Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * An async IO implementation for Linux |
| 3 | * Written by Benjamin LaHaise <bcrl@kvack.org> |
| 4 | * |
| 5 | * Implements an efficient asynchronous io interface. |
| 6 | * |
| 7 | * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved. |
| 8 | * |
| 9 | * See ../COPYING for licensing terms. |
| 10 | */ |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/time.h> |
| 15 | #include <linux/aio_abi.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/syscalls.h> |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 18 | #include <linux/uio.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
| 20 | #define DEBUG 0 |
| 21 | |
| 22 | #include <linux/sched.h> |
| 23 | #include <linux/fs.h> |
| 24 | #include <linux/file.h> |
| 25 | #include <linux/mm.h> |
| 26 | #include <linux/mman.h> |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/timer.h> |
| 29 | #include <linux/aio.h> |
| 30 | #include <linux/highmem.h> |
| 31 | #include <linux/workqueue.h> |
| 32 | #include <linux/security.h> |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 33 | #include <linux/eventfd.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
| 35 | #include <asm/kmap_types.h> |
| 36 | #include <asm/uaccess.h> |
| 37 | #include <asm/mmu_context.h> |
| 38 | |
| 39 | #if DEBUG > 1 |
| 40 | #define dprintk printk |
| 41 | #else |
| 42 | #define dprintk(x...) do { ; } while (0) |
| 43 | #endif |
| 44 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | /*------ sysctl variables----*/ |
Zach Brown | d55b5fd | 2005-11-07 00:59:31 -0800 | [diff] [blame] | 46 | static DEFINE_SPINLOCK(aio_nr_lock); |
| 47 | unsigned long aio_nr; /* current system wide number of aio requests */ |
| 48 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | /*----end sysctl variables---*/ |
| 50 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 51 | static struct kmem_cache *kiocb_cachep; |
| 52 | static struct kmem_cache *kioctx_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | |
| 54 | static struct workqueue_struct *aio_wq; |
| 55 | |
| 56 | /* Used for rare fput completion. */ |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 57 | static void aio_fput_routine(struct work_struct *); |
| 58 | static DECLARE_WORK(fput_work, aio_fput_routine); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | |
| 60 | static DEFINE_SPINLOCK(fput_lock); |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 61 | static LIST_HEAD(fput_head); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 63 | static void aio_kick_handler(struct work_struct *); |
Sébastien Dugu | c016e22 | 2005-06-28 20:44:59 -0700 | [diff] [blame] | 64 | static void aio_queue_work(struct kioctx *); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
| 66 | /* aio_setup |
| 67 | * Creates the slab caches used by the aio routines, panic on |
| 68 | * failure as this is done early during the boot sequence. |
| 69 | */ |
| 70 | static int __init aio_setup(void) |
| 71 | { |
Christoph Lameter | 0a31bd5 | 2007-05-06 14:49:57 -0700 | [diff] [blame] | 72 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
| 73 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
| 75 | aio_wq = create_workqueue("aio"); |
| 76 | |
| 77 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
| 78 | |
| 79 | return 0; |
| 80 | } |
| 81 | |
| 82 | static void aio_free_ring(struct kioctx *ctx) |
| 83 | { |
| 84 | struct aio_ring_info *info = &ctx->ring_info; |
| 85 | long i; |
| 86 | |
| 87 | for (i=0; i<info->nr_pages; i++) |
| 88 | put_page(info->ring_pages[i]); |
| 89 | |
| 90 | if (info->mmap_size) { |
| 91 | down_write(&ctx->mm->mmap_sem); |
| 92 | do_munmap(ctx->mm, info->mmap_base, info->mmap_size); |
| 93 | up_write(&ctx->mm->mmap_sem); |
| 94 | } |
| 95 | |
| 96 | if (info->ring_pages && info->ring_pages != info->internal_pages) |
| 97 | kfree(info->ring_pages); |
| 98 | info->ring_pages = NULL; |
| 99 | info->nr = 0; |
| 100 | } |
| 101 | |
| 102 | static int aio_setup_ring(struct kioctx *ctx) |
| 103 | { |
| 104 | struct aio_ring *ring; |
| 105 | struct aio_ring_info *info = &ctx->ring_info; |
| 106 | unsigned nr_events = ctx->max_reqs; |
| 107 | unsigned long size; |
| 108 | int nr_pages; |
| 109 | |
| 110 | /* Compensate for the ring buffer's head/tail overlap entry */ |
| 111 | nr_events += 2; /* 1 is required, 2 for good luck */ |
| 112 | |
| 113 | size = sizeof(struct aio_ring); |
| 114 | size += sizeof(struct io_event) * nr_events; |
| 115 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
| 116 | |
| 117 | if (nr_pages < 0) |
| 118 | return -EINVAL; |
| 119 | |
| 120 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
| 121 | |
| 122 | info->nr = 0; |
| 123 | info->ring_pages = info->internal_pages; |
| 124 | if (nr_pages > AIO_RING_PAGES) { |
Oliver Neukum | 11b0b5a | 2006-03-25 03:08:13 -0800 | [diff] [blame] | 125 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | if (!info->ring_pages) |
| 127 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | } |
| 129 | |
| 130 | info->mmap_size = nr_pages * PAGE_SIZE; |
| 131 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
| 132 | down_write(&ctx->mm->mmap_sem); |
| 133 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, |
Robert P. J. Day | e10a443 | 2007-02-10 01:42:56 -0800 | [diff] [blame] | 134 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | 0); |
| 136 | if (IS_ERR((void *)info->mmap_base)) { |
| 137 | up_write(&ctx->mm->mmap_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | info->mmap_size = 0; |
| 139 | aio_free_ring(ctx); |
| 140 | return -EAGAIN; |
| 141 | } |
| 142 | |
| 143 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
| 144 | info->nr_pages = get_user_pages(current, ctx->mm, |
| 145 | info->mmap_base, nr_pages, |
| 146 | 1, 0, info->ring_pages, NULL); |
| 147 | up_write(&ctx->mm->mmap_sem); |
| 148 | |
| 149 | if (unlikely(info->nr_pages != nr_pages)) { |
| 150 | aio_free_ring(ctx); |
| 151 | return -EAGAIN; |
| 152 | } |
| 153 | |
| 154 | ctx->user_id = info->mmap_base; |
| 155 | |
| 156 | info->nr = nr_events; /* trusted copy */ |
| 157 | |
| 158 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
| 159 | ring->nr = nr_events; /* user copy */ |
| 160 | ring->id = ctx->user_id; |
| 161 | ring->head = ring->tail = 0; |
| 162 | ring->magic = AIO_RING_MAGIC; |
| 163 | ring->compat_features = AIO_RING_COMPAT_FEATURES; |
| 164 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; |
| 165 | ring->header_length = sizeof(struct aio_ring); |
| 166 | kunmap_atomic(ring, KM_USER0); |
| 167 | |
| 168 | return 0; |
| 169 | } |
| 170 | |
| 171 | |
| 172 | /* aio_ring_event: returns a pointer to the event at the given index from |
| 173 | * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); |
| 174 | */ |
| 175 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
| 176 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) |
| 177 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) |
| 178 | |
| 179 | #define aio_ring_event(info, nr, km) ({ \ |
| 180 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ |
| 181 | struct io_event *__event; \ |
| 182 | __event = kmap_atomic( \ |
| 183 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ |
| 184 | __event += pos % AIO_EVENTS_PER_PAGE; \ |
| 185 | __event; \ |
| 186 | }) |
| 187 | |
| 188 | #define put_aio_ring_event(event, km) do { \ |
| 189 | struct io_event *__event = (event); \ |
| 190 | (void)__event; \ |
| 191 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ |
| 192 | } while(0) |
| 193 | |
| 194 | /* ioctx_alloc |
| 195 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
| 196 | */ |
| 197 | static struct kioctx *ioctx_alloc(unsigned nr_events) |
| 198 | { |
| 199 | struct mm_struct *mm; |
| 200 | struct kioctx *ctx; |
| 201 | |
| 202 | /* Prevent overflows */ |
| 203 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
| 204 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
| 205 | pr_debug("ENOMEM: nr_events too high\n"); |
| 206 | return ERR_PTR(-EINVAL); |
| 207 | } |
| 208 | |
Zach Brown | d55b5fd | 2005-11-07 00:59:31 -0800 | [diff] [blame] | 209 | if ((unsigned long)nr_events > aio_max_nr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | return ERR_PTR(-EAGAIN); |
| 211 | |
Robert P. J. Day | c376222 | 2007-02-10 01:45:03 -0800 | [diff] [blame] | 212 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | if (!ctx) |
| 214 | return ERR_PTR(-ENOMEM); |
| 215 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | ctx->max_reqs = nr_events; |
| 217 | mm = ctx->mm = current->mm; |
| 218 | atomic_inc(&mm->mm_count); |
| 219 | |
| 220 | atomic_set(&ctx->users, 1); |
| 221 | spin_lock_init(&ctx->ctx_lock); |
| 222 | spin_lock_init(&ctx->ring_info.ring_lock); |
| 223 | init_waitqueue_head(&ctx->wait); |
| 224 | |
| 225 | INIT_LIST_HEAD(&ctx->active_reqs); |
