Root/
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/export.h> |
17 | #include <linux/syscalls.h> |
18 | #include <linux/backing-dev.h> |
19 | #include <linux/uio.h> |
20 | |
21 | #define DEBUG 0 |
22 | |
23 | #include <linux/sched.h> |
24 | #include <linux/fs.h> |
25 | #include <linux/file.h> |
26 | #include <linux/mm.h> |
27 | #include <linux/mman.h> |
28 | #include <linux/mmu_context.h> |
29 | #include <linux/slab.h> |
30 | #include <linux/timer.h> |
31 | #include <linux/aio.h> |
32 | #include <linux/highmem.h> |
33 | #include <linux/workqueue.h> |
34 | #include <linux/security.h> |
35 | #include <linux/eventfd.h> |
36 | #include <linux/blkdev.h> |
37 | #include <linux/compat.h> |
38 | |
39 | #include <asm/kmap_types.h> |
40 | #include <asm/uaccess.h> |
41 | |
42 | #if DEBUG > 1 |
43 | #define dprintk printk |
44 | #else |
45 | #define dprintk(x...) do { ; } while (0) |
46 | #endif |
47 | |
48 | /*------ sysctl variables----*/ |
49 | static DEFINE_SPINLOCK(aio_nr_lock); |
50 | unsigned long aio_nr; /* current system wide number of aio requests */ |
51 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ |
52 | /*----end sysctl variables---*/ |
53 | |
54 | static struct kmem_cache *kiocb_cachep; |
55 | static struct kmem_cache *kioctx_cachep; |
56 | |
57 | static struct workqueue_struct *aio_wq; |
58 | |
59 | static void aio_kick_handler(struct work_struct *); |
60 | static void aio_queue_work(struct kioctx *); |
61 | |
62 | /* aio_setup |
63 | * Creates the slab caches used by the aio routines, panic on |
64 | * failure as this is done early during the boot sequence. |
65 | */ |
66 | static int __init aio_setup(void) |
67 | { |
68 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
69 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
70 | |
71 | aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */ |
72 | BUG_ON(!aio_wq); |
73 | |
74 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
75 | |
76 | return 0; |
77 | } |
78 | __initcall(aio_setup); |
79 | |
80 | static void aio_free_ring(struct kioctx *ctx) |
81 | { |
82 | struct aio_ring_info *info = &ctx->ring_info; |
83 | long i; |
84 | |
85 | for (i=0; i<info->nr_pages; i++) |
86 | put_page(info->ring_pages[i]); |
87 | |
88 | if (info->mmap_size) { |
89 | BUG_ON(ctx->mm != current->mm); |
90 | vm_munmap(info->mmap_base, info->mmap_size); |
91 | } |
92 | |
93 | if (info->ring_pages && info->ring_pages != info->internal_pages) |
94 | kfree(info->ring_pages); |
95 | info->ring_pages = NULL; |
96 | info->nr = 0; |
97 | } |
98 | |
99 | static int aio_setup_ring(struct kioctx *ctx) |
100 | { |
101 | struct aio_ring *ring; |
102 | struct aio_ring_info *info = &ctx->ring_info; |
103 | unsigned nr_events = ctx->max_reqs; |
104 | unsigned long size, populate; |
105 | int nr_pages; |
106 | |
107 | /* Compensate for the ring buffer's head/tail overlap entry */ |
108 | nr_events += 2; /* 1 is required, 2 for good luck */ |
109 | |
110 | size = sizeof(struct aio_ring); |
111 | size += sizeof(struct io_event) * nr_events; |
112 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
113 | |
114 | if (nr_pages < 0) |
115 | return -EINVAL; |
116 | |
117 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
118 | |
119 | info->nr = 0; |
120 | info->ring_pages = info->internal_pages; |
121 | if (nr_pages > AIO_RING_PAGES) { |
122 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
123 | if (!info->ring_pages) |
124 | return -ENOMEM; |
125 | } |
126 | |
127 | info->mmap_size = nr_pages * PAGE_SIZE; |
128 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
129 | down_write(&ctx->mm->mmap_sem); |
130 | info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size, |
131 | PROT_READ|PROT_WRITE, |
132 | MAP_ANONYMOUS|MAP_PRIVATE, 0, |
133 | &populate); |
134 | if (IS_ERR((void *)info->mmap_base)) { |
135 | up_write(&ctx->mm->mmap_sem); |
136 | info->mmap_size = 0; |
137 | aio_free_ring(ctx); |
138 | return -EAGAIN; |
139 | } |
140 | |
141 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
142 | info->nr_pages = get_user_pages(current, ctx->mm, |
143 | info->mmap_base, nr_pages, |
144 | 1, 0, info->ring_pages, NULL); |
145 | up_write(&ctx->mm->mmap_sem); |
146 | |
147 | if (unlikely(info->nr_pages != nr_pages)) { |
148 | aio_free_ring(ctx); |
149 | return -EAGAIN; |
150 | } |
151 | if (populate) |
152 | mm_populate(info->mmap_base, populate); |
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]); |
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); |
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(). 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) ({ \ |
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]); \ |
184 | __event += pos % AIO_EVENTS_PER_PAGE; \ |
185 | __event; \ |
186 | }) |
187 | |
188 | #define put_aio_ring_event(event) do { \ |
189 | struct io_event *__event = (event); \ |
190 | (void)__event; \ |
191 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \ |
192 | } while(0) |
193 | |
194 | static void ctx_rcu_free(struct rcu_head *head) |
195 | { |
196 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); |
197 | kmem_cache_free(kioctx_cachep, ctx); |
198 | } |
199 | |
200 | /* __put_ioctx |
201 | * Called when the last user of an aio context has gone away, |
202 | * and the struct needs to be freed. |
203 | */ |
204 | static void __put_ioctx(struct kioctx *ctx) |
205 | { |
206 | unsigned nr_events = ctx->max_reqs; |
207 | BUG_ON(ctx->reqs_active); |
208 | |
209 | cancel_delayed_work_sync(&ctx->wq); |
210 | aio_free_ring(ctx); |
211 | mmdrop(ctx->mm); |
212 | ctx->mm = NULL; |
213 | if (nr_events) { |
214 | spin_lock(&aio_nr_lock); |
215 | BUG_ON(aio_nr - nr_events > aio_nr); |
216 | aio_nr -= nr_events; |
217 | spin_unlock(&aio_nr_lock); |
218 | } |
219 | pr_debug("__put_ioctx: freeing %p\n", ctx); |
220 | call_rcu(&ctx->rcu_head, ctx_rcu_free); |
221 | } |
222 | |
223 | static inline int try_get_ioctx(struct kioctx *kioctx) |
224 | { |
225 | return atomic_inc_not_zero(&kioctx->users); |
226 | } |
227 | |
228 | static inline void put_ioctx(struct kioctx *kioctx) |
229 | { |
230 | BUG_ON(atomic_read(&kioctx->users) <= 0); |
231 | if (unlikely(atomic_dec_and_test(&kioctx->users))) |
232 | __put_ioctx(kioctx); |
233 | } |
234 | |
235 | /* ioctx_alloc |
236 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
237 | */ |
238 | static struct kioctx *ioctx_alloc(unsigned nr_events) |
239 | { |
240 | struct mm_struct *mm; |
241 | struct kioctx *ctx; |
242 | int err = -ENOMEM; |
243 | |
244 | /* Prevent overflows */ |
245 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
246 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
247 | pr_debug("ENOMEM: nr_events too high\n"); |
248 | return ERR_PTR(-EINVAL); |
249 | } |
250 | |
251 | if (!nr_events || (unsigned long)nr_events > aio_max_nr) |
252 | return ERR_PTR(-EAGAIN); |
253 | |
254 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
255 | if (!ctx) |
256 | return ERR_PTR(-ENOMEM); |
257 | |
258 | ctx->max_reqs = nr_events; |
259 | mm = ctx->mm = current->mm; |
260 | atomic_inc(&mm->mm_count); |
261 | |
262 | atomic_set(&ctx->users, 2); |
263 | spin_lock_init(&ctx->ctx_lock); |
