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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 | ||
40 | #include <asm/kmap_types.h> | |
41 | #include <asm/uaccess.h> | |
42 | ||
43 | #if DEBUG > 1 | |
44 | #define dprintk printk | |
45 | #else | |
46 | #define dprintk(x...) do { ; } while (0) | |
47 | #endif | |
48 | ||
49 | /*------ sysctl variables----*/ | |
50 | static DEFINE_SPINLOCK(aio_nr_lock); | |
51 | unsigned long aio_nr; /* current system wide number of aio requests */ | |
52 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ | |
53 | /*----end sysctl variables---*/ | |
54 | ||
55 | static struct kmem_cache *kiocb_cachep; | |
56 | static struct kmem_cache *kioctx_cachep; | |
57 | ||
58 | static struct workqueue_struct *aio_wq; | |
59 | ||
60 | /* Used for rare fput completion. */ | |
61 | static void aio_fput_routine(struct work_struct *); | |
62 | static DECLARE_WORK(fput_work, aio_fput_routine); | |
63 | ||
64 | static DEFINE_SPINLOCK(fput_lock); | |
65 | static LIST_HEAD(fput_head); | |
66 | ||
67 | #define AIO_BATCH_HASH_BITS 3 /* allocated on-stack, so don't go crazy */ | |
68 | #define AIO_BATCH_HASH_SIZE (1 << AIO_BATCH_HASH_BITS) | |
69 | struct aio_batch_entry { | |
70 | struct hlist_node list; | |
71 | struct address_space *mapping; | |
72 | }; | |
73 | mempool_t *abe_pool; | |
74 | ||
75 | static void aio_kick_handler(struct work_struct *); | |
76 | static void aio_queue_work(struct kioctx *); | |
77 | ||
78 | /* aio_setup | |
79 | * Creates the slab caches used by the aio routines, panic on | |
80 | * failure as this is done early during the boot sequence. | |
81 | */ | |
82 | static int __init aio_setup(void) | |
83 | { | |
84 | kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); | |
85 | kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); | |
86 | ||
87 | aio_wq = create_workqueue("aio"); | |
88 | abe_pool = mempool_create_kmalloc_pool(1, sizeof(struct aio_batch_entry)); | |
89 | BUG_ON(!abe_pool); | |
90 | ||
91 | pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page)); | |
92 | ||
93 | return 0; | |
94 | } | |
95 | __initcall(aio_setup); | |
96 | ||
97 | static void aio_free_ring(struct kioctx *ctx) | |
98 | { | |
99 | struct aio_ring_info *info = &ctx->ring_info; | |
100 | long i; | |
101 | ||
102 | for (i=0; i<info->nr_pages; i++) | |
103 | put_page(info->ring_pages[i]); | |
104 | ||
105 | if (info->mmap_size) { | |
106 | down_write(&ctx->mm->mmap_sem); | |
107 | do_munmap(ctx->mm, info->mmap_base, info->mmap_size); | |
108 | up_write(&ctx->mm->mmap_sem); | |
109 | } | |
110 | ||
111 | if (info->ring_pages && info->ring_pages != info->internal_pages) | |
112 | kfree(info->ring_pages); | |
113 | info->ring_pages = NULL; | |
114 | info->nr = 0; | |
115 | } | |
116 | ||
117 | static int aio_setup_ring(struct kioctx *ctx) | |
118 | { | |
119 | struct aio_ring *ring; | |
120 | struct aio_ring_info *info = &ctx->ring_info; | |
121 | unsigned nr_events = ctx->max_reqs; | |
122 | unsigned long size; | |
123 | int nr_pages; | |
124 | ||
125 | /* Compensate for the ring buffer's head/tail overlap entry */ | |
126 | nr_events += 2; /* 1 is required, 2 for good luck */ | |
127 | ||
128 | size = sizeof(struct aio_ring); | |
129 | size += sizeof(struct io_event) * nr_events; | |
130 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; | |
131 | ||
132 | if (nr_pages < 0) | |
133 | return -EINVAL; | |
134 | ||
135 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); | |
136 | ||
137 | info->nr = 0; | |
138 | info->ring_pages = info->internal_pages; | |
139 | if (nr_pages > AIO_RING_PAGES) { | |
140 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); | |
141 | if (!info->ring_pages) | |
142 | return -ENOMEM; | |
143 | } | |
144 | ||
145 | info->mmap_size = nr_pages * PAGE_SIZE; | |
146 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); | |
147 | down_write(&ctx->mm->mmap_sem); | |
148 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, | |
149 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, | |
150 | 0); | |
151 | if (IS_ERR((void *)info->mmap_base)) { | |
152 | up_write(&ctx->mm->mmap_sem); | |
153 | info->mmap_size = 0; | |
154 | aio_free_ring(ctx); | |
155 | return -EAGAIN; | |
156 | } | |
157 | ||
158 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); | |
159 | info->nr_pages = get_user_pages(current, ctx->mm, | |
160 | info->mmap_base, nr_pages, | |
161 | 1, 0, info->ring_pages, NULL); | |
162 | up_write(&ctx->mm->mmap_sem); | |
163 | ||
164 | if (unlikely(info->nr_pages != nr_pages)) { | |
165 | aio_free_ring(ctx); | |
166 | return -EAGAIN; | |
167 | } | |
168 | ||
169 | ctx->user_id = info->mmap_base; | |
170 | ||
171 | info->nr = nr_events; /* trusted copy */ | |
172 | ||
173 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); | |
174 | ring->nr = nr_events; /* user copy */ | |
175 | ring->id = ctx->user_id; | |
176 | ring->head = ring->tail = 0; | |
177 | ring->magic = AIO_RING_MAGIC; | |
178 | ring->compat_features = AIO_RING_COMPAT_FEATURES; | |
179 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; | |
180 | ring->header_length = sizeof(struct aio_ring); | |
181 | kunmap_atomic(ring, KM_USER0); | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
186 | ||
187 | /* aio_ring_event: returns a pointer to the event at the given index from | |
188 | * kmap_atomic(, km). Release the pointer with put_aio_ring_event(); | |
189 | */ | |
190 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) | |
191 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) | |
192 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) | |
193 | ||
194 | #define aio_ring_event(info, nr, km) ({ \ | |
195 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ | |
196 | struct io_event *__event; \ | |
197 | __event = kmap_atomic( \ | |
198 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \ | |
199 | __event += pos % AIO_EVENTS_PER_PAGE; \ | |
200 | __event; \ | |
201 | }) | |
202 | ||
203 | #define put_aio_ring_event(event, km) do { \ | |
204 | struct io_event *__event = (event); \ | |
205 | (void)__event; \ | |
206 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \ | |
207 | } while(0) | |
208 | ||
209 | static void ctx_rcu_free(struct rcu_head *head) | |
210 | { | |
211 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); | |
212 | unsigned nr_events = ctx->max_reqs; | |
213 | ||
214 | kmem_cache_free(kioctx_cachep, ctx); | |
215 | ||
216 | if (nr_events) { | |
217 | spin_lock(&aio_nr_lock); | |
218 | BUG_ON(aio_nr - nr_events > aio_nr); | |
219 | aio_nr -= nr_events; | |
220 | spin_unlock(&aio_nr_lock); | |
221 | } | |
222 | } | |
223 | ||
224 | /* __put_ioctx | |
225 | * Called when the last user of an aio context has gone away, | |
226 | * and the struct needs to be freed. | |
227 | */ | |
228 | static void __put_ioctx(struct kioctx *ctx) | |
229 | { | |
230 | BUG_ON(ctx->reqs_active); | |
231 | ||
232 | cancel_delayed_work(&ctx->wq); | |
233 | cancel_work_sync(&ctx->wq.work); | |
234 | aio_free_ring(ctx); | |
235 | mmdrop(ctx->mm); | |
236 | ctx->mm = NULL; | |
237 | pr_debug("__put_ioctx: freeing %p\n", ctx); | |
238 | call_rcu(&ctx->rcu_head, ctx_rcu_free); | |
239 | } | |
240 | ||
241 | #define get_ioctx(kioctx) do { \ | |
242 | BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ | |
243 | atomic_inc(&(kioctx)->users); \ | |
244 | } while (0) | |
245 | #define put_ioctx(kioctx) do { \ | |
246 | BUG_ON(atomic_read(&(kioctx)->users) <= 0); \ | |
247 | if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \ | |
248 | __put_ioctx(kioctx); \ | |
249 | } while (0) | |
250 | ||
251 | /* ioctx_alloc | |
