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1/*
2 * An async IO implementation for Linux
3 * Written by Benjamin LaHaise <bcrl@kvack.org>
4 *
5 * Implements an efficient asynchronous io interface.
6 *
7 * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
8 *
9 * See ../COPYING for licensing terms.
10 */
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/aio_abi.h>
16#include <linux/module.h>
17#include <linux/syscalls.h>
18#include <linux/backing-dev.h>
19#include <linux/uio.h>
20
21#define DEBUG 0
22
23#include <linux/sched.h>
24#include <linux/fs.h>
25#include <linux/file.h>
26#include <linux/mm.h>
27#include <linux/mman.h>
28#include <linux/mmu_context.h>
29#include <linux/slab.h>
30#include <linux/timer.h>
31#include <linux/aio.h>
32#include <linux/highmem.h>
33#include <linux/workqueue.h>
34#include <linux/security.h>
35#include <linux/eventfd.h>
36#include <linux/blkdev.h>
37#include <linux/compat.h>
38
39#include <asm/kmap_types.h>
40#include <asm/uaccess.h>
41
42#if DEBUG > 1
43#define dprintk printk
44#else
45#define dprintk(x...) do { ; } while (0)
46#endif
47
48/*------ sysctl variables----*/
49static DEFINE_SPINLOCK(aio_nr_lock);
50unsigned long aio_nr; /* current system wide number of aio requests */
51unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
52/*----end sysctl variables---*/
53
54static struct kmem_cache *kiocb_cachep;
55static struct kmem_cache *kioctx_cachep;
56
57static struct workqueue_struct *aio_wq;
58
59/* Used for rare fput completion. */
60static void aio_fput_routine(struct work_struct *);
61static DECLARE_WORK(fput_work, aio_fput_routine);
62
63static DEFINE_SPINLOCK(fput_lock);
64static LIST_HEAD(fput_head);
65
66static void aio_kick_handler(struct work_struct *);
67static 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 */
73static 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
87static void aio_free_ring(struct kioctx *ctx)
88{
89 struct aio_ring_info *info = &ctx->ring_info;
90 long i;
91
92 for (i=0; i<info->nr_pages; i++)
93 put_page(info->ring_pages[i]);
94
95 if (info->mmap_size) {
96 down_write(&ctx->mm->mmap_sem);
97 do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
98 up_write(&ctx->mm->mmap_sem);
99 }
100
101 if (info->ring_pages && info->ring_pages != info->internal_pages)
102 kfree(info->ring_pages);
103 info->ring_pages = NULL;
104 info->nr = 0;
105}
106
107static int aio_setup_ring(struct kioctx *ctx)
108{
109 struct aio_ring *ring;
110 struct aio_ring_info *info = &ctx->ring_info;
111 unsigned nr_events = ctx->max_reqs;
112 unsigned long size;
113 int nr_pages;
114
115 /* Compensate for the ring buffer's head/tail overlap entry */
116 nr_events += 2; /* 1 is required, 2 for good luck */
117
118 size = sizeof(struct aio_ring);
119 size += sizeof(struct io_event) * nr_events;
120 nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
121
122 if (nr_pages < 0)
123 return -EINVAL;
124
125 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
126
127 info->nr = 0;
128 info->ring_pages = info->internal_pages;
129 if (nr_pages > AIO_RING_PAGES) {
130 info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
131 if (!info->ring_pages)
132 return -ENOMEM;
133 }
134
135 info->mmap_size = nr_pages * PAGE_SIZE;
136 dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
137 down_write(&ctx->mm->mmap_sem);
138 info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
139 PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE,
140 0);
141 if (IS_ERR((void *)info->mmap_base)) {
142 up_write(&ctx->mm->mmap_sem);
143 info->mmap_size = 0;
144 aio_free_ring(ctx);
145 return -EAGAIN;
146 }
147
148 dprintk("mmap address: 0x%08lx\n", info->mmap_base);
149 info->nr_pages = get_user_pages(current, ctx->mm,
150 info->mmap_base, nr_pages,
151 1, 0, info->ring_pages, NULL);
152 up_write(&ctx->mm->mmap_sem);
153
154 if (unlikely(info->nr_pages != nr_pages)) {
155 aio_free_ring(ctx);
156 return -EAGAIN;
157 }
158
159 ctx->user_id = info->mmap_base;
160
161 info->nr = nr_events; /* trusted copy */
162
163 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
164 ring->nr = nr_events; /* user copy */
165 ring->id = ctx->user_id;
166 ring->head = ring->tail = 0;
167 ring->magic = AIO_RING_MAGIC;
168 ring->compat_features = AIO_RING_COMPAT_FEATURES;
169 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
170 ring->header_length = sizeof(struct aio_ring);
171 kunmap_atomic(ring, KM_USER0);
172
173 return 0;
174}
175
176
177/* aio_ring_event: returns a pointer to the event at the given index from
178 * kmap_atomic(, km). Release the pointer with put_aio_ring_event();
179 */
180#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
181#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
182#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
183
184#define aio_ring_event(info, nr, km) ({ \
185 unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
186 struct io_event *__event; \
187 __event = kmap_atomic( \
188 (info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
189 __event += pos % AIO_EVENTS_PER_PAGE; \
190 __event; \
191})
192
193#define put_aio_ring_event(event, km) do { \
194 struct io_event *__event = (event); \
195 (void)__event; \
196 kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
197} while(0)
198
199static void ctx_rcu_free(struct rcu_head *head)
200{
201 struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
202 unsigned nr_events = ctx->max_reqs;
203
204 kmem_cache_free(kioctx_cachep, ctx);
205
206 if (nr_events) {
207 spin_lock(&aio_nr_lock);
208 BUG_ON(aio_nr - nr_events > aio_nr);
209 aio_nr -= nr_events;
210 spin_unlock(&aio_nr_lock);
211 }
212}
213
214/* __put_ioctx
215 * Called when the last user of an aio context has gone away,
216 * and the struct needs to be freed.
217 */
218static void __put_ioctx(struct kioctx *ctx)
219{
220 BUG_ON(ctx->reqs_active);
221
222 cancel_delayed_work(&ctx->wq);
223 cancel_work_sync(&ctx->wq.work);
224 aio_free_ring(ctx);
225 mmdrop(ctx->mm);
226 ctx->mm = NULL;
227 pr_debug("__put_ioctx: freeing %p\n", ctx);
228 call_rcu(&ctx->rcu_head, ctx_rcu_free);
229}
230
231static inline void get_ioctx(struct kioctx *kioctx)
232{
233 BUG_ON(atomic_read(&kioctx->users) <= 0);
234 atomic_inc(&kioctx->users);
235}
236
237static inline int try_get_ioctx(struct kioctx *kioctx)
238{
239 return atomic_inc_not_zero(&kioctx->users);
240}
241
242static inline void put_ioctx(struct kioctx *kioctx)
243{
244 BUG_ON(atomic_read(&kioctx->users) <= 0);
245 if (unlikely(atomic_dec_and_test(&kioctx->users)))
246 __put_ioctx(kioctx);
247}
248
249/* ioctx_alloc
250 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
251 */
252static struct kioctx *ioctx_alloc(unsigned nr_events)
253{
254 struct mm_struct *mm;
255 struct kioctx *ctx;
256 int did_sync = 0;
257
258 /* Prevent overflows */
259 if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
260 (nr_events > (0x10000000U / sizeof(struct kiocb)))) {
261 pr_debug("ENOMEM: nr_events too high\n");
262 return ERR_PTR(-EINVAL);
263 }
264
265 if ((unsigned long)nr_events > aio_max_nr)
266 return ERR_PTR(-EAGAIN);
267
268 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
269 if (!ctx)
270 return ERR_PTR(-ENOMEM);
271
272 ctx->max_reqs = nr_events;
273 mm = ctx->mm = current->mm;
274 atomic_inc(&mm->mm_count);
275
276 atomic_set(&ctx->users, 1);
277 spin_lock_init(&ctx->ctx_lock);
278 spin_lock_init(&ctx->ring_info.ring_lock);
279 init_waitqueue_head(&ctx->wait);
280
281 INIT_LIST_HEAD(&ctx->active_reqs);
282 INIT_LIST_HEAD(&ctx->run_list);
283 INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
284
285 if (aio_setup_ring(ctx) < 0)
286 goto out_freectx;
287
288 /* limit the number of system wide aios */
289 do {
290 spin_lock_bh(&aio_nr_lock);
291 if (aio_nr + nr_events > aio_max_nr ||
292 aio_nr + nr_events < aio_nr)
293 ctx->max_reqs = 0;
294 else
295 aio_nr += ctx->max_reqs;
296 spin_unlock_bh(&aio_nr_lock);
297 if (ctx->max_reqs || did_sync)
298 break;
299
300 /* wait for rcu callbacks to have completed before giving up */
301 synchronize_rcu();
302 did_sync = 1;
303 ctx->max_reqs = nr_events;
304 } while (1);
305
306 if (ctx->max_reqs == 0)
307 goto out_cleanup;
308
309 /* now link into global list. */
310 spin_lock(&mm->ioctx_lock);
311 hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
312 spin_unlock(&mm->ioctx_lock);
313
314 dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
315 ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
316 return ctx;
317
318out_cleanup:
319 __put_ioctx(ctx);
320 return ERR_PTR(-EAGAIN);
321
322out_freectx:
323 mmdrop(mm);
324 kmem_cache_free(kioctx_cachep, ctx);
325 ctx = ERR_PTR(-ENOMEM);
326
327 dprintk("aio: error allocating ioctx %p\n", ctx);
328 return ctx;
329}
330
331/* aio_cancel_all
332 * Cancels all outstanding aio requests on an aio context. Used
333 * when the processes owning a context have all exited to encourage
334 * the rapid destruction of the kioctx.
335 */
336static void aio_cancel_all(struct kioctx *ctx)
337{
338 int (*cancel)(struct kiocb *, struct io_event *);
339 struct io_event res;
340 spin_lock_irq(&ctx->ctx_lock);
341 ctx->dead = 1;
342 while (!list_empty(&ctx->active_reqs)) {
343 struct list_head *pos = ctx->active_reqs.next;
344 struct kiocb *iocb = list_kiocb(pos);
345 list_del_init(&iocb->ki_list);
346 cancel = iocb->ki_cancel;
347 kiocbSetCancelled(iocb);
348 if (cancel) {
349 iocb->ki_users++;
350 spin_unlock_irq(&ctx->ctx_lock);
351 cancel(iocb, &res);
352 spin_lock_irq(&ctx->ctx_lock);
353 }
354 }
355 spin_unlock_irq(&ctx->ctx_lock);
356}
357
358static void wait_for_all_aios(struct kioctx *ctx)
359{
360 struct task_struct *tsk = current;
361 DECLARE_WAITQUEUE(wait, tsk);
362
363 spin_lock_irq(&ctx->ctx_lock);
364 if (!ctx->reqs_active)
365 goto out;
366
367 add_wait_queue(&ctx->wait, &wait);
368 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
369 while (ctx->reqs_active) {
370 spin_unlock_irq(&ctx->ctx_lock);
371 io_schedule();
372 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
373 spin_lock_irq(&ctx->ctx_lock);
374 }
375 __set_task_state(tsk, TASK_RUNNING);
376 remove_wait_queue(&ctx->wait, &wait);
377
378out:
379 spin_unlock_irq(&ctx->ctx_lock);
380}
381
382/* wait_on_sync_kiocb:
383 * Waits on the given sync kiocb to complete.
384 */
385ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
386{
387 while (iocb->ki_users) {
388 set_current_state(TASK_UNINTERRUPTIBLE);
389 if (!iocb->ki_users)
390 break;
391 io_schedule();
392 }
393 __set_current_state(TASK_RUNNING);
394 return iocb->ki_user_data;
395}
396EXPORT_SYMBOL(wait_on_sync_kiocb);
397
398/* exit_aio: called when the last user of mm goes away. At this point,
399 * there is no way for any new requests to be submited or any of the
400 * io_* syscalls to be called on the context. However, there may be
401 * outstanding requests which hold references to the context; as they
402 * go away, they will call put_ioctx and release any pinned memory
403 * associated with the request (held via struct page * references).
404 */
405void exit_aio(struct mm_struct *mm)
406{
407 struct kioctx *ctx;
408
409 while (!hlist_empty(&mm->ioctx_list)) {
410 ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
411 hlist_del_rcu(&ctx->list);
412
413 aio_cancel_all(ctx);
414
415 wait_for_all_aios(ctx);
416 /*
417 * Ensure we don't leave the ctx on the aio_wq
418 */
419 cancel_work_sync(&ctx->wq.work);
420
421 if (1 != atomic_read(&ctx->users))
422 printk(KERN_DEBUG
423 "exit_aio:ioctx still alive: %d %d %d\n",
424 atomic_read(&ctx->users), ctx->dead,
425 ctx->reqs_active);
426 put_ioctx(ctx);
427 }
428}
429
430/* aio_get_req
431 * Allocate a slot for an aio request. Increments the users count
432 * of the kioctx so that the kioctx stays around until all requests are
433 * complete. Returns NULL if no requests are free.
434 *
435 * Returns with kiocb->users set to 2. The io submit code path holds
436 * an extra reference while submitting the i/o.
437 * This prevents races between the aio code path referencing the
438 * req (after submitting it) and aio_complete() freeing the req.
439 */
440static struct kiocb *__aio_get_req(struct kioctx *ctx)
441{
442 struct kiocb *req = NULL;
443 struct aio_ring *ring;
444 int okay = 0;
445
446 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
447 if (unlikely(!req))
448 return NULL;
449
450 req->ki_flags = 0;
451 req->ki_users = 2;
452 req->ki_key = 0;
453 req->ki_ctx = ctx;
454 req->ki_cancel = NULL;
455 req->ki_retry = NULL;
456 req->ki_dtor = NULL;
457 req->private = NULL;
458 req->ki_iovec = NULL;
459 INIT_LIST_HEAD(&req->ki_run_list);
460 req->ki_eventfd = NULL;
461
462 /* Check if the completion queue has enough free space to
463 * accept an event from this io.
464 */
465 spin_lock_irq(&ctx->ctx_lock);
466 ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
467 if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
468 list_add(&req->ki_list, &ctx->active_reqs);
469 ctx->reqs_active++;
470 okay = 1;
471 }
472 kunmap_atomic(ring, KM_USER0);
473 spin_unlock_irq(&ctx->ctx_lock);
474
475 if (!okay) {
476 kmem_cache_free(kiocb_cachep, req);
477 req = NULL;
478 }
479
480 return req;
481}
482
483static inline struct kiocb *aio_get_req(struct kioctx *ctx)
484{
485 struct kiocb *req;
486 /* Handle a potential starvation case -- should be exceedingly rare as
487 * requests will be stuck on fput_head only if the aio_fput_routine is
488 * delayed and the requests were the last user of the struct file.
489 */
490 req = __aio_get_req(ctx);
491 if (unlikely(NULL == req)) {
492 aio_fput_routine(NULL);
493 req = __aio_get_req(ctx);
494 }
495 return req;
496}
497
498static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
499{
500 assert_spin_locked(&ctx->ctx_lock);
501
502 if (req->ki_eventfd != NULL)
503 eventfd_ctx_put(req->ki_eventfd);
504 if (req->ki_dtor)
505 req->ki_dtor(req);
506 if (req->ki_iovec != &req->ki_inline_vec)
507 kfree(req->ki_iovec);
508 kmem_cache_free(kiocb_cachep, req);
509 ctx->reqs_active--;
510
511 if (unlikely(!ctx->reqs_active && ctx->dead))
512 wake_up_all(&ctx->wait);
513}
514
515static void aio_fput_routine(struct work_struct *data)
516{
517 spin_lock_irq(&fput_lock);
518 while (likely(!list_empty(&fput_head))) {
519 struct kiocb *req = list_kiocb(fput_head.next);
520 struct kioctx *ctx = req->ki_ctx;
521
522 list_del(&req->ki_list);
523 spin_unlock_irq(&fput_lock);
524
525 /* Complete the fput(s) */
526 if (req->ki_filp != NULL)
527 fput(req->ki_filp);
528
529 /* Link the iocb into the context's free list */
530 spin_lock_irq(&ctx->ctx_lock);
531 really_put_req(ctx, req);
532 spin_unlock_irq(&ctx->ctx_lock);
533
534 put_ioctx(ctx);
535 spin_lock_irq(&fput_lock);
536 }
537 spin_unlock_irq(&fput_lock);
538}
539
540/* __aio_put_req
541 * Returns true if this put was the last user of the request.