264 | spin_lock_init(&ctx->ring_info.ring_lock); |
265 | init_waitqueue_head(&ctx->wait); |
266 | |
267 | INIT_LIST_HEAD(&ctx->active_reqs); |
268 | INIT_LIST_HEAD(&ctx->run_list); |
269 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); |
270 | |
271 | if (aio_setup_ring(ctx) < 0) |
272 | goto out_freectx; |
273 | |
274 | /* limit the number of system wide aios */ |
275 | spin_lock(&aio_nr_lock); |
276 | if (aio_nr + nr_events > aio_max_nr || |
277 | aio_nr + nr_events < aio_nr) { |
278 | spin_unlock(&aio_nr_lock); |
279 | goto out_cleanup; |
280 | } |
281 | aio_nr += ctx->max_reqs; |
282 | spin_unlock(&aio_nr_lock); |
283 | |
284 | /* now link into global list. */ |
285 | spin_lock(&mm->ioctx_lock); |
286 | hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); |
287 | spin_unlock(&mm->ioctx_lock); |
288 | |
289 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
290 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
291 | return ctx; |
292 | |
293 | out_cleanup: |
294 | err = -EAGAIN; |
295 | aio_free_ring(ctx); |
296 | out_freectx: |
297 | mmdrop(mm); |
298 | kmem_cache_free(kioctx_cachep, ctx); |
299 | dprintk("aio: error allocating ioctx %d\n", err); |
300 | return ERR_PTR(err); |
301 | } |
302 | |
303 | /* kill_ctx |
304 | * Cancels all outstanding aio requests on an aio context. Used |
305 | * when the processes owning a context have all exited to encourage |
306 | * the rapid destruction of the kioctx. |
307 | */ |
308 | static void kill_ctx(struct kioctx *ctx) |
309 | { |
310 | int (*cancel)(struct kiocb *, struct io_event *); |
311 | struct task_struct *tsk = current; |
312 | DECLARE_WAITQUEUE(wait, tsk); |
313 | struct io_event res; |
314 | |
315 | spin_lock_irq(&ctx->ctx_lock); |
316 | ctx->dead = 1; |
317 | while (!list_empty(&ctx->active_reqs)) { |
318 | struct list_head *pos = ctx->active_reqs.next; |
319 | struct kiocb *iocb = list_kiocb(pos); |
320 | list_del_init(&iocb->ki_list); |
321 | cancel = iocb->ki_cancel; |
322 | kiocbSetCancelled(iocb); |
323 | if (cancel) { |
324 | iocb->ki_users++; |
325 | spin_unlock_irq(&ctx->ctx_lock); |
326 | cancel(iocb, &res); |
327 | spin_lock_irq(&ctx->ctx_lock); |
328 | } |
329 | } |
330 | |
331 | if (!ctx->reqs_active) |
332 | goto out; |
333 | |
334 | add_wait_queue(&ctx->wait, &wait); |
335 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
336 | while (ctx->reqs_active) { |
337 | spin_unlock_irq(&ctx->ctx_lock); |
338 | io_schedule(); |
339 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
340 | spin_lock_irq(&ctx->ctx_lock); |
341 | } |
342 | __set_task_state(tsk, TASK_RUNNING); |
343 | remove_wait_queue(&ctx->wait, &wait); |
344 | |
345 | out: |
346 | spin_unlock_irq(&ctx->ctx_lock); |
347 | } |
348 | |
349 | /* wait_on_sync_kiocb: |
350 | * Waits on the given sync kiocb to complete. |
351 | */ |
352 | ssize_t wait_on_sync_kiocb(struct kiocb *iocb) |
353 | { |
354 | while (iocb->ki_users) { |
355 | set_current_state(TASK_UNINTERRUPTIBLE); |
356 | if (!iocb->ki_users) |
357 | break; |
358 | io_schedule(); |
359 | } |
360 | __set_current_state(TASK_RUNNING); |
361 | return iocb->ki_user_data; |
362 | } |
363 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
364 | |
365 | /* exit_aio: called when the last user of mm goes away. At this point, |
366 | * there is no way for any new requests to be submited or any of the |
367 | * io_* syscalls to be called on the context. However, there may be |
368 | * outstanding requests which hold references to the context; as they |
369 | * go away, they will call put_ioctx and release any pinned memory |
370 | * associated with the request (held via struct page * references). |
371 | */ |
372 | void exit_aio(struct mm_struct *mm) |
373 | { |
374 | struct kioctx *ctx; |
375 | |
376 | while (!hlist_empty(&mm->ioctx_list)) { |
377 | ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); |
378 | hlist_del_rcu(&ctx->list); |
379 | |
380 | kill_ctx(ctx); |
381 | |
382 | if (1 != atomic_read(&ctx->users)) |
383 | printk(KERN_DEBUG |
384 | "exit_aio:ioctx still alive: %d %d %d\n", |
385 | atomic_read(&ctx->users), ctx->dead, |
386 | ctx->reqs_active); |
387 | /* |
388 | * We don't need to bother with munmap() here - |
389 | * exit_mmap(mm) is coming and it'll unmap everything. |
390 | * Since aio_free_ring() uses non-zero ->mmap_size |
391 | * as indicator that it needs to unmap the area, |
392 | * just set it to 0; aio_free_ring() is the only |
393 | * place that uses ->mmap_size, so it's safe. |
394 | * That way we get all munmap done to current->mm - |
395 | * all other callers have ctx->mm == current->mm. |
396 | */ |
397 | ctx->ring_info.mmap_size = 0; |
398 | put_ioctx(ctx); |
399 | } |
400 | } |
401 | |
402 | /* aio_get_req |
403 | * Allocate a slot for an aio request. Increments the users count |
404 | * of the kioctx so that the kioctx stays around until all requests are |
405 | * complete. Returns NULL if no requests are free. |
406 | * |
407 | * Returns with kiocb->users set to 2. The io submit code path holds |
408 | * an extra reference while submitting the i/o. |
409 | * This prevents races between the aio code path referencing the |
410 | * req (after submitting it) and aio_complete() freeing the req. |
411 | */ |
412 | static struct kiocb *__aio_get_req(struct kioctx *ctx) |
413 | { |
414 | struct kiocb *req = NULL; |
415 | |
416 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
417 | if (unlikely(!req)) |
418 | return NULL; |
419 | |
420 | req->ki_flags = 0; |
421 | req->ki_users = 2; |
422 | req->ki_key = 0; |
423 | req->ki_ctx = ctx; |
424 | req->ki_cancel = NULL; |
425 | req->ki_retry = NULL; |
426 | req->ki_dtor = NULL; |
427 | req->private = NULL; |
428 | req->ki_iovec = NULL; |
429 | INIT_LIST_HEAD(&req->ki_run_list); |
430 | req->ki_eventfd = NULL; |
431 | |
432 | return req; |
433 | } |
434 | |
435 | /* |
436 | * struct kiocb's are allocated in batches to reduce the number of |
437 | * times the ctx lock is acquired and released. |
438 | */ |
439 | #define KIOCB_BATCH_SIZE 32L |
440 | struct kiocb_batch { |
441 | struct list_head head; |
442 | long count; /* number of requests left to allocate */ |
443 | }; |
444 | |
445 | static void kiocb_batch_init(struct kiocb_batch *batch, long total) |
446 | { |
447 | INIT_LIST_HEAD(&batch->head); |
448 | batch->count = total; |
449 | } |
450 | |
451 | static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch) |
452 | { |
453 | struct kiocb *req, *n; |
454 | |
455 | if (list_empty(&batch->head)) |
456 | return; |
457 | |
458 | spin_lock_irq(&ctx->ctx_lock); |
459 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
460 | list_del(&req->ki_batch); |
461 | list_del(&req->ki_list); |
462 | kmem_cache_free(kiocb_cachep, req); |
463 | ctx->reqs_active--; |
464 | } |
465 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
466 | wake_up_all(&ctx->wait); |
467 | spin_unlock_irq(&ctx->ctx_lock); |
468 | } |
469 | |
470 | /* |
471 | * Allocate a batch of kiocbs. This avoids taking and dropping the |
472 | * context lock a lot during setup. |
473 | */ |
474 | static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) |
475 | { |
476 | unsigned short allocated, to_alloc; |
477 | long avail; |
