest_time, latest_task)) |
| 2588 | continue; |
| 2589 | dropped = heap_insert(heap, p); |
| 2590 | if (dropped == NULL) { |
| 2591 | /* |
| 2592 | * The new task was inserted; the heap wasn't |
| 2593 | * previously full |
| 2594 | */ |
| 2595 | get_task_struct(p); |
| 2596 | } else if (dropped != p) { |
| 2597 | /* |
| 2598 | * The new task was inserted, and pushed out a |
| 2599 | * different task |
| 2600 | */ |
| 2601 | get_task_struct(p); |
| 2602 | put_task_struct(dropped); |
| 2603 | } |
| 2604 | /* |
| 2605 | * Else the new task was newer than anything already in |
| 2606 | * the heap and wasn't inserted |
| 2607 | */ |
| 2608 | } |
| 2609 | cgroup_iter_end(scan->cg, &it); |
| 2610 | |
| 2611 | if (heap->size) { |
| 2612 | for (i = 0; i < heap->size; i++) { |
Paul Jackson | 4fe91d5 | 2008-04-29 00:59:55 -0700 | [diff] [blame] | 2613 | struct task_struct *q = heap->ptrs[i]; |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2614 | if (i == 0) { |
Paul Jackson | 4fe91d5 | 2008-04-29 00:59:55 -0700 | [diff] [blame] | 2615 | latest_time = q->start_time; |
| 2616 | latest_task = q; |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2617 | } |
| 2618 | /* Process the task per the caller's callback */ |
Paul Jackson | 4fe91d5 | 2008-04-29 00:59:55 -0700 | [diff] [blame] | 2619 | scan->process_task(q, scan); |
| 2620 | put_task_struct(q); |
Cliff Wickman | 31a7df0 | 2008-02-07 00:14:42 -0800 | [diff] [blame] | 2621 | } |
| 2622 | /* |
| 2623 | * If we had to process any tasks at all, scan again |
| 2624 | * in case some of them were in the middle of forking |
| 2625 | * children that didn't get processed. |
| 2626 | * Not the most efficient way to do it, but it avoids |
| 2627 | * having to take callback_mutex in the fork path |
| 2628 | */ |
| 2629 | goto again; |
| 2630 | } |
| 2631 | if (heap == &tmp_heap) |
| 2632 | heap_free(&tmp_heap); |
| 2633 | return 0; |
| 2634 | } |
| 2635 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2636 | /* |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2637 | * Stuff for reading the 'tasks'/'procs' files. |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2638 | * |
| 2639 | * Reading this file can return large amounts of data if a cgroup has |
| 2640 | * *lots* of attached tasks. So it may need several calls to read(), |
| 2641 | * but we cannot guarantee that the information we produce is correct |
| 2642 | * unless we produce it entirely atomically. |
| 2643 | * |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2644 | */ |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2645 | |
| 2646 | /* |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2647 | * The following two functions "fix" the issue where there are more pids |
| 2648 | * than kmalloc will give memory for; in such cases, we use vmalloc/vfree. |
| 2649 | * TODO: replace with a kernel-wide solution to this problem |
| 2650 | */ |
| 2651 | #define PIDLIST_TOO_LARGE(c) ((c) * sizeof(pid_t) > (PAGE_SIZE * 2)) |
| 2652 | static void *pidlist_allocate(int count) |
| 2653 | { |
| 2654 | if (PIDLIST_TOO_LARGE(count)) |
| 2655 | return vmalloc(count * sizeof(pid_t)); |
| 2656 | else |
| 2657 | return kmalloc(count * sizeof(pid_t), GFP_KERNEL); |
| 2658 | } |
| 2659 | static void pidlist_free(void *p) |
| 2660 | { |
| 2661 | if (is_vmalloc_addr(p)) |
| 2662 | vfree(p); |
| 2663 | else |
| 2664 | kfree(p); |
| 2665 | } |
| 2666 | static void *pidlist_resize(void *p, int newcount) |
| 2667 | { |
| 2668 | void *newlist; |
| 2669 | /* note: if new alloc fails, old p will still be valid either way */ |
| 2670 | if (is_vmalloc_addr(p)) { |
| 2671 | newlist = vmalloc(newcount * sizeof(pid_t)); |
| 2672 | if (!newlist) |
| 2673 | return NULL; |
| 2674 | memcpy(newlist, p, newcount * sizeof(pid_t)); |
| 2675 | vfree(p); |
| 2676 | } else { |
| 2677 | newlist = krealloc(p, newcount * sizeof(pid_t), GFP_KERNEL); |
| 2678 | } |
| 2679 | return newlist; |
| 2680 | } |
| 2681 | |
| 2682 | /* |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2683 | * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries |
| 2684 | * If the new stripped list is sufficiently smaller and there's enough memory |
| 2685 | * to allocate a new buffer, will let go of the unneeded memory. Returns the |
| 2686 | * number of unique elements. |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2687 | */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2688 | /* is the size difference enough that we should re-allocate the array? */ |
| 2689 | #define PIDLIST_REALLOC_DIFFERENCE(old, new) ((old) - PAGE_SIZE >= (new)) |
| 2690 | static int pidlist_uniq(pid_t **p, int length) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2691 | { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2692 | int src, dest = 1; |
| 2693 | pid_t *list = *p; |
| 2694 | pid_t *newlist; |
| 2695 | |
| 2696 | /* |
| 2697 | * we presume the 0th element is unique, so i starts at 1. trivial |
| 2698 | * edge cases first; no work needs to be done for either |
| 2699 | */ |
| 2700 | if (length == 0 || length == 1) |
| 2701 | return length; |
| 2702 | /* src and dest walk down the list; dest counts unique elements */ |
| 2703 | for (src = 1; src < length; src++) { |
| 2704 | /* find next unique element */ |
| 2705 | while (list[src] == list[src-1]) { |
| 2706 | src++; |
| 2707 | if (src == length) |
| 2708 | goto after; |
| 2709 | } |
| 2710 | /* dest always points to where the next unique element goes */ |
| 2711 | list[dest] = list[src]; |
| 2712 | dest++; |
| 2713 | } |
| 2714 | after: |
| 2715 | /* |
| 2716 | * if the length difference is large enough, we want to allocate a |
| 2717 | * smaller buffer to save memory. if this fails due to out of memory, |
| 2718 | * we'll just stay with what we've got. |
| 2719 | */ |
| 2720 | if (PIDLIST_REALLOC_DIFFERENCE(length, dest)) { |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2721 | newlist = pidlist_resize(list, dest); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2722 | if (newlist) |
| 2723 | *p = newlist; |
| 2724 | } |
| 2725 | return dest; |
| 2726 | } |
| 2727 | |
| 2728 | static int cmppid(const void *a, const void *b) |
| 2729 | { |
| 2730 | return *(pid_t *)a - *(pid_t *)b; |
| 2731 | } |
| 2732 | |
| 2733 | /* |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2734 | * find the appropriate pidlist for our purpose (given procs vs tasks) |
| 2735 | * returns with the lock on that pidlist already held, and takes care |
| 2736 | * of the use count, or returns NULL with no locks held if we're out of |
| 2737 | * memory. |
| 2738 | */ |
| 2739 | static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp, |
| 2740 | enum cgroup_filetype type) |
| 2741 | { |
| 2742 | struct cgroup_pidlist *l; |
| 2743 | /* don't need task_nsproxy() if we're looking at ourself */ |
Li Zefan | b70cc5f | 2010-03-10 15:22:12 -0800 | [diff] [blame] | 2744 | struct pid_namespace *ns = current->nsproxy->pid_ns; |
| 2745 | |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2746 | /* |
| 2747 | * We can't drop the pidlist_mutex before taking the l->mutex in case |
| 2748 | * the last ref-holder is trying to remove l from the list at the same |
| 2749 | * time. Holding the pidlist_mutex precludes somebody taking whichever |
| 2750 | * list we find out from under us - compare release_pid_array(). |
| 2751 | */ |
| 2752 | mutex_lock(&cgrp->pidlist_mutex); |
| 2753 | list_for_each_entry(l, &cgrp->pidlists, links) { |
| 2754 | if (l->key.type == type && l->key.ns == ns) { |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2755 | /* make sure l doesn't vanish out from under us */ |
| 2756 | down_write(&l->mutex); |
| 2757 | mutex_unlock(&cgrp->pidlist_mutex); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2758 | return l; |
| 2759 | } |
| 2760 | } |
| 2761 | /* entry not found; create a new one */ |
| 2762 | l = kmalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL); |
| 2763 | if (!l) { |
| 2764 | mutex_unlock(&cgrp->pidlist_mutex); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2765 | return l; |
| 2766 | } |
| 2767 | init_rwsem(&l->mutex); |
| 2768 | down_write(&l->mutex); |
| 2769 | l->key.type = type; |
Li Zefan | b70cc5f | 2010-03-10 15:22:12 -0800 | [diff] [blame] | 2770 | l->key.ns = get_pid_ns(ns); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2771 | l->use_count = 0; /* don't increment here */ |
| 2772 | l->list = NULL; |
| 2773 | l->owner = cgrp; |
| 2774 | list_add(&l->links, &cgrp->pidlists); |
| 2775 | mutex_unlock(&cgrp->pidlist_mutex); |
| 2776 | return l; |
| 2777 | } |
| 2778 | |
| 2779 | /* |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2780 | * Load a cgroup's pidarray with either procs' tgids or tasks' pids |
| 2781 | */ |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2782 | static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type, |
| 2783 | struct cgroup_pidlist **lp) |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2784 | { |
| 2785 | pid_t *array; |
| 2786 | int length; |
| 2787 | int pid, n = 0; /* used for populating the array */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2788 | struct cgroup_iter it; |
| 2789 | struct task_struct *tsk; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2790 | struct cgroup_pidlist *l; |
| 2791 | |
| 2792 | /* |
| 2793 | * If cgroup gets more users after we read count, we won't have |
| 2794 | * enough space - tough. This race is indistinguishable to the |
| 2795 | * caller from the case that the additional cgroup users didn't |
| 2796 | * show up until sometime later on. |
| 2797 | */ |
| 2798 | length = cgroup_task_count(cgrp); |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2799 | array = pidlist_allocate(length); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2800 | if (!array) |
| 2801 | return -ENOMEM; |
| 2802 | /* now, populate the array */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2803 | cgroup_iter_start(cgrp, &it); |
| 2804 | while ((tsk = cgroup_iter_next(cgrp, &it))) { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2805 | if (unlikely(n == length)) |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2806 | break; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2807 | /* get tgid or pid for procs or tasks file respectively */ |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2808 | if (type == CGROUP_FILE_PROCS) |
| 2809 | pid = task_tgid_vnr(tsk); |
| 2810 | else |
| 2811 | pid = task_pid_vnr(tsk); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2812 | if (pid > 0) /* make sure to only use valid results */ |
| 2813 | array[n++] = pid; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 2814 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2815 | cgroup_iter_end(cgrp, &it); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2816 | length = n; |
| 2817 | /* now sort & (if procs) strip out duplicates */ |
| 2818 | sort(array, length, sizeof(pid_t), cmppid, NULL); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2819 | if (type == CGROUP_FILE_PROCS) |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2820 | length = pidlist_uniq(&array, length); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2821 | l = cgroup_pidlist_find(cgrp, type); |
| 2822 | if (!l) { |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2823 | pidlist_free(array); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2824 | return -ENOMEM; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2825 | } |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2826 | /* store array, freeing old if necessary - lock already held */ |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2827 | pidlist_free(l->list); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2828 | l->list = array; |
| 2829 | l->length = length; |
| 2830 | l->use_count++; |
| 2831 | up_write(&l->mutex); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2832 | *lp = l; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2833 | return 0; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2834 | } |
| 2835 | |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2836 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 2837 | * cgroupstats_build - build and fill cgroupstats |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2838 | * @stats: cgroupstats to fill information into |
| 2839 | * @dentry: A dentry entry belonging to the cgroup for which stats have |
| 2840 | * been requested. |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 2841 | * |
| 2842 | * Build and fill cgroupstats so that taskstats can export it to user |
| 2843 | * space. |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2844 | */ |
| 2845 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) |
| 2846 | { |
| 2847 | int ret = -EINVAL; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2848 | struct cgroup *cgrp; |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2849 | struct cgroup_iter it; |
| 2850 | struct task_struct *tsk; |
Li Zefan | 33d283b | 2008-11-19 15:36:48 -0800 | [diff] [blame] | 2851 | |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2852 | /* |
Li Zefan | 33d283b | 2008-11-19 15:36:48 -0800 | [diff] [blame] | 2853 | * Validate dentry by checking the superblock operations, |
| 2854 | * and make sure it's a directory. |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2855 | */ |
Li Zefan | 33d283b | 2008-11-19 15:36:48 -0800 | [diff] [blame] | 2856 | if (dentry->d_sb->s_op != &cgroup_ops || |
| 2857 | !S_ISDIR(dentry->d_inode->i_mode)) |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2858 | goto err; |
| 2859 | |
| 2860 | ret = 0; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2861 | cgrp = dentry->d_fsdata; |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2862 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2863 | cgroup_iter_start(cgrp, &it); |
| 2864 | while ((tsk = cgroup_iter_next(cgrp, &it))) { |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2865 | switch (tsk->state) { |
| 2866 | case TASK_RUNNING: |
| 2867 | stats->nr_running++; |
| 2868 | break; |
| 2869 | case TASK_INTERRUPTIBLE: |
| 2870 | stats->nr_sleeping++; |
| 2871 | break; |
| 2872 | case TASK_UNINTERRUPTIBLE: |
| 2873 | stats->nr_uninterruptible++; |
| 2874 | break; |
| 2875 | case TASK_STOPPED: |
| 2876 | stats->nr_stopped++; |
| 2877 | break; |
| 2878 | default: |
| 2879 | if (delayacct_is_task_waiting_on_io(tsk)) |
| 2880 | stats->nr_io_wait++; |
| 2881 | break; |
| 2882 | } |