252 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. | |
253 | */ | |
254 | static struct kioctx *ioctx_alloc(unsigned nr_events) | |
255 | { | |
256 | struct mm_struct *mm; | |
257 | struct kioctx *ctx; | |
258 | int did_sync = 0; | |
259 | ||
260 | /* Prevent overflows */ | |
261 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || | |
262 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { | |
263 | pr_debug("ENOMEM: nr_events too high\n"); | |
264 | return ERR_PTR(-EINVAL); | |
265 | } | |
266 | ||
267 | if ((unsigned long)nr_events > aio_max_nr) | |
268 | return ERR_PTR(-EAGAIN); | |
269 | ||
270 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); | |
271 | if (!ctx) | |
272 | return ERR_PTR(-ENOMEM); | |
273 | ||
274 | ctx->max_reqs = nr_events; | |
275 | mm = ctx->mm = current->mm; | |
276 | atomic_inc(&mm->mm_count); | |
277 | ||
278 | atomic_set(&ctx->users, 1); | |
279 | spin_lock_init(&ctx->ctx_lock); | |
280 | spin_lock_init(&ctx->ring_info.ring_lock); | |
281 | init_waitqueue_head(&ctx->wait); | |
282 | ||
283 | INIT_LIST_HEAD(&ctx->active_reqs); | |
284 | INIT_LIST_HEAD(&ctx->run_list); | |
285 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); | |
286 | ||
287 | if (aio_setup_ring(ctx) < 0) | |
288 | goto out_freectx; | |
289 | ||
290 | /* limit the number of system wide aios */ | |
291 | do { | |
292 | spin_lock_bh(&aio_nr_lock); | |
293 | if (aio_nr + nr_events > aio_max_nr || | |
294 | aio_nr + nr_events < aio_nr) | |
295 | ctx->max_reqs = 0; | |
296 | else | |
297 | aio_nr += ctx->max_reqs; | |
298 | spin_unlock_bh(&aio_nr_lock); | |
299 | if (ctx->max_reqs || did_sync) | |
300 | break; | |
301 | ||
302 | /* wait for rcu callbacks to have completed before giving up */ | |
303 | synchronize_rcu(); | |
304 | did_sync = 1; | |
305 | ctx->max_reqs = nr_events; | |
306 | } while (1); | |
307 | ||
308 | if (ctx->max_reqs == 0) | |
309 | goto out_cleanup; | |
310 | ||
311 | /* now link into global list. */ | |
312 | spin_lock(&mm->ioctx_lock); | |
313 | hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); | |
314 | spin_unlock(&mm->ioctx_lock); | |
315 | ||
316 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", | |
317 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); | |
318 | return ctx; | |
319 | ||
320 | out_cleanup: | |
321 | __put_ioctx(ctx); | |
322 | return ERR_PTR(-EAGAIN); | |
323 | ||
324 | out_freectx: | |
325 | mmdrop(mm); | |
326 | kmem_cache_free(kioctx_cachep, ctx); | |
327 | ctx = ERR_PTR(-ENOMEM); | |
328 | ||
329 | dprintk("aio: error allocating ioctx %p\n", ctx); | |
330 | return ctx; | |
331 | } | |
332 | ||
333 | /* aio_cancel_all | |
334 | * Cancels all outstanding aio requests on an aio context. Used | |
335 | * when the processes owning a context have all exited to encourage | |
336 | * the rapid destruction of the kioctx. | |
337 | */ | |
338 | static void aio_cancel_all(struct kioctx *ctx) | |
339 | { | |
340 | int (*cancel)(struct kiocb *, struct io_event *); | |
341 | struct io_event res; | |
342 | spin_lock_irq(&ctx->ctx_lock); | |
343 | ctx->dead = 1; | |
344 | while (!list_empty(&ctx->active_reqs)) { | |
345 | struct list_head *pos = ctx->active_reqs.next; | |
346 | struct kiocb *iocb = list_kiocb(pos); | |
347 | list_del_init(&iocb->ki_list); | |
348 | cancel = iocb->ki_cancel; | |
349 | kiocbSetCancelled(iocb); | |
350 | if (cancel) { | |
351 | iocb->ki_users++; | |
352 | spin_unlock_irq(&ctx->ctx_lock); | |
353 | cancel(iocb, &res); | |
354 | spin_lock_irq(&ctx->ctx_lock); | |
355 | } | |
356 | } | |
357 | spin_unlock_irq(&ctx->ctx_lock); | |
358 | } | |
359 | ||
360 | static void wait_for_all_aios(struct kioctx *ctx) | |
361 | { | |
362 | struct task_struct *tsk = current; | |
363 | DECLARE_WAITQUEUE(wait, tsk); | |
364 | ||
365 | spin_lock_irq(&ctx->ctx_lock); | |
366 | if (!ctx->reqs_active) | |
367 | goto out; | |
368 | ||
369 | add_wait_queue(&ctx->wait, &wait); | |
370 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
371 | while (ctx->reqs_active) { | |
372 | spin_unlock_irq(&ctx->ctx_lock); | |
373 | io_schedule(); | |
374 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
375 | spin_lock_irq(&ctx->ctx_lock); | |
376 | } | |
377 | __set_task_state(tsk, TASK_RUNNING); | |
378 | remove_wait_queue(&ctx->wait, &wait); | |
379 | ||
380 | out: | |
381 | spin_unlock_irq(&ctx->ctx_lock); | |
382 | } | |
383 | ||
384 | /* wait_on_sync_kiocb: | |
385 | * Waits on the given sync kiocb to complete. | |
386 | */ | |
387 | ssize_t wait_on_sync_kiocb(struct kiocb *iocb) | |
388 | { | |
389 | while (iocb->ki_users) { | |
390 | set_current_state(TASK_UNINTERRUPTIBLE); | |
391 | if (!iocb->ki_users) | |
392 | break; | |
393 | io_schedule(); | |
394 | } | |
395 | __set_current_state(TASK_RUNNING); | |
396 | return iocb->ki_user_data; | |
397 | } | |
398 | EXPORT_SYMBOL(wait_on_sync_kiocb); | |
399 | ||
400 | /* exit_aio: called when the last user of mm goes away. At this point, | |
401 | * there is no way for any new requests to be submited or any of the | |
402 | * io_* syscalls to be called on the context. However, there may be | |
403 | * outstanding requests which hold references to the context; as they | |
404 | * go away, they will call put_ioctx and release any pinned memory | |
405 | * associated with the request (held via struct page * references). | |
406 | */ | |
407 | void exit_aio(struct mm_struct *mm) | |
408 | { | |
409 | struct kioctx *ctx; | |
410 | ||
411 | while (!hlist_empty(&mm->ioctx_list)) { | |
412 | ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); | |
413 | hlist_del_rcu(&ctx->list); | |
414 | ||
415 | aio_cancel_all(ctx); | |
416 | ||
417 | wait_for_all_aios(ctx); | |
418 | /* | |
419 | * Ensure we don't leave the ctx on the aio_wq | |
420 | */ | |
421 | cancel_work_sync(&ctx->wq.work); | |
422 | ||
423 | if (1 != atomic_read(&ctx->users)) | |
424 | printk(KERN_DEBUG | |
425 | "exit_aio:ioctx still alive: %d %d %d\n", | |
426 | atomic_read(&ctx->users), ctx->dead, | |
427 | ctx->reqs_active); | |
428 | put_ioctx(ctx); | |
429 | } | |
430 | } | |
431 | ||
432 | /* aio_get_req | |
433 | * Allocate a slot for an aio request. Increments the users count | |
434 | * of the kioctx so that the kioctx stays around until all requests are | |
435 | * complete. Returns NULL if no requests are free. | |
436 | * | |
437 | * Returns with kiocb->users set to 2. The io submit code path holds | |
438 | * an extra reference while submitting the i/o. | |
439 | * This prevents races between the aio code path referencing the | |
440 | * req (after submitting it) and aio_complete() freeing the req. | |
441 | */ | |
442 | static struct kiocb *__aio_get_req(struct kioctx *ctx) | |
443 | { | |
444 | struct kiocb *req = NULL; | |
445 | struct aio_ring *ring; | |
446 | int okay = 0; | |
447 | ||
448 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); | |
449 | if (unlikely(!req)) | |
450 | return NULL; | |
451 | ||
452 | req->ki_flags = 0; | |
453 | req->ki_users = 2; | |
454 | req->ki_key = 0; | |
455 | req->ki_ctx = ctx; | |
456 | req->ki_cancel = NULL; | |
457 | req->ki_retry = NULL; | |
458 | req->ki_dtor = NULL; | |
459 | req->private = NULL; | |
460 | req->ki_iovec = NULL; | |
461 | INIT_LIST_HEAD(&req->ki_run_list); | |
462 | req->ki_eventfd = NULL; | |
463 | ||
464 | /* Check if the completion queue has enough free space to | |
465 | * accept an event from this io. | |
466 | */ | |
467 | spin_lock_irq(&ctx->ctx_lock); | |
468 | ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0); | |
469 | if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) { | |
470 | list_add(&req->ki_list, &ctx->active_reqs); | |
