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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> |
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/mempool.h> |
38 | #include <linux/hash.h> |
39 | #include <linux/compat.h> |
40 | |
41 | #include <asm/kmap_types.h> |
42 | #include <asm/uaccess.h> |
43 | |
44 | #if DEBUG > 1 |
45 | #define dprintk printk |
46 | #else |
47 | #define dprintk(x...) do { ; } while (0) |
48 | #endif |
49 | |
50 | /*------ sysctl variables----*/ |
51 | static DEFINE_SPINLOCK(aio_nr_lock); |
52 | unsigned long aio_nr; /* current system wide number of aio requests */ |
53 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ |
54 | /*----end sysctl variables---*/ |
55 | |
56 | static struct kmem_cache *kiocb_cachep; |
57 | static struct kmem_cache *kioctx_cachep; |
58 | |
59 | static struct workqueue_struct *aio_wq; |
60 | |
61 | /* Used for rare fput completion. */ |
62 | static void aio_fput_routine(struct work_struct *); |
63 | static DECLARE_WORK(fput_work, aio_fput_routine); |
64 | |
65 | static DEFINE_SPINLOCK(fput_lock); |
66 | static LIST_HEAD(fput_head); |
67 | |
68 | #define AIO_BATCH_HASH_BITS 3 /* allocated on-stack, so don't go crazy */ |
69 | #define AIO_BATCH_HASH_SIZE (1 << AIO_BATCH_HASH_BITS) |
70 | struct aio_batch_entry { |
71 | struct hlist_node list; |
72 | struct address_space *mapping; |
73 | }; |
74 | mempool_t *abe_pool; |
75 | |
76 | static void aio_kick_handler(struct work_struct *); |
77 | static void aio_queue_work(struct kioctx *); |
78 | |
79 | /* aio_setup |
80 | * Creates the slab caches used by the aio routines, panic on |
81 | * failure as this is done early during the boot sequence. |
82 | */ |
83 | static int __init aio_setup(void) |
84 | { |
85 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
86 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
87 | |
88 | aio_wq = create_workqueue("aio"); |
89 | abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry)); |
90 | BUG_ON(!abe_pool); |
91 | |
92 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
93 | |
94 | return 0; |
95 | } |
96 | __initcall(aio_setup); |
97 | |
98 | static void aio_free_ring(struct kioctx *ctx) |
99 | { |
100 | struct aio_ring_info *info = &ctx->ring_info; |
101 | long i; |
102 | |
103 | for (i=0; i<info->nr_pages; i++) |
104 | put_page(info->ring_pages[i]); |
105 | |
106 | if (info->mmap_size) { |
107 | down_write(&ctx->mm->mmap_sem); |
108 | do_munmap(ctx->mm, info->mmap_base, info->mmap_size); |
109 | up_write(&ctx->mm->mmap_sem); |
110 | } |
111 | |
112 | if (info->ring_pages && info->ring_pages != info->internal_pages) |
113 | kfree(info->ring_pages); |
114 | info->ring_pages = NULL; |
115 | info->nr = 0; |
116 | } |
117 | |
118 | static int aio_setup_ring(struct kioctx *ctx) |
119 | { |
120 | struct aio_ring *ring; |
121 | struct aio_ring_info *info = &ctx->ring_info; |
122 | unsigned nr_events = ctx->max_reqs; |
123 | unsigned long size; |
124 | int nr_pages; |
125 | |
126 | /* Compensate for the ring buffer's head/tail overlap entry */ |
127 | nr_events += 2; /* 1 is required, 2 for good luck */ |
128 | |
129 | size = sizeof(struct aio_ring); |
130 | size += sizeof(struct io_event) * nr_events; |
131 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
132 | |
133 | if (nr_pages < 0) |
134 | return -EINVAL; |
135 | |
136 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
137 | |
138 | info->nr = 0; |
139 | info->ring_pages = info->internal_pages; |
140 | if (nr_pages > AIO_RING_PAGES) { |
141 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
142 | if (!info->ring_pages) |
143 | return -ENOMEM; |
144 | } |
145 | |
146 | info->mmap_size = nr_pages * PAGE_SIZE; |
147 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
148 | down_write(&ctx->mm->mmap_sem); |
149 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, |
150 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, |
151 | 0); |
152 | if (IS_ERR((void *)info->mmap_base)) { |
153 | up_write(&ctx->mm->mmap_sem); |
154 | info->mmap_size = 0; |
155 | aio_free_ring(ctx); |
156 | return -EAGAIN; |
157 | } |
158 | |
159 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
160 | info->nr_pages = get_user_pages(current, ctx->mm, |
161 | info->mmap_base, nr_pages, |
162 | 1, 0, info->ring_pages, NULL); |
163 | up_write(&ctx->mm->mmap_sem); |
164 | |
165 | if (unlikely(info->nr_pages != nr_pages)) { |
166 | aio_free_ring(ctx); |
167 | return -EAGAIN; |
168 | } |
169 | |
170 | ctx->user_id = info->mmap_base; |
171 | |
172 | info->nr = nr_events; /* trusted copy */ |
173 | |
174 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
175 | ring->nr = nr_events; /* user copy */ |
176 | ring->id = ctx->user_id; |
177 | ring->head = ring->tail = 0; |
178 | ring->magic = AIO_RING_MAGIC; |
179 | ring->compat_features = AIO_RING_COMPAT_FEATURES; |
180 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; |
181 | ring->header_length = sizeof(struct aio_ring); |
182 | kunmap_atomic(ring, KM_USER0); |
183 | |
184 | return 0; |
185 | } |
186 | |
187 | |
188 | /* aio_ring_event: returns a pointer to the event at the given index from |
189 | * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); |
190 | */ |
191 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
192 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) |
193 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) |
194 | |
195 | #define aio_ring_event(info, nr, km) ({ \ |
196 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ |
197 | struct io_event *__event; \ |
198 | __event = kmap_atomic( \ |
199 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ |
200 | __event += pos % AIO_EVENTS_PER_PAGE; \ |
201 | __event; \ |
202 | }) |
203 | |
204 | #define put_aio_ring_event(event, km) do { \ |
205 | struct io_event *__event = (event); \ |
206 | (void)__event; \ |
207 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ |
208 | } while(0) |
209 | |
210 | static void ctx_rcu_free(struct rcu_head *head) |
211 | { |
212 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); |
213 | unsigned nr_events = ctx->max_reqs; |
214 | |
215 | kmem_cache_free(kioctx_cachep, ctx); |
216 | |
217 | if (nr_events) { |
218 | spin_lock(&aio_nr_lock); |
219 | BUG_ON(aio_nr - nr_events > aio_nr); |
220 | aio_nr -= nr_events; |
221 | spin_unlock(&aio_nr_lock); |
222 | } |
223 | } |
224 | |
225 | /* __put_ioctx |
226 | * Called when the last user of an aio context has gone away, |
227 | * and the struct needs to be freed. |
228 | */ |
229 | static void __put_ioctx(struct kioctx *ctx) |
230 | { |
231 | BUG_ON(ctx->reqs_active); |
232 | |
233 | cancel_delayed_work(&ctx->wq); |
234 | cancel_work_sync(&ctx->wq.work); |
235 | aio_free_ring(ctx); |
236 | mmdrop(ctx->mm); |
237 | ctx->mm = NULL; |
238 | pr_debug("__put_ioctx: freeing %p\n", ctx); |
239 | call_rcu(&ctx->rcu_head, ctx_rcu_free); |
240 | } |
241 | |
242 | #define get_ioctx(kioctx) do { \ |
243 | BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ |
244 | atomic_inc(&(kioctx)->users); \ |
245 | } while (0) |
246 | #define put_ioctx(kioctx) do { \ |
247 | BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ |
248 | if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \ |
249 | __put_ioctx(kioctx); \ |
250 | } while (0) |
251 | |
252 | /* ioctx_alloc |
253 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
254 | */ |
255 | static struct kioctx *ioctx_alloc(unsigned nr_events) |
