2 * An async IO implementation for Linux
3 * Written by Benjamin LaHaise <bcrl@kvack.org>
5 * Implements an efficient asynchronous io interface.
7 * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
8 * Copyright 2018 Christoph Hellwig.
10 * See ../COPYING for licensing terms.
12 #define pr_fmt(fmt) "%s: " fmt, __func__
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>
25 #include <linux/sched/signal.h>
27 #include <linux/file.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 #include <linux/pseudo_fs.h>
47 #include <asm/kmap_types.h>
48 #include <linux/uaccess.h>
49 #include <linux/nospec.h>
55 #define AIO_RING_MAGIC 0xa10a10a1
56 #define AIO_RING_COMPAT_FEATURES 1
57 #define AIO_RING_INCOMPAT_FEATURES 0
59 unsigned id; /* kernel internal index number */
60 unsigned nr; /* number of io_events */
61 unsigned head; /* Written to by userland or under ring_lock
62 * mutex by aio_read_events_ring(). */
66 unsigned compat_features;
67 unsigned incompat_features;
68 unsigned header_length; /* size of aio_ring */
71 struct io_event io_events[0];
72 }; /* 128 bytes + ring size */
75 * Plugging is meant to work with larger batches of IOs. If we don't
76 * have more than the below, then don't bother setting up a plug.
78 #define AIO_PLUG_THRESHOLD 2
80 #define AIO_RING_PAGES 8
85 struct kioctx __rcu *table[];
89 unsigned reqs_available;
93 struct completion comp;
98 struct percpu_ref users;
101 struct percpu_ref reqs;
103 unsigned long user_id;
105 struct __percpu kioctx_cpu *cpu;
108 * For percpu reqs_available, number of slots we move to/from global
113 * This is what userspace passed to io_setup(), it's not used for
114 * anything but counting against the global max_reqs quota.
116 * The real limit is nr_events - 1, which will be larger (see
121 /* Size of ringbuffer, in units of struct io_event */
124 unsigned long mmap_base;
125 unsigned long mmap_size;
127 struct page **ring_pages;
130 struct rcu_work free_rwork; /* see free_ioctx() */
133 * signals when all in-flight requests are done
135 struct ctx_rq_wait *rq_wait;
139 * This counts the number of available slots in the ringbuffer,
140 * so we avoid overflowing it: it's decremented (if positive)
141 * when allocating a kiocb and incremented when the resulting
142 * io_event is pulled off the ringbuffer.
144 * We batch accesses to it with a percpu version.
146 atomic_t reqs_available;
147 } ____cacheline_aligned_in_smp;
151 struct list_head active_reqs; /* used for cancellation */
152 } ____cacheline_aligned_in_smp;
155 struct mutex ring_lock;
156 wait_queue_head_t wait;
157 } ____cacheline_aligned_in_smp;
161 unsigned completed_events;
162 spinlock_t completion_lock;
163 } ____cacheline_aligned_in_smp;
165 struct page *internal_pages[AIO_RING_PAGES];
166 struct file *aio_ring_file;
172 * First field must be the file pointer in all the
173 * iocb unions! See also 'struct kiocb' in <linux/fs.h>
177 struct work_struct work;
183 struct wait_queue_head *head;
187 struct wait_queue_entry wait;
188 struct work_struct work;
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.
199 struct file *ki_filp;
201 struct fsync_iocb fsync;
202 struct poll_iocb poll;
205 struct kioctx *ki_ctx;
206 kiocb_cancel_fn *ki_cancel;
208 struct io_event ki_res;
210 struct list_head ki_list; /* the aio core uses this
211 * for cancellation */
212 refcount_t ki_refcnt;
215 * If the aio_resfd field of the userspace iocb is not zero,
216 * this is the underlying eventfd context to deliver events to.
218 struct eventfd_ctx *ki_eventfd;
221 /*------ sysctl variables----*/
222 static DEFINE_SPINLOCK(aio_nr_lock);
223 unsigned long aio_nr; /* current system wide number of aio requests */
224 unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
225 /*----end sysctl variables---*/
227 static struct kmem_cache *kiocb_cachep;
228 static struct kmem_cache *kioctx_cachep;
230 static struct vfsmount *aio_mnt;
232 static const struct file_operations aio_ring_fops;
233 static const struct address_space_operations aio_ctx_aops;
235 static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
238 struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
240 return ERR_CAST(inode);
242 inode->i_mapping->a_ops = &aio_ctx_aops;
243 inode->i_mapping->private_data = ctx;
244 inode->i_size = PAGE_SIZE * nr_pages;
246 file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
247 O_RDWR, &aio_ring_fops);
253 static int aio_init_fs_context(struct fs_context *fc)
255 if (!init_pseudo(fc, AIO_RING_MAGIC))
257 fc->s_iflags |= SB_I_NOEXEC;
262 * Creates the slab caches used by the aio routines, panic on
263 * failure as this is done early during the boot sequence.