| 2883 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 2884 | cgroup_iter_end(cgrp, &it); |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2885 | |
Balbir Singh | 846c7bb | 2007-10-18 23:39:44 -0700 | [diff] [blame] | 2886 | err: |
| 2887 | return ret; |
| 2888 | } |
| 2889 | |
Paul Menage | 8f3ff20 | 2009-09-23 15:56:25 -0700 | [diff] [blame] | 2890 | |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2891 | /* |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2892 | * seq_file methods for the tasks/procs files. The seq_file position is the |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2893 | * next pid to display; the seq_file iterator is a pointer to the pid |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2894 | * in the cgroup->l->list array. |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2895 | */ |
| 2896 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2897 | static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2898 | { |
| 2899 | /* |
| 2900 | * Initially we receive a position value that corresponds to |
| 2901 | * one more than the last pid shown (or 0 on the first call or |
| 2902 | * after a seek to the start). Use a binary-search to find the |
| 2903 | * next pid to display, if any |
| 2904 | */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2905 | struct cgroup_pidlist *l = s->private; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2906 | int index = 0, pid = *pos; |
| 2907 | int *iter; |
| 2908 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2909 | down_read(&l->mutex); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2910 | if (pid) { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2911 | int end = l->length; |
Stephen Rothwell | 2077776 | 2008-10-21 16:11:20 +1100 | [diff] [blame] | 2912 | |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2913 | while (index < end) { |
| 2914 | int mid = (index + end) / 2; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2915 | if (l->list[mid] == pid) { |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2916 | index = mid; |
| 2917 | break; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2918 | } else if (l->list[mid] <= pid) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2919 | index = mid + 1; |
| 2920 | else |
| 2921 | end = mid; |
| 2922 | } |
| 2923 | } |
| 2924 | /* If we're off the end of the array, we're done */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2925 | if (index >= l->length) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2926 | return NULL; |
| 2927 | /* Update the abstract position to be the actual pid that we found */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2928 | iter = l->list + index; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2929 | *pos = *iter; |
| 2930 | return iter; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2931 | } |
| 2932 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2933 | static void cgroup_pidlist_stop(struct seq_file *s, void *v) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2934 | { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2935 | struct cgroup_pidlist *l = s->private; |
| 2936 | up_read(&l->mutex); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2937 | } |
| 2938 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2939 | static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2940 | { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2941 | struct cgroup_pidlist *l = s->private; |
| 2942 | pid_t *p = v; |
| 2943 | pid_t *end = l->list + l->length; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2944 | /* |
| 2945 | * Advance to the next pid in the array. If this goes off the |
| 2946 | * end, we're done |
| 2947 | */ |
| 2948 | p++; |
| 2949 | if (p >= end) { |
| 2950 | return NULL; |
| 2951 | } else { |
| 2952 | *pos = *p; |
| 2953 | return p; |
| 2954 | } |
| 2955 | } |
| 2956 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2957 | static int cgroup_pidlist_show(struct seq_file *s, void *v) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2958 | { |
| 2959 | return seq_printf(s, "%d\n", *(int *)v); |
| 2960 | } |
| 2961 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2962 | /* |
| 2963 | * seq_operations functions for iterating on pidlists through seq_file - |
| 2964 | * independent of whether it's tasks or procs |
| 2965 | */ |
| 2966 | static const struct seq_operations cgroup_pidlist_seq_operations = { |
| 2967 | .start = cgroup_pidlist_start, |
| 2968 | .stop = cgroup_pidlist_stop, |
| 2969 | .next = cgroup_pidlist_next, |
| 2970 | .show = cgroup_pidlist_show, |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2971 | }; |
| 2972 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2973 | static void cgroup_release_pid_array(struct cgroup_pidlist *l) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2974 | { |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2975 | /* |
| 2976 | * the case where we're the last user of this particular pidlist will |
| 2977 | * have us remove it from the cgroup's list, which entails taking the |
| 2978 | * mutex. since in pidlist_find the pidlist->lock depends on cgroup-> |
| 2979 | * pidlist_mutex, we have to take pidlist_mutex first. |
| 2980 | */ |
| 2981 | mutex_lock(&l->owner->pidlist_mutex); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2982 | down_write(&l->mutex); |
| 2983 | BUG_ON(!l->use_count); |
| 2984 | if (!--l->use_count) { |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2985 | /* we're the last user if refcount is 0; remove and free */ |
| 2986 | list_del(&l->links); |
| 2987 | mutex_unlock(&l->owner->pidlist_mutex); |
Ben Blum | d1d9fd3 | 2009-09-23 15:56:28 -0700 | [diff] [blame] | 2988 | pidlist_free(l->list); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2989 | put_pid_ns(l->key.ns); |
| 2990 | up_write(&l->mutex); |
| 2991 | kfree(l); |
| 2992 | return; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2993 | } |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 2994 | mutex_unlock(&l->owner->pidlist_mutex); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2995 | up_write(&l->mutex); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 2996 | } |
| 2997 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 2998 | static int cgroup_pidlist_release(struct inode *inode, struct file *file) |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 2999 | { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3000 | struct cgroup_pidlist *l; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3001 | if (!(file->f_mode & FMODE_READ)) |
| 3002 | return 0; |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3003 | /* |
| 3004 | * the seq_file will only be initialized if the file was opened for |
| 3005 | * reading; hence we check if it's not null only in that case. |
| 3006 | */ |
| 3007 | l = ((struct seq_file *)file->private_data)->private; |
| 3008 | cgroup_release_pid_array(l); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3009 | return seq_release(inode, file); |
| 3010 | } |
| 3011 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3012 | static const struct file_operations cgroup_pidlist_operations = { |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3013 | .read = seq_read, |
| 3014 | .llseek = seq_lseek, |
| 3015 | .write = cgroup_file_write, |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3016 | .release = cgroup_pidlist_release, |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3017 | }; |
| 3018 | |
| 3019 | /* |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3020 | * The following functions handle opens on a file that displays a pidlist |
| 3021 | * (tasks or procs). Prepare an array of the process/thread IDs of whoever's |
| 3022 | * in the cgroup. |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3023 | */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3024 | /* helper function for the two below it */ |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 3025 | static int cgroup_pidlist_open(struct file *file, enum cgroup_filetype type) |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3026 | { |
| 3027 | struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent); |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 3028 | struct cgroup_pidlist *l; |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3029 | int retval; |
| 3030 | |
| 3031 | /* Nothing to do for write-only files */ |
| 3032 | if (!(file->f_mode & FMODE_READ)) |
| 3033 | return 0; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3034 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3035 | /* have the array populated */ |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 3036 | retval = pidlist_array_load(cgrp, type, &l); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3037 | if (retval) |
| 3038 | return retval; |
| 3039 | /* configure file information */ |
| 3040 | file->f_op = &cgroup_pidlist_operations; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3041 | |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3042 | retval = seq_open(file, &cgroup_pidlist_seq_operations); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3043 | if (retval) { |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3044 | cgroup_release_pid_array(l); |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3045 | return retval; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3046 | } |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3047 | ((struct seq_file *)file->private_data)->private = l; |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3048 | return 0; |
| 3049 | } |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3050 | static int cgroup_tasks_open(struct inode *unused, struct file *file) |
| 3051 | { |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 3052 | return cgroup_pidlist_open(file, CGROUP_FILE_TASKS); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3053 | } |
| 3054 | static int cgroup_procs_open(struct inode *unused, struct file *file) |
| 3055 | { |
Ben Blum | 72a8cb3 | 2009-09-23 15:56:27 -0700 | [diff] [blame] | 3056 | return cgroup_pidlist_open(file, CGROUP_FILE_PROCS); |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3057 | } |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3058 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3059 | static u64 cgroup_read_notify_on_release(struct cgroup *cgrp, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3060 | struct cftype *cft) |
| 3061 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3062 | return notify_on_release(cgrp); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3063 | } |
| 3064 | |
Paul Menage | 6379c10 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 3065 | static int cgroup_write_notify_on_release(struct cgroup *cgrp, |
| 3066 | struct cftype *cft, |
| 3067 | u64 val) |
| 3068 | { |
| 3069 | clear_bit(CGRP_RELEASABLE, &cgrp->flags); |
| 3070 | if (val) |
| 3071 | set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); |
| 3072 | else |
| 3073 | clear_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); |
| 3074 | return 0; |
| 3075 | } |
| 3076 | |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3077 | /* |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3078 | * Unregister event and free resources. |
| 3079 | * |
| 3080 | * Gets called from workqueue. |
| 3081 | */ |
| 3082 | static void cgroup_event_remove(struct work_struct *work) |
| 3083 | { |
| 3084 | struct cgroup_event *event = container_of(work, struct cgroup_event, |
| 3085 | remove); |
| 3086 | struct cgroup *cgrp = event->cgrp; |
| 3087 | |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3088 | event->cft->unregister_event(cgrp, event->cft, event->eventfd); |
| 3089 | |
| 3090 | eventfd_ctx_put(event->eventfd); |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3091 | kfree(event); |
Kirill A. Shutemov | a0a4db5 | 2010-03-10 15:22:34 -0800 | [diff] [blame] | 3092 | dput(cgrp->dentry); |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3093 | } |
| 3094 | |
| 3095 | /* |
| 3096 | * Gets called on POLLHUP on eventfd when user closes it. |
| 3097 | * |
| 3098 | * Called with wqh->lock held and interrupts disabled. |
| 3099 | */ |
| 3100 | static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, |
| 3101 | int sync, void *key) |
| 3102 | { |
| 3103 | struct cgroup_event *event = container_of(wait, |
| 3104 | struct cgroup_event, wait); |
| 3105 | struct cgroup *cgrp = event->cgrp; |
| 3106 | unsigned long flags = (unsigned long)key; |
| 3107 | |
| 3108 | if (flags & POLLHUP) { |
Changli Gao | a93d2f1 | 2010-05-07 14:33:26 +0800 | [diff] [blame] | 3109 | __remove_wait_queue(event->wqh, &event->wait); |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3110 | spin_lock(&cgrp->event_list_lock); |
| 3111 | list_del(&event->list); |
| 3112 | spin_unlock(&cgrp->event_list_lock); |
| 3113 | /* |
| 3114 | * We are in atomic context, but cgroup_event_remove() may |
| 3115 | * sleep, so we have to call it in workqueue. |
| 3116 | */ |
| 3117 | schedule_work(&event->remove); |
| 3118 | } |
| 3119 | |
| 3120 | return 0; |
| 3121 | } |
| 3122 | |
| 3123 | static void cgroup_event_ptable_queue_proc(struct file *file, |
| 3124 | wait_queue_head_t *wqh, poll_table *pt) |
| 3125 | { |
| 3126 | struct cgroup_event *event = container_of(pt, |
| 3127 | struct cgroup_event, pt); |
| 3128 | |
| 3129 | event->wqh = wqh; |
| 3130 | add_wait_queue(wqh, &event->wait); |
| 3131 | } |
| 3132 | |
| 3133 | /* |
| 3134 | * Parse input and register new cgroup event handler. |
| 3135 | * |
| 3136 | * Input must be in format '<event_fd> <control_fd> <args>'. |
| 3137 | * Interpretation of args is defined by control file implementation. |
| 3138 | */ |
| 3139 | static int cgroup_write_event_control(struct cgroup *cgrp, struct cftype *cft, |
| 3140 | const char *buffer) |
| 3141 | { |
| 3142 | struct cgroup_event *event = NULL; |
| 3143 | unsigned int efd, cfd; |
| 3144 | struct file *efile = NULL; |
| 3145 | struct file *cfile = NULL; |
| 3146 | char *endp; |
| 3147 | int ret; |
| 3148 | |
| 3149 | efd = simple_strtoul(buffer, &endp, 10); |
| 3150 | if (*endp != ' ') |
| 3151 | return -EINVAL; |
| 3152 | buffer = endp + 1; |
| 3153 | |
| 3154 | cfd = simple_strtoul(buffer, &endp, 10); |
| 3155 | if ((*endp != ' ') && (*endp != '\0')) |
| 3156 | return -EINVAL; |
| 3157 | buffer = endp + 1; |
| 3158 | |
| 3159 | event = kzalloc(sizeof(*event), GFP_KERNEL); |
| 3160 | if (!event) |