256 | { |
257 | struct mm_struct *mm; |
258 | struct kioctx *ctx; |
259 | int did_sync = 0; |
260 | |
261 | /* Prevent overflows */ |
262 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
263 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
264 | pr_debug("ENOMEM: nr_events too high\n"); |
265 | return ERR_PTR(-EINVAL); |
266 | } |
267 | |
268 | if ((unsigned long)nr_events > aio_max_nr) |
269 | return ERR_PTR(-EAGAIN); |
270 | |
271 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
272 | if (!ctx) |
273 | return ERR_PTR(-ENOMEM); |
274 | |
275 | ctx->max_reqs = nr_events; |
276 | mm = ctx->mm = current->mm; |
277 | atomic_inc(&mm->mm_count); |
278 | |
279 | atomic_set(&ctx->users, 1); |
280 | spin_lock_init(&ctx->ctx_lock); |
281 | spin_lock_init(&ctx->ring_info.ring_lock); |
282 | init_waitqueue_head(&ctx->wait); |
283 | |
284 | INIT_LIST_HEAD(&ctx->active_reqs); |
285 | INIT_LIST_HEAD(&ctx->run_list); |
286 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); |
287 | |
288 | if (aio_setup_ring(ctx) < 0) |
289 | goto out_freectx; |
290 | |
291 | /* limit the number of system wide aios */ |
292 | do { |
293 | spin_lock_bh(&aio_nr_lock); |
294 | if (aio_nr + nr_events > aio_max_nr || |
295 | aio_nr + nr_events < aio_nr) |
296 | ctx->max_reqs = 0; |
297 | else |
298 | aio_nr += ctx->max_reqs; |
299 | spin_unlock_bh(&aio_nr_lock); |
300 | if (ctx->max_reqs || did_sync) |
301 | break; |
302 | |
303 | /* wait for rcu callbacks to have completed before giving up */ |
304 | synchronize_rcu(); |
305 | did_sync = 1; |
306 | ctx->max_reqs = nr_events; |
307 | } while (1); |
308 | |
309 | if (ctx->max_reqs == 0) |
310 | goto out_cleanup; |
311 | |
312 | /* now link into global list. */ |
313 | spin_lock(&mm->ioctx_lock); |
314 | hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); |
315 | spin_unlock(&mm->ioctx_lock); |
316 | |
317 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
318 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
319 | return ctx; |
320 | |
321 | out_cleanup: |
322 | __put_ioctx(ctx); |
323 | return ERR_PTR(-EAGAIN); |
324 | |
325 | out_freectx: |
326 | mmdrop(mm); |
327 | kmem_cache_free(kioctx_cachep, ctx); |
328 | ctx = ERR_PTR(-ENOMEM); |
329 | |
330 | dprintk("aio: error allocating ioctx %p\n", ctx); |
331 | return ctx; |
332 | } |
333 | |
334 | /* aio_cancel_all |
335 | * Cancels all outstanding aio requests on an aio context. Used |
336 | * when the processes owning a context have all exited to encourage |
337 | * the rapid destruction of the kioctx. |
338 | */ |
339 | static void aio_cancel_all(struct kioctx *ctx) |
340 | { |
341 | int (*cancel)(struct kiocb *, struct io_event *); |
342 | struct io_event res; |
343 | spin_lock_irq(&ctx->ctx_lock); |
344 | ctx->dead = 1; |
345 | while (!list_empty(&ctx->active_reqs)) { |
346 | struct list_head *pos = ctx->active_reqs.next; |
347 | struct kiocb *iocb = list_kiocb(pos); |
348 | list_del_init(&iocb->ki_list); |
349 | cancel = iocb->ki_cancel; |
350 | kiocbSetCancelled(iocb); |
351 | if (cancel) { |
352 | iocb->ki_users++; |
353 | spin_unlock_irq(&ctx->ctx_lock); |
354 | cancel(iocb, &res); |
355 | spin_lock_irq(&ctx->ctx_lock); |
356 | } |
357 | } |
358 | spin_unlock_irq(&ctx->ctx_lock); |
359 | } |
360 | |
361 | static void wait_for_all_aios(struct kioctx *ctx) |
362 | { |
363 | struct task_struct *tsk = current; |
364 | DECLARE_WAITQUEUE(wait, tsk); |
365 | |
366 | spin_lock_irq(&ctx->ctx_lock); |
367 | if (!ctx->reqs_active) |
368 | goto out; |
369 | |
370 | add_wait_queue(&ctx->wait, &wait); |
371 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
372 | while (ctx->reqs_active) { |
373 | spin_unlock_irq(&ctx->ctx_lock); |
374 | io_schedule(); |
375 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
376 | spin_lock_irq(&ctx->ctx_lock); |
377 | } |
378 | __set_task_state(tsk, TASK_RUNNING); |
379 | remove_wait_queue(&ctx->wait, &wait); |
380 | |
381 | out: |
382 | spin_unlock_irq(&ctx->ctx_lock); |
383 | } |
384 | |
385 | /* wait_on_sync_kiocb: |
386 | * Waits on the given sync kiocb to complete. |
387 | */ |
388 | ssize_t wait_on_sync_kiocb(struct kiocb *iocb) |
389 | { |
390 | while (iocb->ki_users) { |
391 | set_current_state(TASK_UNINTERRUPTIBLE); |
392 | if (!iocb->ki_users) |
393 | break; |
394 | io_schedule(); |
395 | } |
396 | __set_current_state(TASK_RUNNING); |
397 | return iocb->ki_user_data; |
398 | } |
399 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
400 | |
401 | /* exit_aio: called when the last user of mm goes away. At this point, |
402 | * there is no way for any new requests to be submited or any of the |
403 | * io_* syscalls to be called on the context. However, there may be |
404 | * outstanding requests which hold references to the context; as they |
405 | * go away, they will call put_ioctx and release any pinned memory |
406 | * associated with the request (held via struct page * references). |
407 | */ |
408 | void exit_aio(struct mm_struct *mm) |
409 | { |
410 | struct kioctx *ctx; |
411 | |
412 | while (!hlist_empty(&mm->ioctx_list)) { |
413 | ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); |
414 | hlist_del_rcu(&ctx->list); |
415 | |
416 | aio_cancel_all(ctx); |
417 | |
418 | wait_for_all_aios(ctx); |
419 | /* |
420 | * Ensure we don't leave the ctx on the aio_wq |
421 | */ |
422 | cancel_work_sync(&ctx->wq.work); |
423 | |
424 | if (1 != atomic_read(&ctx->users)) |
425 | printk(KERN_DEBUG |
426 | "exit_aio:ioctx still alive: %d %d %d\n", |
427 | atomic_read(&ctx->users), ctx->dead, |
428 | ctx->reqs_active); |
429 | put_ioctx(ctx); |
430 | } |
431 | } |
432 | |
433 | /* aio_get_req |
434 | * Allocate a slot for an aio request. Increments the users count |
435 | * of the kioctx so that the kioctx stays around until all requests are |
436 | * complete. Returns NULL if no requests are free. |
437 | * |
438 | * Returns with kiocb->users set to 2. The io submit code path holds |
439 | * an extra reference while submitting the i/o. |
440 | * This prevents races between the aio code path referencing the |
441 | * req (after submitting it) and aio_complete() freeing the req. |
442 | */ |
443 | static struct kiocb *__aio_get_req(struct kioctx *ctx) |
444 | { |
445 | struct kiocb *req = NULL; |
446 | struct aio_ring *ring; |
447 | int okay = 0; |
448 | |
449 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
450 | if (unlikely(!req)) |
451 | return NULL; |
452 | |
453 | req->ki_flags = 0; |
454 | req->ki_users = 2; |
455 | req->ki_key = 0; |
456 | req->ki_ctx = ctx; |
457 | req->ki_cancel = NULL; |
458 | req->ki_retry = NULL; |
459 | req->ki_dtor = NULL; |
460 | req->private = NULL; |
461 | req->ki_iovec = NULL; |
462 | INIT_LIST_HEAD(&req->ki_run_list); |
463 | req->ki_eventfd = NULL; |
464 | |
465 | /* Check if the completion queue has enough free space to |
466 | * accept an event from this io. |
467 | */ |
468 | spin_lock_irq(&ctx->ctx_lock); |
469 | ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0); |
470 | if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) { |
471 | list_add(&req->ki_list, &ctx->active_reqs); |
472 | ctx->reqs_active++; |
473 | okay = 1; |
474 | } |
475 | kunmap_atomic(ring, KM_USER0); |
476 | spin_unlock_irq(&ctx->ctx_lock); |
477 | |
478 | if (!okay) { |
479 | kmem_cache_free(kiocb_cachep, req); |
480 | req = NULL; |
481 | } |
482 | |
483 | return req; |
484 | } |
485 | |
