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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/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 | /* Used for rare fput completion. */ |
60 | static void aio_fput_routine(struct work_struct *); |
61 | static DECLARE_WORK(fput_work, aio_fput_routine); |
62 | |
63 | static DEFINE_SPINLOCK(fput_lock); |
64 | static LIST_HEAD(fput_head); |
65 | |
66 | static void aio_kick_handler(struct work_struct *); |
67 | static void aio_queue_work(struct kioctx *); |
68 | |
69 | /* aio_setup |
70 | * Creates the slab caches used by the aio routines, panic on |
71 | * failure as this is done early during the boot sequence. |
72 | */ |
73 | static int __init aio_setup(void) |
74 | { |
75 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
76 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
77 | |
78 | aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */ |
79 | BUG_ON(!aio_wq); |
80 | |
81 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); |
82 | |
83 | return 0; |
84 | } |
85 | __initcall(aio_setup); |
86 | |
87 | static void aio_free_ring(struct kioctx *ctx) |
88 | { |
89 | struct aio_ring_info *info = &ctx->ring_info; |
90 | long i; |
91 | |
92 | for (i=0; i<info->nr_pages; i++) |
93 | put_page(info->ring_pages[i]); |
94 | |
95 | if (info->mmap_size) { |
96 | down_write(&ctx->mm->mmap_sem); |
97 | do_munmap(ctx->mm, info->mmap_base, info->mmap_size); |
98 | up_write(&ctx->mm->mmap_sem); |
99 | } |
100 | |
101 | if (info->ring_pages && info->ring_pages != info->internal_pages) |
102 | kfree(info->ring_pages); |
103 | info->ring_pages = NULL; |
104 | info->nr = 0; |
105 | } |
106 | |
107 | static int aio_setup_ring(struct kioctx *ctx) |
108 | { |
109 | struct aio_ring *ring; |
110 | struct aio_ring_info *info = &ctx->ring_info; |
111 | unsigned nr_events = ctx->max_reqs; |
112 | unsigned long size; |
113 | int nr_pages; |
114 | |
115 | /* Compensate for the ring buffer's head/tail overlap entry */ |
116 | nr_events += 2; /* 1 is required, 2 for good luck */ |
117 | |
118 | size = sizeof(struct aio_ring); |
119 | size += sizeof(struct io_event) * nr_events; |
120 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; |
121 | |
122 | if (nr_pages < 0) |
123 | return -EINVAL; |
124 | |
125 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); |
126 | |
127 | info->nr = 0; |
128 | info->ring_pages = info->internal_pages; |
129 | if (nr_pages > AIO_RING_PAGES) { |
130 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); |
131 | if (!info->ring_pages) |
132 | return -ENOMEM; |
133 | } |
134 | |
135 | info->mmap_size = nr_pages * PAGE_SIZE; |
136 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); |
137 | down_write(&ctx->mm->mmap_sem); |
138 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, |
139 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, |
140 | 0); |
141 | if (IS_ERR((void *)info->mmap_base)) { |
142 | up_write(&ctx->mm->mmap_sem); |
143 | info->mmap_size = 0; |
144 | aio_free_ring(ctx); |
145 | return -EAGAIN; |
146 | } |
147 | |
148 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); |
149 | info->nr_pages = get_user_pages(current, ctx->mm, |
150 | info->mmap_base, nr_pages, |
151 | 1, 0, info->ring_pages, NULL); |
152 | up_write(&ctx->mm->mmap_sem); |
153 | |
154 | if (unlikely(info->nr_pages != nr_pages)) { |
155 | aio_free_ring(ctx); |
156 | return -EAGAIN; |
157 | } |
158 | |
159 | ctx->user_id = info->mmap_base; |
160 | |
161 | info->nr = nr_events; /* trusted copy */ |
162 | |
163 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
164 | ring->nr = nr_events; /* user copy */ |
165 | ring->id = ctx->user_id; |
166 | ring->head = ring->tail = 0; |
167 | ring->magic = AIO_RING_MAGIC; |
168 | ring->compat_features = AIO_RING_COMPAT_FEATURES; |
169 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; |
170 | ring->header_length = sizeof(struct aio_ring); |
171 | kunmap_atomic(ring, KM_USER0); |
172 | |
173 | return 0; |
174 | } |
175 | |
176 | |
177 | /* aio_ring_event: returns a pointer to the event at the given index from |
178 | * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); |
179 | */ |
180 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
181 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) |
182 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) |
183 | |
184 | #define aio_ring_event(info, nr, km) ({ \ |
185 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ |
186 | struct io_event *__event; \ |
187 | __event = kmap_atomic( \ |
188 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ |
189 | __event += pos % AIO_EVENTS_PER_PAGE; \ |
190 | __event; \ |
191 | }) |
192 | |
193 | #define put_aio_ring_event(event, km) do { \ |
194 | struct io_event *__event = (event); \ |
195 | (void)__event; \ |
196 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ |
197 | } while(0) |
198 | |
199 | static void ctx_rcu_free(struct rcu_head *head) |
200 | { |
201 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); |
202 | unsigned nr_events = ctx->max_reqs; |
203 | |
204 | kmem_cache_free(kioctx_cachep, ctx); |
205 | |
206 | if (nr_events) { |
207 | spin_lock(&aio_nr_lock); |
208 | BUG_ON(aio_nr - nr_events > aio_nr); |
209 | aio_nr -= nr_events; |
210 | spin_unlock(&aio_nr_lock); |
211 | } |
212 | } |
213 | |
214 | /* __put_ioctx |
215 | * Called when the last user of an aio context has gone away, |
216 | * and the struct needs to be freed. |
217 | */ |
218 | static void __put_ioctx(struct kioctx *ctx) |
219 | { |
220 | BUG_ON(ctx->reqs_active); |
221 | |
222 | cancel_delayed_work(&ctx->wq); |
223 | cancel_work_sync(&ctx->wq.work); |
224 | aio_free_ring(ctx); |
225 | mmdrop(ctx->mm); |
226 | ctx->mm = NULL; |
227 | pr_debug("__put_ioctx: freeing %p\n", ctx); |
228 | call_rcu(&ctx->rcu_head, ctx_rcu_free); |
229 | } |
230 | |
231 | static inline void get_ioctx(struct kioctx *kioctx) |
232 | { |
233 | BUG_ON(atomic_read(&kioctx->users) <= 0); |
234 | atomic_inc(&kioctx->users); |
235 | } |
236 | |
237 | static inline int try_get_ioctx(struct kioctx *kioctx) |
238 | { |
239 | return atomic_inc_not_zero(&kioctx->users); |
240 | } |
241 | |
242 | static inline void put_ioctx(struct kioctx *kioctx) |
243 | { |
244 | BUG_ON(atomic_read(&kioctx->users) <= 0); |
245 | if (unlikely(atomic_dec_and_test(&kioctx->users))) |
246 | __put_ioctx(kioctx); |
247 | } |
248 | |
249 | /* ioctx_alloc |
250 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
251 | */ |
252 | static struct kioctx *ioctx_alloc(unsigned nr_events) |
253 | { |
254 | struct mm_struct *mm; |
255 | struct kioctx *ctx; |
256 | int did_sync = 0; |
257 | |
258 | /* Prevent overflows */ |
259 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || |
260 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { |
261 | pr_debug("ENOMEM: nr_events too high\n"); |
262 | return ERR_PTR(-EINVAL); |
263 | } |
264 | |
265 | if ((unsigned long)nr_events > aio_max_nr) |
266 | return ERR_PTR(-EAGAIN); |
267 | |
268 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
269 | if (!ctx) |
270 | return ERR_PTR(-ENOMEM); |
271 | |
272 | ctx->max_reqs = nr_events; |
273 | mm = ctx->mm = current->mm; |
274 | atomic_inc(&mm->mm_count); |
275 | |
276 | atomic_set(&ctx->users, 1); |
277 | spin_lock_init(&ctx->ctx_lock); |
278 | spin_lock_init(&ctx->ring_info.ring_lock); |
279 | init_waitqueue_head(&ctx->wait); |
280 | |
281 | INIT_LIST_HEAD(&ctx->active_reqs); |
282 | INIT_LIST_HEAD(&ctx->run_list); |