471 | ctx->reqs_active++; | |
472 | okay = 1; | |
473 | } | |
474 | kunmap_atomic(ring, KM_USER0); | |
475 | spin_unlock_irq(&ctx->ctx_lock); | |
476 | ||
477 | if (!okay) { | |
478 | kmem_cache_free(kiocb_cachep, req); | |
479 | req = NULL; | |
480 | } | |
481 | ||
482 | return req; | |
483 | } | |
484 | ||
485 | static inline struct kiocb *aio_get_req(struct kioctx *ctx) | |
486 | { | |
487 | struct kiocb *req; | |
488 | /* Handle a potential starvation case -- should be exceedingly rare as | |
489 | * requests will be stuck on fput_head only if the aio_fput_routine is | |
490 | * delayed and the requests were the last user of the struct file. | |
491 | */ | |
492 | req = __aio_get_req(ctx); | |
493 | if (unlikely(NULL == req)) { | |
494 | aio_fput_routine(NULL); | |
495 | req = __aio_get_req(ctx); | |
496 | } | |
497 | return req; | |
498 | } | |
499 | ||
500 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) | |
501 | { | |
502 | assert_spin_locked(&ctx->ctx_lock); | |
503 | ||
504 | if (req->ki_eventfd != NULL) | |
505 | eventfd_ctx_put(req->ki_eventfd); | |
506 | if (req->ki_dtor) | |
507 | req->ki_dtor(req); | |
508 | if (req->ki_iovec != &req->ki_inline_vec) | |
509 | kfree(req->ki_iovec); | |
510 | kmem_cache_free(kiocb_cachep, req); | |
511 | ctx->reqs_active--; | |
512 | ||
513 | if (unlikely(!ctx->reqs_active && ctx->dead)) | |
514 | wake_up(&ctx->wait); | |
515 | } | |
516 | ||
517 | static void aio_fput_routine(struct work_struct *data) | |
518 | { | |
519 | spin_lock_irq(&fput_lock); | |
520 | while (likely(!list_empty(&fput_head))) { | |
521 | struct kiocb *req = list_kiocb(fput_head.next); | |
522 | struct kioctx *ctx = req->ki_ctx; | |
523 | ||
524 | list_del(&req->ki_list); | |
525 | spin_unlock_irq(&fput_lock); | |
526 | ||
527 | /* Complete the fput(s) */ | |
528 | if (req->ki_filp != NULL) | |
529 | __fput(req->ki_filp); | |
530 | ||
531 | /* Link the iocb into the context's free list */ | |
532 | spin_lock_irq(&ctx->ctx_lock); | |
533 | really_put_req(ctx, req); | |
534 | spin_unlock_irq(&ctx->ctx_lock); | |
535 | ||
536 | put_ioctx(ctx); | |
537 | spin_lock_irq(&fput_lock); | |
538 | } | |
539 | spin_unlock_irq(&fput_lock); | |
540 | } | |
541 | ||
542 | /* __aio_put_req | |
543 | * Returns true if this put was the last user of the request. | |
544 | */ | |
545 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) | |
546 | { | |
547 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", | |
548 | req, atomic_long_read(&req->ki_filp->f_count)); | |
549 | ||
550 | assert_spin_locked(&ctx->ctx_lock); | |
551 | ||
552 | req->ki_users--; | |
553 | BUG_ON(req->ki_users < 0); | |
554 | if (likely(req->ki_users)) | |
555 | return 0; | |
556 | list_del(&req->ki_list); /* remove from active_reqs */ | |
557 | req->ki_cancel = NULL; | |
558 | req->ki_retry = NULL; | |
559 | ||
560 | /* | |
561 | * Try to optimize the aio and eventfd file* puts, by avoiding to | |
562 | * schedule work in case it is not __fput() time. In normal cases, | |
563 | * we would not be holding the last reference to the file*, so | |
564 | * this function will be executed w/out any aio kthread wakeup. | |
565 | */ | |
566 | if (unlikely(atomic_long_dec_and_test(&req->ki_filp->f_count))) { | |
567 | get_ioctx(ctx); | |
568 | spin_lock(&fput_lock); | |
569 | list_add(&req->ki_list, &fput_head); | |
570 | spin_unlock(&fput_lock); | |
571 | queue_work(aio_wq, &fput_work); | |
572 | } else { | |
573 | req->ki_filp = NULL; | |
574 | really_put_req(ctx, req); | |
575 | } | |
576 | return 1; | |
577 | } | |
578 | ||
579 | /* aio_put_req | |
580 | * Returns true if this put was the last user of the kiocb, | |
581 | * false if the request is still in use. | |
582 | */ | |
583 | int aio_put_req(struct kiocb *req) | |
584 | { | |
585 | struct kioctx *ctx = req->ki_ctx; | |
586 | int ret; | |
587 | spin_lock_irq(&ctx->ctx_lock); | |
588 | ret = __aio_put_req(ctx, req); | |
589 | spin_unlock_irq(&ctx->ctx_lock); | |
590 | return ret; | |
591 | } | |
592 | EXPORT_SYMBOL(aio_put_req); | |
593 | ||
594 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) | |
595 | { | |
596 | struct mm_struct *mm = current->mm; | |
597 | struct kioctx *ctx, *ret = NULL; | |
598 | struct hlist_node *n; | |
599 | ||
600 | rcu_read_lock(); | |
601 | ||
602 | hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { | |
603 | if (ctx->user_id == ctx_id && !ctx->dead) { | |
604 | get_ioctx(ctx); | |
605 | ret = ctx; | |
606 | break; | |
607 | } | |
608 | } | |
609 | ||
610 | rcu_read_unlock(); | |
611 | return ret; | |
612 | } | |
613 | ||
614 | /* | |
615 | * Queue up a kiocb to be retried. Assumes that the kiocb | |
616 | * has already been marked as kicked, and places it on | |
617 | * the retry run list for the corresponding ioctx, if it | |
618 | * isn't already queued. Returns 1 if it actually queued | |
619 | * the kiocb (to tell the caller to activate the work | |
620 | * queue to process it), or 0, if it found that it was | |
621 | * already queued. | |
622 | */ | |
623 | static inline int __queue_kicked_iocb(struct kiocb *iocb) | |
624 | { | |
625 | struct kioctx *ctx = iocb->ki_ctx; | |
626 | ||
627 | assert_spin_locked(&ctx->ctx_lock); | |
628 | ||
629 | if (list_empty(&iocb->ki_run_list)) { | |
630 | list_add_tail(&iocb->ki_run_list, | |
631 | &ctx->run_list); | |
632 | return 1; | |
633 | } | |
634 | return 0; | |
635 | } | |
636 | ||
637 | /* aio_run_iocb | |
638 | * This is the core aio execution routine. It is | |
639 | * invoked both for initial i/o submission and | |
640 | * subsequent retries via the aio_kick_handler. | |
641 | * Expects to be invoked with iocb->ki_ctx->lock | |
642 | * already held. The lock is released and reacquired | |
643 | * as needed during processing. | |
644 | * | |
645 | * Calls the iocb retry method (already setup for the | |
646 | * iocb on initial submission) for operation specific | |
647 | * handling, but takes care of most of common retry | |
648 | * execution details for a given iocb. The retry method | |
649 | * needs to be non-blocking as far as possible, to avoid | |
650 | * holding up other iocbs waiting to be serviced by the | |
651 | * retry kernel thread. | |
652 | * | |
653 | * The trickier parts in this code have to do with | |
654 | * ensuring that only one retry instance is in progress | |
655 | * for a given iocb at any time. Providing that guarantee | |
656 | * simplifies the coding of individual aio operations as | |
657 | * it avoids various potential races. | |
658 | */ | |
659 | static ssize_t aio_run_iocb(struct kiocb *iocb) | |
660 | { | |
661 | struct kioctx *ctx = iocb->ki_ctx; | |
662 | ssize_t (*retry)(struct kiocb *); | |
663 | ssize_t ret; | |
664 | ||
665 | if (!(retry = iocb->ki_retry)) { | |
666 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); | |
667 | return 0; | |
668 | } | |
669 | ||
670 | /* | |
671 | * We don't want the next retry iteration for this | |
672 | * operation to start until this one has returned and | |
673 | * updated the iocb state. However, wait_queue functions | |
674 | * can trigger a kick_iocb from interrupt context in the | |
675 | * meantime, indicating that data is available for the next | |
676 | * iteration. We want to remember that and enable the | |
677 | * next retry iteration _after_ we are through with | |
678 | * this one. | |
679 | * | |
680 | * So, in order to be able to register a "kick", but | |
681 | * prevent it from being queued now, we clear the kick | |
682 | * flag, but make the kick code *think* that the iocb is | |
683 | * still on the run list until we are actually done. | |