486 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) |
487 | { |
488 | struct kiocb *req; |
489 | /* Handle a potential starvation case -- should be exceedingly rare as |
490 | * requests will be stuck on fput_head only if the aio_fput_routine is |
491 | * delayed and the requests were the last user of the struct file. |
492 | */ |
493 | req = __aio_get_req(ctx); |
494 | if (unlikely(NULL == req)) { |
495 | aio_fput_routine(NULL); |
496 | req = __aio_get_req(ctx); |
497 | } |
498 | return req; |
499 | } |
500 | |
501 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
502 | { |
503 | assert_spin_locked(&ctx->ctx_lock); |
504 | |
505 | if (req->ki_eventfd != NULL) |
506 | eventfd_ctx_put(req->ki_eventfd); |
507 | if (req->ki_dtor) |
508 | req->ki_dtor(req); |
509 | if (req->ki_iovec != &req->ki_inline_vec) |
510 | kfree(req->ki_iovec); |
511 | kmem_cache_free(kiocb_cachep, req); |
512 | ctx->reqs_active--; |
513 | |
514 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
515 | wake_up(&ctx->wait); |
516 | } |
517 | |
518 | static void aio_fput_routine(struct work_struct *data) |
519 | { |
520 | spin_lock_irq(&fput_lock); |
521 | while (likely(!list_empty(&fput_head))) { |
522 | struct kiocb *req = list_kiocb(fput_head.next); |
523 | struct kioctx *ctx = req->ki_ctx; |
524 | |
525 | list_del(&req->ki_list); |
526 | spin_unlock_irq(&fput_lock); |
527 | |
528 | /* Complete the fput(s) */ |
529 | if (req->ki_filp != NULL) |
530 | fput(req->ki_filp); |
531 | |
532 | /* Link the iocb into the context's free list */ |
533 | spin_lock_irq(&ctx->ctx_lock); |
534 | really_put_req(ctx, req); |
535 | spin_unlock_irq(&ctx->ctx_lock); |
536 | |
537 | put_ioctx(ctx); |
538 | spin_lock_irq(&fput_lock); |
539 | } |
540 | spin_unlock_irq(&fput_lock); |
541 | } |
542 | |
543 | /* __aio_put_req |
544 | * Returns true if this put was the last user of the request. |
545 | */ |
546 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
547 | { |
548 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", |
549 | req, atomic_long_read(&req->ki_filp->f_count)); |
550 | |
551 | assert_spin_locked(&ctx->ctx_lock); |
552 | |
553 | req->ki_users--; |
554 | BUG_ON(req->ki_users < 0); |
555 | if (likely(req->ki_users)) |
556 | return 0; |
557 | list_del(&req->ki_list); /* remove from active_reqs */ |
558 | req->ki_cancel = NULL; |
559 | req->ki_retry = NULL; |
560 | |
561 | /* |
562 | * Try to optimize the aio and eventfd file* puts, by avoiding to |
563 | * schedule work in case it is not final fput() time. In normal cases, |
564 | * we would not be holding the last reference to the file*, so |
565 | * this function will be executed w/out any aio kthread wakeup. |
566 | */ |
567 | if (unlikely(!fput_atomic(req->ki_filp))) { |
568 | get_ioctx(ctx); |
569 | spin_lock(&fput_lock); |
570 | list_add(&req->ki_list, &fput_head); |
571 | spin_unlock(&fput_lock); |
572 | queue_work(aio_wq, &fput_work); |
573 | } else { |
574 | req->ki_filp = NULL; |
575 | really_put_req(ctx, req); |
576 | } |
577 | return 1; |
578 | } |
579 | |
580 | /* aio_put_req |
581 | * Returns true if this put was the last user of the kiocb, |
582 | * false if the request is still in use. |
583 | */ |
584 | int aio_put_req(struct kiocb *req) |
585 | { |
586 | struct kioctx *ctx = req->ki_ctx; |
587 | int ret; |
588 | spin_lock_irq(&ctx->ctx_lock); |
589 | ret = __aio_put_req(ctx, req); |
590 | spin_unlock_irq(&ctx->ctx_lock); |
591 | return ret; |
592 | } |
593 | EXPORT_SYMBOL(aio_put_req); |
594 | |
595 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
596 | { |
597 | struct mm_struct *mm = current->mm; |
598 | struct kioctx *ctx, *ret = NULL; |
599 | struct hlist_node *n; |
600 | |
601 | rcu_read_lock(); |
602 | |
603 | hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { |
604 | if (ctx->user_id == ctx_id && !ctx->dead) { |
605 | get_ioctx(ctx); |
606 | ret = ctx; |
607 | break; |
608 | } |
609 | } |
610 | |
611 | rcu_read_unlock(); |
612 | return ret; |
613 | } |
614 | |
615 | /* |
616 | * Queue up a kiocb to be retried. Assumes that the kiocb |
617 | * has already been marked as kicked, and places it on |
618 | * the retry run list for the corresponding ioctx, if it |
619 | * isn't already queued. Returns 1 if it actually queued |
620 | * the kiocb (to tell the caller to activate the work |
621 | * queue to process it), or 0, if it found that it was |
622 | * already queued. |
623 | */ |
624 | static inline int __queue_kicked_iocb(struct kiocb *iocb) |
625 | { |
626 | struct kioctx *ctx = iocb->ki_ctx; |
627 | |
628 | assert_spin_locked(&ctx->ctx_lock); |
629 | |
630 | if (list_empty(&iocb->ki_run_list)) { |
631 | list_add_tail(&iocb->ki_run_list, |
632 | &ctx->run_list); |
633 | return 1; |
634 | } |
635 | return 0; |
636 | } |
637 | |
638 | /* aio_run_iocb |
639 | * This is the core aio execution routine. It is |
640 | * invoked both for initial i/o submission and |
641 | * subsequent retries via the aio_kick_handler. |
642 | * Expects to be invoked with iocb->ki_ctx->lock |
643 | * already held. The lock is released and reacquired |
644 | * as needed during processing. |
645 | * |
646 | * Calls the iocb retry method (already setup for the |
647 | * iocb on initial submission) for operation specific |
648 | * handling, but takes care of most of common retry |
649 | * execution details for a given iocb. The retry method |
650 | * needs to be non-blocking as far as possible, to avoid |
651 | * holding up other iocbs waiting to be serviced by the |
652 | * retry kernel thread. |
653 | * |
654 | * The trickier parts in this code have to do with |
655 | * ensuring that only one retry instance is in progress |
656 | * for a given iocb at any time. Providing that guarantee |
657 | * simplifies the coding of individual aio operations as |
658 | * it avoids various potential races. |
659 | */ |
660 | static ssize_t aio_run_iocb(struct kiocb *iocb) |
661 | { |
662 | struct kioctx *ctx = iocb->ki_ctx; |
663 | ssize_t (*retry)(struct kiocb *); |
664 | ssize_t ret; |
665 | |
666 | if (!(retry = iocb->ki_retry)) { |
667 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
668 | return 0; |
669 | } |
670 | |
671 | /* |
672 | * We don't want the next retry iteration for this |
673 | * operation to start until this one has returned and |
674 | * updated the iocb state. However, wait_queue functions |
675 | * can trigger a kick_iocb from interrupt context in the |
676 | * meantime, indicating that data is available for the next |
677 | * iteration. We want to remember that and enable the |
678 | * next retry iteration _after_ we are through with |
679 | * this one. |
680 | * |
681 | * So, in order to be able to register a "kick", but |
682 | * prevent it from being queued now, we clear the kick |
683 | * flag, but make the kick code *think* that the iocb is |
684 | * still on the run list until we are actually done. |
685 | * When we are done with this iteration, we check if |
686 | * the iocb was kicked in the meantime and if so, queue |
687 | * it up afresh. |
688 | */ |
689 | |
690 | kiocbClearKicked(iocb); |
691 | |
692 | /* |
693 | * This is so that aio_complete knows it doesn't need to |
694 | * pull the iocb off the run list (We can't just call |
695 | * INIT_LIST_HEAD because we don't want a kick_iocb to |
696 | * queue this on the run list yet) |
697 | */ |
698 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
699 | spin_unlock_irq(&ctx->ctx_lock); |