283 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); |
284 | |
285 | if (aio_setup_ring(ctx) < 0) |
286 | goto out_freectx; |
287 | |
288 | /* limit the number of system wide aios */ |
289 | do { |
290 | spin_lock_bh(&aio_nr_lock); |
291 | if (aio_nr + nr_events > aio_max_nr || |
292 | aio_nr + nr_events < aio_nr) |
293 | ctx->max_reqs = 0; |
294 | else |
295 | aio_nr += ctx->max_reqs; |
296 | spin_unlock_bh(&aio_nr_lock); |
297 | if (ctx->max_reqs || did_sync) |
298 | break; |
299 | |
300 | /* wait for rcu callbacks to have completed before giving up */ |
301 | synchronize_rcu(); |
302 | did_sync = 1; |
303 | ctx->max_reqs = nr_events; |
304 | } while (1); |
305 | |
306 | if (ctx->max_reqs == 0) |
307 | goto out_cleanup; |
308 | |
309 | /* now link into global list. */ |
310 | spin_lock(&mm->ioctx_lock); |
311 | hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); |
312 | spin_unlock(&mm->ioctx_lock); |
313 | |
314 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
315 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); |
316 | return ctx; |
317 | |
318 | out_cleanup: |
319 | __put_ioctx(ctx); |
320 | return ERR_PTR(-EAGAIN); |
321 | |
322 | out_freectx: |
323 | mmdrop(mm); |
324 | kmem_cache_free(kioctx_cachep, ctx); |
325 | ctx = ERR_PTR(-ENOMEM); |
326 | |
327 | dprintk("aio: error allocating ioctx %p\n", ctx); |
328 | return ctx; |
329 | } |
330 | |
331 | /* aio_cancel_all |
332 | * Cancels all outstanding aio requests on an aio context. Used |
333 | * when the processes owning a context have all exited to encourage |
334 | * the rapid destruction of the kioctx. |
335 | */ |
336 | static void aio_cancel_all(struct kioctx *ctx) |
337 | { |
338 | int (*cancel)(struct kiocb *, struct io_event *); |
339 | struct io_event res; |
340 | spin_lock_irq(&ctx->ctx_lock); |
341 | ctx->dead = 1; |
342 | while (!list_empty(&ctx->active_reqs)) { |
343 | struct list_head *pos = ctx->active_reqs.next; |
344 | struct kiocb *iocb = list_kiocb(pos); |
345 | list_del_init(&iocb->ki_list); |
346 | cancel = iocb->ki_cancel; |
347 | kiocbSetCancelled(iocb); |
348 | if (cancel) { |
349 | iocb->ki_users++; |
350 | spin_unlock_irq(&ctx->ctx_lock); |
351 | cancel(iocb, &res); |
352 | spin_lock_irq(&ctx->ctx_lock); |
353 | } |
354 | } |
355 | spin_unlock_irq(&ctx->ctx_lock); |
356 | } |
357 | |
358 | static void wait_for_all_aios(struct kioctx *ctx) |
359 | { |
360 | struct task_struct *tsk = current; |
361 | DECLARE_WAITQUEUE(wait, tsk); |
362 | |
363 | spin_lock_irq(&ctx->ctx_lock); |
364 | if (!ctx->reqs_active) |
365 | goto out; |
366 | |
367 | add_wait_queue(&ctx->wait, &wait); |
368 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
369 | while (ctx->reqs_active) { |
370 | spin_unlock_irq(&ctx->ctx_lock); |
371 | io_schedule(); |
372 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
373 | spin_lock_irq(&ctx->ctx_lock); |
374 | } |
375 | __set_task_state(tsk, TASK_RUNNING); |
376 | remove_wait_queue(&ctx->wait, &wait); |
377 | |
378 | out: |
379 | spin_unlock_irq(&ctx->ctx_lock); |
380 | } |
381 | |
382 | /* wait_on_sync_kiocb: |
383 | * Waits on the given sync kiocb to complete. |
384 | */ |
385 | ssize_t wait_on_sync_kiocb(struct kiocb *iocb) |
386 | { |
387 | while (iocb->ki_users) { |
388 | set_current_state(TASK_UNINTERRUPTIBLE); |
389 | if (!iocb->ki_users) |
390 | break; |
391 | io_schedule(); |
392 | } |
393 | __set_current_state(TASK_RUNNING); |
394 | return iocb->ki_user_data; |
395 | } |
396 | EXPORT_SYMBOL(wait_on_sync_kiocb); |
397 | |
398 | /* exit_aio: called when the last user of mm goes away. At this point, |
399 | * there is no way for any new requests to be submited or any of the |
400 | * io_* syscalls to be called on the context. However, there may be |
401 | * outstanding requests which hold references to the context; as they |
402 | * go away, they will call put_ioctx and release any pinned memory |
403 | * associated with the request (held via struct page * references). |
404 | */ |
405 | void exit_aio(struct mm_struct *mm) |
406 | { |
407 | struct kioctx *ctx; |
408 | |
409 | while (!hlist_empty(&mm->ioctx_list)) { |
410 | ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); |
411 | hlist_del_rcu(&ctx->list); |
412 | |
413 | aio_cancel_all(ctx); |
414 | |
415 | wait_for_all_aios(ctx); |
416 | /* |
417 | * Ensure we don't leave the ctx on the aio_wq |
418 | */ |
419 | cancel_work_sync(&ctx->wq.work); |
420 | |
421 | if (1 != atomic_read(&ctx->users)) |
422 | printk(KERN_DEBUG |
423 | "exit_aio:ioctx still alive: %d %d %d\n", |
424 | atomic_read(&ctx->users), ctx->dead, |
425 | ctx->reqs_active); |
426 | put_ioctx(ctx); |
427 | } |
428 | } |
429 | |
430 | /* aio_get_req |
431 | * Allocate a slot for an aio request. Increments the users count |
432 | * of the kioctx so that the kioctx stays around until all requests are |
433 | * complete. Returns NULL if no requests are free. |
434 | * |
435 | * Returns with kiocb->users set to 2. The io submit code path holds |
436 | * an extra reference while submitting the i/o. |
437 | * This prevents races between the aio code path referencing the |
438 | * req (after submitting it) and aio_complete() freeing the req. |
439 | */ |
440 | static struct kiocb *__aio_get_req(struct kioctx *ctx) |
441 | { |
442 | struct kiocb *req = NULL; |
443 | |
444 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
445 | if (unlikely(!req)) |
446 | return NULL; |
447 | |
448 | req->ki_flags = 0; |
449 | req->ki_users = 2; |
450 | req->ki_key = 0; |
451 | req->ki_ctx = ctx; |
452 | req->ki_cancel = NULL; |
453 | req->ki_retry = NULL; |
454 | req->ki_dtor = NULL; |
455 | req->private = NULL; |
456 | req->ki_iovec = NULL; |
457 | INIT_LIST_HEAD(&req->ki_run_list); |
458 | req->ki_eventfd = NULL; |
459 | |
460 | return req; |
461 | } |
462 | |
463 | /* |
464 | * struct kiocb's are allocated in batches to reduce the number of |
465 | * times the ctx lock is acquired and released. |
466 | */ |
467 | #define KIOCB_BATCH_SIZE 32L |
468 | struct kiocb_batch { |
469 | struct list_head head; |
470 | long count; /* number of requests left to allocate */ |
471 | }; |
472 | |
473 | static void kiocb_batch_init(struct kiocb_batch *batch, long total) |
474 | { |
475 | INIT_LIST_HEAD(&batch->head); |
476 | batch->count = total; |
477 | } |
478 | |
479 | static void kiocb_batch_free(struct kiocb_batch *batch) |
480 | { |
481 | struct kiocb *req, *n; |
482 | |
483 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
484 | list_del(&req->ki_batch); |
485 | kmem_cache_free(kiocb_cachep, req); |
486 | } |
487 | } |
488 | |
489 | /* |
490 | * Allocate a batch of kiocbs. This avoids taking and dropping the |
491 | * context lock a lot during setup. |
492 | */ |
493 | static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) |
494 | { |
495 | unsigned short allocated, to_alloc; |
496 | long avail; |
497 | bool called_fput = false; |
498 | struct kiocb *req, *n; |
499 | struct aio_ring *ring; |
500 | |
501 | to_alloc = min(batch->count, KIOCB_BATCH_SIZE); |
502 | for (allocated = 0; allocated < to_alloc; allocated++) { |
503 | req = __aio_get_req(ctx); |
504 | if (!req) |
505 | /* allocation failed, go with what we've got */ |
506 | break; |
507 | list_add(&req->ki_batch, &batch->head); |
508 | } |
509 | |
510 | if (allocated == 0) |
511 | goto out; |
512 | |
513 | retry: |
514 | spin_lock_irq(&ctx->ctx_lock); |
515 | ring = kmap_atomic(ctx->ring_info.ring_pages[0]); |
516 | |
