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/mmu_context.h>
31#include <linux/percpu.h>
32#include <linux/slab.h>
33#include <linux/timer.h>
34#include <linux/aio.h>
35#include <linux/highmem.h>
36#include <linux/workqueue.h>
37#include <linux/security.h>
38#include <linux/eventfd.h>
39#include <linux/blkdev.h>
40#include <linux/compat.h>
41#include <linux/migrate.h>
42#include <linux/ramfs.h>
43#include <linux/percpu-refcount.h>
44#include <linux/mount.h>
45
46#include <asm/kmap_types.h>
47#include <linux/uaccess.h>
48#include <linux/nospec.h>
49
50#include "internal.h"
51
52#define KIOCB_KEY 0
53
54#define AIO_RING_MAGIC 0xa10a10a1
55#define AIO_RING_COMPAT_FEATURES 1
56#define AIO_RING_INCOMPAT_FEATURES 0
57struct aio_ring {
58 unsigned id; /* kernel internal index number */
59 unsigned nr; /* number of io_events */
60 unsigned head; /* Written to by userland or under ring_lock
61 * mutex by aio_read_events_ring(). */
62 unsigned tail;
63
64 unsigned magic;
65 unsigned compat_features;
66 unsigned incompat_features;
67 unsigned header_length; /* size of aio_ring */
68
69
70 struct io_event io_events[0];
71}; /* 128 bytes + ring size */
72
73/*
74 * Plugging is meant to work with larger batches of IOs. If we don't
75 * have more than the below, then don't bother setting up a plug.
76 */
77#define AIO_PLUG_THRESHOLD 2
78
79#define AIO_RING_PAGES 8
80
81struct kioctx_table {
82 struct rcu_head rcu;
83 unsigned nr;
84 struct kioctx __rcu *table[];
85};
86
87struct kioctx_cpu {
88 unsigned reqs_available;
89};
90
91struct ctx_rq_wait {
92 struct completion comp;
93 atomic_t count;
94};
95
96struct kioctx {
97 struct percpu_ref users;
98 atomic_t dead;
99
100 struct percpu_ref reqs;
101
102 unsigned long user_id;
103
104 struct __percpu kioctx_cpu *cpu;
105
106 /*
107 * For percpu reqs_available, number of slots we move to/from global
108 * counter at a time:
109 */
110 unsigned req_batch;
111 /*
112 * This is what userspace passed to io_setup(), it's not used for
113 * anything but counting against the global max_reqs quota.
114 *
115 * The real limit is nr_events - 1, which will be larger (see
116 * aio_setup_ring())
117 */
118 unsigned max_reqs;
119
120 /* Size of ringbuffer, in units of struct io_event */
121 unsigned nr_events;
122
123 unsigned long mmap_base;
124 unsigned long mmap_size;
125
126 struct page **ring_pages;
127 long nr_pages;
128
129 struct rcu_work free_rwork; /* see free_ioctx() */
130
131 /*
132 * signals when all in-flight requests are done
133 */
134 struct ctx_rq_wait *rq_wait;
135
136 struct {
137 /*
138 * This counts the number of available slots in the ringbuffer,
139 * so we avoid overflowing it: it's decremented (if positive)
140 * when allocating a kiocb and incremented when the resulting
141 * io_event is pulled off the ringbuffer.
142 *
143 * We batch accesses to it with a percpu version.
144 */
145 atomic_t reqs_available;
146 } ____cacheline_aligned_in_smp;
147
148 struct {
149 spinlock_t ctx_lock;
150 struct list_head active_reqs; /* used for cancellation */
151 } ____cacheline_aligned_in_smp;
152
153 struct {
154 struct mutex ring_lock;
155 wait_queue_head_t wait;
156 } ____cacheline_aligned_in_smp;
157
158 struct {
159 unsigned tail;
160 unsigned completed_events;
161 spinlock_t completion_lock;
162 } ____cacheline_aligned_in_smp;
163
164 struct page *internal_pages[AIO_RING_PAGES];
165 struct file *aio_ring_file;
166
167 unsigned id;
168};
169
170/*
171 * First field must be the file pointer in all the
172 * iocb unions! See also 'struct kiocb' in <linux/fs.h>
173 */
174struct fsync_iocb {
175 struct file *file;
176 struct work_struct work;
177 bool datasync;
178};
179
180struct poll_iocb {
181 struct file *file;
182 struct wait_queue_head *head;
183 __poll_t events;
184 bool woken;
185 bool cancelled;
186 struct wait_queue_entry wait;
187 struct work_struct work;
188};
189
190/*
191 * NOTE! Each of the iocb union members has the file pointer
192 * as the first entry in their struct definition. So you can
193 * access the file pointer through any of the sub-structs,
194 * or directly as just 'ki_filp' in this struct.
195 */
196struct aio_kiocb {
197 union {
198 struct file *ki_filp;
199 struct kiocb rw;
200 struct fsync_iocb fsync;
201 struct poll_iocb poll;
202 };
203
204 struct kioctx *ki_ctx;
205 kiocb_cancel_fn *ki_cancel;
206
207 struct iocb __user *ki_user_iocb; /* user's aiocb */
208 __u64 ki_user_data; /* user's data for completion */
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);
223unsigned long aio_nr; /* current system wide number of aio requests */
224unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
225/*----end sysctl variables---*/
226
227static struct kmem_cache *kiocb_cachep;
228static struct kmem_cache *kioctx_cachep;
229
230static struct vfsmount *aio_mnt;
231
232static const struct file_operations aio_ring_fops;
233static const struct address_space_operations aio_ctx_aops;
234
235static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
236{
237 struct file *file;
238 struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
239 if (IS_ERR(inode))
240 return ERR_CAST(inode);
241
242 inode->i_mapping->a_ops = &aio_ctx_aops;
243 inode->i_mapping->private_data = ctx;
244 inode->i_size = PAGE_SIZE * nr_pages;
245
246 file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
247 O_RDWR, &aio_ring_fops);
248 if (IS_ERR(file))
249 iput(inode);
250 return file;
251}
252
253static struct dentry *aio_mount(struct file_system_type *fs_type,
254 int flags, const char *dev_name, void *data)
255{
256 struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, NULL,
257 AIO_RING_MAGIC);
258
259 if (!IS_ERR(root))
260 root->d_sb->s_iflags |= SB_I_NOEXEC;
261 return root;
262}
263
264/* aio_setup
265 * Creates the slab caches used by the aio routines, panic on
266 * failure as this is done early during the boot sequence.
267 */
268static int __init aio_setup(void)
269{
270 static struct file_system_type aio_fs = {
271 .name = "aio",
272 .mount = aio_mount,
273 .kill_sb = kill_anon_super,
274 };
275 aio_mnt = kern_mount(&aio_fs);
276 if (IS_ERR(aio_mnt))
277 panic("Failed to create aio fs mount.");
278
279 kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
280 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
281 return 0;
282}
283__initcall(aio_setup);
284
285static void put_aio_ring_file(struct kioctx *ctx)
286{
287 struct file *aio_ring_file = ctx->aio_ring_file;
288 struct address_space *i_mapping;
289
290 if (aio_ring_file) {
291 truncate_setsize(file_inode(aio_ring_file), 0);
292
293 /* Prevent further access to the kioctx from migratepages */
294 i_mapping = aio_ring_file->f_mapping;
295 spin_lock(&i_mapping->private_lock);
296 i_mapping->private_data = NULL;
297 ctx->aio_ring_file = NULL;
298 spin_unlock(&i_mapping->private_lock);
299
300 fput(aio_ring_file);
301 }
302}
303
304static void aio_free_ring(struct kioctx *ctx)
305{
306 int i;
307
308 /* Disconnect the kiotx from the ring file. This prevents future
309 * accesses to the kioctx from page migration.
