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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/export.h> | |
17 | #include <linux/syscalls.h> | |
18 | #include <linux/backing-dev.h> | |
19 | #include <linux/uio.h> | |
20 | ||
21 | #define DEBUG 0 | |
22 | ||
23 | #include <linux/sched.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/file.h> | |
26 | #include <linux/mm.h> | |
27 | #include <linux/mman.h> | |
28 | #include <linux/mmu_context.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/timer.h> | |
31 | #include <linux/aio.h> | |
32 | #include <linux/highmem.h> | |
33 | #include <linux/workqueue.h> | |
34 | #include <linux/security.h> | |
35 | #include <linux/eventfd.h> | |
36 | #include <linux/blkdev.h> | |
37 | #include <linux/compat.h> | |
38 | ||
39 | #include <asm/kmap_types.h> | |
40 | #include <asm/uaccess.h> | |
41 | ||
42 | #if DEBUG > 1 | |
43 | #define dprintk printk | |
44 | #else | |
45 | #define dprintk(x...) do { ; } while (0) | |
46 | #endif | |
47 | ||
48 | /*------ sysctl variables----*/ | |
49 | static DEFINE_SPINLOCK(aio_nr_lock); | |
50 | unsigned long aio_nr; /* current system wide number of aio requests */ | |
51 | unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ | |
52 | /*----end sysctl variables---*/ | |
53 | ||
54 | static struct kmem_cache *kiocb_cachep; | |
55 | static struct kmem_cache *kioctx_cachep; | |
56 | ||
57 | static struct workqueue_struct *aio_wq; | |
58 | ||
59 | /* 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 | BUG_ON(ctx->mm != current->mm); | |
97 | vm_munmap(info->mmap_base, info->mmap_size); | |
98 | } | |
99 | ||
100 | if (info->ring_pages && info->ring_pages != info->internal_pages) | |
101 | kfree(info->ring_pages); | |
102 | info->ring_pages = NULL; | |
103 | info->nr = 0; | |
104 | } | |
105 | ||
106 | static int aio_setup_ring(struct kioctx *ctx) | |
107 | { | |
108 | struct aio_ring *ring; | |
109 | struct aio_ring_info *info = &ctx->ring_info; | |
110 | unsigned nr_events = ctx->max_reqs; | |
111 | unsigned long size; | |
112 | int nr_pages; | |
113 | ||
114 | /* Compensate for the ring buffer's head/tail overlap entry */ | |
115 | nr_events += 2; /* 1 is required, 2 for good luck */ | |
116 | ||
117 | size = sizeof(struct aio_ring); | |
118 | size += sizeof(struct io_event) * nr_events; | |
119 | nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT; | |
120 | ||
121 | if (nr_pages < 0) | |
122 | return -EINVAL; | |
123 | ||
124 | nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event); | |
125 | ||
126 | info->nr = 0; | |
127 | info->ring_pages = info->internal_pages; | |
128 | if (nr_pages > AIO_RING_PAGES) { | |
129 | info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL); | |
130 | if (!info->ring_pages) | |
131 | return -ENOMEM; | |
132 | } | |
133 | ||
134 | info->mmap_size = nr_pages * PAGE_SIZE; | |
135 | dprintk("attempting mmap of %lu bytes\n", info->mmap_size); | |
136 | down_write(&ctx->mm->mmap_sem); | |
137 | info->mmap_base = do_mmap(NULL, 0, info->mmap_size, | |
138 | PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, | |
139 | 0); | |
140 | if (IS_ERR((void *)info->mmap_base)) { | |
141 | up_write(&ctx->mm->mmap_sem); | |
142 | info->mmap_size = 0; | |
143 | aio_free_ring(ctx); | |
144 | return -EAGAIN; | |
145 | } | |
146 | ||
147 | dprintk("mmap address: 0x%08lx\n", info->mmap_base); | |
148 | info->nr_pages = get_user_pages(current, ctx->mm, | |
149 | info->mmap_base, nr_pages, | |
150 | 1, 0, info->ring_pages, NULL); | |
151 | up_write(&ctx->mm->mmap_sem); | |
152 | ||
153 | if (unlikely(info->nr_pages != nr_pages)) { | |
154 | aio_free_ring(ctx); | |
155 | return -EAGAIN; | |
156 | } | |
157 | ||
158 | ctx->user_id = info->mmap_base; | |
159 | ||
160 | info->nr = nr_events; /* trusted copy */ | |
161 | ||
162 | ring = kmap_atomic(info->ring_pages[0]); | |
163 | ring->nr = nr_events; /* user copy */ | |
164 | ring->id = ctx->user_id; | |
165 | ring->head = ring->tail = 0; | |
166 | ring->magic = AIO_RING_MAGIC; | |
167 | ring->compat_features = AIO_RING_COMPAT_FEATURES; | |
168 | ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; | |
169 | ring->header_length = sizeof(struct aio_ring); | |
170 | kunmap_atomic(ring); | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
175 | ||
176 | /* aio_ring_event: returns a pointer to the event at the given index from | |
177 | * kmap_atomic(). Release the pointer with put_aio_ring_event(); | |
178 | */ | |
179 | #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) | |
180 | #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) | |
181 | #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) | |
182 | ||
183 | #define aio_ring_event(info, nr) ({ \ | |
184 | unsigned pos = (nr) + AIO_EVENTS_OFFSET; \ | |
185 | struct io_event *__event; \ | |
186 | __event = kmap_atomic( \ | |
187 | (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \ | |
188 | __event += pos % AIO_EVENTS_PER_PAGE; \ | |
189 | __event; \ | |
190 | }) | |
191 | ||
192 | #define put_aio_ring_event(event) do { \ | |
193 | struct io_event *__event = (event); \ | |
194 | (void)__event; \ | |
195 | kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \ | |
196 | } while(0) | |
197 | ||
198 | static void ctx_rcu_free(struct rcu_head *head) | |
199 | { | |
200 | struct kioctx *ctx = container_of(head, struct kioctx, rcu_head); | |
201 | kmem_cache_free(kioctx_cachep, ctx); | |
202 | } | |
203 | ||
204 | /* __put_ioctx | |
205 | * Called when the last user of an aio context has gone away, | |
206 | * and the struct needs to be freed. | |
207 | */ | |
208 | static void __put_ioctx(struct kioctx *ctx) | |
209 | { | |
210 | unsigned nr_events = ctx->max_reqs; | |
211 | BUG_ON(ctx->reqs_active); | |
212 | ||
213 | cancel_delayed_work_sync(&ctx->wq); | |
214 | aio_free_ring(ctx); | |
215 | mmdrop(ctx->mm); | |
216 | ctx->mm = NULL; | |
217 | if (nr_events) { | |
218 | spin_lock(&aio_nr_lock); | |
219 | BUG_ON(aio_nr - nr_events > aio_nr); | |
220 | aio_nr -= nr_events; | |
221 | spin_unlock(&aio_nr_lock); | |
222 | } | |
223 | pr_debug("__put_ioctx: freeing %p\n", ctx); | |
224 | call_rcu(&ctx->rcu_head, ctx_rcu_free); | |
225 | } | |
226 | ||
227 | static inline int try_get_ioctx(struct kioctx *kioctx) | |
228 | { | |
229 | return atomic_inc_not_zero(&kioctx->users); | |
230 | } | |
231 | ||
232 | static inline void put_ioctx(struct kioctx *kioctx) | |
233 | { | |
234 | BUG_ON(atomic_read(&kioctx->users) <= 0); | |
235 | if (unlikely(atomic_dec_and_test(&kioctx->users))) | |
236 | __put_ioctx(kioctx); | |
237 | } | |
238 | ||
239 | /* ioctx_alloc | |
240 | * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. | |
241 | */ | |
242 | static struct kioctx *ioctx_alloc(unsigned nr_events) | |
243 | { | |
244 | struct mm_struct *mm; | |
245 | struct kioctx *ctx; | |
246 | int err = -ENOMEM; | |
247 | ||
248 | /* Prevent overflows */ | |
249 | if ((nr_events > (0x10000000U / sizeof(struct io_event))) || | |
250 | (nr_events > (0x10000000U / sizeof(struct kiocb)))) { | |
251 | pr_debug("ENOMEM: nr_events too high\n"); | |
252 | return ERR_PTR(-EINVAL); | |
253 | } | |
254 | ||
255 | if (!nr_events || (unsigned long)nr_events > aio_max_nr) | |
256 | return ERR_PTR(-EAGAIN); | |
257 | ||
258 | ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); | |
259 | if (!ctx) | |
260 | return ERR_PTR(-ENOMEM); | |
261 | ||
262 | ctx->max_reqs = nr_events; | |
263 | mm = ctx->mm = current->mm; | |
264 | atomic_inc(&mm->mm_count); | |
265 | ||
266 | atomic_set(&ctx->users, 2); | |
267 | spin_lock_init(&ctx->ctx_lock); | |
268 | spin_lock_init(&ctx->ring_info.ring_lock); | |
269 | init_waitqueue_head(&ctx->wait); | |
270 | ||
271 | INIT_LIST_HEAD(&ctx->active_reqs); | |
272 | INIT_LIST_HEAD(&ctx->run_list); | |
273 | INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler); | |
274 | ||
275 | if (aio_setup_ring(ctx) < 0) | |
276 | goto out_freectx; | |