517 | avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active; |
518 | BUG_ON(avail < 0); |
519 | if (avail == 0 && !called_fput) { |
520 | /* |
521 | * Handle a potential starvation case. It is possible that |
522 | * we hold the last reference on a struct file, causing us |
523 | * to delay the final fput to non-irq context. In this case, |
524 | * ctx->reqs_active is artificially high. Calling the fput |
525 | * routine here may free up a slot in the event completion |
526 | * ring, allowing this allocation to succeed. |
527 | */ |
528 | kunmap_atomic(ring); |
529 | spin_unlock_irq(&ctx->ctx_lock); |
530 | aio_fput_routine(NULL); |
531 | called_fput = true; |
532 | goto retry; |
533 | } |
534 | |
535 | if (avail < allocated) { |
536 | /* Trim back the number of requests. */ |
537 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { |
538 | list_del(&req->ki_batch); |
539 | kmem_cache_free(kiocb_cachep, req); |
540 | if (--allocated <= avail) |
541 | break; |
542 | } |
543 | } |
544 | |
545 | batch->count -= allocated; |
546 | list_for_each_entry(req, &batch->head, ki_batch) { |
547 | list_add(&req->ki_list, &ctx->active_reqs); |
548 | ctx->reqs_active++; |
549 | } |
550 | |
551 | kunmap_atomic(ring); |
552 | spin_unlock_irq(&ctx->ctx_lock); |
553 | |
554 | out: |
555 | return allocated; |
556 | } |
557 | |
558 | static inline struct kiocb *aio_get_req(struct kioctx *ctx, |
559 | struct kiocb_batch *batch) |
560 | { |
561 | struct kiocb *req; |
562 | |
563 | if (list_empty(&batch->head)) |
564 | if (kiocb_batch_refill(ctx, batch) == 0) |
565 | return NULL; |
566 | req = list_first_entry(&batch->head, struct kiocb, ki_batch); |
567 | list_del(&req->ki_batch); |
568 | return req; |
569 | } |
570 | |
571 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) |
572 | { |
573 | assert_spin_locked(&ctx->ctx_lock); |
574 | |
575 | if (req->ki_eventfd != NULL) |
576 | eventfd_ctx_put(req->ki_eventfd); |
577 | if (req->ki_dtor) |
578 | req->ki_dtor(req); |
579 | if (req->ki_iovec != &req->ki_inline_vec) |
580 | kfree(req->ki_iovec); |
581 | kmem_cache_free(kiocb_cachep, req); |
582 | ctx->reqs_active--; |
583 | |
584 | if (unlikely(!ctx->reqs_active && ctx->dead)) |
585 | wake_up_all(&ctx->wait); |
586 | } |
587 | |
588 | static void aio_fput_routine(struct work_struct *data) |
589 | { |
590 | spin_lock_irq(&fput_lock); |
591 | while (likely(!list_empty(&fput_head))) { |
592 | struct kiocb *req = list_kiocb(fput_head.next); |
593 | struct kioctx *ctx = req->ki_ctx; |
594 | |
595 | list_del(&req->ki_list); |
596 | spin_unlock_irq(&fput_lock); |
597 | |
598 | /* Complete the fput(s) */ |
599 | if (req->ki_filp != NULL) |
600 | fput(req->ki_filp); |
601 | |
602 | /* Link the iocb into the context's free list */ |
603 | spin_lock_irq(&ctx->ctx_lock); |
604 | really_put_req(ctx, req); |
605 | spin_unlock_irq(&ctx->ctx_lock); |
606 | |
607 | put_ioctx(ctx); |
608 | spin_lock_irq(&fput_lock); |
609 | } |
610 | spin_unlock_irq(&fput_lock); |
611 | } |
612 | |
613 | /* __aio_put_req |
614 | * Returns true if this put was the last user of the request. |
615 | */ |
616 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) |
617 | { |
618 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", |
619 | req, atomic_long_read(&req->ki_filp->f_count)); |
620 | |
621 | assert_spin_locked(&ctx->ctx_lock); |
622 | |
623 | req->ki_users--; |
624 | BUG_ON(req->ki_users < 0); |
625 | if (likely(req->ki_users)) |
626 | return 0; |
627 | list_del(&req->ki_list); /* remove from active_reqs */ |
628 | req->ki_cancel = NULL; |
629 | req->ki_retry = NULL; |
630 | |
631 | /* |
632 | * Try to optimize the aio and eventfd file* puts, by avoiding to |
633 | * schedule work in case it is not final fput() time. In normal cases, |
634 | * we would not be holding the last reference to the file*, so |
635 | * this function will be executed w/out any aio kthread wakeup. |
636 | */ |
637 | if (unlikely(!fput_atomic(req->ki_filp))) { |
638 | get_ioctx(ctx); |
639 | spin_lock(&fput_lock); |
640 | list_add(&req->ki_list, &fput_head); |
641 | spin_unlock(&fput_lock); |
642 | schedule_work(&fput_work); |
643 | } else { |
644 | req->ki_filp = NULL; |
645 | really_put_req(ctx, req); |
646 | } |
647 | return 1; |
648 | } |
649 | |
650 | /* aio_put_req |
651 | * Returns true if this put was the last user of the kiocb, |
652 | * false if the request is still in use. |
653 | */ |
654 | int aio_put_req(struct kiocb *req) |
655 | { |
656 | struct kioctx *ctx = req->ki_ctx; |
657 | int ret; |
658 | spin_lock_irq(&ctx->ctx_lock); |
659 | ret = __aio_put_req(ctx, req); |
660 | spin_unlock_irq(&ctx->ctx_lock); |
661 | return ret; |
662 | } |
663 | EXPORT_SYMBOL(aio_put_req); |
664 | |
665 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
666 | { |
667 | struct mm_struct *mm = current->mm; |
668 | struct kioctx *ctx, *ret = NULL; |
669 | struct hlist_node *n; |
670 | |
671 | rcu_read_lock(); |
672 | |
673 | hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { |
674 | /* |
675 | * RCU protects us against accessing freed memory but |
676 | * we have to be careful not to get a reference when the |
677 | * reference count already dropped to 0 (ctx->dead test |
678 | * is unreliable because of races). |
679 | */ |
680 | if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){ |
681 | ret = ctx; |
682 | break; |
683 | } |
684 | } |
685 | |
686 | rcu_read_unlock(); |
687 | return ret; |
688 | } |
689 | |
690 | /* |
691 | * Queue up a kiocb to be retried. Assumes that the kiocb |
692 | * has already been marked as kicked, and places it on |
693 | * the retry run list for the corresponding ioctx, if it |
694 | * isn't already queued. Returns 1 if it actually queued |
695 | * the kiocb (to tell the caller to activate the work |
696 | * queue to process it), or 0, if it found that it was |
697 | * already queued. |
698 | */ |
699 | static inline int __queue_kicked_iocb(struct kiocb *iocb) |
700 | { |
701 | struct kioctx *ctx = iocb->ki_ctx; |
702 | |
703 | assert_spin_locked(&ctx->ctx_lock); |
704 | |
705 | if (list_empty(&iocb->ki_run_list)) { |
706 | list_add_tail(&iocb->ki_run_list, |
707 | &ctx->run_list); |
708 | return 1; |
709 | } |
710 | return 0; |
711 | } |
712 | |
713 | /* aio_run_iocb |
714 | * This is the core aio execution routine. It is |
715 | * invoked both for initial i/o submission and |
716 | * subsequent retries via the aio_kick_handler. |
717 | * Expects to be invoked with iocb->ki_ctx->lock |
718 | * already held. The lock is released and reacquired |
719 | * as needed during processing. |
720 | * |
721 | * Calls the iocb retry method (already setup for the |
722 | * iocb on initial submission) for operation specific |
723 | * handling, but takes care of most of common retry |
724 | * execution details for a given iocb. The retry method |
725 | * needs to be non-blocking as far as possible, to avoid |
726 | * holding up other iocbs waiting to be serviced by the |
727 | * retry kernel thread. |
728 | * |
729 | * The trickier parts in this code have to do with |
730 | * ensuring that only one retry instance is in progress |
731 | * for a given iocb at any time. Providing that guarantee |
732 | * simplifies the coding of individual aio operations as |
733 | * it avoids various potential races. |
734 | */ |
735 | static ssize_t aio_run_iocb(struct kiocb *iocb) |
736 | { |
737 | struct kioctx *ctx = iocb->ki_ctx; |
738 | ssize_t (*retry)(struct kiocb *); |
739 | ssize_t ret; |
740 | |
741 | if (!(retry = iocb->ki_retry)) { |