542 */
543static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
544{
545 dprintk(KERN_DEBUG "aio_put(%p): f_count=%ld\n",
546 req, atomic_long_read(&req->ki_filp->f_count));
547
548 assert_spin_locked(&ctx->ctx_lock);
549
550 req->ki_users--;
551 BUG_ON(req->ki_users < 0);
552 if (likely(req->ki_users))
553 return 0;
554 list_del(&req->ki_list); /* remove from active_reqs */
555 req->ki_cancel = NULL;
556 req->ki_retry = NULL;
557
558 /*
559 * Try to optimize the aio and eventfd file* puts, by avoiding to
560 * schedule work in case it is not final fput() time. In normal cases,
561 * we would not be holding the last reference to the file*, so
562 * this function will be executed w/out any aio kthread wakeup.
563 */
564 if (unlikely(!fput_atomic(req->ki_filp))) {
565 get_ioctx(ctx);
566 spin_lock(&fput_lock);
567 list_add(&req->ki_list, &fput_head);
568 spin_unlock(&fput_lock);
569 schedule_work(&fput_work);
570 } else {
571 req->ki_filp = NULL;
572 really_put_req(ctx, req);
573 }
574 return 1;
575}
576
577/* aio_put_req
578 * Returns true if this put was the last user of the kiocb,
579 * false if the request is still in use.
580 */
581int aio_put_req(struct kiocb *req)
582{
583 struct kioctx *ctx = req->ki_ctx;
584 int ret;
585 spin_lock_irq(&ctx->ctx_lock);
586 ret = __aio_put_req(ctx, req);
587 spin_unlock_irq(&ctx->ctx_lock);
588 return ret;
589}
590EXPORT_SYMBOL(aio_put_req);
591
592static struct kioctx *lookup_ioctx(unsigned long ctx_id)
593{
594 struct mm_struct *mm = current->mm;
595 struct kioctx *ctx, *ret = NULL;
596 struct hlist_node *n;
597
598 rcu_read_lock();
599
600 hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) {
601 /*
602 * RCU protects us against accessing freed memory but
603 * we have to be careful not to get a reference when the
604 * reference count already dropped to 0 (ctx->dead test
605 * is unreliable because of races).
606 */
607 if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
608 ret = ctx;
609 break;
610 }
611 }
612
613 rcu_read_unlock();
614 return ret;
615}
616
617/*
618 * Queue up a kiocb to be retried. Assumes that the kiocb
619 * has already been marked as kicked, and places it on
620 * the retry run list for the corresponding ioctx, if it
621 * isn't already queued. Returns 1 if it actually queued
622 * the kiocb (to tell the caller to activate the work
623 * queue to process it), or 0, if it found that it was
624 * already queued.
625 */
626static inline int __queue_kicked_iocb(struct kiocb *iocb)
627{
628 struct kioctx *ctx = iocb->ki_ctx;
629
630 assert_spin_locked(&ctx->ctx_lock);
631
632 if (list_empty(&iocb->ki_run_list)) {
633 list_add_tail(&iocb->ki_run_list,
634 &ctx->run_list);
635 return 1;
636 }
637 return 0;
638}
639
640/* aio_run_iocb
641 * This is the core aio execution routine. It is
642 * invoked both for initial i/o submission and
643 * subsequent retries via the aio_kick_handler.
644 * Expects to be invoked with iocb->ki_ctx->lock
645 * already held. The lock is released and reacquired
646 * as needed during processing.
647 *
648 * Calls the iocb retry method (already setup for the
649 * iocb on initial submission) for operation specific
650 * handling, but takes care of most of common retry
651 * execution details for a given iocb. The retry method
652 * needs to be non-blocking as far as possible, to avoid
653 * holding up other iocbs waiting to be serviced by the
654 * retry kernel thread.
655 *
656 * The trickier parts in this code have to do with
657 * ensuring that only one retry instance is in progress
658 * for a given iocb at any time. Providing that guarantee
659 * simplifies the coding of individual aio operations as
660 * it avoids various potential races.
661 */
662static ssize_t aio_run_iocb(struct kiocb *iocb)
663{
664 struct kioctx *ctx = iocb->ki_ctx;
665 ssize_t (*retry)(struct kiocb *);
666 ssize_t ret;
667
668 if (!(retry = iocb->ki_retry)) {
669 printk("aio_run_iocb: iocb->ki_retry = NULL\n");
670 return 0;
671 }
672
673 /*
674 * We don't want the next retry iteration for this
675 * operation to start until this one has returned and
676 * updated the iocb state. However, wait_queue functions
677 * can trigger a kick_iocb from interrupt context in the
678 * meantime, indicating that data is available for the next
679 * iteration. We want to remember that and enable the
680 * next retry iteration _after_ we are through with
681 * this one.
682 *
683 * So, in order to be able to register a "kick", but
684 * prevent it from being queued now, we clear the kick
685 * flag, but make the kick code *think* that the iocb is
686 * still on the run list until we are actually done.
687 * When we are done with this iteration, we check if
688 * the iocb was kicked in the meantime and if so, queue
689 * it up afresh.
690 */
691
692 kiocbClearKicked(iocb);
693
694 /*
695 * This is so that aio_complete knows it doesn't need to
696 * pull the iocb off the run list (We can't just call
697 * INIT_LIST_HEAD because we don't want a kick_iocb to
698 * queue this on the run list yet)
699 */
700 iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
701 spin_unlock_irq(&ctx->ctx_lock);
702
703 /* Quit retrying if the i/o has been cancelled */
704 if (kiocbIsCancelled(iocb)) {
705 ret = -EINTR;
706 aio_complete(iocb, ret, 0);
707 /* must not access the iocb after this */
708 goto out;
709 }
710
711 /*
712 * Now we are all set to call the retry method in async
713 * context.
714 */
715 ret = retry(iocb);
716
717 if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
718 /*
719 * There's no easy way to restart the syscall since other AIO's
720 * may be already running. Just fail this IO with EINTR.
721 */
722 if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
723 ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK))
724 ret = -EINTR;
725 aio_complete(iocb, ret, 0);
726 }
727out:
728 spin_lock_irq(&ctx->ctx_lock);
729
730 if (-EIOCBRETRY == ret) {
731 /*
732 * OK, now that we are done with this iteration
733 * and know that there is more left to go,
734 * this is where we let go so that a subsequent
735 * "kick" can start the next iteration
736 */
737
738 /* will make __queue_kicked_iocb succeed from here on */
739 INIT_LIST_HEAD(&iocb->ki_run_list);
740 /* we must queue the next iteration ourselves, if it
741 * has already been kicked */
742 if (kiocbIsKicked(iocb)) {
743 __queue_kicked_iocb(iocb);
744
745 /*
746 * __queue_kicked_iocb will always return 1 here, because
747 * iocb->ki_run_list is empty at this point so it should
748 * be safe to unconditionally queue the context into the
749 * work queue.
750 */
751 aio_queue_work(ctx);
752 }
753 }
754 return ret;
755}
756
757/*
758 * __aio_run_iocbs:
759 * Process all pending retries queued on the ioctx
760 * run list.
761 * Assumes it is operating within the aio issuer's mm
762 * context.
763 */
764static int __aio_run_iocbs(struct kioctx *ctx)
765{
766 struct kiocb *iocb;
767 struct list_head run_list;
768
769 assert_spin_locked(&ctx->ctx_lock);
770
771 list_replace_init(&ctx->run_list, &run_list);
772 while (!list_empty(&run_list)) {
773 iocb = list_entry(run_list.next, struct kiocb,
774 ki_run_list);
775 list_del(&iocb->ki_run_list);
776 /*
777 * Hold an extra reference while retrying i/o.
778 */
779 iocb->ki_users++; /* grab extra reference */
780 aio_run_iocb(iocb);
781 __aio_put_req(ctx, iocb);
782 }
783 if (!list_empty(&ctx->run_list))
784 return 1;
785 return 0;
786}
787
788static void aio_queue_work(struct kioctx * ctx)
789{
790 unsigned long timeout;
791 /*
792 * if someone is waiting, get the work started right
793 * away, otherwise, use a longer delay
794 */
795 smp_mb();
796 if (waitqueue_active(&ctx->wait))
797 timeout = 1;
798 else
799 timeout = HZ/10;
800 queue_delayed_work(aio_wq, &ctx->wq, timeout);
801}
802
803/*
804 * aio_run_all_iocbs:
805 * Process all pending retries queued on the ioctx
806 * run list, and keep running them until the list
807 * stays empty.
808 * Assumes it is operating within the aio issuer's mm context.
809 */
810static inline void aio_run_all_iocbs(struct kioctx *ctx)
811{
812 spin_lock_irq(&ctx->ctx_lock);
813 while (__aio_run_iocbs(ctx))
814 ;
815 spin_unlock_irq(&ctx->ctx_lock);
816}
817
818/*
819 * aio_kick_handler:
820 * Work queue handler triggered to process pending
821 * retries on an ioctx. Takes on the aio issuer's
822 * mm context before running the iocbs, so that
823 * copy_xxx_user operates on the issuer's address
824 * space.
825 * Run on aiod's context.
826 */
827static void aio_kick_handler(struct work_struct *work)
828{
829 struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
830 mm_segment_t oldfs = get_fs();
831 struct mm_struct *mm;
832 int requeue;
833
834 set_fs(USER_DS);
835 use_mm(ctx->mm);
836 spin_lock_irq(&ctx->ctx_lock);
837 requeue =__aio_run_iocbs(ctx);
838 mm = ctx->mm;
839 spin_unlock_irq(&ctx->ctx_lock);
840 unuse_mm(mm);
841 set_fs(oldfs);
842 /*
843 * we're in a worker thread already, don't use queue_delayed_work,
844 */
845 if (requeue)
846 queue_delayed_work(aio_wq, &ctx->wq, 0);
847}
848
849
850/*
851 * Called by kick_iocb to queue the kiocb for retry
852 * and if required activate the aio work queue to process
853 * it
854 */
855static void try_queue_kicked_iocb(struct kiocb *iocb)
856{
857 struct kioctx *ctx = iocb->ki_ctx;
858 unsigned long flags;
859 int run = 0;
860
861 spin_lock_irqsave(&ctx->ctx_lock, flags);
862 /* set this inside the lock so that we can't race with aio_run_iocb()
863 * testing it and putting the iocb on the run list under the lock */
864 if (!kiocbTryKick(iocb))
865 run = __queue_kicked_iocb(iocb);
866 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
867 if (run)
868 aio_queue_work(ctx);
869}
870
871/*
872 * kick_iocb:
873 * Called typically from a wait queue callback context
874 * to trigger a retry of the iocb.
875 * The retry is usually executed by aio workqueue
876 * threads (See aio_kick_handler).
877 */
878void kick_iocb(struct kiocb *iocb)
879{
880 /* sync iocbs are easy: they can only ever be executing from a
881 * single context. */
882 if (is_sync_kiocb(iocb)) {
883 kiocbSetKicked(iocb);
884 wake_up_process(iocb->ki_obj.tsk);
885 return;
886 }
887
888 try_queue_kicked_iocb(iocb);
889}
890EXPORT_SYMBOL(kick_iocb);
891
892/* aio_complete
893 * Called when the io request on the given iocb is complete.
894 * Returns true if this is the last user of the request. The
895 * only other user of the request can be the cancellation code.
896 */
897int aio_complete(struct kiocb *iocb, long res, long res2)
898{
899 struct kioctx *ctx = iocb->ki_ctx;
900 struct aio_ring_info *info;
901 struct aio_ring *ring;
902 struct io_event *event;
903 unsigned long flags;
904 unsigned long tail;
905 int ret;
906
907 /*
908 * Special case handling for sync iocbs:
909 * - events go directly into the iocb for fast handling
910 * - the sync task with the iocb in its stack holds the single iocb
911 * ref, no other paths have a way to get another ref
912 * - the sync task helpfully left a reference to itself in the iocb
913 */
914 if (is_sync_kiocb(iocb)) {
915 BUG_ON(iocb->ki_users != 1);
916 iocb->ki_user_data = res;
917 iocb->ki_users = 0;
918 wake_up_process(iocb->ki_obj.tsk);
919 return 1;
920 }
921
922 info = &ctx->ring_info;
923
924 /* add a completion event to the ring buffer.
925 * must be done holding ctx->ctx_lock to prevent
926 * other code from messing with the tail
927 * pointer since we might be called from irq
928 * context.
929 */
930 spin_lock_irqsave(&ctx->ctx_lock, flags);
931
932 if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
933 list_del_init(&iocb->ki_run_list);
934
935 /*
936 * cancelled requests don't get events, userland was given one
937 * when the event got cancelled.
938 */
939 if (kiocbIsCancelled(iocb))
940 goto put_rq;
941
942 ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
943
944 tail = info->tail;
945 event = aio_ring_event(info, tail, KM_IRQ0);
946 if (++tail >= info->nr)
947 tail = 0;
948
949 event->obj = (u64)(unsigned long)iocb->ki_obj.user;
950 event->data = iocb->ki_user_data;
951 event->res = res;
952 event->res2 = res2;
953
954 dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
955 ctx, tail, iocb, iocb->ki_obj.user, iocb->ki_user_data,
956 res, res2);
957
958 /* after flagging the request as done, we
959 * must never even look at it again
960 */
961 smp_wmb(); /* make event visible before updating tail */
962
963 info->tail = tail;
964 ring->tail = tail;
965
966 put_aio_ring_event(event, KM_IRQ0);
967 kunmap_atomic(ring, KM_IRQ1);
968
969 pr_debug("added to ring %p at [%lu]\n", iocb, tail);
970
971 /*
972 * Check if the user asked us to deliver the result through an
973 * eventfd. The eventfd_signal() function is safe to be called
974 * from IRQ context.
975 */
976 if (iocb->ki_eventfd != NULL)
977 eventfd_signal(iocb->ki_eventfd, 1);
978
979put_rq:
980 /* everything turned out well, dispose of the aiocb. */
981 ret = __aio_put_req(ctx, iocb);
982
983 /*
984 * We have to order our ring_info tail store above and test
985 * of the wait list below outside the wait lock. This is
986 * like in wake_up_bit() where clearing a bit has to be
987 * ordered with the unlocked test.
988 */
989 smp_mb();
990
991 if (waitqueue_active(&ctx->wait))
992 wake_up(&ctx->wait);
993
994 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
995 return ret;
996}
997EXPORT_SYMBOL(aio_complete);
998
999/* aio_read_evt
1000 * Pull an event off of the ioctx's event ring. Returns the number of
1001 * events fetched (0 or 1 ;-)
1002 * FIXME: make this use cmpxchg.
1003 * TODO: make the ringbuffer user mmap()able (requires FIXME).
1004 */
1005static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
1006{
1007 struct aio_ring_info *info = &ioctx->ring_info;
1008 struct aio_ring *ring;
1009 unsigned long head;
1010 int ret = 0;
1011
1012 ring = kmap_atomic(info->ring_pages[0], KM_USER0);
1013 dprintk("in aio_read_evt h%lu t%lu m%lu\n",
1014 (unsigned long)ring->head, (unsigned long)ring->tail,
1015 (unsigned long)ring->nr);
1016
1017 if (ring->head == ring->tail)
1018 goto out;
1019
1020 spin_lock(&info->ring_lock);
1021
1022 head = ring->head % info->nr;
1023 if (head != ring->tail) {
1024 struct io_event *evp = aio_ring_event(info, head, KM_USER1);
1025 *ent = *evp;
1026 head = (head + 1) % info->nr;
1027 smp_mb(); /* finish reading the event before updatng the head */
1028 ring->head = head;
1029 ret = 1;
1030 put_aio_ring_event(evp, KM_USER1);
1031 }
1032 spin_unlock(&info->ring_lock);
1033
1034out:
1035 kunmap_atomic(ring, KM_USER0);
1036 dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
1037 (unsigned long)ring->head, (unsigned long)ring->tail);
1038 return ret;
1039}
1040
1041struct aio_timeout {
1042 struct timer_list timer;
1043 int timed_out;
1044 struct task_struct *p;
1045};
1046
1047static void timeout_func(unsigned long data)
1048{
1049 struct aio_timeout *to = (struct aio_timeout *)data;
1050
1051 to->timed_out = 1;
1052 wake_up_process(to->p);
1053}
1054
1055static inline void init_timeout(struct aio_timeout *to)
1056{
1057 setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
1058 to->timed_out = 0;
1059 to->p = current;
1060}
1061
1062static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
1063 const struct timespec *ts)
1064{
1065 to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
1066 if (time_after(to->timer.expires, jiffies))
1067 add_timer(&to->timer);
1068 else
1069 to->timed_out = 1;
1070}
1071
1072static inline void clear_timeout(struct aio_timeout *to)
1073{
1074 del_singleshot_timer_sync(&to->timer);
1075}
1076
1077static int read_events(struct kioctx *ctx,
1078 long min_nr, long nr,
1079 struct io_event __user *event,
1080 struct timespec __user *timeout)
1081{
1082 long start_jiffies = jiffies;
1083 struct task_struct *tsk = current;
1084 DECLARE_WAITQUEUE(wait, tsk);
1085 int ret;
1086 int i = 0;
1087 struct io_event ent;
1088 struct aio_timeout to;
1089 int retry = 0;
1090
1091 /* needed to zero any padding within an entry (there shouldn't be
1092 * any, but C is fun!