| 226 | INIT_LIST_HEAD(&ctx->run_list); |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 227 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | |
| 229 | if (aio_setup_ring(ctx) < 0) |
| 230 | goto out_freectx; |
| 231 | |
| 232 | /* limit the number of system wide aios */ |
Zach Brown | d55b5fd | 2005-11-07 00:59:31 -0800 | [diff] [blame] | 233 | spin_lock(&aio_nr_lock); |
| 234 | if (aio_nr + ctx->max_reqs > aio_max_nr || |
| 235 | aio_nr + ctx->max_reqs < aio_nr) |
| 236 | ctx->max_reqs = 0; |
| 237 | else |
| 238 | aio_nr += ctx->max_reqs; |
| 239 | spin_unlock(&aio_nr_lock); |
| 240 | if (ctx->max_reqs == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | goto out_cleanup; |
| 242 | |
| 243 | /* now link into global list. kludge. FIXME */ |
| 244 | write_lock(&mm->ioctx_list_lock); |
| 245 | ctx->next = mm->ioctx_list; |
| 246 | mm->ioctx_list = ctx; |
| 247 | write_unlock(&mm->ioctx_list_lock); |
| 248 | |
| 249 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
| 250 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
| 251 | return ctx; |
| 252 | |
| 253 | out_cleanup: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 254 | __put_ioctx(ctx); |
| 255 | return ERR_PTR(-EAGAIN); |
| 256 | |
| 257 | out_freectx: |
| 258 | mmdrop(mm); |
| 259 | kmem_cache_free(kioctx_cachep, ctx); |
| 260 | ctx = ERR_PTR(-ENOMEM); |
| 261 | |
| 262 | dprintk("aio: error allocating ioctx %p\n", ctx); |
| 263 | return ctx; |
| 264 | } |
| 265 | |
| 266 | /* aio_cancel_all |
| 267 | * Cancels all outstanding aio requests on an aio context. Used |
| 268 | * when the processes owning a context have all exited to encourage |
| 269 | * the rapid destruction of the kioctx. |
| 270 | */ |
| 271 | static void aio_cancel_all(struct kioctx *ctx) |
| 272 | { |
| 273 | int (*cancel)(struct kiocb *, struct io_event *); |
| 274 | struct io_event res; |
| 275 | spin_lock_irq(&ctx->ctx_lock); |
| 276 | ctx->dead = 1; |
| 277 | while (!list_empty(&ctx->active_reqs)) { |
| 278 | struct list_head *pos = ctx->active_reqs.next; |
| 279 | struct kiocb *iocb = list_kiocb(pos); |
| 280 | list_del_init(&iocb->ki_list); |
| 281 | cancel = iocb->ki_cancel; |
| 282 | kiocbSetCancelled(iocb); |
| 283 | if (cancel) { |
| 284 | iocb->ki_users++; |
| 285 | spin_unlock_irq(&ctx->ctx_lock); |
| 286 | cancel(iocb, &res); |
| 287 | spin_lock_irq(&ctx->ctx_lock); |
| 288 | } |
| 289 | } |
| 290 | spin_unlock_irq(&ctx->ctx_lock); |
| 291 | } |
| 292 | |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 293 | static void wait_for_all_aios(struct kioctx *ctx) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | { |
| 295 | struct task_struct *tsk = current; |
| 296 | DECLARE_WAITQUEUE(wait, tsk); |
| 297 | |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 298 | spin_lock_irq(&ctx->ctx_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | if (!ctx->reqs_active) |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 300 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | |
| 302 | add_wait_queue(&ctx->wait, &wait); |
| 303 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
| 304 | while (ctx->reqs_active) { |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 305 | spin_unlock_irq(&ctx->ctx_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | schedule(); |
| 307 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 308 | spin_lock_irq(&ctx->ctx_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | } |
| 310 | __set_task_state(tsk, TASK_RUNNING); |
| 311 | remove_wait_queue(&ctx->wait, &wait); |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 312 | |
| 313 | out: |
| 314 | spin_unlock_irq(&ctx->ctx_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | } |
| 316 | |
| 317 | /* wait_on_sync_kiocb: |
| 318 | * Waits on the given sync kiocb to complete. |
| 319 | */ |
| 320 | ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb) |
| 321 | { |
| 322 | while (iocb->ki_users) { |
| 323 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 324 | if (!iocb->ki_users) |
| 325 | break; |
| 326 | schedule(); |
| 327 | } |
| 328 | __set_current_state(TASK_RUNNING); |
| 329 | return iocb->ki_user_data; |
| 330 | } |
| 331 | |
| 332 | /* exit_aio: called when the last user of mm goes away. At this point, |
| 333 | * there is no way for any new requests to be submited or any of the |
| 334 | * io_* syscalls to be called on the context. However, there may be |
| 335 | * outstanding requests which hold references to the context; as they |
| 336 | * go away, they will call put_ioctx and release any pinned memory |
| 337 | * associated with the request (held via struct page * references). |
| 338 | */ |
| 339 | void fastcall exit_aio(struct mm_struct *mm) |
| 340 | { |
| 341 | struct kioctx *ctx = mm->ioctx_list; |
| 342 | mm->ioctx_list = NULL; |
| 343 | while (ctx) { |
| 344 | struct kioctx *next = ctx->next; |
| 345 | ctx->next = NULL; |
| 346 | aio_cancel_all(ctx); |
| 347 | |
| 348 | wait_for_all_aios(ctx); |
| 349 | /* |
Andrew Morton | a9df62c | 2007-05-09 02:33:54 -0700 | [diff] [blame] | 350 | * Ensure we don't leave the ctx on the aio_wq |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | */ |
Oleg Nesterov | 28e53bd | 2007-05-09 02:34:22 -0700 | [diff] [blame] | 352 | cancel_work_sync(&ctx->wq.work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | |
| 354 | if (1 != atomic_read(&ctx->users)) |
| 355 | printk(KERN_DEBUG |
| 356 | "exit_aio:ioctx still alive: %d %d %d\n", |
| 357 | atomic_read(&ctx->users), ctx->dead, |
| 358 | ctx->reqs_active); |
| 359 | put_ioctx(ctx); |
| 360 | ctx = next; |
| 361 | } |
| 362 | } |
| 363 | |
| 364 | /* __put_ioctx |
| 365 | * Called when the last user of an aio context has gone away, |
| 366 | * and the struct needs to be freed. |
| 367 | */ |
| 368 | void fastcall __put_ioctx(struct kioctx *ctx) |
| 369 | { |
| 370 | unsigned nr_events = ctx->max_reqs; |
| 371 | |
Eric Sesterhenn | 93e06b4 | 2006-11-30 05:29:23 +0100 | [diff] [blame] | 372 | BUG_ON(ctx->reqs_active); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | |
| 374 | cancel_delayed_work(&ctx->wq); |
Oleg Nesterov | 28e53bd | 2007-05-09 02:34:22 -0700 | [diff] [blame] | 375 | cancel_work_sync(&ctx->wq.work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | aio_free_ring(ctx); |
| 377 | mmdrop(ctx->mm); |
| 378 | ctx->mm = NULL; |
| 379 | pr_debug("__put_ioctx: freeing %p\n", ctx); |
| 380 | kmem_cache_free(kioctx_cachep, ctx); |
| 381 | |
Zach Brown | d55b5fd | 2005-11-07 00:59:31 -0800 | [diff] [blame] | 382 | if (nr_events) { |
| 383 | spin_lock(&aio_nr_lock); |
| 384 | BUG_ON(aio_nr - nr_events > aio_nr); |
| 385 | aio_nr -= nr_events; |
| 386 | spin_unlock(&aio_nr_lock); |
| 387 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | } |
| 389 | |
| 390 | /* aio_get_req |
| 391 | * Allocate a slot for an aio request. Increments the users count |
| 392 | * of the kioctx so that the kioctx stays around until all requests are |
| 393 | * complete. Returns NULL if no requests are free. |
| 394 | * |
| 395 | * Returns with kiocb->users set to 2. The io submit code path holds |
| 396 | * an extra reference while submitting the i/o. |
| 397 | * This prevents races between the aio code path referencing the |
| 398 | * req (after submitting it) and aio_complete() freeing the req. |
| 399 | */ |
| 400 | static struct kiocb *FASTCALL(__aio_get_req(struct kioctx *ctx)); |
| 401 | static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx) |
| 402 | { |
| 403 | struct kiocb *req = NULL; |
| 404 | struct aio_ring *ring; |
| 405 | int okay = 0; |
| 406 | |
| 407 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
| 408 | if (unlikely(!req)) |
| 409 | return NULL; |
| 410 | |
Zach Brown | 4faa528 | 2005-10-17 16:43:33 -0700 | [diff] [blame] | 411 | req->ki_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 412 | req->ki_users = 2; |
| 413 | req->ki_key = 0; |
| 414 | req->ki_ctx = ctx; |
| 415 | req->ki_cancel = NULL; |
| 416 | req->ki_retry = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | req->ki_dtor = NULL; |
| 418 | req->private = NULL; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 419 | req->ki_iovec = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | INIT_LIST_HEAD(&req->ki_run_list); |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 421 | req->ki_eventfd = ERR_PTR(-EINVAL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | |
| 423 | /* Check if the completion queue has enough free space to |
| 424 | * accept an event from this io. |
| 425 | */ |
| 426 | spin_lock_irq(&ctx->ctx_lock); |
| 427 | ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0); |
| 428 | if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) { |
| 429 | list_add(&req->ki_list, &ctx->active_reqs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | ctx->reqs_active++; |
| 431 | okay = 1; |
| 432 | } |
| 433 | kunmap_atomic(ring, KM_USER0); |
| 434 | spin_unlock_irq(&ctx->ctx_lock); |
| 435 | |
| 436 | if (!okay) { |