478 | struct kiocb *req, *n; |
479 | struct aio_ring *ring; |
480 | |
481 | to_alloc = min(batch->count, KIOCB_BATCH_SIZE); |
482 | for (allocated = 0; allocated < to_alloc; allocated++) { |
483 | req = __aio_get_req(ctx); |
484 | if (!req) |
485 | /* allocation failed, go with what we've got */ |
486 | break; |
487 | list_add(&req->ki_batch, &batch->head); |
488 | } |
489 | |
490 | if (allocated == 0) |
491 | goto out; |
492 | |
493 | spin_lock_irq(&ctx->ctx_lock); |
494 | ring = kmap_atomic(ctx->ring_info.ring_pages[0]); |
495 | |
496 | avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active; |
497 | BUG_ON(avail < 0); |
498 | if (avail < allocated) { |
499 | /* Trim back the number of requests. */ |
500 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
501 | list_del(&req->ki_batch); |
502 | kmem_cache_free(kiocb_cachep, req); |
503 | if (--allocated <= avail) |
504 | break; |
505 | } |
506 | } |
507 | |
508 | batch->count -= allocated; |
509 | list_for_each_entry(req, &batch->head, ki_batch) { |
510 | list_add(&req->ki_list, &ctx->active_reqs); |
511 | ctx->reqs_active++; |
512 | } |
513 | |
514 | kunmap_atomic(ring); |
515 | spin_unlock_irq(&ctx->ctx_lock); |
516 | |
517 | out: |
518 | return allocated; |
519 | } |
520 | |
521 | static inline struct kiocb *aio_get_req(struct kioctx *ctx, |
522 | struct kiocb_batch *batch) |
523 | { |
524 | struct kiocb *req; |
525 | |
526 | if (list_empty(&batch->head)) |
527 | if (kiocb_batch_refill(ctx, batch) == 0) |
528 | return NULL; |
529 | req = list_first_entry(&batch->head, struct kiocb, ki_batch); |
530 | list_del(&req->ki_batch); |
531 | return req; |
532 | } |
533 | |
534 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
535 | { |
536 | assert_spin_locked(&ctx->ctx_lock); |
537 | |
538 | if (req->ki_eventfd != NULL) |
539 | eventfd_ctx_put(req->ki_eventfd); |
540 | if (req->ki_dtor) |
541 | req->ki_dtor(req); |
542 | if (req->ki_iovec != &req->ki_inline_vec) |
543 | kfree(req->ki_iovec); |
544 | kmem_cache_free(kiocb_cachep, req); |
545 | ctx->reqs_active--; |
546 | |
547 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
548 | wake_up_all(&ctx->wait); |
549 | } |
550 | |
551 | /* __aio_put_req |
552 | * Returns true if this put was the last user of the request. |
553 | */ |
554 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
555 | { |
556 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", |
557 | req, atomic_long_read(&req->ki_filp->f_count)); |
558 | |
559 | assert_spin_locked(&ctx->ctx_lock); |
560 | |
561 | req->ki_users--; |
562 | BUG_ON(req->ki_users < 0); |
563 | if (likely(req->ki_users)) |
564 | return 0; |
565 | list_del(&req->ki_list); /* remove from active_reqs */ |
566 | req->ki_cancel = NULL; |
567 | req->ki_retry = NULL; |
568 | |
569 | fput(req->ki_filp); |
570 | req->ki_filp = NULL; |
571 | really_put_req(ctx, req); |
572 | return 1; |
573 | } |
574 | |
575 | /* aio_put_req |
576 | * Returns true if this put was the last user of the kiocb, |
577 | * false if the request is still in use. |
578 | */ |
579 | int aio_put_req(struct kiocb *req) |
580 | { |
581 | struct kioctx *ctx = req->ki_ctx; |
582 | int ret; |
583 | spin_lock_irq(&ctx->ctx_lock); |
584 | ret = __aio_put_req(ctx, req); |
585 | spin_unlock_irq(&ctx->ctx_lock); |
586 | return ret; |
587 | } |
588 | EXPORT_SYMBOL(aio_put_req); |
589 | |
590 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
591 | { |
592 | struct mm_struct *mm = current->mm; |
593 | struct kioctx *ctx, *ret = NULL; |
594 | |
595 | rcu_read_lock(); |
596 | |
597 | hlist_for_each_entry_rcu(ctx, &mm->ioctx_list, list) { |
598 | /* |
599 | * RCU protects us against accessing freed memory but |
600 | * we have to be careful not to get a reference when the |
601 | * reference count already dropped to 0 (ctx->dead test |
602 | * is unreliable because of races). |
603 | */ |
604 | if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){ |
605 | ret = ctx; |
606 | break; |
607 | } |
608 | } |
609 | |
610 | rcu_read_unlock(); |
611 | return ret; |
612 | } |
613 | |
614 | /* |
615 | * Queue up a kiocb to be retried. Assumes that the kiocb |
616 | * has already been marked as kicked, and places it on |
617 | * the retry run list for the corresponding ioctx, if it |
618 | * isn't already queued. Returns 1 if it actually queued |
619 | * the kiocb (to tell the caller to activate the work |
620 | * queue to process it), or 0, if it found that it was |
621 | * already queued. |
622 | */ |
623 | static inline int __queue_kicked_iocb(struct kiocb *iocb) |
624 | { |
625 | struct kioctx *ctx = iocb->ki_ctx; |
626 | |
627 | assert_spin_locked(&ctx->ctx_lock); |
628 | |
629 | if (list_empty(&iocb->ki_run_list)) { |
630 | list_add_tail(&iocb->ki_run_list, |
631 | &ctx->run_list); |
632 | return 1; |
633 | } |
634 | return 0; |
635 | } |
636 | |
637 | /* aio_run_iocb |
638 | * This is the core aio execution routine. It is |
639 | * invoked both for initial i/o submission and |
640 | * subsequent retries via the aio_kick_handler. |
641 | * Expects to be invoked with iocb->ki_ctx->lock |
642 | * already held. The lock is released and reacquired |
643 | * as needed during processing. |
644 | * |
645 | * Calls the iocb retry method (already setup for the |
646 | * iocb on initial submission) for operation specific |
647 | * handling, but takes care of most of common retry |
648 | * execution details for a given iocb. The retry method |
649 | * needs to be non-blocking as far as possible, to avoid |
650 | * holding up other iocbs waiting to be serviced by the |
651 | * retry kernel thread. |
652 | * |
653 | * The trickier parts in this code have to do with |
654 | * ensuring that only one retry instance is in progress |
655 | * for a given iocb at any time. Providing that guarantee |
656 | * simplifies the coding of individual aio operations as |
657 | * it avoids various potential races. |
658 | */ |
659 | static ssize_t aio_run_iocb(struct kiocb *iocb) |
660 | { |
661 | struct kioctx *ctx = iocb->ki_ctx; |
662 | ssize_t (*retry)(struct kiocb *); |
663 | ssize_t ret; |
664 | |
665 | if (!(retry = iocb->ki_retry)) { |
666 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
667 | return 0; |
668 | } |
669 | |
670 | /* |
671 | * We don't want the next retry iteration for this |
672 | * operation to start until this one has returned and |
673 | * updated the iocb state. However, wait_queue functions |
674 | * can trigger a kick_iocb from interrupt context in the |
675 | * meantime, indicating that data is available for the next |
676 | * iteration. We want to remember that and enable the |
677 | * next retry iteration _after_ we are through with |
678 | * this one. |
679 | * |
680 | * So, in order to be able to register a "kick", but |
681 | * prevent it from being queued now, we clear the kick |
682 | * flag, but make the kick code *think* that the iocb is |
683 | * still on the run list until we are actually done. |
684 | * When we are done with this iteration, we check if |
685 | * the iocb was kicked in the meantime and if so, queue |
686 | * it up afresh. |
687 | */ |
688 | |
689 | kiocbClearKicked(iocb); |
690 | |
691 | /* |