1093 */
1094 memset(&ent, 0, sizeof(ent));
1095retry:
1096 ret = 0;
1097 while (likely(i < nr)) {
1098 ret = aio_read_evt(ctx, &ent);
1099 if (unlikely(ret <= 0))
1100 break;
1101
1102 dprintk("read event: %Lx %Lx %Lx %Lx\n",
1103 ent.data, ent.obj, ent.res, ent.res2);
1104
1105 /* Could we split the check in two? */
1106 ret = -EFAULT;
1107 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1108 dprintk("aio: lost an event due to EFAULT.\n");
1109 break;
1110 }
1111 ret = 0;
1112
1113 /* Good, event copied to userland, update counts. */
1114 event ++;
1115 i ++;
1116 }
1117
1118 if (min_nr <= i)
1119 return i;
1120 if (ret)
1121 return ret;
1122
1123 /* End fast path */
1124
1125 /* racey check, but it gets redone */
1126 if (!retry && unlikely(!list_empty(&ctx->run_list))) {
1127 retry = 1;
1128 aio_run_all_iocbs(ctx);
1129 goto retry;
1130 }
1131
1132 init_timeout(&to);
1133 if (timeout) {
1134 struct timespec ts;
1135 ret = -EFAULT;
1136 if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
1137 goto out;
1138
1139 set_timeout(start_jiffies, &to, &ts);
1140 }
1141
1142 while (likely(i < nr)) {
1143 add_wait_queue_exclusive(&ctx->wait, &wait);
1144 do {
1145 set_task_state(tsk, TASK_INTERRUPTIBLE);
1146 ret = aio_read_evt(ctx, &ent);
1147 if (ret)
1148 break;
1149 if (min_nr <= i)
1150 break;
1151 if (unlikely(ctx->dead)) {
1152 ret = -EINVAL;
1153 break;
1154 }
1155 if (to.timed_out) /* Only check after read evt */
1156 break;
1157 /* Try to only show up in io wait if there are ops
1158 * in flight */
1159 if (ctx->reqs_active)
1160 io_schedule();
1161 else
1162 schedule();
1163 if (signal_pending(tsk)) {
1164 ret = -EINTR;
1165 break;
1166 }
1167 /*ret = aio_read_evt(ctx, &ent);*/
1168 } while (1) ;
1169
1170 set_task_state(tsk, TASK_RUNNING);
1171 remove_wait_queue(&ctx->wait, &wait);
1172
1173 if (unlikely(ret <= 0))
1174 break;
1175
1176 ret = -EFAULT;
1177 if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
1178 dprintk("aio: lost an event due to EFAULT.\n");
1179 break;
1180 }
1181
1182 /* Good, event copied to userland, update counts. */
1183 event ++;
1184 i ++;
1185 }
1186
1187 if (timeout)
1188 clear_timeout(&to);
1189out:
1190 destroy_timer_on_stack(&to.timer);
1191 return i ? i : ret;
1192}
1193
1194/* Take an ioctx and remove it from the list of ioctx's. Protects
1195 * against races with itself via ->dead.
1196 */
1197static void io_destroy(struct kioctx *ioctx)
1198{
1199 struct mm_struct *mm = current->mm;
1200 int was_dead;
1201
1202 /* delete the entry from the list is someone else hasn't already */
1203 spin_lock(&mm->ioctx_lock);
1204 was_dead = ioctx->dead;
1205 ioctx->dead = 1;
1206 hlist_del_rcu(&ioctx->list);
1207 spin_unlock(&mm->ioctx_lock);
1208
1209 dprintk("aio_release(%p)\n", ioctx);
1210 if (likely(!was_dead))
1211 put_ioctx(ioctx); /* twice for the list */
1212
1213 aio_cancel_all(ioctx);
1214 wait_for_all_aios(ioctx);
1215
1216 /*
1217 * Wake up any waiters. The setting of ctx->dead must be seen
1218 * by other CPUs at this point. Right now, we rely on the
1219 * locking done by the above calls to ensure this consistency.
1220 */
1221 wake_up_all(&ioctx->wait);
1222 put_ioctx(ioctx); /* once for the lookup */
1223}
1224
1225/* sys_io_setup:
1226 * Create an aio_context capable of receiving at least nr_events.
1227 * ctxp must not point to an aio_context that already exists, and
1228 * must be initialized to 0 prior to the call. On successful
1229 * creation of the aio_context, *ctxp is filled in with the resulting
1230 * handle. May fail with -EINVAL if *ctxp is not initialized,
1231 * if the specified nr_events exceeds internal limits. May fail
1232 * with -EAGAIN if the specified nr_events exceeds the user's limit
1233 * of available events. May fail with -ENOMEM if insufficient kernel
1234 * resources are available. May fail with -EFAULT if an invalid
1235 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1236 * implemented.
1237 */
1238SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1239{
1240 struct kioctx *ioctx = NULL;
1241 unsigned long ctx;
1242 long ret;
1243
1244 ret = get_user(ctx, ctxp);
1245 if (unlikely(ret))
1246 goto out;
1247
1248 ret = -EINVAL;
1249 if (unlikely(ctx || nr_events == 0)) {
1250 pr_debug("EINVAL: io_setup: ctx %lu nr_events %u\n",
1251 ctx, nr_events);
1252 goto out;
1253 }
1254
1255 ioctx = ioctx_alloc(nr_events);
1256 ret = PTR_ERR(ioctx);
1257 if (!IS_ERR(ioctx)) {
1258 ret = put_user(ioctx->user_id, ctxp);
1259 if (!ret)
1260 return 0;
1261
1262 get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
1263 io_destroy(ioctx);
1264 }
1265
1266out:
1267 return ret;
1268}
1269
1270/* sys_io_destroy:
1271 * Destroy the aio_context specified. May cancel any outstanding
1272 * AIOs and block on completion. Will fail with -ENOSYS if not
1273 * implemented. May fail with -EINVAL if the context pointed to
1274 * is invalid.
1275 */
1276SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1277{
1278 struct kioctx *ioctx = lookup_ioctx(ctx);
1279 if (likely(NULL != ioctx)) {
1280 io_destroy(ioctx);
1281 return 0;
1282 }
1283 pr_debug("EINVAL: io_destroy: invalid context id\n");
1284 return -EINVAL;
1285}
1286
1287static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
1288{
1289 struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
1290
1291 BUG_ON(ret <= 0);
1292
1293 while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
1294 ssize_t this = min((ssize_t)iov->iov_len, ret);
1295 iov->iov_base += this;
1296 iov->iov_len -= this;
1297 iocb->ki_left -= this;
1298 ret -= this;
1299 if (iov->iov_len == 0) {
1300 iocb->ki_cur_seg++;
1301 iov++;
1302 }
1303 }
1304
1305 /* the caller should not have done more io than what fit in
1306 * the remaining iovecs */
1307 BUG_ON(ret > 0 && iocb->ki_left == 0);
1308}
1309
1310static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
1311{
1312 struct file *file = iocb->ki_filp;
1313 struct address_space *mapping = file->f_mapping;
1314 struct inode *inode = mapping->host;
1315 ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
1316 unsigned long, loff_t);
1317 ssize_t ret = 0;
1318 unsigned short opcode;
1319
1320 if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
1321 (iocb->ki_opcode == IOCB_CMD_PREAD)) {
1322 rw_op = file->f_op->aio_read;
1323 opcode = IOCB_CMD_PREADV;
1324 } else {
1325 rw_op = file->f_op->aio_write;
1326 opcode = IOCB_CMD_PWRITEV;
1327 }
1328
1329 /* This matches the pread()/pwrite() logic */
1330 if (iocb->ki_pos < 0)
1331 return -EINVAL;
1332
1333 do {
1334 ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
1335 iocb->ki_nr_segs - iocb->ki_cur_seg,
1336 iocb->ki_pos);
1337 if (ret > 0)
1338 aio_advance_iovec(iocb, ret);
1339
1340 /* retry all partial writes. retry partial reads as long as its a
1341 * regular file. */
1342 } while (ret > 0 && iocb->ki_left > 0 &&
1343 (opcode == IOCB_CMD_PWRITEV ||
1344 (!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
1345
1346 /* This means we must have transferred all that we could */
1347 /* No need to retry anymore */
1348 if ((ret == 0) || (iocb->ki_left == 0))
1349 ret = iocb->ki_nbytes - iocb->ki_left;
1350
1351 /* If we managed to write some out we return that, rather than
1352 * the eventual error. */
1353 if (opcode == IOCB_CMD_PWRITEV
1354 && ret < 0 && ret != -EIOCBQUEUED && ret != -EIOCBRETRY
1355 && iocb->ki_nbytes - iocb->ki_left)
1356 ret = iocb->ki_nbytes - iocb->ki_left;
1357
1358 return ret;
1359}
1360
1361static ssize_t aio_fdsync(struct kiocb *iocb)
1362{
1363 struct file *file = iocb->ki_filp;
1364 ssize_t ret = -EINVAL;
1365
1366 if (file->f_op->aio_fsync)
1367 ret = file->f_op->aio_fsync(iocb, 1);
1368 return ret;
1369}
1370
1371static ssize_t aio_fsync(struct kiocb *iocb)
1372{
1373 struct file *file = iocb->ki_filp;
1374 ssize_t ret = -EINVAL;
1375
1376 if (file->f_op->aio_fsync)
1377 ret = file->f_op->aio_fsync(iocb, 0);
1378 return ret;
1379}
1380
1381static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
1382{
1383 ssize_t ret;
1384
1385#ifdef CONFIG_COMPAT
1386 if (compat)
1387 ret = compat_rw_copy_check_uvector(type,
1388 (struct compat_iovec __user *)kiocb->ki_buf,
1389 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
1390 &kiocb->ki_iovec);
1391 else
1392#endif
1393 ret = rw_copy_check_uvector(type,
1394 (struct iovec __user *)kiocb->ki_buf,
1395 kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
1396 &kiocb->ki_iovec);
1397 if (ret < 0)
1398 goto out;
1399
1400 kiocb->ki_nr_segs = kiocb->ki_nbytes;
1401 kiocb->ki_cur_seg = 0;
1402 /* ki_nbytes/left now reflect bytes instead of segs */
1403 kiocb->ki_nbytes = ret;
1404 kiocb->ki_left = ret;
1405
1406 ret = 0;
1407out:
1408 return ret;
1409}
1410
1411static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
1412{
1413 kiocb->ki_iovec = &kiocb->ki_inline_vec;
1414 kiocb->ki_iovec->iov_base = kiocb->ki_buf;
1415 kiocb->ki_iovec->iov_len = kiocb->ki_left;
1416 kiocb->ki_nr_segs = 1;
1417 kiocb->ki_cur_seg = 0;
1418 return 0;
1419}
1420
1421/*
1422 * aio_setup_iocb:
1423 * Performs the initial checks and aio retry method
1424 * setup for the kiocb at the time of io submission.
1425 */
1426static ssize_t aio_setup_iocb(struct kiocb *kiocb, bool compat)
1427{
1428 struct file *file = kiocb->ki_filp;
1429 ssize_t ret = 0;
1430
1431 switch (kiocb->ki_opcode) {
1432 case IOCB_CMD_PREAD:
1433 ret = -EBADF;
1434 if (unlikely(!(file->f_mode & FMODE_READ)))
1435 break;
1436 ret = -EFAULT;
1437 if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
1438 kiocb->ki_left)))
1439 break;
1440 ret = security_file_permission(file, MAY_READ);
1441 if (unlikely(ret))
1442 break;
1443 ret = aio_setup_single_vector(kiocb);
1444 if (ret)
1445 break;
1446 ret = -EINVAL;
1447 if (file->f_op->aio_read)
1448 kiocb->ki_retry = aio_rw_vect_retry;
1449 break;
1450 case IOCB_CMD_PWRITE:
1451 ret = -EBADF;
1452 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1453 break;
1454 ret = -EFAULT;
1455 if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
1456 kiocb->ki_left)))
1457 break;
1458 ret = security_file_permission(file, MAY_WRITE);
1459 if (unlikely(ret))
1460 break;
1461 ret = aio_setup_single_vector(kiocb);
1462 if (ret)
1463 break;
1464 ret = -EINVAL;
1465 if (file->f_op->aio_write)
1466 kiocb->ki_retry = aio_rw_vect_retry;
1467 break;
1468 case IOCB_CMD_PREADV:
1469 ret = -EBADF;
1470 if (unlikely(!(file->f_mode & FMODE_READ)))
1471 break;
1472 ret = security_file_permission(file, MAY_READ);
1473 if (unlikely(ret))
1474 break;
1475 ret = aio_setup_vectored_rw(READ, kiocb, compat);
1476 if (ret)
1477 break;
1478 ret = -EINVAL;
1479 if (file->f_op->aio_read)
1480 kiocb->ki_retry = aio_rw_vect_retry;
1481 break;
1482 case IOCB_CMD_PWRITEV:
1483 ret = -EBADF;
1484 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1485 break;
1486 ret = security_file_permission(file, MAY_WRITE);
1487 if (unlikely(ret))
1488 break;
1489 ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
1490 if (ret)
1491 break;
1492 ret = -EINVAL;
1493 if (file->f_op->aio_write)
1494 kiocb->ki_retry = aio_rw_vect_retry;
1495 break;
1496 case IOCB_CMD_FDSYNC:
1497 ret = -EINVAL;
1498 if (file->f_op->aio_fsync)
1499 kiocb->ki_retry = aio_fdsync;
1500 break;
1501 case IOCB_CMD_FSYNC:
1502 ret = -EINVAL;
1503 if (file->f_op->aio_fsync)
1504 kiocb->ki_retry = aio_fsync;
1505 break;
1506 default:
1507 dprintk("EINVAL: io_submit: no operation provided\n");
1508 ret = -EINVAL;
1509 }
1510
1511 if (!kiocb->ki_retry)
1512 return ret;
1513
1514 return 0;
1515}
1516
1517static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1518 struct iocb *iocb, bool compat)
1519{
1520 struct kiocb *req;
1521 struct file *file;
1522 ssize_t ret;
1523
1524 /* enforce forwards compatibility on users */
1525 if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
1526 pr_debug("EINVAL: io_submit: reserve field set\n");
1527 return -EINVAL;
1528 }
1529
1530 /* prevent overflows */
1531 if (unlikely(
1532 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1533 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1534 ((ssize_t)iocb->aio_nbytes < 0)
1535 )) {
1536 pr_debug("EINVAL: io_submit: overflow check\n");
1537 return -EINVAL;
1538 }
1539
1540 file = fget(iocb->aio_fildes);
1541 if (unlikely(!file))
1542 return -EBADF;
1543
1544 req = aio_get_req(ctx); /* returns with 2 references to req */
1545 if (unlikely(!req)) {
1546 fput(file);
1547 return -EAGAIN;
1548 }
1549 req->ki_filp = file;
1550 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1551 /*
1552 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1553 * instance of the file* now. The file descriptor must be
1554 * an eventfd() fd, and will be signaled for each completed
1555 * event using the eventfd_signal() function.
1556 */
1557 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
1558 if (IS_ERR(req->ki_eventfd)) {
1559 ret = PTR_ERR(req->ki_eventfd);
1560 req->ki_eventfd = NULL;
1561 goto out_put_req;
1562 }
1563 }
1564
1565 ret = put_user(req->ki_key, &user_iocb->aio_key);
1566 if (unlikely(ret)) {
1567 dprintk("EFAULT: aio_key\n");
1568 goto out_put_req;
1569 }
1570
1571 req->ki_obj.user = user_iocb;
1572 req->ki_user_data = iocb->aio_data;
1573 req->ki_pos = iocb->aio_offset;
1574
1575 req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
1576 req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
1577 req->ki_opcode = iocb->aio_lio_opcode;
1578
1579 ret = aio_setup_iocb(req, compat);
1580
1581 if (ret)
1582 goto out_put_req;
1583
1584 spin_lock_irq(&ctx->ctx_lock);
1585 /*
1586 * We could have raced with io_destroy() and are currently holding a
1587 * reference to ctx which should be destroyed. We cannot submit IO
1588 * since ctx gets freed as soon as io_submit() puts its reference. The
1589 * check here is reliable: io_destroy() sets ctx->dead before waiting
1590 * for outstanding IO and the barrier between these two is realized by
1591 * unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
1592 * increment ctx->reqs_active before checking for ctx->dead and the
1593 * barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
1594 * don't see ctx->dead set here, io_destroy() waits for our IO to
1595 * finish.