| 437 | kmem_cache_free(kiocb_cachep, req); |
| 438 | req = NULL; |
| 439 | } |
| 440 | |
| 441 | return req; |
| 442 | } |
| 443 | |
| 444 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
| 445 | { |
| 446 | struct kiocb *req; |
| 447 | /* Handle a potential starvation case -- should be exceedingly rare as |
| 448 | * requests will be stuck on fput_head only if the aio_fput_routine is |
| 449 | * delayed and the requests were the last user of the struct file. |
| 450 | */ |
| 451 | req = __aio_get_req(ctx); |
| 452 | if (unlikely(NULL == req)) { |
| 453 | aio_fput_routine(NULL); |
| 454 | req = __aio_get_req(ctx); |
| 455 | } |
| 456 | return req; |
| 457 | } |
| 458 | |
| 459 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
| 460 | { |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 461 | assert_spin_locked(&ctx->ctx_lock); |
| 462 | |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 463 | if (!IS_ERR(req->ki_eventfd)) |
| 464 | fput(req->ki_eventfd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | if (req->ki_dtor) |
| 466 | req->ki_dtor(req); |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 467 | if (req->ki_iovec != &req->ki_inline_vec) |
| 468 | kfree(req->ki_iovec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | kmem_cache_free(kiocb_cachep, req); |
| 470 | ctx->reqs_active--; |
| 471 | |
| 472 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
| 473 | wake_up(&ctx->wait); |
| 474 | } |
| 475 | |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 476 | static void aio_fput_routine(struct work_struct *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | { |
| 478 | spin_lock_irq(&fput_lock); |
| 479 | while (likely(!list_empty(&fput_head))) { |
| 480 | struct kiocb *req = list_kiocb(fput_head.next); |
| 481 | struct kioctx *ctx = req->ki_ctx; |
| 482 | |
| 483 | list_del(&req->ki_list); |
| 484 | spin_unlock_irq(&fput_lock); |
| 485 | |
| 486 | /* Complete the fput */ |
| 487 | __fput(req->ki_filp); |
| 488 | |
| 489 | /* Link the iocb into the context's free list */ |
| 490 | spin_lock_irq(&ctx->ctx_lock); |
| 491 | really_put_req(ctx, req); |
| 492 | spin_unlock_irq(&ctx->ctx_lock); |
| 493 | |
| 494 | put_ioctx(ctx); |
| 495 | spin_lock_irq(&fput_lock); |
| 496 | } |
| 497 | spin_unlock_irq(&fput_lock); |
| 498 | } |
| 499 | |
| 500 | /* __aio_put_req |
| 501 | * Returns true if this put was the last user of the request. |
| 502 | */ |
| 503 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
| 504 | { |
| 505 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n", |
| 506 | req, atomic_read(&req->ki_filp->f_count)); |
| 507 | |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 508 | assert_spin_locked(&ctx->ctx_lock); |
| 509 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | req->ki_users --; |
Eric Sesterhenn | 93e06b4 | 2006-11-30 05:29:23 +0100 | [diff] [blame] | 511 | BUG_ON(req->ki_users < 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | if (likely(req->ki_users)) |
| 513 | return 0; |
| 514 | list_del(&req->ki_list); /* remove from active_reqs */ |
| 515 | req->ki_cancel = NULL; |
| 516 | req->ki_retry = NULL; |
| 517 | |
| 518 | /* Must be done under the lock to serialise against cancellation. |
| 519 | * Call this aio_fput as it duplicates fput via the fput_work. |
| 520 | */ |
Nick Piggin | 095975d | 2006-01-08 01:02:19 -0800 | [diff] [blame] | 521 | if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | get_ioctx(ctx); |
| 523 | spin_lock(&fput_lock); |
| 524 | list_add(&req->ki_list, &fput_head); |
| 525 | spin_unlock(&fput_lock); |
| 526 | queue_work(aio_wq, &fput_work); |
| 527 | } else |
| 528 | really_put_req(ctx, req); |
| 529 | return 1; |
| 530 | } |
| 531 | |
| 532 | /* aio_put_req |
| 533 | * Returns true if this put was the last user of the kiocb, |
| 534 | * false if the request is still in use. |
| 535 | */ |
| 536 | int fastcall aio_put_req(struct kiocb *req) |
| 537 | { |
| 538 | struct kioctx *ctx = req->ki_ctx; |
| 539 | int ret; |
| 540 | spin_lock_irq(&ctx->ctx_lock); |
| 541 | ret = __aio_put_req(ctx, req); |
| 542 | spin_unlock_irq(&ctx->ctx_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 543 | return ret; |
| 544 | } |
| 545 | |
| 546 | /* Lookup an ioctx id. ioctx_list is lockless for reads. |
| 547 | * FIXME: this is O(n) and is only suitable for development. |
| 548 | */ |
| 549 | struct kioctx *lookup_ioctx(unsigned long ctx_id) |
| 550 | { |
| 551 | struct kioctx *ioctx; |
| 552 | struct mm_struct *mm; |
| 553 | |
| 554 | mm = current->mm; |
| 555 | read_lock(&mm->ioctx_list_lock); |
| 556 | for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next) |
| 557 | if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) { |
| 558 | get_ioctx(ioctx); |
| 559 | break; |
| 560 | } |
| 561 | read_unlock(&mm->ioctx_list_lock); |
| 562 | |
| 563 | return ioctx; |
| 564 | } |
| 565 | |
| 566 | /* |
| 567 | * use_mm |
| 568 | * Makes the calling kernel thread take on the specified |
| 569 | * mm context. |
| 570 | * Called by the retry thread execute retries within the |
| 571 | * iocb issuer's mm context, so that copy_from/to_user |
| 572 | * operations work seamlessly for aio. |
| 573 | * (Note: this routine is intended to be called only |
| 574 | * from a kernel thread context) |
| 575 | */ |
| 576 | static void use_mm(struct mm_struct *mm) |
| 577 | { |
| 578 | struct mm_struct *active_mm; |
| 579 | struct task_struct *tsk = current; |
| 580 | |
| 581 | task_lock(tsk); |
| 582 | tsk->flags |= PF_BORROWED_MM; |
| 583 | active_mm = tsk->active_mm; |
| 584 | atomic_inc(&mm->mm_count); |
| 585 | tsk->mm = mm; |
| 586 | tsk->active_mm = mm; |
Paolo 'Blaisorblade' Giarrusso | 1e40cd3 | 2005-09-03 15:57:25 -0700 | [diff] [blame] | 587 | /* |
| 588 | * Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise |
| 589 | * it won't work. Update it accordingly if you change it here |
| 590 | */ |
Jeremy Fitzhardinge | 90aef12 | 2006-12-13 00:34:49 -0800 | [diff] [blame] | 591 | switch_mm(active_mm, mm, tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | task_unlock(tsk); |
| 593 | |
| 594 | mmdrop(active_mm); |
| 595 | } |
| 596 | |
| 597 | /* |
| 598 | * unuse_mm |
| 599 | * Reverses the effect of use_mm, i.e. releases the |
| 600 | * specified mm context which was earlier taken on |
| 601 | * by the calling kernel thread |
| 602 | * (Note: this routine is intended to be called only |
| 603 | * from a kernel thread context) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 604 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 605 | static void unuse_mm(struct mm_struct *mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 606 | { |
| 607 | struct task_struct *tsk = current; |
| 608 | |
| 609 | task_lock(tsk); |
| 610 | tsk->flags &= ~PF_BORROWED_MM; |
| 611 | tsk->mm = NULL; |
| 612 | /* active_mm is still 'mm' */ |
| 613 | enter_lazy_tlb(mm, tsk); |
| 614 | task_unlock(tsk); |
| 615 | } |
| 616 | |
| 617 | /* |
| 618 | * Queue up a kiocb to be retried. Assumes that the kiocb |
| 619 | * has already been marked as kicked, and places it on |
| 620 | * the retry run list for the corresponding ioctx, if it |
| 621 | * isn't already queued. Returns 1 if it actually queued |
| 622 | * the kiocb (to tell the caller to activate the work |
| 623 | * queue to process it), or 0, if it found that it was |
| 624 | * already queued. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | */ |
| 626 | static inline int __queue_kicked_iocb(struct kiocb *iocb) |
| 627 | { |
| 628 | struct kioctx *ctx = iocb->ki_ctx; |
| 629 | |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 630 | assert_spin_locked(&ctx->ctx_lock); |
| 631 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | if (list_empty(&iocb->ki_run_list)) { |
| 633 | list_add_tail(&iocb->ki_run_list, |
| 634 | &ctx->run_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | return 1; |
| 636 | } |
| 637 | return 0; |
| 638 | } |
| 639 | |
| 640 | /* aio_run_iocb |
| 641 | * This is the core aio execution routine. It is |
| 642 | * invoked both for initial i/o submission and |
| 643 | * subsequent retries via the aio_kick_handler. |
| 644 | * Expects to be invoked with iocb->ki_ctx->lock |
Andreas Mohr | d6e05ed | 2006-06-26 18:35:02 +0200 | [diff] [blame] | 645 | * already held. The lock is released and reacquired |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | * as needed during processing. |
| 647 | * |
| 648 | * Calls the iocb retry method (already setup for the |
| 649 | * iocb on initial submission) for operation specific |
| 650 | * handling, but takes care of most of common retry |
| 651 | * execution details for a given iocb. The retry method |
| 652 | * needs to be non-blocking as far as possible, to avoid |
| 653 | * holding up other iocbs waiting to be serviced by the |
| 654 | * retry kernel thread. |
| 655 | * |
| 656 | * The trickier parts in this code have to do with |