310 */
311 put_aio_ring_file(ctx);
312
313 for (i = 0; i < ctx->nr_pages; i++) {
314 struct page *page;
315 pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
316 page_count(ctx->ring_pages[i]));
317 page = ctx->ring_pages[i];
318 if (!page)
319 continue;
320 ctx->ring_pages[i] = NULL;
321 put_page(page);
322 }
323
324 if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
325 kfree(ctx->ring_pages);
326 ctx->ring_pages = NULL;
327 }
328}
329
330static int aio_ring_mremap(struct vm_area_struct *vma)
331{
332 struct file *file = vma->vm_file;
333 struct mm_struct *mm = vma->vm_mm;
334 struct kioctx_table *table;
335 int i, res = -EINVAL;
336
337 spin_lock(&mm->ioctx_lock);
338 rcu_read_lock();
339 table = rcu_dereference(mm->ioctx_table);
340 for (i = 0; i < table->nr; i++) {
341 struct kioctx *ctx;
342
343 ctx = rcu_dereference(table->table[i]);
344 if (ctx && ctx->aio_ring_file == file) {
345 if (!atomic_read(&ctx->dead)) {
346 ctx->user_id = ctx->mmap_base = vma->vm_start;
347 res = 0;
348 }
349 break;
350 }
351 }
352
353 rcu_read_unlock();
354 spin_unlock(&mm->ioctx_lock);
355 return res;
356}
357
358static const struct vm_operations_struct aio_ring_vm_ops = {
359 .mremap = aio_ring_mremap,
360#if IS_ENABLED(CONFIG_MMU)
361 .fault = filemap_fault,
362 .map_pages = filemap_map_pages,
363 .page_mkwrite = filemap_page_mkwrite,
364#endif
365};
366
367static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
368{
369 vma->vm_flags |= VM_DONTEXPAND;
370 vma->vm_ops = &aio_ring_vm_ops;
371 return 0;
372}
373
374static const struct file_operations aio_ring_fops = {
375 .mmap = aio_ring_mmap,
376};
377
378#if IS_ENABLED(CONFIG_MIGRATION)
379static int aio_migratepage(struct address_space *mapping, struct page *new,
380 struct page *old, enum migrate_mode mode)
381{
382 struct kioctx *ctx;
383 unsigned long flags;
384 pgoff_t idx;
385 int rc;
386
387 /*
388 * We cannot support the _NO_COPY case here, because copy needs to
389 * happen under the ctx->completion_lock. That does not work with the
390 * migration workflow of MIGRATE_SYNC_NO_COPY.
391 */
392 if (mode == MIGRATE_SYNC_NO_COPY)
393 return -EINVAL;
394
395 rc = 0;
396
397 /* mapping->private_lock here protects against the kioctx teardown. */
398 spin_lock(&mapping->private_lock);
399 ctx = mapping->private_data;
400 if (!ctx) {
401 rc = -EINVAL;
402 goto out;
403 }
404
405 /* The ring_lock mutex. The prevents aio_read_events() from writing
406 * to the ring's head, and prevents page migration from mucking in
407 * a partially initialized kiotx.
408 */
409 if (!mutex_trylock(&ctx->ring_lock)) {
410 rc = -EAGAIN;
411 goto out;
412 }
413
414 idx = old->index;
415 if (idx < (pgoff_t)ctx->nr_pages) {
416 /* Make sure the old page hasn't already been changed */
417 if (ctx->ring_pages[idx] != old)
418 rc = -EAGAIN;
419 } else
420 rc = -EINVAL;
421
422 if (rc != 0)
423 goto out_unlock;
424
425 /* Writeback must be complete */
426 BUG_ON(PageWriteback(old));
427 get_page(new);
428
429 rc = migrate_page_move_mapping(mapping, new, old, mode, 1);
430 if (rc != MIGRATEPAGE_SUCCESS) {
431 put_page(new);
432 goto out_unlock;
433 }
434
435 /* Take completion_lock to prevent other writes to the ring buffer
436 * while the old page is copied to the new. This prevents new
437 * events from being lost.
438 */
439 spin_lock_irqsave(&ctx->completion_lock, flags);
440 migrate_page_copy(new, old);
441 BUG_ON(ctx->ring_pages[idx] != old);
442 ctx->ring_pages[idx] = new;
443 spin_unlock_irqrestore(&ctx->completion_lock, flags);
444
445 /* The old page is no longer accessible. */
446 put_page(old);
447
448out_unlock:
449 mutex_unlock(&ctx->ring_lock);
450out:
451 spin_unlock(&mapping->private_lock);
452 return rc;
453}
454#endif
455
456static const struct address_space_operations aio_ctx_aops = {
457 .set_page_dirty = __set_page_dirty_no_writeback,
458#if IS_ENABLED(CONFIG_MIGRATION)
459 .migratepage = aio_migratepage,
460#endif
461};
462
463static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
464{
465 struct aio_ring *ring;
466 struct mm_struct *mm = current->mm;
467 unsigned long size, unused;
468 int nr_pages;
469 int i;
470 struct file *file;
471
472 /* Compensate for the ring buffer's head/tail overlap entry */
473 nr_events += 2; /* 1 is required, 2 for good luck */
474
475 size = sizeof(struct aio_ring);
476 size += sizeof(struct io_event) * nr_events;
477
478 nr_pages = PFN_UP(size);
479 if (nr_pages < 0)
480 return -EINVAL;
481
482 file = aio_private_file(ctx, nr_pages);
483 if (IS_ERR(file)) {
484 ctx->aio_ring_file = NULL;
485 return -ENOMEM;
486 }
487
488 ctx->aio_ring_file = file;
489 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
490 / sizeof(struct io_event);
491
492 ctx->ring_pages = ctx->internal_pages;
493 if (nr_pages > AIO_RING_PAGES) {
494 ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
495 GFP_KERNEL);
496 if (!ctx->ring_pages) {
497 put_aio_ring_file(ctx);
498 return -ENOMEM;
499 }
500 }
501
502 for (i = 0; i < nr_pages; i++) {
503 struct page *page;
504 page = find_or_create_page(file->f_mapping,
505 i, GFP_HIGHUSER | __GFP_ZERO);
506 if (!page)
507 break;
508 pr_debug("pid(%d) page[%d]->count=%d\n",
509 current->pid, i, page_count(page));
510 SetPageUptodate(page);
511 unlock_page(page);
512
513 ctx->ring_pages[i] = page;
514 }
515 ctx->nr_pages = i;
516
517 if (unlikely(i != nr_pages)) {
518 aio_free_ring(ctx);
519 return -ENOMEM;
520 }
521
522 ctx->mmap_size = nr_pages * PAGE_SIZE;
523 pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
524
525 if (down_write_killable(&mm->mmap_sem)) {
526 ctx->mmap_size = 0;
527 aio_free_ring(ctx);
528 return -EINTR;
529 }
530
531 ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
532 PROT_READ | PROT_WRITE,
533 MAP_SHARED, 0, &unused, NULL);
534 up_write(&mm->mmap_sem);
535 if (IS_ERR((void *)ctx->mmap_base)) {
536 ctx->mmap_size = 0;
537 aio_free_ring(ctx);
538 return -ENOMEM;
539 }
540
541 pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
542
543 ctx->user_id = ctx->mmap_base;
544 ctx->nr_events = nr_events; /* trusted copy */
545
546 ring = kmap_atomic(ctx->ring_pages[0]);
547 ring->nr = nr_events; /* user copy */
548 ring->id = ~0U;
549 ring->head = ring->tail = 0;
550 ring->magic = AIO_RING_MAGIC;
551 ring->compat_features = AIO_RING_COMPAT_FEATURES;
552 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
553 ring->header_length = sizeof(struct aio_ring);
554 kunmap_atomic(ring);
555 flush_dcache_page(ctx->ring_pages[0]);
556
557 return 0;
558}
559
560#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
561#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
562#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
563
564void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
565{
566 struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
567 struct kioctx *ctx = req->ki_ctx;
568 unsigned long flags;
569
570 if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
571 return;
572
573 spin_lock_irqsave(&ctx->ctx_lock, flags);
574 list_add_tail(&req->ki_list, &ctx->active_reqs);
575 req->ki_cancel = cancel;
576 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
577}
578EXPORT_SYMBOL(kiocb_set_cancel_fn);
579
580/*
581 * free_ioctx() should be RCU delayed to synchronize against the RCU
582 * protected lookup_ioctx() and also needs process context to call
583 * aio_free_ring(). Use rcu_work.
584 */
585static void free_ioctx(struct work_struct *work)
586{
587 struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
588 free_rwork);
589 pr_debug("freeing %p\n", ctx);
590
591 aio_free_ring(ctx);
592 free_percpu(ctx->cpu);
593 percpu_ref_exit(&ctx->reqs);
594 percpu_ref_exit(&ctx->users);
595 kmem_cache_free(kioctx_cachep, ctx);
596}
597
598static void free_ioctx_reqs(struct percpu_ref *ref)
599{
600 struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
601
602 /* At this point we know that there are no any in-flight requests */
603 if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
604 complete(&ctx->rq_wait->comp);
605
606 /* Synchronize against RCU protected table->table[] dereferences */
607 INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
608 queue_rcu_work(system_wq, &ctx->free_rwork);
609}
610
611/*
612 * When this function runs, the kioctx has been removed from the "hash table"
613 * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
614 * now it's safe to cancel any that need to be.