277 | ||
278 | /* limit the number of system wide aios */ | |
279 | spin_lock(&aio_nr_lock); | |
280 | if (aio_nr + nr_events > aio_max_nr || | |
281 | aio_nr + nr_events < aio_nr) { | |
282 | spin_unlock(&aio_nr_lock); | |
283 | goto out_cleanup; | |
284 | } | |
285 | aio_nr += ctx->max_reqs; | |
286 | spin_unlock(&aio_nr_lock); | |
287 | ||
288 | /* now link into global list. */ | |
289 | spin_lock(&mm->ioctx_lock); | |
290 | hlist_add_head_rcu(&ctx->list, &mm->ioctx_list); | |
291 | spin_unlock(&mm->ioctx_lock); | |
292 | ||
293 | dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", | |
294 | ctx, ctx->user_id, current->mm, ctx->ring_info.nr); | |
295 | return ctx; | |
296 | ||
297 | out_cleanup: | |
298 | err = -EAGAIN; | |
299 | aio_free_ring(ctx); | |
300 | out_freectx: | |
301 | mmdrop(mm); | |
302 | kmem_cache_free(kioctx_cachep, ctx); | |
303 | dprintk("aio: error allocating ioctx %d\n", err); | |
304 | return ERR_PTR(err); | |
305 | } | |
306 | ||
307 | /* kill_ctx | |
308 | * Cancels all outstanding aio requests on an aio context. Used | |
309 | * when the processes owning a context have all exited to encourage | |
310 | * the rapid destruction of the kioctx. | |
311 | */ | |
312 | static void kill_ctx(struct kioctx *ctx) | |
313 | { | |
314 | int (*cancel)(struct kiocb *, struct io_event *); | |
315 | struct task_struct *tsk = current; | |
316 | DECLARE_WAITQUEUE(wait, tsk); | |
317 | struct io_event res; | |
318 | ||
319 | spin_lock_irq(&ctx->ctx_lock); | |
320 | ctx->dead = 1; | |
321 | while (!list_empty(&ctx->active_reqs)) { | |
322 | struct list_head *pos = ctx->active_reqs.next; | |
323 | struct kiocb *iocb = list_kiocb(pos); | |
324 | list_del_init(&iocb->ki_list); | |
325 | cancel = iocb->ki_cancel; | |
326 | kiocbSetCancelled(iocb); | |
327 | if (cancel) { | |
328 | iocb->ki_users++; | |
329 | spin_unlock_irq(&ctx->ctx_lock); | |
330 | cancel(iocb, &res); | |
331 | spin_lock_irq(&ctx->ctx_lock); | |
332 | } | |
333 | } | |
334 | ||
335 | if (!ctx->reqs_active) | |
336 | goto out; | |
337 | ||
338 | add_wait_queue(&ctx->wait, &wait); | |
339 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
340 | while (ctx->reqs_active) { | |
341 | spin_unlock_irq(&ctx->ctx_lock); | |
342 | io_schedule(); | |
343 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); | |
344 | spin_lock_irq(&ctx->ctx_lock); | |
345 | } | |
346 | __set_task_state(tsk, TASK_RUNNING); | |
347 | remove_wait_queue(&ctx->wait, &wait); | |
348 | ||
349 | out: | |
350 | spin_unlock_irq(&ctx->ctx_lock); | |
351 | } | |
352 | ||
353 | /* wait_on_sync_kiocb: | |
354 | * Waits on the given sync kiocb to complete. | |
355 | */ | |
356 | ssize_t wait_on_sync_kiocb(struct kiocb *iocb) | |
357 | { | |
358 | while (iocb->ki_users) { | |
359 | set_current_state(TASK_UNINTERRUPTIBLE); | |
360 | if (!iocb->ki_users) | |
361 | break; | |
362 | io_schedule(); | |
363 | } | |
364 | __set_current_state(TASK_RUNNING); | |
365 | return iocb->ki_user_data; | |
366 | } | |
367 | EXPORT_SYMBOL(wait_on_sync_kiocb); | |
368 | ||
369 | /* exit_aio: called when the last user of mm goes away. At this point, | |
370 | * there is no way for any new requests to be submited or any of the | |
371 | * io_* syscalls to be called on the context. However, there may be | |
372 | * outstanding requests which hold references to the context; as they | |
373 | * go away, they will call put_ioctx and release any pinned memory | |
374 | * associated with the request (held via struct page * references). | |
375 | */ | |
376 | void exit_aio(struct mm_struct *mm) | |
377 | { | |
378 | struct kioctx *ctx; | |
379 | ||
380 | while (!hlist_empty(&mm->ioctx_list)) { | |
381 | ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list); | |
382 | hlist_del_rcu(&ctx->list); | |
383 | ||
384 | kill_ctx(ctx); | |
385 | ||
386 | if (1 != atomic_read(&ctx->users)) | |
387 | printk(KERN_DEBUG | |
388 | "exit_aio:ioctx still alive: %d %d %d\n", | |
389 | atomic_read(&ctx->users), ctx->dead, | |
390 | ctx->reqs_active); | |
391 | /* | |
392 | * We don't need to bother with munmap() here - | |
393 | * exit_mmap(mm) is coming and it'll unmap everything. | |
394 | * Since aio_free_ring() uses non-zero ->mmap_size | |
395 | * as indicator that it needs to unmap the area, | |
396 | * just set it to 0; aio_free_ring() is the only | |
397 | * place that uses ->mmap_size, so it's safe. | |
398 | * That way we get all munmap done to current->mm - | |
399 | * all other callers have ctx->mm == current->mm. | |
400 | */ | |
401 | ctx->ring_info.mmap_size = 0; | |
402 | put_ioctx(ctx); | |
403 | } | |
404 | } | |
405 | ||
406 | /* aio_get_req | |
407 | * Allocate a slot for an aio request. Increments the users count | |
408 | * of the kioctx so that the kioctx stays around until all requests are | |
409 | * complete. Returns NULL if no requests are free. | |
410 | * | |
411 | * Returns with kiocb->users set to 2. The io submit code path holds | |
412 | * an extra reference while submitting the i/o. | |
413 | * This prevents races between the aio code path referencing the | |
414 | * req (after submitting it) and aio_complete() freeing the req. | |
415 | */ | |
416 | static struct kiocb *__aio_get_req(struct kioctx *ctx) | |
417 | { | |
418 | struct kiocb *req = NULL; | |
419 | ||
420 | req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); | |
421 | if (unlikely(!req)) | |
422 | return NULL; | |
423 | ||
424 | req->ki_flags = 0; | |
425 | req->ki_users = 2; | |
426 | req->ki_key = 0; | |
427 | req->ki_ctx = ctx; | |
428 | req->ki_cancel = NULL; | |
429 | req->ki_retry = NULL; | |
430 | req->ki_dtor = NULL; | |
431 | req->private = NULL; | |
432 | req->ki_iovec = NULL; | |
433 | INIT_LIST_HEAD(&req->ki_run_list); | |
434 | req->ki_eventfd = NULL; | |
435 | ||
436 | return req; | |
437 | } | |
438 | ||
439 | /* | |
440 | * struct kiocb's are allocated in batches to reduce the number of | |
441 | * times the ctx lock is acquired and released. | |
442 | */ | |
443 | #define KIOCB_BATCH_SIZE 32L | |
444 | struct kiocb_batch { | |
445 | struct list_head head; | |
446 | long count; /* number of requests left to allocate */ | |
447 | }; | |
448 | ||
449 | static void kiocb_batch_init(struct kiocb_batch *batch, long total) | |
450 | { | |
451 | INIT_LIST_HEAD(&batch->head); | |
452 | batch->count = total; | |
453 | } | |
454 | ||
455 | static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch) | |
456 | { | |
457 | struct kiocb *req, *n; | |
458 | ||
459 | if (list_empty(&batch->head)) | |
460 | return; | |
461 | ||
462 | spin_lock_irq(&ctx->ctx_lock); | |
463 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { | |
464 | list_del(&req->ki_batch); | |
465 | list_del(&req->ki_list); | |
466 | kmem_cache_free(kiocb_cachep, req); | |
467 | ctx->reqs_active--; | |
468 | } | |
469 | if (unlikely(!ctx->reqs_active && ctx->dead)) | |
470 | wake_up_all(&ctx->wait); | |
471 | spin_unlock_irq(&ctx->ctx_lock); | |
472 | } | |
473 | ||
474 | /* | |
475 | * Allocate a batch of kiocbs. This avoids taking and dropping the | |
476 | * context lock a lot during setup. | |
477 | */ | |
478 | static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch) | |
479 | { | |
480 | unsigned short allocated, to_alloc; | |
481 | long avail; | |
482 | bool called_fput = false; | |
483 | struct kiocb *req, *n; | |
484 | struct aio_ring *ring; | |
485 | ||
486 | to_alloc = min(batch->count, KIOCB_BATCH_SIZE); | |
487 | for (allocated = 0; allocated < to_alloc; allocated++) { | |
488 | req = __aio_get_req(ctx); | |
489 | if (!req) | |
490 | /* allocation failed, go with what we've got */ | |
491 | break; | |
492 | list_add(&req->ki_batch, &batch->head); | |
493 | } | |
494 | ||
495 | if (allocated == 0) | |
496 | goto out; | |
497 | ||
498 | retry: | |
499 | spin_lock_irq(&ctx->ctx_lock); | |
500 | ring = kmap_atomic(ctx->ring_info.ring_pages[0]); | |
501 | ||