| 3161 | return -ENOMEM; |
| 3162 | event->cgrp = cgrp; |
| 3163 | INIT_LIST_HEAD(&event->list); |
| 3164 | init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc); |
| 3165 | init_waitqueue_func_entry(&event->wait, cgroup_event_wake); |
| 3166 | INIT_WORK(&event->remove, cgroup_event_remove); |
| 3167 | |
| 3168 | efile = eventfd_fget(efd); |
| 3169 | if (IS_ERR(efile)) { |
| 3170 | ret = PTR_ERR(efile); |
| 3171 | goto fail; |
| 3172 | } |
| 3173 | |
| 3174 | event->eventfd = eventfd_ctx_fileget(efile); |
| 3175 | if (IS_ERR(event->eventfd)) { |
| 3176 | ret = PTR_ERR(event->eventfd); |
| 3177 | goto fail; |
| 3178 | } |
| 3179 | |
| 3180 | cfile = fget(cfd); |
| 3181 | if (!cfile) { |
| 3182 | ret = -EBADF; |
| 3183 | goto fail; |
| 3184 | } |
| 3185 | |
| 3186 | /* the process need read permission on control file */ |
| 3187 | ret = file_permission(cfile, MAY_READ); |
| 3188 | if (ret < 0) |
| 3189 | goto fail; |
| 3190 | |
| 3191 | event->cft = __file_cft(cfile); |
| 3192 | if (IS_ERR(event->cft)) { |
| 3193 | ret = PTR_ERR(event->cft); |
| 3194 | goto fail; |
| 3195 | } |
| 3196 | |
| 3197 | if (!event->cft->register_event || !event->cft->unregister_event) { |
| 3198 | ret = -EINVAL; |
| 3199 | goto fail; |
| 3200 | } |
| 3201 | |
| 3202 | ret = event->cft->register_event(cgrp, event->cft, |
| 3203 | event->eventfd, buffer); |
| 3204 | if (ret) |
| 3205 | goto fail; |
| 3206 | |
| 3207 | if (efile->f_op->poll(efile, &event->pt) & POLLHUP) { |
| 3208 | event->cft->unregister_event(cgrp, event->cft, event->eventfd); |
| 3209 | ret = 0; |
| 3210 | goto fail; |
| 3211 | } |
| 3212 | |
Kirill A. Shutemov | a0a4db5 | 2010-03-10 15:22:34 -0800 | [diff] [blame] | 3213 | /* |
| 3214 | * Events should be removed after rmdir of cgroup directory, but before |
| 3215 | * destroying subsystem state objects. Let's take reference to cgroup |
| 3216 | * directory dentry to do that. |
| 3217 | */ |
| 3218 | dget(cgrp->dentry); |
| 3219 | |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3220 | spin_lock(&cgrp->event_list_lock); |
| 3221 | list_add(&event->list, &cgrp->event_list); |
| 3222 | spin_unlock(&cgrp->event_list_lock); |
| 3223 | |
| 3224 | fput(cfile); |
| 3225 | fput(efile); |
| 3226 | |
| 3227 | return 0; |
| 3228 | |
| 3229 | fail: |
| 3230 | if (cfile) |
| 3231 | fput(cfile); |
| 3232 | |
| 3233 | if (event && event->eventfd && !IS_ERR(event->eventfd)) |
| 3234 | eventfd_ctx_put(event->eventfd); |
| 3235 | |
| 3236 | if (!IS_ERR_OR_NULL(efile)) |
| 3237 | fput(efile); |
| 3238 | |
| 3239 | kfree(event); |
| 3240 | |
| 3241 | return ret; |
| 3242 | } |
| 3243 | |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 3244 | static u64 cgroup_clone_children_read(struct cgroup *cgrp, |
| 3245 | struct cftype *cft) |
| 3246 | { |
| 3247 | return clone_children(cgrp); |
| 3248 | } |
| 3249 | |
| 3250 | static int cgroup_clone_children_write(struct cgroup *cgrp, |
| 3251 | struct cftype *cft, |
| 3252 | u64 val) |
| 3253 | { |
| 3254 | if (val) |
| 3255 | set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); |
| 3256 | else |
| 3257 | clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); |
| 3258 | return 0; |
| 3259 | } |
| 3260 | |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3261 | /* |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3262 | * for the common functions, 'private' gives the type of file |
| 3263 | */ |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3264 | /* for hysterical raisins, we can't put this on the older files */ |
| 3265 | #define CGROUP_FILE_GENERIC_PREFIX "cgroup." |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3266 | static struct cftype files[] = { |
| 3267 | { |
| 3268 | .name = "tasks", |
| 3269 | .open = cgroup_tasks_open, |
Paul Menage | af35102 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 3270 | .write_u64 = cgroup_tasks_write, |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3271 | .release = cgroup_pidlist_release, |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 3272 | .mode = S_IRUGO | S_IWUSR, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3273 | }, |
Ben Blum | 102a775 | 2009-09-23 15:56:26 -0700 | [diff] [blame] | 3274 | { |
| 3275 | .name = CGROUP_FILE_GENERIC_PREFIX "procs", |
| 3276 | .open = cgroup_procs_open, |
| 3277 | /* .write_u64 = cgroup_procs_write, TODO */ |
| 3278 | .release = cgroup_pidlist_release, |
| 3279 | .mode = S_IRUGO, |
| 3280 | }, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3281 | { |
| 3282 | .name = "notify_on_release", |
Paul Menage | f4c753b | 2008-04-29 00:59:56 -0700 | [diff] [blame] | 3283 | .read_u64 = cgroup_read_notify_on_release, |
Paul Menage | 6379c10 | 2008-07-25 01:47:01 -0700 | [diff] [blame] | 3284 | .write_u64 = cgroup_write_notify_on_release, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3285 | }, |
Kirill A. Shutemov | 0dea116 | 2010-03-10 15:22:20 -0800 | [diff] [blame] | 3286 | { |
| 3287 | .name = CGROUP_FILE_GENERIC_PREFIX "event_control", |
| 3288 | .write_string = cgroup_write_event_control, |
| 3289 | .mode = S_IWUGO, |
| 3290 | }, |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 3291 | { |
| 3292 | .name = "cgroup.clone_children", |
| 3293 | .read_u64 = cgroup_clone_children_read, |
| 3294 | .write_u64 = cgroup_clone_children_write, |
| 3295 | }, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3296 | }; |
| 3297 | |
| 3298 | static struct cftype cft_release_agent = { |
| 3299 | .name = "release_agent", |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 3300 | .read_seq_string = cgroup_release_agent_show, |
| 3301 | .write_string = cgroup_release_agent_write, |
| 3302 | .max_write_len = PATH_MAX, |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3303 | }; |
| 3304 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3305 | static int cgroup_populate_dir(struct cgroup *cgrp) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3306 | { |
| 3307 | int err; |
| 3308 | struct cgroup_subsys *ss; |
| 3309 | |
| 3310 | /* First clear out any existing files */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3311 | cgroup_clear_directory(cgrp->dentry); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3312 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3313 | err = cgroup_add_files(cgrp, NULL, files, ARRAY_SIZE(files)); |
Paul Menage | bbcb81d | 2007-10-18 23:39:32 -0700 | [diff] [blame] | 3314 | if (err < 0) |
| 3315 | return err; |
| 3316 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3317 | if (cgrp == cgrp->top_cgroup) { |
| 3318 | if ((err = cgroup_add_file(cgrp, NULL, &cft_release_agent)) < 0) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3319 | return err; |
| 3320 | } |
| 3321 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3322 | for_each_subsys(cgrp->root, ss) { |
| 3323 | if (ss->populate && (err = ss->populate(ss, cgrp)) < 0) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3324 | return err; |
| 3325 | } |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 3326 | /* This cgroup is ready now */ |
| 3327 | for_each_subsys(cgrp->root, ss) { |
| 3328 | struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; |
| 3329 | /* |
| 3330 | * Update id->css pointer and make this css visible from |
| 3331 | * CSS ID functions. This pointer will be dereferened |
| 3332 | * from RCU-read-side without locks. |
| 3333 | */ |
| 3334 | if (css->id) |
| 3335 | rcu_assign_pointer(css->id->css, css); |
| 3336 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3337 | |
| 3338 | return 0; |
| 3339 | } |
| 3340 | |
| 3341 | static void init_cgroup_css(struct cgroup_subsys_state *css, |
| 3342 | struct cgroup_subsys *ss, |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3343 | struct cgroup *cgrp) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3344 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3345 | css->cgroup = cgrp; |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3346 | atomic_set(&css->refcnt, 1); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3347 | css->flags = 0; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 3348 | css->id = NULL; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3349 | if (cgrp == dummytop) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3350 | set_bit(CSS_ROOT, &css->flags); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3351 | BUG_ON(cgrp->subsys[ss->subsys_id]); |
| 3352 | cgrp->subsys[ss->subsys_id] = css; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3353 | } |
| 3354 | |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3355 | static void cgroup_lock_hierarchy(struct cgroupfs_root *root) |
| 3356 | { |
| 3357 | /* We need to take each hierarchy_mutex in a consistent order */ |
| 3358 | int i; |
| 3359 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3360 | /* |
| 3361 | * No worry about a race with rebind_subsystems that might mess up the |
| 3362 | * locking order, since both parties are under cgroup_mutex. |
| 3363 | */ |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3364 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 3365 | struct cgroup_subsys *ss = subsys[i]; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3366 | if (ss == NULL) |
| 3367 | continue; |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3368 | if (ss->root == root) |
Li Zefan | cfebe56 | 2009-02-11 13:04:36 -0800 | [diff] [blame] | 3369 | mutex_lock(&ss->hierarchy_mutex); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3370 | } |
| 3371 | } |
| 3372 | |
| 3373 | static void cgroup_unlock_hierarchy(struct cgroupfs_root *root) |
| 3374 | { |
| 3375 | int i; |
| 3376 | |
| 3377 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 3378 | struct cgroup_subsys *ss = subsys[i]; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3379 | if (ss == NULL) |
| 3380 | continue; |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3381 | if (ss->root == root) |
| 3382 | mutex_unlock(&ss->hierarchy_mutex); |
| 3383 | } |
| 3384 | } |
| 3385 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3386 | /* |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3387 | * cgroup_create - create a cgroup |
| 3388 | * @parent: cgroup that will be parent of the new cgroup |
| 3389 | * @dentry: dentry of the new cgroup |
| 3390 | * @mode: mode to set on new inode |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3391 | * |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3392 | * Must be called with the mutex on the parent inode held |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3393 | */ |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3394 | static long cgroup_create(struct cgroup *parent, struct dentry *dentry, |
Li Zefan | 099fca3 | 2009-04-02 16:57:29 -0700 | [diff] [blame] | 3395 | mode_t mode) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3396 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3397 | struct cgroup *cgrp; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3398 | struct cgroupfs_root *root = parent->root; |
| 3399 | int err = 0; |
| 3400 | struct cgroup_subsys *ss; |
| 3401 | struct super_block *sb = root->sb; |
| 3402 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3403 | cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL); |
| 3404 | if (!cgrp) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3405 | return -ENOMEM; |
| 3406 | |
| 3407 | /* Grab a reference on the superblock so the hierarchy doesn't |
| 3408 | * get deleted on unmount if there are child cgroups. This |
| 3409 | * can be done outside cgroup_mutex, since the sb can't |
| 3410 | * disappear while someone has an open control file on the |
| 3411 | * fs */ |
| 3412 | atomic_inc(&sb->s_active); |
| 3413 | |
| 3414 | mutex_lock(&cgroup_mutex); |
| 3415 | |
Paul Menage | cc31edc | 2008-10-18 20:28:04 -0700 | [diff] [blame] | 3416 | init_cgroup_housekeeping(cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3417 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3418 | cgrp->parent = parent; |
| 3419 | cgrp->root = parent->root; |
| 3420 | cgrp->top_cgroup = parent->top_cgroup; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3421 | |
Li Zefan | b6abdb0 | 2008-03-04 14:28:19 -0800 | [diff] [blame] | 3422 | if (notify_on_release(parent)) |
| 3423 | set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags); |
| 3424 | |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 3425 | if (clone_children(parent)) |
| 3426 | set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags); |
| 3427 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3428 | for_each_subsys(root, ss) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3429 | struct cgroup_subsys_state *css = ss->create(ss, cgrp); |
Li Zefan | 4528fd0 | 2010-02-02 13:44:10 -0800 | [diff] [blame] | 3430 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3431 | if (IS_ERR(css)) { |
| 3432 | err = PTR_ERR(css); |
| 3433 | goto err_destroy; |
| 3434 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3435 | init_cgroup_css(css, ss, cgrp); |
Li Zefan | 4528fd0 | 2010-02-02 13:44:10 -0800 | [diff] [blame] | 3436 | if (ss->use_id) { |
| 3437 | err = alloc_css_id(ss, parent, cgrp); |
| 3438 | if (err) |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 3439 | goto err_destroy; |
Li Zefan | 4528fd0 | 2010-02-02 13:44:10 -0800 | [diff] [blame] | 3440 | } |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 3441 | /* At error, ->destroy() callback has to free assigned ID. */ |
Daniel Lezcano | 97978e6 | 2010-10-27 15:33:35 -0700 | [diff] [blame] | 3442 | if (clone_children(parent) && ss->post_clone) |
| 3443 | ss->post_clone(ss, cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3444 | } |
| 3445 | |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3446 | cgroup_lock_hierarchy(root); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3447 | list_add(&cgrp->sibling, &cgrp->parent->children); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3448 | cgroup_unlock_hierarchy(root); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3449 | root->number_of_cgroups++; |
| 3450 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3451 | err = cgroup_create_dir(cgrp, dentry, mode); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3452 | if (err < 0) |
| 3453 | goto err_remove; |
| 3454 | |