700 | |
701 | /* Quit retrying if the i/o has been cancelled */ |
702 | if (kiocbIsCancelled(iocb)) { |
703 | ret = -EINTR; |
704 | aio_complete(iocb, ret, 0); |
705 | /* must not access the iocb after this */ |
706 | goto out; |
707 | } |
708 | |
709 | /* |
710 | * Now we are all set to call the retry method in async |
711 | * context. |
712 | */ |
713 | ret = retry(iocb); |
714 | |
715 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
716 | /* |
717 | * There's no easy way to restart the syscall since other AIO's |
718 | * may be already running. Just fail this IO with EINTR. |
719 | */ |
720 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || |
721 | ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK)) |
722 | ret = -EINTR; |
723 | aio_complete(iocb, ret, 0); |
724 | } |
725 | out: |
726 | spin_lock_irq(&ctx->ctx_lock); |
727 | |
728 | if (-EIOCBRETRY == ret) { |
729 | /* |
730 | * OK, now that we are done with this iteration |
731 | * and know that there is more left to go, |
732 | * this is where we let go so that a subsequent |
733 | * "kick" can start the next iteration |
734 | */ |
735 | |
736 | /* will make __queue_kicked_iocb succeed from here on */ |
737 | INIT_LIST_HEAD(&iocb->ki_run_list); |
738 | /* we must queue the next iteration ourselves, if it |
739 | * has already been kicked */ |
740 | if (kiocbIsKicked(iocb)) { |
741 | __queue_kicked_iocb(iocb); |
742 | |
743 | /* |
744 | * __queue_kicked_iocb will always return 1 here, because |
745 | * iocb->ki_run_list is empty at this point so it should |
746 | * be safe to unconditionally queue the context into the |
747 | * work queue. |
748 | */ |
749 | aio_queue_work(ctx); |
750 | } |
751 | } |
752 | return ret; |
753 | } |
754 | |
755 | /* |
756 | * __aio_run_iocbs: |
757 | * Process all pending retries queued on the ioctx |
758 | * run list. |
759 | * Assumes it is operating within the aio issuer's mm |
760 | * context. |
761 | */ |
762 | static int __aio_run_iocbs(struct kioctx *ctx) |
763 | { |
764 | struct kiocb *iocb; |
765 | struct list_head run_list; |
766 | |
767 | assert_spin_locked(&ctx->ctx_lock); |
768 | |
769 | list_replace_init(&ctx->run_list, &run_list); |
770 | while (!list_empty(&run_list)) { |
771 | iocb = list_entry(run_list.next, struct kiocb, |
772 | ki_run_list); |
773 | list_del(&iocb->ki_run_list); |
774 | /* |
775 | * Hold an extra reference while retrying i/o. |
776 | */ |
777 | iocb->ki_users++; /* grab extra reference */ |
778 | aio_run_iocb(iocb); |
779 | __aio_put_req(ctx, iocb); |
780 | } |
781 | if (!list_empty(&ctx->run_list)) |
782 | return 1; |
783 | return 0; |
784 | } |
785 | |
786 | static void aio_queue_work(struct kioctx * ctx) |
787 | { |
788 | unsigned long timeout; |
789 | /* |
790 | * if someone is waiting, get the work started right |
791 | * away, otherwise, use a longer delay |
792 | */ |
793 | smp_mb(); |
794 | if (waitqueue_active(&ctx->wait)) |
795 | timeout = 1; |
796 | else |
797 | timeout = HZ/10; |
798 | queue_delayed_work(aio_wq, &ctx->wq, timeout); |
799 | } |
800 | |
801 | |
802 | /* |
803 | * aio_run_iocbs: |
804 | * Process all pending retries queued on the ioctx |
805 | * run list. |
806 | * Assumes it is operating within the aio issuer's mm |
807 | * context. |
808 | */ |
809 | static inline void aio_run_iocbs(struct kioctx *ctx) |
810 | { |
811 | int requeue; |
812 | |
813 | spin_lock_irq(&ctx->ctx_lock); |
814 | |
815 | requeue = __aio_run_iocbs(ctx); |
816 | spin_unlock_irq(&ctx->ctx_lock); |
817 | if (requeue) |
818 | aio_queue_work(ctx); |
819 | } |
820 | |
821 | /* |
822 | * just like aio_run_iocbs, but keeps running them until |
823 | * the list stays empty |
824 | */ |
825 | static inline void aio_run_all_iocbs(struct kioctx *ctx) |
826 | { |
827 | spin_lock_irq(&ctx->ctx_lock); |
828 | while (__aio_run_iocbs(ctx)) |
829 | ; |
830 | spin_unlock_irq(&ctx->ctx_lock); |
831 | } |
832 | |
833 | /* |
834 | * aio_kick_handler: |
835 | * Work queue handler triggered to process pending |
836 | * retries on an ioctx. Takes on the aio issuer's |
837 | * mm context before running the iocbs, so that |
838 | * copy_xxx_user operates on the issuer's address |
839 | * space. |
840 | * Run on aiod's context. |
841 | */ |
842 | static void aio_kick_handler(struct work_struct *work) |
843 | { |
844 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); |
845 | mm_segment_t oldfs = get_fs(); |
846 | struct mm_struct *mm; |
847 | int requeue; |
848 | |
849 | set_fs(USER_DS); |
850 | use_mm(ctx->mm); |
851 | spin_lock_irq(&ctx->ctx_lock); |
852 | requeue =__aio_run_iocbs(ctx); |
853 | mm = ctx->mm; |
854 | spin_unlock_irq(&ctx->ctx_lock); |
855 | unuse_mm(mm); |
856 | set_fs(oldfs); |
857 | /* |
858 | * we're in a worker thread already, don't use queue_delayed_work, |
859 | */ |
860 | if (requeue) |
861 | queue_delayed_work(aio_wq, &ctx->wq, 0); |
862 | } |
863 | |
864 | |
865 | /* |
866 | * Called by kick_iocb to queue the kiocb for retry |
867 | * and if required activate the aio work queue to process |
868 | * it |
869 | */ |
870 | static void try_queue_kicked_iocb(struct kiocb *iocb) |
871 | { |
872 | struct kioctx *ctx = iocb->ki_ctx; |
873 | unsigned long flags; |
874 | int run = 0; |
875 | |
876 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
877 | /* set this inside the lock so that we can't race with aio_run_iocb() |
878 | * testing it and putting the iocb on the run list under the lock */ |
879 | if (!kiocbTryKick(iocb)) |
880 | run = __queue_kicked_iocb(iocb); |
881 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
882 | if (run) |
883 | aio_queue_work(ctx); |
884 | } |
885 | |
886 | /* |
887 | * kick_iocb: |
888 | * Called typically from a wait queue callback context |
889 | * to trigger a retry of the iocb. |
890 | * The retry is usually executed by aio workqueue |
891 | * threads (See aio_kick_handler). |
892 | */ |
893 | void kick_iocb(struct kiocb *iocb) |
894 | { |
895 | /* sync iocbs are easy: they can only ever be executing from a |
896 | * single context. */ |
897 | if (is_sync_kiocb(iocb)) { |
898 | kiocbSetKicked(iocb); |
899 | wake_up_process(iocb->ki_obj.tsk); |
900 | return; |
901 | } |
902 | |
903 | try_queue_kicked_iocb(iocb); |
904 | } |
905 | EXPORT_SYMBOL(kick_iocb); |
906 | |
907 | /* aio_complete |
908 | * Called when the io request on the given iocb is complete. |
909 | * Returns true if this is the last user of the request. The |
910 | * only other user of the request can be the cancellation code. |
911 | */ |
912 | int aio_complete(struct kiocb *iocb, long res, long res2) |
913 | { |
914 | struct kioctx *ctx = iocb->ki_ctx; |
915 | struct aio_ring_info *info; |
916 | struct aio_ring *ring; |
917 | struct io_event *event; |
918 | unsigned long flags; |
919 | unsigned long tail; |
920 | int ret; |
921 | |
922 | /* |
923 | * Special case handling for sync iocbs: |
924 | * - events go directly into the iocb for fast handling |
925 | * - the sync task with the iocb in its stack holds the single iocb |
926 | * ref, no other paths have a way to get another ref |
927 | * - the sync task helpfully left a reference to itself in the iocb |
928 | */ |
929 | if (is_sync_kiocb(iocb)) { |
930 | BUG_ON(iocb->ki_users != 1); |
931 | iocb->ki_user_data = res; |
932 | iocb->ki_users = 0; |
933 | wake_up_process(iocb->ki_obj.tsk); |
934 | return 1; |
935 | } |
936 | |
937 | info = &ctx->ring_info; |
938 | |