265 static int __init aio_setup(void)
267 static struct file_system_type aio_fs = {
269 .init_fs_context = aio_init_fs_context,
270 .kill_sb = kill_anon_super,
272 aio_mnt = kern_mount(&aio_fs);
274 panic("Failed to create aio fs mount.");
276 kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
277 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
280 __initcall(aio_setup);
282 static void put_aio_ring_file(struct kioctx *ctx)
284 struct file *aio_ring_file = ctx->aio_ring_file;
285 struct address_space *i_mapping;
288 truncate_setsize(file_inode(aio_ring_file), 0);
290 /* Prevent further access to the kioctx from migratepages */
291 i_mapping = aio_ring_file->f_mapping;
292 spin_lock(&i_mapping->private_lock);
293 i_mapping->private_data = NULL;
294 ctx->aio_ring_file = NULL;
295 spin_unlock(&i_mapping->private_lock);
301 static void aio_free_ring(struct kioctx *ctx)
305 /* Disconnect the kiotx from the ring file. This prevents future
306 * accesses to the kioctx from page migration.
308 put_aio_ring_file(ctx);
310 for (i = 0; i < ctx->nr_pages; i++) {
312 pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
313 page_count(ctx->ring_pages[i]));
314 page = ctx->ring_pages[i];
317 ctx->ring_pages[i] = NULL;
321 if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
322 kfree(ctx->ring_pages);
323 ctx->ring_pages = NULL;
327 static int aio_ring_mremap(struct vm_area_struct *vma)
329 struct file *file = vma->vm_file;
330 struct mm_struct *mm = vma->vm_mm;
331 struct kioctx_table *table;
332 int i, res = -EINVAL;
334 spin_lock(&mm->ioctx_lock);
336 table = rcu_dereference(mm->ioctx_table);
337 for (i = 0; i < table->nr; i++) {
340 ctx = rcu_dereference(table->table[i]);
341 if (ctx && ctx->aio_ring_file == file) {
342 if (!atomic_read(&ctx->dead)) {
343 ctx->user_id = ctx->mmap_base = vma->vm_start;
351 spin_unlock(&mm->ioctx_lock);
355 static const struct vm_operations_struct aio_ring_vm_ops = {
356 .mremap = aio_ring_mremap,
357 #if IS_ENABLED(CONFIG_MMU)
358 .fault = filemap_fault,
359 .map_pages = filemap_map_pages,
360 .page_mkwrite = filemap_page_mkwrite,
364 static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
366 vma->vm_flags |= VM_DONTEXPAND;
367 vma->vm_ops = &aio_ring_vm_ops;
371 static const struct file_operations aio_ring_fops = {
372 .mmap = aio_ring_mmap,
375 #if IS_ENABLED(CONFIG_MIGRATION)
376 static int aio_migratepage(struct address_space *mapping, struct page *new,
377 struct page *old, enum migrate_mode mode)
385 * We cannot support the _NO_COPY case here, because copy needs to
386 * happen under the ctx->completion_lock. That does not work with the
387 * migration workflow of MIGRATE_SYNC_NO_COPY.
389 if (mode == MIGRATE_SYNC_NO_COPY)
394 /* mapping->private_lock here protects against the kioctx teardown. */
395 spin_lock(&mapping->private_lock);
396 ctx = mapping->private_data;
402 /* The ring_lock mutex. The prevents aio_read_events() from writing
403 * to the ring's head, and prevents page migration from mucking in
404 * a partially initialized kiotx.
406 if (!mutex_trylock(&ctx->ring_lock)) {
412 if (idx < (pgoff_t)ctx->nr_pages) {
413 /* Make sure the old page hasn't already been changed */
414 if (ctx->ring_pages[idx] != old)
422 /* Writeback must be complete */
423 BUG_ON(PageWriteback(old));
426 rc = migrate_page_move_mapping(mapping, new, old, 1);
427 if (rc != MIGRATEPAGE_SUCCESS) {
432 /* Take completion_lock to prevent other writes to the ring buffer
433 * while the old page is copied to the new. This prevents new
434 * events from being lost.