615 */
616static void free_ioctx_users(struct percpu_ref *ref)
617{
618 struct kioctx *ctx = container_of(ref, struct kioctx, users);
619 struct aio_kiocb *req;
620
621 spin_lock_irq(&ctx->ctx_lock);
622
623 while (!list_empty(&ctx->active_reqs)) {
624 req = list_first_entry(&ctx->active_reqs,
625 struct aio_kiocb, ki_list);
626 req->ki_cancel(&req->rw);
627 list_del_init(&req->ki_list);
628 }
629
630 spin_unlock_irq(&ctx->ctx_lock);
631
632 percpu_ref_kill(&ctx->reqs);
633 percpu_ref_put(&ctx->reqs);
634}
635
636static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
637{
638 unsigned i, new_nr;
639 struct kioctx_table *table, *old;
640 struct aio_ring *ring;
641
642 spin_lock(&mm->ioctx_lock);
643 table = rcu_dereference_raw(mm->ioctx_table);
644
645 while (1) {
646 if (table)
647 for (i = 0; i < table->nr; i++)
648 if (!rcu_access_pointer(table->table[i])) {
649 ctx->id = i;
650 rcu_assign_pointer(table->table[i], ctx);
651 spin_unlock(&mm->ioctx_lock);
652
653 /* While kioctx setup is in progress,
654 * we are protected from page migration
655 * changes ring_pages by ->ring_lock.
656 */
657 ring = kmap_atomic(ctx->ring_pages[0]);
658 ring->id = ctx->id;
659 kunmap_atomic(ring);
660 return 0;
661 }
662
663 new_nr = (table ? table->nr : 1) * 4;
664 spin_unlock(&mm->ioctx_lock);
665
666 table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
667 new_nr, GFP_KERNEL);
668 if (!table)
669 return -ENOMEM;
670
671 table->nr = new_nr;
672
673 spin_lock(&mm->ioctx_lock);
674 old = rcu_dereference_raw(mm->ioctx_table);
675
676 if (!old) {
677 rcu_assign_pointer(mm->ioctx_table, table);
678 } else if (table->nr > old->nr) {
679 memcpy(table->table, old->table,
680 old->nr * sizeof(struct kioctx *));
681
682 rcu_assign_pointer(mm->ioctx_table, table);
683 kfree_rcu(old, rcu);
684 } else {
685 kfree(table);
686 table = old;
687 }
688 }
689}
690
691static void aio_nr_sub(unsigned nr)
692{
693 spin_lock(&aio_nr_lock);
694 if (WARN_ON(aio_nr - nr > aio_nr))
695 aio_nr = 0;
696 else
697 aio_nr -= nr;
698 spin_unlock(&aio_nr_lock);
699}
700
701/* ioctx_alloc
702 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
703 */
704static struct kioctx *ioctx_alloc(unsigned nr_events)
705{
706 struct mm_struct *mm = current->mm;
707 struct kioctx *ctx;
708 int err = -ENOMEM;
709
710 /*
711 * Store the original nr_events -- what userspace passed to io_setup(),
712 * for counting against the global limit -- before it changes.
713 */
714 unsigned int max_reqs = nr_events;
715
716 /*
717 * We keep track of the number of available ringbuffer slots, to prevent
718 * overflow (reqs_available), and we also use percpu counters for this.
719 *
720 * So since up to half the slots might be on other cpu's percpu counters
721 * and unavailable, double nr_events so userspace sees what they
722 * expected: additionally, we move req_batch slots to/from percpu
723 * counters at a time, so make sure that isn't 0:
724 */
725 nr_events = max(nr_events, num_possible_cpus() * 4);
726 nr_events *= 2;
727
728 /* Prevent overflows */
729 if (nr_events > (0x10000000U / sizeof(struct io_event))) {
730 pr_debug("ENOMEM: nr_events too high\n");
731 return ERR_PTR(-EINVAL);
732 }
733
734 if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
735 return ERR_PTR(-EAGAIN);
736
737 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
738 if (!ctx)
739 return ERR_PTR(-ENOMEM);
740
741 ctx->max_reqs = max_reqs;
742
743 spin_lock_init(&ctx->ctx_lock);
744 spin_lock_init(&ctx->completion_lock);
745 mutex_init(&ctx->ring_lock);
746 /* Protect against page migration throughout kiotx setup by keeping
747 * the ring_lock mutex held until setup is complete. */
748 mutex_lock(&ctx->ring_lock);
749 init_waitqueue_head(&ctx->wait);
750
751 INIT_LIST_HEAD(&ctx->active_reqs);
752
753 if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
754 goto err;
755
756 if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
757 goto err;
758
759 ctx->cpu = alloc_percpu(struct kioctx_cpu);
760 if (!ctx->cpu)
761 goto err;
762
763 err = aio_setup_ring(ctx, nr_events);
764 if (err < 0)
765 goto err;
766
767 atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
768 ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
769 if (ctx->req_batch < 1)
770 ctx->req_batch = 1;
771
772 /* limit the number of system wide aios */
773 spin_lock(&aio_nr_lock);
774 if (aio_nr + ctx->max_reqs > aio_max_nr ||
775 aio_nr + ctx->max_reqs < aio_nr) {
776 spin_unlock(&aio_nr_lock);
777 err = -EAGAIN;
778 goto err_ctx;
779 }
780 aio_nr += ctx->max_reqs;
781 spin_unlock(&aio_nr_lock);
782
783 percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
784 percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
785
786 err = ioctx_add_table(ctx, mm);
787 if (err)
788 goto err_cleanup;
789
790 /* Release the ring_lock mutex now that all setup is complete. */
791 mutex_unlock(&ctx->ring_lock);
792
793 pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
794 ctx, ctx->user_id, mm, ctx->nr_events);
795 return ctx;
796
797err_cleanup:
798 aio_nr_sub(ctx->max_reqs);
799err_ctx:
800 atomic_set(&ctx->dead, 1);
801 if (ctx->mmap_size)
802 vm_munmap(ctx->mmap_base, ctx->mmap_size);
803 aio_free_ring(ctx);
804err:
805 mutex_unlock(&ctx->ring_lock);
806 free_percpu(ctx->cpu);
807 percpu_ref_exit(&ctx->reqs);
808 percpu_ref_exit(&ctx->users);
809 kmem_cache_free(kioctx_cachep, ctx);
810 pr_debug("error allocating ioctx %d\n", err);
811 return ERR_PTR(err);
812}
813
814/* kill_ioctx
815 * Cancels all outstanding aio requests on an aio context. Used
816 * when the processes owning a context have all exited to encourage
817 * the rapid destruction of the kioctx.
818 */
819static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
820 struct ctx_rq_wait *wait)
821{
822 struct kioctx_table *table;
823
824 spin_lock(&mm->ioctx_lock);
825 if (atomic_xchg(&ctx->dead, 1)) {
826 spin_unlock(&mm->ioctx_lock);
827 return -EINVAL;
828 }
829
830 table = rcu_dereference_raw(mm->ioctx_table);
831 WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
832 RCU_INIT_POINTER(table->table[ctx->id], NULL);
833 spin_unlock(&mm->ioctx_lock);
834
835 /* free_ioctx_reqs() will do the necessary RCU synchronization */
836 wake_up_all(&ctx->wait);
837
838 /*
839 * It'd be more correct to do this in free_ioctx(), after all
840 * the outstanding kiocbs have finished - but by then io_destroy
841 * has already returned, so io_setup() could potentially return
842 * -EAGAIN with no ioctxs actually in use (as far as userspace
843 * could tell).
844 */
845 aio_nr_sub(ctx->max_reqs);
846
847 if (ctx->mmap_size)
848 vm_munmap(ctx->mmap_base, ctx->mmap_size);
849
850 ctx->rq_wait = wait;
851 percpu_ref_kill(&ctx->users);
852 return 0;
853}
854
855/*
856 * exit_aio: called when the last user of mm goes away. At this point, there is
857 * no way for any new requests to be submited or any of the io_* syscalls to be
858 * called on the context.
859 *
860 * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
861 * them.
862 */
863void exit_aio(struct mm_struct *mm)
864{
865 struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
866 struct ctx_rq_wait wait;
867 int i, skipped;
868
869 if (!table)
870 return;
871
872 atomic_set(&wait.count, table->nr);
873 init_completion(&wait.comp);
874
875 skipped = 0;
876 for (i = 0; i < table->nr; ++i) {
877 struct kioctx *ctx =
878 rcu_dereference_protected(table->table[i], true);
879
880 if (!ctx) {
881 skipped++;
882 continue;
883 }
884
885 /*
886 * We don't need to bother with munmap() here - exit_mmap(mm)
887 * is coming and it'll unmap everything. And we simply can't,
888 * this is not necessarily our ->mm.
889 * Since kill_ioctx() uses non-zero ->mmap_size as indicator
890 * that it needs to unmap the area, just set it to 0.