| 657 | * ensuring that only one retry instance is in progress |
| 658 | * for a given iocb at any time. Providing that guarantee |
| 659 | * simplifies the coding of individual aio operations as |
| 660 | * it avoids various potential races. |
| 661 | */ |
| 662 | static ssize_t aio_run_iocb(struct kiocb *iocb) |
| 663 | { |
| 664 | struct kioctx *ctx = iocb->ki_ctx; |
| 665 | ssize_t (*retry)(struct kiocb *); |
| 666 | ssize_t ret; |
| 667 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 668 | if (!(retry = iocb->ki_retry)) { |
| 669 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
| 670 | return 0; |
| 671 | } |
| 672 | |
| 673 | /* |
| 674 | * We don't want the next retry iteration for this |
| 675 | * operation to start until this one has returned and |
| 676 | * updated the iocb state. However, wait_queue functions |
| 677 | * can trigger a kick_iocb from interrupt context in the |
| 678 | * meantime, indicating that data is available for the next |
| 679 | * iteration. We want to remember that and enable the |
| 680 | * next retry iteration _after_ we are through with |
| 681 | * this one. |
| 682 | * |
| 683 | * So, in order to be able to register a "kick", but |
| 684 | * prevent it from being queued now, we clear the kick |
| 685 | * flag, but make the kick code *think* that the iocb is |
| 686 | * still on the run list until we are actually done. |
| 687 | * When we are done with this iteration, we check if |
| 688 | * the iocb was kicked in the meantime and if so, queue |
| 689 | * it up afresh. |
| 690 | */ |
| 691 | |
| 692 | kiocbClearKicked(iocb); |
| 693 | |
| 694 | /* |
| 695 | * This is so that aio_complete knows it doesn't need to |
| 696 | * pull the iocb off the run list (We can't just call |
| 697 | * INIT_LIST_HEAD because we don't want a kick_iocb to |
| 698 | * queue this on the run list yet) |
| 699 | */ |
| 700 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
| 701 | spin_unlock_irq(&ctx->ctx_lock); |
| 702 | |
| 703 | /* Quit retrying if the i/o has been cancelled */ |
| 704 | if (kiocbIsCancelled(iocb)) { |
| 705 | ret = -EINTR; |
| 706 | aio_complete(iocb, ret, 0); |
| 707 | /* must not access the iocb after this */ |
| 708 | goto out; |
| 709 | } |
| 710 | |
| 711 | /* |
| 712 | * Now we are all set to call the retry method in async |
| 713 | * context. By setting this thread's io_wait context |
| 714 | * to point to the wait queue entry inside the currently |
| 715 | * running iocb for the duration of the retry, we ensure |
| 716 | * that async notification wakeups are queued by the |
| 717 | * operation instead of blocking waits, and when notified, |
| 718 | * cause the iocb to be kicked for continuation (through |
| 719 | * the aio_wake_function callback). |
| 720 | */ |
| 721 | BUG_ON(current->io_wait != NULL); |
| 722 | current->io_wait = &iocb->ki_wait; |
| 723 | ret = retry(iocb); |
| 724 | current->io_wait = NULL; |
| 725 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 726 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
| 727 | BUG_ON(!list_empty(&iocb->ki_wait.task_list)); |
| 728 | aio_complete(iocb, ret, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | } |
| 730 | out: |
| 731 | spin_lock_irq(&ctx->ctx_lock); |
| 732 | |
| 733 | if (-EIOCBRETRY == ret) { |
| 734 | /* |
| 735 | * OK, now that we are done with this iteration |
| 736 | * and know that there is more left to go, |
| 737 | * this is where we let go so that a subsequent |
| 738 | * "kick" can start the next iteration |
| 739 | */ |
| 740 | |
| 741 | /* will make __queue_kicked_iocb succeed from here on */ |
| 742 | INIT_LIST_HEAD(&iocb->ki_run_list); |
| 743 | /* we must queue the next iteration ourselves, if it |
| 744 | * has already been kicked */ |
| 745 | if (kiocbIsKicked(iocb)) { |
| 746 | __queue_kicked_iocb(iocb); |
Sébastien Dugu | c016e22 | 2005-06-28 20:44:59 -0700 | [diff] [blame] | 747 | |
| 748 | /* |
| 749 | * __queue_kicked_iocb will always return 1 here, because |
| 750 | * iocb->ki_run_list is empty at this point so it should |
| 751 | * be safe to unconditionally queue the context into the |
| 752 | * work queue. |
| 753 | */ |
| 754 | aio_queue_work(ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 755 | } |
| 756 | } |
| 757 | return ret; |
| 758 | } |
| 759 | |
| 760 | /* |
| 761 | * __aio_run_iocbs: |
| 762 | * Process all pending retries queued on the ioctx |
| 763 | * run list. |
| 764 | * Assumes it is operating within the aio issuer's mm |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 765 | * context. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | */ |
| 767 | static int __aio_run_iocbs(struct kioctx *ctx) |
| 768 | { |
| 769 | struct kiocb *iocb; |
Oleg Nesterov | 626ab0e | 2006-06-23 02:05:55 -0700 | [diff] [blame] | 770 | struct list_head run_list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 772 | assert_spin_locked(&ctx->ctx_lock); |
| 773 | |
Oleg Nesterov | 626ab0e | 2006-06-23 02:05:55 -0700 | [diff] [blame] | 774 | list_replace_init(&ctx->run_list, &run_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 775 | while (!list_empty(&run_list)) { |
| 776 | iocb = list_entry(run_list.next, struct kiocb, |
| 777 | ki_run_list); |
| 778 | list_del(&iocb->ki_run_list); |
| 779 | /* |
| 780 | * Hold an extra reference while retrying i/o. |
| 781 | */ |
| 782 | iocb->ki_users++; /* grab extra reference */ |
| 783 | aio_run_iocb(iocb); |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 784 | __aio_put_req(ctx, iocb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | if (!list_empty(&ctx->run_list)) |
| 787 | return 1; |
| 788 | return 0; |
| 789 | } |
| 790 | |
| 791 | static void aio_queue_work(struct kioctx * ctx) |
| 792 | { |
| 793 | unsigned long timeout; |
| 794 | /* |
| 795 | * if someone is waiting, get the work started right |
| 796 | * away, otherwise, use a longer delay |
| 797 | */ |
| 798 | smp_mb(); |
| 799 | if (waitqueue_active(&ctx->wait)) |
| 800 | timeout = 1; |
| 801 | else |
| 802 | timeout = HZ/10; |
| 803 | queue_delayed_work(aio_wq, &ctx->wq, timeout); |
| 804 | } |
| 805 | |
| 806 | |
| 807 | /* |
| 808 | * aio_run_iocbs: |
| 809 | * Process all pending retries queued on the ioctx |
| 810 | * run list. |
| 811 | * Assumes it is operating within the aio issuer's mm |
| 812 | * context. |
| 813 | */ |
| 814 | static inline void aio_run_iocbs(struct kioctx *ctx) |
| 815 | { |
| 816 | int requeue; |
| 817 | |
| 818 | spin_lock_irq(&ctx->ctx_lock); |
| 819 | |
| 820 | requeue = __aio_run_iocbs(ctx); |
| 821 | spin_unlock_irq(&ctx->ctx_lock); |
| 822 | if (requeue) |
| 823 | aio_queue_work(ctx); |
| 824 | } |
| 825 | |
| 826 | /* |
| 827 | * just like aio_run_iocbs, but keeps running them until |
| 828 | * the list stays empty |
| 829 | */ |
| 830 | static inline void aio_run_all_iocbs(struct kioctx *ctx) |
| 831 | { |
| 832 | spin_lock_irq(&ctx->ctx_lock); |
| 833 | while (__aio_run_iocbs(ctx)) |
| 834 | ; |
| 835 | spin_unlock_irq(&ctx->ctx_lock); |
| 836 | } |
| 837 | |
| 838 | /* |
| 839 | * aio_kick_handler: |
| 840 | * Work queue handler triggered to process pending |
| 841 | * retries on an ioctx. Takes on the aio issuer's |
| 842 | * mm context before running the iocbs, so that |
| 843 | * copy_xxx_user operates on the issuer's address |
| 844 | * space. |
| 845 | * Run on aiod's context. |
| 846 | */ |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 847 | static void aio_kick_handler(struct work_struct *work) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 848 | { |
David Howells | 65f27f3 | 2006-11-22 14:55:48 +0000 | [diff] [blame] | 849 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | mm_segment_t oldfs = get_fs(); |
Zach Brown | 1ebb110 | 2006-12-29 16:47:02 -0800 | [diff] [blame] | 851 | struct mm_struct *mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 852 | int requeue; |
| 853 | |
| 854 | set_fs(USER_DS); |
| 855 | use_mm(ctx->mm); |
| 856 | spin_lock_irq(&ctx->ctx_lock); |
| 857 | requeue =__aio_run_iocbs(ctx); |
Zach Brown | 1ebb110 | 2006-12-29 16:47:02 -0800 | [diff] [blame] | 858 | mm = ctx->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | spin_unlock_irq(&ctx->ctx_lock); |
Zach Brown | 1ebb110 | 2006-12-29 16:47:02 -0800 | [diff] [blame] | 860 | unuse_mm(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | set_fs(oldfs); |
| 862 | /* |
| 863 | * we're in a worker thread already, don't use queue_delayed_work, |
| 864 | */ |
| 865 | if (requeue) |
David Howells | 52bad64 | 2006-11-22 14:54:01 +0000 | [diff] [blame] | 866 | queue_delayed_work(aio_wq, &ctx->wq, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | } |
| 868 | |
| 869 | |
| 870 | /* |
| 871 | * Called by kick_iocb to queue the kiocb for retry |
| 872 | * and if required activate the aio work queue to process |
| 873 | * it |
| 874 | */ |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 875 | static void try_queue_kicked_iocb(struct kiocb *iocb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 876 | { |