502 | avail = aio_ring_avail(&ctx->ring_info, ring) - ctx->reqs_active; | |
503 | BUG_ON(avail < 0); | |
504 | if (avail == 0 && !called_fput) { | |
505 | /* | |
506 | * Handle a potential starvation case. It is possible that | |
507 | * we hold the last reference on a struct file, causing us | |
508 | * to delay the final fput to non-irq context. In this case, | |
509 | * ctx->reqs_active is artificially high. Calling the fput | |
510 | * routine here may free up a slot in the event completion | |
511 | * ring, allowing this allocation to succeed. | |
512 | */ | |
513 | kunmap_atomic(ring); | |
514 | spin_unlock_irq(&ctx->ctx_lock); | |
515 | aio_fput_routine(NULL); | |
516 | called_fput = true; | |
517 | goto retry; | |
518 | } | |
519 | ||
520 | if (avail < allocated) { | |
521 | /* Trim back the number of requests. */ | |
522 | list_for_each_entry_safe(req, n, &batch->head, ki_batch) { | |
523 | list_del(&req->ki_batch); | |
524 | kmem_cache_free(kiocb_cachep, req); | |
525 | if (--allocated <= avail) | |
526 | break; | |
527 | } | |
528 | } | |
529 | ||
530 | batch->count -= allocated; | |
531 | list_for_each_entry(req, &batch->head, ki_batch) { | |
532 | list_add(&req->ki_list, &ctx->active_reqs); | |
533 | ctx->reqs_active++; | |
534 | } | |
535 | ||
536 | kunmap_atomic(ring); | |
537 | spin_unlock_irq(&ctx->ctx_lock); | |
538 | ||
539 | out: | |
540 | return allocated; | |
541 | } | |
542 | ||
543 | static inline struct kiocb *aio_get_req(struct kioctx *ctx, | |
544 | struct kiocb_batch *batch) | |
545 | { | |
546 | struct kiocb *req; | |
547 | ||
548 | if (list_empty(&batch->head)) | |
549 | if (kiocb_batch_refill(ctx, batch) == 0) | |
550 | return NULL; | |
551 | req = list_first_entry(&batch->head, struct kiocb, ki_batch); | |
552 | list_del(&req->ki_batch); | |
553 | return req; | |
554 | } | |
555 | ||
556 | static inline void really_put_req(struct kioctx *ctx, struct kiocb *req) | |
557 | { | |
558 | assert_spin_locked(&ctx->ctx_lock); | |
559 | ||
560 | if (req->ki_eventfd != NULL) | |
561 | eventfd_ctx_put(req->ki_eventfd); | |
562 | if (req->ki_dtor) | |
563 | req->ki_dtor(req); | |
564 | if (req->ki_iovec != &req->ki_inline_vec) | |
565 | kfree(req->ki_iovec); | |
566 | kmem_cache_free(kiocb_cachep, req); | |
567 | ctx->reqs_active--; | |
568 | ||
569 | if (unlikely(!ctx->reqs_active && ctx->dead)) | |
570 | wake_up_all(&ctx->wait); | |
571 | } | |
572 | ||
573 | static void aio_fput_routine(struct work_struct *data) | |
574 | { | |
575 | spin_lock_irq(&fput_lock); | |
576 | while (likely(!list_empty(&fput_head))) { | |
577 | struct kiocb *req = list_kiocb(fput_head.next); | |
578 | struct kioctx *ctx = req->ki_ctx; | |
579 | ||
580 | list_del(&req->ki_list); | |
581 | spin_unlock_irq(&fput_lock); | |
582 | ||
583 | /* Complete the fput(s) */ | |
584 | if (req->ki_filp != NULL) | |
585 | fput(req->ki_filp); | |
586 | ||
587 | /* Link the iocb into the context's free list */ | |
588 | rcu_read_lock(); | |
589 | spin_lock_irq(&ctx->ctx_lock); | |
590 | really_put_req(ctx, req); | |
591 | /* | |
592 | * at that point ctx might've been killed, but actual | |
593 | * freeing is RCU'd | |
594 | */ | |
595 | spin_unlock_irq(&ctx->ctx_lock); | |
596 | rcu_read_unlock(); | |
597 | ||
598 | spin_lock_irq(&fput_lock); | |
599 | } | |
600 | spin_unlock_irq(&fput_lock); | |
601 | } | |
602 | ||
603 | /* __aio_put_req | |
604 | * Returns true if this put was the last user of the request. | |
605 | */ | |
606 | static int __aio_put_req(struct kioctx *ctx, struct kiocb *req) | |
607 | { | |
608 | dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n", | |
609 | req, atomic_long_read(&req->ki_filp->f_count)); | |
610 | ||
611 | assert_spin_locked(&ctx->ctx_lock); | |
612 | ||
613 | req->ki_users--; | |
614 | BUG_ON(req->ki_users < 0); | |
615 | if (likely(req->ki_users)) | |
616 | return 0; | |
617 | list_del(&req->ki_list); /* remove from active_reqs */ | |
618 | req->ki_cancel = NULL; | |
619 | req->ki_retry = NULL; | |
620 | ||
621 | /* | |
622 | * Try to optimize the aio and eventfd file* puts, by avoiding to | |
623 | * schedule work in case it is not final fput() time. In normal cases, | |
624 | * we would not be holding the last reference to the file*, so | |
625 | * this function will be executed w/out any aio kthread wakeup. | |
626 | */ | |
627 | if (unlikely(!fput_atomic(req->ki_filp))) { | |
628 | spin_lock(&fput_lock); | |
629 | list_add(&req->ki_list, &fput_head); | |
630 | spin_unlock(&fput_lock); | |
631 | schedule_work(&fput_work); | |
632 | } else { | |
633 | req->ki_filp = NULL; | |
634 | really_put_req(ctx, req); | |
635 | } | |
636 | return 1; | |
637 | } | |
638 | ||
639 | /* aio_put_req | |
640 | * Returns true if this put was the last user of the kiocb, | |
641 | * false if the request is still in use. | |
642 | */ | |
643 | int aio_put_req(struct kiocb *req) | |
644 | { | |
645 | struct kioctx *ctx = req->ki_ctx; | |
646 | int ret; | |
647 | spin_lock_irq(&ctx->ctx_lock); | |
648 | ret = __aio_put_req(ctx, req); | |
649 | spin_unlock_irq(&ctx->ctx_lock); | |
650 | return ret; | |
651 | } | |
652 | EXPORT_SYMBOL(aio_put_req); | |
653 | ||
654 | static struct kioctx *lookup_ioctx(unsigned long ctx_id) | |
655 | { | |
656 | struct mm_struct *mm = current->mm; | |
657 | struct kioctx *ctx, *ret = NULL; | |
658 | struct hlist_node *n; | |
659 | ||
660 | rcu_read_lock(); | |
661 | ||
662 | hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { | |
663 | /* | |
664 | * RCU protects us against accessing freed memory but | |
665 | * we have to be careful not to get a reference when the | |
666 | * reference count already dropped to 0 (ctx->dead test | |
667 | * is unreliable because of races). | |
668 | */ | |
669 | if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){ | |
670 | ret = ctx; | |
671 | break; | |
672 | } | |
673 | } | |
674 | ||
675 | rcu_read_unlock(); | |
676 | return ret; | |
677 | } | |
678 | ||
679 | /* | |
680 | * Queue up a kiocb to be retried. Assumes that the kiocb | |
681 | * has already been marked as kicked, and places it on | |
682 | * the retry run list for the corresponding ioctx, if it | |
683 | * isn't already queued. Returns 1 if it actually queued | |
684 | * the kiocb (to tell the caller to activate the work | |
685 | * queue to process it), or 0, if it found that it was | |
686 | * already queued. | |
687 | */ | |
688 | static inline int __queue_kicked_iocb(struct kiocb *iocb) | |
689 | { | |
690 | struct kioctx *ctx = iocb->ki_ctx; | |
691 | ||
692 | assert_spin_locked(&ctx->ctx_lock); | |
693 | ||
694 | if (list_empty(&iocb->ki_run_list)) { | |
695 | list_add_tail(&iocb->ki_run_list, | |
696 | &ctx->run_list); | |
697 | return 1; | |
698 | } | |
699 | return 0; | |
700 | } | |
701 | ||
702 | /* aio_run_iocb | |
703 | * This is the core aio execution routine. It is | |
704 | * invoked both for initial i/o submission and | |
705 | * subsequent retries via the aio_kick_handler. | |
706 | * Expects to be invoked with iocb->ki_ctx->lock | |
707 | * already held. The lock is released and reacquired | |
708 | * as needed during processing. | |
709 | * | |
710 | * Calls the iocb retry method (already setup for the | |
711 | * iocb on initial submission) for operation specific | |
712 | * handling, but takes care of most of common retry | |
713 | * execution details for a given iocb. The retry method | |
714 | * needs to be non-blocking as far as possible, to avoid | |
715 | * holding up other iocbs waiting to be serviced by the | |
716 | * retry kernel thread. | |
717 | * | |
718 | * The trickier parts in this code have to do with | |
719 | * ensuring that only one retry instance is in progress | |
720 | * for a given iocb at any time. Providing that guarantee | |
721 | * simplifies the coding of individual aio operations as | |
722 | * it avoids various potential races. | |
723 | */ | |
724 | static ssize_t aio_run_iocb(struct kiocb *iocb) | |
725 | { | |