1596 */
1597 if (ctx->dead) {
1598 spin_unlock_irq(&ctx->ctx_lock);
1599 ret = -EINVAL;
1600 goto out_put_req;
1601 }
1602 aio_run_iocb(req);
1603 if (!list_empty(&ctx->run_list)) {
1604 /* drain the run list */
1605 while (__aio_run_iocbs(ctx))
1606 ;
1607 }
1608 spin_unlock_irq(&ctx->ctx_lock);
1609
1610 aio_put_req(req); /* drop extra ref to req */
1611 return 0;
1612
1613out_put_req:
1614 aio_put_req(req); /* drop extra ref to req */
1615 aio_put_req(req); /* drop i/o ref to req */
1616 return ret;
1617}
1618
1619long do_io_submit(aio_context_t ctx_id, long nr,
1620 struct iocb __user *__user *iocbpp, bool compat)
1621{
1622 struct kioctx *ctx;
1623 long ret = 0;
1624 int i;
1625 struct blk_plug plug;
1626
1627 if (unlikely(nr < 0))
1628 return -EINVAL;
1629
1630 if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
1631 nr = LONG_MAX/sizeof(*iocbpp);
1632
1633 if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
1634 return -EFAULT;
1635
1636 ctx = lookup_ioctx(ctx_id);
1637 if (unlikely(!ctx)) {
1638 pr_debug("EINVAL: io_submit: invalid context id\n");
1639 return -EINVAL;
1640 }
1641
1642 blk_start_plug(&plug);
1643
1644 /*
1645 * AKPM: should this return a partial result if some of the IOs were
1646 * successfully submitted?
1647 */
1648 for (i=0; i<nr; i++) {
1649 struct iocb __user *user_iocb;
1650 struct iocb tmp;
1651
1652 if (unlikely(__get_user(user_iocb, iocbpp + i))) {
1653 ret = -EFAULT;
1654 break;
1655 }
1656
1657 if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
1658 ret = -EFAULT;
1659 break;
1660 }
1661
1662 ret = io_submit_one(ctx, user_iocb, &tmp, compat);
1663 if (ret)
1664 break;
1665 }
1666 blk_finish_plug(&plug);
1667
1668 put_ioctx(ctx);
1669 return i ? i : ret;
1670}
1671
1672/* sys_io_submit:
1673 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1674 * the number of iocbs queued. May return -EINVAL if the aio_context
1675 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1676 * *iocbpp[0] is not properly initialized, if the operation specified
1677 * is invalid for the file descriptor in the iocb. May fail with
1678 * -EFAULT if any of the data structures point to invalid data. May
1679 * fail with -EBADF if the file descriptor specified in the first
1680 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1681 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1682 * fail with -ENOSYS if not implemented.
1683 */
1684SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1685 struct iocb __user * __user *, iocbpp)
1686{
1687 return do_io_submit(ctx_id, nr, iocbpp, 0);
1688}
1689
1690/* lookup_kiocb
1691 * Finds a given iocb for cancellation.
1692 */
1693static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
1694 u32 key)
1695{
1696 struct list_head *pos;
1697
1698 assert_spin_locked(&ctx->ctx_lock);
1699
1700 /* TODO: use a hash or array, this sucks. */
1701 list_for_each(pos, &ctx->active_reqs) {
1702 struct kiocb *kiocb = list_kiocb(pos);
1703 if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
1704 return kiocb;
1705 }
1706 return NULL;
1707}
1708
1709/* sys_io_cancel:
1710 * Attempts to cancel an iocb previously passed to io_submit. If
1711 * the operation is successfully cancelled, the resulting event is
1712 * copied into the memory pointed to by result without being placed
1713 * into the completion queue and 0 is returned. May fail with
1714 * -EFAULT if any of the data structures pointed to are invalid.
1715 * May fail with -EINVAL if aio_context specified by ctx_id is
1716 * invalid. May fail with -EAGAIN if the iocb specified was not
1717 * cancelled. Will fail with -ENOSYS if not implemented.
1718 */
1719SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1720 struct io_event __user *, result)
1721{
1722 int (*cancel)(struct kiocb *iocb, struct io_event *res);
1723 struct kioctx *ctx;
1724 struct kiocb *kiocb;
1725 u32 key;
1726 int ret;
1727
1728 ret = get_user(key, &iocb->aio_key);
1729 if (unlikely(ret))
1730 return -EFAULT;
1731
1732 ctx = lookup_ioctx(ctx_id);
1733 if (unlikely(!ctx))
1734 return -EINVAL;
1735
1736 spin_lock_irq(&ctx->ctx_lock);
1737 ret = -EAGAIN;
1738 kiocb = lookup_kiocb(ctx, iocb, key);
1739 if (kiocb && kiocb->ki_cancel) {
1740 cancel = kiocb->ki_cancel;
1741 kiocb->ki_users ++;
1742 kiocbSetCancelled(kiocb);
1743 } else
1744 cancel = NULL;
1745 spin_unlock_irq(&ctx->ctx_lock);
1746
1747 if (NULL != cancel) {
1748 struct io_event tmp;
1749 pr_debug("calling cancel\n");
1750 memset(&tmp, 0, sizeof(tmp));
1751 tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
1752 tmp.data = kiocb->ki_user_data;
1753 ret = cancel(kiocb, &tmp);
1754 if (!ret) {
1755 /* Cancellation succeeded -- copy the result
1756 * into the user's buffer.
1757 */
1758 if (copy_to_user(result, &tmp, sizeof(tmp)))
1759 ret = -EFAULT;
1760 }
1761 } else
1762 ret = -EINVAL;
1763
1764 put_ioctx(ctx);
1765
1766 return ret;
1767}
1768
1769/* io_getevents:
1770 * Attempts to read at least min_nr events and up to nr events from
1771 * the completion queue for the aio_context specified by ctx_id. If
1772 * it succeeds, the number of read events is returned. May fail with
1773 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
1774 * out of range, if timeout is out of range. May fail with -EFAULT
1775 * if any of the memory specified is invalid. May return 0 or
1776 * < min_nr if the timeout specified by timeout has elapsed
1777 * before sufficient events are available, where timeout == NULL
1778 * specifies an infinite timeout. Note that the timeout pointed to by
1779 * timeout is relative and will be updated if not NULL and the
1780 * operation blocks. Will fail with -ENOSYS if not implemented.
1781 */
1782SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
1783 long, min_nr,
1784 long, nr,
1785 struct io_event __user *, events,
1786 struct timespec __user *, timeout)
1787{
1788 struct kioctx *ioctx = lookup_ioctx(ctx_id);
1789 long ret = -EINVAL;
1790
1791 if (likely(ioctx)) {
1792 if (likely(min_nr <= nr && min_nr >= 0))
1793 ret = read_events(ioctx, min_nr, nr, events, timeout);
1794 put_ioctx(ioctx);
1795 }
1796
1797 asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
1798 return ret;
1799}
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 * Copyright 2018 Christoph Hellwig.
9 *
10 * See ../COPYING for licensing terms.
11 */
12#define pr_fmt(fmt) "%s: " fmt, __func__
13
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/errno.h>
17#include <linux/time.h>
18#include <linux/aio_abi.h>
19#include <linux/export.h>
20#include <linux/syscalls.h>
21#include <linux/backing-dev.h>
22#include <linux/refcount.h>
23#include <linux/uio.h>
24
25#include <linux/sched/signal.h>
26#include <linux/fs.h>
27#include <linux/file.h>
28#include <linux/mm.h>
29#include <linux/mman.h>
30#include <linux/percpu.h>
31#include <linux/slab.h>
32#include <linux/timer.h>
33#include <linux/aio.h>
34#include <linux/highmem.h>
35#include <linux/workqueue.h>
36#include <linux/security.h>
37#include <linux/eventfd.h>
38#include <linux/blkdev.h>
39#include <linux/compat.h>
40#include <linux/migrate.h>
41#include <linux/ramfs.h>
42#include <linux/percpu-refcount.h>
43#include <linux/mount.h>
44#include <linux/pseudo_fs.h>
45
46#include <linux/uaccess.h>
47#include <linux/nospec.h>
48
49#include "internal.h"
50
51#define KIOCB_KEY 0
52
53#define AIO_RING_MAGIC 0xa10a10a1
54#define AIO_RING_COMPAT_FEATURES 1
55#define AIO_RING_INCOMPAT_FEATURES 0
56struct aio_ring {
57 unsigned id; /* kernel internal index number */
58 unsigned nr; /* number of io_events */
59 unsigned head; /* Written to by userland or under ring_lock
60 * mutex by aio_read_events_ring(). */
61 unsigned tail;
62
63 unsigned magic;
64 unsigned compat_features;
65 unsigned incompat_features;
66 unsigned header_length; /* size of aio_ring */
67
68
69 struct io_event io_events[];
70}; /* 128 bytes + ring size */
71
72/*
73 * Plugging is meant to work with larger batches of IOs. If we don't
74 * have more than the below, then don't bother setting up a plug.
75 */
76#define AIO_PLUG_THRESHOLD 2
77
78#define AIO_RING_PAGES 8
79
80struct kioctx_table {
81 struct rcu_head rcu;
82 unsigned nr;
83 struct kioctx __rcu *table[];
84};
85
86struct kioctx_cpu {
87 unsigned reqs_available;
88};
89
90struct ctx_rq_wait {
91 struct completion comp;
92 atomic_t count;
93};
94
95struct kioctx {
96 struct percpu_ref users;
97 atomic_t dead;
98
99 struct percpu_ref reqs;
100
101 unsigned long user_id;
102
103 struct __percpu kioctx_cpu *cpu;
104
105 /*
106 * For percpu reqs_available, number of slots we move to/from global
107 * counter at a time:
108 */
109 unsigned req_batch;
110 /*
111 * This is what userspace passed to io_setup(), it's not used for
112 * anything but counting against the global max_reqs quota.
113 *
114 * The real limit is nr_events - 1, which will be larger (see
115 * aio_setup_ring())
116 */
117 unsigned max_reqs;
118
119 /* Size of ringbuffer, in units of struct io_event */
120 unsigned nr_events;
121
122 unsigned long mmap_base;
123 unsigned long mmap_size;
124
125 struct page **ring_pages;
126 long nr_pages;
127
128 struct rcu_work free_rwork; /* see free_ioctx() */
129
130 /*
131 * signals when all in-flight requests are done
132 */
133 struct ctx_rq_wait *rq_wait;
134
135 struct {
136 /*
137 * This counts the number of available slots in the ringbuffer,
138 * so we avoid overflowing it: it's decremented (if positive)
139 * when allocating a kiocb and incremented when the resulting
140 * io_event is pulled off the ringbuffer.
141 *
142 * We batch accesses to it with a percpu version.
143 */
144 atomic_t reqs_available;
145 } ____cacheline_aligned_in_smp;
146
147 struct {
148 spinlock_t ctx_lock;
149 struct list_head active_reqs; /* used for cancellation */
150 } ____cacheline_aligned_in_smp;
151
152 struct {
153 struct mutex ring_lock;
154 wait_queue_head_t wait;
155 } ____cacheline_aligned_in_smp;
156
157 struct {
158 unsigned tail;
159 unsigned completed_events;
160 spinlock_t completion_lock;
161 } ____cacheline_aligned_in_smp;
162
163 struct page *internal_pages[AIO_RING_PAGES];
164 struct file *aio_ring_file;
165
166 unsigned id;
167};
168
169/*
170 * First field must be the file pointer in all the
171 * iocb unions! See also 'struct kiocb' in <linux/fs.h>
172 */
173struct fsync_iocb {
174 struct file *file;
175 struct work_struct work;
176 bool datasync;
177 struct cred *creds;
178};
179
180struct poll_iocb {
181 struct file *file;
182 struct wait_queue_head *head;
183 __poll_t events;
184 bool cancelled;
185 bool work_scheduled;
186 bool work_need_resched;
187 struct wait_queue_entry wait;
188 struct work_struct work;
189};
190
191/*
192 * NOTE! Each of the iocb union members has the file pointer
193 * as the first entry in their struct definition. So you can
194 * access the file pointer through any of the sub-structs,
195 * or directly as just 'ki_filp' in this struct.
196 */
197struct aio_kiocb {
198 union {
199 struct file *ki_filp;
200 struct kiocb rw;
201 struct fsync_iocb fsync;
202 struct poll_iocb poll;
203 };
204
205 struct kioctx *ki_ctx;
206 kiocb_cancel_fn *ki_cancel;
207
208 struct io_event ki_res;
209
210 struct list_head ki_list; /* the aio core uses this
211 * for cancellation */
212 refcount_t ki_refcnt;
213
214 /*
215 * If the aio_resfd field of the userspace iocb is not zero,
216 * this is the underlying eventfd context to deliver events to.
217 */
218 struct eventfd_ctx *ki_eventfd;
219};
220
221/*------ sysctl variables----*/
222static DEFINE_SPINLOCK(aio_nr_lock);
223static unsigned long aio_nr; /* current system wide number of aio requests */
224static unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
225/*----end sysctl variables---*/
226#ifdef CONFIG_SYSCTL
227static struct ctl_table aio_sysctls[] = {
228 {
229 .procname = "aio-nr",
230 .data = &aio_nr,
231 .maxlen = sizeof(aio_nr),
232 .mode = 0444,
233 .proc_handler = proc_doulongvec_minmax,
234 },
235 {
236 .procname = "aio-max-nr",
237 .data = &aio_max_nr,
238 .maxlen = sizeof(aio_max_nr),
239 .mode = 0644,
240 .proc_handler = proc_doulongvec_minmax,
241 },
242 {}
243};
244
245static void __init aio_sysctl_init(void)
246{
247 register_sysctl_init("fs", aio_sysctls);
248}
249#else
250#define aio_sysctl_init() do { } while (0)
251#endif
252
253static struct kmem_cache *kiocb_cachep;
254static struct kmem_cache *kioctx_cachep;
255
256static struct vfsmount *aio_mnt;
257
258static const struct file_operations aio_ring_fops;
259static const struct address_space_operations aio_ctx_aops;
260
261static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
262{
263 struct file *file;
264 struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
265 if (IS_ERR(inode))
266 return ERR_CAST(inode);
267
268 inode->i_mapping->a_ops = &aio_ctx_aops;
269 inode->i_mapping->private_data = ctx;
270 inode->i_size = PAGE_SIZE * nr_pages;
271
272 file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
273 O_RDWR, &aio_ring_fops);
274 if (IS_ERR(file))
275 iput(inode);
276 return file;
277}
278
279static int aio_init_fs_context(struct fs_context *fc)
280{
281 if (!init_pseudo(fc, AIO_RING_MAGIC))
282 return -ENOMEM;
283 fc->s_iflags |= SB_I_NOEXEC;
284 return 0;
285}
286
287/* aio_setup
288 * Creates the slab caches used by the aio routines, panic on
289 * failure as this is done early during the boot sequence.
290 */
291static int __init aio_setup(void)
292{
293 static struct file_system_type aio_fs = {
294 .name = "aio",
295 .init_fs_context = aio_init_fs_context,
296 .kill_sb = kill_anon_super,
297 };
298 aio_mnt = kern_mount(&aio_fs);
299 if (IS_ERR(aio_mnt))
300 panic("Failed to create aio fs mount.");
301
302 kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
303 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
304 aio_sysctl_init();
305 return 0;
306}
307__initcall(aio_setup);
308
309static void put_aio_ring_file(struct kioctx *ctx)
310{
311 struct file *aio_ring_file = ctx->aio_ring_file;
312 struct address_space *i_mapping;
313
314 if (aio_ring_file) {
315 truncate_setsize(file_inode(aio_ring_file), 0);
316
317 /* Prevent further access to the kioctx from migratepages */
318 i_mapping = aio_ring_file->f_mapping;
319 spin_lock(&i_mapping->private_lock);
320 i_mapping->private_data = NULL;
321 ctx->aio_ring_file = NULL;
322 spin_unlock(&i_mapping->private_lock);
323
324 fput(aio_ring_file);
325 }
326}
327
328static void aio_free_ring(struct kioctx *ctx)
329{
330 int i;
331
332 /* Disconnect the kiotx from the ring file. This prevents future
333 * accesses to the kioctx from page migration.