| 877 | struct kioctx *ctx = iocb->ki_ctx; |
| 878 | unsigned long flags; |
| 879 | int run = 0; |
| 880 | |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 881 | /* We're supposed to be the only path putting the iocb back on the run |
| 882 | * list. If we find that the iocb is *back* on a wait queue already |
| 883 | * than retry has happened before we could queue the iocb. This also |
| 884 | * means that the retry could have completed and freed our iocb, no |
| 885 | * good. */ |
| 886 | BUG_ON((!list_empty(&iocb->ki_wait.task_list))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | |
| 888 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 889 | /* set this inside the lock so that we can't race with aio_run_iocb() |
| 890 | * testing it and putting the iocb on the run list under the lock */ |
| 891 | if (!kiocbTryKick(iocb)) |
| 892 | run = __queue_kicked_iocb(iocb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
Ken Chen | 644d3a0 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 894 | if (run) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 895 | aio_queue_work(ctx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 896 | } |
| 897 | |
| 898 | /* |
| 899 | * kick_iocb: |
| 900 | * Called typically from a wait queue callback context |
| 901 | * (aio_wake_function) to trigger a retry of the iocb. |
| 902 | * The retry is usually executed by aio workqueue |
| 903 | * threads (See aio_kick_handler). |
| 904 | */ |
| 905 | void fastcall kick_iocb(struct kiocb *iocb) |
| 906 | { |
| 907 | /* sync iocbs are easy: they can only ever be executing from a |
| 908 | * single context. */ |
| 909 | if (is_sync_kiocb(iocb)) { |
| 910 | kiocbSetKicked(iocb); |
| 911 | wake_up_process(iocb->ki_obj.tsk); |
| 912 | return; |
| 913 | } |
| 914 | |
Zach Brown | 998765e | 2005-09-30 11:58:54 -0700 | [diff] [blame] | 915 | try_queue_kicked_iocb(iocb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | } |
| 917 | EXPORT_SYMBOL(kick_iocb); |
| 918 | |
| 919 | /* aio_complete |
| 920 | * Called when the io request on the given iocb is complete. |
| 921 | * Returns true if this is the last user of the request. The |
| 922 | * only other user of the request can be the cancellation code. |
| 923 | */ |
| 924 | int fastcall aio_complete(struct kiocb *iocb, long res, long res2) |
| 925 | { |
| 926 | struct kioctx *ctx = iocb->ki_ctx; |
| 927 | struct aio_ring_info *info; |
| 928 | struct aio_ring *ring; |
| 929 | struct io_event *event; |
| 930 | unsigned long flags; |
| 931 | unsigned long tail; |
| 932 | int ret; |
| 933 | |
Zach Brown | 20dcae3 | 2005-11-13 16:07:33 -0800 | [diff] [blame] | 934 | /* |
| 935 | * Special case handling for sync iocbs: |
| 936 | * - events go directly into the iocb for fast handling |
| 937 | * - the sync task with the iocb in its stack holds the single iocb |
| 938 | * ref, no other paths have a way to get another ref |
| 939 | * - the sync task helpfully left a reference to itself in the iocb |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | */ |
| 941 | if (is_sync_kiocb(iocb)) { |
Zach Brown | 20dcae3 | 2005-11-13 16:07:33 -0800 | [diff] [blame] | 942 | BUG_ON(iocb->ki_users != 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 943 | iocb->ki_user_data = res; |
Zach Brown | 20dcae3 | 2005-11-13 16:07:33 -0800 | [diff] [blame] | 944 | iocb->ki_users = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 945 | wake_up_process(iocb->ki_obj.tsk); |
Zach Brown | 20dcae3 | 2005-11-13 16:07:33 -0800 | [diff] [blame] | 946 | return 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | } |
| 948 | |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 949 | /* |
| 950 | * Check if the user asked us to deliver the result through an |
| 951 | * eventfd. The eventfd_signal() function is safe to be called |
| 952 | * from IRQ context. |
| 953 | */ |
| 954 | if (!IS_ERR(iocb->ki_eventfd)) |
| 955 | eventfd_signal(iocb->ki_eventfd, 1); |
| 956 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | info = &ctx->ring_info; |
| 958 | |
| 959 | /* add a completion event to the ring buffer. |
| 960 | * must be done holding ctx->ctx_lock to prevent |
| 961 | * other code from messing with the tail |
| 962 | * pointer since we might be called from irq |
| 963 | * context. |
| 964 | */ |
| 965 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
| 966 | |
| 967 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
| 968 | list_del_init(&iocb->ki_run_list); |
| 969 | |
| 970 | /* |
| 971 | * cancelled requests don't get events, userland was given one |
| 972 | * when the event got cancelled. |
| 973 | */ |
| 974 | if (kiocbIsCancelled(iocb)) |
| 975 | goto put_rq; |
| 976 | |
| 977 | ring = kmap_atomic(info->ring_pages[0], KM_IRQ1); |
| 978 | |
| 979 | tail = info->tail; |
| 980 | event = aio_ring_event(info, tail, KM_IRQ0); |
Ken Chen | 4bf69b2 | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 981 | if (++tail >= info->nr) |
| 982 | tail = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | |
| 984 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
| 985 | event->data = iocb->ki_user_data; |
| 986 | event->res = res; |
| 987 | event->res2 = res2; |
| 988 | |
| 989 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
| 990 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
| 991 | res, res2); |
| 992 | |
| 993 | /* after flagging the request as done, we |
| 994 | * must never even look at it again |
| 995 | */ |
| 996 | smp_wmb(); /* make event visible before updating tail */ |
| 997 | |
| 998 | info->tail = tail; |
| 999 | ring->tail = tail; |
| 1000 | |
| 1001 | put_aio_ring_event(event, KM_IRQ0); |
| 1002 | kunmap_atomic(ring, KM_IRQ1); |
| 1003 | |
| 1004 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1005 | put_rq: |
| 1006 | /* everything turned out well, dispose of the aiocb. */ |
| 1007 | ret = __aio_put_req(ctx, iocb); |
| 1008 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1009 | if (waitqueue_active(&ctx->wait)) |
| 1010 | wake_up(&ctx->wait); |
| 1011 | |
Ken Chen | dee11c2 | 2007-02-03 01:13:45 -0800 | [diff] [blame] | 1012 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | return ret; |
| 1014 | } |
| 1015 | |
| 1016 | /* aio_read_evt |
| 1017 | * Pull an event off of the ioctx's event ring. Returns the number of |
| 1018 | * events fetched (0 or 1 ;-) |
| 1019 | * FIXME: make this use cmpxchg. |
| 1020 | * TODO: make the ringbuffer user mmap()able (requires FIXME). |
| 1021 | */ |
| 1022 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
| 1023 | { |
| 1024 | struct aio_ring_info *info = &ioctx->ring_info; |
| 1025 | struct aio_ring *ring; |
| 1026 | unsigned long head; |
| 1027 | int ret = 0; |
| 1028 | |
| 1029 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
| 1030 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
| 1031 | (unsigned long)ring->head, (unsigned long)ring->tail, |
| 1032 | (unsigned long)ring->nr); |
| 1033 | |
| 1034 | if (ring->head == ring->tail) |
| 1035 | goto out; |
| 1036 | |
| 1037 | spin_lock(&info->ring_lock); |
| 1038 | |
| 1039 | head = ring->head % info->nr; |
| 1040 | if (head != ring->tail) { |
| 1041 | struct io_event *evp = aio_ring_event(info, head, KM_USER1); |
| 1042 | *ent = *evp; |
| 1043 | head = (head + 1) % info->nr; |
| 1044 | smp_mb(); /* finish reading the event before updatng the head */ |
| 1045 | ring->head = head; |
| 1046 | ret = 1; |
| 1047 | put_aio_ring_event(evp, KM_USER1); |
| 1048 | } |
| 1049 | spin_unlock(&info->ring_lock); |
| 1050 | |
| 1051 | out: |
| 1052 | kunmap_atomic(ring, KM_USER0); |
| 1053 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
| 1054 | (unsigned long)ring->head, (unsigned long)ring->tail); |
| 1055 | return ret; |
| 1056 | } |
| 1057 | |
| 1058 | struct aio_timeout { |
| 1059 | struct timer_list timer; |
| 1060 | int timed_out; |
| 1061 | struct task_struct *p; |
| 1062 | }; |
| 1063 | |
| 1064 | static void timeout_func(unsigned long data) |
| 1065 | { |
| 1066 | struct aio_timeout *to = (struct aio_timeout *)data; |
| 1067 | |
| 1068 | to->timed_out = 1; |
| 1069 | wake_up_process(to->p); |
| 1070 | } |
| 1071 | |
| 1072 | static inline void init_timeout(struct aio_timeout *to) |
| 1073 | { |
| 1074 | init_timer(&to->timer); |
| 1075 | to->timer.data = (unsigned long)to; |
| 1076 | to->timer.function = timeout_func; |
| 1077 | to->timed_out = 0; |
| 1078 | to->p = current; |
| 1079 | } |
| 1080 | |
| 1081 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
| 1082 | const struct timespec *ts) |
| 1083 | { |
| 1084 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
| 1085 | if (time_after(to->timer.expires, jiffies)) |
| 1086 | add_timer(&to->timer); |
| 1087 | else |
| 1088 | to->timed_out = 1; |
| 1089 | } |
| 1090 | |
| 1091 | static inline void clear_timeout(struct aio_timeout *to) |