726 | struct kioctx *ctx = iocb->ki_ctx; | |
727 | ssize_t (*retry)(struct kiocb *); | |
728 | ssize_t ret; | |
729 | ||
730 | if (!(retry = iocb->ki_retry)) { | |
731 | printk("aio_run_iocb: iocb->ki_retry = NULL\n"); | |
732 | return 0; | |
733 | } | |
734 | ||
735 | /* | |
736 | * We don't want the next retry iteration for this | |
737 | * operation to start until this one has returned and | |
738 | * updated the iocb state. However, wait_queue functions | |
739 | * can trigger a kick_iocb from interrupt context in the | |
740 | * meantime, indicating that data is available for the next | |
741 | * iteration. We want to remember that and enable the | |
742 | * next retry iteration _after_ we are through with | |
743 | * this one. | |
744 | * | |
745 | * So, in order to be able to register a "kick", but | |
746 | * prevent it from being queued now, we clear the kick | |
747 | * flag, but make the kick code *think* that the iocb is | |
748 | * still on the run list until we are actually done. | |
749 | * When we are done with this iteration, we check if | |
750 | * the iocb was kicked in the meantime and if so, queue | |
751 | * it up afresh. | |
752 | */ | |
753 | ||
754 | kiocbClearKicked(iocb); | |
755 | ||
756 | /* | |
757 | * This is so that aio_complete knows it doesn't need to | |
758 | * pull the iocb off the run list (We can't just call | |
759 | * INIT_LIST_HEAD because we don't want a kick_iocb to | |
760 | * queue this on the run list yet) | |
761 | */ | |
762 | iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL; | |
763 | spin_unlock_irq(&ctx->ctx_lock); | |
764 | ||
765 | /* Quit retrying if the i/o has been cancelled */ | |
766 | if (kiocbIsCancelled(iocb)) { | |
767 | ret = -EINTR; | |
768 | aio_complete(iocb, ret, 0); | |
769 | /* must not access the iocb after this */ | |
770 | goto out; | |
771 | } | |
772 | ||
773 | /* | |
774 | * Now we are all set to call the retry method in async | |
775 | * context. | |
776 | */ | |
777 | ret = retry(iocb); | |
778 | ||
779 | if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) { | |
780 | /* | |
781 | * There's no easy way to restart the syscall since other AIO's | |
782 | * may be already running. Just fail this IO with EINTR. | |
783 | */ | |
784 | if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || | |
785 | ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK)) | |
786 | ret = -EINTR; | |
787 | aio_complete(iocb, ret, 0); | |
788 | } | |
789 | out: | |
790 | spin_lock_irq(&ctx->ctx_lock); | |
791 | ||
792 | if (-EIOCBRETRY == ret) { | |
793 | /* | |
794 | * OK, now that we are done with this iteration | |
795 | * and know that there is more left to go, | |
796 | * this is where we let go so that a subsequent | |
797 | * "kick" can start the next iteration | |
798 | */ | |
799 | ||
800 | /* will make __queue_kicked_iocb succeed from here on */ | |
801 | INIT_LIST_HEAD(&iocb->ki_run_list); | |
802 | /* we must queue the next iteration ourselves, if it | |
803 | * has already been kicked */ | |
804 | if (kiocbIsKicked(iocb)) { | |
805 | __queue_kicked_iocb(iocb); | |
806 | ||
807 | /* | |
808 | * __queue_kicked_iocb will always return 1 here, because | |
809 | * iocb->ki_run_list is empty at this point so it should | |
810 | * be safe to unconditionally queue the context into the | |
811 | * work queue. | |
812 | */ | |
813 | aio_queue_work(ctx); | |
814 | } | |
815 | } | |
816 | return ret; | |
817 | } | |
818 | ||
819 | /* | |
820 | * __aio_run_iocbs: | |
821 | * Process all pending retries queued on the ioctx | |
822 | * run list. | |
823 | * Assumes it is operating within the aio issuer's mm | |
824 | * context. | |
825 | */ | |
826 | static int __aio_run_iocbs(struct kioctx *ctx) | |
827 | { | |
828 | struct kiocb *iocb; | |
829 | struct list_head run_list; | |
830 | ||
831 | assert_spin_locked(&ctx->ctx_lock); | |
832 | ||
833 | list_replace_init(&ctx->run_list, &run_list); | |
834 | while (!list_empty(&run_list)) { | |
835 | iocb = list_entry(run_list.next, struct kiocb, | |
836 | ki_run_list); | |
837 | list_del(&iocb->ki_run_list); | |
838 | /* | |
839 | * Hold an extra reference while retrying i/o. | |
840 | */ | |
841 | iocb->ki_users++; /* grab extra reference */ | |
842 | aio_run_iocb(iocb); | |
843 | __aio_put_req(ctx, iocb); | |
844 | } | |
845 | if (!list_empty(&ctx->run_list)) | |
846 | return 1; | |
847 | return 0; | |
848 | } | |
849 | ||
850 | static void aio_queue_work(struct kioctx * ctx) | |
851 | { | |
852 | unsigned long timeout; | |
853 | /* | |
854 | * if someone is waiting, get the work started right | |
855 | * away, otherwise, use a longer delay | |
856 | */ | |
857 | smp_mb(); | |
858 | if (waitqueue_active(&ctx->wait)) | |
859 | timeout = 1; | |
860 | else | |
861 | timeout = HZ/10; | |
862 | queue_delayed_work(aio_wq, &ctx->wq, timeout); | |
863 | } | |
864 | ||
865 | /* | |
866 | * aio_run_all_iocbs: | |
867 | * Process all pending retries queued on the ioctx | |
868 | * run list, and keep running them until the list | |
869 | * stays empty. | |
870 | * Assumes it is operating within the aio issuer's mm context. | |
871 | */ | |
872 | static inline void aio_run_all_iocbs(struct kioctx *ctx) | |
873 | { | |
874 | spin_lock_irq(&ctx->ctx_lock); | |
875 | while (__aio_run_iocbs(ctx)) | |
876 | ; | |
877 | spin_unlock_irq(&ctx->ctx_lock); | |
878 | } | |
879 | ||
880 | /* | |
881 | * aio_kick_handler: | |
882 | * Work queue handler triggered to process pending | |
883 | * retries on an ioctx. Takes on the aio issuer's | |
884 | * mm context before running the iocbs, so that | |
885 | * copy_xxx_user operates on the issuer's address | |
886 | * space. | |
887 | * Run on aiod's context. | |
888 | */ | |
889 | static void aio_kick_handler(struct work_struct *work) | |
890 | { | |
891 | struct kioctx *ctx = container_of(work, struct kioctx, wq.work); | |
892 | mm_segment_t oldfs = get_fs(); | |
893 | struct mm_struct *mm; | |
894 | int requeue; | |
895 | ||
896 | set_fs(USER_DS); | |
897 | use_mm(ctx->mm); | |
898 | spin_lock_irq(&ctx->ctx_lock); | |
899 | requeue =__aio_run_iocbs(ctx); | |
900 | mm = ctx->mm; | |
901 | spin_unlock_irq(&ctx->ctx_lock); | |
902 | unuse_mm(mm); | |
903 | set_fs(oldfs); | |
904 | /* | |
905 | * we're in a worker thread already; no point using non-zero delay | |
906 | */ | |
907 | if (requeue) | |
908 | queue_delayed_work(aio_wq, &ctx->wq, 0); | |
909 | } | |
910 | ||
911 | ||
912 | /* | |
913 | * Called by kick_iocb to queue the kiocb for retry | |
914 | * and if required activate the aio work queue to process | |
915 | * it | |
916 | */ | |
917 | static void try_queue_kicked_iocb(struct kiocb *iocb) | |
918 | { | |
919 | struct kioctx *ctx = iocb->ki_ctx; | |
920 | unsigned long flags; | |
921 | int run = 0; | |
922 | ||
923 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
924 | /* set this inside the lock so that we can't race with aio_run_iocb() | |
925 | * testing it and putting the iocb on the run list under the lock */ | |
926 | if (!kiocbTryKick(iocb)) | |
927 | run = __queue_kicked_iocb(iocb); | |
928 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
929 | if (run) | |
930 | aio_queue_work(ctx); | |
931 | } | |
932 | ||
933 | /* | |
934 | * kick_iocb: | |
935 | * Called typically from a wait queue callback context | |
936 | * to trigger a retry of the iocb. | |
937 | * The retry is usually executed by aio workqueue | |
938 | * threads (See aio_kick_handler). | |
939 | */ | |
940 | void kick_iocb(struct kiocb *iocb) | |
941 | { | |
942 | /* sync iocbs are easy: they can only ever be executing from a | |
943 | * single context. */ | |
944 | if (is_sync_kiocb(iocb)) { | |
945 | kiocbSetKicked(iocb); | |
946 | wake_up_process(iocb->ki_obj.tsk); | |
947 | return; | |
948 | } | |
949 | ||
950 | try_queue_kicked_iocb(iocb); | |
951 | } | |
952 | EXPORT_SYMBOL(kick_iocb); | |
953 | ||
954 | /* aio_complete | |