684 | * When we are done with this iteration, we check if | |
685 | * the iocb was kicked in the meantime and if so, queue | |
686 | * it up afresh. | |
687 | */ | |
688 | ||
689 | kiocbClearKicked(iocb); | |
690 | ||
691 | /* | |
692 | * This is so that aio_complete knows it doesn't need to | |
693 | * pull the iocb off the run list (We can't just call | |
694 | * INIT_LIST_HEAD because we don't want a kick_iocb to | |
695 | * queue this on the run list yet) | |
696 | */ | |
697 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; | |
698 | spin_unlock_irq(&ctx->ctx_lock); | |
699 | ||
700 | /* Quit retrying if the i/o has been cancelled */ | |
701 | if (kiocbIsCancelled(iocb)) { | |
702 | ret = -EINTR; | |
703 | aio_complete(iocb, ret, 0); | |
704 | /* must not access the iocb after this */ | |
705 | goto out; | |
706 | } | |
707 | ||
708 | /* | |
709 | * Now we are all set to call the retry method in async | |
710 | * context. | |
711 | */ | |
712 | ret = retry(iocb); | |
713 | ||
714 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) | |
715 | aio_complete(iocb, ret, 0); | |
716 | out: | |
717 | spin_lock_irq(&ctx->ctx_lock); | |
718 | ||
719 | if (-EIOCBRETRY == ret) { | |
720 | /* | |
721 | * OK, now that we are done with this iteration | |
722 | * and know that there is more left to go, | |
723 | * this is where we let go so that a subsequent | |
724 | * "kick" can start the next iteration | |
725 | */ | |
726 | ||
727 | /* will make __queue_kicked_iocb succeed from here on */ | |
728 | INIT_LIST_HEAD(&iocb->ki_run_list); | |
729 | /* we must queue the next iteration ourselves, if it | |
730 | * has already been kicked */ | |
731 | if (kiocbIsKicked(iocb)) { | |
732 | __queue_kicked_iocb(iocb); | |
733 | ||
734 | /* | |
735 | * __queue_kicked_iocb will always return 1 here, because | |
736 | * iocb->ki_run_list is empty at this point so it should | |
737 | * be safe to unconditionally queue the context into the | |
738 | * work queue. | |
739 | */ | |
740 | aio_queue_work(ctx); | |
741 | } | |
742 | } | |
743 | return ret; | |
744 | } | |
745 | ||
746 | /* | |
747 | * __aio_run_iocbs: | |
748 | * Process all pending retries queued on the ioctx | |
749 | * run list. | |
750 | * Assumes it is operating within the aio issuer's mm | |
751 | * context. | |
752 | */ | |
753 | static int __aio_run_iocbs(struct kioctx *ctx) | |
754 | { | |
755 | struct kiocb *iocb; | |
756 | struct list_head run_list; | |
757 | ||
758 | assert_spin_locked(&ctx->ctx_lock); | |
759 | ||
760 | list_replace_init(&ctx->run_list, &run_list); | |
761 | while (!list_empty(&run_list)) { | |
762 | iocb = list_entry(run_list.next, struct kiocb, | |
763 | ki_run_list); | |
764 | list_del(&iocb->ki_run_list); | |
765 | /* | |
766 | * Hold an extra reference while retrying i/o. | |
767 | */ | |
768 | iocb->ki_users++; /* grab extra reference */ | |
769 | aio_run_iocb(iocb); | |
770 | __aio_put_req(ctx, iocb); | |
771 | } | |
772 | if (!list_empty(&ctx->run_list)) | |
773 | return 1; | |
774 | return 0; | |
775 | } | |
776 | ||
777 | static void aio_queue_work(struct kioctx * ctx) | |
778 | { | |
779 | unsigned long timeout; | |
780 | /* | |
781 | * if someone is waiting, get the work started right | |
782 | * away, otherwise, use a longer delay | |
783 | */ | |
784 | smp_mb(); | |
785 | if (waitqueue_active(&ctx->wait)) | |
786 | timeout = 1; | |
787 | else | |
788 | timeout = HZ/10; | |
789 | queue_delayed_work(aio_wq, &ctx->wq, timeout); | |
790 | } | |
791 | ||
792 | ||
793 | /* | |
794 | * aio_run_iocbs: | |
795 | * Process all pending retries queued on the ioctx | |
796 | * run list. | |
797 | * Assumes it is operating within the aio issuer's mm | |
798 | * context. | |
799 | */ | |
800 | static inline void aio_run_iocbs(struct kioctx *ctx) | |
801 | { | |
802 | int requeue; | |
803 | ||
804 | spin_lock_irq(&ctx->ctx_lock); | |
805 | ||
806 | requeue = __aio_run_iocbs(ctx); | |
807 | spin_unlock_irq(&ctx->ctx_lock); | |
808 | if (requeue) | |
809 | aio_queue_work(ctx); | |
810 | } | |
811 | ||
812 | /* | |
813 | * just like aio_run_iocbs, but keeps running them until | |
814 | * the list stays empty | |
815 | */ | |
816 | static inline void aio_run_all_iocbs(struct kioctx *ctx) | |
817 | { | |
818 | spin_lock_irq(&ctx->ctx_lock); | |
819 | while (__aio_run_iocbs(ctx)) | |
820 | ; | |
821 | spin_unlock_irq(&ctx->ctx_lock); | |
822 | } | |
823 | ||
824 | /* | |
825 | * aio_kick_handler: | |
826 | * Work queue handler triggered to process pending | |
827 | * retries on an ioctx. Takes on the aio issuer's | |
828 | * mm context before running the iocbs, so that | |
829 | * copy_xxx_user operates on the issuer's address | |
830 | * space. | |
831 | * Run on aiod's context. | |
832 | */ | |
833 | static void aio_kick_handler(struct work_struct *work) | |
834 | { | |
835 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); | |
836 | mm_segment_t oldfs = get_fs(); | |
837 | struct mm_struct *mm; | |
838 | int requeue; | |
839 | ||
840 | set_fs(USER_DS); | |
841 | use_mm(ctx->mm); | |
842 | spin_lock_irq(&ctx->ctx_lock); | |
843 | requeue =__aio_run_iocbs(ctx); | |
844 | mm = ctx->mm; | |
845 | spin_unlock_irq(&ctx->ctx_lock); | |
846 | unuse_mm(mm); | |
847 | set_fs(oldfs); | |
848 | /* | |
849 | * we're in a worker thread already, don't use queue_delayed_work, | |
850 | */ | |
851 | if (requeue) | |
852 | queue_delayed_work(aio_wq, &ctx->wq, 0); | |
853 | } | |
854 | ||
855 | ||
856 | /* | |
857 | * Called by kick_iocb to queue the kiocb for retry | |
858 | * and if required activate the aio work queue to process | |
859 | * it | |
860 | */ | |
861 | static void try_queue_kicked_iocb(struct kiocb *iocb) | |
862 | { | |
863 | struct kioctx *ctx = iocb->ki_ctx; | |
864 | unsigned long flags; | |
865 | int run = 0; | |
866 | ||
867 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
868 | /* set this inside the lock so that we can't race with aio_run_iocb() | |
869 | * testing it and putting the iocb on the run list under the lock */ | |
870 | if (!kiocbTryKick(iocb)) | |
871 | run = __queue_kicked_iocb(iocb); | |
872 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
873 | if (run) | |
874 | aio_queue_work(ctx); | |
875 | } | |
876 | ||
877 | /* | |
878 | * kick_iocb: | |
879 | * Called typically from a wait queue callback context | |
880 | * to trigger a retry of the iocb. | |
881 | * The retry is usually executed by aio workqueue | |
882 | * threads (See aio_kick_handler). | |
883 | */ | |
884 | void kick_iocb(struct kiocb *iocb) | |
885 | { | |
886 | /* sync iocbs are easy: they can only ever be executing from a | |
887 | * single context. */ | |
888 | if (is_sync_kiocb(iocb)) { | |
889 | kiocbSetKicked(iocb); | |
890 | wake_up_process(iocb->ki_obj.tsk); | |
891 | return; | |
892 | } | |
893 | ||
894 | try_queue_kicked_iocb(iocb); | |
895 | } | |
896 | EXPORT_SYMBOL(kick_iocb); | |
897 | ||
898 | /* aio_complete | |
899 | * Called when the io request on the given iocb is complete. | |
900 | * Returns true if this is the last user of the request. The | |
901 | * only other user of the request can be the cancellation code. | |
902 | */ | |
903 | int aio_complete(struct kiocb *iocb, long res, long res2) | |
904 | { | |
905 | struct kioctx *ctx = iocb->ki_ctx; | |
906 | struct aio_ring_info *info; | |
907 | struct aio_ring *ring; | |
908 | struct io_event *event; | |
909 | unsigned long flags; | |
910 | unsigned long tail; | |
911 | int ret; | |
912 | ||
913 | /* | |
914 | * Special case handling for sync iocbs: | |
915 | * - events go directly into the iocb for fast handling | |
916 | * - the sync task with the iocb in its stack holds the single iocb | |