891 */
892 ctx->mmap_size = 0;
893 kill_ioctx(mm, ctx, &wait);
894 }
895
896 if (!atomic_sub_and_test(skipped, &wait.count)) {
897 /* Wait until all IO for the context are done. */
898 wait_for_completion(&wait.comp);
899 }
900
901 RCU_INIT_POINTER(mm->ioctx_table, NULL);
902 kfree(table);
903}
904
905static void put_reqs_available(struct kioctx *ctx, unsigned nr)
906{
907 struct kioctx_cpu *kcpu;
908 unsigned long flags;
909
910 local_irq_save(flags);
911 kcpu = this_cpu_ptr(ctx->cpu);
912 kcpu->reqs_available += nr;
913
914 while (kcpu->reqs_available >= ctx->req_batch * 2) {
915 kcpu->reqs_available -= ctx->req_batch;
916 atomic_add(ctx->req_batch, &ctx->reqs_available);
917 }
918
919 local_irq_restore(flags);
920}
921
922static bool __get_reqs_available(struct kioctx *ctx)
923{
924 struct kioctx_cpu *kcpu;
925 bool ret = false;
926 unsigned long flags;
927
928 local_irq_save(flags);
929 kcpu = this_cpu_ptr(ctx->cpu);
930 if (!kcpu->reqs_available) {
931 int old, avail = atomic_read(&ctx->reqs_available);
932
933 do {
934 if (avail < ctx->req_batch)
935 goto out;
936
937 old = avail;
938 avail = atomic_cmpxchg(&ctx->reqs_available,
939 avail, avail - ctx->req_batch);
940 } while (avail != old);
941
942 kcpu->reqs_available += ctx->req_batch;
943 }
944
945 ret = true;
946 kcpu->reqs_available--;
947out:
948 local_irq_restore(flags);
949 return ret;
950}
951
952/* refill_reqs_available
953 * Updates the reqs_available reference counts used for tracking the
954 * number of free slots in the completion ring. This can be called
955 * from aio_complete() (to optimistically update reqs_available) or
956 * from aio_get_req() (the we're out of events case). It must be
957 * called holding ctx->completion_lock.
958 */
959static void refill_reqs_available(struct kioctx *ctx, unsigned head,
960 unsigned tail)
961{
962 unsigned events_in_ring, completed;
963
964 /* Clamp head since userland can write to it. */
965 head %= ctx->nr_events;
966 if (head <= tail)
967 events_in_ring = tail - head;
968 else
969 events_in_ring = ctx->nr_events - (head - tail);
970
971 completed = ctx->completed_events;
972 if (events_in_ring < completed)
973 completed -= events_in_ring;
974 else
975 completed = 0;
976
977 if (!completed)
978 return;
979
980 ctx->completed_events -= completed;
981 put_reqs_available(ctx, completed);
982}
983
984/* user_refill_reqs_available
985 * Called to refill reqs_available when aio_get_req() encounters an
986 * out of space in the completion ring.
987 */
988static void user_refill_reqs_available(struct kioctx *ctx)
989{
990 spin_lock_irq(&ctx->completion_lock);
991 if (ctx->completed_events) {
992 struct aio_ring *ring;
993 unsigned head;
994
995 /* Access of ring->head may race with aio_read_events_ring()
996 * here, but that's okay since whether we read the old version
997 * or the new version, and either will be valid. The important
998 * part is that head cannot pass tail since we prevent
999 * aio_complete() from updating tail by holding
1000 * ctx->completion_lock. Even if head is invalid, the check
1001 * against ctx->completed_events below will make sure we do the
1002 * safe/right thing.
1003 */
1004 ring = kmap_atomic(ctx->ring_pages[0]);
1005 head = ring->head;
1006 kunmap_atomic(ring);
1007
1008 refill_reqs_available(ctx, head, ctx->tail);
1009 }
1010
1011 spin_unlock_irq(&ctx->completion_lock);
1012}
1013
1014static bool get_reqs_available(struct kioctx *ctx)
1015{
1016 if (__get_reqs_available(ctx))
1017 return true;
1018 user_refill_reqs_available(ctx);
1019 return __get_reqs_available(ctx);
1020}
1021
1022/* aio_get_req
1023 * Allocate a slot for an aio request.
1024 * Returns NULL if no requests are free.
1025 */
1026static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
1027{
1028 struct aio_kiocb *req;
1029
1030 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
1031 if (unlikely(!req))
1032 return NULL;
1033
1034 percpu_ref_get(&ctx->reqs);
1035 req->ki_ctx = ctx;
1036 INIT_LIST_HEAD(&req->ki_list);
1037 refcount_set(&req->ki_refcnt, 0);
1038 req->ki_eventfd = NULL;
1039 return req;
1040}
1041
1042static struct kioctx *lookup_ioctx(unsigned long ctx_id)
1043{
1044 struct aio_ring __user *ring = (void __user *)ctx_id;
1045 struct mm_struct *mm = current->mm;
1046 struct kioctx *ctx, *ret = NULL;
1047 struct kioctx_table *table;
1048 unsigned id;
1049
1050 if (get_user(id, &ring->id))
1051 return NULL;
1052
1053 rcu_read_lock();
1054 table = rcu_dereference(mm->ioctx_table);
1055
1056 if (!table || id >= table->nr)
1057 goto out;
1058
1059 id = array_index_nospec(id, table->nr);
1060 ctx = rcu_dereference(table->table[id]);
1061 if (ctx && ctx->user_id == ctx_id) {
1062 if (percpu_ref_tryget_live(&ctx->users))
1063 ret = ctx;
1064 }
1065out:
1066 rcu_read_unlock();
1067 return ret;
1068}
1069
1070static inline void iocb_put(struct aio_kiocb *iocb)
1071{
1072 if (refcount_read(&iocb->ki_refcnt) == 0 ||
1073 refcount_dec_and_test(&iocb->ki_refcnt)) {
1074 if (iocb->ki_filp)
1075 fput(iocb->ki_filp);
1076 percpu_ref_put(&iocb->ki_ctx->reqs);
1077 kmem_cache_free(kiocb_cachep, iocb);
1078 }
1079}
1080
1081static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb,
1082 long res, long res2)
1083{
1084 ev->obj = (u64)(unsigned long)iocb->ki_user_iocb;
1085 ev->data = iocb->ki_user_data;
1086 ev->res = res;
1087 ev->res2 = res2;
1088}
1089
1090/* aio_complete
1091 * Called when the io request on the given iocb is complete.
1092 */
1093static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
1094{
1095 struct kioctx *ctx = iocb->ki_ctx;
1096 struct aio_ring *ring;
1097 struct io_event *ev_page, *event;
1098 unsigned tail, pos, head;
1099 unsigned long flags;
1100
1101 /*
1102 * Add a completion event to the ring buffer. Must be done holding
1103 * ctx->completion_lock to prevent other code from messing with the tail
1104 * pointer since we might be called from irq context.
1105 */
1106 spin_lock_irqsave(&ctx->completion_lock, flags);
1107
1108 tail = ctx->tail;
1109 pos = tail + AIO_EVENTS_OFFSET;
1110
1111 if (++tail >= ctx->nr_events)
1112 tail = 0;
1113
1114 ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1115 event = ev_page + pos % AIO_EVENTS_PER_PAGE;
1116
1117 aio_fill_event(event, iocb, res, res2);
1118
1119 kunmap_atomic(ev_page);
1120 flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1121
1122 pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
1123 ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data,
1124 res, res2);
1125
1126 /* after flagging the request as done, we
1127 * must never even look at it again
1128 */
1129 smp_wmb(); /* make event visible before updating tail */
1130
1131 ctx->tail = tail;
1132
1133 ring = kmap_atomic(ctx->ring_pages[0]);
1134 head = ring->head;
1135 ring->tail = tail;
1136 kunmap_atomic(ring);
1137 flush_dcache_page(ctx->ring_pages[0]);
1138
1139 ctx->completed_events++;
1140 if (ctx->completed_events > 1)
1141 refill_reqs_available(ctx, head, tail);
1142 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1143
1144 pr_debug("added to ring %p at [%u]\n", iocb, tail);
1145
1146 /*
1147 * Check if the user asked us to deliver the result through an
1148 * eventfd. The eventfd_signal() function is safe to be called
1149 * from IRQ context.
1150 */
1151 if (iocb->ki_eventfd) {
1152 eventfd_signal(iocb->ki_eventfd, 1);
1153 eventfd_ctx_put(iocb->ki_eventfd);
1154 }
1155
1156 /*
1157 * We have to order our ring_info tail store above and test
1158 * of the wait list below outside the wait lock. This is
1159 * like in wake_up_bit() where clearing a bit has to be
1160 * ordered with the unlocked test.