334 */
335 put_aio_ring_file(ctx);
336
337 for (i = 0; i < ctx->nr_pages; i++) {
338 struct page *page;
339 pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
340 page_count(ctx->ring_pages[i]));
341 page = ctx->ring_pages[i];
342 if (!page)
343 continue;
344 ctx->ring_pages[i] = NULL;
345 put_page(page);
346 }
347
348 if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
349 kfree(ctx->ring_pages);
350 ctx->ring_pages = NULL;
351 }
352}
353
354static int aio_ring_mremap(struct vm_area_struct *vma)
355{
356 struct file *file = vma->vm_file;
357 struct mm_struct *mm = vma->vm_mm;
358 struct kioctx_table *table;
359 int i, res = -EINVAL;
360
361 spin_lock(&mm->ioctx_lock);
362 rcu_read_lock();
363 table = rcu_dereference(mm->ioctx_table);
364 if (!table)
365 goto out_unlock;
366
367 for (i = 0; i < table->nr; i++) {
368 struct kioctx *ctx;
369
370 ctx = rcu_dereference(table->table[i]);
371 if (ctx && ctx->aio_ring_file == file) {
372 if (!atomic_read(&ctx->dead)) {
373 ctx->user_id = ctx->mmap_base = vma->vm_start;
374 res = 0;
375 }
376 break;
377 }
378 }
379
380out_unlock:
381 rcu_read_unlock();
382 spin_unlock(&mm->ioctx_lock);
383 return res;
384}
385
386static const struct vm_operations_struct aio_ring_vm_ops = {
387 .mremap = aio_ring_mremap,
388#if IS_ENABLED(CONFIG_MMU)
389 .fault = filemap_fault,
390 .map_pages = filemap_map_pages,
391 .page_mkwrite = filemap_page_mkwrite,
392#endif
393};
394
395static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
396{
397 vma->vm_flags |= VM_DONTEXPAND;
398 vma->vm_ops = &aio_ring_vm_ops;
399 return 0;
400}
401
402static const struct file_operations aio_ring_fops = {
403 .mmap = aio_ring_mmap,
404};
405
406#if IS_ENABLED(CONFIG_MIGRATION)
407static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
408 struct folio *src, enum migrate_mode mode)
409{
410 struct kioctx *ctx;
411 unsigned long flags;
412 pgoff_t idx;
413 int rc;
414
415 /*
416 * We cannot support the _NO_COPY case here, because copy needs to
417 * happen under the ctx->completion_lock. That does not work with the
418 * migration workflow of MIGRATE_SYNC_NO_COPY.
419 */
420 if (mode == MIGRATE_SYNC_NO_COPY)
421 return -EINVAL;
422
423 rc = 0;
424
425 /* mapping->private_lock here protects against the kioctx teardown. */
426 spin_lock(&mapping->private_lock);
427 ctx = mapping->private_data;
428 if (!ctx) {
429 rc = -EINVAL;
430 goto out;
431 }
432
433 /* The ring_lock mutex. The prevents aio_read_events() from writing
434 * to the ring's head, and prevents page migration from mucking in
435 * a partially initialized kiotx.
436 */
437 if (!mutex_trylock(&ctx->ring_lock)) {
438 rc = -EAGAIN;
439 goto out;
440 }
441
442 idx = src->index;
443 if (idx < (pgoff_t)ctx->nr_pages) {
444 /* Make sure the old folio hasn't already been changed */
445 if (ctx->ring_pages[idx] != &src->page)
446 rc = -EAGAIN;
447 } else
448 rc = -EINVAL;
449
450 if (rc != 0)
451 goto out_unlock;
452
453 /* Writeback must be complete */
454 BUG_ON(folio_test_writeback(src));
455 folio_get(dst);
456
457 rc = folio_migrate_mapping(mapping, dst, src, 1);
458 if (rc != MIGRATEPAGE_SUCCESS) {
459 folio_put(dst);
460 goto out_unlock;
461 }
462
463 /* Take completion_lock to prevent other writes to the ring buffer
464 * while the old folio is copied to the new. This prevents new
465 * events from being lost.
466 */
467 spin_lock_irqsave(&ctx->completion_lock, flags);
468 folio_migrate_copy(dst, src);
469 BUG_ON(ctx->ring_pages[idx] != &src->page);
470 ctx->ring_pages[idx] = &dst->page;
471 spin_unlock_irqrestore(&ctx->completion_lock, flags);
472
473 /* The old folio is no longer accessible. */
474 folio_put(src);
475
476out_unlock:
477 mutex_unlock(&ctx->ring_lock);
478out:
479 spin_unlock(&mapping->private_lock);
480 return rc;
481}
482#else
483#define aio_migrate_folio NULL
484#endif
485
486static const struct address_space_operations aio_ctx_aops = {
487 .dirty_folio = noop_dirty_folio,
488 .migrate_folio = aio_migrate_folio,
489};
490
491static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
492{
493 struct aio_ring *ring;
494 struct mm_struct *mm = current->mm;
495 unsigned long size, unused;
496 int nr_pages;
497 int i;
498 struct file *file;
499
500 /* Compensate for the ring buffer's head/tail overlap entry */
501 nr_events += 2; /* 1 is required, 2 for good luck */
502
503 size = sizeof(struct aio_ring);
504 size += sizeof(struct io_event) * nr_events;
505
506 nr_pages = PFN_UP(size);
507 if (nr_pages < 0)
508 return -EINVAL;
509
510 file = aio_private_file(ctx, nr_pages);
511 if (IS_ERR(file)) {
512 ctx->aio_ring_file = NULL;
513 return -ENOMEM;
514 }
515
516 ctx->aio_ring_file = file;
517 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
518 / sizeof(struct io_event);
519
520 ctx->ring_pages = ctx->internal_pages;
521 if (nr_pages > AIO_RING_PAGES) {
522 ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
523 GFP_KERNEL);
524 if (!ctx->ring_pages) {
525 put_aio_ring_file(ctx);
526 return -ENOMEM;
527 }
528 }
529
530 for (i = 0; i < nr_pages; i++) {
531 struct page *page;
532 page = find_or_create_page(file->f_mapping,
533 i, GFP_HIGHUSER | __GFP_ZERO);
534 if (!page)
535 break;
536 pr_debug("pid(%d) page[%d]->count=%d\n",
537 current->pid, i, page_count(page));
538 SetPageUptodate(page);
539 unlock_page(page);
540
541 ctx->ring_pages[i] = page;
542 }
543 ctx->nr_pages = i;
544
545 if (unlikely(i != nr_pages)) {
546 aio_free_ring(ctx);
547 return -ENOMEM;
548 }
549
550 ctx->mmap_size = nr_pages * PAGE_SIZE;
551 pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
552
553 if (mmap_write_lock_killable(mm)) {
554 ctx->mmap_size = 0;
555 aio_free_ring(ctx);
556 return -EINTR;
557 }
558
559 ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
560 PROT_READ | PROT_WRITE,
561 MAP_SHARED, 0, &unused, NULL);
562 mmap_write_unlock(mm);
563 if (IS_ERR((void *)ctx->mmap_base)) {
564 ctx->mmap_size = 0;
565 aio_free_ring(ctx);
566 return -ENOMEM;
567 }
568
569 pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
570
571 ctx->user_id = ctx->mmap_base;
572 ctx->nr_events = nr_events; /* trusted copy */
573
574 ring = kmap_atomic(ctx->ring_pages[0]);
575 ring->nr = nr_events; /* user copy */
576 ring->id = ~0U;
577 ring->head = ring->tail = 0;
578 ring->magic = AIO_RING_MAGIC;
579 ring->compat_features = AIO_RING_COMPAT_FEATURES;
580 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
581 ring->header_length = sizeof(struct aio_ring);
582 kunmap_atomic(ring);
583 flush_dcache_page(ctx->ring_pages[0]);
584
585 return 0;
586}
587
588#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
589#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
590#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
591
592void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
593{
594 struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
595 struct kioctx *ctx = req->ki_ctx;
596 unsigned long flags;
597
598 if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
599 return;
600
601 spin_lock_irqsave(&ctx->ctx_lock, flags);
602 list_add_tail(&req->ki_list, &ctx->active_reqs);
603 req->ki_cancel = cancel;
604 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
605}
606EXPORT_SYMBOL(kiocb_set_cancel_fn);
607
608/*
609 * free_ioctx() should be RCU delayed to synchronize against the RCU
610 * protected lookup_ioctx() and also needs process context to call
611 * aio_free_ring(). Use rcu_work.
612 */
613static void free_ioctx(struct work_struct *work)
614{
615 struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
616 free_rwork);
617 pr_debug("freeing %p\n", ctx);
618
619 aio_free_ring(ctx);
620 free_percpu(ctx->cpu);
621 percpu_ref_exit(&ctx->reqs);
622 percpu_ref_exit(&ctx->users);
623 kmem_cache_free(kioctx_cachep, ctx);
624}
625
626static void free_ioctx_reqs(struct percpu_ref *ref)
627{
628 struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
629
630 /* At this point we know that there are no any in-flight requests */
631 if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
632 complete(&ctx->rq_wait->comp);
633
634 /* Synchronize against RCU protected table->table[] dereferences */
635 INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
636 queue_rcu_work(system_wq, &ctx->free_rwork);
637}
638
639/*
640 * When this function runs, the kioctx has been removed from the "hash table"
641 * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
642 * now it's safe to cancel any that need to be.
643 */
644static void free_ioctx_users(struct percpu_ref *ref)
645{
646 struct kioctx *ctx = container_of(ref, struct kioctx, users);
647 struct aio_kiocb *req;
648
649 spin_lock_irq(&ctx->ctx_lock);
650
651 while (!list_empty(&ctx->active_reqs)) {
652 req = list_first_entry(&ctx->active_reqs,
653 struct aio_kiocb, ki_list);
654 req->ki_cancel(&req->rw);
655 list_del_init(&req->ki_list);
656 }
657
658 spin_unlock_irq(&ctx->ctx_lock);
659
660 percpu_ref_kill(&ctx->reqs);
661 percpu_ref_put(&ctx->reqs);
662}
663
664static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
665{
666 unsigned i, new_nr;
667 struct kioctx_table *table, *old;
668 struct aio_ring *ring;
669
670 spin_lock(&mm->ioctx_lock);
671 table = rcu_dereference_raw(mm->ioctx_table);
672
673 while (1) {
674 if (table)
675 for (i = 0; i < table->nr; i++)
676 if (!rcu_access_pointer(table->table[i])) {
677 ctx->id = i;
678 rcu_assign_pointer(table->table[i], ctx);
679 spin_unlock(&mm->ioctx_lock);
680
681 /* While kioctx setup is in progress,
682 * we are protected from page migration
683 * changes ring_pages by ->ring_lock.
684 */
685 ring = kmap_atomic(ctx->ring_pages[0]);
686 ring->id = ctx->id;
687 kunmap_atomic(ring);
688 return 0;
689 }
690
691 new_nr = (table ? table->nr : 1) * 4;
692 spin_unlock(&mm->ioctx_lock);
693
694 table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL);
695 if (!table)
696 return -ENOMEM;
697
698 table->nr = new_nr;
699
700 spin_lock(&mm->ioctx_lock);
701 old = rcu_dereference_raw(mm->ioctx_table);
702
703 if (!old) {
704 rcu_assign_pointer(mm->ioctx_table, table);
705 } else if (table->nr > old->nr) {
706 memcpy(table->table, old->table,
707 old->nr * sizeof(struct kioctx *));
708
709 rcu_assign_pointer(mm->ioctx_table, table);
710 kfree_rcu(old, rcu);
711 } else {
712 kfree(table);
713 table = old;
714 }
715 }
716}
717
718static void aio_nr_sub(unsigned nr)
719{
720 spin_lock(&aio_nr_lock);
721 if (WARN_ON(aio_nr - nr > aio_nr))
722 aio_nr = 0;
723 else
724 aio_nr -= nr;
725 spin_unlock(&aio_nr_lock);
726}
727
728/* ioctx_alloc
729 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
730 */
731static struct kioctx *ioctx_alloc(unsigned nr_events)
732{
733 struct mm_struct *mm = current->mm;
734 struct kioctx *ctx;
735 int err = -ENOMEM;
736
737 /*
738 * Store the original nr_events -- what userspace passed to io_setup(),
739 * for counting against the global limit -- before it changes.
740 */
741 unsigned int max_reqs = nr_events;
742
743 /*
744 * We keep track of the number of available ringbuffer slots, to prevent
745 * overflow (reqs_available), and we also use percpu counters for this.
746 *
747 * So since up to half the slots might be on other cpu's percpu counters
748 * and unavailable, double nr_events so userspace sees what they
749 * expected: additionally, we move req_batch slots to/from percpu
750 * counters at a time, so make sure that isn't 0:
751 */
752 nr_events = max(nr_events, num_possible_cpus() * 4);
753 nr_events *= 2;
754
755 /* Prevent overflows */
756 if (nr_events > (0x10000000U / sizeof(struct io_event))) {
757 pr_debug("ENOMEM: nr_events too high\n");
758 return ERR_PTR(-EINVAL);
759 }
760
761 if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
762 return ERR_PTR(-EAGAIN);
763
764 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
765 if (!ctx)
766 return ERR_PTR(-ENOMEM);
767
768 ctx->max_reqs = max_reqs;
769
770 spin_lock_init(&ctx->ctx_lock);
771 spin_lock_init(&ctx->completion_lock);
772 mutex_init(&ctx->ring_lock);
773 /* Protect against page migration throughout kiotx setup by keeping
774 * the ring_lock mutex held until setup is complete. */
775 mutex_lock(&ctx->ring_lock);
776 init_waitqueue_head(&ctx->wait);
777
778 INIT_LIST_HEAD(&ctx->active_reqs);
779
780 if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
781 goto err;
782
783 if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
784 goto err;
785
786 ctx->cpu = alloc_percpu(struct kioctx_cpu);
787 if (!ctx->cpu)
788 goto err;
789
790 err = aio_setup_ring(ctx, nr_events);
791 if (err < 0)
792 goto err;
793
794 atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
795 ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
796 if (ctx->req_batch < 1)
797 ctx->req_batch = 1;
798
799 /* limit the number of system wide aios */
800 spin_lock(&aio_nr_lock);
801 if (aio_nr + ctx->max_reqs > aio_max_nr ||
802 aio_nr + ctx->max_reqs < aio_nr) {
803 spin_unlock(&aio_nr_lock);
804 err = -EAGAIN;
805 goto err_ctx;
806 }
807 aio_nr += ctx->max_reqs;
808 spin_unlock(&aio_nr_lock);
809
810 percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
811 percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
812
813 err = ioctx_add_table(ctx, mm);
814 if (err)
815 goto err_cleanup;
816
817 /* Release the ring_lock mutex now that all setup is complete. */
818 mutex_unlock(&ctx->ring_lock);
819
820 pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
821 ctx, ctx->user_id, mm, ctx->nr_events);
822 return ctx;
823
824err_cleanup:
825 aio_nr_sub(ctx->max_reqs);
826err_ctx:
827 atomic_set(&ctx->dead, 1);
828 if (ctx->mmap_size)
829 vm_munmap(ctx->mmap_base, ctx->mmap_size);
830 aio_free_ring(ctx);
831err:
832 mutex_unlock(&ctx->ring_lock);
833 free_percpu(ctx->cpu);
834 percpu_ref_exit(&ctx->reqs);
835 percpu_ref_exit(&ctx->users);
836 kmem_cache_free(kioctx_cachep, ctx);
837 pr_debug("error allocating ioctx %d\n", err);
838 return ERR_PTR(err);
839}
840
841/* kill_ioctx
842 * Cancels all outstanding aio requests on an aio context. Used
843 * when the processes owning a context have all exited to encourage
844 * the rapid destruction of the kioctx.
845 */
846static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
847 struct ctx_rq_wait *wait)
848{
849 struct kioctx_table *table;
850
851 spin_lock(&mm->ioctx_lock);
852 if (atomic_xchg(&ctx->dead, 1)) {
853 spin_unlock(&mm->ioctx_lock);
854 return -EINVAL;
855 }
856
857 table = rcu_dereference_raw(mm->ioctx_table);
858 WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
859 RCU_INIT_POINTER(table->table[ctx->id], NULL);
860 spin_unlock(&mm->ioctx_lock);
861
862 /* free_ioctx_reqs() will do the necessary RCU synchronization */
863 wake_up_all(&ctx->wait);
864
865 /*
866 * It'd be more correct to do this in free_ioctx(), after all
867 * the outstanding kiocbs have finished - but by then io_destroy
868 * has already returned, so io_setup() could potentially return
869 * -EAGAIN with no ioctxs actually in use (as far as userspace
870 * could tell).