917 | * ref, no other paths have a way to get another ref | |
918 | * - the sync task helpfully left a reference to itself in the iocb | |
919 | */ | |
920 | if (is_sync_kiocb(iocb)) { | |
921 | BUG_ON(iocb->ki_users != 1); | |
922 | iocb->ki_user_data = res; | |
923 | iocb->ki_users = 0; | |
924 | wake_up_process(iocb->ki_obj.tsk); | |
925 | return 1; | |
926 | } | |
927 | ||
928 | info = &ctx->ring_info; | |
929 | ||
930 | /* add a completion event to the ring buffer. | |
931 | * must be done holding ctx->ctx_lock to prevent | |
932 | * other code from messing with the tail | |
933 | * pointer since we might be called from irq | |
934 | * context. | |
935 | */ | |
936 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
937 | ||
938 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) | |
939 | list_del_init(&iocb->ki_run_list); | |
940 | ||
941 | /* | |
942 | * cancelled requests don't get events, userland was given one | |
943 | * when the event got cancelled. | |
944 | */ | |
945 | if (kiocbIsCancelled(iocb)) | |
946 | goto put_rq; | |
947 | ||
948 | ring = kmap_atomic(info->ring_pages[0], KM_IRQ1); | |
949 | ||
950 | tail = info->tail; | |
951 | event = aio_ring_event(info, tail, KM_IRQ0); | |
952 | if (++tail >= info->nr) | |
953 | tail = 0; | |
954 | ||
955 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; | |
956 | event->data = iocb->ki_user_data; | |
957 | event->res = res; | |
958 | event->res2 = res2; | |
959 | ||
960 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", | |
961 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, | |
962 | res, res2); | |
963 | ||
964 | /* after flagging the request as done, we | |
965 | * must never even look at it again | |
966 | */ | |
967 | smp_wmb(); /* make event visible before updating tail */ | |
968 | ||
969 | info->tail = tail; | |
970 | ring->tail = tail; | |
971 | ||
972 | put_aio_ring_event(event, KM_IRQ0); | |
973 | kunmap_atomic(ring, KM_IRQ1); | |
974 | ||
975 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); | |
976 | ||
977 | /* | |
978 | * Check if the user asked us to deliver the result through an | |
979 | * eventfd. The eventfd_signal() function is safe to be called | |
980 | * from IRQ context. | |
981 | */ | |
982 | if (iocb->ki_eventfd != NULL) | |
983 | eventfd_signal(iocb->ki_eventfd, 1); | |
984 | ||
985 | put_rq: | |
986 | /* everything turned out well, dispose of the aiocb. */ | |
987 | ret = __aio_put_req(ctx, iocb); | |
988 | ||
989 | /* | |
990 | * We have to order our ring_info tail store above and test | |
991 | * of the wait list below outside the wait lock. This is | |
992 | * like in wake_up_bit() where clearing a bit has to be | |
993 | * ordered with the unlocked test. | |
994 | */ | |
995 | smp_mb(); | |
996 | ||
997 | if (waitqueue_active(&ctx->wait)) | |
998 | wake_up(&ctx->wait); | |
999 | ||
1000 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
1001 | return ret; | |
1002 | } | |
1003 | EXPORT_SYMBOL(aio_complete); | |
1004 | ||
1005 | /* aio_read_evt | |
1006 | * Pull an event off of the ioctx's event ring. Returns the number of | |
1007 | * events fetched (0 or 1 ;-) | |
1008 | * FIXME: make this use cmpxchg. | |
1009 | * TODO: make the ringbuffer user mmap()able (requires FIXME). | |
1010 | */ | |
1011 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) | |
1012 | { | |
1013 | struct aio_ring_info *info = &ioctx->ring_info; | |
1014 | struct aio_ring *ring; | |
1015 | unsigned long head; | |
1016 | int ret = 0; | |
1017 | ||
1018 | ring = kmap_atomic(info->ring_pages[0], KM_USER0); | |
1019 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", | |
1020 | (unsigned long)ring->head, (unsigned long)ring->tail, | |
1021 | (unsigned long)ring->nr); | |
1022 | ||
1023 | if (ring->head == ring->tail) | |
1024 | goto out; | |
1025 | ||
1026 | spin_lock(&info->ring_lock); | |
1027 | ||
1028 | head = ring->head % info->nr; | |
1029 | if (head != ring->tail) { | |
1030 | struct io_event *evp = aio_ring_event(info, head, KM_USER1); | |
1031 | *ent = *evp; | |
1032 | head = (head + 1) % info->nr; | |
1033 | smp_mb(); /* finish reading the event before updatng the head */ | |
1034 | ring->head = head; | |
1035 | ret = 1; | |
1036 | put_aio_ring_event(evp, KM_USER1); | |
1037 | } | |
1038 | spin_unlock(&info->ring_lock); | |
1039 | ||
1040 | out: | |
1041 | kunmap_atomic(ring, KM_USER0); | |
1042 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, | |
1043 | (unsigned long)ring->head, (unsigned long)ring->tail); | |
1044 | return ret; | |
1045 | } | |
1046 | ||
1047 | struct aio_timeout { | |
1048 | struct timer_list timer; | |
1049 | int timed_out; | |
1050 | struct task_struct *p; | |
1051 | }; | |
1052 | ||
1053 | static void timeout_func(unsigned long data) | |
1054 | { | |
1055 | struct aio_timeout *to = (struct aio_timeout *)data; | |
1056 | ||
1057 | to->timed_out = 1; | |
1058 | wake_up_process(to->p); | |
1059 | } | |
1060 | ||
1061 | static inline void init_timeout(struct aio_timeout *to) | |
1062 | { | |
1063 | setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); | |
1064 | to->timed_out = 0; | |
1065 | to->p = current; | |
1066 | } | |
1067 | ||
1068 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, | |
1069 | const struct timespec *ts) | |
1070 | { | |
1071 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); | |
1072 | if (time_after(to->timer.expires, jiffies)) | |
1073 | add_timer(&to->timer); | |
1074 | else | |
1075 | to->timed_out = 1; | |
1076 | } | |
1077 | ||
1078 | static inline void clear_timeout(struct aio_timeout *to) | |
1079 | { | |
1080 | del_singleshot_timer_sync(&to->timer); | |
1081 | } | |
1082 | ||
1083 | static int read_events(struct kioctx *ctx, | |
1084 | long min_nr, long nr, | |
1085 | struct io_event __user *event, | |
1086 | struct timespec __user *timeout) | |
1087 | { | |
1088 | long start_jiffies = jiffies; | |
1089 | struct task_struct *tsk = current; | |
1090 | DECLARE_WAITQUEUE(wait, tsk); | |
1091 | int ret; | |
1092 | int i = 0; | |
1093 | struct io_event ent; | |
1094 | struct aio_timeout to; | |
1095 | int retry = 0; | |
1096 | ||
1097 | /* needed to zero any padding within an entry (there shouldn't be | |
1098 | * any, but C is fun! | |
1099 | */ | |
1100 | memset(&ent, 0, sizeof(ent)); | |
1101 | retry: | |
1102 | ret = 0; | |
1103 | while (likely(i < nr)) { | |
1104 | ret = aio_read_evt(ctx, &ent); | |
1105 | if (unlikely(ret <= 0)) | |
1106 | break; | |
1107 | ||
1108 | dprintk("read event: %Lx %Lx %Lx %Lx\n", | |
1109 | ent.data, ent.obj, ent.res, ent.res2); | |
1110 | ||
1111 | /* Could we split the check in two? */ | |
1112 | ret = -EFAULT; | |
1113 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { | |
1114 | dprintk("aio: lost an event due to EFAULT.\n"); | |
1115 | break; | |
1116 | } | |
1117 | ret = 0; | |
1118 | ||
1119 | /* Good, event copied to userland, update counts. */ | |
1120 | event ++; | |
1121 | i ++; | |
1122 | } | |
1123 | ||
1124 | if (min_nr <= i) | |
1125 | return i; | |
1126 | if (ret) | |
1127 | return ret; | |
1128 | ||
1129 | /* End fast path */ | |
1130 | ||
1131 | /* racey check, but it gets redone */ | |
1132 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { | |
1133 | retry = 1; | |
1134 | aio_run_all_iocbs(ctx); | |
1135 | goto retry; | |
1136 | } | |
1137 | ||
1138 | init_timeout(&to); | |
1139 | if (timeout) { | |
1140 | struct timespec ts; | |
1141 | ret = -EFAULT; | |
1142 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) | |
1143 | goto out; | |
1144 | ||
1145 | set_timeout(start_jiffies, &to, &ts); | |
1146 | } | |
1147 | ||