955 | * Called when the io request on the given iocb is complete. | |
956 | * Returns true if this is the last user of the request. The | |
957 | * only other user of the request can be the cancellation code. | |
958 | */ | |
959 | int aio_complete(struct kiocb *iocb, long res, long res2) | |
960 | { | |
961 | struct kioctx *ctx = iocb->ki_ctx; | |
962 | struct aio_ring_info *info; | |
963 | struct aio_ring *ring; | |
964 | struct io_event *event; | |
965 | unsigned long flags; | |
966 | unsigned long tail; | |
967 | int ret; | |
968 | ||
969 | /* | |
970 | * Special case handling for sync iocbs: | |
971 | * - events go directly into the iocb for fast handling | |
972 | * - the sync task with the iocb in its stack holds the single iocb | |
973 | * ref, no other paths have a way to get another ref | |
974 | * - the sync task helpfully left a reference to itself in the iocb | |
975 | */ | |
976 | if (is_sync_kiocb(iocb)) { | |
977 | BUG_ON(iocb->ki_users != 1); | |
978 | iocb->ki_user_data = res; | |
979 | iocb->ki_users = 0; | |
980 | wake_up_process(iocb->ki_obj.tsk); | |
981 | return 1; | |
982 | } | |
983 | ||
984 | info = &ctx->ring_info; | |
985 | ||
986 | /* add a completion event to the ring buffer. | |
987 | * must be done holding ctx->ctx_lock to prevent | |
988 | * other code from messing with the tail | |
989 | * pointer since we might be called from irq | |
990 | * context. | |
991 | */ | |
992 | spin_lock_irqsave(&ctx->ctx_lock, flags); | |
993 | ||
994 | if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list)) | |
995 | list_del_init(&iocb->ki_run_list); | |
996 | ||
997 | /* | |
998 | * cancelled requests don't get events, userland was given one | |
999 | * when the event got cancelled. | |
1000 | */ | |
1001 | if (kiocbIsCancelled(iocb)) | |
1002 | goto put_rq; | |
1003 | ||
1004 | ring = kmap_atomic(info->ring_pages[0]); | |
1005 | ||
1006 | tail = info->tail; | |
1007 | event = aio_ring_event(info, tail); | |
1008 | if (++tail >= info->nr) | |
1009 | tail = 0; | |
1010 | ||
1011 | event->obj = (u64)(unsigned long)iocb->ki_obj.user; | |
1012 | event->data = iocb->ki_user_data; | |
1013 | event->res = res; | |
1014 | event->res2 = res2; | |
1015 | ||
1016 | dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n", | |
1017 | ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data, | |
1018 | res, res2); | |
1019 | ||
1020 | /* after flagging the request as done, we | |
1021 | * must never even look at it again | |
1022 | */ | |
1023 | smp_wmb(); /* make event visible before updating tail */ | |
1024 | ||
1025 | info->tail = tail; | |
1026 | ring->tail = tail; | |
1027 | ||
1028 | put_aio_ring_event(event); | |
1029 | kunmap_atomic(ring); | |
1030 | ||
1031 | pr_debug("added to ring %p at [%lu]\n", iocb, tail); | |
1032 | ||
1033 | /* | |
1034 | * Check if the user asked us to deliver the result through an | |
1035 | * eventfd. The eventfd_signal() function is safe to be called | |
1036 | * from IRQ context. | |
1037 | */ | |
1038 | if (iocb->ki_eventfd != NULL) | |
1039 | eventfd_signal(iocb->ki_eventfd, 1); | |
1040 | ||
1041 | put_rq: | |
1042 | /* everything turned out well, dispose of the aiocb. */ | |
1043 | ret = __aio_put_req(ctx, iocb); | |
1044 | ||
1045 | /* | |
1046 | * We have to order our ring_info tail store above and test | |
1047 | * of the wait list below outside the wait lock. This is | |
1048 | * like in wake_up_bit() where clearing a bit has to be | |
1049 | * ordered with the unlocked test. | |
1050 | */ | |
1051 | smp_mb(); | |
1052 | ||
1053 | if (waitqueue_active(&ctx->wait)) | |
1054 | wake_up(&ctx->wait); | |
1055 | ||
1056 | spin_unlock_irqrestore(&ctx->ctx_lock, flags); | |
1057 | return ret; | |
1058 | } | |
1059 | EXPORT_SYMBOL(aio_complete); | |
1060 | ||
1061 | /* aio_read_evt | |
1062 | * Pull an event off of the ioctx's event ring. Returns the number of | |
1063 | * events fetched (0 or 1 ;-) | |
1064 | * FIXME: make this use cmpxchg. | |
1065 | * TODO: make the ringbuffer user mmap()able (requires FIXME). | |
1066 | */ | |
1067 | static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent) | |
1068 | { | |
1069 | struct aio_ring_info *info = &ioctx->ring_info; | |
1070 | struct aio_ring *ring; | |
1071 | unsigned long head; | |
1072 | int ret = 0; | |
1073 | ||
1074 | ring = kmap_atomic(info->ring_pages[0]); | |
1075 | dprintk("in aio_read_evt h%lu t%lu m%lu\n", | |
1076 | (unsigned long)ring->head, (unsigned long)ring->tail, | |
1077 | (unsigned long)ring->nr); | |
1078 | ||
1079 | if (ring->head == ring->tail) | |
1080 | goto out; | |
1081 | ||
1082 | spin_lock(&info->ring_lock); | |
1083 | ||
1084 | head = ring->head % info->nr; | |
1085 | if (head != ring->tail) { | |
1086 | struct io_event *evp = aio_ring_event(info, head); | |
1087 | *ent = *evp; | |
1088 | head = (head + 1) % info->nr; | |
1089 | smp_mb(); /* finish reading the event before updatng the head */ | |
1090 | ring->head = head; | |
1091 | ret = 1; | |
1092 | put_aio_ring_event(evp); | |
1093 | } | |
1094 | spin_unlock(&info->ring_lock); | |
1095 | ||
1096 | out: | |
1097 | kunmap_atomic(ring); | |
1098 | dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret, | |
1099 | (unsigned long)ring->head, (unsigned long)ring->tail); | |
1100 | return ret; | |
1101 | } | |
1102 | ||
1103 | struct aio_timeout { | |
1104 | struct timer_list timer; | |
1105 | int timed_out; | |
1106 | struct task_struct *p; | |
1107 | }; | |
1108 | ||
1109 | static void timeout_func(unsigned long data) | |
1110 | { | |
1111 | struct aio_timeout *to = (struct aio_timeout *)data; | |
1112 | ||
1113 | to->timed_out = 1; | |
1114 | wake_up_process(to->p); | |
1115 | } | |
1116 | ||
1117 | static inline void init_timeout(struct aio_timeout *to) | |
1118 | { | |
1119 | setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to); | |
1120 | to->timed_out = 0; | |
1121 | to->p = current; | |
1122 | } | |
1123 | ||
1124 | static inline void set_timeout(long start_jiffies, struct aio_timeout *to, | |
1125 | const struct timespec *ts) | |
1126 | { | |
1127 | to->timer.expires = start_jiffies + timespec_to_jiffies(ts); | |
1128 | if (time_after(to->timer.expires, jiffies)) | |
1129 | add_timer(&to->timer); | |
1130 | else | |
1131 | to->timed_out = 1; | |
1132 | } | |
1133 | ||
1134 | static inline void clear_timeout(struct aio_timeout *to) | |
1135 | { | |
1136 | del_singleshot_timer_sync(&to->timer); | |
1137 | } | |
1138 | ||
1139 | static int read_events(struct kioctx *ctx, | |
1140 | long min_nr, long nr, | |
1141 | struct io_event __user *event, | |
1142 | struct timespec __user *timeout) | |
1143 | { | |
1144 | long start_jiffies = jiffies; | |
1145 | struct task_struct *tsk = current; | |
1146 | DECLARE_WAITQUEUE(wait, tsk); | |
1147 | int ret; | |
1148 | int i = 0; | |
1149 | struct io_event ent; | |
1150 | struct aio_timeout to; | |
1151 | int retry = 0; | |
1152 | ||
1153 | /* needed to zero any padding within an entry (there shouldn't be | |
1154 | * any, but C is fun! | |
1155 | */ | |
1156 | memset(&ent, 0, sizeof(ent)); | |
1157 | retry: | |
1158 | ret = 0; | |
1159 | while (likely(i < nr)) { | |
1160 | ret = aio_read_evt(ctx, &ent); | |
1161 | if (unlikely(ret <= 0)) | |
1162 | break; | |
1163 | ||
1164 | dprintk("read event: %Lx %Lx %Lx %Lx\n", | |
1165 | ent.data, ent.obj, ent.res, ent.res2); | |
1166 | ||
1167 | /* Could we split the check in two? */ | |
1168 | ret = -EFAULT; | |
1169 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { | |
1170 | dprintk("aio: lost an event due to EFAULT.\n"); | |
1171 | break; | |
1172 | } | |
1173 | ret = 0; | |
1174 | ||
1175 | /* Good, event copied to userland, update counts. */ | |
1176 | event ++; | |
1177 | i ++; | |
1178 | } | |
1179 | ||
1180 | if (min_nr <= i) | |
1181 | return i; | |
1182 | if (ret) | |
1183 | return ret; | |
1184 | ||
1185 | /* End fast path */ | |
1186 | ||
1187 | /* racey check, but it gets redone */ | |