871 */
872 aio_nr_sub(ctx->max_reqs);
873
874 if (ctx->mmap_size)
875 vm_munmap(ctx->mmap_base, ctx->mmap_size);
876
877 ctx->rq_wait = wait;
878 percpu_ref_kill(&ctx->users);
879 return 0;
880}
881
882/*
883 * exit_aio: called when the last user of mm goes away. At this point, there is
884 * no way for any new requests to be submited or any of the io_* syscalls to be
885 * called on the context.
886 *
887 * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
888 * them.
889 */
890void exit_aio(struct mm_struct *mm)
891{
892 struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
893 struct ctx_rq_wait wait;
894 int i, skipped;
895
896 if (!table)
897 return;
898
899 atomic_set(&wait.count, table->nr);
900 init_completion(&wait.comp);
901
902 skipped = 0;
903 for (i = 0; i < table->nr; ++i) {
904 struct kioctx *ctx =
905 rcu_dereference_protected(table->table[i], true);
906
907 if (!ctx) {
908 skipped++;
909 continue;
910 }
911
912 /*
913 * We don't need to bother with munmap() here - exit_mmap(mm)
914 * is coming and it'll unmap everything. And we simply can't,
915 * this is not necessarily our ->mm.
916 * Since kill_ioctx() uses non-zero ->mmap_size as indicator
917 * that it needs to unmap the area, just set it to 0.
918 */
919 ctx->mmap_size = 0;
920 kill_ioctx(mm, ctx, &wait);
921 }
922
923 if (!atomic_sub_and_test(skipped, &wait.count)) {
924 /* Wait until all IO for the context are done. */
925 wait_for_completion(&wait.comp);
926 }
927
928 RCU_INIT_POINTER(mm->ioctx_table, NULL);
929 kfree(table);
930}
931
932static void put_reqs_available(struct kioctx *ctx, unsigned nr)
933{
934 struct kioctx_cpu *kcpu;
935 unsigned long flags;
936
937 local_irq_save(flags);
938 kcpu = this_cpu_ptr(ctx->cpu);
939 kcpu->reqs_available += nr;
940
941 while (kcpu->reqs_available >= ctx->req_batch * 2) {
942 kcpu->reqs_available -= ctx->req_batch;
943 atomic_add(ctx->req_batch, &ctx->reqs_available);
944 }
945
946 local_irq_restore(flags);
947}
948
949static bool __get_reqs_available(struct kioctx *ctx)
950{
951 struct kioctx_cpu *kcpu;
952 bool ret = false;
953 unsigned long flags;
954
955 local_irq_save(flags);
956 kcpu = this_cpu_ptr(ctx->cpu);
957 if (!kcpu->reqs_available) {
958 int avail = atomic_read(&ctx->reqs_available);
959
960 do {
961 if (avail < ctx->req_batch)
962 goto out;
963 } while (!atomic_try_cmpxchg(&ctx->reqs_available,
964 &avail, avail - ctx->req_batch));
965
966 kcpu->reqs_available += ctx->req_batch;
967 }
968
969 ret = true;
970 kcpu->reqs_available--;
971out:
972 local_irq_restore(flags);
973 return ret;
974}
975
976/* refill_reqs_available
977 * Updates the reqs_available reference counts used for tracking the
978 * number of free slots in the completion ring. This can be called
979 * from aio_complete() (to optimistically update reqs_available) or
980 * from aio_get_req() (the we're out of events case). It must be
981 * called holding ctx->completion_lock.
982 */
983static void refill_reqs_available(struct kioctx *ctx, unsigned head,
984 unsigned tail)
985{
986 unsigned events_in_ring, completed;
987
988 /* Clamp head since userland can write to it. */
989 head %= ctx->nr_events;
990 if (head <= tail)
991 events_in_ring = tail - head;
992 else
993 events_in_ring = ctx->nr_events - (head - tail);
994
995 completed = ctx->completed_events;
996 if (events_in_ring < completed)
997 completed -= events_in_ring;
998 else
999 completed = 0;
1000
1001 if (!completed)
1002 return;
1003
1004 ctx->completed_events -= completed;
1005 put_reqs_available(ctx, completed);
1006}
1007
1008/* user_refill_reqs_available
1009 * Called to refill reqs_available when aio_get_req() encounters an
1010 * out of space in the completion ring.
1011 */
1012static void user_refill_reqs_available(struct kioctx *ctx)
1013{
1014 spin_lock_irq(&ctx->completion_lock);
1015 if (ctx->completed_events) {
1016 struct aio_ring *ring;
1017 unsigned head;
1018
1019 /* Access of ring->head may race with aio_read_events_ring()
1020 * here, but that's okay since whether we read the old version
1021 * or the new version, and either will be valid. The important
1022 * part is that head cannot pass tail since we prevent
1023 * aio_complete() from updating tail by holding
1024 * ctx->completion_lock. Even if head is invalid, the check
1025 * against ctx->completed_events below will make sure we do the
1026 * safe/right thing.
1027 */
1028 ring = kmap_atomic(ctx->ring_pages[0]);
1029 head = ring->head;
1030 kunmap_atomic(ring);
1031
1032 refill_reqs_available(ctx, head, ctx->tail);
1033 }
1034
1035 spin_unlock_irq(&ctx->completion_lock);
1036}
1037
1038static bool get_reqs_available(struct kioctx *ctx)
1039{
1040 if (__get_reqs_available(ctx))
1041 return true;
1042 user_refill_reqs_available(ctx);
1043 return __get_reqs_available(ctx);
1044}
1045
1046/* aio_get_req
1047 * Allocate a slot for an aio request.
1048 * Returns NULL if no requests are free.
1049 *
1050 * The refcount is initialized to 2 - one for the async op completion,
1051 * one for the synchronous code that does this.
1052 */
1053static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
1054{
1055 struct aio_kiocb *req;
1056
1057 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
1058 if (unlikely(!req))
1059 return NULL;
1060
1061 if (unlikely(!get_reqs_available(ctx))) {
1062 kmem_cache_free(kiocb_cachep, req);
1063 return NULL;
1064 }
1065
1066 percpu_ref_get(&ctx->reqs);
1067 req->ki_ctx = ctx;
1068 INIT_LIST_HEAD(&req->ki_list);
1069 refcount_set(&req->ki_refcnt, 2);
1070 req->ki_eventfd = NULL;
1071 return req;
1072}
1073
1074static struct kioctx *lookup_ioctx(unsigned long ctx_id)
1075{
1076 struct aio_ring __user *ring = (void __user *)ctx_id;
1077 struct mm_struct *mm = current->mm;
1078 struct kioctx *ctx, *ret = NULL;
1079 struct kioctx_table *table;
1080 unsigned id;
1081
1082 if (get_user(id, &ring->id))
1083 return NULL;
1084
1085 rcu_read_lock();
1086 table = rcu_dereference(mm->ioctx_table);
1087
1088 if (!table || id >= table->nr)
1089 goto out;
1090
1091 id = array_index_nospec(id, table->nr);
1092 ctx = rcu_dereference(table->table[id]);
1093 if (ctx && ctx->user_id == ctx_id) {
1094 if (percpu_ref_tryget_live(&ctx->users))
1095 ret = ctx;
1096 }
1097out:
1098 rcu_read_unlock();
1099 return ret;
1100}
1101
1102static inline void iocb_destroy(struct aio_kiocb *iocb)
1103{
1104 if (iocb->ki_eventfd)
1105 eventfd_ctx_put(iocb->ki_eventfd);
1106 if (iocb->ki_filp)
1107 fput(iocb->ki_filp);
1108 percpu_ref_put(&iocb->ki_ctx->reqs);
1109 kmem_cache_free(kiocb_cachep, iocb);
1110}
1111
1112/* aio_complete
1113 * Called when the io request on the given iocb is complete.
1114 */
1115static void aio_complete(struct aio_kiocb *iocb)
1116{
1117 struct kioctx *ctx = iocb->ki_ctx;
1118 struct aio_ring *ring;
1119 struct io_event *ev_page, *event;
1120 unsigned tail, pos, head;
1121 unsigned long flags;
1122
1123 /*
1124 * Add a completion event to the ring buffer. Must be done holding
1125 * ctx->completion_lock to prevent other code from messing with the tail
1126 * pointer since we might be called from irq context.
1127 */
1128 spin_lock_irqsave(&ctx->completion_lock, flags);
1129
1130 tail = ctx->tail;
1131 pos = tail + AIO_EVENTS_OFFSET;
1132
1133 if (++tail >= ctx->nr_events)
1134 tail = 0;
1135
1136 ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1137 event = ev_page + pos % AIO_EVENTS_PER_PAGE;
1138
1139 *event = iocb->ki_res;
1140
1141 kunmap_atomic(ev_page);
1142 flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1143
1144 pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
1145 (void __user *)(unsigned long)iocb->ki_res.obj,
1146 iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
1147
1148 /* after flagging the request as done, we
1149 * must never even look at it again
1150 */
1151 smp_wmb(); /* make event visible before updating tail */
1152
1153 ctx->tail = tail;
1154
1155 ring = kmap_atomic(ctx->ring_pages[0]);
1156 head = ring->head;
1157 ring->tail = tail;
1158 kunmap_atomic(ring);
1159 flush_dcache_page(ctx->ring_pages[0]);
1160
1161 ctx->completed_events++;
1162 if (ctx->completed_events > 1)
1163 refill_reqs_available(ctx, head, tail);
1164 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1165
1166 pr_debug("added to ring %p at [%u]\n", iocb, tail);
1167
1168 /*
1169 * Check if the user asked us to deliver the result through an
1170 * eventfd. The eventfd_signal() function is safe to be called
1171 * from IRQ context.
1172 */
1173 if (iocb->ki_eventfd)
1174 eventfd_signal(iocb->ki_eventfd, 1);
1175
1176 /*
1177 * We have to order our ring_info tail store above and test
1178 * of the wait list below outside the wait lock. This is
1179 * like in wake_up_bit() where clearing a bit has to be
1180 * ordered with the unlocked test.
1181 */
1182 smp_mb();
1183
1184 if (waitqueue_active(&ctx->wait))
1185 wake_up(&ctx->wait);
1186}
1187
1188static inline void iocb_put(struct aio_kiocb *iocb)
1189{
1190 if (refcount_dec_and_test(&iocb->ki_refcnt)) {
1191 aio_complete(iocb);
1192 iocb_destroy(iocb);
1193 }
1194}
1195
1196/* aio_read_events_ring
1197 * Pull an event off of the ioctx's event ring. Returns the number of
1198 * events fetched
1199 */
1200static long aio_read_events_ring(struct kioctx *ctx,
1201 struct io_event __user *event, long nr)
1202{
1203 struct aio_ring *ring;
1204 unsigned head, tail, pos;
1205 long ret = 0;
1206 int copy_ret;
1207
1208 /*
1209 * The mutex can block and wake us up and that will cause
1210 * wait_event_interruptible_hrtimeout() to schedule without sleeping
1211 * and repeat. This should be rare enough that it doesn't cause
1212 * peformance issues. See the comment in read_events() for more detail.
1213 */
1214 sched_annotate_sleep();
1215 mutex_lock(&ctx->ring_lock);
1216
1217 /* Access to ->ring_pages here is protected by ctx->ring_lock. */
1218 ring = kmap_atomic(ctx->ring_pages[0]);
1219 head = ring->head;
1220 tail = ring->tail;
1221 kunmap_atomic(ring);
1222
1223 /*
1224 * Ensure that once we've read the current tail pointer, that
1225 * we also see the events that were stored up to the tail.
1226 */
1227 smp_rmb();
1228
1229 pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
1230
1231 if (head == tail)
1232 goto out;
1233
1234 head %= ctx->nr_events;
1235 tail %= ctx->nr_events;
1236
1237 while (ret < nr) {
1238 long avail;
1239 struct io_event *ev;
1240 struct page *page;
1241
1242 avail = (head <= tail ? tail : ctx->nr_events) - head;
1243 if (head == tail)
1244 break;
1245
1246 pos = head + AIO_EVENTS_OFFSET;
1247 page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
1248 pos %= AIO_EVENTS_PER_PAGE;
1249
1250 avail = min(avail, nr - ret);
1251 avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
1252
1253 ev = kmap(page);
1254 copy_ret = copy_to_user(event + ret, ev + pos,
1255 sizeof(*ev) * avail);
1256 kunmap(page);
1257
1258 if (unlikely(copy_ret)) {
1259 ret = -EFAULT;
1260 goto out;
1261 }
1262
1263 ret += avail;
1264 head += avail;
1265 head %= ctx->nr_events;
1266 }
1267
1268 ring = kmap_atomic(ctx->ring_pages[0]);
1269 ring->head = head;
1270 kunmap_atomic(ring);
1271 flush_dcache_page(ctx->ring_pages[0]);
1272
1273 pr_debug("%li h%u t%u\n", ret, head, tail);
1274out:
1275 mutex_unlock(&ctx->ring_lock);
1276
1277 return ret;
1278}
1279
1280static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
1281 struct io_event __user *event, long *i)
1282{
1283 long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
1284
1285 if (ret > 0)
1286 *i += ret;
1287
1288 if (unlikely(atomic_read(&ctx->dead)))
1289 ret = -EINVAL;
1290
1291 if (!*i)
1292 *i = ret;
1293
1294 return ret < 0 || *i >= min_nr;
1295}
1296
1297static long read_events(struct kioctx *ctx, long min_nr, long nr,
1298 struct io_event __user *event,
1299 ktime_t until)
1300{
1301 long ret = 0;
1302
1303 /*
1304 * Note that aio_read_events() is being called as the conditional - i.e.
1305 * we're calling it after prepare_to_wait() has set task state to
1306 * TASK_INTERRUPTIBLE.
1307 *
1308 * But aio_read_events() can block, and if it blocks it's going to flip
1309 * the task state back to TASK_RUNNING.
1310 *
1311 * This should be ok, provided it doesn't flip the state back to
1312 * TASK_RUNNING and return 0 too much - that causes us to spin. That
1313 * will only happen if the mutex_lock() call blocks, and we then find
1314 * the ringbuffer empty. So in practice we should be ok, but it's
1315 * something to be aware of when touching this code.
1316 */
1317 if (until == 0)
1318 aio_read_events(ctx, min_nr, nr, event, &ret);
1319 else
1320 wait_event_interruptible_hrtimeout(ctx->wait,
1321 aio_read_events(ctx, min_nr, nr, event, &ret),
1322 until);
1323 return ret;
1324}
1325
1326/* sys_io_setup:
1327 * Create an aio_context capable of receiving at least nr_events.
1328 * ctxp must not point to an aio_context that already exists, and
1329 * must be initialized to 0 prior to the call. On successful
1330 * creation of the aio_context, *ctxp is filled in with the resulting
1331 * handle. May fail with -EINVAL if *ctxp is not initialized,
1332 * if the specified nr_events exceeds internal limits. May fail
1333 * with -EAGAIN if the specified nr_events exceeds the user's limit
1334 * of available events. May fail with -ENOMEM if insufficient kernel
1335 * resources are available. May fail with -EFAULT if an invalid
1336 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1337 * implemented.
1338 */
1339SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1340{
1341 struct kioctx *ioctx = NULL;
1342 unsigned long ctx;
1343 long ret;
1344
1345 ret = get_user(ctx, ctxp);
1346 if (unlikely(ret))
1347 goto out;
1348
1349 ret = -EINVAL;
1350 if (unlikely(ctx || nr_events == 0)) {
1351 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1352 ctx, nr_events);
1353 goto out;
1354 }
1355
1356 ioctx = ioctx_alloc(nr_events);
1357 ret = PTR_ERR(ioctx);
1358 if (!IS_ERR(ioctx)) {
1359 ret = put_user(ioctx->user_id, ctxp);
1360 if (ret)
1361 kill_ioctx(current->mm, ioctx, NULL);
1362 percpu_ref_put(&ioctx->users);
1363 }
1364
1365out:
1366 return ret;
1367}
1368
1369#ifdef CONFIG_COMPAT
1370COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
1371{
1372 struct kioctx *ioctx = NULL;
1373 unsigned long ctx;
1374 long ret;
1375
1376 ret = get_user(ctx, ctx32p);
1377 if (unlikely(ret))
1378 goto out;
1379
1380 ret = -EINVAL;
1381 if (unlikely(ctx || nr_events == 0)) {
1382 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1383 ctx, nr_events);
1384 goto out;
1385 }
1386
1387 ioctx = ioctx_alloc(nr_events);
1388 ret = PTR_ERR(ioctx);
1389 if (!IS_ERR(ioctx)) {
1390 /* truncating is ok because it's a user address */
1391 ret = put_user((u32)ioctx->user_id, ctx32p);
1392 if (ret)
1393 kill_ioctx(current->mm, ioctx, NULL);
1394 percpu_ref_put(&ioctx->users);
1395 }
1396
1397out:
1398 return ret;
1399}
1400#endif
1401
1402/* sys_io_destroy:
1403 * Destroy the aio_context specified. May cancel any outstanding
1404 * AIOs and block on completion. Will fail with -ENOSYS if not
1405 * implemented. May fail with -EINVAL if the context pointed to
1406 * is invalid.