692 | * This is so that aio_complete knows it doesn't need to |
693 | * pull the iocb off the run list (We can't just call |
694 | * INIT_LIST_HEAD because we don't want a kick_iocb to |
695 | * queue this on the run list yet) |
696 | */ |
697 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
698 | spin_unlock_irq(&ctx->ctx_lock); |
699 | |
700 | /* Quit retrying if the i/o has been cancelled */ |
701 | if (kiocbIsCancelled(iocb)) { |
702 | ret = -EINTR; |
703 | aio_complete(iocb, ret, 0); |
704 | /* must not access the iocb after this */ |
705 | goto out; |
706 | } |
707 | |
708 | /* |
709 | * Now we are all set to call the retry method in async |
710 | * context. |
711 | */ |
712 | ret = retry(iocb); |
713 | |
714 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
715 | /* |
716 | * There's no easy way to restart the syscall since other AIO's |
717 | * may be already running. Just fail this IO with EINTR. |
718 | */ |
719 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || |
720 | ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK)) |
721 | ret = -EINTR; |
722 | aio_complete(iocb, ret, 0); |
723 | } |
724 | out: |
725 | spin_lock_irq(&ctx->ctx_lock); |
726 | |
727 | if (-EIOCBRETRY == ret) { |
728 | /* |
729 | * OK, now that we are done with this iteration |
730 | * and know that there is more left to go, |
731 | * this is where we let go so that a subsequent |
732 | * "kick" can start the next iteration |
733 | */ |
734 | |
735 | /* will make __queue_kicked_iocb succeed from here on */ |
736 | INIT_LIST_HEAD(&iocb->ki_run_list); |
737 | /* we must queue the next iteration ourselves, if it |
738 | * has already been kicked */ |
739 | if (kiocbIsKicked(iocb)) { |
740 | __queue_kicked_iocb(iocb); |
741 | |
742 | /* |
743 | * __queue_kicked_iocb will always return 1 here, because |
744 | * iocb->ki_run_list is empty at this point so it should |
745 | * be safe to unconditionally queue the context into the |
746 | * work queue. |
747 | */ |
748 | aio_queue_work(ctx); |
749 | } |
750 | } |
751 | return ret; |
752 | } |
753 | |
754 | /* |
755 | * __aio_run_iocbs: |
756 | * Process all pending retries queued on the ioctx |
757 | * run list. |
758 | * Assumes it is operating within the aio issuer's mm |
759 | * context. |
760 | */ |
761 | static int __aio_run_iocbs(struct kioctx *ctx) |
762 | { |
763 | struct kiocb *iocb; |
764 | struct list_head run_list; |
765 | |
766 | assert_spin_locked(&ctx->ctx_lock); |
767 | |
768 | list_replace_init(&ctx->run_list, &run_list); |
769 | while (!list_empty(&run_list)) { |
770 | iocb = list_entry(run_list.next, struct kiocb, |
771 | ki_run_list); |
772 | list_del(&iocb->ki_run_list); |
773 | /* |
774 | * Hold an extra reference while retrying i/o. |
775 | */ |
776 | iocb->ki_users++; /* grab extra reference */ |
777 | aio_run_iocb(iocb); |
778 | __aio_put_req(ctx, iocb); |
779 | } |
780 | if (!list_empty(&ctx->run_list)) |
781 | return 1; |
782 | return 0; |
783 | } |
784 | |
785 | static void aio_queue_work(struct kioctx * ctx) |
786 | { |
787 | unsigned long timeout; |
788 | /* |
789 | * if someone is waiting, get the work started right |
790 | * away, otherwise, use a longer delay |
791 | */ |
792 | smp_mb(); |
793 | if (waitqueue_active(&ctx->wait)) |
794 | timeout = 1; |
795 | else |
796 | timeout = HZ/10; |
797 | queue_delayed_work(aio_wq, &ctx->wq, timeout); |
798 | } |
799 | |
800 | /* |
801 | * aio_run_all_iocbs: |
802 | * Process all pending retries queued on the ioctx |
803 | * run list, and keep running them until the list |
804 | * stays empty. |
805 | * Assumes it is operating within the aio issuer's mm context. |
806 | */ |
807 | static inline void aio_run_all_iocbs(struct kioctx *ctx) |
808 | { |
809 | spin_lock_irq(&ctx->ctx_lock); |
810 | while (__aio_run_iocbs(ctx)) |
811 | ; |
812 | spin_unlock_irq(&ctx->ctx_lock); |
813 | } |
814 | |
815 | /* |
816 | * aio_kick_handler: |
817 | * Work queue handler triggered to process pending |
818 | * retries on an ioctx. Takes on the aio issuer's |
819 | * mm context before running the iocbs, so that |
820 | * copy_xxx_user operates on the issuer's address |
821 | * space. |
822 | * Run on aiod's context. |
823 | */ |
824 | static void aio_kick_handler(struct work_struct *work) |
825 | { |
826 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); |
827 | mm_segment_t oldfs = get_fs(); |
828 | struct mm_struct *mm; |
829 | int requeue; |
830 | |
831 | set_fs(USER_DS); |
832 | use_mm(ctx->mm); |
833 | spin_lock_irq(&ctx->ctx_lock); |
834 | requeue =__aio_run_iocbs(ctx); |
835 | mm = ctx->mm; |
836 | spin_unlock_irq(&ctx->ctx_lock); |
837 | unuse_mm(mm); |
838 | set_fs(oldfs); |
839 | /* |
840 | * we're in a worker thread already; no point using non-zero delay |
841 | */ |
842 | if (requeue) |
843 | queue_delayed_work(aio_wq, &ctx->wq, 0); |
844 | } |
845 | |
846 | |
847 | /* |
848 | * Called by kick_iocb to queue the kiocb for retry |
849 | * and if required activate the aio work queue to process |
850 | * it |
851 | */ |
852 | static void try_queue_kicked_iocb(struct kiocb *iocb) |
853 | { |
854 | struct kioctx *ctx = iocb->ki_ctx; |
855 | unsigned long flags; |
856 | int run = 0; |
857 | |
858 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
859 | /* set this inside the lock so that we can't race with aio_run_iocb() |
860 | * testing it and putting the iocb on the run list under the lock */ |
861 | if (!kiocbTryKick(iocb)) |
862 | run = __queue_kicked_iocb(iocb); |
863 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
864 | if (run) |
865 | aio_queue_work(ctx); |
866 | } |
867 | |
868 | /* |
869 | * kick_iocb: |
870 | * Called typically from a wait queue callback context |
871 | * to trigger a retry of the iocb. |
872 | * The retry is usually executed by aio workqueue |
873 | * threads (See aio_kick_handler). |
874 | */ |
875 | void kick_iocb(struct kiocb *iocb) |
876 | { |
877 | /* sync iocbs are easy: they can only ever be executing from a |
878 | * single context. */ |
879 | if (is_sync_kiocb(iocb)) { |
880 | kiocbSetKicked(iocb); |
881 | wake_up_process(iocb->ki_obj.tsk); |
882 | return; |
883 | } |
884 | |
885 | try_queue_kicked_iocb(iocb); |
886 | } |
887 | EXPORT_SYMBOL(kick_iocb); |
888 | |
889 | /* aio_complete |
890 | * Called when the io request on the given iocb is complete. |
891 | * Returns true if this is the last user of the request. The |
892 | * only other user of the request can be the cancellation code. |
893 | */ |
894 | int aio_complete(struct kiocb *iocb, long res, long res2) |
895 | { |
896 | struct kioctx *ctx = iocb->ki_ctx; |
897 | struct aio_ring_info *info; |
898 | struct aio_ring *ring; |
899 | struct io_event *event; |
900 | unsigned long flags; |
901 | unsigned long tail; |
902 | int ret; |
903 | |
904 | /* |
905 | * Special case handling for sync iocbs: |
906 | * - events go directly into the iocb for fast handling |
907 | * - the sync task with the iocb in its stack holds the single iocb |
908 | * ref, no other paths have a way to get another ref |
909 | * - the sync task helpfully left a reference to itself in the iocb |
910 | */ |
911 | if (is_sync_kiocb(iocb)) { |
912 | BUG_ON(iocb->ki_users != 1); |