436 spin_lock_irqsave(&ctx->completion_lock, flags);
437 migrate_page_copy(new, old);
438 BUG_ON(ctx->ring_pages[idx] != old);
439 ctx->ring_pages[idx] = new;
440 spin_unlock_irqrestore(&ctx->completion_lock, flags);
442 /* The old page is no longer accessible. */
446 mutex_unlock(&ctx->ring_lock);
448 spin_unlock(&mapping->private_lock);
453 static const struct address_space_operations aio_ctx_aops = {
454 .set_page_dirty = __set_page_dirty_no_writeback,
455 #if IS_ENABLED(CONFIG_MIGRATION)
456 .migratepage = aio_migratepage,
460 static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
462 struct aio_ring *ring;
463 struct mm_struct *mm = current->mm;
464 unsigned long size, unused;
469 /* Compensate for the ring buffer's head/tail overlap entry */
470 nr_events += 2; /* 1 is required, 2 for good luck */
472 size = sizeof(struct aio_ring);
473 size += sizeof(struct io_event) * nr_events;
475 nr_pages = PFN_UP(size);
479 file = aio_private_file(ctx, nr_pages);
481 ctx->aio_ring_file = NULL;
485 ctx->aio_ring_file = file;
486 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
487 / sizeof(struct io_event);
489 ctx->ring_pages = ctx->internal_pages;
490 if (nr_pages > AIO_RING_PAGES) {
491 ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
493 if (!ctx->ring_pages) {
494 put_aio_ring_file(ctx);
499 for (i = 0; i < nr_pages; i++) {
501 page = find_or_create_page(file->f_mapping,
502 i, GFP_HIGHUSER | __GFP_ZERO);
505 pr_debug("pid(%d) page[%d]->count=%d\n",
506 current->pid, i, page_count(page));
507 SetPageUptodate(page);
510 ctx->ring_pages[i] = page;
514 if (unlikely(i != nr_pages)) {
519 ctx->mmap_size = nr_pages * PAGE_SIZE;
520 pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
522 if (down_write_killable(&mm->mmap_sem)) {
528 ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
529 PROT_READ | PROT_WRITE,
530 MAP_SHARED, 0, &unused, NULL);
531 up_write(&mm->mmap_sem);
532 if (IS_ERR((void *)ctx->mmap_base)) {
538 pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
540 ctx->user_id = ctx->mmap_base;
541 ctx->nr_events = nr_events; /* trusted copy */
543 ring = kmap_atomic(ctx->ring_pages[0]);
544 ring->nr = nr_events; /* user copy */
546 ring->head = ring->tail = 0;
547 ring->magic = AIO_RING_MAGIC;
548 ring->compat_features = AIO_RING_COMPAT_FEATURES;
549 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
550 ring->header_length = sizeof(struct aio_ring);
552 flush_dcache_page(ctx->ring_pages[0]);
557 #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
558 #define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
559 #define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
561 void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
563 struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
564 struct kioctx *ctx = req->ki_ctx;
567 if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
570 spin_lock_irqsave(&ctx->ctx_lock, flags);
571 list_add_tail(&req->ki_list, &ctx->active_reqs);
572 req->ki_cancel = cancel;
573 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
575 EXPORT_SYMBOL(kiocb_set_cancel_fn);
578 * free_ioctx() should be RCU delayed to synchronize against the RCU
579 * protected lookup_ioctx() and also needs process context to call
580 * aio_free_ring(). Use rcu_work.
582 static void free_ioctx(struct work_struct *work)
584 struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
586 pr_debug("freeing %p\n", ctx);
589 free_percpu(ctx->cpu);
590 percpu_ref_exit(&ctx->reqs);
591 percpu_ref_exit(&ctx->users);
592 kmem_cache_free(kioctx_cachep, ctx);
595 static void free_ioctx_reqs(struct percpu_ref *ref)
597 struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
599 /* At this point we know that there are no any in-flight requests */
600 if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
601 complete(&ctx->rq_wait->comp);
603 /* Synchronize against RCU protected table->table[] dereferences */
604 INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
605 queue_rcu_work(system_wq, &ctx->free_rwork);
609 * When this function runs, the kioctx has been removed from the "hash table"
610 * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
611 * now it's safe to cancel any that need to be.
613 static void free_ioctx_users(struct percpu_ref *ref)
615 struct kioctx *ctx = container_of(ref, struct kioctx, users);
616 struct aio_kiocb *req;
618 spin_lock_irq(&ctx->ctx_lock);
620 while (!list_empty(&ctx->active_reqs)) {
621 req = list_first_entry(&ctx->active_reqs,
622 struct aio_kiocb, ki_list);
623 req->ki_cancel(&req->rw);
624 list_del_init(&req->ki_list);
627 spin_unlock_irq(&ctx->ctx_lock);
629 percpu_ref_kill(&ctx->reqs);
630 percpu_ref_put(&ctx->reqs);
633 static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
636 struct kioctx_table *table, *old;
637 struct aio_ring *ring;
639 spin_lock(&mm->ioctx_lock);
640 table = rcu_dereference_raw(mm->ioctx_table);
644 for (i = 0; i < table->nr; i++)
645 if (!rcu_access_pointer(table->table[i])) {
647 rcu_assign_pointer(table->table[i], ctx);
648 spin_unlock(&mm->ioctx_lock);
650 /* While kioctx setup is in progress,
651 * we are protected from page migration
652 * changes ring_pages by ->ring_lock.