1407 */
1408SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1409{
1410 struct kioctx *ioctx = lookup_ioctx(ctx);
1411 if (likely(NULL != ioctx)) {
1412 struct ctx_rq_wait wait;
1413 int ret;
1414
1415 init_completion(&wait.comp);
1416 atomic_set(&wait.count, 1);
1417
1418 /* Pass requests_done to kill_ioctx() where it can be set
1419 * in a thread-safe way. If we try to set it here then we have
1420 * a race condition if two io_destroy() called simultaneously.
1421 */
1422 ret = kill_ioctx(current->mm, ioctx, &wait);
1423 percpu_ref_put(&ioctx->users);
1424
1425 /* Wait until all IO for the context are done. Otherwise kernel
1426 * keep using user-space buffers even if user thinks the context
1427 * is destroyed.
1428 */
1429 if (!ret)
1430 wait_for_completion(&wait.comp);
1431
1432 return ret;
1433 }
1434 pr_debug("EINVAL: invalid context id\n");
1435 return -EINVAL;
1436}
1437
1438static void aio_remove_iocb(struct aio_kiocb *iocb)
1439{
1440 struct kioctx *ctx = iocb->ki_ctx;
1441 unsigned long flags;
1442
1443 spin_lock_irqsave(&ctx->ctx_lock, flags);
1444 list_del(&iocb->ki_list);
1445 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1446}
1447
1448static void aio_complete_rw(struct kiocb *kiocb, long res)
1449{
1450 struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
1451
1452 if (!list_empty_careful(&iocb->ki_list))
1453 aio_remove_iocb(iocb);
1454
1455 if (kiocb->ki_flags & IOCB_WRITE) {
1456 struct inode *inode = file_inode(kiocb->ki_filp);
1457
1458 /*
1459 * Tell lockdep we inherited freeze protection from submission
1460 * thread.
1461 */
1462 if (S_ISREG(inode->i_mode))
1463 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
1464 file_end_write(kiocb->ki_filp);
1465 }
1466
1467 iocb->ki_res.res = res;
1468 iocb->ki_res.res2 = 0;
1469 iocb_put(iocb);
1470}
1471
1472static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
1473{
1474 int ret;
1475
1476 req->ki_complete = aio_complete_rw;
1477 req->private = NULL;
1478 req->ki_pos = iocb->aio_offset;
1479 req->ki_flags = req->ki_filp->f_iocb_flags;
1480 if (iocb->aio_flags & IOCB_FLAG_RESFD)
1481 req->ki_flags |= IOCB_EVENTFD;
1482 if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
1483 /*
1484 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
1485 * aio_reqprio is interpreted as an I/O scheduling
1486 * class and priority.
1487 */
1488 ret = ioprio_check_cap(iocb->aio_reqprio);
1489 if (ret) {
1490 pr_debug("aio ioprio check cap error: %d\n", ret);
1491 return ret;
1492 }
1493
1494 req->ki_ioprio = iocb->aio_reqprio;
1495 } else
1496 req->ki_ioprio = get_current_ioprio();
1497
1498 ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
1499 if (unlikely(ret))
1500 return ret;
1501
1502 req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
1503 return 0;
1504}
1505
1506static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
1507 struct iovec **iovec, bool vectored, bool compat,
1508 struct iov_iter *iter)
1509{
1510 void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
1511 size_t len = iocb->aio_nbytes;
1512
1513 if (!vectored) {
1514 ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
1515 *iovec = NULL;
1516 return ret;
1517 }
1518
1519 return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
1520}
1521
1522static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
1523{
1524 switch (ret) {
1525 case -EIOCBQUEUED:
1526 break;
1527 case -ERESTARTSYS:
1528 case -ERESTARTNOINTR:
1529 case -ERESTARTNOHAND:
1530 case -ERESTART_RESTARTBLOCK:
1531 /*
1532 * There's no easy way to restart the syscall since other AIO's
1533 * may be already running. Just fail this IO with EINTR.
1534 */
1535 ret = -EINTR;
1536 fallthrough;
1537 default:
1538 req->ki_complete(req, ret);
1539 }
1540}
1541
1542static int aio_read(struct kiocb *req, const struct iocb *iocb,
1543 bool vectored, bool compat)
1544{
1545 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1546 struct iov_iter iter;
1547 struct file *file;
1548 int ret;
1549
1550 ret = aio_prep_rw(req, iocb);
1551 if (ret)
1552 return ret;
1553 file = req->ki_filp;
1554 if (unlikely(!(file->f_mode & FMODE_READ)))
1555 return -EBADF;
1556 if (unlikely(!file->f_op->read_iter))
1557 return -EINVAL;
1558
1559 ret = aio_setup_rw(ITER_DEST, iocb, &iovec, vectored, compat, &iter);
1560 if (ret < 0)
1561 return ret;
1562 ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
1563 if (!ret)
1564 aio_rw_done(req, call_read_iter(file, req, &iter));
1565 kfree(iovec);
1566 return ret;
1567}
1568
1569static int aio_write(struct kiocb *req, const struct iocb *iocb,
1570 bool vectored, bool compat)
1571{
1572 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1573 struct iov_iter iter;
1574 struct file *file;
1575 int ret;
1576
1577 ret = aio_prep_rw(req, iocb);
1578 if (ret)
1579 return ret;
1580 file = req->ki_filp;
1581
1582 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1583 return -EBADF;
1584 if (unlikely(!file->f_op->write_iter))
1585 return -EINVAL;
1586
1587 ret = aio_setup_rw(ITER_SOURCE, iocb, &iovec, vectored, compat, &iter);
1588 if (ret < 0)
1589 return ret;
1590 ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
1591 if (!ret) {
1592 /*
1593 * Open-code file_start_write here to grab freeze protection,
1594 * which will be released by another thread in
1595 * aio_complete_rw(). Fool lockdep by telling it the lock got
1596 * released so that it doesn't complain about the held lock when
1597 * we return to userspace.
1598 */
1599 if (S_ISREG(file_inode(file)->i_mode)) {
1600 sb_start_write(file_inode(file)->i_sb);
1601 __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
1602 }
1603 req->ki_flags |= IOCB_WRITE;
1604 aio_rw_done(req, call_write_iter(file, req, &iter));
1605 }
1606 kfree(iovec);
1607 return ret;
1608}
1609
1610static void aio_fsync_work(struct work_struct *work)
1611{
1612 struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
1613 const struct cred *old_cred = override_creds(iocb->fsync.creds);
1614
1615 iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
1616 revert_creds(old_cred);
1617 put_cred(iocb->fsync.creds);
1618 iocb_put(iocb);
1619}
1620
1621static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
1622 bool datasync)
1623{
1624 if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
1625 iocb->aio_rw_flags))
1626 return -EINVAL;
1627
1628 if (unlikely(!req->file->f_op->fsync))
1629 return -EINVAL;
1630
1631 req->creds = prepare_creds();
1632 if (!req->creds)
1633 return -ENOMEM;
1634
1635 req->datasync = datasync;
1636 INIT_WORK(&req->work, aio_fsync_work);
1637 schedule_work(&req->work);
1638 return 0;
1639}
1640
1641static void aio_poll_put_work(struct work_struct *work)
1642{
1643 struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1644 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1645
1646 iocb_put(iocb);
1647}
1648
1649/*
1650 * Safely lock the waitqueue which the request is on, synchronizing with the
1651 * case where the ->poll() provider decides to free its waitqueue early.
1652 *
1653 * Returns true on success, meaning that req->head->lock was locked, req->wait
1654 * is on req->head, and an RCU read lock was taken. Returns false if the
1655 * request was already removed from its waitqueue (which might no longer exist).
1656 */
1657static bool poll_iocb_lock_wq(struct poll_iocb *req)
1658{
1659 wait_queue_head_t *head;
1660
1661 /*
1662 * While we hold the waitqueue lock and the waitqueue is nonempty,
1663 * wake_up_pollfree() will wait for us. However, taking the waitqueue
1664 * lock in the first place can race with the waitqueue being freed.
1665 *
1666 * We solve this as eventpoll does: by taking advantage of the fact that
1667 * all users of wake_up_pollfree() will RCU-delay the actual free. If
1668 * we enter rcu_read_lock() and see that the pointer to the queue is
1669 * non-NULL, we can then lock it without the memory being freed out from
1670 * under us, then check whether the request is still on the queue.
1671 *
1672 * Keep holding rcu_read_lock() as long as we hold the queue lock, in
1673 * case the caller deletes the entry from the queue, leaving it empty.
1674 * In that case, only RCU prevents the queue memory from being freed.
1675 */
1676 rcu_read_lock();
1677 head = smp_load_acquire(&req->head);
1678 if (head) {
1679 spin_lock(&head->lock);
1680 if (!list_empty(&req->wait.entry))
1681 return true;
1682 spin_unlock(&head->lock);
1683 }
1684 rcu_read_unlock();
1685 return false;
1686}
1687
1688static void poll_iocb_unlock_wq(struct poll_iocb *req)
1689{
1690 spin_unlock(&req->head->lock);
1691 rcu_read_unlock();
1692}
1693
1694static void aio_poll_complete_work(struct work_struct *work)
1695{
1696 struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1697 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1698 struct poll_table_struct pt = { ._key = req->events };
1699 struct kioctx *ctx = iocb->ki_ctx;
1700 __poll_t mask = 0;
1701
1702 if (!READ_ONCE(req->cancelled))
1703 mask = vfs_poll(req->file, &pt) & req->events;
1704
1705 /*
1706 * Note that ->ki_cancel callers also delete iocb from active_reqs after
1707 * calling ->ki_cancel. We need the ctx_lock roundtrip here to
1708 * synchronize with them. In the cancellation case the list_del_init
1709 * itself is not actually needed, but harmless so we keep it in to
1710 * avoid further branches in the fast path.
1711 */
1712 spin_lock_irq(&ctx->ctx_lock);
1713 if (poll_iocb_lock_wq(req)) {
1714 if (!mask && !READ_ONCE(req->cancelled)) {
1715 /*
1716 * The request isn't actually ready to be completed yet.
1717 * Reschedule completion if another wakeup came in.
1718 */
1719 if (req->work_need_resched) {
1720 schedule_work(&req->work);
1721 req->work_need_resched = false;
1722 } else {
1723 req->work_scheduled = false;
1724 }
1725 poll_iocb_unlock_wq(req);
1726 spin_unlock_irq(&ctx->ctx_lock);
1727 return;
1728 }
1729 list_del_init(&req->wait.entry);
1730 poll_iocb_unlock_wq(req);
1731 } /* else, POLLFREE has freed the waitqueue, so we must complete */
1732 list_del_init(&iocb->ki_list);
1733 iocb->ki_res.res = mangle_poll(mask);
1734 spin_unlock_irq(&ctx->ctx_lock);
1735
1736 iocb_put(iocb);
1737}
1738
1739/* assumes we are called with irqs disabled */
1740static int aio_poll_cancel(struct kiocb *iocb)
1741{
1742 struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
1743 struct poll_iocb *req = &aiocb->poll;
1744
1745 if (poll_iocb_lock_wq(req)) {
1746 WRITE_ONCE(req->cancelled, true);
1747 if (!req->work_scheduled) {
1748 schedule_work(&aiocb->poll.work);
1749 req->work_scheduled = true;
1750 }
1751 poll_iocb_unlock_wq(req);
1752 } /* else, the request was force-cancelled by POLLFREE already */
1753
1754 return 0;
1755}
1756
1757static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
1758 void *key)
1759{
1760 struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
1761 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1762 __poll_t mask = key_to_poll(key);
1763 unsigned long flags;
1764
1765 /* for instances that support it check for an event match first: */
1766 if (mask && !(mask & req->events))
1767 return 0;
1768
1769 /*
1770 * Complete the request inline if possible. This requires that three
1771 * conditions be met:
1772 * 1. An event mask must have been passed. If a plain wakeup was done
1773 * instead, then mask == 0 and we have to call vfs_poll() to get
1774 * the events, so inline completion isn't possible.
1775 * 2. The completion work must not have already been scheduled.
1776 * 3. ctx_lock must not be busy. We have to use trylock because we
1777 * already hold the waitqueue lock, so this inverts the normal
1778 * locking order. Use irqsave/irqrestore because not all
1779 * filesystems (e.g. fuse) call this function with IRQs disabled,
1780 * yet IRQs have to be disabled before ctx_lock is obtained.
1781 */
1782 if (mask && !req->work_scheduled &&
1783 spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
1784 struct kioctx *ctx = iocb->ki_ctx;
1785
1786 list_del_init(&req->wait.entry);
1787 list_del(&iocb->ki_list);
1788 iocb->ki_res.res = mangle_poll(mask);
1789 if (iocb->ki_eventfd && !eventfd_signal_allowed()) {
1790 iocb = NULL;
1791 INIT_WORK(&req->work, aio_poll_put_work);
1792 schedule_work(&req->work);
1793 }
1794 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1795 if (iocb)
1796 iocb_put(iocb);
1797 } else {
1798 /*
1799 * Schedule the completion work if needed. If it was already
1800 * scheduled, record that another wakeup came in.
1801 *
1802 * Don't remove the request from the waitqueue here, as it might
1803 * not actually be complete yet (we won't know until vfs_poll()
1804 * is called), and we must not miss any wakeups. POLLFREE is an
1805 * exception to this; see below.
1806 */
1807 if (req->work_scheduled) {
1808 req->work_need_resched = true;
1809 } else {
1810 schedule_work(&req->work);
1811 req->work_scheduled = true;
1812 }
1813
1814 /*
1815 * If the waitqueue is being freed early but we can't complete
1816 * the request inline, we have to tear down the request as best
1817 * we can. That means immediately removing the request from its
1818 * waitqueue and preventing all further accesses to the
1819 * waitqueue via the request. We also need to schedule the
1820 * completion work (done above). Also mark the request as
1821 * cancelled, to potentially skip an unneeded call to ->poll().
1822 */
1823 if (mask & POLLFREE) {
1824 WRITE_ONCE(req->cancelled, true);
1825 list_del_init(&req->wait.entry);
1826
1827 /*
1828 * Careful: this *must* be the last step, since as soon
1829 * as req->head is NULL'ed out, the request can be
1830 * completed and freed, since aio_poll_complete_work()
1831 * will no longer need to take the waitqueue lock.
1832 */
1833 smp_store_release(&req->head, NULL);
1834 }
1835 }
1836 return 1;
1837}
1838
1839struct aio_poll_table {
1840 struct poll_table_struct pt;
1841 struct aio_kiocb *iocb;
1842 bool queued;
1843 int error;
1844};
1845
1846static void
1847aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
1848 struct poll_table_struct *p)
1849{
1850 struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
1851
1852 /* multiple wait queues per file are not supported */
1853 if (unlikely(pt->queued)) {
1854 pt->error = -EINVAL;
1855 return;
1856 }
1857
1858 pt->queued = true;
1859 pt->error = 0;
1860 pt->iocb->poll.head = head;
1861 add_wait_queue(head, &pt->iocb->poll.wait);
1862}
1863
1864static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
1865{
1866 struct kioctx *ctx = aiocb->ki_ctx;
1867 struct poll_iocb *req = &aiocb->poll;
1868 struct aio_poll_table apt;
1869 bool cancel = false;
1870 __poll_t mask;
1871
1872 /* reject any unknown events outside the normal event mask. */
1873 if ((u16)iocb->aio_buf != iocb->aio_buf)
1874 return -EINVAL;
1875 /* reject fields that are not defined for poll */
1876 if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
1877 return -EINVAL;
1878
1879 INIT_WORK(&req->work, aio_poll_complete_work);
1880 req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
1881
1882 req->head = NULL;
1883 req->cancelled = false;
1884 req->work_scheduled = false;
1885 req->work_need_resched = false;
1886
1887 apt.pt._qproc = aio_poll_queue_proc;
1888 apt.pt._key = req->events;
1889 apt.iocb = aiocb;
1890 apt.queued = false;
1891 apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
1892
1893 /* initialized the list so that we can do list_empty checks */
1894 INIT_LIST_HEAD(&req->wait.entry);
1895 init_waitqueue_func_entry(&req->wait, aio_poll_wake);
1896
1897 mask = vfs_poll(req->file, &apt.pt) & req->events;
1898 spin_lock_irq(&ctx->ctx_lock);
1899 if (likely(apt.queued)) {
1900 bool on_queue = poll_iocb_lock_wq(req);
1901
1902 if (!on_queue || req->work_scheduled) {
1903 /*
1904 * aio_poll_wake() already either scheduled the async
1905 * completion work, or completed the request inline.