939 | /* add a completion event to the ring buffer. |
940 | * must be done holding ctx->ctx_lock to prevent |
941 | * other code from messing with the tail |
942 | * pointer since we might be called from irq |
943 | * context. |
944 | */ |
945 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
946 | |
947 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
948 | list_del_init(&iocb->ki_run_list); |
949 | |
950 | /* |
951 | * cancelled requests don't get events, userland was given one |
952 | * when the event got cancelled. |
953 | */ |
954 | if (kiocbIsCancelled(iocb)) |
955 | goto put_rq; |
956 | |
957 | ring = kmap_atomic(info->ring_pages[0], KM_IRQ1); |
958 | |
959 | tail = info->tail; |
960 | event = aio_ring_event(info, tail, KM_IRQ0); |
961 | if (++tail >= info->nr) |
962 | tail = 0; |
963 | |
964 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
965 | event->data = iocb->ki_user_data; |
966 | event->res = res; |
967 | event->res2 = res2; |
968 | |
969 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
970 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
971 | res, res2); |
972 | |
973 | /* after flagging the request as done, we |
974 | * must never even look at it again |
975 | */ |
976 | smp_wmb(); /* make event visible before updating tail */ |
977 | |
978 | info->tail = tail; |
979 | ring->tail = tail; |
980 | |
981 | put_aio_ring_event(event, KM_IRQ0); |
982 | kunmap_atomic(ring, KM_IRQ1); |
983 | |
984 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); |
985 | |
986 | /* |
987 | * Check if the user asked us to deliver the result through an |
988 | * eventfd. The eventfd_signal() function is safe to be called |
989 | * from IRQ context. |
990 | */ |
991 | if (iocb->ki_eventfd != NULL) |
992 | eventfd_signal(iocb->ki_eventfd, 1); |
993 | |
994 | put_rq: |
995 | /* everything turned out well, dispose of the aiocb. */ |
996 | ret = __aio_put_req(ctx, iocb); |
997 | |
998 | /* |
999 | * We have to order our ring_info tail store above and test |
1000 | * of the wait list below outside the wait lock. This is |
1001 | * like in wake_up_bit() where clearing a bit has to be |
1002 | * ordered with the unlocked test. |
1003 | */ |
1004 | smp_mb(); |
1005 | |
1006 | if (waitqueue_active(&ctx->wait)) |
1007 | wake_up(&ctx->wait); |
1008 | |
1009 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
1010 | return ret; |
1011 | } |
1012 | EXPORT_SYMBOL(aio_complete); |
1013 | |
1014 | /* aio_read_evt |
1015 | * Pull an event off of the ioctx's event ring. Returns the number of |
1016 | * events fetched (0 or 1 ;-) |
1017 | * FIXME: make this use cmpxchg. |
1018 | * TODO: make the ringbuffer user mmap()able (requires FIXME). |
1019 | */ |
1020 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
1021 | { |
1022 | struct aio_ring_info *info = &ioctx->ring_info; |
1023 | struct aio_ring *ring; |
1024 | unsigned long head; |
1025 | int ret = 0; |
1026 | |
1027 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
1028 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
1029 | (unsigned long)ring->head, (unsigned long)ring->tail, |
1030 | (unsigned long)ring->nr); |
1031 | |
1032 | if (ring->head == ring->tail) |
1033 | goto out; |
1034 | |
1035 | spin_lock(&info->ring_lock); |
1036 | |
1037 | head = ring->head % info->nr; |
1038 | if (head != ring->tail) { |
1039 | struct io_event *evp = aio_ring_event(info, head, KM_USER1); |
1040 | *ent = *evp; |
1041 | head = (head + 1) % info->nr; |
1042 | smp_mb(); /* finish reading the event before updatng the head */ |
1043 | ring->head = head; |
1044 | ret = 1; |
1045 | put_aio_ring_event(evp, KM_USER1); |
1046 | } |
1047 | spin_unlock(&info->ring_lock); |
1048 | |
1049 | out: |
1050 | kunmap_atomic(ring, KM_USER0); |
1051 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
1052 | (unsigned long)ring->head, (unsigned long)ring->tail); |
1053 | return ret; |
1054 | } |
1055 | |
1056 | struct aio_timeout { |
1057 | struct timer_list timer; |
1058 | int timed_out; |
1059 | struct task_struct *p; |
1060 | }; |
1061 | |
1062 | static void timeout_func(unsigned long data) |
1063 | { |
1064 | struct aio_timeout *to = (struct aio_timeout *)data; |
1065 | |
1066 | to->timed_out = 1; |
1067 | wake_up_process(to->p); |
1068 | } |
1069 | |
1070 | static inline void init_timeout(struct aio_timeout *to) |
1071 | { |
1072 | setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); |
1073 | to->timed_out = 0; |
1074 | to->p = current; |
1075 | } |
1076 | |
1077 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
1078 | const struct timespec *ts) |
1079 | { |
1080 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
1081 | if (time_after(to->timer.expires, jiffies)) |
1082 | add_timer(&to->timer); |
1083 | else |
1084 | to->timed_out = 1; |
1085 | } |
1086 | |
1087 | static inline void clear_timeout(struct aio_timeout *to) |
1088 | { |
1089 | del_singleshot_timer_sync(&to->timer); |
1090 | } |
1091 | |
1092 | static int read_events(struct kioctx *ctx, |
1093 | long min_nr, long nr, |
1094 | struct io_event __user *event, |
1095 | struct timespec __user *timeout) |
1096 | { |
1097 | long start_jiffies = jiffies; |
1098 | struct task_struct *tsk = current; |
1099 | DECLARE_WAITQUEUE(wait, tsk); |
1100 | int ret; |
1101 | int i = 0; |
1102 | struct io_event ent; |
1103 | struct aio_timeout to; |
1104 | int retry = 0; |
1105 | |
1106 | /* needed to zero any padding within an entry (there shouldn't be |
1107 | * any, but C is fun! |
1108 | */ |
1109 | memset(&ent, 0, sizeof(ent)); |
1110 | retry: |
1111 | ret = 0; |
1112 | while (likely(i < nr)) { |
1113 | ret = aio_read_evt(ctx, &ent); |
1114 | if (unlikely(ret <= 0)) |
1115 | break; |
1116 | |
1117 | dprintk("read event: %Lx %Lx %Lx %Lx\n", |
1118 | ent.data, ent.obj, ent.res, ent.res2); |
1119 | |
1120 | /* Could we split the check in two? */ |
1121 | ret = -EFAULT; |
1122 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1123 | dprintk("aio: lost an event due to EFAULT.\n"); |
1124 | break; |
1125 | } |
1126 | ret = 0; |
1127 | |
1128 | /* Good, event copied to userland, update counts. */ |
1129 | event ++; |
1130 | i ++; |
1131 | } |
1132 | |
1133 | if (min_nr <= i) |
1134 | return i; |
1135 | if (ret) |
1136 | return ret; |
1137 | |
1138 | /* End fast path */ |
1139 | |
1140 | /* racey check, but it gets redone */ |
1141 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
1142 | retry = 1; |
1143 | aio_run_all_iocbs(ctx); |
1144 | goto retry; |
1145 | } |
1146 | |
1147 | init_timeout(&to); |
1148 | if (timeout) { |
1149 | struct timespec ts; |
1150 | ret = -EFAULT; |
1151 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
1152 | goto out; |
1153 | |
1154 | set_timeout(start_jiffies, &to, &ts); |
1155 | } |
1156 | |
1157 | while (likely(i < nr)) { |
1158 | add_wait_queue_exclusive(&ctx->wait, &wait); |
1159 | do { |
1160 | set_task_state(tsk, TASK_INTERRUPTIBLE); |
1161 | ret = aio_read_evt(ctx, &ent); |
1162 | if (ret) |
1163 | break; |
1164 | if (min_nr <= i) |
1165 | break; |
1166 | if (unlikely(ctx->dead)) { |
1167 | ret = -EINVAL; |
1168 | break; |
1169 | } |
1170 | if (to.timed_out) /* Only check after read evt */ |
1171 | break; |
1172 | /* Try to only show up in io wait if there are ops |
1173 | * in flight */ |
1174 | if (ctx->reqs_active) |
1175 | io_schedule(); |
1176 | else |
1177 | schedule(); |
1178 | if (signal_pending(tsk)) { |
1179 | ret = -EINTR; |