654 ring = kmap_atomic(ctx->ring_pages[0]);
660 new_nr = (table ? table->nr : 1) * 4;
661 spin_unlock(&mm->ioctx_lock);
663 table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
670 spin_lock(&mm->ioctx_lock);
671 old = rcu_dereference_raw(mm->ioctx_table);
674 rcu_assign_pointer(mm->ioctx_table, table);
675 } else if (table->nr > old->nr) {
676 memcpy(table->table, old->table,
677 old->nr * sizeof(struct kioctx *));
679 rcu_assign_pointer(mm->ioctx_table, table);
688 static void aio_nr_sub(unsigned nr)
690 spin_lock(&aio_nr_lock);
691 if (WARN_ON(aio_nr - nr > aio_nr))
695 spin_unlock(&aio_nr_lock);
699 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
701 static struct kioctx *ioctx_alloc(unsigned nr_events)
703 struct mm_struct *mm = current->mm;
708 * Store the original nr_events -- what userspace passed to io_setup(),
709 * for counting against the global limit -- before it changes.
711 unsigned int max_reqs = nr_events;
714 * We keep track of the number of available ringbuffer slots, to prevent
715 * overflow (reqs_available), and we also use percpu counters for this.
717 * So since up to half the slots might be on other cpu's percpu counters
718 * and unavailable, double nr_events so userspace sees what they
719 * expected: additionally, we move req_batch slots to/from percpu
720 * counters at a time, so make sure that isn't 0:
722 nr_events = max(nr_events, num_possible_cpus() * 4);
725 /* Prevent overflows */
726 if (nr_events > (0x10000000U / sizeof(struct io_event))) {
727 pr_debug("ENOMEM: nr_events too high\n");
728 return ERR_PTR(-EINVAL);
731 if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
732 return ERR_PTR(-EAGAIN);
734 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
736 return ERR_PTR(-ENOMEM);
738 ctx->max_reqs = max_reqs;
740 spin_lock_init(&ctx->ctx_lock);
741 spin_lock_init(&ctx->completion_lock);
742 mutex_init(&ctx->ring_lock);
743 /* Protect against page migration throughout kiotx setup by keeping
744 * the ring_lock mutex held until setup is complete. */
745 mutex_lock(&ctx->ring_lock);
746 init_waitqueue_head(&ctx->wait);
748 INIT_LIST_HEAD(&ctx->active_reqs);
750 if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
753 if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
756 ctx->cpu = alloc_percpu(struct kioctx_cpu);
760 err = aio_setup_ring(ctx, nr_events);
764 atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
765 ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
766 if (ctx->req_batch < 1)
769 /* limit the number of system wide aios */
770 spin_lock(&aio_nr_lock);
771 if (aio_nr + ctx->max_reqs > aio_max_nr ||
772 aio_nr + ctx->max_reqs < aio_nr) {
773 spin_unlock(&aio_nr_lock);
777 aio_nr += ctx->max_reqs;
778 spin_unlock(&aio_nr_lock);
780 percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
781 percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
783 err = ioctx_add_table(ctx, mm);
787 /* Release the ring_lock mutex now that all setup is complete. */
788 mutex_unlock(&ctx->ring_lock);
790 pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
791 ctx, ctx->user_id, mm, ctx->nr_events);
795 aio_nr_sub(ctx->max_reqs);
797 atomic_set(&ctx->dead, 1);
799 vm_munmap(ctx->mmap_base, ctx->mmap_size);
802 mutex_unlock(&ctx->ring_lock);
803 free_percpu(ctx->cpu);
804 percpu_ref_exit(&ctx->reqs);
805 percpu_ref_exit(&ctx->users);
806 kmem_cache_free(kioctx_cachep, ctx);
807 pr_debug("error allocating ioctx %d\n", err);
812 * Cancels all outstanding aio requests on an aio context. Used
813 * when the processes owning a context have all exited to encourage
814 * the rapid destruction of the kioctx.
816 static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
817 struct ctx_rq_wait *wait)
819 struct kioctx_table *table;
821 spin_lock(&mm->ioctx_lock);
822 if (atomic_xchg(&ctx->dead, 1)) {
823 spin_unlock(&mm->ioctx_lock);
827 table = rcu_dereference_raw(mm->ioctx_table);
828 WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
829 RCU_INIT_POINTER(table->table[ctx->id], NULL);
830 spin_unlock(&mm->ioctx_lock);
832 /* free_ioctx_reqs() will do the necessary RCU synchronization */
833 wake_up_all(&ctx->wait);
836 * It'd be more correct to do this in free_ioctx(), after all
837 * the outstanding kiocbs have finished - but by then io_destroy
838 * has already returned, so io_setup() could potentially return
839 * -EAGAIN with no ioctxs actually in use (as far as userspace
842 aio_nr_sub(ctx->max_reqs);
845 vm_munmap(ctx->mmap_base, ctx->mmap_size);
848 percpu_ref_kill(&ctx->users);
853 * exit_aio: called when the last user of mm goes away. At this point, there is
854 * no way for any new requests to be submited or any of the io_* syscalls to be
855 * called on the context.