1161 */
1162 smp_mb();
1163
1164 if (waitqueue_active(&ctx->wait))
1165 wake_up(&ctx->wait);
1166 iocb_put(iocb);
1167}
1168
1169/* aio_read_events_ring
1170 * Pull an event off of the ioctx's event ring. Returns the number of
1171 * events fetched
1172 */
1173static long aio_read_events_ring(struct kioctx *ctx,
1174 struct io_event __user *event, long nr)
1175{
1176 struct aio_ring *ring;
1177 unsigned head, tail, pos;
1178 long ret = 0;
1179 int copy_ret;
1180
1181 /*
1182 * The mutex can block and wake us up and that will cause
1183 * wait_event_interruptible_hrtimeout() to schedule without sleeping
1184 * and repeat. This should be rare enough that it doesn't cause
1185 * peformance issues. See the comment in read_events() for more detail.
1186 */
1187 sched_annotate_sleep();
1188 mutex_lock(&ctx->ring_lock);
1189
1190 /* Access to ->ring_pages here is protected by ctx->ring_lock. */
1191 ring = kmap_atomic(ctx->ring_pages[0]);
1192 head = ring->head;
1193 tail = ring->tail;
1194 kunmap_atomic(ring);
1195
1196 /*
1197 * Ensure that once we've read the current tail pointer, that
1198 * we also see the events that were stored up to the tail.
1199 */
1200 smp_rmb();
1201
1202 pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
1203
1204 if (head == tail)
1205 goto out;
1206
1207 head %= ctx->nr_events;
1208 tail %= ctx->nr_events;
1209
1210 while (ret < nr) {
1211 long avail;
1212 struct io_event *ev;
1213 struct page *page;
1214
1215 avail = (head <= tail ? tail : ctx->nr_events) - head;
1216 if (head == tail)
1217 break;
1218
1219 pos = head + AIO_EVENTS_OFFSET;
1220 page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
1221 pos %= AIO_EVENTS_PER_PAGE;
1222
1223 avail = min(avail, nr - ret);
1224 avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
1225
1226 ev = kmap(page);
1227 copy_ret = copy_to_user(event + ret, ev + pos,
1228 sizeof(*ev) * avail);
1229 kunmap(page);
1230
1231 if (unlikely(copy_ret)) {
1232 ret = -EFAULT;
1233 goto out;
1234 }
1235
1236 ret += avail;
1237 head += avail;
1238 head %= ctx->nr_events;
1239 }
1240
1241 ring = kmap_atomic(ctx->ring_pages[0]);
1242 ring->head = head;
1243 kunmap_atomic(ring);
1244 flush_dcache_page(ctx->ring_pages[0]);
1245
1246 pr_debug("%li h%u t%u\n", ret, head, tail);
1247out:
1248 mutex_unlock(&ctx->ring_lock);
1249
1250 return ret;
1251}
1252
1253static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
1254 struct io_event __user *event, long *i)
1255{
1256 long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
1257
1258 if (ret > 0)
1259 *i += ret;
1260
1261 if (unlikely(atomic_read(&ctx->dead)))
1262 ret = -EINVAL;
1263
1264 if (!*i)
1265 *i = ret;
1266
1267 return ret < 0 || *i >= min_nr;
1268}
1269
1270static long read_events(struct kioctx *ctx, long min_nr, long nr,
1271 struct io_event __user *event,
1272 ktime_t until)
1273{
1274 long ret = 0;
1275
1276 /*
1277 * Note that aio_read_events() is being called as the conditional - i.e.
1278 * we're calling it after prepare_to_wait() has set task state to
1279 * TASK_INTERRUPTIBLE.
1280 *
1281 * But aio_read_events() can block, and if it blocks it's going to flip
1282 * the task state back to TASK_RUNNING.
1283 *
1284 * This should be ok, provided it doesn't flip the state back to
1285 * TASK_RUNNING and return 0 too much - that causes us to spin. That
1286 * will only happen if the mutex_lock() call blocks, and we then find
1287 * the ringbuffer empty. So in practice we should be ok, but it's
1288 * something to be aware of when touching this code.
1289 */
1290 if (until == 0)
1291 aio_read_events(ctx, min_nr, nr, event, &ret);
1292 else
1293 wait_event_interruptible_hrtimeout(ctx->wait,
1294 aio_read_events(ctx, min_nr, nr, event, &ret),
1295 until);
1296 return ret;
1297}
1298
1299/* sys_io_setup:
1300 * Create an aio_context capable of receiving at least nr_events.
1301 * ctxp must not point to an aio_context that already exists, and
1302 * must be initialized to 0 prior to the call. On successful
1303 * creation of the aio_context, *ctxp is filled in with the resulting
1304 * handle. May fail with -EINVAL if *ctxp is not initialized,
1305 * if the specified nr_events exceeds internal limits. May fail
1306 * with -EAGAIN if the specified nr_events exceeds the user's limit
1307 * of available events. May fail with -ENOMEM if insufficient kernel
1308 * resources are available. May fail with -EFAULT if an invalid
1309 * pointer is passed for ctxp. Will fail with -ENOSYS if not
1310 * implemented.
1311 */
1312SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1313{
1314 struct kioctx *ioctx = NULL;
1315 unsigned long ctx;
1316 long ret;
1317
1318 ret = get_user(ctx, ctxp);
1319 if (unlikely(ret))
1320 goto out;
1321
1322 ret = -EINVAL;
1323 if (unlikely(ctx || nr_events == 0)) {
1324 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1325 ctx, nr_events);
1326 goto out;
1327 }
1328
1329 ioctx = ioctx_alloc(nr_events);
1330 ret = PTR_ERR(ioctx);
1331 if (!IS_ERR(ioctx)) {
1332 ret = put_user(ioctx->user_id, ctxp);
1333 if (ret)
1334 kill_ioctx(current->mm, ioctx, NULL);
1335 percpu_ref_put(&ioctx->users);
1336 }
1337
1338out:
1339 return ret;
1340}
1341
1342#ifdef CONFIG_COMPAT
1343COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
1344{
1345 struct kioctx *ioctx = NULL;
1346 unsigned long ctx;
1347 long ret;
1348
1349 ret = get_user(ctx, ctx32p);
1350 if (unlikely(ret))
1351 goto out;
1352
1353 ret = -EINVAL;
1354 if (unlikely(ctx || nr_events == 0)) {
1355 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1356 ctx, nr_events);
1357 goto out;
1358 }
1359
1360 ioctx = ioctx_alloc(nr_events);
1361 ret = PTR_ERR(ioctx);
1362 if (!IS_ERR(ioctx)) {
1363 /* truncating is ok because it's a user address */
1364 ret = put_user((u32)ioctx->user_id, ctx32p);
1365 if (ret)
1366 kill_ioctx(current->mm, ioctx, NULL);
1367 percpu_ref_put(&ioctx->users);
1368 }
1369
1370out:
1371 return ret;
1372}
1373#endif
1374
1375/* sys_io_destroy:
1376 * Destroy the aio_context specified. May cancel any outstanding
1377 * AIOs and block on completion. Will fail with -ENOSYS if not
1378 * implemented. May fail with -EINVAL if the context pointed to
1379 * is invalid.
1380 */
1381SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1382{
1383 struct kioctx *ioctx = lookup_ioctx(ctx);
1384 if (likely(NULL != ioctx)) {
1385 struct ctx_rq_wait wait;
1386 int ret;
1387
1388 init_completion(&wait.comp);
1389 atomic_set(&wait.count, 1);
1390
1391 /* Pass requests_done to kill_ioctx() where it can be set
1392 * in a thread-safe way. If we try to set it here then we have
1393 * a race condition if two io_destroy() called simultaneously.
1394 */
1395 ret = kill_ioctx(current->mm, ioctx, &wait);
1396 percpu_ref_put(&ioctx->users);
1397
1398 /* Wait until all IO for the context are done. Otherwise kernel
1399 * keep using user-space buffers even if user thinks the context
1400 * is destroyed.
1401 */
1402 if (!ret)
1403 wait_for_completion(&wait.comp);
1404
1405 return ret;
1406 }
1407 pr_debug("EINVAL: invalid context id\n");
1408 return -EINVAL;
1409}
1410
1411static void aio_remove_iocb(struct aio_kiocb *iocb)
1412{
1413 struct kioctx *ctx = iocb->ki_ctx;
1414 unsigned long flags;
1415
1416 spin_lock_irqsave(&ctx->ctx_lock, flags);
1417 list_del(&iocb->ki_list);
1418 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1419}
1420
1421static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
1422{
1423 struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
1424
1425 if (!list_empty_careful(&iocb->ki_list))
1426 aio_remove_iocb(iocb);
1427
1428 if (kiocb->ki_flags & IOCB_WRITE) {
1429 struct inode *inode = file_inode(kiocb->ki_filp);
1430
1431 /*
1432 * Tell lockdep we inherited freeze protection from submission
1433 * thread.
