Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* kafstimod.c: AFS timeout daemon |
| 2 | * |
| 3 | * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved. |
| 4 | * Written by David Howells (dhowells@redhat.com) |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/sched.h> |
| 15 | #include <linux/completion.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 16 | #include <linux/freezer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include "cell.h" |
| 18 | #include "volume.h" |
| 19 | #include "kafstimod.h" |
| 20 | #include <asm/errno.h> |
| 21 | #include "internal.h" |
| 22 | |
| 23 | static DECLARE_COMPLETION(kafstimod_alive); |
| 24 | static DECLARE_COMPLETION(kafstimod_dead); |
| 25 | static DECLARE_WAIT_QUEUE_HEAD(kafstimod_sleepq); |
| 26 | static int kafstimod_die; |
| 27 | |
| 28 | static LIST_HEAD(kafstimod_list); |
| 29 | static DEFINE_SPINLOCK(kafstimod_lock); |
| 30 | |
| 31 | static int kafstimod(void *arg); |
| 32 | |
| 33 | /*****************************************************************************/ |
| 34 | /* |
| 35 | * start the timeout daemon |
| 36 | */ |
| 37 | int afs_kafstimod_start(void) |
| 38 | { |
| 39 | int ret; |
| 40 | |
| 41 | ret = kernel_thread(kafstimod, NULL, 0); |
| 42 | if (ret < 0) |
| 43 | return ret; |
| 44 | |
| 45 | wait_for_completion(&kafstimod_alive); |
| 46 | |
| 47 | return ret; |
| 48 | } /* end afs_kafstimod_start() */ |
| 49 | |
| 50 | /*****************************************************************************/ |
| 51 | /* |
| 52 | * stop the timeout daemon |
| 53 | */ |
| 54 | void afs_kafstimod_stop(void) |
| 55 | { |
| 56 | /* get rid of my daemon */ |
| 57 | kafstimod_die = 1; |
| 58 | wake_up(&kafstimod_sleepq); |
| 59 | wait_for_completion(&kafstimod_dead); |
| 60 | |
| 61 | } /* end afs_kafstimod_stop() */ |
| 62 | |
| 63 | /*****************************************************************************/ |
| 64 | /* |
| 65 | * timeout processing daemon |
| 66 | */ |
| 67 | static int kafstimod(void *arg) |
| 68 | { |
| 69 | struct afs_timer *timer; |
| 70 | |
| 71 | DECLARE_WAITQUEUE(myself, current); |
| 72 | |
| 73 | printk("kAFS: Started kafstimod %d\n", current->pid); |
| 74 | |
| 75 | daemonize("kafstimod"); |
| 76 | |
| 77 | complete(&kafstimod_alive); |
| 78 | |
| 79 | /* loop around looking for things to attend to */ |
| 80 | loop: |
| 81 | set_current_state(TASK_INTERRUPTIBLE); |
| 82 | add_wait_queue(&kafstimod_sleepq, &myself); |
| 83 | |
| 84 | for (;;) { |
| 85 | unsigned long jif; |
| 86 | signed long timeout; |
| 87 | |
| 88 | /* deal with the server being asked to die */ |
| 89 | if (kafstimod_die) { |
| 90 | remove_wait_queue(&kafstimod_sleepq, &myself); |
| 91 | _leave(""); |
| 92 | complete_and_exit(&kafstimod_dead, 0); |
| 93 | } |
| 94 | |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 95 | try_to_freeze(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | |
| 97 | /* discard pending signals */ |
| 98 | afs_discard_my_signals(); |
| 99 | |
| 100 | /* work out the time to elapse before the next event */ |
| 101 | spin_lock(&kafstimod_lock); |
| 102 | if (list_empty(&kafstimod_list)) { |