857 * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
860 void exit_aio(struct mm_struct *mm)
862 struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
863 struct ctx_rq_wait wait;
869 atomic_set(&wait.count, table->nr);
870 init_completion(&wait.comp);
873 for (i = 0; i < table->nr; ++i) {
875 rcu_dereference_protected(table->table[i], true);
883 * We don't need to bother with munmap() here - exit_mmap(mm)
884 * is coming and it'll unmap everything. And we simply can't,
885 * this is not necessarily our ->mm.
886 * Since kill_ioctx() uses non-zero ->mmap_size as indicator
887 * that it needs to unmap the area, just set it to 0.
890 kill_ioctx(mm, ctx, &wait);
893 if (!atomic_sub_and_test(skipped, &wait.count)) {
894 /* Wait until all IO for the context are done. */
895 wait_for_completion(&wait.comp);
898 RCU_INIT_POINTER(mm->ioctx_table, NULL);
902 static void put_reqs_available(struct kioctx *ctx, unsigned nr)
904 struct kioctx_cpu *kcpu;
907 local_irq_save(flags);
908 kcpu = this_cpu_ptr(ctx->cpu);
909 kcpu->reqs_available += nr;
911 while (kcpu->reqs_available >= ctx->req_batch * 2) {
912 kcpu->reqs_available -= ctx->req_batch;
913 atomic_add(ctx->req_batch, &ctx->reqs_available);
916 local_irq_restore(flags);
919 static bool __get_reqs_available(struct kioctx *ctx)
921 struct kioctx_cpu *kcpu;
925 local_irq_save(flags);
926 kcpu = this_cpu_ptr(ctx->cpu);
927 if (!kcpu->reqs_available) {
928 int old, avail = atomic_read(&ctx->reqs_available);
931 if (avail < ctx->req_batch)
935 avail = atomic_cmpxchg(&ctx->reqs_available,
936 avail, avail - ctx->req_batch);
937 } while (avail != old);
939 kcpu->reqs_available += ctx->req_batch;
943 kcpu->reqs_available--;
945 local_irq_restore(flags);
949 /* refill_reqs_available
950 * Updates the reqs_available reference counts used for tracking the
951 * number of free slots in the completion ring. This can be called
952 * from aio_complete() (to optimistically update reqs_available) or
953 * from aio_get_req() (the we're out of events case). It must be
954 * called holding ctx->completion_lock.
956 static void refill_reqs_available(struct kioctx *ctx, unsigned head,
959 unsigned events_in_ring, completed;
961 /* Clamp head since userland can write to it. */
962 head %= ctx->nr_events;
964 events_in_ring = tail - head;
966 events_in_ring = ctx->nr_events - (head - tail);
968 completed = ctx->completed_events;
969 if (events_in_ring < completed)
970 completed -= events_in_ring;
977 ctx->completed_events -= completed;
978 put_reqs_available(ctx, completed);
981 /* user_refill_reqs_available
982 * Called to refill reqs_available when aio_get_req() encounters an
983 * out of space in the completion ring.
985 static void user_refill_reqs_available(struct kioctx *ctx)
987 spin_lock_irq(&ctx->completion_lock);
988 if (ctx->completed_events) {
989 struct aio_ring *ring;
992 /* Access of ring->head may race with aio_read_events_ring()
993 * here, but that's okay since whether we read the old version
994 * or the new version, and either will be valid. The important
995 * part is that head cannot pass tail since we prevent
996 * aio_complete() from updating tail by holding
997 * ctx->completion_lock. Even if head is invalid, the check
998 * against ctx->completed_events below will make sure we do the
1001 ring = kmap_atomic(ctx->ring_pages[0]);
1003 kunmap_atomic(ring);
1005 refill_reqs_available(ctx, head, ctx->tail);
1008 spin_unlock_irq(&ctx->completion_lock);
1011 static bool get_reqs_available(struct kioctx *ctx)
1013 if (__get_reqs_available(ctx))
1015 user_refill_reqs_available(ctx);
1016 return __get_reqs_available(ctx);
1020 * Allocate a slot for an aio request.
1021 * Returns NULL if no requests are free.
1023 * The refcount is initialized to 2 - one for the async op completion,
1024 * one for the synchronous code that does this.