742 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); |
743 | return 0; |
744 | } |
745 | |
746 | /* |
747 | * We don't want the next retry iteration for this |
748 | * operation to start until this one has returned and |
749 | * updated the iocb state. However, wait_queue functions |
750 | * can trigger a kick_iocb from interrupt context in the |
751 | * meantime, indicating that data is available for the next |
752 | * iteration. We want to remember that and enable the |
753 | * next retry iteration _after_ we are through with |
754 | * this one. |
755 | * |
756 | * So, in order to be able to register a "kick", but |
757 | * prevent it from being queued now, we clear the kick |
758 | * flag, but make the kick code *think* that the iocb is |
759 | * still on the run list until we are actually done. |
760 | * When we are done with this iteration, we check if |
761 | * the iocb was kicked in the meantime and if so, queue |
762 | * it up afresh. |
763 | */ |
764 | |
765 | kiocbClearKicked(iocb); |
766 | |
767 | /* |
768 | * This is so that aio_complete knows it doesn't need to |
769 | * pull the iocb off the run list (We can't just call |
770 | * INIT_LIST_HEAD because we don't want a kick_iocb to |
771 | * queue this on the run list yet) |
772 | */ |
773 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; |
774 | spin_unlock_irq(&ctx->ctx_lock); |
775 | |
776 | /* Quit retrying if the i/o has been cancelled */ |
777 | if (kiocbIsCancelled(iocb)) { |
778 | ret = -EINTR; |
779 | aio_complete(iocb, ret, 0); |
780 | /* must not access the iocb after this */ |
781 | goto out; |
782 | } |
783 | |
784 | /* |
785 | * Now we are all set to call the retry method in async |
786 | * context. |
787 | */ |
788 | ret = retry(iocb); |
789 | |
790 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { |
791 | /* |
792 | * There's no easy way to restart the syscall since other AIO's |
793 | * may be already running. Just fail this IO with EINTR. |
794 | */ |
795 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || |
796 | ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK)) |
797 | ret = -EINTR; |
798 | aio_complete(iocb, ret, 0); |
799 | } |
800 | out: |
801 | spin_lock_irq(&ctx->ctx_lock); |
802 | |
803 | if (-EIOCBRETRY == ret) { |
804 | /* |
805 | * OK, now that we are done with this iteration |
806 | * and know that there is more left to go, |
807 | * this is where we let go so that a subsequent |
808 | * "kick" can start the next iteration |
809 | */ |
810 | |
811 | /* will make __queue_kicked_iocb succeed from here on */ |
812 | INIT_LIST_HEAD(&iocb->ki_run_list); |
813 | /* we must queue the next iteration ourselves, if it |
814 | * has already been kicked */ |
815 | if (kiocbIsKicked(iocb)) { |
816 | __queue_kicked_iocb(iocb); |
817 | |
818 | /* |
819 | * __queue_kicked_iocb will always return 1 here, because |
820 | * iocb->ki_run_list is empty at this point so it should |
821 | * be safe to unconditionally queue the context into the |
822 | * work queue. |
823 | */ |
824 | aio_queue_work(ctx); |
825 | } |
826 | } |
827 | return ret; |
828 | } |
829 | |
830 | /* |
831 | * __aio_run_iocbs: |
832 | * Process all pending retries queued on the ioctx |
833 | * run list. |
834 | * Assumes it is operating within the aio issuer's mm |
835 | * context. |
836 | */ |
837 | static int __aio_run_iocbs(struct kioctx *ctx) |
838 | { |
839 | struct kiocb *iocb; |
840 | struct list_head run_list; |
841 | |
842 | assert_spin_locked(&ctx->ctx_lock); |
843 | |
844 | list_replace_init(&ctx->run_list, &run_list); |
845 | while (!list_empty(&run_list)) { |
846 | iocb = list_entry(run_list.next, struct kiocb, |
847 | ki_run_list); |
848 | list_del(&iocb->ki_run_list); |
849 | /* |
850 | * Hold an extra reference while retrying i/o. |
851 | */ |
852 | iocb->ki_users++; /* grab extra reference */ |
853 | aio_run_iocb(iocb); |
854 | __aio_put_req(ctx, iocb); |
855 | } |
856 | if (!list_empty(&ctx->run_list)) |
857 | return 1; |
858 | return 0; |
859 | } |
860 | |
861 | static void aio_queue_work(struct kioctx * ctx) |
862 | { |
863 | unsigned long timeout; |
864 | /* |
865 | * if someone is waiting, get the work started right |
866 | * away, otherwise, use a longer delay |
867 | */ |
868 | smp_mb(); |
869 | if (waitqueue_active(&ctx->wait)) |
870 | timeout = 1; |
871 | else |
872 | timeout = HZ/10; |
873 | queue_delayed_work(aio_wq, &ctx->wq, timeout); |
874 | } |
875 | |
876 | /* |
877 | * aio_run_all_iocbs: |
878 | * Process all pending retries queued on the ioctx |
879 | * run list, and keep running them until the list |
880 | * stays empty. |
881 | * Assumes it is operating within the aio issuer's mm context. |
882 | */ |
883 | static inline void aio_run_all_iocbs(struct kioctx *ctx) |
884 | { |
885 | spin_lock_irq(&ctx->ctx_lock); |
886 | while (__aio_run_iocbs(ctx)) |
887 | ; |
888 | spin_unlock_irq(&ctx->ctx_lock); |
889 | } |
890 | |
891 | /* |
892 | * aio_kick_handler: |
893 | * Work queue handler triggered to process pending |
894 | * retries on an ioctx. Takes on the aio issuer's |
895 | * mm context before running the iocbs, so that |
896 | * copy_xxx_user operates on the issuer's address |
897 | * space. |
898 | * Run on aiod's context. |
899 | */ |
900 | static void aio_kick_handler(struct work_struct *work) |
901 | { |
902 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); |
903 | mm_segment_t oldfs = get_fs(); |
904 | struct mm_struct *mm; |
905 | int requeue; |
906 | |
907 | set_fs(USER_DS); |
908 | use_mm(ctx->mm); |
909 | spin_lock_irq(&ctx->ctx_lock); |
910 | requeue =__aio_run_iocbs(ctx); |
911 | mm = ctx->mm; |
912 | spin_unlock_irq(&ctx->ctx_lock); |
913 | unuse_mm(mm); |
914 | set_fs(oldfs); |
915 | /* |
916 | * we're in a worker thread already, don't use queue_delayed_work, |
917 | */ |
918 | if (requeue) |
919 | queue_delayed_work(aio_wq, &ctx->wq, 0); |
920 | } |
921 | |
922 | |
923 | /* |
924 | * Called by kick_iocb to queue the kiocb for retry |
925 | * and if required activate the aio work queue to process |
926 | * it |
927 | */ |
928 | static void try_queue_kicked_iocb(struct kiocb *iocb) |
929 | { |
930 | struct kioctx *ctx = iocb->ki_ctx; |
931 | unsigned long flags; |
932 | int run = 0; |
933 | |
934 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
935 | /* set this inside the lock so that we can't race with aio_run_iocb() |
936 | * testing it and putting the iocb on the run list under the lock */ |
937 | if (!kiocbTryKick(iocb)) |
938 | run = __queue_kicked_iocb(iocb); |
939 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
940 | if (run) |
941 | aio_queue_work(ctx); |
942 | } |
943 | |
944 | /* |
945 | * kick_iocb: |
946 | * Called typically from a wait queue callback context |
947 | * to trigger a retry of the iocb. |
948 | * The retry is usually executed by aio workqueue |
949 | * threads (See aio_kick_handler). |
950 | */ |
951 | void kick_iocb(struct kiocb *iocb) |
952 | { |
953 | /* sync iocbs are easy: they can only ever be executing from a |
954 | * single context. */ |
955 | if (is_sync_kiocb(iocb)) { |
956 | kiocbSetKicked(iocb); |
957 | wake_up_process(iocb->ki_obj.tsk); |
958 | return; |
959 | } |
960 | |
961 | try_queue_kicked_iocb(iocb); |
962 | } |
963 | EXPORT_SYMBOL(kick_iocb); |
964 | |
965 | /* aio_complete |
966 | * Called when the io request on the given iocb is complete. |
967 | * Returns true if this is the last user of the request. The |