1148 | while (likely(i < nr)) { | |
1149 | add_wait_queue_exclusive(&ctx->wait, &wait); | |
1150 | do { | |
1151 | set_task_state(tsk, TASK_INTERRUPTIBLE); | |
1152 | ret = aio_read_evt(ctx, &ent); | |
1153 | if (ret) | |
1154 | break; | |
1155 | if (min_nr <= i) | |
1156 | break; | |
1157 | if (unlikely(ctx->dead)) { | |
1158 | ret = -EINVAL; | |
1159 | break; | |
1160 | } | |
1161 | if (to.timed_out) /* Only check after read evt */ | |
1162 | break; | |
1163 | /* Try to only show up in io wait if there are ops | |
1164 | * in flight */ | |
1165 | if (ctx->reqs_active) | |
1166 | io_schedule(); | |
1167 | else | |
1168 | schedule(); | |
1169 | if (signal_pending(tsk)) { | |
1170 | ret = -EINTR; | |
1171 | break; | |
1172 | } | |
1173 | /*ret = aio_read_evt(ctx, &ent);*/ | |
1174 | } while (1) ; | |
1175 | ||
1176 | set_task_state(tsk, TASK_RUNNING); | |
1177 | remove_wait_queue(&ctx->wait, &wait); | |
1178 | ||
1179 | if (unlikely(ret <= 0)) | |
1180 | break; | |
1181 | ||
1182 | ret = -EFAULT; | |
1183 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { | |
1184 | dprintk("aio: lost an event due to EFAULT.\n"); | |
1185 | break; | |
1186 | } | |
1187 | ||
1188 | /* Good, event copied to userland, update counts. */ | |
1189 | event ++; | |
1190 | i ++; | |
1191 | } | |
1192 | ||
1193 | if (timeout) | |
1194 | clear_timeout(&to); | |
1195 | out: | |
1196 | destroy_timer_on_stack(&to.timer); | |
1197 | return i ? i : ret; | |
1198 | } | |
1199 | ||
1200 | /* Take an ioctx and remove it from the list of ioctx's. Protects | |
1201 | * against races with itself via ->dead. | |
1202 | */ | |
1203 | static void io_destroy(struct kioctx *ioctx) | |
1204 | { | |
1205 | struct mm_struct *mm = current->mm; | |
1206 | int was_dead; | |
1207 | ||
1208 | /* delete the entry from the list is someone else hasn't already */ | |
1209 | spin_lock(&mm->ioctx_lock); | |
1210 | was_dead = ioctx->dead; | |
1211 | ioctx->dead = 1; | |
1212 | hlist_del_rcu(&ioctx->list); | |
1213 | spin_unlock(&mm->ioctx_lock); | |
1214 | ||
1215 | dprintk("aio_release(%p)\n", ioctx); | |
1216 | if (likely(!was_dead)) | |
1217 | put_ioctx(ioctx); /* twice for the list */ | |
1218 | ||
1219 | aio_cancel_all(ioctx); | |
1220 | wait_for_all_aios(ioctx); | |
1221 | ||
1222 | /* | |
1223 | * Wake up any waiters. The setting of ctx->dead must be seen | |
1224 | * by other CPUs at this point. Right now, we rely on the | |
1225 | * locking done by the above calls to ensure this consistency. | |
1226 | */ | |
1227 | wake_up(&ioctx->wait); | |
1228 | put_ioctx(ioctx); /* once for the lookup */ | |
1229 | } | |
1230 | ||
1231 | /* sys_io_setup: | |
1232 | * Create an aio_context capable of receiving at least nr_events. | |
1233 | * ctxp must not point to an aio_context that already exists, and | |
1234 | * must be initialized to 0 prior to the call. On successful | |
1235 | * creation of the aio_context, *ctxp is filled in with the resulting | |
1236 | * handle. May fail with -EINVAL if *ctxp is not initialized, | |
1237 | * if the specified nr_events exceeds internal limits. May fail | |
1238 | * with -EAGAIN if the specified nr_events exceeds the user's limit | |
1239 | * of available events. May fail with -ENOMEM if insufficient kernel | |
1240 | * resources are available. May fail with -EFAULT if an invalid | |
1241 | * pointer is passed for ctxp. Will fail with -ENOSYS if not | |
1242 | * implemented. | |
1243 | */ | |
1244 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) | |
1245 | { | |
1246 | struct kioctx *ioctx = NULL; | |
1247 | unsigned long ctx; | |
1248 | long ret; | |
1249 | ||
1250 | ret = get_user(ctx, ctxp); | |
1251 | if (unlikely(ret)) | |
1252 | goto out; | |
1253 | ||
1254 | ret = -EINVAL; | |
1255 | if (unlikely(ctx || nr_events == 0)) { | |
1256 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", | |
1257 | ctx, nr_events); | |
1258 | goto out; | |
1259 | } | |
1260 | ||
1261 | ioctx = ioctx_alloc(nr_events); | |
1262 | ret = PTR_ERR(ioctx); | |
1263 | if (!IS_ERR(ioctx)) { | |
1264 | ret = put_user(ioctx->user_id, ctxp); | |
1265 | if (!ret) | |
1266 | return 0; | |
1267 | ||
1268 | get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */ | |
1269 | io_destroy(ioctx); | |
1270 | } | |
1271 | ||
1272 | out: | |
1273 | return ret; | |
1274 | } | |
1275 | ||
1276 | /* sys_io_destroy: | |
1277 | * Destroy the aio_context specified. May cancel any outstanding | |
1278 | * AIOs and block on completion. Will fail with -ENOSYS if not | |
1279 | * implemented. May fail with -EFAULT if the context pointed to | |
1280 | * is invalid. | |
1281 | */ | |
1282 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) | |
1283 | { | |
1284 | struct kioctx *ioctx = lookup_ioctx(ctx); | |
1285 | if (likely(NULL != ioctx)) { | |
1286 | io_destroy(ioctx); | |
1287 | return 0; | |
1288 | } | |
1289 | pr_debug("EINVAL: io_destroy: invalid context id\n"); | |
1290 | return -EINVAL; | |
1291 | } | |
1292 | ||
1293 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) | |
1294 | { | |
1295 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; | |
1296 | ||
1297 | BUG_ON(ret <= 0); | |
1298 | ||
1299 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { | |
1300 | ssize_t this = min((ssize_t)iov->iov_len, ret); | |
1301 | iov->iov_base += this; | |
1302 | iov->iov_len -= this; | |
1303 | iocb->ki_left -= this; | |
1304 | ret -= this; | |
1305 | if (iov->iov_len == 0) { | |
1306 | iocb->ki_cur_seg++; | |
1307 | iov++; | |
1308 | } | |
1309 | } | |
1310 | ||
1311 | /* the caller should not have done more io than what fit in | |
1312 | * the remaining iovecs */ | |
1313 | BUG_ON(ret > 0 && iocb->ki_left == 0); | |
1314 | } | |
1315 | ||
1316 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) | |
1317 | { | |
1318 | struct file *file = iocb->ki_filp; | |
1319 | struct address_space *mapping = file->f_mapping; | |
1320 | struct inode *inode = mapping->host; | |
1321 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, | |
1322 | unsigned long, loff_t); | |
1323 | ssize_t ret = 0; | |
1324 | unsigned short opcode; | |
1325 | ||
1326 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || | |
1327 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { | |
1328 | rw_op = file->f_op->aio_read; | |
1329 | opcode = IOCB_CMD_PREADV; | |
1330 | } else { | |
1331 | rw_op = file->f_op->aio_write; | |
1332 | opcode = IOCB_CMD_PWRITEV; | |
1333 | } | |
1334 | ||
1335 | /* This matches the pread()/pwrite() logic */ | |
1336 | if (iocb->ki_pos < 0) | |
1337 | return -EINVAL; | |
1338 | ||
1339 | do { | |
1340 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], | |
1341 | iocb->ki_nr_segs - iocb->ki_cur_seg, | |
1342 | iocb->ki_pos); | |
1343 | if (ret > 0) | |
1344 | aio_advance_iovec(iocb, ret); | |
1345 | ||
1346 | /* retry all partial writes. retry partial reads as long as its a | |
1347 | * regular file. */ | |
1348 | } while (ret > 0 && iocb->ki_left > 0 && | |
1349 | (opcode == IOCB_CMD_PWRITEV || | |
1350 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); | |
1351 | ||
1352 | /* This means we must have transferred all that we could */ | |
1353 | /* No need to retry anymore */ | |
1354 | if ((ret == 0) || (iocb->ki_left == 0)) | |
1355 | ret = iocb->ki_nbytes - iocb->ki_left; | |
1356 | ||
1357 | /* If we managed to write some out we return that, rather than | |
1358 | * the eventual error. */ | |
1359 | if (opcode == IOCB_CMD_PWRITEV | |
1360 | && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY | |
1361 | && iocb->ki_nbytes - iocb->ki_left) | |
1362 | ret = iocb->ki_nbytes - iocb->ki_left; | |
1363 | ||