| 1092 | { |
| 1093 | del_singleshot_timer_sync(&to->timer); |
| 1094 | } |
| 1095 | |
| 1096 | static int read_events(struct kioctx *ctx, |
| 1097 | long min_nr, long nr, |
| 1098 | struct io_event __user *event, |
| 1099 | struct timespec __user *timeout) |
| 1100 | { |
| 1101 | long start_jiffies = jiffies; |
| 1102 | struct task_struct *tsk = current; |
| 1103 | DECLARE_WAITQUEUE(wait, tsk); |
| 1104 | int ret; |
| 1105 | int i = 0; |
| 1106 | struct io_event ent; |
| 1107 | struct aio_timeout to; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | int retry = 0; |
| 1109 | |
| 1110 | /* needed to zero any padding within an entry (there shouldn't be |
| 1111 | * any, but C is fun! |
| 1112 | */ |
| 1113 | memset(&ent, 0, sizeof(ent)); |
| 1114 | retry: |
| 1115 | ret = 0; |
| 1116 | while (likely(i < nr)) { |
| 1117 | ret = aio_read_evt(ctx, &ent); |
| 1118 | if (unlikely(ret <= 0)) |
| 1119 | break; |
| 1120 | |
| 1121 | dprintk("read event: %Lx %Lx %Lx %Lx\n", |
| 1122 | ent.data, ent.obj, ent.res, ent.res2); |
| 1123 | |
| 1124 | /* Could we split the check in two? */ |
| 1125 | ret = -EFAULT; |
| 1126 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| 1127 | dprintk("aio: lost an event due to EFAULT.\n"); |
| 1128 | break; |
| 1129 | } |
| 1130 | ret = 0; |
| 1131 | |
| 1132 | /* Good, event copied to userland, update counts. */ |
| 1133 | event ++; |
| 1134 | i ++; |
| 1135 | } |
| 1136 | |
| 1137 | if (min_nr <= i) |
| 1138 | return i; |
| 1139 | if (ret) |
| 1140 | return ret; |
| 1141 | |
| 1142 | /* End fast path */ |
| 1143 | |
| 1144 | /* racey check, but it gets redone */ |
| 1145 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
| 1146 | retry = 1; |
| 1147 | aio_run_all_iocbs(ctx); |
| 1148 | goto retry; |
| 1149 | } |
| 1150 | |
| 1151 | init_timeout(&to); |
| 1152 | if (timeout) { |
| 1153 | struct timespec ts; |
| 1154 | ret = -EFAULT; |
| 1155 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
| 1156 | goto out; |
| 1157 | |
| 1158 | set_timeout(start_jiffies, &to, &ts); |
| 1159 | } |
| 1160 | |
| 1161 | while (likely(i < nr)) { |
| 1162 | add_wait_queue_exclusive(&ctx->wait, &wait); |
| 1163 | do { |
| 1164 | set_task_state(tsk, TASK_INTERRUPTIBLE); |
| 1165 | ret = aio_read_evt(ctx, &ent); |
| 1166 | if (ret) |
| 1167 | break; |
| 1168 | if (min_nr <= i) |
| 1169 | break; |
| 1170 | ret = 0; |
| 1171 | if (to.timed_out) /* Only check after read evt */ |
| 1172 | break; |
| 1173 | schedule(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1174 | if (signal_pending(tsk)) { |
| 1175 | ret = -EINTR; |
| 1176 | break; |
| 1177 | } |
| 1178 | /*ret = aio_read_evt(ctx, &ent);*/ |
| 1179 | } while (1) ; |
| 1180 | |
| 1181 | set_task_state(tsk, TASK_RUNNING); |
| 1182 | remove_wait_queue(&ctx->wait, &wait); |
| 1183 | |
| 1184 | if (unlikely(ret <= 0)) |
| 1185 | break; |
| 1186 | |
| 1187 | ret = -EFAULT; |
| 1188 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
| 1189 | dprintk("aio: lost an event due to EFAULT.\n"); |
| 1190 | break; |
| 1191 | } |
| 1192 | |
| 1193 | /* Good, event copied to userland, update counts. */ |
| 1194 | event ++; |
| 1195 | i ++; |
| 1196 | } |
| 1197 | |
| 1198 | if (timeout) |
| 1199 | clear_timeout(&to); |
| 1200 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1201 | return i ? i : ret; |
| 1202 | } |
| 1203 | |
| 1204 | /* Take an ioctx and remove it from the list of ioctx's. Protects |
| 1205 | * against races with itself via ->dead. |
| 1206 | */ |
| 1207 | static void io_destroy(struct kioctx *ioctx) |
| 1208 | { |
| 1209 | struct mm_struct *mm = current->mm; |
| 1210 | struct kioctx **tmp; |
| 1211 | int was_dead; |
| 1212 | |
| 1213 | /* delete the entry from the list is someone else hasn't already */ |
| 1214 | write_lock(&mm->ioctx_list_lock); |
| 1215 | was_dead = ioctx->dead; |
| 1216 | ioctx->dead = 1; |
| 1217 | for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx; |
| 1218 | tmp = &(*tmp)->next) |
| 1219 | ; |
| 1220 | if (*tmp) |
| 1221 | *tmp = ioctx->next; |
| 1222 | write_unlock(&mm->ioctx_list_lock); |
| 1223 | |
| 1224 | dprintk("aio_release(%p)\n", ioctx); |
| 1225 | if (likely(!was_dead)) |
| 1226 | put_ioctx(ioctx); /* twice for the list */ |
| 1227 | |
| 1228 | aio_cancel_all(ioctx); |
| 1229 | wait_for_all_aios(ioctx); |
| 1230 | put_ioctx(ioctx); /* once for the lookup */ |
| 1231 | } |
| 1232 | |
| 1233 | /* sys_io_setup: |
| 1234 | * Create an aio_context capable of receiving at least nr_events. |
| 1235 | * ctxp must not point to an aio_context that already exists, and |
| 1236 | * must be initialized to 0 prior to the call. On successful |
| 1237 | * creation of the aio_context, *ctxp is filled in with the resulting |
| 1238 | * handle. May fail with -EINVAL if *ctxp is not initialized, |
| 1239 | * if the specified nr_events exceeds internal limits. May fail |
| 1240 | * with -EAGAIN if the specified nr_events exceeds the user's limit |
| 1241 | * of available events. May fail with -ENOMEM if insufficient kernel |
| 1242 | * resources are available. May fail with -EFAULT if an invalid |
| 1243 | * pointer is passed for ctxp. Will fail with -ENOSYS if not |
| 1244 | * implemented. |
| 1245 | */ |
| 1246 | asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t __user *ctxp) |
| 1247 | { |
| 1248 | struct kioctx *ioctx = NULL; |
| 1249 | unsigned long ctx; |
| 1250 | long ret; |
| 1251 | |
| 1252 | ret = get_user(ctx, ctxp); |
| 1253 | if (unlikely(ret)) |
| 1254 | goto out; |
| 1255 | |
| 1256 | ret = -EINVAL; |
Zach Brown | d55b5fd | 2005-11-07 00:59:31 -0800 | [diff] [blame] | 1257 | if (unlikely(ctx || nr_events == 0)) { |
| 1258 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", |
| 1259 | ctx, nr_events); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1260 | goto out; |
| 1261 | } |
| 1262 | |
| 1263 | ioctx = ioctx_alloc(nr_events); |
| 1264 | ret = PTR_ERR(ioctx); |
| 1265 | if (!IS_ERR(ioctx)) { |
| 1266 | ret = put_user(ioctx->user_id, ctxp); |
| 1267 | if (!ret) |
| 1268 | return 0; |
| 1269 | |
| 1270 | get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ |
| 1271 | io_destroy(ioctx); |
| 1272 | } |
| 1273 | |
| 1274 | out: |
| 1275 | return ret; |
| 1276 | } |
| 1277 | |
| 1278 | /* sys_io_destroy: |
| 1279 | * Destroy the aio_context specified. May cancel any outstanding |
| 1280 | * AIOs and block on completion. Will fail with -ENOSYS if not |
| 1281 | * implemented. May fail with -EFAULT if the context pointed to |
| 1282 | * is invalid. |
| 1283 | */ |
| 1284 | asmlinkage long sys_io_destroy(aio_context_t ctx) |
| 1285 | { |
| 1286 | struct kioctx *ioctx = lookup_ioctx(ctx); |
| 1287 | if (likely(NULL != ioctx)) { |
| 1288 | io_destroy(ioctx); |
| 1289 | return 0; |
| 1290 | } |
| 1291 | pr_debug("EINVAL: io_destroy: invalid context id\n"); |
| 1292 | return -EINVAL; |
| 1293 | } |
| 1294 | |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1295 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) |
| 1296 | { |
| 1297 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; |
| 1298 | |
| 1299 | BUG_ON(ret <= 0); |
| 1300 | |
| 1301 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { |
| 1302 | ssize_t this = min((ssize_t)iov->iov_len, ret); |
| 1303 | iov->iov_base += this; |
| 1304 | iov->iov_len -= this; |
| 1305 | iocb->ki_left -= this; |
| 1306 | ret -= this; |
| 1307 | if (iov->iov_len == 0) { |
| 1308 | iocb->ki_cur_seg++; |
| 1309 | iov++; |
| 1310 | } |
| 1311 | } |
| 1312 | |
| 1313 | /* the caller should not have done more io than what fit in |
| 1314 | * the remaining iovecs */ |
| 1315 | BUG_ON(ret > 0 && iocb->ki_left == 0); |
| 1316 | } |
| 1317 | |
| 1318 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1319 | { |
| 1320 | struct file *file = iocb->ki_filp; |
| 1321 | struct address_space *mapping = file->f_mapping; |
| 1322 | struct inode *inode = mapping->host; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1323 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, |
| 1324 | unsigned long, loff_t); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1325 | ssize_t ret = 0; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1326 | unsigned short opcode; |
| 1327 | |
| 1328 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || |
| 1329 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { |
| 1330 | rw_op = file->f_op->aio_read; |
| 1331 | opcode = IOCB_CMD_PREADV; |
| 1332 | } else { |
| 1333 | rw_op = file->f_op->aio_write; |
| 1334 | opcode = IOCB_CMD_PWRITEV; |
| 1335 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1336 | |
Zach Brown | 897f15f | 2005-09-30 11:58:55 -0700 | [diff] [blame] | 1337 | do { |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1338 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], |
| 1339 | iocb->ki_nr_segs - iocb->ki_cur_seg, |
| 1340 | iocb->ki_pos); |
| 1341 | if (ret > 0) |
| 1342 | aio_advance_iovec(iocb, ret); |