913 | iocb->ki_user_data = res; |
914 | iocb->ki_users = 0; |
915 | wake_up_process(iocb->ki_obj.tsk); |
916 | return 1; |
917 | } |
918 | |
919 | info = &ctx->ring_info; |
920 | |
921 | /* add a completion event to the ring buffer. |
922 | * must be done holding ctx->ctx_lock to prevent |
923 | * other code from messing with the tail |
924 | * pointer since we might be called from irq |
925 | * context. |
926 | */ |
927 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
928 | |
929 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
930 | list_del_init(&iocb->ki_run_list); |
931 | |
932 | /* |
933 | * cancelled requests don't get events, userland was given one |
934 | * when the event got cancelled. |
935 | */ |
936 | if (kiocbIsCancelled(iocb)) |
937 | goto put_rq; |
938 | |
939 | ring = kmap_atomic(info->ring_pages[0]); |
940 | |
941 | tail = info->tail; |
942 | event = aio_ring_event(info, tail); |
943 | if (++tail >= info->nr) |
944 | tail = 0; |
945 | |
946 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
947 | event->data = iocb->ki_user_data; |
948 | event->res = res; |
949 | event->res2 = res2; |
950 | |
951 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
952 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
953 | res, res2); |
954 | |
955 | /* after flagging the request as done, we |
956 | * must never even look at it again |
957 | */ |
958 | smp_wmb(); /* make event visible before updating tail */ |
959 | |
960 | info->tail = tail; |
961 | ring->tail = tail; |
962 | |
963 | put_aio_ring_event(event); |
964 | kunmap_atomic(ring); |
965 | |
966 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); |
967 | |
968 | /* |
969 | * Check if the user asked us to deliver the result through an |
970 | * eventfd. The eventfd_signal() function is safe to be called |
971 | * from IRQ context. |
972 | */ |
973 | if (iocb->ki_eventfd != NULL) |
974 | eventfd_signal(iocb->ki_eventfd, 1); |
975 | |
976 | put_rq: |
977 | /* everything turned out well, dispose of the aiocb. */ |
978 | ret = __aio_put_req(ctx, iocb); |
979 | |
980 | /* |
981 | * We have to order our ring_info tail store above and test |
982 | * of the wait list below outside the wait lock. This is |
983 | * like in wake_up_bit() where clearing a bit has to be |
984 | * ordered with the unlocked test. |
985 | */ |
986 | smp_mb(); |
987 | |
988 | if (waitqueue_active(&ctx->wait)) |
989 | wake_up(&ctx->wait); |
990 | |
991 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
992 | return ret; |
993 | } |
994 | EXPORT_SYMBOL(aio_complete); |
995 | |
996 | /* aio_read_evt |
997 | * Pull an event off of the ioctx's event ring. Returns the number of |
998 | * events fetched (0 or 1 ;-) |
999 | * FIXME: make this use cmpxchg. |
1000 | * TODO: make the ringbuffer user mmap()able (requires FIXME). |
1001 | */ |
1002 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
1003 | { |
1004 | struct aio_ring_info *info = &ioctx->ring_info; |
1005 | struct aio_ring *ring; |
1006 | unsigned long head; |
1007 | int ret = 0; |
1008 | |
1009 | ring = kmap_atomic(info->ring_pages[0]); |
1010 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
1011 | (unsigned long)ring->head, (unsigned long)ring->tail, |
1012 | (unsigned long)ring->nr); |
1013 | |
1014 | if (ring->head == ring->tail) |
1015 | goto out; |
1016 | |
1017 | spin_lock(&info->ring_lock); |
1018 | |
1019 | head = ring->head % info->nr; |
1020 | if (head != ring->tail) { |
1021 | struct io_event *evp = aio_ring_event(info, head); |
1022 | *ent = *evp; |
1023 | head = (head + 1) % info->nr; |
1024 | smp_mb(); /* finish reading the event before updatng the head */ |
1025 | ring->head = head; |
1026 | ret = 1; |
1027 | put_aio_ring_event(evp); |
1028 | } |
1029 | spin_unlock(&info->ring_lock); |
1030 | |
1031 | out: |
1032 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
1033 | (unsigned long)ring->head, (unsigned long)ring->tail); |
1034 | kunmap_atomic(ring); |
1035 | return ret; |
1036 | } |
1037 | |
1038 | struct aio_timeout { |
1039 | struct timer_list timer; |
1040 | int timed_out; |
1041 | struct task_struct *p; |
1042 | }; |
1043 | |
1044 | static void timeout_func(unsigned long data) |
1045 | { |
1046 | struct aio_timeout *to = (struct aio_timeout *)data; |
1047 | |
1048 | to->timed_out = 1; |
1049 | wake_up_process(to->p); |
1050 | } |
1051 | |
1052 | static inline void init_timeout(struct aio_timeout *to) |
1053 | { |
1054 | setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); |
1055 | to->timed_out = 0; |
1056 | to->p = current; |
1057 | } |
1058 | |
1059 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
1060 | const struct timespec *ts) |
1061 | { |
1062 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
1063 | if (time_after(to->timer.expires, jiffies)) |
1064 | add_timer(&to->timer); |
1065 | else |
1066 | to->timed_out = 1; |
1067 | } |
1068 | |
1069 | static inline void clear_timeout(struct aio_timeout *to) |
1070 | { |
1071 | del_singleshot_timer_sync(&to->timer); |
1072 | } |
1073 | |
1074 | static int read_events(struct kioctx *ctx, |
1075 | long min_nr, long nr, |
1076 | struct io_event __user *event, |
1077 | struct timespec __user *timeout) |
1078 | { |
1079 | long start_jiffies = jiffies; |
1080 | struct task_struct *tsk = current; |
1081 | DECLARE_WAITQUEUE(wait, tsk); |
1082 | int ret; |
1083 | int i = 0; |
1084 | struct io_event ent; |
1085 | struct aio_timeout to; |
1086 | int retry = 0; |
1087 | |
1088 | /* needed to zero any padding within an entry (there shouldn't be |
1089 | * any, but C is fun! |
1090 | */ |
1091 | memset(&ent, 0, sizeof(ent)); |
1092 | retry: |
1093 | ret = 0; |
1094 | while (likely(i < nr)) { |
1095 | ret = aio_read_evt(ctx, &ent); |
1096 | if (unlikely(ret <= 0)) |
1097 | break; |
1098 | |
1099 | dprintk("read event: %Lx %Lx %Lx %Lx\n", |
1100 | ent.data, ent.obj, ent.res, ent.res2); |
1101 | |
1102 | /* Could we split the check in two? */ |
1103 | ret = -EFAULT; |
1104 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1105 | dprintk("aio: lost an event due to EFAULT.\n"); |
1106 | break; |
1107 | } |
1108 | ret = 0; |
1109 | |
1110 | /* Good, event copied to userland, update counts. */ |
1111 | event ++; |
1112 | i ++; |
1113 | } |
1114 | |
1115 | if (min_nr <= i) |
1116 | return i; |
1117 | if (ret) |
1118 | return ret; |
1119 | |
1120 | /* End fast path */ |
1121 | |
1122 | /* racey check, but it gets redone */ |
1123 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
1124 | retry = 1; |
1125 | aio_run_all_iocbs(ctx); |
1126 | goto retry; |
1127 | } |
1128 | |
1129 | init_timeout(&to); |
1130 | if (timeout) { |
1131 | struct timespec ts; |
1132 | ret = -EFAULT; |
1133 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
1134 | goto out; |
1135 | |
1136 | set_timeout(start_jiffies, &to, &ts); |
1137 | } |
1138 | |
1139 | while (likely(i < nr)) { |
1140 | add_wait_queue_exclusive(&ctx->wait, &wait); |
1141 | do { |
1142 | set_task_state(tsk, TASK_INTERRUPTIBLE); |
1143 | ret = aio_read_evt(ctx, &ent); |
1144 | if (ret) |
1145 | break; |
1146 | if (min_nr <= i) |
1147 | break; |
1148 | if (unlikely(ctx->dead)) { |
1149 | ret = -EINVAL; |
1150 | break; |