1026 static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
1028 struct aio_kiocb *req;
1030 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
1034 if (unlikely(!get_reqs_available(ctx))) {
1035 kmem_cache_free(kiocb_cachep, req);
1039 percpu_ref_get(&ctx->reqs);
1041 INIT_LIST_HEAD(&req->ki_list);
1042 refcount_set(&req->ki_refcnt, 2);
1043 req->ki_eventfd = NULL;
1047 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
1049 struct aio_ring __user *ring = (void __user *)ctx_id;
1050 struct mm_struct *mm = current->mm;
1051 struct kioctx *ctx, *ret = NULL;
1052 struct kioctx_table *table;
1055 if (get_user(id, &ring->id))
1059 table = rcu_dereference(mm->ioctx_table);
1061 if (!table || id >= table->nr)
1064 id = array_index_nospec(id, table->nr);
1065 ctx = rcu_dereference(table->table[id]);
1066 if (ctx && ctx->user_id == ctx_id) {
1067 if (percpu_ref_tryget_live(&ctx->users))
1075 static inline void iocb_destroy(struct aio_kiocb *iocb)
1077 if (iocb->ki_eventfd)
1078 eventfd_ctx_put(iocb->ki_eventfd);
1080 fput(iocb->ki_filp);
1081 percpu_ref_put(&iocb->ki_ctx->reqs);
1082 kmem_cache_free(kiocb_cachep, iocb);
1086 * Called when the io request on the given iocb is complete.
1088 static void aio_complete(struct aio_kiocb *iocb)
1090 struct kioctx *ctx = iocb->ki_ctx;
1091 struct aio_ring *ring;
1092 struct io_event *ev_page, *event;
1093 unsigned tail, pos, head;
1094 unsigned long flags;
1097 * Add a completion event to the ring buffer. Must be done holding
1098 * ctx->completion_lock to prevent other code from messing with the tail
1099 * pointer since we might be called from irq context.
1101 spin_lock_irqsave(&ctx->completion_lock, flags);
1104 pos = tail + AIO_EVENTS_OFFSET;
1106 if (++tail >= ctx->nr_events)
1109 ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1110 event = ev_page + pos % AIO_EVENTS_PER_PAGE;
1112 *event = iocb->ki_res;
1114 kunmap_atomic(ev_page);
1115 flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
1117 pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
1118 (void __user *)(unsigned long)iocb->ki_res.obj,
1119 iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
1121 /* after flagging the request as done, we
1122 * must never even look at it again
1124 smp_wmb(); /* make event visible before updating tail */
1128 ring = kmap_atomic(ctx->ring_pages[0]);
1131 kunmap_atomic(ring);
1132 flush_dcache_page(ctx->ring_pages[0]);
1134 ctx->completed_events++;
1135 if (ctx->completed_events > 1)
1136 refill_reqs_available(ctx, head, tail);
1137 spin_unlock_irqrestore(&ctx->completion_lock, flags);
1139 pr_debug("added to ring %p at [%u]\n", iocb, tail);
1142 * Check if the user asked us to deliver the result through an
1143 * eventfd. The eventfd_signal() function is safe to be called
1146 if (iocb->ki_eventfd)
1147 eventfd_signal(iocb->ki_eventfd, 1);
1150 * We have to order our ring_info tail store above and test
1151 * of the wait list below outside the wait lock. This is
1152 * like in wake_up_bit() where clearing a bit has to be
1153 * ordered with the unlocked test.
1157 if (waitqueue_active(&ctx->wait))
1158 wake_up(&ctx->wait);
1161 static inline void iocb_put(struct aio_kiocb *iocb)
1163 if (refcount_dec_and_test(&iocb->ki_refcnt)) {
1169 /* aio_read_events_ring
1170 * Pull an event off of the ioctx's event ring. Returns the number of
1173 static long aio_read_events_ring(struct kioctx *ctx,
1174 struct io_event __user *event, long nr)
1176 struct aio_ring *ring;
1177 unsigned head, tail, pos;
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.
1187 sched_annotate_sleep();
1188 mutex_lock(&ctx->ring_lock);
1190 /* Access to ->ring_pages here is protected by ctx->ring_lock. */
1191 ring = kmap_atomic(ctx->ring_pages[0]);
1194 kunmap_atomic(ring);
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.
1202 pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
1207 head %= ctx->nr_events;
1208 tail %= ctx->nr_events;
1212 struct io_event *ev;
1215 avail = (head <= tail ? tail : ctx->nr_events) - head;
1219 pos = head + AIO_EVENTS_OFFSET;
1220 page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
1221 pos %= AIO_EVENTS_PER_PAGE;
1223 avail = min(avail, nr - ret);
1224 avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
1227 copy_ret = copy_to_user(event + ret, ev + pos,
1228 sizeof(*ev) * avail);
1231 if (unlikely(copy_ret)) {
1238 head %= ctx->nr_events;
1241 ring = kmap_atomic(ctx->ring_pages[0]);
1243 kunmap_atomic(ring);
1244 flush_dcache_page(ctx->ring_pages[0]);
1246 pr_debug("%li h%u t%u\n", ret, head, tail);
1248 mutex_unlock(&ctx->ring_lock);
1253 static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
1254 struct io_event __user *event, long *i)
1256 long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
1261 if (unlikely(atomic_read(&ctx->dead)))
1267 return ret < 0 || *i >= min_nr;
1270 static long read_events(struct kioctx *ctx, long min_nr, long nr,
1271 struct io_event __user *event,
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.