968 | * only other user of the request can be the cancellation code. |
969 | */ |
970 | int aio_complete(struct kiocb *iocb, long res, long res2) |
971 | { |
972 | struct kioctx *ctx = iocb->ki_ctx; |
973 | struct aio_ring_info *info; |
974 | struct aio_ring *ring; |
975 | struct io_event *event; |
976 | unsigned long flags; |
977 | unsigned long tail; |
978 | int ret; |
979 | |
980 | /* |
981 | * Special case handling for sync iocbs: |
982 | * - events go directly into the iocb for fast handling |
983 | * - the sync task with the iocb in its stack holds the single iocb |
984 | * ref, no other paths have a way to get another ref |
985 | * - the sync task helpfully left a reference to itself in the iocb |
986 | */ |
987 | if (is_sync_kiocb(iocb)) { |
988 | BUG_ON(iocb->ki_users != 1); |
989 | iocb->ki_user_data = res; |
990 | iocb->ki_users = 0; |
991 | wake_up_process(iocb->ki_obj.tsk); |
992 | return 1; |
993 | } |
994 | |
995 | info = &ctx->ring_info; |
996 | |
997 | /* add a completion event to the ring buffer. |
998 | * must be done holding ctx->ctx_lock to prevent |
999 | * other code from messing with the tail |
1000 | * pointer since we might be called from irq |
1001 | * context. |
1002 | */ |
1003 | spin_lock_irqsave(&ctx->ctx_lock, flags); |
1004 | |
1005 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) |
1006 | list_del_init(&iocb->ki_run_list); |
1007 | |
1008 | /* |
1009 | * cancelled requests don't get events, userland was given one |
1010 | * when the event got cancelled. |
1011 | */ |
1012 | if (kiocbIsCancelled(iocb)) |
1013 | goto put_rq; |
1014 | |
1015 | ring = kmap_atomic(info->ring_pages[0], KM_IRQ1); |
1016 | |
1017 | tail = info->tail; |
1018 | event = aio_ring_event(info, tail, KM_IRQ0); |
1019 | if (++tail >= info->nr) |
1020 | tail = 0; |
1021 | |
1022 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; |
1023 | event->data = iocb->ki_user_data; |
1024 | event->res = res; |
1025 | event->res2 = res2; |
1026 | |
1027 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", |
1028 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, |
1029 | res, res2); |
1030 | |
1031 | /* after flagging the request as done, we |
1032 | * must never even look at it again |
1033 | */ |
1034 | smp_wmb(); /* make event visible before updating tail */ |
1035 | |
1036 | info->tail = tail; |
1037 | ring->tail = tail; |
1038 | |
1039 | put_aio_ring_event(event, KM_IRQ0); |
1040 | kunmap_atomic(ring, KM_IRQ1); |
1041 | |
1042 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); |
1043 | |
1044 | /* |
1045 | * Check if the user asked us to deliver the result through an |
1046 | * eventfd. The eventfd_signal() function is safe to be called |
1047 | * from IRQ context. |
1048 | */ |
1049 | if (iocb->ki_eventfd != NULL) |
1050 | eventfd_signal(iocb->ki_eventfd, 1); |
1051 | |
1052 | put_rq: |
1053 | /* everything turned out well, dispose of the aiocb. */ |
1054 | ret = __aio_put_req(ctx, iocb); |
1055 | |
1056 | /* |
1057 | * We have to order our ring_info tail store above and test |
1058 | * of the wait list below outside the wait lock. This is |
1059 | * like in wake_up_bit() where clearing a bit has to be |
1060 | * ordered with the unlocked test. |
1061 | */ |
1062 | smp_mb(); |
1063 | |
1064 | if (waitqueue_active(&ctx->wait)) |
1065 | wake_up(&ctx->wait); |
1066 | |
1067 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
1068 | return ret; |
1069 | } |
1070 | EXPORT_SYMBOL(aio_complete); |
1071 | |
1072 | /* aio_read_evt |
1073 | * Pull an event off of the ioctx's event ring. Returns the number of |
1074 | * events fetched (0 or 1 ;-) |
1075 | * FIXME: make this use cmpxchg. |
1076 | * TODO: make the ringbuffer user mmap()able (requires FIXME). |
1077 | */ |
1078 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) |
1079 | { |
1080 | struct aio_ring_info *info = &ioctx->ring_info; |
1081 | struct aio_ring *ring; |
1082 | unsigned long head; |
1083 | int ret = 0; |
1084 | |
1085 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); |
1086 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", |
1087 | (unsigned long)ring->head, (unsigned long)ring->tail, |
1088 | (unsigned long)ring->nr); |
1089 | |
1090 | if (ring->head == ring->tail) |
1091 | goto out; |
1092 | |
1093 | spin_lock(&info->ring_lock); |
1094 | |
1095 | head = ring->head % info->nr; |
1096 | if (head != ring->tail) { |
1097 | struct io_event *evp = aio_ring_event(info, head, KM_USER1); |
1098 | *ent = *evp; |
1099 | head = (head + 1) % info->nr; |
1100 | smp_mb(); /* finish reading the event before updatng the head */ |
1101 | ring->head = head; |
1102 | ret = 1; |
1103 | put_aio_ring_event(evp, KM_USER1); |
1104 | } |
1105 | spin_unlock(&info->ring_lock); |
1106 | |
1107 | out: |
1108 | kunmap_atomic(ring, KM_USER0); |
1109 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, |
1110 | (unsigned long)ring->head, (unsigned long)ring->tail); |
1111 | return ret; |
1112 | } |
1113 | |
1114 | struct aio_timeout { |
1115 | struct timer_list timer; |
1116 | int timed_out; |
1117 | struct task_struct *p; |
1118 | }; |
1119 | |
1120 | static void timeout_func(unsigned long data) |
1121 | { |
1122 | struct aio_timeout *to = (struct aio_timeout *)data; |
1123 | |
1124 | to->timed_out = 1; |
1125 | wake_up_process(to->p); |
1126 | } |
1127 | |
1128 | static inline void init_timeout(struct aio_timeout *to) |
1129 | { |
1130 | setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); |
1131 | to->timed_out = 0; |
1132 | to->p = current; |
1133 | } |
1134 | |
1135 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, |
1136 | const struct timespec *ts) |
1137 | { |
1138 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); |
1139 | if (time_after(to->timer.expires, jiffies)) |
1140 | add_timer(&to->timer); |
1141 | else |
1142 | to->timed_out = 1; |
1143 | } |
1144 | |
1145 | static inline void clear_timeout(struct aio_timeout *to) |
1146 | { |
1147 | del_singleshot_timer_sync(&to->timer); |
1148 | } |
1149 | |
1150 | static int read_events(struct kioctx *ctx, |
1151 | long min_nr, long nr, |
1152 | struct io_event __user *event, |
1153 | struct timespec __user *timeout) |
1154 | { |
1155 | long start_jiffies = jiffies; |
1156 | struct task_struct *tsk = current; |
1157 | DECLARE_WAITQUEUE(wait, tsk); |
1158 | int ret; |
1159 | int i = 0; |
1160 | struct io_event ent; |
1161 | struct aio_timeout to; |
1162 | int retry = 0; |
1163 | |
1164 | /* needed to zero any padding within an entry (there shouldn't be |
1165 | * any, but C is fun! |
1166 | */ |
1167 | memset(&ent, 0, sizeof(ent)); |
1168 | retry: |
1169 | ret = 0; |
1170 | while (likely(i < nr)) { |
1171 | ret = aio_read_evt(ctx, &ent); |
1172 | if (unlikely(ret <= 0)) |
1173 | break; |
1174 | |
1175 | dprintk("read event: %Lx %Lx %Lx %Lx\n", |
1176 | ent.data, ent.obj, ent.res, ent.res2); |
1177 | |
1178 | /* Could we split the check in two? */ |
1179 | ret = -EFAULT; |
1180 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1181 | dprintk("aio: lost an event due to EFAULT.\n"); |
1182 | break; |
1183 | } |
1184 | ret = 0; |
1185 | |
1186 | /* Good, event copied to userland, update counts. */ |
1187 | event ++; |
1188 | i ++; |
1189 | } |
1190 | |
1191 | if (min_nr <= i) |
1192 | return i; |
1193 | if (ret) |
1194 | return ret; |
1195 | |
1196 | /* End fast path */ |
1197 | |
1198 | /* racey check, but it gets redone */ |
1199 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { |
1200 | retry = 1; |
1201 | aio_run_all_iocbs(ctx); |