1151 | } |
1152 | if (to.timed_out) /* Only check after read evt */ |
1153 | break; |
1154 | /* Try to only show up in io wait if there are ops |
1155 | * in flight */ |
1156 | if (ctx->reqs_active) |
1157 | io_schedule(); |
1158 | else |
1159 | schedule(); |
1160 | if (signal_pending(tsk)) { |
1161 | ret = -EINTR; |
1162 | break; |
1163 | } |
1164 | /*ret = aio_read_evt(ctx, &ent);*/ |
1165 | } while (1) ; |
1166 | |
1167 | set_task_state(tsk, TASK_RUNNING); |
1168 | remove_wait_queue(&ctx->wait, &wait); |
1169 | |
1170 | if (unlikely(ret <= 0)) |
1171 | break; |
1172 | |
1173 | ret = -EFAULT; |
1174 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1175 | dprintk("aio: lost an event due to EFAULT.\n"); |
1176 | break; |
1177 | } |
1178 | |
1179 | /* Good, event copied to userland, update counts. */ |
1180 | event ++; |
1181 | i ++; |
1182 | } |
1183 | |
1184 | if (timeout) |
1185 | clear_timeout(&to); |
1186 | out: |
1187 | destroy_timer_on_stack(&to.timer); |
1188 | return i ? i : ret; |
1189 | } |
1190 | |
1191 | /* Take an ioctx and remove it from the list of ioctx's. Protects |
1192 | * against races with itself via ->dead. |
1193 | */ |
1194 | static void io_destroy(struct kioctx *ioctx) |
1195 | { |
1196 | struct mm_struct *mm = current->mm; |
1197 | int was_dead; |
1198 | |
1199 | /* delete the entry from the list is someone else hasn't already */ |
1200 | spin_lock(&mm->ioctx_lock); |
1201 | was_dead = ioctx->dead; |
1202 | ioctx->dead = 1; |
1203 | hlist_del_rcu(&ioctx->list); |
1204 | spin_unlock(&mm->ioctx_lock); |
1205 | |
1206 | dprintk("aio_release(%p)\n", ioctx); |
1207 | if (likely(!was_dead)) |
1208 | put_ioctx(ioctx); /* twice for the list */ |
1209 | |
1210 | kill_ctx(ioctx); |
1211 | |
1212 | /* |
1213 | * Wake up any waiters. The setting of ctx->dead must be seen |
1214 | * by other CPUs at this point. Right now, we rely on the |
1215 | * locking done by the above calls to ensure this consistency. |
1216 | */ |
1217 | wake_up_all(&ioctx->wait); |
1218 | } |
1219 | |
1220 | /* sys_io_setup: |
1221 | * Create an aio_context capable of receiving at least nr_events. |
1222 | * ctxp must not point to an aio_context that already exists, and |
1223 | * must be initialized to 0 prior to the call. On successful |
1224 | * creation of the aio_context, *ctxp is filled in with the resulting |
1225 | * handle. May fail with -EINVAL if *ctxp is not initialized, |
1226 | * if the specified nr_events exceeds internal limits. May fail |
1227 | * with -EAGAIN if the specified nr_events exceeds the user's limit |
1228 | * of available events. May fail with -ENOMEM if insufficient kernel |
1229 | * resources are available. May fail with -EFAULT if an invalid |
1230 | * pointer is passed for ctxp. Will fail with -ENOSYS if not |
1231 | * implemented. |
1232 | */ |
1233 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1234 | { |
1235 | struct kioctx *ioctx = NULL; |
1236 | unsigned long ctx; |
1237 | long ret; |
1238 | |
1239 | ret = get_user(ctx, ctxp); |
1240 | if (unlikely(ret)) |
1241 | goto out; |
1242 | |
1243 | ret = -EINVAL; |
1244 | if (unlikely(ctx || nr_events == 0)) { |
1245 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", |
1246 | ctx, nr_events); |
1247 | goto out; |
1248 | } |
1249 | |
1250 | ioctx = ioctx_alloc(nr_events); |
1251 | ret = PTR_ERR(ioctx); |
1252 | if (!IS_ERR(ioctx)) { |
1253 | ret = put_user(ioctx->user_id, ctxp); |
1254 | if (ret) |
1255 | io_destroy(ioctx); |
1256 | put_ioctx(ioctx); |
1257 | } |
1258 | |
1259 | out: |
1260 | return ret; |
1261 | } |
1262 | |
1263 | /* sys_io_destroy: |
1264 | * Destroy the aio_context specified. May cancel any outstanding |
1265 | * AIOs and block on completion. Will fail with -ENOSYS if not |
1266 | * implemented. May fail with -EINVAL if the context pointed to |
1267 | * is invalid. |
1268 | */ |
1269 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1270 | { |
1271 | struct kioctx *ioctx = lookup_ioctx(ctx); |
1272 | if (likely(NULL != ioctx)) { |
1273 | io_destroy(ioctx); |
1274 | put_ioctx(ioctx); |
1275 | return 0; |
1276 | } |
1277 | pr_debug("EINVAL: io_destroy: invalid context id\n"); |
1278 | return -EINVAL; |
1279 | } |
1280 | |
1281 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) |
1282 | { |
1283 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; |
1284 | |
1285 | BUG_ON(ret <= 0); |
1286 | |
1287 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { |
1288 | ssize_t this = min((ssize_t)iov->iov_len, ret); |
1289 | iov->iov_base += this; |
1290 | iov->iov_len -= this; |
1291 | iocb->ki_left -= this; |
1292 | ret -= this; |
1293 | if (iov->iov_len == 0) { |
1294 | iocb->ki_cur_seg++; |
1295 | iov++; |
1296 | } |
1297 | } |
1298 | |
1299 | /* the caller should not have done more io than what fit in |
1300 | * the remaining iovecs */ |
1301 | BUG_ON(ret > 0 && iocb->ki_left == 0); |
1302 | } |
1303 | |
1304 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) |
1305 | { |
1306 | struct file *file = iocb->ki_filp; |
1307 | struct address_space *mapping = file->f_mapping; |
1308 | struct inode *inode = mapping->host; |
1309 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, |
1310 | unsigned long, loff_t); |
1311 | ssize_t ret = 0; |
1312 | unsigned short opcode; |
1313 | |
1314 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || |
1315 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { |
1316 | rw_op = file->f_op->aio_read; |
1317 | opcode = IOCB_CMD_PREADV; |
1318 | } else { |
1319 | rw_op = file->f_op->aio_write; |
1320 | opcode = IOCB_CMD_PWRITEV; |
1321 | } |
1322 | |
1323 | /* This matches the pread()/pwrite() logic */ |
1324 | if (iocb->ki_pos < 0) |
1325 | return -EINVAL; |
1326 | |
1327 | do { |
1328 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], |
1329 | iocb->ki_nr_segs - iocb->ki_cur_seg, |
1330 | iocb->ki_pos); |
1331 | if (ret > 0) |
1332 | aio_advance_iovec(iocb, ret); |
1333 | |
1334 | /* retry all partial writes. retry partial reads as long as its a |
1335 | * regular file. */ |
1336 | } while (ret > 0 && iocb->ki_left > 0 && |
1337 | (opcode == IOCB_CMD_PWRITEV || |
1338 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); |
1339 | |
1340 | /* This means we must have transferred all that we could */ |
1341 | /* No need to retry anymore */ |
1342 | if ((ret == 0) || (iocb->ki_left == 0)) |
1343 | ret = iocb->ki_nbytes - iocb->ki_left; |
1344 | |
1345 | /* If we managed to write some out we return that, rather than |
1346 | * the eventual error. */ |
1347 | if (opcode == IOCB_CMD_PWRITEV |
1348 | && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY |
1349 | && iocb->ki_nbytes - iocb->ki_left) |
1350 | ret = iocb->ki_nbytes - iocb->ki_left; |
1351 | |
1352 | return ret; |
1353 | } |
1354 | |
1355 | static ssize_t aio_fdsync(struct kiocb *iocb) |
1356 | { |
1357 | struct file *file = iocb->ki_filp; |
1358 | ssize_t ret = -EINVAL; |
1359 | |
1360 | if (file->f_op->aio_fsync) |
1361 | ret = file->f_op->aio_fsync(iocb, 1); |
1362 | return ret; |
1363 | } |
1364 | |
1365 | static ssize_t aio_fsync(struct kiocb *iocb) |
1366 | { |
1367 | struct file *file = iocb->ki_filp; |
1368 | ssize_t ret = -EINVAL; |