1188 | if (!retry && unlikely(!list_empty(&ctx->run_list))) { | |
1189 | retry = 1; | |
1190 | aio_run_all_iocbs(ctx); | |
1191 | goto retry; | |
1192 | } | |
1193 | ||
1194 | init_timeout(&to); | |
1195 | if (timeout) { | |
1196 | struct timespec ts; | |
1197 | ret = -EFAULT; | |
1198 | if (unlikely(copy_from_user(&ts, timeout, sizeof(ts)))) | |
1199 | goto out; | |
1200 | ||
1201 | set_timeout(start_jiffies, &to, &ts); | |
1202 | } | |
1203 | ||
1204 | while (likely(i < nr)) { | |
1205 | add_wait_queue_exclusive(&ctx->wait, &wait); | |
1206 | do { | |
1207 | set_task_state(tsk, TASK_INTERRUPTIBLE); | |
1208 | ret = aio_read_evt(ctx, &ent); | |
1209 | if (ret) | |
1210 | break; | |
1211 | if (min_nr <= i) | |
1212 | break; | |
1213 | if (unlikely(ctx->dead)) { | |
1214 | ret = -EINVAL; | |
1215 | break; | |
1216 | } | |
1217 | if (to.timed_out) /* Only check after read evt */ | |
1218 | break; | |
1219 | /* Try to only show up in io wait if there are ops | |
1220 | * in flight */ | |
1221 | if (ctx->reqs_active) | |
1222 | io_schedule(); | |
1223 | else | |
1224 | schedule(); | |
1225 | if (signal_pending(tsk)) { | |
1226 | ret = -EINTR; | |
1227 | break; | |
1228 | } | |
1229 | /*ret = aio_read_evt(ctx, &ent);*/ | |
1230 | } while (1) ; | |
1231 | ||
1232 | set_task_state(tsk, TASK_RUNNING); | |
1233 | remove_wait_queue(&ctx->wait, &wait); | |
1234 | ||
1235 | if (unlikely(ret <= 0)) | |
1236 | break; | |
1237 | ||
1238 | ret = -EFAULT; | |
1239 | if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) { | |
1240 | dprintk("aio: lost an event due to EFAULT.\n"); | |
1241 | break; | |
1242 | } | |
1243 | ||
1244 | /* Good, event copied to userland, update counts. */ | |
1245 | event ++; | |
1246 | i ++; | |
1247 | } | |
1248 | ||
1249 | if (timeout) | |
1250 | clear_timeout(&to); | |
1251 | out: | |
1252 | destroy_timer_on_stack(&to.timer); | |
1253 | return i ? i : ret; | |
1254 | } | |
1255 | ||
1256 | /* Take an ioctx and remove it from the list of ioctx's. Protects | |
1257 | * against races with itself via ->dead. | |
1258 | */ | |
1259 | static void io_destroy(struct kioctx *ioctx) | |
1260 | { | |
1261 | struct mm_struct *mm = current->mm; | |
1262 | int was_dead; | |
1263 | ||
1264 | /* delete the entry from the list is someone else hasn't already */ | |
1265 | spin_lock(&mm->ioctx_lock); | |
1266 | was_dead = ioctx->dead; | |
1267 | ioctx->dead = 1; | |
1268 | hlist_del_rcu(&ioctx->list); | |
1269 | spin_unlock(&mm->ioctx_lock); | |
1270 | ||
1271 | dprintk("aio_release(%p)\n", ioctx); | |
1272 | if (likely(!was_dead)) | |
1273 | put_ioctx(ioctx); /* twice for the list */ | |
1274 | ||
1275 | kill_ctx(ioctx); | |
1276 | ||
1277 | /* | |
1278 | * Wake up any waiters. The setting of ctx->dead must be seen | |
1279 | * by other CPUs at this point. Right now, we rely on the | |
1280 | * locking done by the above calls to ensure this consistency. | |
1281 | */ | |
1282 | wake_up_all(&ioctx->wait); | |
1283 | } | |
1284 | ||
1285 | /* sys_io_setup: | |
1286 | * Create an aio_context capable of receiving at least nr_events. | |
1287 | * ctxp must not point to an aio_context that already exists, and | |
1288 | * must be initialized to 0 prior to the call. On successful | |
1289 | * creation of the aio_context, *ctxp is filled in with the resulting | |
1290 | * handle. May fail with -EINVAL if *ctxp is not initialized, | |
1291 | * if the specified nr_events exceeds internal limits. May fail | |
1292 | * with -EAGAIN if the specified nr_events exceeds the user's limit | |
1293 | * of available events. May fail with -ENOMEM if insufficient kernel | |
1294 | * resources are available. May fail with -EFAULT if an invalid | |
1295 | * pointer is passed for ctxp. Will fail with -ENOSYS if not | |
1296 | * implemented. | |
1297 | */ | |
1298 | SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) | |
1299 | { | |
1300 | struct kioctx *ioctx = NULL; | |
1301 | unsigned long ctx; | |
1302 | long ret; | |
1303 | ||
1304 | ret = get_user(ctx, ctxp); | |
1305 | if (unlikely(ret)) | |
1306 | goto out; | |
1307 | ||
1308 | ret = -EINVAL; | |
1309 | if (unlikely(ctx || nr_events == 0)) { | |
1310 | pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n", | |
1311 | ctx, nr_events); | |
1312 | goto out; | |
1313 | } | |
1314 | ||
1315 | ioctx = ioctx_alloc(nr_events); | |
1316 | ret = PTR_ERR(ioctx); | |
1317 | if (!IS_ERR(ioctx)) { | |
1318 | ret = put_user(ioctx->user_id, ctxp); | |
1319 | if (ret) | |
1320 | io_destroy(ioctx); | |
1321 | put_ioctx(ioctx); | |
1322 | } | |
1323 | ||
1324 | out: | |
1325 | return ret; | |
1326 | } | |
1327 | ||
1328 | /* sys_io_destroy: | |
1329 | * Destroy the aio_context specified. May cancel any outstanding | |
1330 | * AIOs and block on completion. Will fail with -ENOSYS if not | |
1331 | * implemented. May fail with -EINVAL if the context pointed to | |
1332 | * is invalid. | |
1333 | */ | |
1334 | SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) | |
1335 | { | |
1336 | struct kioctx *ioctx = lookup_ioctx(ctx); | |
1337 | if (likely(NULL != ioctx)) { | |
1338 | io_destroy(ioctx); | |
1339 | put_ioctx(ioctx); | |
1340 | return 0; | |
1341 | } | |
1342 | pr_debug("EINVAL: io_destroy: invalid context id\n"); | |
1343 | return -EINVAL; | |
1344 | } | |
1345 | ||
1346 | static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret) | |
1347 | { | |
1348 | struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg]; | |
1349 | ||
1350 | BUG_ON(ret <= 0); | |
1351 | ||
1352 | while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) { | |
1353 | ssize_t this = min((ssize_t)iov->iov_len, ret); | |
1354 | iov->iov_base += this; | |
1355 | iov->iov_len -= this; | |
1356 | iocb->ki_left -= this; | |
1357 | ret -= this; | |
1358 | if (iov->iov_len == 0) { | |
1359 | iocb->ki_cur_seg++; | |
1360 | iov++; | |
1361 | } | |
1362 | } | |
1363 | ||
1364 | /* the caller should not have done more io than what fit in | |
1365 | * the remaining iovecs */ | |
1366 | BUG_ON(ret > 0 && iocb->ki_left == 0); | |
1367 | } | |
1368 | ||
1369 | static ssize_t aio_rw_vect_retry(struct kiocb *iocb) | |
1370 | { | |
1371 | struct file *file = iocb->ki_filp; | |
1372 | struct address_space *mapping = file->f_mapping; | |
1373 | struct inode *inode = mapping->host; | |
1374 | ssize_t (*rw_op)(struct kiocb *, const struct iovec *, | |
1375 | unsigned long, loff_t); | |
1376 | ssize_t ret = 0; | |
1377 | unsigned short opcode; | |
1378 | ||
1379 | if ((iocb->ki_opcode == IOCB_CMD_PREADV) || | |
1380 | (iocb->ki_opcode == IOCB_CMD_PREAD)) { | |
1381 | rw_op = file->f_op->aio_read; | |
1382 | opcode = IOCB_CMD_PREADV; | |
1383 | } else { | |
1384 | rw_op = file->f_op->aio_write; | |
1385 | opcode = IOCB_CMD_PWRITEV; | |
1386 | } | |
1387 | ||
1388 | /* This matches the pread()/pwrite() logic */ | |
1389 | if (iocb->ki_pos < 0) | |
1390 | return -EINVAL; | |
1391 | ||
1392 | do { | |
1393 | ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg], | |
1394 | iocb->ki_nr_segs - iocb->ki_cur_seg, | |
1395 | iocb->ki_pos); | |
1396 | if (ret > 0) | |
1397 | aio_advance_iovec(iocb, ret); | |
1398 | ||
1399 | /* retry all partial writes. retry partial reads as long as its a | |
1400 | * regular file. */ | |
1401 | } while (ret > 0 && iocb->ki_left > 0 && | |
1402 | (opcode == IOCB_CMD_PWRITEV || | |
1403 | (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode)))); | |
1404 | ||
1405 | /* This means we must have transferred all that we could */ | |
1406 | /* No need to retry anymore */ | |
1407 | if ((ret == 0) || (iocb->ki_left == 0)) | |
1408 | ret = iocb->ki_nbytes - iocb->ki_left; | |
1409 | ||
1410 | /* If we managed to write some out we return that, rather than | |
1411 | * the eventual error. */ | |
1412 | if (opcode == IOCB_CMD_PWRITEV | |
1413 | && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY | |
1414 | && iocb->ki_nbytes - iocb->ki_left) | |
1415 | ret = iocb->ki_nbytes - iocb->ki_left; | |