| 3455 | /* The cgroup directory was pre-locked for us */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3456 | BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex)); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3457 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3458 | err = cgroup_populate_dir(cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3459 | /* If err < 0, we have a half-filled directory - oh well ;) */ |
| 3460 | |
| 3461 | mutex_unlock(&cgroup_mutex); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3462 | mutex_unlock(&cgrp->dentry->d_inode->i_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3463 | |
| 3464 | return 0; |
| 3465 | |
| 3466 | err_remove: |
| 3467 | |
KAMEZAWA Hiroyuki | baef99a | 2009-01-29 14:25:10 -0800 | [diff] [blame] | 3468 | cgroup_lock_hierarchy(root); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3469 | list_del(&cgrp->sibling); |
KAMEZAWA Hiroyuki | baef99a | 2009-01-29 14:25:10 -0800 | [diff] [blame] | 3470 | cgroup_unlock_hierarchy(root); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3471 | root->number_of_cgroups--; |
| 3472 | |
| 3473 | err_destroy: |
| 3474 | |
| 3475 | for_each_subsys(root, ss) { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3476 | if (cgrp->subsys[ss->subsys_id]) |
| 3477 | ss->destroy(ss, cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3478 | } |
| 3479 | |
| 3480 | mutex_unlock(&cgroup_mutex); |
| 3481 | |
| 3482 | /* Release the reference count that we took on the superblock */ |
| 3483 | deactivate_super(sb); |
| 3484 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3485 | kfree(cgrp); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3486 | return err; |
| 3487 | } |
| 3488 | |
| 3489 | static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| 3490 | { |
| 3491 | struct cgroup *c_parent = dentry->d_parent->d_fsdata; |
| 3492 | |
| 3493 | /* the vfs holds inode->i_mutex already */ |
| 3494 | return cgroup_create(c_parent, dentry, mode | S_IFDIR); |
| 3495 | } |
| 3496 | |
Li Zefan | 55b6fd0 | 2008-07-29 22:33:20 -0700 | [diff] [blame] | 3497 | static int cgroup_has_css_refs(struct cgroup *cgrp) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3498 | { |
| 3499 | /* Check the reference count on each subsystem. Since we |
| 3500 | * already established that there are no tasks in the |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3501 | * cgroup, if the css refcount is also 1, then there should |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3502 | * be no outstanding references, so the subsystem is safe to |
| 3503 | * destroy. We scan across all subsystems rather than using |
| 3504 | * the per-hierarchy linked list of mounted subsystems since |
| 3505 | * we can be called via check_for_release() with no |
| 3506 | * synchronization other than RCU, and the subsystem linked |
| 3507 | * list isn't RCU-safe */ |
| 3508 | int i; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3509 | /* |
| 3510 | * We won't need to lock the subsys array, because the subsystems |
| 3511 | * we're concerned about aren't going anywhere since our cgroup root |
| 3512 | * has a reference on them. |
| 3513 | */ |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3514 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 3515 | struct cgroup_subsys *ss = subsys[i]; |
| 3516 | struct cgroup_subsys_state *css; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3517 | /* Skip subsystems not present or not in this hierarchy */ |
| 3518 | if (ss == NULL || ss->root != cgrp->root) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3519 | continue; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3520 | css = cgrp->subsys[ss->subsys_id]; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3521 | /* When called from check_for_release() it's possible |
| 3522 | * that by this point the cgroup has been removed |
| 3523 | * and the css deleted. But a false-positive doesn't |
| 3524 | * matter, since it can only happen if the cgroup |
| 3525 | * has been deleted and hence no longer needs the |
| 3526 | * release agent to be called anyway. */ |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3527 | if (css && (atomic_read(&css->refcnt) > 1)) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3528 | return 1; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3529 | } |
| 3530 | return 0; |
| 3531 | } |
| 3532 | |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3533 | /* |
| 3534 | * Atomically mark all (or else none) of the cgroup's CSS objects as |
| 3535 | * CSS_REMOVED. Return true on success, or false if the cgroup has |
| 3536 | * busy subsystems. Call with cgroup_mutex held |
| 3537 | */ |
| 3538 | |
| 3539 | static int cgroup_clear_css_refs(struct cgroup *cgrp) |
| 3540 | { |
| 3541 | struct cgroup_subsys *ss; |
| 3542 | unsigned long flags; |
| 3543 | bool failed = false; |
| 3544 | local_irq_save(flags); |
| 3545 | for_each_subsys(cgrp->root, ss) { |
| 3546 | struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; |
| 3547 | int refcnt; |
Paul Menage | 804b3c2 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 3548 | while (1) { |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3549 | /* We can only remove a CSS with a refcnt==1 */ |
| 3550 | refcnt = atomic_read(&css->refcnt); |
| 3551 | if (refcnt > 1) { |
| 3552 | failed = true; |
| 3553 | goto done; |
| 3554 | } |
| 3555 | BUG_ON(!refcnt); |
| 3556 | /* |
| 3557 | * Drop the refcnt to 0 while we check other |
| 3558 | * subsystems. This will cause any racing |
| 3559 | * css_tryget() to spin until we set the |
| 3560 | * CSS_REMOVED bits or abort |
| 3561 | */ |
Paul Menage | 804b3c2 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 3562 | if (atomic_cmpxchg(&css->refcnt, refcnt, 0) == refcnt) |
| 3563 | break; |
| 3564 | cpu_relax(); |
| 3565 | } |
Paul Menage | e7c5ec9 | 2009-01-07 18:08:38 -0800 | [diff] [blame] | 3566 | } |
| 3567 | done: |
| 3568 | for_each_subsys(cgrp->root, ss) { |
| 3569 | struct cgroup_subsys_state *css = cgrp->subsys[ss->subsys_id]; |
| 3570 | if (failed) { |
| 3571 | /* |
| 3572 | * Restore old refcnt if we previously managed |
| 3573 | * to clear it from 1 to 0 |
| 3574 | */ |
| 3575 | if (!atomic_read(&css->refcnt)) |
| 3576 | atomic_set(&css->refcnt, 1); |
| 3577 | } else { |
| 3578 | /* Commit the fact that the CSS is removed */ |
| 3579 | set_bit(CSS_REMOVED, &css->flags); |
| 3580 | } |
| 3581 | } |
| 3582 | local_irq_restore(flags); |
| 3583 | return !failed; |
| 3584 | } |
| 3585 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3586 | static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) |
| 3587 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3588 | struct cgroup *cgrp = dentry->d_fsdata; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3589 | struct dentry *d; |
| 3590 | struct cgroup *parent; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3591 | DEFINE_WAIT(wait); |
Kirill A. Shutemov | 4ab7868 | 2010-03-10 15:22:34 -0800 | [diff] [blame] | 3592 | struct cgroup_event *event, *tmp; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3593 | int ret; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3594 | |
| 3595 | /* the vfs holds both inode->i_mutex already */ |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3596 | again: |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3597 | mutex_lock(&cgroup_mutex); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3598 | if (atomic_read(&cgrp->count) != 0) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3599 | mutex_unlock(&cgroup_mutex); |
| 3600 | return -EBUSY; |
| 3601 | } |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3602 | if (!list_empty(&cgrp->children)) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3603 | mutex_unlock(&cgroup_mutex); |
| 3604 | return -EBUSY; |
| 3605 | } |
KAMEZAWA Hiroyuki | 3fa59df | 2008-11-19 15:36:34 -0800 | [diff] [blame] | 3606 | mutex_unlock(&cgroup_mutex); |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3607 | |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 3608 | /* |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 3609 | * In general, subsystem has no css->refcnt after pre_destroy(). But |
| 3610 | * in racy cases, subsystem may have to get css->refcnt after |
| 3611 | * pre_destroy() and it makes rmdir return with -EBUSY. This sometimes |
| 3612 | * make rmdir return -EBUSY too often. To avoid that, we use waitqueue |
| 3613 | * for cgroup's rmdir. CGRP_WAIT_ON_RMDIR is for synchronizing rmdir |
| 3614 | * and subsystem's reference count handling. Please see css_get/put |
| 3615 | * and css_tryget() and cgroup_wakeup_rmdir_waiter() implementation. |
| 3616 | */ |
| 3617 | set_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); |
| 3618 | |
| 3619 | /* |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3620 | * Call pre_destroy handlers of subsys. Notify subsystems |
| 3621 | * that rmdir() request comes. |
KAMEZAWA Hiroyuki | 4fca88c | 2008-02-07 00:14:27 -0800 | [diff] [blame] | 3622 | */ |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3623 | ret = cgroup_call_pre_destroy(cgrp); |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 3624 | if (ret) { |
| 3625 | clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3626 | return ret; |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 3627 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3628 | |
KAMEZAWA Hiroyuki | 3fa59df | 2008-11-19 15:36:34 -0800 | [diff] [blame] | 3629 | mutex_lock(&cgroup_mutex); |
| 3630 | parent = cgrp->parent; |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3631 | if (atomic_read(&cgrp->count) || !list_empty(&cgrp->children)) { |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 3632 | clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3633 | mutex_unlock(&cgroup_mutex); |
| 3634 | return -EBUSY; |
| 3635 | } |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3636 | prepare_to_wait(&cgroup_rmdir_waitq, &wait, TASK_INTERRUPTIBLE); |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3637 | if (!cgroup_clear_css_refs(cgrp)) { |
| 3638 | mutex_unlock(&cgroup_mutex); |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 3639 | /* |
| 3640 | * Because someone may call cgroup_wakeup_rmdir_waiter() before |
| 3641 | * prepare_to_wait(), we need to check this flag. |
| 3642 | */ |
| 3643 | if (test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags)) |
| 3644 | schedule(); |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 3645 | finish_wait(&cgroup_rmdir_waitq, &wait); |
| 3646 | clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); |
| 3647 | if (signal_pending(current)) |
| 3648 | return -EINTR; |
| 3649 | goto again; |
| 3650 | } |
| 3651 | /* NO css_tryget() can success after here. */ |
| 3652 | finish_wait(&cgroup_rmdir_waitq, &wait); |
| 3653 | clear_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3654 | |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3655 | spin_lock(&release_list_lock); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3656 | set_bit(CGRP_REMOVED, &cgrp->flags); |
| 3657 | if (!list_empty(&cgrp->release_list)) |
| 3658 | list_del(&cgrp->release_list); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3659 | spin_unlock(&release_list_lock); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3660 | |
| 3661 | cgroup_lock_hierarchy(cgrp->root); |
| 3662 | /* delete this cgroup from parent->children */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3663 | list_del(&cgrp->sibling); |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3664 | cgroup_unlock_hierarchy(cgrp->root); |
| 3665 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3666 | d = dget(cgrp->dentry); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3667 | |
| 3668 | cgroup_d_remove_dir(d); |
| 3669 | dput(d); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3670 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3671 | set_bit(CGRP_RELEASABLE, &parent->flags); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 3672 | check_for_release(parent); |
| 3673 | |
Kirill A. Shutemov | 4ab7868 | 2010-03-10 15:22:34 -0800 | [diff] [blame] | 3674 | /* |
| 3675 | * Unregister events and notify userspace. |
| 3676 | * Notify userspace about cgroup removing only after rmdir of cgroup |
| 3677 | * directory to avoid race between userspace and kernelspace |
| 3678 | */ |
| 3679 | spin_lock(&cgrp->event_list_lock); |
| 3680 | list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) { |
| 3681 | list_del(&event->list); |
| 3682 | remove_wait_queue(event->wqh, &event->wait); |
| 3683 | eventfd_signal(event->eventfd, 1); |
| 3684 | schedule_work(&event->remove); |
| 3685 | } |
| 3686 | spin_unlock(&cgrp->event_list_lock); |
| 3687 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3688 | mutex_unlock(&cgroup_mutex); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3689 | return 0; |
| 3690 | } |
| 3691 | |
Li Zefan | 06a1192 | 2008-04-29 01:00:07 -0700 | [diff] [blame] | 3692 | static void __init cgroup_init_subsys(struct cgroup_subsys *ss) |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3693 | { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3694 | struct cgroup_subsys_state *css; |
Diego Calleja | cfe36bd | 2007-11-14 16:58:54 -0800 | [diff] [blame] | 3695 | |
| 3696 | printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3697 | |
| 3698 | /* Create the top cgroup state for this subsystem */ |
Li Zefan | 33a68ac | 2009-01-07 18:07:42 -0800 | [diff] [blame] | 3699 | list_add(&ss->sibling, &rootnode.subsys_list); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3700 | ss->root = &rootnode; |
| 3701 | css = ss->create(ss, dummytop); |
| 3702 | /* We don't handle early failures gracefully */ |
| 3703 | BUG_ON(IS_ERR(css)); |
| 3704 | init_cgroup_css(css, ss, dummytop); |
| 3705 | |
Li Zefan | e8d55fd | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 3706 | /* Update the init_css_set to contain a subsys |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 3707 | * pointer to this state - since the subsystem is |
Li Zefan | e8d55fd | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 3708 | * newly registered, all tasks and hence the |
| 3709 | * init_css_set is in the subsystem's top cgroup. */ |
| 3710 | init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3711 | |
| 3712 | need_forkexit_callback |= ss->fork || ss->exit; |
| 3713 | |
Li Zefan | e8d55fd | 2008-04-29 01:00:13 -0700 | [diff] [blame] | 3714 | /* At system boot, before all subsystems have been |
| 3715 | * registered, no tasks have been forked, so we don't |