Badari Pulavarty | 027445c | 2006-09-30 23:28:46 -0700 | [diff] [blame] | 1343 | |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1344 | /* retry all partial writes. retry partial reads as long as its a |
| 1345 | * regular file. */ |
Zach Brown | 353fb07 | 2005-09-30 11:58:56 -0700 | [diff] [blame] | 1346 | } while (ret > 0 && iocb->ki_left > 0 && |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1347 | (opcode == IOCB_CMD_PWRITEV || |
| 1348 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1349 | |
| 1350 | /* This means we must have transferred all that we could */ |
| 1351 | /* No need to retry anymore */ |
| 1352 | if ((ret == 0) || (iocb->ki_left == 0)) |
| 1353 | ret = iocb->ki_nbytes - iocb->ki_left; |
| 1354 | |
| 1355 | return ret; |
| 1356 | } |
| 1357 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1358 | static ssize_t aio_fdsync(struct kiocb *iocb) |
| 1359 | { |
| 1360 | struct file *file = iocb->ki_filp; |
| 1361 | ssize_t ret = -EINVAL; |
| 1362 | |
| 1363 | if (file->f_op->aio_fsync) |
| 1364 | ret = file->f_op->aio_fsync(iocb, 1); |
| 1365 | return ret; |
| 1366 | } |
| 1367 | |
| 1368 | static ssize_t aio_fsync(struct kiocb *iocb) |
| 1369 | { |
| 1370 | struct file *file = iocb->ki_filp; |
| 1371 | ssize_t ret = -EINVAL; |
| 1372 | |
| 1373 | if (file->f_op->aio_fsync) |
| 1374 | ret = file->f_op->aio_fsync(iocb, 0); |
| 1375 | return ret; |
| 1376 | } |
| 1377 | |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1378 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb) |
| 1379 | { |
| 1380 | ssize_t ret; |
| 1381 | |
| 1382 | ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf, |
| 1383 | kiocb->ki_nbytes, 1, |
| 1384 | &kiocb->ki_inline_vec, &kiocb->ki_iovec); |
| 1385 | if (ret < 0) |
| 1386 | goto out; |
| 1387 | |
| 1388 | kiocb->ki_nr_segs = kiocb->ki_nbytes; |
| 1389 | kiocb->ki_cur_seg = 0; |
| 1390 | /* ki_nbytes/left now reflect bytes instead of segs */ |
| 1391 | kiocb->ki_nbytes = ret; |
| 1392 | kiocb->ki_left = ret; |
| 1393 | |
| 1394 | ret = 0; |
| 1395 | out: |
| 1396 | return ret; |
| 1397 | } |
| 1398 | |
| 1399 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb) |
| 1400 | { |
| 1401 | kiocb->ki_iovec = &kiocb->ki_inline_vec; |
| 1402 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; |
| 1403 | kiocb->ki_iovec->iov_len = kiocb->ki_left; |
| 1404 | kiocb->ki_nr_segs = 1; |
| 1405 | kiocb->ki_cur_seg = 0; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1406 | return 0; |
| 1407 | } |
| 1408 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1409 | /* |
| 1410 | * aio_setup_iocb: |
| 1411 | * Performs the initial checks and aio retry method |
| 1412 | * setup for the kiocb at the time of io submission. |
| 1413 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1414 | static ssize_t aio_setup_iocb(struct kiocb *kiocb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | { |
| 1416 | struct file *file = kiocb->ki_filp; |
| 1417 | ssize_t ret = 0; |
| 1418 | |
| 1419 | switch (kiocb->ki_opcode) { |
| 1420 | case IOCB_CMD_PREAD: |
| 1421 | ret = -EBADF; |
| 1422 | if (unlikely(!(file->f_mode & FMODE_READ))) |
| 1423 | break; |
| 1424 | ret = -EFAULT; |
| 1425 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
| 1426 | kiocb->ki_left))) |
| 1427 | break; |
Kostik Belousov | 8766ce4 | 2005-10-23 12:57:13 -0700 | [diff] [blame] | 1428 | ret = security_file_permission(file, MAY_READ); |
| 1429 | if (unlikely(ret)) |
| 1430 | break; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1431 | ret = aio_setup_single_vector(kiocb); |
| 1432 | if (ret) |
| 1433 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1434 | ret = -EINVAL; |
| 1435 | if (file->f_op->aio_read) |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1436 | kiocb->ki_retry = aio_rw_vect_retry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | break; |
| 1438 | case IOCB_CMD_PWRITE: |
| 1439 | ret = -EBADF; |
| 1440 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| 1441 | break; |
| 1442 | ret = -EFAULT; |
| 1443 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
| 1444 | kiocb->ki_left))) |
| 1445 | break; |
Kostik Belousov | 8766ce4 | 2005-10-23 12:57:13 -0700 | [diff] [blame] | 1446 | ret = security_file_permission(file, MAY_WRITE); |
| 1447 | if (unlikely(ret)) |
| 1448 | break; |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1449 | ret = aio_setup_single_vector(kiocb); |
| 1450 | if (ret) |
| 1451 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | ret = -EINVAL; |
| 1453 | if (file->f_op->aio_write) |
Badari Pulavarty | eed4e51 | 2006-09-30 23:28:49 -0700 | [diff] [blame] | 1454 | kiocb->ki_retry = aio_rw_vect_retry; |
| 1455 | break; |
| 1456 | case IOCB_CMD_PREADV: |
| 1457 | ret = -EBADF; |
| 1458 | if (unlikely(!(file->f_mode & FMODE_READ))) |
| 1459 | break; |
| 1460 | ret = security_file_permission(file, MAY_READ); |
| 1461 | if (unlikely(ret)) |
| 1462 | break; |
| 1463 | ret = aio_setup_vectored_rw(READ, kiocb); |
| 1464 | if (ret) |
| 1465 | break; |
| 1466 | ret = -EINVAL; |
| 1467 | if (file->f_op->aio_read) |
| 1468 | kiocb->ki_retry = aio_rw_vect_retry; |
| 1469 | break; |
| 1470 | case IOCB_CMD_PWRITEV: |
| 1471 | ret = -EBADF; |
| 1472 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| 1473 | break; |
| 1474 | ret = security_file_permission(file, MAY_WRITE); |
| 1475 | if (unlikely(ret)) |
| 1476 | break; |
| 1477 | ret = aio_setup_vectored_rw(WRITE, kiocb); |
| 1478 | if (ret) |
| 1479 | break; |
| 1480 | ret = -EINVAL; |
| 1481 | if (file->f_op->aio_write) |
| 1482 | kiocb->ki_retry = aio_rw_vect_retry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | break; |
| 1484 | case IOCB_CMD_FDSYNC: |
| 1485 | ret = -EINVAL; |
| 1486 | if (file->f_op->aio_fsync) |
| 1487 | kiocb->ki_retry = aio_fdsync; |
| 1488 | break; |
| 1489 | case IOCB_CMD_FSYNC: |
| 1490 | ret = -EINVAL; |
| 1491 | if (file->f_op->aio_fsync) |
| 1492 | kiocb->ki_retry = aio_fsync; |
| 1493 | break; |
| 1494 | default: |
| 1495 | dprintk("EINVAL: io_submit: no operation provided\n"); |
| 1496 | ret = -EINVAL; |
| 1497 | } |
| 1498 | |
| 1499 | if (!kiocb->ki_retry) |
| 1500 | return ret; |
| 1501 | |
| 1502 | return 0; |
| 1503 | } |
| 1504 | |
| 1505 | /* |
| 1506 | * aio_wake_function: |
| 1507 | * wait queue callback function for aio notification, |
| 1508 | * Simply triggers a retry of the operation via kick_iocb. |
| 1509 | * |
| 1510 | * This callback is specified in the wait queue entry in |
| 1511 | * a kiocb (current->io_wait points to this wait queue |
| 1512 | * entry when an aio operation executes; it is used |
| 1513 | * instead of a synchronous wait when an i/o blocking |
| 1514 | * condition is encountered during aio). |
| 1515 | * |
| 1516 | * Note: |
| 1517 | * This routine is executed with the wait queue lock held. |
| 1518 | * Since kick_iocb acquires iocb->ctx->ctx_lock, it nests |
| 1519 | * the ioctx lock inside the wait queue lock. This is safe |
| 1520 | * because this callback isn't used for wait queues which |
| 1521 | * are nested inside ioctx lock (i.e. ctx->wait) |
| 1522 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1523 | static int aio_wake_function(wait_queue_t *wait, unsigned mode, |
| 1524 | int sync, void *key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1525 | { |
| 1526 | struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait); |
| 1527 | |
| 1528 | list_del_init(&wait->task_list); |
| 1529 | kick_iocb(iocb); |
| 1530 | return 1; |
| 1531 | } |
| 1532 | |
| 1533 | int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
| 1534 | struct iocb *iocb) |
| 1535 | { |
| 1536 | struct kiocb *req; |
| 1537 | struct file *file; |
| 1538 | ssize_t ret; |
| 1539 | |
| 1540 | /* enforce forwards compatibility on users */ |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 1541 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1542 | pr_debug("EINVAL: io_submit: reserve field set\n"); |
| 1543 | return -EINVAL; |
| 1544 | } |
| 1545 | |
| 1546 | /* prevent overflows */ |
| 1547 | if (unlikely( |
| 1548 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || |
| 1549 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || |
| 1550 | ((ssize_t)iocb->aio_nbytes < 0) |
| 1551 | )) { |
| 1552 | pr_debug("EINVAL: io_submit: overflow check\n"); |
| 1553 | return -EINVAL; |
| 1554 | } |
| 1555 | |
| 1556 | file = fget(iocb->aio_fildes); |
| 1557 | if (unlikely(!file)) |
| 1558 | return -EBADF; |
| 1559 | |
| 1560 | req = aio_get_req(ctx); /* returns with 2 references to req */ |
| 1561 | if (unlikely(!req)) { |
| 1562 | fput(file); |
| 1563 | return -EAGAIN; |
| 1564 | } |
Yan Zheng | 87e2831 | 2007-10-08 12:16:20 -0700 | [diff] [blame^] | 1565 | req->ki_filp = file; |
Davide Libenzi | 9c3060b | 2007-05-10 22:23:21 -0700 | [diff] [blame] | 1566 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
| 1567 | /* |
| 1568 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an |