1434 */
1435 if (S_ISREG(inode->i_mode))
1436 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
1437 file_end_write(kiocb->ki_filp);
1438 }
1439
1440 aio_complete(iocb, res, res2);
1441}
1442
1443static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
1444{
1445 int ret;
1446
1447 req->ki_complete = aio_complete_rw;
1448 req->private = NULL;
1449 req->ki_pos = iocb->aio_offset;
1450 req->ki_flags = iocb_flags(req->ki_filp);
1451 if (iocb->aio_flags & IOCB_FLAG_RESFD)
1452 req->ki_flags |= IOCB_EVENTFD;
1453 req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
1454 if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
1455 /*
1456 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
1457 * aio_reqprio is interpreted as an I/O scheduling
1458 * class and priority.
1459 */
1460 ret = ioprio_check_cap(iocb->aio_reqprio);
1461 if (ret) {
1462 pr_debug("aio ioprio check cap error: %d\n", ret);
1463 return ret;
1464 }
1465
1466 req->ki_ioprio = iocb->aio_reqprio;
1467 } else
1468 req->ki_ioprio = get_current_ioprio();
1469
1470 ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
1471 if (unlikely(ret))
1472 return ret;
1473
1474 req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
1475 return 0;
1476}
1477
1478static int aio_setup_rw(int rw, const struct iocb *iocb, struct iovec **iovec,
1479 bool vectored, bool compat, struct iov_iter *iter)
1480{
1481 void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
1482 size_t len = iocb->aio_nbytes;
1483
1484 if (!vectored) {
1485 ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
1486 *iovec = NULL;
1487 return ret;
1488 }
1489#ifdef CONFIG_COMPAT
1490 if (compat)
1491 return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec,
1492 iter);
1493#endif
1494 return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter);
1495}
1496
1497static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
1498{
1499 switch (ret) {
1500 case -EIOCBQUEUED:
1501 break;
1502 case -ERESTARTSYS:
1503 case -ERESTARTNOINTR:
1504 case -ERESTARTNOHAND:
1505 case -ERESTART_RESTARTBLOCK:
1506 /*
1507 * There's no easy way to restart the syscall since other AIO's
1508 * may be already running. Just fail this IO with EINTR.
1509 */
1510 ret = -EINTR;
1511 /*FALLTHRU*/
1512 default:
1513 req->ki_complete(req, ret, 0);
1514 }
1515}
1516
1517static ssize_t aio_read(struct kiocb *req, const struct iocb *iocb,
1518 bool vectored, bool compat)
1519{
1520 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1521 struct iov_iter iter;
1522 struct file *file;
1523 ssize_t ret;
1524
1525 ret = aio_prep_rw(req, iocb);
1526 if (ret)
1527 return ret;
1528 file = req->ki_filp;
1529 if (unlikely(!(file->f_mode & FMODE_READ)))
1530 return -EBADF;
1531 ret = -EINVAL;
1532 if (unlikely(!file->f_op->read_iter))
1533 return -EINVAL;
1534
1535 ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
1536 if (ret)
1537 return ret;
1538 ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
1539 if (!ret)
1540 aio_rw_done(req, call_read_iter(file, req, &iter));
1541 kfree(iovec);
1542 return ret;
1543}
1544
1545static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,
1546 bool vectored, bool compat)
1547{
1548 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1549 struct iov_iter iter;
1550 struct file *file;
1551 ssize_t ret;
1552
1553 ret = aio_prep_rw(req, iocb);
1554 if (ret)
1555 return ret;
1556 file = req->ki_filp;
1557
1558 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1559 return -EBADF;
1560 if (unlikely(!file->f_op->write_iter))
1561 return -EINVAL;
1562
1563 ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
1564 if (ret)
1565 return ret;
1566 ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
1567 if (!ret) {
1568 /*
1569 * Open-code file_start_write here to grab freeze protection,
1570 * which will be released by another thread in
1571 * aio_complete_rw(). Fool lockdep by telling it the lock got
1572 * released so that it doesn't complain about the held lock when
1573 * we return to userspace.
1574 */
1575 if (S_ISREG(file_inode(file)->i_mode)) {
1576 __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
1577 __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
1578 }
1579 req->ki_flags |= IOCB_WRITE;
1580 aio_rw_done(req, call_write_iter(file, req, &iter));
1581 }
1582 kfree(iovec);
1583 return ret;
1584}
1585
1586static void aio_fsync_work(struct work_struct *work)
1587{
1588 struct fsync_iocb *req = container_of(work, struct fsync_iocb, work);
1589 int ret;
1590
1591 ret = vfs_fsync(req->file, req->datasync);
1592 aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
1593}
1594
1595static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
1596 bool datasync)
1597{
1598 if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
1599 iocb->aio_rw_flags))
1600 return -EINVAL;
1601
1602 if (unlikely(!req->file->f_op->fsync))
1603 return -EINVAL;
1604
1605 req->datasync = datasync;
1606 INIT_WORK(&req->work, aio_fsync_work);
1607 schedule_work(&req->work);
1608 return 0;
1609}
1610
1611static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
1612{
1613 aio_complete(iocb, mangle_poll(mask), 0);
1614}
1615
1616static void aio_poll_complete_work(struct work_struct *work)
1617{
1618 struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1619 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1620 struct poll_table_struct pt = { ._key = req->events };
1621 struct kioctx *ctx = iocb->ki_ctx;
1622 __poll_t mask = 0;
1623
1624 if (!READ_ONCE(req->cancelled))
1625 mask = vfs_poll(req->file, &pt) & req->events;
1626
1627 /*
1628 * Note that ->ki_cancel callers also delete iocb from active_reqs after
1629 * calling ->ki_cancel. We need the ctx_lock roundtrip here to
1630 * synchronize with them. In the cancellation case the list_del_init
1631 * itself is not actually needed, but harmless so we keep it in to
1632 * avoid further branches in the fast path.
1633 */
1634 spin_lock_irq(&ctx->ctx_lock);
1635 if (!mask && !READ_ONCE(req->cancelled)) {
1636 add_wait_queue(req->head, &req->wait);
1637 spin_unlock_irq(&ctx->ctx_lock);
1638 return;
1639 }
1640 list_del_init(&iocb->ki_list);
1641 spin_unlock_irq(&ctx->ctx_lock);
1642
1643 aio_poll_complete(iocb, mask);
1644}
1645
1646/* assumes we are called with irqs disabled */
1647static int aio_poll_cancel(struct kiocb *iocb)
1648{
1649 struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
1650 struct poll_iocb *req = &aiocb->poll;
1651
1652 spin_lock(&req->head->lock);
1653 WRITE_ONCE(req->cancelled, true);
1654 if (!list_empty(&req->wait.entry)) {
1655 list_del_init(&req->wait.entry);
1656 schedule_work(&aiocb->poll.work);
1657 }
1658 spin_unlock(&req->head->lock);
1659
1660 return 0;
1661}
1662
1663static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
1664 void *key)
1665{
1666 struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
1667 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1668 __poll_t mask = key_to_poll(key);
1669 unsigned long flags;
1670
1671 req->woken = true;
1672
1673 /* for instances that support it check for an event match first: */
1674 if (mask) {
1675 if (!(mask & req->events))
1676 return 0;
1677
1678 /*
1679 * Try to complete the iocb inline if we can. Use
1680 * irqsave/irqrestore because not all filesystems (e.g. fuse)
1681 * call this function with IRQs disabled and because IRQs
1682 * have to be disabled before ctx_lock is obtained.