| 3716 | * need to invoke fork callbacks here. */ |
| 3717 | BUG_ON(!list_empty(&init_task.tasks)); |
| 3718 | |
Paul Menage | 999cd8a | 2009-01-07 18:08:36 -0800 | [diff] [blame] | 3719 | mutex_init(&ss->hierarchy_mutex); |
Li Zefan | cfebe56 | 2009-02-11 13:04:36 -0800 | [diff] [blame] | 3720 | lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3721 | ss->active = 1; |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3722 | |
| 3723 | /* this function shouldn't be used with modular subsystems, since they |
| 3724 | * need to register a subsys_id, among other things */ |
| 3725 | BUG_ON(ss->module); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3726 | } |
| 3727 | |
| 3728 | /** |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3729 | * cgroup_load_subsys: load and register a modular subsystem at runtime |
| 3730 | * @ss: the subsystem to load |
| 3731 | * |
| 3732 | * This function should be called in a modular subsystem's initcall. If the |
Thomas Weber | 8839316 | 2010-03-16 11:47:56 +0100 | [diff] [blame] | 3733 | * subsystem is built as a module, it will be assigned a new subsys_id and set |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3734 | * up for use. If the subsystem is built-in anyway, work is delegated to the |
| 3735 | * simpler cgroup_init_subsys. |
| 3736 | */ |
| 3737 | int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) |
| 3738 | { |
| 3739 | int i; |
| 3740 | struct cgroup_subsys_state *css; |
| 3741 | |
| 3742 | /* check name and function validity */ |
| 3743 | if (ss->name == NULL || strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN || |
| 3744 | ss->create == NULL || ss->destroy == NULL) |
| 3745 | return -EINVAL; |
| 3746 | |
| 3747 | /* |
| 3748 | * we don't support callbacks in modular subsystems. this check is |
| 3749 | * before the ss->module check for consistency; a subsystem that could |
| 3750 | * be a module should still have no callbacks even if the user isn't |
| 3751 | * compiling it as one. |
| 3752 | */ |
| 3753 | if (ss->fork || ss->exit) |
| 3754 | return -EINVAL; |
| 3755 | |
| 3756 | /* |
| 3757 | * an optionally modular subsystem is built-in: we want to do nothing, |
| 3758 | * since cgroup_init_subsys will have already taken care of it. |
| 3759 | */ |
| 3760 | if (ss->module == NULL) { |
| 3761 | /* a few sanity checks */ |
| 3762 | BUG_ON(ss->subsys_id >= CGROUP_BUILTIN_SUBSYS_COUNT); |
| 3763 | BUG_ON(subsys[ss->subsys_id] != ss); |
| 3764 | return 0; |
| 3765 | } |
| 3766 | |
| 3767 | /* |
| 3768 | * need to register a subsys id before anything else - for example, |
| 3769 | * init_cgroup_css needs it. |
| 3770 | */ |
| 3771 | mutex_lock(&cgroup_mutex); |
| 3772 | /* find the first empty slot in the array */ |
| 3773 | for (i = CGROUP_BUILTIN_SUBSYS_COUNT; i < CGROUP_SUBSYS_COUNT; i++) { |
| 3774 | if (subsys[i] == NULL) |
| 3775 | break; |
| 3776 | } |
| 3777 | if (i == CGROUP_SUBSYS_COUNT) { |
| 3778 | /* maximum number of subsystems already registered! */ |
| 3779 | mutex_unlock(&cgroup_mutex); |
| 3780 | return -EBUSY; |
| 3781 | } |
| 3782 | /* assign ourselves the subsys_id */ |
| 3783 | ss->subsys_id = i; |
| 3784 | subsys[i] = ss; |
| 3785 | |
| 3786 | /* |
| 3787 | * no ss->create seems to need anything important in the ss struct, so |
| 3788 | * this can happen first (i.e. before the rootnode attachment). |
| 3789 | */ |
| 3790 | css = ss->create(ss, dummytop); |
| 3791 | if (IS_ERR(css)) { |
| 3792 | /* failure case - need to deassign the subsys[] slot. */ |
| 3793 | subsys[i] = NULL; |
| 3794 | mutex_unlock(&cgroup_mutex); |
| 3795 | return PTR_ERR(css); |
| 3796 | } |
| 3797 | |
| 3798 | list_add(&ss->sibling, &rootnode.subsys_list); |
| 3799 | ss->root = &rootnode; |
| 3800 | |
| 3801 | /* our new subsystem will be attached to the dummy hierarchy. */ |
| 3802 | init_cgroup_css(css, ss, dummytop); |
| 3803 | /* init_idr must be after init_cgroup_css because it sets css->id. */ |
| 3804 | if (ss->use_id) { |
| 3805 | int ret = cgroup_init_idr(ss, css); |
| 3806 | if (ret) { |
| 3807 | dummytop->subsys[ss->subsys_id] = NULL; |
| 3808 | ss->destroy(ss, dummytop); |
| 3809 | subsys[i] = NULL; |
| 3810 | mutex_unlock(&cgroup_mutex); |
| 3811 | return ret; |
| 3812 | } |
| 3813 | } |
| 3814 | |
| 3815 | /* |
| 3816 | * Now we need to entangle the css into the existing css_sets. unlike |
| 3817 | * in cgroup_init_subsys, there are now multiple css_sets, so each one |
| 3818 | * will need a new pointer to it; done by iterating the css_set_table. |
| 3819 | * furthermore, modifying the existing css_sets will corrupt the hash |
| 3820 | * table state, so each changed css_set will need its hash recomputed. |
| 3821 | * this is all done under the css_set_lock. |
| 3822 | */ |
| 3823 | write_lock(&css_set_lock); |
| 3824 | for (i = 0; i < CSS_SET_TABLE_SIZE; i++) { |
| 3825 | struct css_set *cg; |
| 3826 | struct hlist_node *node, *tmp; |
| 3827 | struct hlist_head *bucket = &css_set_table[i], *new_bucket; |
| 3828 | |
| 3829 | hlist_for_each_entry_safe(cg, node, tmp, bucket, hlist) { |
| 3830 | /* skip entries that we already rehashed */ |
| 3831 | if (cg->subsys[ss->subsys_id]) |
| 3832 | continue; |
| 3833 | /* remove existing entry */ |
| 3834 | hlist_del(&cg->hlist); |
| 3835 | /* set new value */ |
| 3836 | cg->subsys[ss->subsys_id] = css; |
| 3837 | /* recompute hash and restore entry */ |
| 3838 | new_bucket = css_set_hash(cg->subsys); |
| 3839 | hlist_add_head(&cg->hlist, new_bucket); |
| 3840 | } |
| 3841 | } |
| 3842 | write_unlock(&css_set_lock); |
| 3843 | |
| 3844 | mutex_init(&ss->hierarchy_mutex); |
| 3845 | lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key); |
| 3846 | ss->active = 1; |
| 3847 | |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3848 | /* success! */ |
| 3849 | mutex_unlock(&cgroup_mutex); |
| 3850 | return 0; |
| 3851 | } |
| 3852 | EXPORT_SYMBOL_GPL(cgroup_load_subsys); |
| 3853 | |
| 3854 | /** |
Ben Blum | cf5d594 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3855 | * cgroup_unload_subsys: unload a modular subsystem |
| 3856 | * @ss: the subsystem to unload |
| 3857 | * |
| 3858 | * This function should be called in a modular subsystem's exitcall. When this |
| 3859 | * function is invoked, the refcount on the subsystem's module will be 0, so |
| 3860 | * the subsystem will not be attached to any hierarchy. |
| 3861 | */ |
| 3862 | void cgroup_unload_subsys(struct cgroup_subsys *ss) |
| 3863 | { |
| 3864 | struct cg_cgroup_link *link; |
| 3865 | struct hlist_head *hhead; |
| 3866 | |
| 3867 | BUG_ON(ss->module == NULL); |
| 3868 | |
| 3869 | /* |
| 3870 | * we shouldn't be called if the subsystem is in use, and the use of |
| 3871 | * try_module_get in parse_cgroupfs_options should ensure that it |
| 3872 | * doesn't start being used while we're killing it off. |
| 3873 | */ |
| 3874 | BUG_ON(ss->root != &rootnode); |
| 3875 | |
| 3876 | mutex_lock(&cgroup_mutex); |
| 3877 | /* deassign the subsys_id */ |
| 3878 | BUG_ON(ss->subsys_id < CGROUP_BUILTIN_SUBSYS_COUNT); |
| 3879 | subsys[ss->subsys_id] = NULL; |
| 3880 | |
| 3881 | /* remove subsystem from rootnode's list of subsystems */ |
| 3882 | list_del(&ss->sibling); |
| 3883 | |
| 3884 | /* |
| 3885 | * disentangle the css from all css_sets attached to the dummytop. as |
| 3886 | * in loading, we need to pay our respects to the hashtable gods. |
| 3887 | */ |
| 3888 | write_lock(&css_set_lock); |
| 3889 | list_for_each_entry(link, &dummytop->css_sets, cgrp_link_list) { |
| 3890 | struct css_set *cg = link->cg; |
| 3891 | |
| 3892 | hlist_del(&cg->hlist); |
| 3893 | BUG_ON(!cg->subsys[ss->subsys_id]); |
| 3894 | cg->subsys[ss->subsys_id] = NULL; |
| 3895 | hhead = css_set_hash(cg->subsys); |
| 3896 | hlist_add_head(&cg->hlist, hhead); |
| 3897 | } |
| 3898 | write_unlock(&css_set_lock); |
| 3899 | |
| 3900 | /* |
| 3901 | * remove subsystem's css from the dummytop and free it - need to free |
| 3902 | * before marking as null because ss->destroy needs the cgrp->subsys |
| 3903 | * pointer to find their state. note that this also takes care of |
| 3904 | * freeing the css_id. |
| 3905 | */ |
| 3906 | ss->destroy(ss, dummytop); |
| 3907 | dummytop->subsys[ss->subsys_id] = NULL; |
| 3908 | |
| 3909 | mutex_unlock(&cgroup_mutex); |
| 3910 | } |
| 3911 | EXPORT_SYMBOL_GPL(cgroup_unload_subsys); |
| 3912 | |
| 3913 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3914 | * cgroup_init_early - cgroup initialization at system boot |
| 3915 | * |
| 3916 | * Initialize cgroups at system boot, and initialize any |
| 3917 | * subsystems that request early init. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3918 | */ |
| 3919 | int __init cgroup_init_early(void) |
| 3920 | { |
| 3921 | int i; |
Lai Jiangshan | 146aa1b | 2008-10-18 20:28:03 -0700 | [diff] [blame] | 3922 | atomic_set(&init_css_set.refcount, 1); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 3923 | INIT_LIST_HEAD(&init_css_set.cg_links); |
| 3924 | INIT_LIST_HEAD(&init_css_set.tasks); |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 3925 | INIT_HLIST_NODE(&init_css_set.hlist); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 3926 | css_set_count = 1; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3927 | init_cgroup_root(&rootnode); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 3928 | root_count = 1; |
| 3929 | init_task.cgroups = &init_css_set; |
| 3930 | |
| 3931 | init_css_set_link.cg = &init_css_set; |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 3932 | init_css_set_link.cgrp = dummytop; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 3933 | list_add(&init_css_set_link.cgrp_link_list, |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 3934 | &rootnode.top_cgroup.css_sets); |
| 3935 | list_add(&init_css_set_link.cg_link_list, |
| 3936 | &init_css_set.cg_links); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3937 | |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 3938 | for (i = 0; i < CSS_SET_TABLE_SIZE; i++) |
| 3939 | INIT_HLIST_HEAD(&css_set_table[i]); |
| 3940 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3941 | /* at bootup time, we don't worry about modular subsystems */ |
| 3942 | for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3943 | struct cgroup_subsys *ss = subsys[i]; |
| 3944 | |
| 3945 | BUG_ON(!ss->name); |
| 3946 | BUG_ON(strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN); |
| 3947 | BUG_ON(!ss->create); |
| 3948 | BUG_ON(!ss->destroy); |
| 3949 | if (ss->subsys_id != i) { |
Diego Calleja | cfe36bd | 2007-11-14 16:58:54 -0800 | [diff] [blame] | 3950 | printk(KERN_ERR "cgroup: Subsys %s id == %d\n", |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3951 | ss->name, ss->subsys_id); |
| 3952 | BUG(); |
| 3953 | } |
| 3954 | |
| 3955 | if (ss->early_init) |
| 3956 | cgroup_init_subsys(ss); |
| 3957 | } |
| 3958 | return 0; |
| 3959 | } |
| 3960 | |
| 3961 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 3962 | * cgroup_init - cgroup initialization |
| 3963 | * |
| 3964 | * Register cgroup filesystem and /proc file, and initialize |
| 3965 | * any subsystems that didn't request early init. |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3966 | */ |
| 3967 | int __init cgroup_init(void) |
| 3968 | { |
| 3969 | int err; |
| 3970 | int i; |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 3971 | struct hlist_head *hhead; |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 3972 | |
| 3973 | err = bdi_init(&cgroup_backing_dev_info); |
| 3974 | if (err) |
| 3975 | return err; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3976 | |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 3977 | /* at bootup time, we don't worry about modular subsystems */ |
| 3978 | for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3979 | struct cgroup_subsys *ss = subsys[i]; |
| 3980 | if (!ss->early_init) |
| 3981 | cgroup_init_subsys(ss); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 3982 | if (ss->use_id) |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 3983 | cgroup_init_idr(ss, init_css_set.subsys[ss->subsys_id]); |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3984 | } |
| 3985 | |
Li Zefan | 472b105 | 2008-04-29 01:00:11 -0700 | [diff] [blame] | 3986 | /* Add init_css_set to the hash table */ |
| 3987 | hhead = css_set_hash(init_css_set.subsys); |
| 3988 | hlist_add_head(&init_css_set.hlist, hhead); |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 3989 | BUG_ON(!init_root_id(&rootnode)); |
Greg KH | 676db4a | 2010-08-05 13:53:35 -0700 | [diff] [blame] | 3990 | |
| 3991 | cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj); |
| 3992 | if (!cgroup_kobj) { |
| 3993 | err = -ENOMEM; |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 3994 | goto out; |
Greg KH | 676db4a | 2010-08-05 13:53:35 -0700 | [diff] [blame] | 3995 | } |
| 3996 | |
| 3997 | err = register_filesystem(&cgroup_fs_type); |
| 3998 | if (err < 0) { |
| 3999 | kobject_put(cgroup_kobj); |
| 4000 | goto out; |
| 4001 | } |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 4002 | |
Li Zefan | 46ae220 | 2008-04-29 01:00:08 -0700 | [diff] [blame] | 4003 | proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4004 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 4005 | out: |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4006 | if (err) |
| 4007 | bdi_destroy(&cgroup_backing_dev_info); |
| 4008 | |
Paul Menage | ddbcc7e | 2007-10-18 23:39:30 -0700 | [diff] [blame] | 4009 | return err; |
| 4010 | } |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4011 | |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4012 | /* |
| 4013 | * proc_cgroup_show() |
| 4014 | * - Print task's cgroup paths into seq_file, one line for each hierarchy |
| 4015 | * - Used for /proc/<pid>/cgroup. |
| 4016 | * - No need to task_lock(tsk) on this tsk->cgroup reference, as it |
| 4017 | * doesn't really matter if tsk->cgroup changes after we read it, |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 4018 | * and we take cgroup_mutex, keeping cgroup_attach_task() from changing it |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4019 | * anyway. No need to check that tsk->cgroup != NULL, thanks to |
| 4020 | * the_top_cgroup_hack in cgroup_exit(), which sets an exiting tasks |
| 4021 | * cgroup to top_cgroup. |
| 4022 | */ |
| 4023 | |
| 4024 | /* TODO: Use a proper seq_file iterator */ |
| 4025 | static int proc_cgroup_show(struct seq_file *m, void *v) |
| 4026 | { |
| 4027 | struct pid *pid; |