1281 * But aio_read_events() can block, and if it blocks it's going to flip
1282 * the task state back to TASK_RUNNING.
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.
1291 aio_read_events(ctx, min_nr, nr, event, &ret);
1293 wait_event_interruptible_hrtimeout(ctx->wait,
1294 aio_read_events(ctx, min_nr, nr, event, &ret),
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
1312 SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
1314 struct kioctx *ioctx = NULL;
1318 ret = get_user(ctx, ctxp);
1323 if (unlikely(ctx || nr_events == 0)) {
1324 pr_debug("EINVAL: ctx %lu nr_events %u\n",
1329 ioctx = ioctx_alloc(nr_events);
1330 ret = PTR_ERR(ioctx);
1331 if (!IS_ERR(ioctx)) {
1332 ret = put_user(ioctx->user_id, ctxp);
1334 kill_ioctx(current->mm, ioctx, NULL);
1335 percpu_ref_put(&ioctx->users);
1342 #ifdef CONFIG_COMPAT
1343 COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
1345 struct kioctx *ioctx = NULL;
1349 ret = get_user(ctx, ctx32p);
1354 if (unlikely(ctx || nr_events == 0)) {
1355 pr_debug("EINVAL: ctx %lu nr_events %u\n",
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);
1366 kill_ioctx(current->mm, ioctx, NULL);
1367 percpu_ref_put(&ioctx->users);
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
1381 SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
1383 struct kioctx *ioctx = lookup_ioctx(ctx);
1384 if (likely(NULL != ioctx)) {
1385 struct ctx_rq_wait wait;
1388 init_completion(&wait.comp);
1389 atomic_set(&wait.count, 1);
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.
1395 ret = kill_ioctx(current->mm, ioctx, &wait);
1396 percpu_ref_put(&ioctx->users);
1398 /* Wait until all IO for the context are done. Otherwise kernel
1399 * keep using user-space buffers even if user thinks the context
1403 wait_for_completion(&wait.comp);
1407 pr_debug("EINVAL: invalid context id\n");
1411 static void aio_remove_iocb(struct aio_kiocb *iocb)
1413 struct kioctx *ctx = iocb->ki_ctx;
1414 unsigned long flags;
1416 spin_lock_irqsave(&ctx->ctx_lock, flags);
1417 list_del(&iocb->ki_list);
1418 spin_unlock_irqrestore(&ctx->ctx_lock, flags);
1421 static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
1423 struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
1425 if (!list_empty_careful(&iocb->ki_list))
1426 aio_remove_iocb(iocb);
1428 if (kiocb->ki_flags & IOCB_WRITE) {
1429 struct inode *inode = file_inode(kiocb->ki_filp);
1432 * Tell lockdep we inherited freeze protection from submission
1435 if (S_ISREG(inode->i_mode))
1436 __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
1437 file_end_write(kiocb->ki_filp);
1440 iocb->ki_res.res = res;
1441 iocb->ki_res.res2 = res2;
1445 static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
1449 req->ki_complete = aio_complete_rw;
1450 req->private = NULL;
1451 req->ki_pos = iocb->aio_offset;
1452 req->ki_flags = iocb_flags(req->ki_filp);
1453 if (iocb->aio_flags & IOCB_FLAG_RESFD)
1454 req->ki_flags |= IOCB_EVENTFD;
1455 req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp));
1456 if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
1458 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
1459 * aio_reqprio is interpreted as an I/O scheduling
1460 * class and priority.
1462 ret = ioprio_check_cap(iocb->aio_reqprio);
1464 pr_debug("aio ioprio check cap error: %d\n", ret);
1468 req->ki_ioprio = iocb->aio_reqprio;
1470 req->ki_ioprio = get_current_ioprio();
1472 ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
1476 req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
1480 static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
1481 struct iovec **iovec, bool vectored, bool compat,
1482 struct iov_iter *iter)
1484 void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
1485 size_t len = iocb->aio_nbytes;
1488 ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
1492 #ifdef CONFIG_COMPAT
1494 return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec,
1497 return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter);
1500 static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
1506 case -ERESTARTNOINTR:
1507 case -ERESTARTNOHAND:
1508 case -ERESTART_RESTARTBLOCK:
1510 * There's no easy way to restart the syscall since other AIO's
1511 * may be already running. Just fail this IO with EINTR.