1202 | goto retry; |
1203 | } |
1204 | |
1205 | init_timeout(&to); |
1206 | if (timeout) { |
1207 | struct timespec ts; |
1208 | ret = -EFAULT; |
1209 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) |
1210 | goto out; |
1211 | |
1212 | set_timeout(start_jiffies, &to, &ts); |
1213 | } |
1214 | |
1215 | while (likely(i < nr)) { |
1216 | add_wait_queue_exclusive(&ctx->wait, &wait); |
1217 | do { |
1218 | set_task_state(tsk, TASK_INTERRUPTIBLE); |
1219 | ret = aio_read_evt(ctx, &ent); |
1220 | if (ret) |
1221 | break; |
1222 | if (min_nr <= i) |
1223 | break; |
1224 | if (unlikely(ctx->dead)) { |
1225 | ret = -EINVAL; |
1226 | break; |
1227 | } |
1228 | if (to.timed_out) /* Only check after read evt */ |
1229 | break; |
1230 | /* Try to only show up in io wait if there are ops |
1231 | * in flight */ |
1232 | if (ctx->reqs_active) |
1233 | io_schedule(); |
1234 | else |
1235 | schedule(); |
1236 | if (signal_pending(tsk)) { |
1237 | ret = -EINTR; |
1238 | break; |
1239 | } |
1240 | /*ret = aio_read_evt(ctx, &ent);*/ |
1241 | } while (1) ; |
1242 | |
1243 | set_task_state(tsk, TASK_RUNNING); |
1244 | remove_wait_queue(&ctx->wait, &wait); |
1245 | |
1246 | if (unlikely(ret <= 0)) |
1247 | break; |
1248 | |
1249 | ret = -EFAULT; |
1250 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { |
1251 | dprintk("aio: lost an event due to EFAULT.\n"); |
1252 | break; |
1253 | } |
1254 | |
1255 | /* Good, event copied to userland, update counts. */ |
1256 | event ++; |
1257 | i ++; |
1258 | } |
1259 | |
1260 | if (timeout) |
1261 | clear_timeout(&to); |
1262 | out: |
1263 | destroy_timer_on_stack(&to.timer); |
1264 | return i ? i : ret; |
1265 | } |
1266 | |
1267 | /* Take an ioctx and remove it from the list of ioctx's. Protects |
1268 | * against races with itself via ->dead. |
1269 | */ |
1270 | static void io_destroy(struct kioctx *ioctx) |
1271 | { |
1272 | struct mm_struct *mm = current->mm; |
1273 | int was_dead; |
1274 | |
1275 | /* delete the entry from the list is someone else hasn't already */ |
1276 | spin_lock(&mm->ioctx_lock); |
1277 | was_dead = ioctx->dead; |
1278 | ioctx->dead = 1; |
1279 | hlist_del_rcu(&ioctx->list); |
1280 | spin_unlock(&mm->ioctx_lock); |
1281 | |
1282 | dprintk("aio_release(%p)\n", ioctx); |
1283 | if (likely(!was_dead)) |
1284 | put_ioctx(ioctx); /* twice for the list */ |
1285 | |
1286 | aio_cancel_all(ioctx); |
1287 | wait_for_all_aios(ioctx); |
1288 | |
1289 | /* |
1290 | * Wake up any waiters. The setting of ctx->dead must be seen |
1291 | * by other CPUs at this point. Right now, we rely on the |
1292 | * locking done by the above calls to ensure this consistency. |
1293 | */ |
1294 | wake_up_all(&ioctx->wait); |
1295 | put_ioctx(ioctx); /* once for the lookup */ |
1296 | } |
1297 | |
1298 | /* sys_io_setup: |
1299 | * Create an aio_context capable of receiving at least nr_events. |
1300 | * ctxp must not point to an aio_context that already exists, and |
1301 | * must be initialized to 0 prior to the call. On successful |
1302 | * creation of the aio_context, *ctxp is filled in with the resulting |
1303 | * handle. May fail with -EINVAL if *ctxp is not initialized, |
1304 | * if the specified nr_events exceeds internal limits. May fail |
1305 | * with -EAGAIN if the specified nr_events exceeds the user's limit |
1306 | * of available events. May fail with -ENOMEM if insufficient kernel |
1307 | * resources are available. May fail with -EFAULT if an invalid |
1308 | * pointer is passed for ctxp. Will fail with -ENOSYS if not |
1309 | * implemented. |
1310 | */ |
1311 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
1312 | { |
1313 | struct kioctx *ioctx = NULL; |
1314 | unsigned long ctx; |
1315 | long ret; |
1316 | |
1317 | ret = get_user(ctx, ctxp); |
1318 | if (unlikely(ret)) |
1319 | goto out; |
1320 | |
1321 | ret = -EINVAL; |
1322 | if (unlikely(ctx || nr_events == 0)) { |
1323 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", |
1324 | ctx, nr_events); |
1325 | goto out; |
1326 | } |
1327 | |
1328 | ioctx = ioctx_alloc(nr_events); |
1329 | ret = PTR_ERR(ioctx); |
1330 | if (!IS_ERR(ioctx)) { |
1331 | ret = put_user(ioctx->user_id, ctxp); |
1332 | if (!ret) |
1333 | return 0; |
1334 | |
1335 | get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ |
1336 | io_destroy(ioctx); |
1337 | } |
1338 | |
1339 | out: |
1340 | return ret; |
1341 | } |
1342 | |
1343 | /* sys_io_destroy: |
1344 | * Destroy the aio_context specified. May cancel any outstanding |
1345 | * AIOs and block on completion. Will fail with -ENOSYS if not |
1346 | * implemented. May fail with -EINVAL if the context pointed to |
1347 | * is invalid. |
1348 | */ |
1349 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
1350 | { |
1351 | struct kioctx *ioctx = lookup_ioctx(ctx); |
1352 | if (likely(NULL != ioctx)) { |
1353 | io_destroy(ioctx); |
1354 | return 0; |
1355 | } |
1356 | pr_debug("EINVAL: io_destroy: invalid context id\n"); |
1357 | return -EINVAL; |
1358 | } |
1359 | |
1360 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) |
1361 | { |
1362 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; |
1363 | |
1364 | BUG_ON(ret <= 0); |
1365 | |
1366 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { |
1367 | ssize_t this = min((ssize_t)iov->iov_len, ret); |
1368 | iov->iov_base += this; |
1369 | iov->iov_len -= this; |
1370 | iocb->ki_left -= this; |
1371 | ret -= this; |
1372 | if (iov->iov_len == 0) { |
1373 | iocb->ki_cur_seg++; |
1374 | iov++; |
1375 | } |
1376 | } |
1377 | |
1378 | /* the caller should not have done more io than what fit in |
1379 | * the remaining iovecs */ |
1380 | BUG_ON(ret > 0 && iocb->ki_left == 0); |
1381 | } |
1382 | |
1383 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) |
1384 | { |
1385 | struct file *file = iocb->ki_filp; |
1386 | struct address_space *mapping = file->f_mapping; |
1387 | struct inode *inode = mapping->host; |
1388 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, |
1389 | unsigned long, loff_t); |
1390 | ssize_t ret = 0; |
1391 | unsigned short opcode; |
1392 | |
1393 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || |
1394 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { |
1395 | rw_op = file->f_op->aio_read; |
1396 | opcode = IOCB_CMD_PREADV; |
1397 | } else { |
1398 | rw_op = file->f_op->aio_write; |
1399 | opcode = IOCB_CMD_PWRITEV; |
1400 | } |
1401 | |
1402 | /* This matches the pread()/pwrite() logic */ |
1403 | if (iocb->ki_pos < 0) |
1404 | return -EINVAL; |
1405 | |
1406 | do { |
1407 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], |
1408 | iocb->ki_nr_segs - iocb->ki_cur_seg, |
1409 | iocb->ki_pos); |
1410 | if (ret > 0) |
1411 | aio_advance_iovec(iocb, ret); |
1412 | |
1413 | /* retry all partial writes. retry partial reads as long as its a |
1414 | * regular file. */ |
1415 | } while (ret > 0 && iocb->ki_left > 0 && |
1416 | (opcode == IOCB_CMD_PWRITEV || |
1417 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); |
1418 | |
1419 | /* This means we must have transferred all that we could */ |
1420 | /* No need to retry anymore */ |
1421 | if ((ret == 0) || (iocb->ki_left == 0)) |
1422 | ret = iocb->ki_nbytes - iocb->ki_left; |
1423 | |
1424 | /* If we managed to write some out we return that, rather than |
1425 | * the eventual error. */ |
1426 | if (opcode == IOCB_CMD_PWRITEV |
1427 | && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY |
1428 | && iocb->ki_nbytes - iocb->ki_left) |