1364 | return ret; | |
1365 | } | |
1366 | ||
1367 | static ssize_t aio_fdsync(struct kiocb *iocb) | |
1368 | { | |
1369 | struct file *file = iocb->ki_filp; | |
1370 | ssize_t ret = -EINVAL; | |
1371 | ||
1372 | if (file->f_op->aio_fsync) | |
1373 | ret = file->f_op->aio_fsync(iocb, 1); | |
1374 | return ret; | |
1375 | } | |
1376 | ||
1377 | static ssize_t aio_fsync(struct kiocb *iocb) | |
1378 | { | |
1379 | struct file *file = iocb->ki_filp; | |
1380 | ssize_t ret = -EINVAL; | |
1381 | ||
1382 | if (file->f_op->aio_fsync) | |
1383 | ret = file->f_op->aio_fsync(iocb, 0); | |
1384 | return ret; | |
1385 | } | |
1386 | ||
1387 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb) | |
1388 | { | |
1389 | ssize_t ret; | |
1390 | ||
1391 | ret = rw_copy_check_uvector(type, (struct iovec __user *)kiocb->ki_buf, | |
1392 | kiocb->ki_nbytes, 1, | |
1393 | &kiocb->ki_inline_vec, &kiocb->ki_iovec); | |
1394 | if (ret < 0) | |
1395 | goto out; | |
1396 | ||
1397 | kiocb->ki_nr_segs = kiocb->ki_nbytes; | |
1398 | kiocb->ki_cur_seg = 0; | |
1399 | /* ki_nbytes/left now reflect bytes instead of segs */ | |
1400 | kiocb->ki_nbytes = ret; | |
1401 | kiocb->ki_left = ret; | |
1402 | ||
1403 | ret = 0; | |
1404 | out: | |
1405 | return ret; | |
1406 | } | |
1407 | ||
1408 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb) | |
1409 | { | |
1410 | kiocb->ki_iovec = &kiocb->ki_inline_vec; | |
1411 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; | |
1412 | kiocb->ki_iovec->iov_len = kiocb->ki_left; | |
1413 | kiocb->ki_nr_segs = 1; | |
1414 | kiocb->ki_cur_seg = 0; | |
1415 | return 0; | |
1416 | } | |
1417 | ||
1418 | /* | |
1419 | * aio_setup_iocb: | |
1420 | * Performs the initial checks and aio retry method | |
1421 | * setup for the kiocb at the time of io submission. | |
1422 | */ | |
1423 | static ssize_t aio_setup_iocb(struct kiocb *kiocb) | |
1424 | { | |
1425 | struct file *file = kiocb->ki_filp; | |
1426 | ssize_t ret = 0; | |
1427 | ||
1428 | switch (kiocb->ki_opcode) { | |
1429 | case IOCB_CMD_PREAD: | |
1430 | ret = -EBADF; | |
1431 | if (unlikely(!(file->f_mode & FMODE_READ))) | |
1432 | break; | |
1433 | ret = -EFAULT; | |
1434 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, | |
1435 | kiocb->ki_left))) | |
1436 | break; | |
1437 | ret = security_file_permission(file, MAY_READ); | |
1438 | if (unlikely(ret)) | |
1439 | break; | |
1440 | ret = aio_setup_single_vector(kiocb); | |
1441 | if (ret) | |
1442 | break; | |
1443 | ret = -EINVAL; | |
1444 | if (file->f_op->aio_read) | |
1445 | kiocb->ki_retry = aio_rw_vect_retry; | |
1446 | break; | |
1447 | case IOCB_CMD_PWRITE: | |
1448 | ret = -EBADF; | |
1449 | if (unlikely(!(file->f_mode & FMODE_WRITE))) | |
1450 | break; | |
1451 | ret = -EFAULT; | |
1452 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, | |
1453 | kiocb->ki_left))) | |
1454 | break; | |
1455 | ret = security_file_permission(file, MAY_WRITE); | |
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_write) | |
1463 | kiocb->ki_retry = aio_rw_vect_retry; | |
1464 | break; | |
1465 | case IOCB_CMD_PREADV: | |
1466 | ret = -EBADF; | |
1467 | if (unlikely(!(file->f_mode & FMODE_READ))) | |
1468 | break; | |
1469 | ret = security_file_permission(file, MAY_READ); | |
1470 | if (unlikely(ret)) | |
1471 | break; | |
1472 | ret = aio_setup_vectored_rw(READ, kiocb); | |
1473 | if (ret) | |
1474 | break; | |
1475 | ret = -EINVAL; | |
1476 | if (file->f_op->aio_read) | |
1477 | kiocb->ki_retry = aio_rw_vect_retry; | |
1478 | break; | |
1479 | case IOCB_CMD_PWRITEV: | |
1480 | ret = -EBADF; | |
1481 | if (unlikely(!(file->f_mode & FMODE_WRITE))) | |
1482 | break; | |
1483 | ret = security_file_permission(file, MAY_WRITE); | |
1484 | if (unlikely(ret)) | |
1485 | break; | |
1486 | ret = aio_setup_vectored_rw(WRITE, kiocb); | |
1487 | if (ret) | |
1488 | break; | |
1489 | ret = -EINVAL; | |
1490 | if (file->f_op->aio_write) | |
1491 | kiocb->ki_retry = aio_rw_vect_retry; | |
1492 | break; | |
1493 | case IOCB_CMD_FDSYNC: | |
1494 | ret = -EINVAL; | |
1495 | if (file->f_op->aio_fsync) | |
1496 | kiocb->ki_retry = aio_fdsync; | |
1497 | break; | |
1498 | case IOCB_CMD_FSYNC: | |
1499 | ret = -EINVAL; | |
1500 | if (file->f_op->aio_fsync) | |
1501 | kiocb->ki_retry = aio_fsync; | |
1502 | break; | |
1503 | default: | |
1504 | dprintk("EINVAL: io_submit: no operation provided\n"); | |
1505 | ret = -EINVAL; | |
1506 | } | |
1507 | ||
1508 | if (!kiocb->ki_retry) | |
1509 | return ret; | |
1510 | ||
1511 | return 0; | |
1512 | } | |
1513 | ||
1514 | static void aio_batch_add(struct address_space *mapping, | |
1515 | struct hlist_head *batch_hash) | |
1516 | { | |
1517 | struct aio_batch_entry *abe; | |
1518 | struct hlist_node *pos; | |
1519 | unsigned bucket; | |
1520 | ||
1521 | bucket = hash_ptr(mapping, AIO_BATCH_HASH_BITS); | |
1522 | hlist_for_each_entry(abe, pos, &batch_hash[bucket], list) { | |
1523 | if (abe->mapping == mapping) | |
1524 | return; | |
1525 | } | |
1526 | ||
1527 | abe = mempool_alloc(abe_pool, GFP_KERNEL); | |
1528 | BUG_ON(!igrab(mapping->host)); | |
1529 | abe->mapping = mapping; | |
1530 | hlist_add_head(&abe->list, &batch_hash[bucket]); | |
1531 | return; | |
1532 | } | |
1533 | ||
1534 | static void aio_batch_free(struct hlist_head *batch_hash) | |
1535 | { | |
1536 | struct aio_batch_entry *abe; | |
1537 | struct hlist_node *pos, *n; | |
1538 | int i; | |
1539 | ||
1540 | for (i = 0; i < AIO_BATCH_HASH_SIZE; i++) { | |
1541 | hlist_for_each_entry_safe(abe, pos, n, &batch_hash[i], list) { | |
1542 | blk_run_address_space(abe->mapping); | |
1543 | iput(abe->mapping->host); | |
1544 | hlist_del(&abe->list); | |
1545 | mempool_free(abe, abe_pool); | |
1546 | } | |
1547 | } | |
1548 | } | |
1549 | ||
1550 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, | |
1551 | struct iocb *iocb, struct hlist_head *batch_hash) | |
1552 | { | |
1553 | struct kiocb *req; | |
1554 | struct file *file; | |
1555 | ssize_t ret; | |
1556 | ||
1557 | /* enforce forwards compatibility on users */ | |
1558 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { | |
1559 | pr_debug("EINVAL: io_submit: reserve field set\n"); | |
1560 | return -EINVAL; | |
1561 | } | |
1562 | ||
1563 | /* prevent overflows */ | |
1564 | if (unlikely( | |
1565 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || | |
1566 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || | |
1567 | ((ssize_t)iocb->aio_nbytes < 0) | |
1568 | )) { | |
1569 | pr_debug("EINVAL: io_submit: overflow check\n"); | |
1570 | return -EINVAL; | |
1571 | } | |
1572 | ||
1573 | file = fget(iocb->aio_fildes); | |
1574 | if (unlikely(!file)) | |
1575 | return -EBADF; | |
1576 | ||
1577 | req = aio_get_req(ctx); /* returns with 2 references to req */ | |
1578 | if (unlikely(!req)) { | |
1579 | fput(file); | |
1580 | return -EAGAIN; | |
1581 | } | |
1582 | req->ki_filp = file; | |
1583 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { | |
1584 | /* | |
1585 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an | |
1586 | * instance of the file* now. The file descriptor must be | |
1587 | * an eventfd() fd, and will be signaled for each completed | |
1588 | * event using the eventfd_signal() function. | |
1589 | */ | |
1590 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); | |
1591 | if (IS_ERR(req->ki_eventfd)) { | |
1592 | ret = PTR_ERR(req->ki_eventfd); | |
1593 | req->ki_eventfd = NULL; | |
1594 | goto out_put_req; | |
1595 | } | |
1596 | } | |
1597 | ||
1598 | ret = put_user(req->ki_key, &user_iocb->aio_key); | |
1599 | if (unlikely(ret)) { | |
1600 | dprintk("EFAULT: aio_key\n"); | |
1601 | goto out_put_req; | |