1180 | break; |
1181 | } |
1182 | /*ret = aio_read_evt(ctx, &ent);*/ |
1183 | } while (1) ; |
1184 | |
1185 | set_task_state(tsk, TASK_RUNNING); |
1186 | remove_wait_queue(&ctx->wait, &wait); |
1187 | |
1188 | if (unlikely(ret <= 0)) |
1189 | break; |
1190 | |
1191 | ret = -EFAULT; |
1192 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1193 | dprintk("aio: lost an event due to EFAULT.\n"); |
1194 | break; |
1195 | } |
1196 | |
1197 | /* Good, event copied to userland, update counts. */ |
1198 | event ++; |
1199 | i ++; |
1200 | } |
1201 | |
1202 | if (timeout) |
1203 | clear_timeout(&to); |
1204 | out: |
1205 | destroy_timer_on_stack(&to.timer); |
1206 | return i ? i : ret; |
1207 | } |
1208 | |
1209 | /* Take an ioctx and remove it from the list of ioctx's. Protects |
1210 | * against races with itself via ->dead. |
1211 | */ |
1212 | static void io_destroy(struct kioctx *ioctx) |
1213 | { |
1214 | struct mm_struct *mm = current->mm; |
1215 | int was_dead; |
1216 | |
1217 | /* delete the entry from the list is someone else hasn't already */ |
1218 | spin_lock(&mm->ioctx_lock); |
1219 | was_dead = ioctx->dead; |
1220 | ioctx->dead = 1; |
1221 | hlist_del_rcu(&ioctx->list); |
1222 | spin_unlock(&mm->ioctx_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 | |
1231 | /* |
1232 | * Wake up any waiters. The setting of ctx->dead must be seen |
1233 | * by other CPUs at this point. Right now, we rely on the |
1234 | * locking done by the above calls to ensure this consistency. |
1235 | */ |
1236 | wake_up(&ioctx->wait); |
1237 | put_ioctx(ioctx); /* once for the lookup */ |
1238 | } |
1239 | |
1240 | /* sys_io_setup: |
1241 | * Create an aio_context capable of receiving at least nr_events. |
1242 | * ctxp must not point to an aio_context that already exists, and |
1243 | * must be initialized to 0 prior to the call. On successful |
1244 | * creation of the aio_context, *ctxp is filled in with the resulting |
1245 | * handle. May fail with -EINVAL if *ctxp is not initialized, |
1246 | * if the specified nr_events exceeds internal limits. May fail |
1247 | * with -EAGAIN if the specified nr_events exceeds the user's limit |
1248 | * of available events. May fail with -ENOMEM if insufficient kernel |
1249 | * resources are available. May fail with -EFAULT if an invalid |
1250 | * pointer is passed for ctxp. Will fail with -ENOSYS if not |
1251 | * implemented. |
1252 | */ |
1253 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1254 | { |
1255 | struct kioctx *ioctx = NULL; |
1256 | unsigned long ctx; |
1257 | long ret; |
1258 | |
1259 | ret = get_user(ctx, ctxp); |
1260 | if (unlikely(ret)) |
1261 | goto out; |
1262 | |
1263 | ret = -EINVAL; |
1264 | if (unlikely(ctx || nr_events == 0)) { |
1265 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", |
1266 | ctx, nr_events); |
1267 | goto out; |
1268 | } |
1269 | |
1270 | ioctx = ioctx_alloc(nr_events); |
1271 | ret = PTR_ERR(ioctx); |
1272 | if (!IS_ERR(ioctx)) { |
1273 | ret = put_user(ioctx->user_id, ctxp); |
1274 | if (!ret) |
1275 | return 0; |
1276 | |
1277 | get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ |
1278 | io_destroy(ioctx); |
1279 | } |
1280 | |
1281 | out: |
1282 | return ret; |
1283 | } |
1284 | |
1285 | /* sys_io_destroy: |
1286 | * Destroy the aio_context specified. May cancel any outstanding |
1287 | * AIOs and block on completion. Will fail with -ENOSYS if not |
1288 | * implemented. May fail with -EINVAL if the context pointed to |
1289 | * is invalid. |
1290 | */ |
1291 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1292 | { |
1293 | struct kioctx *ioctx = lookup_ioctx(ctx); |
1294 | if (likely(NULL != ioctx)) { |
1295 | io_destroy(ioctx); |
1296 | return 0; |
1297 | } |
1298 | pr_debug("EINVAL: io_destroy: invalid context id\n"); |
1299 | return -EINVAL; |
1300 | } |
1301 | |
1302 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) |
1303 | { |
1304 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; |
1305 | |
1306 | BUG_ON(ret <= 0); |
1307 | |
1308 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { |
1309 | ssize_t this = min((ssize_t)iov->iov_len, ret); |
1310 | iov->iov_base += this; |
1311 | iov->iov_len -= this; |
1312 | iocb->ki_left -= this; |
1313 | ret -= this; |
1314 | if (iov->iov_len == 0) { |
1315 | iocb->ki_cur_seg++; |
1316 | iov++; |
1317 | } |
1318 | } |
1319 | |
1320 | /* the caller should not have done more io than what fit in |
1321 | * the remaining iovecs */ |
1322 | BUG_ON(ret > 0 && iocb->ki_left == 0); |
1323 | } |
1324 | |
1325 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) |
1326 | { |
1327 | struct file *file = iocb->ki_filp; |
1328 | struct address_space *mapping = file->f_mapping; |
1329 | struct inode *inode = mapping->host; |
1330 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, |
1331 | unsigned long, loff_t); |
1332 | ssize_t ret = 0; |
1333 | unsigned short opcode; |
1334 | |
1335 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || |
1336 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { |
1337 | rw_op = file->f_op->aio_read; |
1338 | opcode = IOCB_CMD_PREADV; |
1339 | } else { |
1340 | rw_op = file->f_op->aio_write; |
1341 | opcode = IOCB_CMD_PWRITEV; |
1342 | } |
1343 | |
1344 | /* This matches the pread()/pwrite() logic */ |
1345 | if (iocb->ki_pos < 0) |
1346 | return -EINVAL; |
1347 | |
1348 | do { |
1349 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], |
1350 | iocb->ki_nr_segs - iocb->ki_cur_seg, |
1351 | iocb->ki_pos); |
1352 | if (ret > 0) |
1353 | aio_advance_iovec(iocb, ret); |
1354 | |
1355 | /* retry all partial writes. retry partial reads as long as its a |
1356 | * regular file. */ |
1357 | } while (ret > 0 && iocb->ki_left > 0 && |
1358 | (opcode == IOCB_CMD_PWRITEV || |
1359 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); |
1360 | |
1361 | /* This means we must have transferred all that we could */ |
1362 | /* No need to retry anymore */ |
1363 | if ((ret == 0) || (iocb->ki_left == 0)) |
1364 | ret = iocb->ki_nbytes - iocb->ki_left; |
1365 | |
1366 | /* If we managed to write some out we return that, rather than |
1367 | * the eventual error. */ |
1368 | if (opcode == IOCB_CMD_PWRITEV |
1369 | && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY |
1370 | && iocb->ki_nbytes - iocb->ki_left) |
1371 | ret = iocb->ki_nbytes - iocb->ki_left; |
1372 | |
1373 | return ret; |
1374 | } |
1375 | |
1376 | static ssize_t aio_fdsync(struct kiocb *iocb) |
1377 | { |
1378 | struct file *file = iocb->ki_filp; |
1379 | ssize_t ret = -EINVAL; |
1380 | |
1381 | if (file->f_op->aio_fsync) |
1382 | ret = file->f_op->aio_fsync(iocb, 1); |
1383 | return ret; |
1384 | } |
1385 | |
1386 | static ssize_t aio_fsync(struct kiocb *iocb) |
1387 | { |
1388 | struct file *file = iocb->ki_filp; |
1389 | ssize_t ret = -EINVAL; |
1390 | |
1391 | if (file->f_op->aio_fsync) |
1392 | ret = file->f_op->aio_fsync(iocb, 0); |
1393 | return ret; |
1394 | } |
1395 | |
1396 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat) |
1397 | { |
1398 | ssize_t ret; |
1399 | |
1400 | #ifdef CONFIG_COMPAT |
1401 | if (compat) |
1402 | ret = compat_rw_copy_check_uvector(type, |
1403 | (struct compat_iovec __user *)kiocb->ki_buf, |
1404 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1405 | &kiocb->ki_iovec); |
1406 | else |
1407 | #endif |
1408 | ret = rw_copy_check_uvector(type, |
1409 | (struct iovec __user *)kiocb->ki_buf, |