| 4028 | struct task_struct *tsk; |
| 4029 | char *buf; |
| 4030 | int retval; |
| 4031 | struct cgroupfs_root *root; |
| 4032 | |
| 4033 | retval = -ENOMEM; |
| 4034 | buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| 4035 | if (!buf) |
| 4036 | goto out; |
| 4037 | |
| 4038 | retval = -ESRCH; |
| 4039 | pid = m->private; |
| 4040 | tsk = get_pid_task(pid, PIDTYPE_PID); |
| 4041 | if (!tsk) |
| 4042 | goto out_free; |
| 4043 | |
| 4044 | retval = 0; |
| 4045 | |
| 4046 | mutex_lock(&cgroup_mutex); |
| 4047 | |
Li Zefan | e5f6a86 | 2009-01-07 18:07:41 -0800 | [diff] [blame] | 4048 | for_each_active_root(root) { |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4049 | struct cgroup_subsys *ss; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4050 | struct cgroup *cgrp; |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4051 | int count = 0; |
| 4052 | |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 4053 | seq_printf(m, "%d:", root->hierarchy_id); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4054 | for_each_subsys(root, ss) |
| 4055 | seq_printf(m, "%s%s", count++ ? "," : "", ss->name); |
Paul Menage | c6d57f3 | 2009-09-23 15:56:19 -0700 | [diff] [blame] | 4056 | if (strlen(root->name)) |
| 4057 | seq_printf(m, "%sname=%s", count ? "," : "", |
| 4058 | root->name); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4059 | seq_putc(m, ':'); |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 4060 | cgrp = task_cgroup_from_root(tsk, root); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4061 | retval = cgroup_path(cgrp, buf, PAGE_SIZE); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4062 | if (retval < 0) |
| 4063 | goto out_unlock; |
| 4064 | seq_puts(m, buf); |
| 4065 | seq_putc(m, '\n'); |
| 4066 | } |
| 4067 | |
| 4068 | out_unlock: |
| 4069 | mutex_unlock(&cgroup_mutex); |
| 4070 | put_task_struct(tsk); |
| 4071 | out_free: |
| 4072 | kfree(buf); |
| 4073 | out: |
| 4074 | return retval; |
| 4075 | } |
| 4076 | |
| 4077 | static int cgroup_open(struct inode *inode, struct file *file) |
| 4078 | { |
| 4079 | struct pid *pid = PROC_I(inode)->pid; |
| 4080 | return single_open(file, proc_cgroup_show, pid); |
| 4081 | } |
| 4082 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 4083 | const struct file_operations proc_cgroup_operations = { |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4084 | .open = cgroup_open, |
| 4085 | .read = seq_read, |
| 4086 | .llseek = seq_lseek, |
| 4087 | .release = single_release, |
| 4088 | }; |
| 4089 | |
| 4090 | /* Display information about each subsystem and each hierarchy */ |
| 4091 | static int proc_cgroupstats_show(struct seq_file *m, void *v) |
| 4092 | { |
| 4093 | int i; |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4094 | |
Paul Menage | 8bab8dd | 2008-04-04 14:29:57 -0700 | [diff] [blame] | 4095 | seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n"); |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 4096 | /* |
| 4097 | * ideally we don't want subsystems moving around while we do this. |
| 4098 | * cgroup_mutex is also necessary to guarantee an atomic snapshot of |
| 4099 | * subsys/hierarchy state. |
| 4100 | */ |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4101 | mutex_lock(&cgroup_mutex); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4102 | for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { |
| 4103 | struct cgroup_subsys *ss = subsys[i]; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 4104 | if (ss == NULL) |
| 4105 | continue; |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 4106 | seq_printf(m, "%s\t%d\t%d\t%d\n", |
| 4107 | ss->name, ss->root->hierarchy_id, |
Paul Menage | 8bab8dd | 2008-04-04 14:29:57 -0700 | [diff] [blame] | 4108 | ss->root->number_of_cgroups, !ss->disabled); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4109 | } |
| 4110 | mutex_unlock(&cgroup_mutex); |
| 4111 | return 0; |
| 4112 | } |
| 4113 | |
| 4114 | static int cgroupstats_open(struct inode *inode, struct file *file) |
| 4115 | { |
Al Viro | 9dce07f | 2008-03-29 03:07:28 +0000 | [diff] [blame] | 4116 | return single_open(file, proc_cgroupstats_show, NULL); |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4117 | } |
| 4118 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 4119 | static const struct file_operations proc_cgroupstats_operations = { |
Paul Menage | a424316 | 2007-10-18 23:39:35 -0700 | [diff] [blame] | 4120 | .open = cgroupstats_open, |
| 4121 | .read = seq_read, |
| 4122 | .llseek = seq_lseek, |
| 4123 | .release = single_release, |
| 4124 | }; |
| 4125 | |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4126 | /** |
| 4127 | * cgroup_fork - attach newly forked task to its parents cgroup. |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4128 | * @child: pointer to task_struct of forking parent process. |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4129 | * |
| 4130 | * Description: A task inherits its parent's cgroup at fork(). |
| 4131 | * |
| 4132 | * A pointer to the shared css_set was automatically copied in |
| 4133 | * fork.c by dup_task_struct(). However, we ignore that copy, since |
| 4134 | * it was not made under the protection of RCU or cgroup_mutex, so |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 4135 | * might no longer be a valid cgroup pointer. cgroup_attach_task() might |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4136 | * have already changed current->cgroups, allowing the previously |
| 4137 | * referenced cgroup group to be removed and freed. |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4138 | * |
| 4139 | * At the point that cgroup_fork() is called, 'current' is the parent |
| 4140 | * task, and the passed argument 'child' points to the child task. |
| 4141 | */ |
| 4142 | void cgroup_fork(struct task_struct *child) |
| 4143 | { |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4144 | task_lock(current); |
| 4145 | child->cgroups = current->cgroups; |
| 4146 | get_css_set(child->cgroups); |
| 4147 | task_unlock(current); |
| 4148 | INIT_LIST_HEAD(&child->cg_list); |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4149 | } |
| 4150 | |
| 4151 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4152 | * cgroup_fork_callbacks - run fork callbacks |
| 4153 | * @child: the new task |
| 4154 | * |
| 4155 | * Called on a new task very soon before adding it to the |
| 4156 | * tasklist. No need to take any locks since no-one can |
| 4157 | * be operating on this task. |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4158 | */ |
| 4159 | void cgroup_fork_callbacks(struct task_struct *child) |
| 4160 | { |
| 4161 | if (need_forkexit_callback) { |
| 4162 | int i; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 4163 | /* |
| 4164 | * forkexit callbacks are only supported for builtin |
| 4165 | * subsystems, and the builtin section of the subsys array is |
| 4166 | * immutable, so we don't need to lock the subsys array here. |
| 4167 | */ |
| 4168 | for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4169 | struct cgroup_subsys *ss = subsys[i]; |
| 4170 | if (ss->fork) |
| 4171 | ss->fork(ss, child); |
| 4172 | } |
| 4173 | } |
| 4174 | } |
| 4175 | |
| 4176 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4177 | * cgroup_post_fork - called on a new task after adding it to the task list |
| 4178 | * @child: the task in question |
| 4179 | * |
| 4180 | * Adds the task to the list running through its css_set if necessary. |
| 4181 | * Has to be after the task is visible on the task list in case we race |
| 4182 | * with the first call to cgroup_iter_start() - to guarantee that the |
| 4183 | * new task ends up on its list. |
| 4184 | */ |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4185 | void cgroup_post_fork(struct task_struct *child) |
| 4186 | { |
| 4187 | if (use_task_css_set_links) { |
| 4188 | write_lock(&css_set_lock); |
Lai Jiangshan | b12b533 | 2009-01-07 18:07:36 -0800 | [diff] [blame] | 4189 | task_lock(child); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4190 | if (list_empty(&child->cg_list)) |
| 4191 | list_add(&child->cg_list, &child->cgroups->tasks); |
Lai Jiangshan | b12b533 | 2009-01-07 18:07:36 -0800 | [diff] [blame] | 4192 | task_unlock(child); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4193 | write_unlock(&css_set_lock); |
| 4194 | } |
| 4195 | } |
| 4196 | /** |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4197 | * cgroup_exit - detach cgroup from exiting task |
| 4198 | * @tsk: pointer to task_struct of exiting process |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4199 | * @run_callback: run exit callbacks? |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4200 | * |
| 4201 | * Description: Detach cgroup from @tsk and release it. |
| 4202 | * |
| 4203 | * Note that cgroups marked notify_on_release force every task in |
| 4204 | * them to take the global cgroup_mutex mutex when exiting. |
| 4205 | * This could impact scaling on very large systems. Be reluctant to |
| 4206 | * use notify_on_release cgroups where very high task exit scaling |
| 4207 | * is required on large systems. |
| 4208 | * |
| 4209 | * the_top_cgroup_hack: |
| 4210 | * |
| 4211 | * Set the exiting tasks cgroup to the root cgroup (top_cgroup). |
| 4212 | * |
| 4213 | * We call cgroup_exit() while the task is still competent to |
| 4214 | * handle notify_on_release(), then leave the task attached to the |
| 4215 | * root cgroup in each hierarchy for the remainder of its exit. |
| 4216 | * |
| 4217 | * To do this properly, we would increment the reference count on |
| 4218 | * top_cgroup, and near the very end of the kernel/exit.c do_exit() |
| 4219 | * code we would add a second cgroup function call, to drop that |
| 4220 | * reference. This would just create an unnecessary hot spot on |
| 4221 | * the top_cgroup reference count, to no avail. |
| 4222 | * |
| 4223 | * Normally, holding a reference to a cgroup without bumping its |
| 4224 | * count is unsafe. The cgroup could go away, or someone could |
| 4225 | * attach us to a different cgroup, decrementing the count on |
| 4226 | * the first cgroup that we never incremented. But in this case, |
| 4227 | * top_cgroup isn't going away, and either task has PF_EXITING set, |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 4228 | * which wards off any cgroup_attach_task() attempts, or task is a failed |
| 4229 | * fork, never visible to cgroup_attach_task. |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4230 | */ |
| 4231 | void cgroup_exit(struct task_struct *tsk, int run_callbacks) |
| 4232 | { |
| 4233 | int i; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4234 | struct css_set *cg; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4235 | |
| 4236 | if (run_callbacks && need_forkexit_callback) { |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 4237 | /* |
| 4238 | * modular subsystems can't use callbacks, so no need to lock |
| 4239 | * the subsys array |
| 4240 | */ |
| 4241 | for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4242 | struct cgroup_subsys *ss = subsys[i]; |
| 4243 | if (ss->exit) |
| 4244 | ss->exit(ss, tsk); |
| 4245 | } |
| 4246 | } |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4247 | |
| 4248 | /* |
| 4249 | * Unlink from the css_set task list if necessary. |
| 4250 | * Optimistically check cg_list before taking |
| 4251 | * css_set_lock |
| 4252 | */ |
| 4253 | if (!list_empty(&tsk->cg_list)) { |
| 4254 | write_lock(&css_set_lock); |
| 4255 | if (!list_empty(&tsk->cg_list)) |
| 4256 | list_del(&tsk->cg_list); |
| 4257 | write_unlock(&css_set_lock); |
| 4258 | } |
| 4259 | |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4260 | /* Reassign the task to the init_css_set. */ |
| 4261 | task_lock(tsk); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4262 | cg = tsk->cgroups; |
| 4263 | tsk->cgroups = &init_css_set; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4264 | task_unlock(tsk); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4265 | if (cg) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4266 | put_css_set_taskexit(cg); |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 4267 | } |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4268 | |
| 4269 | /** |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4270 | * cgroup_clone - clone the cgroup the given subsystem is attached to |
| 4271 | * @tsk: the task to be moved |
| 4272 | * @subsys: the given subsystem |
Serge E. Hallyn | e885dcd | 2008-07-25 01:47:06 -0700 | [diff] [blame] | 4273 | * @nodename: the name for the new cgroup |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4274 | * |
| 4275 | * Duplicate the current cgroup in the hierarchy that the given |
| 4276 | * subsystem is attached to, and move this task into the new |
| 4277 | * child. |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4278 | */ |
Serge E. Hallyn | e885dcd | 2008-07-25 01:47:06 -0700 | [diff] [blame] | 4279 | int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys, |
| 4280 | char *nodename) |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4281 | { |
| 4282 | struct dentry *dentry; |
| 4283 | int ret = 0; |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4284 | struct cgroup *parent, *child; |
| 4285 | struct inode *inode; |
| 4286 | struct css_set *cg; |
| 4287 | struct cgroupfs_root *root; |
| 4288 | struct cgroup_subsys *ss; |
| 4289 | |
| 4290 | /* We shouldn't be called by an unregistered subsystem */ |
| 4291 | BUG_ON(!subsys->active); |
| 4292 | |
| 4293 | /* First figure out what hierarchy and cgroup we're dealing |
| 4294 | * with, and pin them so we can drop cgroup_mutex */ |
| 4295 | mutex_lock(&cgroup_mutex); |
| 4296 | again: |
| 4297 | root = subsys->root; |
| 4298 | if (root == &rootnode) { |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4299 | mutex_unlock(&cgroup_mutex); |
| 4300 | return 0; |
| 4301 | } |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4302 | |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4303 | /* Pin the hierarchy */ |
Li Zefan | 1404f06 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 4304 | if (!atomic_inc_not_zero(&root->sb->s_active)) { |
Li Zefan | 7b574b7 | 2009-01-04 12:00:45 -0800 | [diff] [blame] | 4305 | /* We race with the final deactivate_super() */ |
| 4306 | mutex_unlock(&cgroup_mutex); |
| 4307 | return 0; |