1416 | ||
1417 | return ret; | |
1418 | } | |
1419 | ||
1420 | static ssize_t aio_fdsync(struct kiocb *iocb) | |
1421 | { | |
1422 | struct file *file = iocb->ki_filp; | |
1423 | ssize_t ret = -EINVAL; | |
1424 | ||
1425 | if (file->f_op->aio_fsync) | |
1426 | ret = file->f_op->aio_fsync(iocb, 1); | |
1427 | return ret; | |
1428 | } | |
1429 | ||
1430 | static ssize_t aio_fsync(struct kiocb *iocb) | |
1431 | { | |
1432 | struct file *file = iocb->ki_filp; | |
1433 | ssize_t ret = -EINVAL; | |
1434 | ||
1435 | if (file->f_op->aio_fsync) | |
1436 | ret = file->f_op->aio_fsync(iocb, 0); | |
1437 | return ret; | |
1438 | } | |
1439 | ||
1440 | static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat) | |
1441 | { | |
1442 | ssize_t ret; | |
1443 | ||
1444 | #ifdef CONFIG_COMPAT | |
1445 | if (compat) | |
1446 | ret = compat_rw_copy_check_uvector(type, | |
1447 | (struct compat_iovec __user *)kiocb->ki_buf, | |
1448 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, | |
1449 | &kiocb->ki_iovec, 1); | |
1450 | else | |
1451 | #endif | |
1452 | ret = rw_copy_check_uvector(type, | |
1453 | (struct iovec __user *)kiocb->ki_buf, | |
1454 | kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec, | |
1455 | &kiocb->ki_iovec, 1); | |
1456 | if (ret < 0) | |
1457 | goto out; | |
1458 | ||
1459 | kiocb->ki_nr_segs = kiocb->ki_nbytes; | |
1460 | kiocb->ki_cur_seg = 0; | |
1461 | /* ki_nbytes/left now reflect bytes instead of segs */ | |
1462 | kiocb->ki_nbytes = ret; | |
1463 | kiocb->ki_left = ret; | |
1464 | ||
1465 | ret = 0; | |
1466 | out: | |
1467 | return ret; | |
1468 | } | |
1469 | ||
1470 | static ssize_t aio_setup_single_vector(struct kiocb *kiocb) | |
1471 | { | |
1472 | kiocb->ki_iovec = &kiocb->ki_inline_vec; | |
1473 | kiocb->ki_iovec->iov_base = kiocb->ki_buf; | |
1474 | kiocb->ki_iovec->iov_len = kiocb->ki_left; | |
1475 | kiocb->ki_nr_segs = 1; | |
1476 | kiocb->ki_cur_seg = 0; | |
1477 | return 0; | |
1478 | } | |
1479 | ||
1480 | /* | |
1481 | * aio_setup_iocb: | |
1482 | * Performs the initial checks and aio retry method | |
1483 | * setup for the kiocb at the time of io submission. | |
1484 | */ | |
1485 | static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat) | |
1486 | { | |
1487 | struct file *file = kiocb->ki_filp; | |
1488 | ssize_t ret = 0; | |
1489 | ||
1490 | switch (kiocb->ki_opcode) { | |
1491 | case IOCB_CMD_PREAD: | |
1492 | ret = -EBADF; | |
1493 | if (unlikely(!(file->f_mode & FMODE_READ))) | |
1494 | break; | |
1495 | ret = -EFAULT; | |
1496 | if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf, | |
1497 | kiocb->ki_left))) | |
1498 | break; | |
1499 | ret = security_file_permission(file, MAY_READ); | |
1500 | if (unlikely(ret)) | |
1501 | break; | |
1502 | ret = aio_setup_single_vector(kiocb); | |
1503 | if (ret) | |
1504 | break; | |
1505 | ret = -EINVAL; | |
1506 | if (file->f_op->aio_read) | |
1507 | kiocb->ki_retry = aio_rw_vect_retry; | |
1508 | break; | |
1509 | case IOCB_CMD_PWRITE: | |
1510 | ret = -EBADF; | |
1511 | if (unlikely(!(file->f_mode & FMODE_WRITE))) | |
1512 | break; | |
1513 | ret = -EFAULT; | |
1514 | if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf, | |
1515 | kiocb->ki_left))) | |
1516 | break; | |
1517 | ret = security_file_permission(file, MAY_WRITE); | |
1518 | if (unlikely(ret)) | |
1519 | break; | |
1520 | ret = aio_setup_single_vector(kiocb); | |
1521 | if (ret) | |
1522 | break; | |
1523 | ret = -EINVAL; | |
1524 | if (file->f_op->aio_write) | |
1525 | kiocb->ki_retry = aio_rw_vect_retry; | |
1526 | break; | |
1527 | case IOCB_CMD_PREADV: | |
1528 | ret = -EBADF; | |
1529 | if (unlikely(!(file->f_mode & FMODE_READ))) | |
1530 | break; | |
1531 | ret = security_file_permission(file, MAY_READ); | |
1532 | if (unlikely(ret)) | |
1533 | break; | |
1534 | ret = aio_setup_vectored_rw(READ, kiocb, compat); | |
1535 | if (ret) | |
1536 | break; | |
1537 | ret = -EINVAL; | |
1538 | if (file->f_op->aio_read) | |
1539 | kiocb->ki_retry = aio_rw_vect_retry; | |
1540 | break; | |
1541 | case IOCB_CMD_PWRITEV: | |
1542 | ret = -EBADF; | |
1543 | if (unlikely(!(file->f_mode & FMODE_WRITE))) | |
1544 | break; | |
1545 | ret = security_file_permission(file, MAY_WRITE); | |
1546 | if (unlikely(ret)) | |
1547 | break; | |
1548 | ret = aio_setup_vectored_rw(WRITE, kiocb, compat); | |
1549 | if (ret) | |
1550 | break; | |
1551 | ret = -EINVAL; | |
1552 | if (file->f_op->aio_write) | |
1553 | kiocb->ki_retry = aio_rw_vect_retry; | |
1554 | break; | |
1555 | case IOCB_CMD_FDSYNC: | |
1556 | ret = -EINVAL; | |
1557 | if (file->f_op->aio_fsync) | |
1558 | kiocb->ki_retry = aio_fdsync; | |
1559 | break; | |
1560 | case IOCB_CMD_FSYNC: | |
1561 | ret = -EINVAL; | |
1562 | if (file->f_op->aio_fsync) | |
1563 | kiocb->ki_retry = aio_fsync; | |
1564 | break; | |
1565 | default: | |
1566 | dprintk("EINVAL: io_submit: no operation provided\n"); | |
1567 | ret = -EINVAL; | |
1568 | } | |
1569 | ||
1570 | if (!kiocb->ki_retry) | |
1571 | return ret; | |
1572 | ||
1573 | return 0; | |
1574 | } | |
1575 | ||
1576 | static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, | |
1577 | struct iocb *iocb, struct kiocb_batch *batch, | |
1578 | bool compat) | |
1579 | { | |
1580 | struct kiocb *req; | |
1581 | struct file *file; | |
1582 | ssize_t ret; | |
1583 | ||
1584 | /* enforce forwards compatibility on users */ | |
1585 | if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) { | |
1586 | pr_debug("EINVAL: io_submit: reserve field set\n"); | |
1587 | return -EINVAL; | |
1588 | } | |
1589 | ||
1590 | /* prevent overflows */ | |
1591 | if (unlikely( | |
1592 | (iocb->aio_buf != (unsigned long)iocb->aio_buf) || | |
1593 | (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) || | |
1594 | ((ssize_t)iocb->aio_nbytes < 0) | |
1595 | )) { | |
1596 | pr_debug("EINVAL: io_submit: overflow check\n"); | |
1597 | return -EINVAL; | |
1598 | } | |
1599 | ||
1600 | file = fget(iocb->aio_fildes); | |
1601 | if (unlikely(!file)) | |
1602 | return -EBADF; | |
1603 | ||
1604 | req = aio_get_req(ctx, batch); /* returns with 2 references to req */ | |
1605 | if (unlikely(!req)) { | |
1606 | fput(file); | |
1607 | return -EAGAIN; | |
1608 | } | |
1609 | req->ki_filp = file; | |
1610 | if (iocb->aio_flags & IOCB_FLAG_RESFD) { | |
1611 | /* | |
1612 | * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an | |
1613 | * instance of the file* now. The file descriptor must be | |
1614 | * an eventfd() fd, and will be signaled for each completed | |
1615 | * event using the eventfd_signal() function. | |
1616 | */ | |
1617 | req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd); | |
1618 | if (IS_ERR(req->ki_eventfd)) { | |
1619 | ret = PTR_ERR(req->ki_eventfd); | |
1620 | req->ki_eventfd = NULL; | |
1621 | goto out_put_req; | |
1622 | } | |
1623 | } | |
1624 | ||
1625 | ret = put_user(req->ki_key, &user_iocb->aio_key); | |
1626 | if (unlikely(ret)) { | |
1627 | dprintk("EFAULT: aio_key\n"); | |
1628 | goto out_put_req; | |
1629 | } | |
1630 | ||
1631 | req->ki_obj.user = user_iocb; | |
1632 | req->ki_user_data = iocb->aio_data; | |
1633 | req->ki_pos = iocb->aio_offset; | |
1634 | ||
1635 | req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf; | |
1636 | req->ki_left = req->ki_nbytes = iocb->aio_nbytes; | |
1637 | req->ki_opcode = iocb->aio_lio_opcode; | |
1638 | ||
1639 | ret = aio_setup_iocb(req, compat); | |
1640 | ||
1641 | if (ret) | |
1642 | goto out_put_req; | |
1643 | ||
1644 | spin_lock_irq(&ctx->ctx_lock); | |
1645 | /* | |
1646 | * We could have raced with io_destroy() and are currently holding a | |
1647 | * reference to ctx which should be destroyed. We cannot submit IO | |
1648 | * since ctx gets freed as soon as io_submit() puts its reference. The | |
1649 | * check here is reliable: io_destroy() sets ctx->dead before waiting | |
1650 | * for outstanding IO and the barrier between these two is realized by | |