1683 */
1684 if (spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
1685 list_del(&iocb->ki_list);
1686 spin_unlock_irqrestore(&iocb->ki_ctx->ctx_lock, flags);
1687
1688 list_del_init(&req->wait.entry);
1689 aio_poll_complete(iocb, mask);
1690 return 1;
1691 }
1692 }
1693
1694 list_del_init(&req->wait.entry);
1695 schedule_work(&req->work);
1696 return 1;
1697}
1698
1699struct aio_poll_table {
1700 struct poll_table_struct pt;
1701 struct aio_kiocb *iocb;
1702 int error;
1703};
1704
1705static void
1706aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
1707 struct poll_table_struct *p)
1708{
1709 struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
1710
1711 /* multiple wait queues per file are not supported */
1712 if (unlikely(pt->iocb->poll.head)) {
1713 pt->error = -EINVAL;
1714 return;
1715 }
1716
1717 pt->error = 0;
1718 pt->iocb->poll.head = head;
1719 add_wait_queue(head, &pt->iocb->poll.wait);
1720}
1721
1722static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
1723{
1724 struct kioctx *ctx = aiocb->ki_ctx;
1725 struct poll_iocb *req = &aiocb->poll;
1726 struct aio_poll_table apt;
1727 __poll_t mask;
1728
1729 /* reject any unknown events outside the normal event mask. */
1730 if ((u16)iocb->aio_buf != iocb->aio_buf)
1731 return -EINVAL;
1732 /* reject fields that are not defined for poll */
1733 if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
1734 return -EINVAL;
1735
1736 INIT_WORK(&req->work, aio_poll_complete_work);
1737 req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
1738
1739 req->head = NULL;
1740 req->woken = false;
1741 req->cancelled = false;
1742
1743 apt.pt._qproc = aio_poll_queue_proc;
1744 apt.pt._key = req->events;
1745 apt.iocb = aiocb;
1746 apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
1747
1748 /* initialized the list so that we can do list_empty checks */
1749 INIT_LIST_HEAD(&req->wait.entry);
1750 init_waitqueue_func_entry(&req->wait, aio_poll_wake);
1751
1752 /* one for removal from waitqueue, one for this function */
1753 refcount_set(&aiocb->ki_refcnt, 2);
1754
1755 mask = vfs_poll(req->file, &apt.pt) & req->events;
1756 if (unlikely(!req->head)) {
1757 /* we did not manage to set up a waitqueue, done */
1758 goto out;
1759 }
1760
1761 spin_lock_irq(&ctx->ctx_lock);
1762 spin_lock(&req->head->lock);
1763 if (req->woken) {
1764 /* wake_up context handles the rest */
1765 mask = 0;
1766 apt.error = 0;
1767 } else if (mask || apt.error) {
1768 /* if we get an error or a mask we are done */
1769 WARN_ON_ONCE(list_empty(&req->wait.entry));
1770 list_del_init(&req->wait.entry);
1771 } else {
1772 /* actually waiting for an event */
1773 list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
1774 aiocb->ki_cancel = aio_poll_cancel;
1775 }
1776 spin_unlock(&req->head->lock);
1777 spin_unlock_irq(&ctx->ctx_lock);
1778
1779out:
1780 if (unlikely(apt.error))
1781 return apt.error;
1782
1783 if (mask)
1784 aio_poll_complete(aiocb, mask);
1785 iocb_put(aiocb);
1786 return 0;
1787}
1788
1789static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
1790 struct iocb __user *user_iocb, bool compat)
1791{
1792 struct aio_kiocb *req;
1793 ssize_t ret;
1794
1795 /* enforce forwards compatibility on users */
1796 if (unlikely(iocb->aio_reserved2)) {
1797 pr_debug("EINVAL: reserve field set\n");
1798 return -EINVAL;
1799 }
1800
1801 /* prevent overflows */
1802 if (unlikely(
1803 (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
1804 (iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
1805 ((ssize_t)iocb->aio_nbytes < 0)
1806 )) {
1807 pr_debug("EINVAL: overflow check\n");
1808 return -EINVAL;
1809 }
1810
1811 if (!get_reqs_available(ctx))
1812 return -EAGAIN;
1813
1814 ret = -EAGAIN;
1815 req = aio_get_req(ctx);
1816 if (unlikely(!req))
1817 goto out_put_reqs_available;
1818
1819 req->ki_filp = fget(iocb->aio_fildes);
1820 ret = -EBADF;
1821 if (unlikely(!req->ki_filp))
1822 goto out_put_req;
1823
1824 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1825 /*
1826 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1827 * instance of the file* now. The file descriptor must be
1828 * an eventfd() fd, and will be signaled for each completed
1829 * event using the eventfd_signal() function.
1830 */
1831 req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
1832 if (IS_ERR(req->ki_eventfd)) {
1833 ret = PTR_ERR(req->ki_eventfd);
1834 req->ki_eventfd = NULL;
1835 goto out_put_req;
1836 }
1837 }
1838
1839 ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
1840 if (unlikely(ret)) {
1841 pr_debug("EFAULT: aio_key\n");
1842 goto out_put_req;
1843 }
1844
1845 req->ki_user_iocb = user_iocb;
1846 req->ki_user_data = iocb->aio_data;
1847
1848 switch (iocb->aio_lio_opcode) {
1849 case IOCB_CMD_PREAD:
1850 ret = aio_read(&req->rw, iocb, false, compat);
1851 break;
1852 case IOCB_CMD_PWRITE:
1853 ret = aio_write(&req->rw, iocb, false, compat);
1854 break;
1855 case IOCB_CMD_PREADV:
1856 ret = aio_read(&req->rw, iocb, true, compat);
1857 break;
1858 case IOCB_CMD_PWRITEV:
1859 ret = aio_write(&req->rw, iocb, true, compat);
1860 break;
1861 case IOCB_CMD_FSYNC:
1862 ret = aio_fsync(&req->fsync, iocb, false);
1863 break;
1864 case IOCB_CMD_FDSYNC:
1865 ret = aio_fsync(&req->fsync, iocb, true);
1866 break;
1867 case IOCB_CMD_POLL:
1868 ret = aio_poll(req, iocb);
1869 break;
1870 default:
1871 pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
1872 ret = -EINVAL;
1873 break;
1874 }
1875
1876 /*
1877 * If ret is 0, we'd either done aio_complete() ourselves or have
1878 * arranged for that to be done asynchronously. Anything non-zero
1879 * means that we need to destroy req ourselves.
1880 */
1881 if (ret)
1882 goto out_put_req;
1883 return 0;
1884out_put_req:
1885 if (req->ki_eventfd)
1886 eventfd_ctx_put(req->ki_eventfd);
1887 iocb_put(req);
1888out_put_reqs_available:
1889 put_reqs_available(ctx, 1);
1890 return ret;
1891}
1892
1893static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1894 bool compat)
1895{
1896 struct iocb iocb;
1897
1898 if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
1899 return -EFAULT;
1900
1901 return __io_submit_one(ctx, &iocb, user_iocb, compat);
1902}
1903
1904/* sys_io_submit:
1905 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1906 * the number of iocbs queued. May return -EINVAL if the aio_context
1907 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1908 * *iocbpp[0] is not properly initialized, if the operation specified
1909 * is invalid for the file descriptor in the iocb. May fail with
1910 * -EFAULT if any of the data structures point to invalid data. May
1911 * fail with -EBADF if the file descriptor specified in the first
1912 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1913 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1914 * fail with -ENOSYS if not implemented.
1915 */
1916SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1917 struct iocb __user * __user *, iocbpp)
1918{
1919 struct kioctx *ctx;
1920 long ret = 0;
1921 int i = 0;
1922 struct blk_plug plug;
1923
1924 if (unlikely(nr < 0))
1925 return -EINVAL;
1926
1927 ctx = lookup_ioctx(ctx_id);
1928 if (unlikely(!ctx)) {
1929 pr_debug("EINVAL: invalid context id\n");
1930 return -EINVAL;
1931 }
1932
1933 if (nr > ctx->nr_events)
1934 nr = ctx->nr_events;
1935
1936 if (nr > AIO_PLUG_THRESHOLD)
1937 blk_start_plug(&plug);
1938 for (i = 0; i < nr; i++) {
1939 struct iocb __user *user_iocb;
1940
1941 if (unlikely(get_user(user_iocb, iocbpp + i))) {
1942 ret = -EFAULT;
1943 break;
1944 }
1945
1946 ret = io_submit_one(ctx, user_iocb, false);
1947 if (ret)
1948 break;
1949 }
1950 if (nr > AIO_PLUG_THRESHOLD)
1951 blk_finish_plug(&plug);
1952
1953 percpu_ref_put(&ctx->users);
1954 return i ? i : ret;
1955}
1956
1957#ifdef CONFIG_COMPAT
1958COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
1959 int, nr, compat_uptr_t __user *, iocbpp)
1960{
1961 struct kioctx *ctx;
1962 long ret = 0;
1963 int i = 0;
1964 struct blk_plug plug;
1965
1966 if (unlikely(nr < 0))
1967 return -EINVAL;
1968
1969 ctx = lookup_ioctx(ctx_id);
1970 if (unlikely(!ctx)) {
1971 pr_debug("EINVAL: invalid context id\n");
1972 return -EINVAL;
1973 }
1974
1975 if (nr > ctx->nr_events)
1976 nr = ctx->nr_events;
1977
1978 if (nr > AIO_PLUG_THRESHOLD)
1979 blk_start_plug(&plug);
1980 for (i = 0; i < nr; i++) {
1981 compat_uptr_t user_iocb;
1982
1983 if (unlikely(get_user(user_iocb, iocbpp + i))) {
1984 ret = -EFAULT;
1985 break;
1986 }
1987
1988 ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
1989 if (ret)
1990 break;
1991 }
1992 if (nr > AIO_PLUG_THRESHOLD)
1993 blk_finish_plug(&plug);
1994
1995 percpu_ref_put(&ctx->users);
1996 return i ? i : ret;
1997}
1998#endif
1999
2000/* lookup_kiocb
2001 * Finds a given iocb for cancellation.