1429 | ret = iocb->ki_nbytes - iocb->ki_left; |
1430 | |
1431 | return ret; |
1432 | } |
1433 | |
1434 | static ssize_t aio_fdsync(struct kiocb *iocb) |
1435 | { |
1436 | struct file *file = iocb->ki_filp; |
1437 | ssize_t ret = -EINVAL; |
1438 | |
1439 | if (file->f_op->aio_fsync) |
1440 | ret = file->f_op->aio_fsync(iocb, 1); |
1441 | return ret; |
1442 | } |
1443 | |
1444 | static ssize_t aio_fsync(struct kiocb *iocb) |
1445 | { |
1446 | struct file *file = iocb->ki_filp; |
1447 | ssize_t ret = -EINVAL; |
1448 | |
1449 | if (file->f_op->aio_fsync) |
1450 | ret = file->f_op->aio_fsync(iocb, 0); |
1451 | return ret; |
1452 | } |
1453 | |
1454 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat) |
1455 | { |
1456 | ssize_t ret; |
1457 | |
1458 | #ifdef CONFIG_COMPAT |
1459 | if (compat) |
1460 | ret = compat_rw_copy_check_uvector(type, |
1461 | (struct compat_iovec __user *)kiocb->ki_buf, |
1462 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1463 | &kiocb->ki_iovec, 1); |
1464 | else |
1465 | #endif |
1466 | ret = rw_copy_check_uvector(type, |
1467 | (struct iovec __user *)kiocb->ki_buf, |
1468 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, |
1469 | &kiocb->ki_iovec, 1); |
1470 | if (ret < 0) |
1471 | goto out; |
1472 | |
1473 | kiocb->ki_nr_segs = kiocb->ki_nbytes; |
1474 | kiocb->ki_cur_seg = 0; |
1475 | /* ki_nbytes/left now reflect bytes instead of segs */ |
1476 | kiocb->ki_nbytes = ret; |
1477 | kiocb->ki_left = ret; |
1478 | |
1479 | ret = 0; |
1480 | out: |
1481 | return ret; |
1482 | } |
1483 | |
1484 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb) |
1485 | { |
1486 | kiocb->ki_iovec = &kiocb->ki_inline_vec; |
1487 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; |
1488 | kiocb->ki_iovec->iov_len = kiocb->ki_left; |
1489 | kiocb->ki_nr_segs = 1; |
1490 | kiocb->ki_cur_seg = 0; |
1491 | return 0; |
1492 | } |
1493 | |
1494 | /* |
1495 | * aio_setup_iocb: |
1496 | * Performs the initial checks and aio retry method |
1497 | * setup for the kiocb at the time of io submission. |
1498 | */ |
1499 | static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) |
1500 | { |
1501 | struct file *file = kiocb->ki_filp; |
1502 | ssize_t ret = 0; |
1503 | |
1504 | switch (kiocb->ki_opcode) { |
1505 | case IOCB_CMD_PREAD: |
1506 | ret = -EBADF; |
1507 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1508 | break; |
1509 | ret = -EFAULT; |
1510 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, |
1511 | kiocb->ki_left))) |
1512 | break; |
1513 | ret = security_file_permission(file, MAY_READ); |
1514 | if (unlikely(ret)) |
1515 | break; |
1516 | ret = aio_setup_single_vector(kiocb); |
1517 | if (ret) |
1518 | break; |
1519 | ret = -EINVAL; |
1520 | if (file->f_op->aio_read) |
1521 | kiocb->ki_retry = aio_rw_vect_retry; |
1522 | break; |
1523 | case IOCB_CMD_PWRITE: |
1524 | ret = -EBADF; |
1525 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1526 | break; |
1527 | ret = -EFAULT; |
1528 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, |
1529 | kiocb->ki_left))) |
1530 | break; |
1531 | ret = security_file_permission(file, MAY_WRITE); |
1532 | if (unlikely(ret)) |
1533 | break; |
1534 | ret = aio_setup_single_vector(kiocb); |
1535 | if (ret) |
1536 | break; |
1537 | ret = -EINVAL; |
1538 | if (file->f_op->aio_write) |
1539 | kiocb->ki_retry = aio_rw_vect_retry; |
1540 | break; |
1541 | case IOCB_CMD_PREADV: |
1542 | ret = -EBADF; |
1543 | if (unlikely(!(file->f_mode & FMODE_READ))) |
1544 | break; |
1545 | ret = security_file_permission(file, MAY_READ); |
1546 | if (unlikely(ret)) |
1547 | break; |
1548 | ret = aio_setup_vectored_rw(READ, kiocb, compat); |
1549 | if (ret) |
1550 | break; |
1551 | ret = -EINVAL; |
1552 | if (file->f_op->aio_read) |
1553 | kiocb->ki_retry = aio_rw_vect_retry; |
1554 | break; |
1555 | case IOCB_CMD_PWRITEV: |
1556 | ret = -EBADF; |
1557 | if (unlikely(!(file->f_mode & FMODE_WRITE))) |
1558 | break; |
1559 | ret = security_file_permission(file, MAY_WRITE); |
1560 | if (unlikely(ret)) |
1561 | break; |
1562 | ret = aio_setup_vectored_rw(WRITE, kiocb, compat); |
1563 | if (ret) |
1564 | break; |
1565 | ret = -EINVAL; |
1566 | if (file->f_op->aio_write) |
1567 | kiocb->ki_retry = aio_rw_vect_retry; |
1568 | break; |
1569 | case IOCB_CMD_FDSYNC: |
1570 | ret = -EINVAL; |
1571 | if (file->f_op->aio_fsync) |
1572 | kiocb->ki_retry = aio_fdsync; |
1573 | break; |
1574 | case IOCB_CMD_FSYNC: |
1575 | ret = -EINVAL; |
1576 | if (file->f_op->aio_fsync) |
1577 | kiocb->ki_retry = aio_fsync; |
1578 | break; |
1579 | default: |
1580 | dprintk("EINVAL: io_submit: no operation provided\n"); |
1581 | ret = -EINVAL; |
1582 | } |
1583 | |
1584 | if (!kiocb->ki_retry) |
1585 | return ret; |
1586 | |
1587 | return 0; |
1588 | } |
1589 | |
1590 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
1591 | struct iocb *iocb, struct kiocb_batch *batch, |
1592 | bool compat) |
1593 | { |
1594 | struct kiocb *req; |
1595 | struct file *file; |
1596 | ssize_t ret; |
1597 | |
1598 | /* enforce forwards compatibility on users */ |
1599 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { |
1600 | pr_debug("EINVAL: io_submit: reserve field set\n"); |
1601 | return -EINVAL; |
1602 | } |
1603 | |
1604 | /* prevent overflows */ |
1605 | if (unlikely( |
1606 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || |
1607 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || |
1608 | ((ssize_t)iocb->aio_nbytes < 0) |
1609 | )) { |
1610 | pr_debug("EINVAL: io_submit: overflow check\n"); |
1611 | return -EINVAL; |
1612 | } |
1613 | |
1614 | file = fget(iocb->aio_fildes); |
1615 | if (unlikely(!file)) |
1616 | return -EBADF; |
1617 | |
1618 | req = aio_get_req(ctx, batch); /* returns with 2 references to req */ |
1619 | if (unlikely(!req)) { |
1620 | fput(file); |
1621 | return -EAGAIN; |
1622 | } |
1623 | req->ki_filp = file; |
1624 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
1625 | /* |
1626 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an |
1627 | * instance of the file* now. The file descriptor must be |
1628 | * an eventfd() fd, and will be signaled for each completed |
1629 | * event using the eventfd_signal() function. |
1630 | */ |
1631 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); |
1632 | if (IS_ERR(req->ki_eventfd)) { |
1633 | ret = PTR_ERR(req->ki_eventfd); |
1634 | req->ki_eventfd = NULL; |
1635 | goto out_put_req; |
1636 | } |
1637 | } |
1638 | |
1639 | ret = put_user(req->ki_key, &user_iocb->aio_key); |
1640 | if (unlikely(ret)) { |
1641 | dprintk("EFAULT: aio_key\n"); |
1642 | goto out_put_req; |
1643 | } |
1644 | |
1645 | req->ki_obj.user = user_iocb; |
1646 | req->ki_user_data = iocb->aio_data; |
1647 | req->ki_pos = iocb->aio_offset; |
1648 | |
1649 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; |
1650 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; |
1651 | req->ki_opcode = iocb->aio_lio_opcode; |
1652 | |
1653 | ret = aio_setup_iocb(req, compat); |
1654 | |
1655 | if (ret) |
1656 | goto out_put_req; |
1657 | |
1658 | spin_lock_irq(&ctx->ctx_lock); |
1659 | /* |
1660 | * We could have raced with io_destroy() and are currently holding a |
1661 | * reference to ctx which should be destroyed. We cannot submit IO |
1662 | * since ctx gets freed as soon as io_submit() puts its reference. The |
1663 | * check here is reliable: io_destroy() sets ctx->dead before waiting |
1664 | * for outstanding IO and the barrier between these two is realized by |