1651 | * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we | |
1652 | * increment ctx->reqs_active before checking for ctx->dead and the | |
1653 | * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we | |
1654 | * don't see ctx->dead set here, io_destroy() waits for our IO to | |
1655 | * finish. | |
1656 | */ | |
1657 | if (ctx->dead) { | |
1658 | spin_unlock_irq(&ctx->ctx_lock); | |
1659 | ret = -EINVAL; | |
1660 | goto out_put_req; | |
1661 | } | |
1662 | aio_run_iocb(req); | |
1663 | if (!list_empty(&ctx->run_list)) { | |
1664 | /* drain the run list */ | |
1665 | while (__aio_run_iocbs(ctx)) | |
1666 | ; | |
1667 | } | |
1668 | spin_unlock_irq(&ctx->ctx_lock); | |
1669 | ||
1670 | aio_put_req(req); /* drop extra ref to req */ | |
1671 | return 0; | |
1672 | ||
1673 | out_put_req: | |
1674 | aio_put_req(req); /* drop extra ref to req */ | |
1675 | aio_put_req(req); /* drop i/o ref to req */ | |
1676 | return ret; | |
1677 | } | |
1678 | ||
1679 | long do_io_submit(aio_context_t ctx_id, long nr, | |
1680 | struct iocb __user *__user *iocbpp, bool compat) | |
1681 | { | |
1682 | struct kioctx *ctx; | |
1683 | long ret = 0; | |
1684 | int i = 0; | |
1685 | struct blk_plug plug; | |
1686 | struct kiocb_batch batch; | |
1687 | ||
1688 | if (unlikely(nr < 0)) | |
1689 | return -EINVAL; | |
1690 | ||
1691 | if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) | |
1692 | nr = LONG_MAX/sizeof(*iocbpp); | |
1693 | ||
1694 | if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) | |
1695 | return -EFAULT; | |
1696 | ||
1697 | ctx = lookup_ioctx(ctx_id); | |
1698 | if (unlikely(!ctx)) { | |
1699 | pr_debug("EINVAL: io_submit: invalid context id\n"); | |
1700 | return -EINVAL; | |
1701 | } | |
1702 | ||
1703 | kiocb_batch_init(&batch, nr); | |
1704 | ||
1705 | blk_start_plug(&plug); | |
1706 | ||
1707 | /* | |
1708 | * AKPM: should this return a partial result if some of the IOs were | |
1709 | * successfully submitted? | |
1710 | */ | |
1711 | for (i=0; i<nr; i++) { | |
1712 | struct iocb __user *user_iocb; | |
1713 | struct iocb tmp; | |
1714 | ||
1715 | if (unlikely(__get_user(user_iocb, iocbpp + i))) { | |
1716 | ret = -EFAULT; | |
1717 | break; | |
1718 | } | |
1719 | ||
1720 | if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) { | |
1721 | ret = -EFAULT; | |
1722 | break; | |
1723 | } | |
1724 | ||
1725 | ret = io_submit_one(ctx, user_iocb, &tmp, &batch, compat); | |
1726 | if (ret) | |
1727 | break; | |
1728 | } | |
1729 | blk_finish_plug(&plug); | |
1730 | ||
1731 | kiocb_batch_free(ctx, &batch); | |
1732 | put_ioctx(ctx); | |
1733 | return i ? i : ret; | |
1734 | } | |
1735 | ||
1736 | /* sys_io_submit: | |
1737 | * Queue the nr iocbs pointed to by iocbpp for processing. Returns | |
1738 | * the number of iocbs queued. May return -EINVAL if the aio_context | |
1739 | * specified by ctx_id is invalid, if nr is < 0, if the iocb at | |
1740 | * *iocbpp[0] is not properly initialized, if the operation specified | |
1741 | * is invalid for the file descriptor in the iocb. May fail with | |
1742 | * -EFAULT if any of the data structures point to invalid data. May | |
1743 | * fail with -EBADF if the file descriptor specified in the first | |
1744 | * iocb is invalid. May fail with -EAGAIN if insufficient resources | |
1745 | * are available to queue any iocbs. Will return 0 if nr is 0. Will | |
1746 | * fail with -ENOSYS if not implemented. | |
1747 | */ | |
1748 | SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, | |
1749 | struct iocb __user * __user *, iocbpp) | |
1750 | { | |
1751 | return do_io_submit(ctx_id, nr, iocbpp, 0); | |
1752 | } | |
1753 | ||
1754 | /* lookup_kiocb | |
1755 | * Finds a given iocb for cancellation. | |
1756 | */ | |
1757 | static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, | |
1758 | u32 key) | |
1759 | { | |
1760 | struct list_head *pos; | |
1761 | ||
1762 | assert_spin_locked(&ctx->ctx_lock); | |
1763 | ||
1764 | /* TODO: use a hash or array, this sucks. */ | |
1765 | list_for_each(pos, &ctx->active_reqs) { | |
1766 | struct kiocb *kiocb = list_kiocb(pos); | |
1767 | if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key) | |
1768 | return kiocb; | |
1769 | } | |
1770 | return NULL; | |
1771 | } | |
1772 | ||
1773 | /* sys_io_cancel: | |
1774 | * Attempts to cancel an iocb previously passed to io_submit. If | |
1775 | * the operation is successfully cancelled, the resulting event is | |
1776 | * copied into the memory pointed to by result without being placed | |
1777 | * into the completion queue and 0 is returned. May fail with | |
1778 | * -EFAULT if any of the data structures pointed to are invalid. | |
1779 | * May fail with -EINVAL if aio_context specified by ctx_id is | |
1780 | * invalid. May fail with -EAGAIN if the iocb specified was not | |
1781 | * cancelled. Will fail with -ENOSYS if not implemented. | |
1782 | */ | |
1783 | SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, | |
1784 | struct io_event __user *, result) | |
1785 | { | |
1786 | int (*cancel)(struct kiocb *iocb, struct io_event *res); | |
1787 | struct kioctx *ctx; | |
1788 | struct kiocb *kiocb; | |
1789 | u32 key; | |
1790 | int ret; | |
1791 | ||
1792 | ret = get_user(key, &iocb->aio_key); | |
1793 | if (unlikely(ret)) | |
1794 | return -EFAULT; | |
1795 | ||
1796 | ctx = lookup_ioctx(ctx_id); | |
1797 | if (unlikely(!ctx)) | |
1798 | return -EINVAL; | |
1799 | ||
1800 | spin_lock_irq(&ctx->ctx_lock); | |
1801 | ret = -EAGAIN; | |
1802 | kiocb = lookup_kiocb(ctx, iocb, key); | |
1803 | if (kiocb && kiocb->ki_cancel) { | |
1804 | cancel = kiocb->ki_cancel; | |
1805 | kiocb->ki_users ++; | |
1806 | kiocbSetCancelled(kiocb); | |
1807 | } else | |
1808 | cancel = NULL; | |
1809 | spin_unlock_irq(&ctx->ctx_lock); | |
1810 | ||
1811 | if (NULL != cancel) { | |
1812 | struct io_event tmp; | |
1813 | pr_debug("calling cancel\n"); | |
1814 | memset(&tmp, 0, sizeof(tmp)); | |
1815 | tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; | |
1816 | tmp.data = kiocb->ki_user_data; | |
1817 | ret = cancel(kiocb, &tmp); | |
1818 | if (!ret) { | |
1819 | /* Cancellation succeeded -- copy the result | |
1820 | * into the user's buffer. | |
1821 | */ | |
1822 | if (copy_to_user(result, &tmp, sizeof(tmp))) | |
1823 | ret = -EFAULT; | |
1824 | } | |
1825 | } else | |
1826 | ret = -EINVAL; | |
1827 | ||
1828 | put_ioctx(ctx); | |
1829 | ||
1830 | return ret; | |
1831 | } | |
1832 | ||
1833 | /* io_getevents: | |
1834 | * Attempts to read at least min_nr events and up to nr events from | |
1835 | * the completion queue for the aio_context specified by ctx_id. If | |
1836 | * it succeeds, the number of read events is returned. May fail with | |
1837 | * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is | |
1838 | * out of range, if timeout is out of range. May fail with -EFAULT | |
1839 | * if any of the memory specified is invalid. May return 0 or | |
1840 | * < min_nr if the timeout specified by timeout has elapsed | |
1841 | * before sufficient events are available, where timeout == NULL | |
1842 | * specifies an infinite timeout. Note that the timeout pointed to by | |
1843 | * timeout is relative and will be updated if not NULL and the | |
1844 | * operation blocks. Will fail with -ENOSYS if not implemented. | |
1845 | */ | |
1846 | SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, | |
1847 | long, min_nr, | |
1848 | long, nr, | |
1849 | struct io_event __user *, events, | |
1850 | struct timespec __user *, timeout) | |
1851 | { | |
1852 | struct kioctx *ioctx = lookup_ioctx(ctx_id); | |
1853 | long ret = -EINVAL; | |
1854 | ||
1855 | if (likely(ioctx)) { | |
1856 | if (likely(min_nr <= nr && min_nr >= 0)) | |
1857 | ret = read_events(ioctx, min_nr, nr, events, timeout); | |
1858 | put_ioctx(ioctx); | |
1859 | } | |
1860 | ||
1861 | asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); | |
1862 | return ret; | |
1863 | } |