1369 | |
1370 | if (file->f_op->aio_fsync) |
1371 | ret = file->f_op->aio_fsync(iocb, 0); |
1372 | return ret; |
1373 | } |
1374 | |
1375 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat) |
1376 | { |
1377 | ssize_t ret; |
1378 | |
1379 | #ifdef CONFIG_COMPAT |
1380 | if (compat) |
1381 | ret = compat_rw_copy_check_uvector(type, |
1382 | (struct compat_iovec __user *)kiocb->ki_buf, |
1383 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1384 | &kiocb->ki_iovec); |
1385 | else |
1386 | #endif |
1387 | ret = rw_copy_check_uvector(type, |
1388 | (struct iovec __user *)kiocb->ki_buf, |
1389 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1390 | &kiocb->ki_iovec); |
1391 | if (ret < 0) |
1392 | goto out; |
1393 | |
1394 | ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret); |
1395 | if (ret < 0) |
1396 | goto out; |
1397 | |
1398 | kiocb->ki_nr_segs = kiocb->ki_nbytes; |
1399 | kiocb->ki_cur_seg = 0; |
1400 | /* ki_nbytes/left now reflect bytes instead of segs */ |
1401 | kiocb->ki_nbytes = ret; |
1402 | kiocb->ki_left = ret; |
1403 | |
1404 | ret = 0; |
1405 | out: |
1406 | return ret; |
1407 | } |
1408 | |
1409 | static ssize_t aio_setup_single_vector(int type, struct file * file, struct kiocb *kiocb) |
1410 | { |
1411 | int bytes; |
1412 | |
1413 | bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left); |
1414 | if (bytes < 0) |
1415 | return bytes; |
1416 | |
1417 | kiocb->ki_iovec = &kiocb->ki_inline_vec; |
1418 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; |
1419 | kiocb->ki_iovec->iov_len = bytes; |
1420 | kiocb->ki_nr_segs = 1; |
1421 | kiocb->ki_cur_seg = 0; |
1422 | return 0; |
1423 | } |
1424 | |
1425 | /* |
1426 | * aio_setup_iocb: |
1427 | * Performs the initial checks and aio retry method |
1428 | * setup for the kiocb at the time of io submission. |
1429 | */ |
1430 | static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) |
1431 | { |
1432 | struct file *file = kiocb->ki_filp; |
1433 | ssize_t ret = 0; |
1434 | |
1435 | switch (kiocb->ki_opcode) { |
1436 | case IOCB_CMD_PREAD: |
1437 | ret = -EBADF; |
1438 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1439 | break; |
1440 | ret = -EFAULT; |
1441 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
1442 | kiocb->ki_left))) |
1443 | break; |
1444 | ret = aio_setup_single_vector(READ, file, kiocb); |
1445 | if (ret) |
1446 | break; |
1447 | ret = -EINVAL; |
1448 | if (file->f_op->aio_read) |
1449 | kiocb->ki_retry = aio_rw_vect_retry; |
1450 | break; |
1451 | case IOCB_CMD_PWRITE: |
1452 | ret = -EBADF; |
1453 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1454 | break; |
1455 | ret = -EFAULT; |
1456 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
1457 | kiocb->ki_left))) |
1458 | break; |
1459 | ret = aio_setup_single_vector(WRITE, file, kiocb); |
1460 | if (ret) |
1461 | break; |
1462 | ret = -EINVAL; |
1463 | if (file->f_op->aio_write) |
1464 | kiocb->ki_retry = aio_rw_vect_retry; |
1465 | break; |
1466 | case IOCB_CMD_PREADV: |
1467 | ret = -EBADF; |
1468 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1469 | break; |
1470 | ret = aio_setup_vectored_rw(READ, kiocb, compat); |
1471 | if (ret) |
1472 | break; |
1473 | ret = -EINVAL; |
1474 | if (file->f_op->aio_read) |
1475 | kiocb->ki_retry = aio_rw_vect_retry; |
1476 | break; |
1477 | case IOCB_CMD_PWRITEV: |
1478 | ret = -EBADF; |
1479 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1480 | break; |
1481 | ret = aio_setup_vectored_rw(WRITE, kiocb, compat); |
1482 | if (ret) |
1483 | break; |
1484 | ret = -EINVAL; |
1485 | if (file->f_op->aio_write) |
1486 | kiocb->ki_retry = aio_rw_vect_retry; |
1487 | break; |
1488 | case IOCB_CMD_FDSYNC: |
1489 | ret = -EINVAL; |
1490 | if (file->f_op->aio_fsync) |
1491 | kiocb->ki_retry = aio_fdsync; |
1492 | break; |
1493 | case IOCB_CMD_FSYNC: |
1494 | ret = -EINVAL; |
1495 | if (file->f_op->aio_fsync) |
1496 | kiocb->ki_retry = aio_fsync; |
1497 | break; |
1498 | default: |
1499 | dprintk("EINVAL: io_submit: no operation provided\n"); |
1500 | ret = -EINVAL; |
1501 | } |
1502 | |
1503 | if (!kiocb->ki_retry) |
1504 | return ret; |
1505 | |
1506 | return 0; |
1507 | } |
1508 | |
1509 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
1510 | struct iocb *iocb, struct kiocb_batch *batch, |
1511 | bool compat) |
1512 | { |
1513 | struct kiocb *req; |
1514 | struct file *file; |
1515 | ssize_t ret; |
1516 | |
1517 | /* enforce forwards compatibility on users */ |
1518 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
1519 | pr_debug("EINVAL: io_submit: reserve field set\n"); |
1520 | return -EINVAL; |
1521 | } |
1522 | |
1523 | /* prevent overflows */ |
1524 | if (unlikely( |
1525 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || |
1526 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || |
1527 | ((ssize_t)iocb->aio_nbytes < 0) |
1528 | )) { |
1529 | pr_debug("EINVAL: io_submit: overflow check\n"); |
1530 | return -EINVAL; |
1531 | } |
1532 | |
1533 | file = fget(iocb->aio_fildes); |
1534 | if (unlikely(!file)) |
1535 | return -EBADF; |
1536 | |
1537 | req = aio_get_req(ctx, batch); /* returns with 2 references to req */ |
1538 | if (unlikely(!req)) { |
1539 | fput(file); |
1540 | return -EAGAIN; |
1541 | } |
1542 | req->ki_filp = file; |
1543 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1544 | /* |
1545 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an |
1546 | * instance of the file* now. The file descriptor must be |
1547 | * an eventfd() fd, and will be signaled for each completed |
1548 | * event using the eventfd_signal() function. |
1549 | */ |
1550 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
1551 | if (IS_ERR(req->ki_eventfd)) { |
1552 | ret = PTR_ERR(req->ki_eventfd); |
1553 | req->ki_eventfd = NULL; |
1554 | goto out_put_req; |
1555 | } |
1556 | } |
1557 | |
1558 | ret = put_user(req->ki_key, &user_iocb->aio_key); |
1559 | if (unlikely(ret)) { |
1560 | dprintk("EFAULT: aio_key\n"); |
1561 | goto out_put_req; |
1562 | } |
1563 | |
1564 | req->ki_obj.user = user_iocb; |
1565 | req->ki_user_data = iocb->aio_data; |
1566 | req->ki_pos = iocb->aio_offset; |
1567 | |
1568 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
1569 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
1570 | req->ki_opcode = iocb->aio_lio_opcode; |
1571 | |
1572 | ret = aio_setup_iocb(req, compat); |
1573 | |
1574 | if (ret) |
1575 | goto out_put_req; |
1576 | |
1577 | spin_lock_irq(&ctx->ctx_lock); |
1578 | /* |
1579 | * We could have raced with io_destroy() and are currently holding a |
1580 | * reference to ctx which should be destroyed. We cannot submit IO |
1581 | * since ctx gets freed as soon as io_submit() puts its reference. The |
1582 | * check here is reliable: io_destroy() sets ctx->dead before waiting |
1583 | * for outstanding IO and the barrier between these two is realized by |
1584 | * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we |
1585 | * increment ctx->reqs_active before checking for ctx->dead and the |
1586 | * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we |
1587 | * don't see ctx->dead set here, io_destroy() waits for our IO to |
1588 | * finish. |