1410 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1411 | &kiocb->ki_iovec); |
1412 | if (ret < 0) |
1413 | goto out; |
1414 | |
1415 | kiocb->ki_nr_segs = kiocb->ki_nbytes; |
1416 | kiocb->ki_cur_seg = 0; |
1417 | /* ki_nbytes/left now reflect bytes instead of segs */ |
1418 | kiocb->ki_nbytes = ret; |
1419 | kiocb->ki_left = ret; |
1420 | |
1421 | ret = 0; |
1422 | out: |
1423 | return ret; |
1424 | } |
1425 | |
1426 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb) |
1427 | { |
1428 | kiocb->ki_iovec = &kiocb->ki_inline_vec; |
1429 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; |
1430 | kiocb->ki_iovec->iov_len = kiocb->ki_left; |
1431 | kiocb->ki_nr_segs = 1; |
1432 | kiocb->ki_cur_seg = 0; |
1433 | return 0; |
1434 | } |
1435 | |
1436 | /* |
1437 | * aio_setup_iocb: |
1438 | * Performs the initial checks and aio retry method |
1439 | * setup for the kiocb at the time of io submission. |
1440 | */ |
1441 | static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) |
1442 | { |
1443 | struct file *file = kiocb->ki_filp; |
1444 | ssize_t ret = 0; |
1445 | |
1446 | switch (kiocb->ki_opcode) { |
1447 | case IOCB_CMD_PREAD: |
1448 | ret = -EBADF; |
1449 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1450 | break; |
1451 | ret = -EFAULT; |
1452 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
1453 | kiocb->ki_left))) |
1454 | break; |
1455 | ret = security_file_permission(file, MAY_READ); |
1456 | if (unlikely(ret)) |
1457 | break; |
1458 | ret = aio_setup_single_vector(kiocb); |
1459 | if (ret) |
1460 | break; |
1461 | ret = -EINVAL; |
1462 | if (file->f_op->aio_read) |
1463 | kiocb->ki_retry = aio_rw_vect_retry; |
1464 | break; |
1465 | case IOCB_CMD_PWRITE: |
1466 | ret = -EBADF; |
1467 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1468 | break; |
1469 | ret = -EFAULT; |
1470 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
1471 | kiocb->ki_left))) |
1472 | break; |
1473 | ret = security_file_permission(file, MAY_WRITE); |
1474 | if (unlikely(ret)) |
1475 | break; |
1476 | ret = aio_setup_single_vector(kiocb); |
1477 | if (ret) |
1478 | break; |
1479 | ret = -EINVAL; |
1480 | if (file->f_op->aio_write) |
1481 | kiocb->ki_retry = aio_rw_vect_retry; |
1482 | break; |
1483 | case IOCB_CMD_PREADV: |
1484 | ret = -EBADF; |
1485 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1486 | break; |
1487 | ret = security_file_permission(file, MAY_READ); |
1488 | if (unlikely(ret)) |
1489 | break; |
1490 | ret = aio_setup_vectored_rw(READ, kiocb, compat); |
1491 | if (ret) |
1492 | break; |
1493 | ret = -EINVAL; |
1494 | if (file->f_op->aio_read) |
1495 | kiocb->ki_retry = aio_rw_vect_retry; |
1496 | break; |
1497 | case IOCB_CMD_PWRITEV: |
1498 | ret = -EBADF; |
1499 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1500 | break; |
1501 | ret = security_file_permission(file, MAY_WRITE); |
1502 | if (unlikely(ret)) |
1503 | break; |
1504 | ret = aio_setup_vectored_rw(WRITE, kiocb, compat); |
1505 | if (ret) |
1506 | break; |
1507 | ret = -EINVAL; |
1508 | if (file->f_op->aio_write) |
1509 | kiocb->ki_retry = aio_rw_vect_retry; |
1510 | break; |
1511 | case IOCB_CMD_FDSYNC: |
1512 | ret = -EINVAL; |
1513 | if (file->f_op->aio_fsync) |
1514 | kiocb->ki_retry = aio_fdsync; |
1515 | break; |
1516 | case IOCB_CMD_FSYNC: |
1517 | ret = -EINVAL; |
1518 | if (file->f_op->aio_fsync) |
1519 | kiocb->ki_retry = aio_fsync; |
1520 | break; |
1521 | default: |
1522 | dprintk("EINVAL: io_submit: no operation provided\n"); |
1523 | ret = -EINVAL; |
1524 | } |
1525 | |
1526 | if (!kiocb->ki_retry) |
1527 | return ret; |
1528 | |
1529 | return 0; |
1530 | } |
1531 | |
1532 | static void aio_batch_add(struct address_space *mapping, |
1533 | struct hlist_head *batch_hash) |
1534 | { |
1535 | struct aio_batch_entry *abe; |
1536 | struct hlist_node *pos; |
1537 | unsigned bucket; |
1538 | |
1539 | bucket = hash_ptr(mapping, AIO_BATCH_HASH_BITS); |
1540 | hlist_for_each_entry(abe, pos, &batch_hash[bucket], list) { |
1541 | if (abe->mapping == mapping) |
1542 | return; |
1543 | } |
1544 | |
1545 | abe = mempool_alloc(abe_pool, GFP_KERNEL); |
1546 | |
1547 | /* |
1548 | * we should be using igrab here, but |
1549 | * we don't want to hammer on the global |
1550 | * inode spinlock just to take an extra |
1551 | * reference on a file that we must already |
1552 | * have a reference to. |
1553 | * |
1554 | * When we're called, we always have a reference |
1555 | * on the file, so we must always have a reference |
1556 | * on the inode, so ihold() is safe here. |
1557 | */ |
1558 | ihold(mapping->host); |
1559 | abe->mapping = mapping; |
1560 | hlist_add_head(&abe->list, &batch_hash[bucket]); |
1561 | return; |
1562 | } |
1563 | |
1564 | static void aio_batch_free(struct hlist_head *batch_hash) |
1565 | { |
1566 | struct aio_batch_entry *abe; |
1567 | struct hlist_node *pos, *n; |
1568 | int i; |
1569 | |
1570 | for (i = 0; i < AIO_BATCH_HASH_SIZE; i++) { |
1571 | hlist_for_each_entry_safe(abe, pos, n, &batch_hash[i], list) { |
1572 | blk_run_address_space(abe->mapping); |
1573 | iput(abe->mapping->host); |
1574 | hlist_del(&abe->list); |
1575 | mempool_free(abe, abe_pool); |
1576 | } |
1577 | } |
1578 | } |
1579 | |
1580 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
1581 | struct iocb *iocb, struct hlist_head *batch_hash, |
1582 | bool compat) |
1583 | { |
1584 | struct kiocb *req; |
1585 | struct file *file; |
1586 | ssize_t ret; |
1587 | |
1588 | /* enforce forwards compatibility on users */ |
1589 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
1590 | pr_debug("EINVAL: io_submit: reserve field set\n"); |
1591 | return -EINVAL; |
1592 | } |
1593 | |
1594 | /* prevent overflows */ |
1595 | if (unlikely( |
1596 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || |
1597 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || |
1598 | ((ssize_t)iocb->aio_nbytes < 0) |
1599 | )) { |
1600 | pr_debug("EINVAL: io_submit: overflow check\n"); |
1601 | return -EINVAL; |
1602 | } |
1603 | |
1604 | file = fget(iocb->aio_fildes); |
1605 | if (unlikely(!file)) |
1606 | return -EBADF; |
1607 | |
1608 | req = aio_get_req(ctx); /* returns with 2 references to req */ |
1609 | if (unlikely(!req)) { |
1610 | fput(file); |
1611 | return -EAGAIN; |
1612 | } |
1613 | req->ki_filp = file; |
1614 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1615 | /* |
1616 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an |
1617 | * instance of the file* now. The file descriptor must be |
1618 | * an eventfd() fd, and will be signaled for each completed |
1619 | * event using the eventfd_signal() function. |
1620 | */ |
1621 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
1622 | if (IS_ERR(req->ki_eventfd)) { |
1623 | ret = PTR_ERR(req->ki_eventfd); |
1624 | req->ki_eventfd = NULL; |
1625 | goto out_put_req; |
1626 | } |
1627 | } |
1628 | |
1629 | ret = put_user(req->ki_key, &user_iocb->aio_key); |
1630 | if (unlikely(ret)) { |
1631 | dprintk("EFAULT: aio_key\n"); |
1632 | goto out_put_req; |
1633 | } |
1634 | |
1635 | req->ki_obj.user = user_iocb; |
1636 | req->ki_user_data = iocb->aio_data; |
1637 | req->ki_pos = iocb->aio_offset; |
1638 | |
1639 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
1640 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
1641 | req->ki_opcode = iocb->aio_lio_opcode; |
1642 | |
1643 | ret = aio_setup_iocb(req, compat); |
1644 | |