1665 | * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we |
1666 | * increment ctx->reqs_active before checking for ctx->dead and the |
1667 | * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we |
1668 | * don't see ctx->dead set here, io_destroy() waits for our IO to |
1669 | * finish. |
1670 | */ |
1671 | if (ctx->dead) { |
1672 | spin_unlock_irq(&ctx->ctx_lock); |
1673 | ret = -EINVAL; |
1674 | goto out_put_req; |
1675 | } |
1676 | aio_run_iocb(req); |
1677 | if (!list_empty(&ctx->run_list)) { |
1678 | /* drain the run list */ |
1679 | while (__aio_run_iocbs(ctx)) |
1680 | ; |
1681 | } |
1682 | spin_unlock_irq(&ctx->ctx_lock); |
1683 | |
1684 | aio_put_req(req); /* drop extra ref to req */ |
1685 | return 0; |
1686 | |
1687 | out_put_req: |
1688 | aio_put_req(req); /* drop extra ref to req */ |
1689 | aio_put_req(req); /* drop i/o ref to req */ |
1690 | return ret; |
1691 | } |
1692 | |
1693 | long do_io_submit(aio_context_t ctx_id, long nr, |
1694 | struct iocb __user *__user *iocbpp, bool compat) |
1695 | { |
1696 | struct kioctx *ctx; |
1697 | long ret = 0; |
1698 | int i = 0; |
1699 | struct blk_plug plug; |
1700 | struct kiocb_batch batch; |
1701 | |
1702 | if (unlikely(nr < 0)) |
1703 | return -EINVAL; |
1704 | |
1705 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
1706 | nr = LONG_MAX/sizeof(*iocbpp); |
1707 | |
1708 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
1709 | return -EFAULT; |
1710 | |
1711 | ctx = lookup_ioctx(ctx_id); |
1712 | if (unlikely(!ctx)) { |
1713 | pr_debug("EINVAL: io_submit: invalid context id\n"); |
1714 | return -EINVAL; |
1715 | } |
1716 | |
1717 | kiocb_batch_init(&batch, nr); |
1718 | |
1719 | blk_start_plug(&plug); |
1720 | |
1721 | /* |
1722 | * AKPM: should this return a partial result if some of the IOs were |
1723 | * successfully submitted? |
1724 | */ |
1725 | for (i=0; i<nr; i++) { |
1726 | struct iocb __user *user_iocb; |
1727 | struct iocb tmp; |
1728 | |
1729 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { |
1730 | ret = -EFAULT; |
1731 | break; |
1732 | } |
1733 | |
1734 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { |
1735 | ret = -EFAULT; |
1736 | break; |
1737 | } |
1738 | |
1739 | ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat); |
1740 | if (ret) |
1741 | break; |
1742 | } |
1743 | blk_finish_plug(&plug); |
1744 | |
1745 | kiocb_batch_free(&batch); |
1746 | put_ioctx(ctx); |
1747 | return i ? i : ret; |
1748 | } |
1749 | |
1750 | /* sys_io_submit: |
1751 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns |
1752 | * the number of iocbs queued. May return -EINVAL if the aio_context |
1753 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at |
1754 | * *iocbpp[0] is not properly initialized, if the operation specified |
1755 | * is invalid for the file descriptor in the iocb. May fail with |
1756 | * -EFAULT if any of the data structures point to invalid data. May |
1757 | * fail with -EBADF if the file descriptor specified in the first |
1758 | * iocb is invalid. May fail with -EAGAIN if insufficient resources |
1759 | * are available to queue any iocbs. Will return 0 if nr is 0. Will |
1760 | * fail with -ENOSYS if not implemented. |
1761 | */ |
1762 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, |
1763 | struct iocb __user * __user *, iocbpp) |
1764 | { |
1765 | return do_io_submit(ctx_id, nr, iocbpp, 0); |
1766 | } |
1767 | |
1768 | /* lookup_kiocb |
1769 | * Finds a given iocb for cancellation. |
1770 | */ |
1771 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, |
1772 | u32 key) |
1773 | { |
1774 | struct list_head *pos; |
1775 | |
1776 | assert_spin_locked(&ctx->ctx_lock); |
1777 | |
1778 | /* TODO: use a hash or array, this sucks. */ |
1779 | list_for_each(pos, &ctx->active_reqs) { |
1780 | struct kiocb *kiocb = list_kiocb(pos); |
1781 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) |
1782 | return kiocb; |
1783 | } |
1784 | return NULL; |
1785 | } |
1786 | |
1787 | /* sys_io_cancel: |
1788 | * Attempts to cancel an iocb previously passed to io_submit. If |
1789 | * the operation is successfully cancelled, the resulting event is |
1790 | * copied into the memory pointed to by result without being placed |
1791 | * into the completion queue and 0 is returned. May fail with |
1792 | * -EFAULT if any of the data structures pointed to are invalid. |
1793 | * May fail with -EINVAL if aio_context specified by ctx_id is |
1794 | * invalid. May fail with -EAGAIN if the iocb specified was not |
1795 | * cancelled. Will fail with -ENOSYS if not implemented. |
1796 | */ |
1797 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
1798 | struct io_event __user *, result) |
1799 | { |
1800 | int (*cancel)(struct kiocb *iocb, struct io_event *res); |
1801 | struct kioctx *ctx; |
1802 | struct kiocb *kiocb; |
1803 | u32 key; |
1804 | int ret; |
1805 | |
1806 | ret = get_user(key, &iocb->aio_key); |
1807 | if (unlikely(ret)) |
1808 | return -EFAULT; |
1809 | |
1810 | ctx = lookup_ioctx(ctx_id); |
1811 | if (unlikely(!ctx)) |
1812 | return -EINVAL; |
1813 | |
1814 | spin_lock_irq(&ctx->ctx_lock); |
1815 | ret = -EAGAIN; |
1816 | kiocb = lookup_kiocb(ctx, iocb, key); |
1817 | if (kiocb && kiocb->ki_cancel) { |
1818 | cancel = kiocb->ki_cancel; |
1819 | kiocb->ki_users ++; |
1820 | kiocbSetCancelled(kiocb); |
1821 | } else |
1822 | cancel = NULL; |
1823 | spin_unlock_irq(&ctx->ctx_lock); |
1824 | |
1825 | if (NULL != cancel) { |
1826 | struct io_event tmp; |
1827 | pr_debug("calling cancel\n"); |
1828 | memset(&tmp, 0, sizeof(tmp)); |
1829 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; |
1830 | tmp.data = kiocb->ki_user_data; |
1831 | ret = cancel(kiocb, &tmp); |
1832 | if (!ret) { |
1833 | /* Cancellation succeeded -- copy the result |
1834 | * into the user's buffer. |
1835 | */ |
1836 | if (copy_to_user(result, &tmp, sizeof(tmp))) |
1837 | ret = -EFAULT; |
1838 | } |
1839 | } else |
1840 | ret = -EINVAL; |
1841 | |
1842 | put_ioctx(ctx); |
1843 | |
1844 | return ret; |
1845 | } |
1846 | |
1847 | /* io_getevents: |
1848 | * Attempts to read at least min_nr events and up to nr events from |
1849 | * the completion queue for the aio_context specified by ctx_id. If |
1850 | * it succeeds, the number of read events is returned. May fail with |
1851 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is |
1852 | * out of range, if timeout is out of range. May fail with -EFAULT |
1853 | * if any of the memory specified is invalid. May return 0 or |
1854 | * < min_nr if the timeout specified by timeout has elapsed |
1855 | * before sufficient events are available, where timeout == NULL |
1856 | * specifies an infinite timeout. Note that the timeout pointed to by |
1857 | * timeout is relative and will be updated if not NULL and the |
1858 | * operation blocks. Will fail with -ENOSYS if not implemented. |
1859 | */ |
1860 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
1861 | long, min_nr, |
1862 | long, nr, |
1863 | struct io_event __user *, events, |
1864 | struct timespec __user *, timeout) |
1865 | { |
1866 | struct kioctx *ioctx = lookup_ioctx(ctx_id); |
1867 | long ret = -EINVAL; |
1868 | |
1869 | if (likely(ioctx)) { |
1870 | if (likely(min_nr <= nr && min_nr >= 0)) |
1871 | ret = read_events(ioctx, min_nr, nr, events, timeout); |
1872 | put_ioctx(ioctx); |
1873 | } |
1874 | |
1875 | asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); |
1876 | return ret; |
1877 | } |
1878 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9