| 4308 | } |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4309 | |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4310 | /* Keep the cgroup alive */ |
Li Zefan | 1404f06 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 4311 | task_lock(tsk); |
| 4312 | parent = task_cgroup(tsk, subsys->subsys_id); |
| 4313 | cg = tsk->cgroups; |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4314 | get_css_set(cg); |
Lai Jiangshan | 104cbd5 | 2009-01-07 18:07:38 -0800 | [diff] [blame] | 4315 | task_unlock(tsk); |
Li Zefan | 1404f06 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 4316 | |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4317 | mutex_unlock(&cgroup_mutex); |
| 4318 | |
| 4319 | /* Now do the VFS work to create a cgroup */ |
| 4320 | inode = parent->dentry->d_inode; |
| 4321 | |
| 4322 | /* Hold the parent directory mutex across this operation to |
| 4323 | * stop anyone else deleting the new cgroup */ |
| 4324 | mutex_lock(&inode->i_mutex); |
| 4325 | dentry = lookup_one_len(nodename, parent->dentry, strlen(nodename)); |
| 4326 | if (IS_ERR(dentry)) { |
| 4327 | printk(KERN_INFO |
Diego Calleja | cfe36bd | 2007-11-14 16:58:54 -0800 | [diff] [blame] | 4328 | "cgroup: Couldn't allocate dentry for %s: %ld\n", nodename, |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4329 | PTR_ERR(dentry)); |
| 4330 | ret = PTR_ERR(dentry); |
| 4331 | goto out_release; |
| 4332 | } |
| 4333 | |
| 4334 | /* Create the cgroup directory, which also creates the cgroup */ |
Li Zefan | 75139b8 | 2009-01-07 18:07:33 -0800 | [diff] [blame] | 4335 | ret = vfs_mkdir(inode, dentry, 0755); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4336 | child = __d_cgrp(dentry); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4337 | dput(dentry); |
| 4338 | if (ret) { |
| 4339 | printk(KERN_INFO |
| 4340 | "Failed to create cgroup %s: %d\n", nodename, |
| 4341 | ret); |
| 4342 | goto out_release; |
| 4343 | } |
| 4344 | |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4345 | /* The cgroup now exists. Retake cgroup_mutex and check |
| 4346 | * that we're still in the same state that we thought we |
| 4347 | * were. */ |
| 4348 | mutex_lock(&cgroup_mutex); |
| 4349 | if ((root != subsys->root) || |
| 4350 | (parent != task_cgroup(tsk, subsys->subsys_id))) { |
| 4351 | /* Aargh, we raced ... */ |
| 4352 | mutex_unlock(&inode->i_mutex); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4353 | put_css_set(cg); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4354 | |
Li Zefan | 1404f06 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 4355 | deactivate_super(root->sb); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4356 | /* The cgroup is still accessible in the VFS, but |
| 4357 | * we're not going to try to rmdir() it at this |
| 4358 | * point. */ |
| 4359 | printk(KERN_INFO |
| 4360 | "Race in cgroup_clone() - leaking cgroup %s\n", |
| 4361 | nodename); |
| 4362 | goto again; |
| 4363 | } |
| 4364 | |
| 4365 | /* do any required auto-setup */ |
| 4366 | for_each_subsys(root, ss) { |
| 4367 | if (ss->post_clone) |
| 4368 | ss->post_clone(ss, child); |
| 4369 | } |
| 4370 | |
| 4371 | /* All seems fine. Finish by moving the task into the new cgroup */ |
Cliff Wickman | 956db3c | 2008-02-07 00:14:43 -0800 | [diff] [blame] | 4372 | ret = cgroup_attach_task(child, tsk); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4373 | mutex_unlock(&cgroup_mutex); |
| 4374 | |
| 4375 | out_release: |
| 4376 | mutex_unlock(&inode->i_mutex); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4377 | |
| 4378 | mutex_lock(&cgroup_mutex); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 4379 | put_css_set(cg); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4380 | mutex_unlock(&cgroup_mutex); |
Li Zefan | 1404f06 | 2009-01-29 14:25:21 -0800 | [diff] [blame] | 4381 | deactivate_super(root->sb); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4382 | return ret; |
| 4383 | } |
| 4384 | |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4385 | /** |
Grzegorz Nosek | 313e924 | 2009-04-02 16:57:23 -0700 | [diff] [blame] | 4386 | * cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4387 | * @cgrp: the cgroup in question |
Grzegorz Nosek | 313e924 | 2009-04-02 16:57:23 -0700 | [diff] [blame] | 4388 | * @task: the task in question |
Li Zefan | a043e3b | 2008-02-23 15:24:09 -0800 | [diff] [blame] | 4389 | * |
Grzegorz Nosek | 313e924 | 2009-04-02 16:57:23 -0700 | [diff] [blame] | 4390 | * See if @cgrp is a descendant of @task's cgroup in the appropriate |
| 4391 | * hierarchy. |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4392 | * |
| 4393 | * If we are sending in dummytop, then presumably we are creating |
| 4394 | * the top cgroup in the subsystem. |
| 4395 | * |
| 4396 | * Called only by the ns (nsproxy) cgroup. |
| 4397 | */ |
Grzegorz Nosek | 313e924 | 2009-04-02 16:57:23 -0700 | [diff] [blame] | 4398 | int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task) |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4399 | { |
| 4400 | int ret; |
| 4401 | struct cgroup *target; |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4402 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4403 | if (cgrp == dummytop) |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4404 | return 1; |
| 4405 | |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 4406 | target = task_cgroup_from_root(task, cgrp->root); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4407 | while (cgrp != target && cgrp!= cgrp->top_cgroup) |
| 4408 | cgrp = cgrp->parent; |
| 4409 | ret = (cgrp == target); |
Paul Menage | 697f416 | 2007-10-18 23:39:34 -0700 | [diff] [blame] | 4410 | return ret; |
| 4411 | } |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4412 | |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4413 | static void check_for_release(struct cgroup *cgrp) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4414 | { |
| 4415 | /* All of these checks rely on RCU to keep the cgroup |
| 4416 | * structure alive */ |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4417 | if (cgroup_is_releasable(cgrp) && !atomic_read(&cgrp->count) |
| 4418 | && list_empty(&cgrp->children) && !cgroup_has_css_refs(cgrp)) { |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4419 | /* Control Group is currently removeable. If it's not |
| 4420 | * already queued for a userspace notification, queue |
| 4421 | * it now */ |
| 4422 | int need_schedule_work = 0; |
| 4423 | spin_lock(&release_list_lock); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4424 | if (!cgroup_is_removed(cgrp) && |
| 4425 | list_empty(&cgrp->release_list)) { |
| 4426 | list_add(&cgrp->release_list, &release_list); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4427 | need_schedule_work = 1; |
| 4428 | } |
| 4429 | spin_unlock(&release_list_lock); |
| 4430 | if (need_schedule_work) |
| 4431 | schedule_work(&release_agent_work); |
| 4432 | } |
| 4433 | } |
| 4434 | |
Daisuke Nishimura | d7b9fff | 2010-03-10 15:22:05 -0800 | [diff] [blame] | 4435 | /* Caller must verify that the css is not for root cgroup */ |
| 4436 | void __css_put(struct cgroup_subsys_state *css, int count) |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4437 | { |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4438 | struct cgroup *cgrp = css->cgroup; |
KAMEZAWA Hiroyuki | 3dece83 | 2009-10-01 15:44:09 -0700 | [diff] [blame] | 4439 | int val; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4440 | rcu_read_lock(); |
Daisuke Nishimura | d7b9fff | 2010-03-10 15:22:05 -0800 | [diff] [blame] | 4441 | val = atomic_sub_return(count, &css->refcnt); |
KAMEZAWA Hiroyuki | 3dece83 | 2009-10-01 15:44:09 -0700 | [diff] [blame] | 4442 | if (val == 1) { |
KAMEZAWA Hiroyuki | ec64f51 | 2009-04-02 16:57:26 -0700 | [diff] [blame] | 4443 | if (notify_on_release(cgrp)) { |
| 4444 | set_bit(CGRP_RELEASABLE, &cgrp->flags); |
| 4445 | check_for_release(cgrp); |
| 4446 | } |
KAMEZAWA Hiroyuki | 8870326 | 2009-07-29 15:04:06 -0700 | [diff] [blame] | 4447 | cgroup_wakeup_rmdir_waiter(cgrp); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4448 | } |
| 4449 | rcu_read_unlock(); |
KAMEZAWA Hiroyuki | 3dece83 | 2009-10-01 15:44:09 -0700 | [diff] [blame] | 4450 | WARN_ON_ONCE(val < 1); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4451 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 4452 | EXPORT_SYMBOL_GPL(__css_put); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4453 | |
| 4454 | /* |
| 4455 | * Notify userspace when a cgroup is released, by running the |
| 4456 | * configured release agent with the name of the cgroup (path |
| 4457 | * relative to the root of cgroup file system) as the argument. |
| 4458 | * |
| 4459 | * Most likely, this user command will try to rmdir this cgroup. |
| 4460 | * |
| 4461 | * This races with the possibility that some other task will be |
| 4462 | * attached to this cgroup before it is removed, or that some other |
| 4463 | * user task will 'mkdir' a child cgroup of this cgroup. That's ok. |
| 4464 | * The presumed 'rmdir' will fail quietly if this cgroup is no longer |
| 4465 | * unused, and this cgroup will be reprieved from its death sentence, |
| 4466 | * to continue to serve a useful existence. Next time it's released, |
| 4467 | * we will get notified again, if it still has 'notify_on_release' set. |
| 4468 | * |
| 4469 | * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which |
| 4470 | * means only wait until the task is successfully execve()'d. The |
| 4471 | * separate release agent task is forked by call_usermodehelper(), |
| 4472 | * then control in this thread returns here, without waiting for the |
| 4473 | * release agent task. We don't bother to wait because the caller of |
| 4474 | * this routine has no use for the exit status of the release agent |
| 4475 | * task, so no sense holding our caller up for that. |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4476 | */ |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4477 | static void cgroup_release_agent(struct work_struct *work) |
| 4478 | { |
| 4479 | BUG_ON(work != &release_agent_work); |
| 4480 | mutex_lock(&cgroup_mutex); |
| 4481 | spin_lock(&release_list_lock); |
| 4482 | while (!list_empty(&release_list)) { |
| 4483 | char *argv[3], *envp[3]; |
| 4484 | int i; |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 4485 | char *pathbuf = NULL, *agentbuf = NULL; |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4486 | struct cgroup *cgrp = list_entry(release_list.next, |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4487 | struct cgroup, |
| 4488 | release_list); |
Paul Menage | bd89aab | 2007-10-18 23:40:44 -0700 | [diff] [blame] | 4489 | list_del_init(&cgrp->release_list); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4490 | spin_unlock(&release_list_lock); |
| 4491 | pathbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 4492 | if (!pathbuf) |
| 4493 | goto continue_free; |
| 4494 | if (cgroup_path(cgrp, pathbuf, PAGE_SIZE) < 0) |
| 4495 | goto continue_free; |
| 4496 | agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL); |
| 4497 | if (!agentbuf) |
| 4498 | goto continue_free; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4499 | |
| 4500 | i = 0; |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 4501 | argv[i++] = agentbuf; |
| 4502 | argv[i++] = pathbuf; |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4503 | argv[i] = NULL; |
| 4504 | |
| 4505 | i = 0; |
| 4506 | /* minimal command environment */ |
| 4507 | envp[i++] = "HOME=/"; |
| 4508 | envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; |
| 4509 | envp[i] = NULL; |
| 4510 | |
| 4511 | /* Drop the lock while we invoke the usermode helper, |
| 4512 | * since the exec could involve hitting disk and hence |
| 4513 | * be a slow process */ |
| 4514 | mutex_unlock(&cgroup_mutex); |
| 4515 | call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4516 | mutex_lock(&cgroup_mutex); |
Paul Menage | e788e06 | 2008-07-25 01:46:59 -0700 | [diff] [blame] | 4517 | continue_free: |
| 4518 | kfree(pathbuf); |
| 4519 | kfree(agentbuf); |
Paul Menage | 81a6a5c | 2007-10-18 23:39:38 -0700 | [diff] [blame] | 4520 | spin_lock(&release_list_lock); |
| 4521 | } |
| 4522 | spin_unlock(&release_list_lock); |
| 4523 | mutex_unlock(&cgroup_mutex); |
| 4524 | } |
Paul Menage | 8bab8dd | 2008-04-04 14:29:57 -0700 | [diff] [blame] | 4525 | |
| 4526 | static int __init cgroup_disable(char *str) |
| 4527 | { |
| 4528 | int i; |
| 4529 | char *token; |
| 4530 | |
| 4531 | while ((token = strsep(&str, ",")) != NULL) { |
| 4532 | if (!*token) |
| 4533 | continue; |
Ben Blum | aae8aab | 2010-03-10 15:22:07 -0800 | [diff] [blame] | 4534 | /* |
| 4535 | * cgroup_disable, being at boot time, can't know about module |
| 4536 | * subsystems, so we don't worry about them. |
| 4537 | */ |
| 4538 | for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) { |
Paul Menage | 8bab8dd | 2008-04-04 14:29:57 -0700 | [diff] [blame] | 4539 | struct cgroup_subsys *ss = subsys[i]; |
| 4540 | |
| 4541 | if (!strcmp(token, ss->name)) { |
| 4542 | ss->disabled = 1; |
| 4543 | printk(KERN_INFO "Disabling %s control group" |
| 4544 | " subsystem\n", ss->name); |
| 4545 | break; |
| 4546 | } |
| 4547 | } |
| 4548 | } |
| 4549 | return 1; |
| 4550 | } |
| 4551 | __setup("cgroup_disable=", cgroup_disable); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4552 | |
| 4553 | /* |
| 4554 | * Functons for CSS ID. |
| 4555 | */ |
| 4556 | |
| 4557 | /* |
| 4558 | *To get ID other than 0, this should be called when !cgroup_is_removed(). |
| 4559 | */ |
| 4560 | unsigned short css_id(struct cgroup_subsys_state *css) |
| 4561 | { |
KAMEZAWA Hiroyuki | 7f0f154 | 2010-05-11 14:06:58 -0700 | [diff] [blame] | 4562 | struct css_id *cssid; |
| 4563 | |
| 4564 | /* |
| 4565 | * This css_id() can return correct value when somone has refcnt |
| 4566 | * on this or this is under rcu_read_lock(). Once css->id is allocated, |
| 4567 | * it's unchanged until freed. |
| 4568 | */ |
| 4569 | cssid = rcu_dereference_check(css->id, |
| 4570 | rcu_read_lock_held() || atomic_read(&css->refcnt)); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4571 | |
| 4572 | if (cssid) |
| 4573 | return cssid->id; |
| 4574 | return 0; |
| 4575 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 4576 | EXPORT_SYMBOL_GPL(css_id); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4577 | |
| 4578 | unsigned short css_depth(struct cgroup_subsys_state *css) |
| 4579 | { |