2002 */
2003static struct aio_kiocb *
2004lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb)
2005{
2006 struct aio_kiocb *kiocb;
2007
2008 assert_spin_locked(&ctx->ctx_lock);
2009
2010 /* TODO: use a hash or array, this sucks. */
2011 list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
2012 if (kiocb->ki_user_iocb == iocb)
2013 return kiocb;
2014 }
2015 return NULL;
2016}
2017
2018/* sys_io_cancel:
2019 * Attempts to cancel an iocb previously passed to io_submit. If
2020 * the operation is successfully cancelled, the resulting event is
2021 * copied into the memory pointed to by result without being placed
2022 * into the completion queue and 0 is returned. May fail with
2023 * -EFAULT if any of the data structures pointed to are invalid.
2024 * May fail with -EINVAL if aio_context specified by ctx_id is
2025 * invalid. May fail with -EAGAIN if the iocb specified was not
2026 * cancelled. Will fail with -ENOSYS if not implemented.
2027 */
2028SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
2029 struct io_event __user *, result)
2030{
2031 struct kioctx *ctx;
2032 struct aio_kiocb *kiocb;
2033 int ret = -EINVAL;
2034 u32 key;
2035
2036 if (unlikely(get_user(key, &iocb->aio_key)))
2037 return -EFAULT;
2038 if (unlikely(key != KIOCB_KEY))
2039 return -EINVAL;
2040
2041 ctx = lookup_ioctx(ctx_id);
2042 if (unlikely(!ctx))
2043 return -EINVAL;
2044
2045 spin_lock_irq(&ctx->ctx_lock);
2046 kiocb = lookup_kiocb(ctx, iocb);
2047 if (kiocb) {
2048 ret = kiocb->ki_cancel(&kiocb->rw);
2049 list_del_init(&kiocb->ki_list);
2050 }
2051 spin_unlock_irq(&ctx->ctx_lock);
2052
2053 if (!ret) {
2054 /*
2055 * The result argument is no longer used - the io_event is
2056 * always delivered via the ring buffer. -EINPROGRESS indicates
2057 * cancellation is progress:
2058 */
2059 ret = -EINPROGRESS;
2060 }
2061
2062 percpu_ref_put(&ctx->users);
2063
2064 return ret;
2065}
2066
2067static long do_io_getevents(aio_context_t ctx_id,
2068 long min_nr,
2069 long nr,
2070 struct io_event __user *events,
2071 struct timespec64 *ts)
2072{
2073 ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
2074 struct kioctx *ioctx = lookup_ioctx(ctx_id);
2075 long ret = -EINVAL;
2076
2077 if (likely(ioctx)) {
2078 if (likely(min_nr <= nr && min_nr >= 0))
2079 ret = read_events(ioctx, min_nr, nr, events, until);
2080 percpu_ref_put(&ioctx->users);
2081 }
2082
2083 return ret;
2084}
2085
2086/* io_getevents:
2087 * Attempts to read at least min_nr events and up to nr events from
2088 * the completion queue for the aio_context specified by ctx_id. If
2089 * it succeeds, the number of read events is returned. May fail with
2090 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
2091 * out of range, if timeout is out of range. May fail with -EFAULT
2092 * if any of the memory specified is invalid. May return 0 or
2093 * < min_nr if the timeout specified by timeout has elapsed
2094 * before sufficient events are available, where timeout == NULL
2095 * specifies an infinite timeout. Note that the timeout pointed to by
2096 * timeout is relative. Will fail with -ENOSYS if not implemented.
2097 */
2098#if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT)
2099
2100SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
2101 long, min_nr,
2102 long, nr,
2103 struct io_event __user *, events,
2104 struct __kernel_timespec __user *, timeout)
2105{
2106 struct timespec64 ts;
2107 int ret;
2108
2109 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2110 return -EFAULT;
2111
2112 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2113 if (!ret && signal_pending(current))
2114 ret = -EINTR;
2115 return ret;
2116}
2117
2118#endif
2119
2120struct __aio_sigset {
2121 const sigset_t __user *sigmask;
2122 size_t sigsetsize;
2123};
2124
2125SYSCALL_DEFINE6(io_pgetevents,
2126 aio_context_t, ctx_id,
2127 long, min_nr,
2128 long, nr,
2129 struct io_event __user *, events,
2130 struct __kernel_timespec __user *, timeout,
2131 const struct __aio_sigset __user *, usig)
2132{
2133 struct __aio_sigset ksig = { NULL, };
2134 sigset_t ksigmask, sigsaved;
2135 struct timespec64 ts;
2136 int ret;
2137
2138 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2139 return -EFAULT;
2140
2141 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2142 return -EFAULT;
2143
2144 ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
2145 if (ret)
2146 return ret;
2147
2148 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2149 restore_user_sigmask(ksig.sigmask, &sigsaved);
2150 if (signal_pending(current) && !ret)
2151 ret = -ERESTARTNOHAND;
2152
2153 return ret;
2154}
2155
2156#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
2157
2158SYSCALL_DEFINE6(io_pgetevents_time32,
2159 aio_context_t, ctx_id,
2160 long, min_nr,
2161 long, nr,
2162 struct io_event __user *, events,
2163 struct old_timespec32 __user *, timeout,
2164 const struct __aio_sigset __user *, usig)
2165{
2166 struct __aio_sigset ksig = { NULL, };
2167 sigset_t ksigmask, sigsaved;
2168 struct timespec64 ts;
2169 int ret;
2170
2171 if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
2172 return -EFAULT;
2173
2174 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2175 return -EFAULT;
2176
2177
2178 ret = set_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
2179 if (ret)
2180 return ret;
2181
2182 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2183 restore_user_sigmask(ksig.sigmask, &sigsaved);
2184 if (signal_pending(current) && !ret)
2185 ret = -ERESTARTNOHAND;
2186
2187 return ret;
2188}
2189
2190#endif
2191
2192#if defined(CONFIG_COMPAT_32BIT_TIME)
2193
2194SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
2195 __s32, min_nr,
2196 __s32, nr,
2197 struct io_event __user *, events,
2198 struct old_timespec32 __user *, timeout)
2199{
2200 struct timespec64 t;
2201 int ret;
2202
2203 if (timeout && get_old_timespec32(&t, timeout))
2204 return -EFAULT;
2205
2206 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2207 if (!ret && signal_pending(current))
2208 ret = -EINTR;
2209 return ret;
2210}
2211
2212#endif
2213
2214#ifdef CONFIG_COMPAT
2215
2216struct __compat_aio_sigset {
2217 compat_sigset_t __user *sigmask;
2218 compat_size_t sigsetsize;
2219};
2220
2221#if defined(CONFIG_COMPAT_32BIT_TIME)
2222
2223COMPAT_SYSCALL_DEFINE6(io_pgetevents,
2224 compat_aio_context_t, ctx_id,
2225 compat_long_t, min_nr,
2226 compat_long_t, nr,
2227 struct io_event __user *, events,
2228 struct old_timespec32 __user *, timeout,
2229 const struct __compat_aio_sigset __user *, usig)
2230{
2231 struct __compat_aio_sigset ksig = { NULL, };
2232 sigset_t ksigmask, sigsaved;
2233 struct timespec64 t;
2234 int ret;
2235
2236 if (timeout && get_old_timespec32(&t, timeout))
2237 return -EFAULT;
2238
2239 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2240 return -EFAULT;
2241
2242 ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
2243 if (ret)
2244 return ret;
2245
2246 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2247 restore_user_sigmask(ksig.sigmask, &sigsaved);
2248 if (signal_pending(current) && !ret)
2249 ret = -ERESTARTNOHAND;
2250
2251 return ret;
2252}
2253
2254#endif
2255
2256COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
2257 compat_aio_context_t, ctx_id,
2258 compat_long_t, min_nr,
2259 compat_long_t, nr,
2260 struct io_event __user *, events,
2261 struct __kernel_timespec __user *, timeout,
2262 const struct __compat_aio_sigset __user *, usig)
2263{
2264 struct __compat_aio_sigset ksig = { NULL, };
2265 sigset_t ksigmask, sigsaved;
2266 struct timespec64 t;
2267 int ret;
2268
2269 if (timeout && get_timespec64(&t, timeout))
2270 return -EFAULT;
2271
2272 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2273 return -EFAULT;
2274
2275 ret = set_compat_user_sigmask(ksig.sigmask, &ksigmask, &sigsaved, ksig.sigsetsize);
2276 if (ret)
2277 return ret;
2278
2279 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2280 restore_user_sigmask(ksig.sigmask, &sigsaved);
2281 if (signal_pending(current) && !ret)
2282 ret = -ERESTARTNOHAND;
2283
2284 return ret;
2285}
2286#endif
2287