1645 | if (ret) |
1646 | goto out_put_req; |
1647 | |
1648 | spin_lock_irq(&ctx->ctx_lock); |
1649 | aio_run_iocb(req); |
1650 | if (!list_empty(&ctx->run_list)) { |
1651 | /* drain the run list */ |
1652 | while (__aio_run_iocbs(ctx)) |
1653 | ; |
1654 | } |
1655 | spin_unlock_irq(&ctx->ctx_lock); |
1656 | if (req->ki_opcode == IOCB_CMD_PREAD || |
1657 | req->ki_opcode == IOCB_CMD_PREADV || |
1658 | req->ki_opcode == IOCB_CMD_PWRITE || |
1659 | req->ki_opcode == IOCB_CMD_PWRITEV) |
1660 | aio_batch_add(file->f_mapping, batch_hash); |
1661 | |
1662 | aio_put_req(req); /* drop extra ref to req */ |
1663 | return 0; |
1664 | |
1665 | out_put_req: |
1666 | aio_put_req(req); /* drop extra ref to req */ |
1667 | aio_put_req(req); /* drop i/o ref to req */ |
1668 | return ret; |
1669 | } |
1670 | |
1671 | long do_io_submit(aio_context_t ctx_id, long nr, |
1672 | struct iocb __user *__user *iocbpp, bool compat) |
1673 | { |
1674 | struct kioctx *ctx; |
1675 | long ret = 0; |
1676 | int i; |
1677 | struct hlist_head batch_hash[AIO_BATCH_HASH_SIZE] = { { 0, }, }; |
1678 | |
1679 | if (unlikely(nr < 0)) |
1680 | return -EINVAL; |
1681 | |
1682 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1683 | nr = LONG_MAX/sizeof(*iocbpp); |
1684 | |
1685 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1686 | return -EFAULT; |
1687 | |
1688 | ctx = lookup_ioctx(ctx_id); |
1689 | if (unlikely(!ctx)) { |
1690 | pr_debug("EINVAL: io_submit: invalid context id\n"); |
1691 | return -EINVAL; |
1692 | } |
1693 | |
1694 | /* |
1695 | * AKPM: should this return a partial result if some of the IOs were |
1696 | * successfully submitted? |
1697 | */ |
1698 | for (i=0; i<nr; i++) { |
1699 | struct iocb __user *user_iocb; |
1700 | struct iocb tmp; |
1701 | |
1702 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
1703 | ret = -EFAULT; |
1704 | break; |
1705 | } |
1706 | |
1707 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
1708 | ret = -EFAULT; |
1709 | break; |
1710 | } |
1711 | |
1712 | ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash, compat); |
1713 | if (ret) |
1714 | break; |
1715 | } |
1716 | aio_batch_free(batch_hash); |
1717 | |
1718 | put_ioctx(ctx); |
1719 | return i ? i : ret; |
1720 | } |
1721 | |
1722 | /* sys_io_submit: |
1723 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns |
1724 | * the number of iocbs queued. May return -EINVAL if the aio_context |
1725 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at |
1726 | * *iocbpp[0] is not properly initialized, if the operation specified |
1727 | * is invalid for the file descriptor in the iocb. May fail with |
1728 | * -EFAULT if any of the data structures point to invalid data. May |
1729 | * fail with -EBADF if the file descriptor specified in the first |
1730 | * iocb is invalid. May fail with -EAGAIN if insufficient resources |
1731 | * are available to queue any iocbs. Will return 0 if nr is 0. Will |
1732 | * fail with -ENOSYS if not implemented. |
1733 | */ |
1734 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, |
1735 | struct iocb __user * __user *, iocbpp) |
1736 | { |
1737 | return do_io_submit(ctx_id, nr, iocbpp, 0); |
1738 | } |
1739 | |
1740 | /* lookup_kiocb |
1741 | * Finds a given iocb for cancellation. |
1742 | */ |
1743 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1744 | u32 key) |
1745 | { |
1746 | struct list_head *pos; |
1747 | |
1748 | assert_spin_locked(&ctx->ctx_lock); |
1749 | |
1750 | /* TODO: use a hash or array, this sucks. */ |
1751 | list_for_each(pos, &ctx->active_reqs) { |
1752 | struct kiocb *kiocb = list_kiocb(pos); |
1753 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
1754 | return kiocb; |
1755 | } |
1756 | return NULL; |
1757 | } |
1758 | |
1759 | /* sys_io_cancel: |
1760 | * Attempts to cancel an iocb previously passed to io_submit. If |
1761 | * the operation is successfully cancelled, the resulting event is |
1762 | * copied into the memory pointed to by result without being placed |
1763 | * into the completion queue and 0 is returned. May fail with |
1764 | * -EFAULT if any of the data structures pointed to are invalid. |
1765 | * May fail with -EINVAL if aio_context specified by ctx_id is |
1766 | * invalid. May fail with -EAGAIN if the iocb specified was not |
1767 | * cancelled. Will fail with -ENOSYS if not implemented. |
1768 | */ |
1769 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1770 | struct io_event __user *, result) |
1771 | { |
1772 | int (*cancel)(struct kiocb *iocb, struct io_event *res); |
1773 | struct kioctx *ctx; |
1774 | struct kiocb *kiocb; |
1775 | u32 key; |
1776 | int ret; |
1777 | |
1778 | ret = get_user(key, &iocb->aio_key); |
1779 | if (unlikely(ret)) |
1780 | return -EFAULT; |
1781 | |
1782 | ctx = lookup_ioctx(ctx_id); |
1783 | if (unlikely(!ctx)) |
1784 | return -EINVAL; |
1785 | |
1786 | spin_lock_irq(&ctx->ctx_lock); |
1787 | ret = -EAGAIN; |
1788 | kiocb = lookup_kiocb(ctx, iocb, key); |
1789 | if (kiocb && kiocb->ki_cancel) { |
1790 | cancel = kiocb->ki_cancel; |
1791 | kiocb->ki_users ++; |
1792 | kiocbSetCancelled(kiocb); |
1793 | } else |
1794 | cancel = NULL; |
1795 | spin_unlock_irq(&ctx->ctx_lock); |
1796 | |
1797 | if (NULL != cancel) { |
1798 | struct io_event tmp; |
1799 | pr_debug("calling cancel\n"); |
1800 | memset(&tmp, 0, sizeof(tmp)); |
1801 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
1802 | tmp.data = kiocb->ki_user_data; |
1803 | ret = cancel(kiocb, &tmp); |
1804 | if (!ret) { |
1805 | /* Cancellation succeeded -- copy the result |
1806 | * into the user's buffer. |
1807 | */ |
1808 | if (copy_to_user(result, &tmp, sizeof(tmp))) |
1809 | ret = -EFAULT; |
1810 | } |
1811 | } else |
1812 | ret = -EINVAL; |
1813 | |
1814 | put_ioctx(ctx); |
1815 | |
1816 | return ret; |
1817 | } |
1818 | |
1819 | /* io_getevents: |
1820 | * Attempts to read at least min_nr events and up to nr events from |
1821 | * the completion queue for the aio_context specified by ctx_id. If |
1822 | * it succeeds, the number of read events is returned. May fail with |
1823 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is |
1824 | * out of range, if timeout is out of range. May fail with -EFAULT |
1825 | * if any of the memory specified is invalid. May return 0 or |
1826 | * < min_nr if the timeout specified by timeout has elapsed |
1827 | * before sufficient events are available, where timeout == NULL |
1828 | * specifies an infinite timeout. Note that the timeout pointed to by |
1829 | * timeout is relative and will be updated if not NULL and the |
1830 | * operation blocks. Will fail with -ENOSYS if not implemented. |
1831 | */ |
1832 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1833 | long, min_nr, |
1834 | long, nr, |
1835 | struct io_event __user *, events, |
1836 | struct timespec __user *, timeout) |
1837 | { |
1838 | struct kioctx *ioctx = lookup_ioctx(ctx_id); |
1839 | long ret = -EINVAL; |
1840 | |
1841 | if (likely(ioctx)) { |
1842 | if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0)) |
1843 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
1844 | put_ioctx(ioctx); |
1845 | } |
1846 | |
1847 | asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); |
1848 | return ret; |
1849 | } |
1850 |
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Tags:
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od-2011-09-18
v2.6.34-rc5
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