KAMEZAWA Hiroyuki | 7f0f154 | 2010-05-11 14:06:58 -0700 | [diff] [blame] | 4580 | struct css_id *cssid; |
| 4581 | |
| 4582 | cssid = rcu_dereference_check(css->id, |
| 4583 | rcu_read_lock_held() || atomic_read(&css->refcnt)); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4584 | |
| 4585 | if (cssid) |
| 4586 | return cssid->depth; |
| 4587 | return 0; |
| 4588 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 4589 | EXPORT_SYMBOL_GPL(css_depth); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4590 | |
KAMEZAWA Hiroyuki | 747388d | 2010-05-11 14:06:59 -0700 | [diff] [blame] | 4591 | /** |
| 4592 | * css_is_ancestor - test "root" css is an ancestor of "child" |
| 4593 | * @child: the css to be tested. |
| 4594 | * @root: the css supporsed to be an ancestor of the child. |
| 4595 | * |
| 4596 | * Returns true if "root" is an ancestor of "child" in its hierarchy. Because |
| 4597 | * this function reads css->id, this use rcu_dereference() and rcu_read_lock(). |
| 4598 | * But, considering usual usage, the csses should be valid objects after test. |
| 4599 | * Assuming that the caller will do some action to the child if this returns |
| 4600 | * returns true, the caller must take "child";s reference count. |
| 4601 | * If "child" is valid object and this returns true, "root" is valid, too. |
| 4602 | */ |
| 4603 | |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4604 | bool css_is_ancestor(struct cgroup_subsys_state *child, |
KAMEZAWA Hiroyuki | 0b7f569 | 2009-04-02 16:57:38 -0700 | [diff] [blame] | 4605 | const struct cgroup_subsys_state *root) |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4606 | { |
KAMEZAWA Hiroyuki | 747388d | 2010-05-11 14:06:59 -0700 | [diff] [blame] | 4607 | struct css_id *child_id; |
| 4608 | struct css_id *root_id; |
| 4609 | bool ret = true; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4610 | |
KAMEZAWA Hiroyuki | 747388d | 2010-05-11 14:06:59 -0700 | [diff] [blame] | 4611 | rcu_read_lock(); |
| 4612 | child_id = rcu_dereference(child->id); |
| 4613 | root_id = rcu_dereference(root->id); |
| 4614 | if (!child_id |
| 4615 | || !root_id |
| 4616 | || (child_id->depth < root_id->depth) |
| 4617 | || (child_id->stack[root_id->depth] != root_id->id)) |
| 4618 | ret = false; |
| 4619 | rcu_read_unlock(); |
| 4620 | return ret; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4621 | } |
| 4622 | |
| 4623 | static void __free_css_id_cb(struct rcu_head *head) |
| 4624 | { |
| 4625 | struct css_id *id; |
| 4626 | |
| 4627 | id = container_of(head, struct css_id, rcu_head); |
| 4628 | kfree(id); |
| 4629 | } |
| 4630 | |
| 4631 | void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) |
| 4632 | { |
| 4633 | struct css_id *id = css->id; |
| 4634 | /* When this is called before css_id initialization, id can be NULL */ |
| 4635 | if (!id) |
| 4636 | return; |
| 4637 | |
| 4638 | BUG_ON(!ss->use_id); |
| 4639 | |
| 4640 | rcu_assign_pointer(id->css, NULL); |
| 4641 | rcu_assign_pointer(css->id, NULL); |
| 4642 | spin_lock(&ss->id_lock); |
| 4643 | idr_remove(&ss->idr, id->id); |
| 4644 | spin_unlock(&ss->id_lock); |
| 4645 | call_rcu(&id->rcu_head, __free_css_id_cb); |
| 4646 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 4647 | EXPORT_SYMBOL_GPL(free_css_id); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4648 | |
| 4649 | /* |
| 4650 | * This is called by init or create(). Then, calls to this function are |
| 4651 | * always serialized (By cgroup_mutex() at create()). |
| 4652 | */ |
| 4653 | |
| 4654 | static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth) |
| 4655 | { |
| 4656 | struct css_id *newid; |
| 4657 | int myid, error, size; |
| 4658 | |
| 4659 | BUG_ON(!ss->use_id); |
| 4660 | |
| 4661 | size = sizeof(*newid) + sizeof(unsigned short) * (depth + 1); |
| 4662 | newid = kzalloc(size, GFP_KERNEL); |
| 4663 | if (!newid) |
| 4664 | return ERR_PTR(-ENOMEM); |
| 4665 | /* get id */ |
| 4666 | if (unlikely(!idr_pre_get(&ss->idr, GFP_KERNEL))) { |
| 4667 | error = -ENOMEM; |
| 4668 | goto err_out; |
| 4669 | } |
| 4670 | spin_lock(&ss->id_lock); |
| 4671 | /* Don't use 0. allocates an ID of 1-65535 */ |
| 4672 | error = idr_get_new_above(&ss->idr, newid, 1, &myid); |
| 4673 | spin_unlock(&ss->id_lock); |
| 4674 | |
| 4675 | /* Returns error when there are no free spaces for new ID.*/ |
| 4676 | if (error) { |
| 4677 | error = -ENOSPC; |
| 4678 | goto err_out; |
| 4679 | } |
| 4680 | if (myid > CSS_ID_MAX) |
| 4681 | goto remove_idr; |
| 4682 | |
| 4683 | newid->id = myid; |
| 4684 | newid->depth = depth; |
| 4685 | return newid; |
| 4686 | remove_idr: |
| 4687 | error = -ENOSPC; |
| 4688 | spin_lock(&ss->id_lock); |
| 4689 | idr_remove(&ss->idr, myid); |
| 4690 | spin_unlock(&ss->id_lock); |
| 4691 | err_out: |
| 4692 | kfree(newid); |
| 4693 | return ERR_PTR(error); |
| 4694 | |
| 4695 | } |
| 4696 | |
Ben Blum | e6a1105 | 2010-03-10 15:22:09 -0800 | [diff] [blame] | 4697 | static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, |
| 4698 | struct cgroup_subsys_state *rootcss) |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4699 | { |
| 4700 | struct css_id *newid; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4701 | |
| 4702 | spin_lock_init(&ss->id_lock); |
| 4703 | idr_init(&ss->idr); |
| 4704 | |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4705 | newid = get_new_cssid(ss, 0); |
| 4706 | if (IS_ERR(newid)) |
| 4707 | return PTR_ERR(newid); |
| 4708 | |
| 4709 | newid->stack[0] = newid->id; |
| 4710 | newid->css = rootcss; |
| 4711 | rootcss->id = newid; |
| 4712 | return 0; |
| 4713 | } |
| 4714 | |
| 4715 | static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, |
| 4716 | struct cgroup *child) |
| 4717 | { |
| 4718 | int subsys_id, i, depth = 0; |
| 4719 | struct cgroup_subsys_state *parent_css, *child_css; |
Li Zefan | fae9c79 | 2010-04-22 17:30:00 +0800 | [diff] [blame] | 4720 | struct css_id *child_id, *parent_id; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4721 | |
| 4722 | subsys_id = ss->subsys_id; |
| 4723 | parent_css = parent->subsys[subsys_id]; |
| 4724 | child_css = child->subsys[subsys_id]; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4725 | parent_id = parent_css->id; |
Greg Thelen | 94b3dd0 | 2010-06-04 14:15:03 -0700 | [diff] [blame] | 4726 | depth = parent_id->depth + 1; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4727 | |
| 4728 | child_id = get_new_cssid(ss, depth); |
| 4729 | if (IS_ERR(child_id)) |
| 4730 | return PTR_ERR(child_id); |
| 4731 | |
| 4732 | for (i = 0; i < depth; i++) |
| 4733 | child_id->stack[i] = parent_id->stack[i]; |
| 4734 | child_id->stack[depth] = child_id->id; |
| 4735 | /* |
| 4736 | * child_id->css pointer will be set after this cgroup is available |
| 4737 | * see cgroup_populate_dir() |
| 4738 | */ |
| 4739 | rcu_assign_pointer(child_css->id, child_id); |
| 4740 | |
| 4741 | return 0; |
| 4742 | } |
| 4743 | |
| 4744 | /** |
| 4745 | * css_lookup - lookup css by id |
| 4746 | * @ss: cgroup subsys to be looked into. |
| 4747 | * @id: the id |
| 4748 | * |
| 4749 | * Returns pointer to cgroup_subsys_state if there is valid one with id. |
| 4750 | * NULL if not. Should be called under rcu_read_lock() |
| 4751 | */ |
| 4752 | struct cgroup_subsys_state *css_lookup(struct cgroup_subsys *ss, int id) |
| 4753 | { |
| 4754 | struct css_id *cssid = NULL; |
| 4755 | |
| 4756 | BUG_ON(!ss->use_id); |
| 4757 | cssid = idr_find(&ss->idr, id); |
| 4758 | |
| 4759 | if (unlikely(!cssid)) |
| 4760 | return NULL; |
| 4761 | |
| 4762 | return rcu_dereference(cssid->css); |
| 4763 | } |
Ben Blum | 67523c4 | 2010-03-10 15:22:11 -0800 | [diff] [blame] | 4764 | EXPORT_SYMBOL_GPL(css_lookup); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 4765 | |
| 4766 | /** |
| 4767 | * css_get_next - lookup next cgroup under specified hierarchy. |
| 4768 | * @ss: pointer to subsystem |
| 4769 | * @id: current position of iteration. |
| 4770 | * @root: pointer to css. search tree under this. |
| 4771 | * @foundid: position of found object. |
| 4772 | * |
| 4773 | * Search next css under the specified hierarchy of rootid. Calling under |
| 4774 | * rcu_read_lock() is necessary. Returns NULL if it reaches the end. |
| 4775 | */ |
| 4776 | struct cgroup_subsys_state * |
| 4777 | css_get_next(struct cgroup_subsys *ss, int id, |
| 4778 | struct cgroup_subsys_state *root, int *foundid) |
| 4779 | { |
| 4780 | struct cgroup_subsys_state *ret = NULL; |
| 4781 | struct css_id *tmp; |
| 4782 | int tmpid; |
| 4783 | int rootid = css_id(root); |
| 4784 | int depth = css_depth(root); |
| 4785 | |
| 4786 | if (!rootid) |
| 4787 | return NULL; |
| 4788 | |
| 4789 | BUG_ON(!ss->use_id); |
| 4790 | /* fill start point for scan */ |
| 4791 | tmpid = id; |
| 4792 | while (1) { |
| 4793 | /* |
| 4794 | * scan next entry from bitmap(tree), tmpid is updated after |
| 4795 | * idr_get_next(). |
| 4796 | */ |
| 4797 | spin_lock(&ss->id_lock); |
| 4798 | tmp = idr_get_next(&ss->idr, &tmpid); |
| 4799 | spin_unlock(&ss->id_lock); |
| 4800 | |
| 4801 | if (!tmp) |
| 4802 | break; |
| 4803 | if (tmp->depth >= depth && tmp->stack[depth] == rootid) { |
| 4804 | ret = rcu_dereference(tmp->css); |
| 4805 | if (ret) { |
| 4806 | *foundid = tmpid; |
| 4807 | break; |
| 4808 | } |
| 4809 | } |
| 4810 | /* continue to scan from next id */ |
| 4811 | tmpid = tmpid + 1; |
| 4812 | } |
| 4813 | return ret; |
| 4814 | } |
| 4815 | |
Paul Menage | fe69343 | 2009-09-23 15:56:20 -0700 | [diff] [blame] | 4816 | #ifdef CONFIG_CGROUP_DEBUG |
| 4817 | static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss, |
| 4818 | struct cgroup *cont) |
| 4819 | { |
| 4820 | struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL); |
| 4821 | |
| 4822 | if (!css) |
| 4823 | return ERR_PTR(-ENOMEM); |
| 4824 | |
| 4825 | return css; |
| 4826 | } |
| 4827 | |
| 4828 | static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont) |
| 4829 | { |
| 4830 | kfree(cont->subsys[debug_subsys_id]); |
| 4831 | } |
| 4832 | |
| 4833 | static u64 cgroup_refcount_read(struct cgroup *cont, struct cftype *cft) |
| 4834 | { |
| 4835 | return atomic_read(&cont->count); |
| 4836 | } |
| 4837 | |
| 4838 | static u64 debug_taskcount_read(struct cgroup *cont, struct cftype *cft) |
| 4839 | { |
| 4840 | return cgroup_task_count(cont); |
| 4841 | } |
| 4842 | |
| 4843 | static u64 current_css_set_read(struct cgroup *cont, struct cftype *cft) |
| 4844 | { |
| 4845 | return (u64)(unsigned long)current->cgroups; |
| 4846 | } |
| 4847 | |
| 4848 | static u64 current_css_set_refcount_read(struct cgroup *cont, |
| 4849 | struct cftype *cft) |
| 4850 | { |
| 4851 | u64 count; |
| 4852 | |
| 4853 | rcu_read_lock(); |
| 4854 | count = atomic_read(¤t->cgroups->refcount); |
| 4855 | rcu_read_unlock(); |
| 4856 | return count; |
| 4857 | } |
| 4858 | |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 4859 | static int current_css_set_cg_links_read(struct cgroup *cont, |
| 4860 | struct cftype *cft, |
| 4861 | struct seq_file *seq) |
| 4862 | { |
| 4863 | struct cg_cgroup_link *link; |
| 4864 | struct css_set *cg; |
| 4865 | |
| 4866 | read_lock(&css_set_lock); |
| 4867 | rcu_read_lock(); |
| 4868 | cg = rcu_dereference(current->cgroups); |
| 4869 | list_for_each_entry(link, &cg->cg_links, cg_link_list) { |
| 4870 | struct cgroup *c = link->cgrp; |
| 4871 | const char *name; |
| 4872 | |
| 4873 | if (c->dentry) |
| 4874 | name = c->dentry->d_name.name; |
| 4875 | else |
| 4876 | name = "?"; |
Paul Menage | 2c6ab6d | 2009-09-23 15:56:23 -0700 | [diff] [blame] | 4877 | seq_printf(seq, "Root %d group %s\n", |
| 4878 | c->root->hierarchy_id, name); |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 4879 | } |
| 4880 | rcu_read_unlock(); |
| 4881 | read_unlock(&css_set_lock); |
| 4882 | return 0; |
| 4883 | } |
| 4884 | |
| 4885 | #define MAX_TASKS_SHOWN_PER_CSS 25 |
| 4886 | static int cgroup_css_links_read(struct cgroup *cont, |
| 4887 | struct cftype *cft, |
| 4888 | struct seq_file *seq) |
| 4889 | { |
| 4890 | struct cg_cgroup_link *link; |
| 4891 | |
| 4892 | read_lock(&css_set_lock); |
| 4893 | list_for_each_entry(link, &cont->css_sets, cgrp_link_list) { |
| 4894 | struct css_set *cg = link->cg; |
| 4895 | struct task_struct *task; |
| 4896 | int count = 0; |
| 4897 | seq_printf(seq, "css_set %p\n", cg); |
| 4898 | list_for_each_entry(task, &cg->tasks, cg_list) { |
| 4899 | if (count++ > MAX_TASKS_SHOWN_PER_CSS) { |
| 4900 | seq_puts(seq, " ...\n"); |
| 4901 | break; |
| 4902 | } else { |
| 4903 | seq_printf(seq, " task %d\n", |
| 4904 | task_pid_vnr(task)); |
| 4905 | } |
| 4906 | } |
| 4907 | } |
| 4908 | read_unlock(&css_set_lock); |
| 4909 | return 0; |
| 4910 | } |
| 4911 | |
Paul Menage | fe69343 | 2009-09-23 15:56:20 -0700 | [diff] [blame] | 4912 | static u64 releasable_read(struct cgroup *cgrp, struct cftype *cft) |
| 4913 | { |
| 4914 | return test_bit(CGRP_RELEASABLE, &cgrp->flags); |
| 4915 | } |
| 4916 | |
| 4917 | static struct cftype debug_files[] = { |
| 4918 | { |
| 4919 | .name = "cgroup_refcount", |
| 4920 | .read_u64 = cgroup_refcount_read, |
| 4921 | }, |
| 4922 | { |
| 4923 | .name = "taskcount", |
| 4924 | .read_u64 = debug_taskcount_read, |
| 4925 | }, |
| 4926 | |
| 4927 | { |
| 4928 | .name = "current_css_set", |
| 4929 | .read_u64 = current_css_set_read, |
| 4930 | }, |
| 4931 | |
| 4932 | { |
| 4933 | .name = "current_css_set_refcount", |
| 4934 | .read_u64 = current_css_set_refcount_read, |
| 4935 | }, |
| 4936 | |
| 4937 | { |
Paul Menage | 7717f7b | 2009-09-23 15:56:22 -0700 | [diff] [blame] | 4938 | .name = "current_css_set_cg_links", |
| 4939 | .read_seq_string = current_css_set_cg_links_read, |
| 4940 | }, |
| 4941 | |
| 4942 | { |
| 4943 | .name = "cgroup_css_links", |
| 4944 | .read_seq_string = cgroup_css_links_read, |
| 4945 | }, |
| 4946 | |
| 4947 | { |
Paul Menage | fe69343 | 2009-09-23 15:56:20 -0700 | [diff] [blame] | 4948 | .name = "releasable", |
| 4949 | .read_u64 = releasable_read, |
| 4950 | }, |
| 4951 | }; |
| 4952 | |
| 4953 | static int debug_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
| 4954 | { |
| 4955 | return cgroup_add_files(cont, ss, debug_files, |
| 4956 | ARRAY_SIZE(debug_files)); |
| 4957 | } |
| 4958 | |
| 4959 | struct cgroup_subsys debug_subsys = { |
| 4960 | .name = "debug", |
| 4961 | .create = debug_create, |
| 4962 | .destroy = debug_destroy, |
| 4963 | .populate = debug_populate, |
| 4964 | .subsys_id = debug_subsys_id, |
| 4965 | }; |
| 4966 | #endif /* CONFIG_CGROUP_DEBUG */ |