1602 | } | |
1603 | ||
1604 | req->ki_obj.user = user_iocb; | |
1605 | req->ki_user_data = iocb->aio_data; | |
1606 | req->ki_pos = iocb->aio_offset; | |
1607 | ||
1608 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; | |
1609 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; | |
1610 | req->ki_opcode = iocb->aio_lio_opcode; | |
1611 | ||
1612 | ret = aio_setup_iocb(req); | |
1613 | ||
1614 | if (ret) | |
1615 | goto out_put_req; | |
1616 | ||
1617 | spin_lock_irq(&ctx->ctx_lock); | |
1618 | aio_run_iocb(req); | |
1619 | if (!list_empty(&ctx->run_list)) { | |
1620 | /* drain the run list */ | |
1621 | while (__aio_run_iocbs(ctx)) | |
1622 | ; | |
1623 | } | |
1624 | spin_unlock_irq(&ctx->ctx_lock); | |
1625 | if (req->ki_opcode == IOCB_CMD_PREAD || | |
1626 | req->ki_opcode == IOCB_CMD_PREADV || | |
1627 | req->ki_opcode == IOCB_CMD_PWRITE || | |
1628 | req->ki_opcode == IOCB_CMD_PWRITEV) | |
1629 | aio_batch_add(file->f_mapping, batch_hash); | |
1630 | ||
1631 | aio_put_req(req); /* drop extra ref to req */ | |
1632 | return 0; | |
1633 | ||
1634 | out_put_req: | |
1635 | aio_put_req(req); /* drop extra ref to req */ | |
1636 | aio_put_req(req); /* drop i/o ref to req */ | |
1637 | return ret; | |
1638 | } | |
1639 | ||
1640 | /* sys_io_submit: | |
1641 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns | |
1642 | * the number of iocbs queued. May return -EINVAL if the aio_context | |
1643 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at | |
1644 | * *iocbpp[0] is not properly initialized, if the operation specified | |
1645 | * is invalid for the file descriptor in the iocb. May fail with | |
1646 | * -EFAULT if any of the data structures point to invalid data. May | |
1647 | * fail with -EBADF if the file descriptor specified in the first | |
1648 | * iocb is invalid. May fail with -EAGAIN if insufficient resources | |
1649 | * are available to queue any iocbs. Will return 0 if nr is 0. Will | |
1650 | * fail with -ENOSYS if not implemented. | |
1651 | */ | |
1652 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, | |
1653 | struct iocb __user * __user *, iocbpp) | |
1654 | { | |
1655 | struct kioctx *ctx; | |
1656 | long ret = 0; | |
1657 | int i; | |
1658 | struct hlist_head batch_hash[AIO_BATCH_HASH_SIZE] = { { 0, }, }; | |
1659 | ||
1660 | if (unlikely(nr < 0)) | |
1661 | return -EINVAL; | |
1662 | ||
1663 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) | |
1664 | return -EFAULT; | |
1665 | ||
1666 | ctx = lookup_ioctx(ctx_id); | |
1667 | if (unlikely(!ctx)) { | |
1668 | pr_debug("EINVAL: io_submit: invalid context id\n"); | |
1669 | return -EINVAL; | |
1670 | } | |
1671 | ||
1672 | /* | |
1673 | * AKPM: should this return a partial result if some of the IOs were | |
1674 | * successfully submitted? | |
1675 | */ | |
1676 | for (i=0; i<nr; i++) { | |
1677 | struct iocb __user *user_iocb; | |
1678 | struct iocb tmp; | |
1679 | ||
1680 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { | |
1681 | ret = -EFAULT; | |
1682 | break; | |
1683 | } | |
1684 | ||
1685 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { | |
1686 | ret = -EFAULT; | |
1687 | break; | |
1688 | } | |
1689 | ||
1690 | ret = io_submit_one(ctx, user_iocb, &tmp, batch_hash); | |
1691 | if (ret) | |
1692 | break; | |
1693 | } | |
1694 | aio_batch_free(batch_hash); | |
1695 | ||
1696 | put_ioctx(ctx); | |
1697 | return i ? i : ret; | |
1698 | } | |
1699 | ||
1700 | /* lookup_kiocb | |
1701 | * Finds a given iocb for cancellation. | |
1702 | */ | |
1703 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, | |
1704 | u32 key) | |
1705 | { | |
1706 | struct list_head *pos; | |
1707 | ||
1708 | assert_spin_locked(&ctx->ctx_lock); | |
1709 | ||
1710 | /* TODO: use a hash or array, this sucks. */ | |
1711 | list_for_each(pos, &ctx->active_reqs) { | |
1712 | struct kiocb *kiocb = list_kiocb(pos); | |
1713 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) | |
1714 | return kiocb; | |
1715 | } | |
1716 | return NULL; | |
1717 | } | |
1718 | ||
1719 | /* sys_io_cancel: | |
1720 | * Attempts to cancel an iocb previously passed to io_submit. If | |
1721 | * the operation is successfully cancelled, the resulting event is | |
1722 | * copied into the memory pointed to by result without being placed | |
1723 | * into the completion queue and 0 is returned. May fail with | |
1724 | * -EFAULT if any of the data structures pointed to are invalid. | |
1725 | * May fail with -EINVAL if aio_context specified by ctx_id is | |
1726 | * invalid. May fail with -EAGAIN if the iocb specified was not | |
1727 | * cancelled. Will fail with -ENOSYS if not implemented. | |
1728 | */ | |
1729 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, | |
1730 | struct io_event __user *, result) | |
1731 | { | |
1732 | int (*cancel)(struct kiocb *iocb, struct io_event *res); | |
1733 | struct kioctx *ctx; | |
1734 | struct kiocb *kiocb; | |
1735 | u32 key; | |
1736 | int ret; | |
1737 | ||
1738 | ret = get_user(key, &iocb->aio_key); | |
1739 | if (unlikely(ret)) | |
1740 | return -EFAULT; | |
1741 | ||
1742 | ctx = lookup_ioctx(ctx_id); | |
1743 | if (unlikely(!ctx)) | |
1744 | return -EINVAL; | |
1745 | ||
1746 | spin_lock_irq(&ctx->ctx_lock); | |
1747 | ret = -EAGAIN; | |
1748 | kiocb = lookup_kiocb(ctx, iocb, key); | |
1749 | if (kiocb && kiocb->ki_cancel) { | |
1750 | cancel = kiocb->ki_cancel; | |
1751 | kiocb->ki_users ++; | |
1752 | kiocbSetCancelled(kiocb); | |
1753 | } else | |
1754 | cancel = NULL; | |
1755 | spin_unlock_irq(&ctx->ctx_lock); | |
1756 | ||
1757 | if (NULL != cancel) { | |
1758 | struct io_event tmp; | |
1759 | pr_debug("calling cancel\n"); | |
1760 | memset(&tmp, 0, sizeof(tmp)); | |
1761 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; | |
1762 | tmp.data = kiocb->ki_user_data; | |
1763 | ret = cancel(kiocb, &tmp); | |
1764 | if (!ret) { | |
1765 | /* Cancellation succeeded -- copy the result | |
1766 | * into the user's buffer. | |
1767 | */ | |
1768 | if (copy_to_user(result, &tmp, sizeof(tmp))) | |
1769 | ret = -EFAULT; | |
1770 | } | |
1771 | } else | |
1772 | ret = -EINVAL; | |
1773 | ||
1774 | put_ioctx(ctx); | |
1775 | ||
1776 | return ret; | |
1777 | } | |
1778 | ||
1779 | /* io_getevents: | |
1780 | * Attempts to read at least min_nr events and up to nr events from | |
1781 | * the completion queue for the aio_context specified by ctx_id. May | |
1782 | * fail with -EINVAL if ctx_id is invalid, if min_nr is out of range, | |
1783 | * if nr is out of range, if when is out of range. May fail with | |
1784 | * -EFAULT if any of the memory specified to is invalid. May return | |
1785 | * 0 or < min_nr if no events are available and the timeout specified | |
1786 | * by when has elapsed, where when == NULL specifies an infinite | |
1787 | * timeout. Note that the timeout pointed to by when is relative and | |
1788 | * will be updated if not NULL and the operation blocks. Will fail | |
1789 | * with -ENOSYS if not implemented. | |
1790 | */ | |
1791 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, | |
1792 | long, min_nr, | |
1793 | long, nr, | |
1794 | struct io_event __user *, events, | |
1795 | struct timespec __user *, timeout) | |
1796 | { | |
1797 | struct kioctx *ioctx = lookup_ioctx(ctx_id); | |
1798 | long ret = -EINVAL; | |
1799 | ||
1800 | if (likely(ioctx)) { | |
1801 | if (likely(min_nr <= nr && min_nr >= 0 && nr >= 0)) | |
1802 | ret = read_events(ioctx, min_nr, nr, events, timeout); | |
1803 | put_ioctx(ioctx); | |
1804 | } | |
1805 | ||
1806 | asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); | |
1807 | return ret; | |
1808 | } |