1589 | */ |
1590 | if (ctx->dead) { |
1591 | spin_unlock_irq(&ctx->ctx_lock); |
1592 | ret = -EINVAL; |
1593 | goto out_put_req; |
1594 | } |
1595 | aio_run_iocb(req); |
1596 | if (!list_empty(&ctx->run_list)) { |
1597 | /* drain the run list */ |
1598 | while (__aio_run_iocbs(ctx)) |
1599 | ; |
1600 | } |
1601 | spin_unlock_irq(&ctx->ctx_lock); |
1602 | |
1603 | aio_put_req(req); /* drop extra ref to req */ |
1604 | return 0; |
1605 | |
1606 | out_put_req: |
1607 | aio_put_req(req); /* drop extra ref to req */ |
1608 | aio_put_req(req); /* drop i/o ref to req */ |
1609 | return ret; |
1610 | } |
1611 | |
1612 | long do_io_submit(aio_context_t ctx_id, long nr, |
1613 | struct iocb __user *__user *iocbpp, bool compat) |
1614 | { |
1615 | struct kioctx *ctx; |
1616 | long ret = 0; |
1617 | int i = 0; |
1618 | struct blk_plug plug; |
1619 | struct kiocb_batch batch; |
1620 | |
1621 | if (unlikely(nr < 0)) |
1622 | return -EINVAL; |
1623 | |
1624 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1625 | nr = LONG_MAX/sizeof(*iocbpp); |
1626 | |
1627 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1628 | return -EFAULT; |
1629 | |
1630 | ctx = lookup_ioctx(ctx_id); |
1631 | if (unlikely(!ctx)) { |
1632 | pr_debug("EINVAL: io_submit: invalid context id\n"); |
1633 | return -EINVAL; |
1634 | } |
1635 | |
1636 | kiocb_batch_init(&batch, nr); |
1637 | |
1638 | blk_start_plug(&plug); |
1639 | |
1640 | /* |
1641 | * AKPM: should this return a partial result if some of the IOs were |
1642 | * successfully submitted? |
1643 | */ |
1644 | for (i=0; i<nr; i++) { |
1645 | struct iocb __user *user_iocb; |
1646 | struct iocb tmp; |
1647 | |
1648 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
1649 | ret = -EFAULT; |
1650 | break; |
1651 | } |
1652 | |
1653 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
1654 | ret = -EFAULT; |
1655 | break; |
1656 | } |
1657 | |
1658 | ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat); |
1659 | if (ret) |
1660 | break; |
1661 | } |
1662 | blk_finish_plug(&plug); |
1663 | |
1664 | kiocb_batch_free(ctx, &batch); |
1665 | put_ioctx(ctx); |
1666 | return i ? i : ret; |
1667 | } |
1668 | |
1669 | /* sys_io_submit: |
1670 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns |
1671 | * the number of iocbs queued. May return -EINVAL if the aio_context |
1672 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at |
1673 | * *iocbpp[0] is not properly initialized, if the operation specified |
1674 | * is invalid for the file descriptor in the iocb. May fail with |
1675 | * -EFAULT if any of the data structures point to invalid data. May |
1676 | * fail with -EBADF if the file descriptor specified in the first |
1677 | * iocb is invalid. May fail with -EAGAIN if insufficient resources |
1678 | * are available to queue any iocbs. Will return 0 if nr is 0. Will |
1679 | * fail with -ENOSYS if not implemented. |
1680 | */ |
1681 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, |
1682 | struct iocb __user * __user *, iocbpp) |
1683 | { |
1684 | return do_io_submit(ctx_id, nr, iocbpp, 0); |
1685 | } |
1686 | |
1687 | /* lookup_kiocb |
1688 | * Finds a given iocb for cancellation. |
1689 | */ |
1690 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1691 | u32 key) |
1692 | { |
1693 | struct list_head *pos; |
1694 | |
1695 | assert_spin_locked(&ctx->ctx_lock); |
1696 | |
1697 | /* TODO: use a hash or array, this sucks. */ |
1698 | list_for_each(pos, &ctx->active_reqs) { |
1699 | struct kiocb *kiocb = list_kiocb(pos); |
1700 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
1701 | return kiocb; |
1702 | } |
1703 | return NULL; |
1704 | } |
1705 | |
1706 | /* sys_io_cancel: |
1707 | * Attempts to cancel an iocb previously passed to io_submit. If |
1708 | * the operation is successfully cancelled, the resulting event is |
1709 | * copied into the memory pointed to by result without being placed |
1710 | * into the completion queue and 0 is returned. May fail with |
1711 | * -EFAULT if any of the data structures pointed to are invalid. |
1712 | * May fail with -EINVAL if aio_context specified by ctx_id is |
1713 | * invalid. May fail with -EAGAIN if the iocb specified was not |
1714 | * cancelled. Will fail with -ENOSYS if not implemented. |
1715 | */ |
1716 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1717 | struct io_event __user *, result) |
1718 | { |
1719 | int (*cancel)(struct kiocb *iocb, struct io_event *res); |
1720 | struct kioctx *ctx; |
1721 | struct kiocb *kiocb; |
1722 | u32 key; |
1723 | int ret; |
1724 | |
1725 | ret = get_user(key, &iocb->aio_key); |
1726 | if (unlikely(ret)) |
1727 | return -EFAULT; |
1728 | |
1729 | ctx = lookup_ioctx(ctx_id); |
1730 | if (unlikely(!ctx)) |
1731 | return -EINVAL; |
1732 | |
1733 | spin_lock_irq(&ctx->ctx_lock); |
1734 | ret = -EAGAIN; |
1735 | kiocb = lookup_kiocb(ctx, iocb, key); |
1736 | if (kiocb && kiocb->ki_cancel) { |
1737 | cancel = kiocb->ki_cancel; |
1738 | kiocb->ki_users ++; |
1739 | kiocbSetCancelled(kiocb); |
1740 | } else |
1741 | cancel = NULL; |
1742 | spin_unlock_irq(&ctx->ctx_lock); |
1743 | |
1744 | if (NULL != cancel) { |
1745 | struct io_event tmp; |
1746 | pr_debug("calling cancel\n"); |
1747 | memset(&tmp, 0, sizeof(tmp)); |
1748 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
1749 | tmp.data = kiocb->ki_user_data; |
1750 | ret = cancel(kiocb, &tmp); |
1751 | if (!ret) { |
1752 | /* Cancellation succeeded -- copy the result |
1753 | * into the user's buffer. |
1754 | */ |
1755 | if (copy_to_user(result, &tmp, sizeof(tmp))) |
1756 | ret = -EFAULT; |
1757 | } |
1758 | } else |
1759 | ret = -EINVAL; |
1760 | |
1761 | put_ioctx(ctx); |
1762 | |
1763 | return ret; |
1764 | } |
1765 | |
1766 | /* io_getevents: |
1767 | * Attempts to read at least min_nr events and up to nr events from |
1768 | * the completion queue for the aio_context specified by ctx_id. If |
1769 | * it succeeds, the number of read events is returned. May fail with |
1770 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is |
1771 | * out of range, if timeout is out of range. May fail with -EFAULT |
1772 | * if any of the memory specified is invalid. May return 0 or |
1773 | * < min_nr if the timeout specified by timeout has elapsed |
1774 | * before sufficient events are available, where timeout == NULL |
1775 | * specifies an infinite timeout. Note that the timeout pointed to by |
1776 | * timeout is relative and will be updated if not NULL and the |
1777 | * operation blocks. Will fail with -ENOSYS if not implemented. |
1778 | */ |
1779 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1780 | long, min_nr, |
1781 | long, nr, |
1782 | struct io_event __user *, events, |
1783 | struct timespec __user *, timeout) |
1784 | { |
1785 | struct kioctx *ioctx = lookup_ioctx(ctx_id); |
1786 | long ret = -EINVAL; |
1787 | |
1788 | if (likely(ioctx)) { |
1789 | if (likely(min_nr <= nr && min_nr >= 0)) |
1790 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
1791 | put_ioctx(ioctx); |
1792 | } |
1793 | |
1794 | asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); |
1795 | return ret; |
1796 | } |
1797 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9