1906 */
1907 if (apt.error) /* unsupported case: multiple queues */
1908 cancel = true;
1909 apt.error = 0;
1910 mask = 0;
1911 }
1912 if (mask || apt.error) {
1913 /* Steal to complete synchronously. */
1914 list_del_init(&req->wait.entry);
1915 } else if (cancel) {
1916 /* Cancel if possible (may be too late though). */
1917 WRITE_ONCE(req->cancelled, true);
1918 } else if (on_queue) {
1919 /*
1920 * Actually waiting for an event, so add the request to
1921 * active_reqs so that it can be cancelled if needed.
1922 */
1923 list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
1924 aiocb->ki_cancel = aio_poll_cancel;
1925 }
1926 if (on_queue)
1927 poll_iocb_unlock_wq(req);
1928 }
1929 if (mask) { /* no async, we'd stolen it */
1930 aiocb->ki_res.res = mangle_poll(mask);
1931 apt.error = 0;
1932 }
1933 spin_unlock_irq(&ctx->ctx_lock);
1934 if (mask)
1935 iocb_put(aiocb);
1936 return apt.error;
1937}
1938
1939static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
1940 struct iocb __user *user_iocb, struct aio_kiocb *req,
1941 bool compat)
1942{
1943 req->ki_filp = fget(iocb->aio_fildes);
1944 if (unlikely(!req->ki_filp))
1945 return -EBADF;
1946
1947 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1948 struct eventfd_ctx *eventfd;
1949 /*
1950 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1951 * instance of the file* now. The file descriptor must be
1952 * an eventfd() fd, and will be signaled for each completed
1953 * event using the eventfd_signal() function.
1954 */
1955 eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
1956 if (IS_ERR(eventfd))
1957 return PTR_ERR(eventfd);
1958
1959 req->ki_eventfd = eventfd;
1960 }
1961
1962 if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
1963 pr_debug("EFAULT: aio_key\n");
1964 return -EFAULT;
1965 }
1966
1967 req->ki_res.obj = (u64)(unsigned long)user_iocb;
1968 req->ki_res.data = iocb->aio_data;
1969 req->ki_res.res = 0;
1970 req->ki_res.res2 = 0;
1971
1972 switch (iocb->aio_lio_opcode) {
1973 case IOCB_CMD_PREAD:
1974 return aio_read(&req->rw, iocb, false, compat);
1975 case IOCB_CMD_PWRITE:
1976 return aio_write(&req->rw, iocb, false, compat);
1977 case IOCB_CMD_PREADV:
1978 return aio_read(&req->rw, iocb, true, compat);
1979 case IOCB_CMD_PWRITEV:
1980 return aio_write(&req->rw, iocb, true, compat);
1981 case IOCB_CMD_FSYNC:
1982 return aio_fsync(&req->fsync, iocb, false);
1983 case IOCB_CMD_FDSYNC:
1984 return aio_fsync(&req->fsync, iocb, true);
1985 case IOCB_CMD_POLL:
1986 return aio_poll(req, iocb);
1987 default:
1988 pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
1989 return -EINVAL;
1990 }
1991}
1992
1993static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1994 bool compat)
1995{
1996 struct aio_kiocb *req;
1997 struct iocb iocb;
1998 int err;
1999
2000 if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
2001 return -EFAULT;
2002
2003 /* enforce forwards compatibility on users */
2004 if (unlikely(iocb.aio_reserved2)) {
2005 pr_debug("EINVAL: reserve field set\n");
2006 return -EINVAL;
2007 }
2008
2009 /* prevent overflows */
2010 if (unlikely(
2011 (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
2012 (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
2013 ((ssize_t)iocb.aio_nbytes < 0)
2014 )) {
2015 pr_debug("EINVAL: overflow check\n");
2016 return -EINVAL;
2017 }
2018
2019 req = aio_get_req(ctx);
2020 if (unlikely(!req))
2021 return -EAGAIN;
2022
2023 err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
2024
2025 /* Done with the synchronous reference */
2026 iocb_put(req);
2027
2028 /*
2029 * If err is 0, we'd either done aio_complete() ourselves or have
2030 * arranged for that to be done asynchronously. Anything non-zero
2031 * means that we need to destroy req ourselves.
2032 */
2033 if (unlikely(err)) {
2034 iocb_destroy(req);
2035 put_reqs_available(ctx, 1);
2036 }
2037 return err;
2038}
2039
2040/* sys_io_submit:
2041 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
2042 * the number of iocbs queued. May return -EINVAL if the aio_context
2043 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
2044 * *iocbpp[0] is not properly initialized, if the operation specified
2045 * is invalid for the file descriptor in the iocb. May fail with
2046 * -EFAULT if any of the data structures point to invalid data. May
2047 * fail with -EBADF if the file descriptor specified in the first
2048 * iocb is invalid. May fail with -EAGAIN if insufficient resources
2049 * are available to queue any iocbs. Will return 0 if nr is 0. Will
2050 * fail with -ENOSYS if not implemented.
2051 */
2052SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
2053 struct iocb __user * __user *, iocbpp)
2054{
2055 struct kioctx *ctx;
2056 long ret = 0;
2057 int i = 0;
2058 struct blk_plug plug;
2059
2060 if (unlikely(nr < 0))
2061 return -EINVAL;
2062
2063 ctx = lookup_ioctx(ctx_id);
2064 if (unlikely(!ctx)) {
2065 pr_debug("EINVAL: invalid context id\n");
2066 return -EINVAL;
2067 }
2068
2069 if (nr > ctx->nr_events)
2070 nr = ctx->nr_events;
2071
2072 if (nr > AIO_PLUG_THRESHOLD)
2073 blk_start_plug(&plug);
2074 for (i = 0; i < nr; i++) {
2075 struct iocb __user *user_iocb;
2076
2077 if (unlikely(get_user(user_iocb, iocbpp + i))) {
2078 ret = -EFAULT;
2079 break;
2080 }
2081
2082 ret = io_submit_one(ctx, user_iocb, false);
2083 if (ret)
2084 break;
2085 }
2086 if (nr > AIO_PLUG_THRESHOLD)
2087 blk_finish_plug(&plug);
2088
2089 percpu_ref_put(&ctx->users);
2090 return i ? i : ret;
2091}
2092
2093#ifdef CONFIG_COMPAT
2094COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
2095 int, nr, compat_uptr_t __user *, iocbpp)
2096{
2097 struct kioctx *ctx;
2098 long ret = 0;
2099 int i = 0;
2100 struct blk_plug plug;
2101
2102 if (unlikely(nr < 0))
2103 return -EINVAL;
2104
2105 ctx = lookup_ioctx(ctx_id);
2106 if (unlikely(!ctx)) {
2107 pr_debug("EINVAL: invalid context id\n");
2108 return -EINVAL;
2109 }
2110
2111 if (nr > ctx->nr_events)
2112 nr = ctx->nr_events;
2113
2114 if (nr > AIO_PLUG_THRESHOLD)
2115 blk_start_plug(&plug);
2116 for (i = 0; i < nr; i++) {
2117 compat_uptr_t user_iocb;
2118
2119 if (unlikely(get_user(user_iocb, iocbpp + i))) {
2120 ret = -EFAULT;
2121 break;
2122 }
2123
2124 ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
2125 if (ret)
2126 break;
2127 }
2128 if (nr > AIO_PLUG_THRESHOLD)
2129 blk_finish_plug(&plug);
2130
2131 percpu_ref_put(&ctx->users);
2132 return i ? i : ret;
2133}
2134#endif
2135
2136/* sys_io_cancel:
2137 * Attempts to cancel an iocb previously passed to io_submit. If
2138 * the operation is successfully cancelled, the resulting event is
2139 * copied into the memory pointed to by result without being placed
2140 * into the completion queue and 0 is returned. May fail with
2141 * -EFAULT if any of the data structures pointed to are invalid.
2142 * May fail with -EINVAL if aio_context specified by ctx_id is
2143 * invalid. May fail with -EAGAIN if the iocb specified was not
2144 * cancelled. Will fail with -ENOSYS if not implemented.
2145 */
2146SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
2147 struct io_event __user *, result)
2148{
2149 struct kioctx *ctx;
2150 struct aio_kiocb *kiocb;
2151 int ret = -EINVAL;
2152 u32 key;
2153 u64 obj = (u64)(unsigned long)iocb;
2154
2155 if (unlikely(get_user(key, &iocb->aio_key)))
2156 return -EFAULT;
2157 if (unlikely(key != KIOCB_KEY))
2158 return -EINVAL;
2159
2160 ctx = lookup_ioctx(ctx_id);
2161 if (unlikely(!ctx))
2162 return -EINVAL;
2163
2164 spin_lock_irq(&ctx->ctx_lock);
2165 /* TODO: use a hash or array, this sucks. */
2166 list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
2167 if (kiocb->ki_res.obj == obj) {
2168 ret = kiocb->ki_cancel(&kiocb->rw);
2169 list_del_init(&kiocb->ki_list);
2170 break;
2171 }
2172 }
2173 spin_unlock_irq(&ctx->ctx_lock);
2174
2175 if (!ret) {
2176 /*
2177 * The result argument is no longer used - the io_event is
2178 * always delivered via the ring buffer. -EINPROGRESS indicates
2179 * cancellation is progress:
2180 */
2181 ret = -EINPROGRESS;
2182 }
2183
2184 percpu_ref_put(&ctx->users);
2185
2186 return ret;
2187}
2188
2189static long do_io_getevents(aio_context_t ctx_id,
2190 long min_nr,
2191 long nr,
2192 struct io_event __user *events,
2193 struct timespec64 *ts)
2194{
2195 ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
2196 struct kioctx *ioctx = lookup_ioctx(ctx_id);
2197 long ret = -EINVAL;
2198
2199 if (likely(ioctx)) {
2200 if (likely(min_nr <= nr && min_nr >= 0))
2201 ret = read_events(ioctx, min_nr, nr, events, until);
2202 percpu_ref_put(&ioctx->users);
2203 }
2204
2205 return ret;
2206}
2207
2208/* io_getevents:
2209 * Attempts to read at least min_nr events and up to nr events from
2210 * the completion queue for the aio_context specified by ctx_id. If
2211 * it succeeds, the number of read events is returned. May fail with
2212 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
2213 * out of range, if timeout is out of range. May fail with -EFAULT
2214 * if any of the memory specified is invalid. May return 0 or
2215 * < min_nr if the timeout specified by timeout has elapsed
2216 * before sufficient events are available, where timeout == NULL
2217 * specifies an infinite timeout. Note that the timeout pointed to by
2218 * timeout is relative. Will fail with -ENOSYS if not implemented.
2219 */
2220#ifdef CONFIG_64BIT
2221
2222SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
2223 long, min_nr,
2224 long, nr,
2225 struct io_event __user *, events,
2226 struct __kernel_timespec __user *, timeout)
2227{
2228 struct timespec64 ts;
2229 int ret;
2230
2231 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2232 return -EFAULT;
2233
2234 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2235 if (!ret && signal_pending(current))
2236 ret = -EINTR;
2237 return ret;
2238}
2239
2240#endif
2241
2242struct __aio_sigset {
2243 const sigset_t __user *sigmask;
2244 size_t sigsetsize;
2245};
2246
2247SYSCALL_DEFINE6(io_pgetevents,
2248 aio_context_t, ctx_id,
2249 long, min_nr,
2250 long, nr,
2251 struct io_event __user *, events,
2252 struct __kernel_timespec __user *, timeout,
2253 const struct __aio_sigset __user *, usig)
2254{
2255 struct __aio_sigset ksig = { NULL, };
2256 struct timespec64 ts;
2257 bool interrupted;
2258 int ret;
2259
2260 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2261 return -EFAULT;
2262
2263 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2264 return -EFAULT;
2265
2266 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2267 if (ret)
2268 return ret;
2269
2270 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2271
2272 interrupted = signal_pending(current);
2273 restore_saved_sigmask_unless(interrupted);
2274 if (interrupted && !ret)
2275 ret = -ERESTARTNOHAND;
2276
2277 return ret;
2278}
2279
2280#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
2281
2282SYSCALL_DEFINE6(io_pgetevents_time32,
2283 aio_context_t, ctx_id,
2284 long, min_nr,
2285 long, nr,
2286 struct io_event __user *, events,
2287 struct old_timespec32 __user *, timeout,
2288 const struct __aio_sigset __user *, usig)
2289{
2290 struct __aio_sigset ksig = { NULL, };
2291 struct timespec64 ts;
2292 bool interrupted;
2293 int ret;
2294
2295 if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
2296 return -EFAULT;
2297
2298 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2299 return -EFAULT;
2300
2301
2302 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2303 if (ret)
2304 return ret;
2305
2306 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2307
2308 interrupted = signal_pending(current);
2309 restore_saved_sigmask_unless(interrupted);
2310 if (interrupted && !ret)
2311 ret = -ERESTARTNOHAND;
2312
2313 return ret;
2314}
2315
2316#endif
2317
2318#if defined(CONFIG_COMPAT_32BIT_TIME)
2319
2320SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
2321 __s32, min_nr,
2322 __s32, nr,
2323 struct io_event __user *, events,
2324 struct old_timespec32 __user *, timeout)
2325{
2326 struct timespec64 t;
2327 int ret;
2328
2329 if (timeout && get_old_timespec32(&t, timeout))
2330 return -EFAULT;
2331
2332 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2333 if (!ret && signal_pending(current))
2334 ret = -EINTR;
2335 return ret;
2336}
2337
2338#endif
2339
2340#ifdef CONFIG_COMPAT
2341
2342struct __compat_aio_sigset {
2343 compat_uptr_t sigmask;
2344 compat_size_t sigsetsize;
2345};
2346
2347#if defined(CONFIG_COMPAT_32BIT_TIME)
2348
2349COMPAT_SYSCALL_DEFINE6(io_pgetevents,
2350 compat_aio_context_t, ctx_id,
2351 compat_long_t, min_nr,
2352 compat_long_t, nr,
2353 struct io_event __user *, events,
2354 struct old_timespec32 __user *, timeout,
2355 const struct __compat_aio_sigset __user *, usig)
2356{
2357 struct __compat_aio_sigset ksig = { 0, };
2358 struct timespec64 t;
2359 bool interrupted;
2360 int ret;
2361
2362 if (timeout && get_old_timespec32(&t, timeout))
2363 return -EFAULT;
2364
2365 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2366 return -EFAULT;
2367
2368 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2369 if (ret)
2370 return ret;
2371
2372 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2373
2374 interrupted = signal_pending(current);
2375 restore_saved_sigmask_unless(interrupted);
2376 if (interrupted && !ret)
2377 ret = -ERESTARTNOHAND;
2378
2379 return ret;
2380}
2381
2382#endif
2383
2384COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
2385 compat_aio_context_t, ctx_id,
2386 compat_long_t, min_nr,
2387 compat_long_t, nr,
2388 struct io_event __user *, events,
2389 struct __kernel_timespec __user *, timeout,
2390 const struct __compat_aio_sigset __user *, usig)
2391{
2392 struct __compat_aio_sigset ksig = { 0, };
2393 struct timespec64 t;
2394 bool interrupted;
2395 int ret;
2396
2397 if (timeout && get_timespec64(&t, timeout))
2398 return -EFAULT;
2399
2400 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2401 return -EFAULT;
2402
2403 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2404 if (ret)
2405 return ret;
2406
2407 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2408
2409 interrupted = signal_pending(current);
2410 restore_saved_sigmask_unless(interrupted);
2411 if (interrupted && !ret)
2412 ret = -ERESTARTNOHAND;
2413
2414 return ret;
2415}
2416#endif