| 103 | timeout = MAX_SCHEDULE_TIMEOUT; |
| 104 | } |
| 105 | else { |
| 106 | timer = list_entry(kafstimod_list.next, |
| 107 | struct afs_timer, link); |
| 108 | timeout = timer->timo_jif; |
| 109 | jif = jiffies; |
| 110 | |
| 111 | if (time_before_eq((unsigned long) timeout, jif)) |
| 112 | goto immediate; |
| 113 | |
| 114 | else { |
| 115 | timeout = (long) timeout - (long) jiffies; |
| 116 | } |
| 117 | } |
| 118 | spin_unlock(&kafstimod_lock); |
| 119 | |
| 120 | schedule_timeout(timeout); |
| 121 | |
| 122 | set_current_state(TASK_INTERRUPTIBLE); |
| 123 | } |
| 124 | |
| 125 | /* the thing on the front of the queue needs processing |
| 126 | * - we come here with the lock held and timer pointing to the expired |
| 127 | * entry |
| 128 | */ |
| 129 | immediate: |
| 130 | remove_wait_queue(&kafstimod_sleepq, &myself); |
| 131 | set_current_state(TASK_RUNNING); |
| 132 | |
| 133 | _debug("@@@ Begin Timeout of %p", timer); |
| 134 | |
| 135 | /* dequeue the timer */ |
| 136 | list_del_init(&timer->link); |
| 137 | spin_unlock(&kafstimod_lock); |
| 138 | |
| 139 | /* call the timeout function */ |
| 140 | timer->ops->timed_out(timer); |
| 141 | |
| 142 | _debug("@@@ End Timeout"); |
| 143 | goto loop; |
| 144 | |
| 145 | } /* end kafstimod() */ |
| 146 | |
| 147 | /*****************************************************************************/ |
| 148 | /* |
| 149 | * (re-)queue a timer |
| 150 | */ |
| 151 | void afs_kafstimod_add_timer(struct afs_timer *timer, unsigned long timeout) |
| 152 | { |
| 153 | struct afs_timer *ptimer; |
| 154 | struct list_head *_p; |
| 155 | |
| 156 | _enter("%p,%lu", timer, timeout); |
| 157 | |
| 158 | spin_lock(&kafstimod_lock); |
| 159 | |
| 160 | list_del(&timer->link); |
| 161 | |
| 162 | /* the timer was deferred or reset - put it back in the queue at the |
| 163 | * right place */ |
| 164 | timer->timo_jif = jiffies + timeout; |
| 165 | |
| 166 | list_for_each(_p, &kafstimod_list) { |
| 167 | ptimer = list_entry(_p, struct afs_timer, link); |
| 168 | if (time_before(timer->timo_jif, ptimer->timo_jif)) |
| 169 | break; |
| 170 | } |
| 171 | |
| 172 | list_add_tail(&timer->link, _p); /* insert before stopping point */ |
| 173 | |
| 174 | spin_unlock(&kafstimod_lock); |
| 175 | |
| 176 | wake_up(&kafstimod_sleepq); |
| 177 | |
| 178 | _leave(""); |
| 179 | } /* end afs_kafstimod_add_timer() */ |
| 180 | |
| 181 | /*****************************************************************************/ |
| 182 | /* |
| 183 | * dequeue a timer |
| 184 | * - returns 0 if the timer was deleted or -ENOENT if it wasn't queued |
| 185 | */ |
| 186 | int afs_kafstimod_del_timer(struct afs_timer *timer) |
| 187 | { |
| 188 | int ret = 0; |
| 189 | |
| 190 | _enter("%p", timer); |
| 191 | |
| 192 | spin_lock(&kafstimod_lock); |
| 193 | |
| 194 | if (list_empty(&timer->link)) |
| 195 | ret = -ENOENT; |
| 196 | else |
| 197 | list_del_init(&timer->link); |
| 198 | |
| 199 | spin_unlock(&kafstimod_lock); |
| 200 | |
| 201 | wake_up(&kafstimod_sleepq); |
| 202 | |
| 203 | _leave(" = %d", ret); |
| 204 | return ret; |
| 205 | } /* end afs_kafstimod_del_timer() */ |