| 1569 | * instance of the file* now. The file descriptor must be |
| 1570 | * an eventfd() fd, and will be signaled for each completed |
| 1571 | * event using the eventfd_signal() function. |
| 1572 | */ |
| 1573 | req->ki_eventfd = eventfd_fget((int) iocb->aio_resfd); |
| 1574 | if (unlikely(IS_ERR(req->ki_eventfd))) { |
| 1575 | ret = PTR_ERR(req->ki_eventfd); |
| 1576 | goto out_put_req; |
| 1577 | } |
| 1578 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1579 | |
Ken Chen | 212079c | 2005-05-01 08:59:15 -0700 | [diff] [blame] | 1580 | ret = put_user(req->ki_key, &user_iocb->aio_key); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1581 | if (unlikely(ret)) { |
| 1582 | dprintk("EFAULT: aio_key\n"); |
| 1583 | goto out_put_req; |
| 1584 | } |
| 1585 | |
| 1586 | req->ki_obj.user = user_iocb; |
| 1587 | req->ki_user_data = iocb->aio_data; |
| 1588 | req->ki_pos = iocb->aio_offset; |
| 1589 | |
| 1590 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
| 1591 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
| 1592 | req->ki_opcode = iocb->aio_lio_opcode; |
| 1593 | init_waitqueue_func_entry(&req->ki_wait, aio_wake_function); |
| 1594 | INIT_LIST_HEAD(&req->ki_wait.task_list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1595 | |
| 1596 | ret = aio_setup_iocb(req); |
| 1597 | |
| 1598 | if (ret) |
| 1599 | goto out_put_req; |
| 1600 | |
| 1601 | spin_lock_irq(&ctx->ctx_lock); |
Benjamin LaHaise | ac0b1bc | 2005-09-09 13:02:09 -0700 | [diff] [blame] | 1602 | aio_run_iocb(req); |
Benjamin LaHaise | ac0b1bc | 2005-09-09 13:02:09 -0700 | [diff] [blame] | 1603 | if (!list_empty(&ctx->run_list)) { |
Ken Chen | 954d3e9 | 2005-05-01 08:59:16 -0700 | [diff] [blame] | 1604 | /* drain the run list */ |
| 1605 | while (__aio_run_iocbs(ctx)) |
| 1606 | ; |
| 1607 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | spin_unlock_irq(&ctx->ctx_lock); |
| 1609 | aio_put_req(req); /* drop extra ref to req */ |
| 1610 | return 0; |
| 1611 | |
| 1612 | out_put_req: |
| 1613 | aio_put_req(req); /* drop extra ref to req */ |
| 1614 | aio_put_req(req); /* drop i/o ref to req */ |
| 1615 | return ret; |
| 1616 | } |
| 1617 | |
| 1618 | /* sys_io_submit: |
| 1619 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns |
| 1620 | * the number of iocbs queued. May return -EINVAL if the aio_context |
| 1621 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at |
| 1622 | * *iocbpp[0] is not properly initialized, if the operation specified |
| 1623 | * is invalid for the file descriptor in the iocb. May fail with |
| 1624 | * -EFAULT if any of the data structures point to invalid data. May |
| 1625 | * fail with -EBADF if the file descriptor specified in the first |
| 1626 | * iocb is invalid. May fail with -EAGAIN if insufficient resources |
| 1627 | * are available to queue any iocbs. Will return 0 if nr is 0. Will |
| 1628 | * fail with -ENOSYS if not implemented. |
| 1629 | */ |
| 1630 | asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr, |
| 1631 | struct iocb __user * __user *iocbpp) |
| 1632 | { |
| 1633 | struct kioctx *ctx; |
| 1634 | long ret = 0; |
| 1635 | int i; |
| 1636 | |
| 1637 | if (unlikely(nr < 0)) |
| 1638 | return -EINVAL; |
| 1639 | |
| 1640 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
| 1641 | return -EFAULT; |
| 1642 | |
| 1643 | ctx = lookup_ioctx(ctx_id); |
| 1644 | if (unlikely(!ctx)) { |
| 1645 | pr_debug("EINVAL: io_submit: invalid context id\n"); |
| 1646 | return -EINVAL; |
| 1647 | } |
| 1648 | |
| 1649 | /* |
| 1650 | * AKPM: should this return a partial result if some of the IOs were |
| 1651 | * successfully submitted? |
| 1652 | */ |
| 1653 | for (i=0; i<nr; i++) { |
| 1654 | struct iocb __user *user_iocb; |
| 1655 | struct iocb tmp; |
| 1656 | |
| 1657 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
| 1658 | ret = -EFAULT; |
| 1659 | break; |
| 1660 | } |
| 1661 | |
| 1662 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
| 1663 | ret = -EFAULT; |
| 1664 | break; |
| 1665 | } |
| 1666 | |
| 1667 | ret = io_submit_one(ctx, user_iocb, &tmp); |
| 1668 | if (ret) |
| 1669 | break; |
| 1670 | } |
| 1671 | |
| 1672 | put_ioctx(ctx); |
| 1673 | return i ? i : ret; |
| 1674 | } |
| 1675 | |
| 1676 | /* lookup_kiocb |
| 1677 | * Finds a given iocb for cancellation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1678 | */ |
Adrian Bunk | 25ee7e3 | 2005-04-25 08:18:14 -0700 | [diff] [blame] | 1679 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
| 1680 | u32 key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1681 | { |
| 1682 | struct list_head *pos; |
Zach Brown | d00689a | 2005-11-13 16:07:34 -0800 | [diff] [blame] | 1683 | |
| 1684 | assert_spin_locked(&ctx->ctx_lock); |
| 1685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | /* TODO: use a hash or array, this sucks. */ |
| 1687 | list_for_each(pos, &ctx->active_reqs) { |
| 1688 | struct kiocb *kiocb = list_kiocb(pos); |
| 1689 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
| 1690 | return kiocb; |
| 1691 | } |
| 1692 | return NULL; |
| 1693 | } |
| 1694 | |
| 1695 | /* sys_io_cancel: |
| 1696 | * Attempts to cancel an iocb previously passed to io_submit. If |
| 1697 | * the operation is successfully cancelled, the resulting event is |
| 1698 | * copied into the memory pointed to by result without being placed |
| 1699 | * into the completion queue and 0 is returned. May fail with |
| 1700 | * -EFAULT if any of the data structures pointed to are invalid. |
| 1701 | * May fail with -EINVAL if aio_context specified by ctx_id is |
| 1702 | * invalid. May fail with -EAGAIN if the iocb specified was not |
| 1703 | * cancelled. Will fail with -ENOSYS if not implemented. |
| 1704 | */ |
| 1705 | asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb, |
| 1706 | struct io_event __user *result) |
| 1707 | { |
| 1708 | int (*cancel)(struct kiocb *iocb, struct io_event *res); |
| 1709 | struct kioctx *ctx; |
| 1710 | struct kiocb *kiocb; |
| 1711 | u32 key; |
| 1712 | int ret; |
| 1713 | |
| 1714 | ret = get_user(key, &iocb->aio_key); |
| 1715 | if (unlikely(ret)) |
| 1716 | return -EFAULT; |
| 1717 | |
| 1718 | ctx = lookup_ioctx(ctx_id); |
| 1719 | if (unlikely(!ctx)) |
| 1720 | return -EINVAL; |
| 1721 | |
| 1722 | spin_lock_irq(&ctx->ctx_lock); |
| 1723 | ret = -EAGAIN; |
| 1724 | kiocb = lookup_kiocb(ctx, iocb, key); |
| 1725 | if (kiocb && kiocb->ki_cancel) { |
| 1726 | cancel = kiocb->ki_cancel; |
| 1727 | kiocb->ki_users ++; |
| 1728 | kiocbSetCancelled(kiocb); |
| 1729 | } else |
| 1730 | cancel = NULL; |
| 1731 | spin_unlock_irq(&ctx->ctx_lock); |
| 1732 | |
| 1733 | if (NULL != cancel) { |
| 1734 | struct io_event tmp; |
| 1735 | pr_debug("calling cancel\n"); |
| 1736 | memset(&tmp, 0, sizeof(tmp)); |
| 1737 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
| 1738 | tmp.data = kiocb->ki_user_data; |
| 1739 | ret = cancel(kiocb, &tmp); |
| 1740 | if (!ret) { |
| 1741 | /* Cancellation succeeded -- copy the result |
| 1742 | * into the user's buffer. |
| 1743 | */ |
| 1744 | if (copy_to_user(result, &tmp, sizeof(tmp))) |
| 1745 | ret = -EFAULT; |
| 1746 | } |
| 1747 | } else |
Wendy Cheng | 8f58202 | 2005-09-09 13:02:08 -0700 | [diff] [blame] | 1748 | ret = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1749 | |
| 1750 | put_ioctx(ctx); |
| 1751 | |
| 1752 | return ret; |
| 1753 | } |
| 1754 | |
| 1755 | /* io_getevents: |
| 1756 | * Attempts to read at least min_nr events and up to nr events from |
| 1757 | * the completion queue for the aio_context specified by ctx_id. May |
| 1758 | * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range, |
| 1759 | * if nr is out of range, if when is out of range. May fail with |
| 1760 | * -EFAULT if any of the memory specified to is invalid. May return |
| 1761 | * 0 or < min_nr if no events are available and the timeout specified |
| 1762 | * by when has elapsed, where when == NULL specifies an infinite |
| 1763 | * timeout. Note that the timeout pointed to by when is relative and |
| 1764 | * will be updated if not NULL and the operation blocks. Will fail |
| 1765 | * with -ENOSYS if not implemented. |
| 1766 | */ |
| 1767 | asmlinkage long sys_io_getevents(aio_context_t ctx_id, |
| 1768 | long min_nr, |
| 1769 | long nr, |
| 1770 | struct io_event __user *events, |
| 1771 | struct timespec __user *timeout) |
| 1772 | { |
| 1773 | struct kioctx *ioctx = lookup_ioctx(ctx_id); |
| 1774 | long ret = -EINVAL; |
| 1775 | |
| 1776 | if (likely(ioctx)) { |
| 1777 | if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0)) |
| 1778 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
| 1779 | put_ioctx(ioctx); |
| 1780 | } |
| 1781 | |
| 1782 | return ret; |
| 1783 | } |
| 1784 | |
| 1785 | __initcall(aio_setup); |
| 1786 | |
| 1787 | EXPORT_SYMBOL(aio_complete); |
| 1788 | EXPORT_SYMBOL(aio_put_req); |
| 1789 | EXPORT_SYMBOL(wait_on_sync_kiocb); |