1516 req->ki_complete(req, ret, 0);
1520 static int aio_read(struct kiocb *req, const struct iocb *iocb,
1521 bool vectored, bool compat)
1523 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1524 struct iov_iter iter;
1528 ret = aio_prep_rw(req, iocb);
1531 file = req->ki_filp;
1532 if (unlikely(!(file->f_mode & FMODE_READ)))
1535 if (unlikely(!file->f_op->read_iter))
1538 ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
1541 ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
1543 aio_rw_done(req, call_read_iter(file, req, &iter));
1548 static int aio_write(struct kiocb *req, const struct iocb *iocb,
1549 bool vectored, bool compat)
1551 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
1552 struct iov_iter iter;
1556 ret = aio_prep_rw(req, iocb);
1559 file = req->ki_filp;
1561 if (unlikely(!(file->f_mode & FMODE_WRITE)))
1563 if (unlikely(!file->f_op->write_iter))
1566 ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
1569 ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
1572 * Open-code file_start_write here to grab freeze protection,
1573 * which will be released by another thread in
1574 * aio_complete_rw(). Fool lockdep by telling it the lock got
1575 * released so that it doesn't complain about the held lock when
1576 * we return to userspace.
1578 if (S_ISREG(file_inode(file)->i_mode)) {
1579 __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
1580 __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
1582 req->ki_flags |= IOCB_WRITE;
1583 aio_rw_done(req, call_write_iter(file, req, &iter));
1589 static void aio_fsync_work(struct work_struct *work)
1591 struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
1593 iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
1597 static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
1600 if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
1601 iocb->aio_rw_flags))
1604 if (unlikely(!req->file->f_op->fsync))
1607 req->datasync = datasync;
1608 INIT_WORK(&req->work, aio_fsync_work);
1609 schedule_work(&req->work);
1613 static void aio_poll_complete_work(struct work_struct *work)
1615 struct poll_iocb *req = container_of(work, struct poll_iocb, work);
1616 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1617 struct poll_table_struct pt = { ._key = req->events };
1618 struct kioctx *ctx = iocb->ki_ctx;
1621 if (!READ_ONCE(req->cancelled))
1622 mask = vfs_poll(req->file, &pt) & req->events;
1625 * Note that ->ki_cancel callers also delete iocb from active_reqs after
1626 * calling ->ki_cancel. We need the ctx_lock roundtrip here to
1627 * synchronize with them. In the cancellation case the list_del_init
1628 * itself is not actually needed, but harmless so we keep it in to
1629 * avoid further branches in the fast path.
1631 spin_lock_irq(&ctx->ctx_lock);
1632 if (!mask && !READ_ONCE(req->cancelled)) {
1633 add_wait_queue(req->head, &req->wait);
1634 spin_unlock_irq(&ctx->ctx_lock);
1637 list_del_init(&iocb->ki_list);
1638 iocb->ki_res.res = mangle_poll(mask);
1640 spin_unlock_irq(&ctx->ctx_lock);
1645 /* assumes we are called with irqs disabled */
1646 static int aio_poll_cancel(struct kiocb *iocb)
1648 struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
1649 struct poll_iocb *req = &aiocb->poll;
1651 spin_lock(&req->head->lock);
1652 WRITE_ONCE(req->cancelled, true);
1653 if (!list_empty(&req->wait.entry)) {
1654 list_del_init(&req->wait.entry);
1655 schedule_work(&aiocb->poll.work);
1657 spin_unlock(&req->head->lock);
1662 static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
1665 struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
1666 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
1667 __poll_t mask = key_to_poll(key);
1668 unsigned long flags;
1670 /* for instances that support it check for an event match first: */
1671 if (mask && !(mask & req->events))
1674 list_del_init(&req->wait.entry);
1676 if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
1678 * Try to complete the iocb inline if we can. Use
1679 * irqsave/irqrestore because not all filesystems (e.g. fuse)
1680 * call this function with IRQs disabled and because IRQs
1681 * have to be disabled before ctx_lock is obtained.
1683 list_del(&iocb->ki_list);
1684 iocb->ki_res.res = mangle_poll(mask);
1686 spin_unlock_irqrestore(&iocb->ki_ctx->ctx_lock, flags);
1689 schedule_work(&req->work);
1694 struct aio_poll_table {
1695 struct poll_table_struct pt;
1696 struct aio_kiocb *iocb;
1701 aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
1702 struct poll_table_struct *p)
1704 struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
1706 /* multiple wait queues per file are not supported */
1707 if (unlikely(pt->iocb->poll.head)) {
1708 pt->error = -EINVAL;
1713 pt->iocb->poll.head = head;
1714 add_wait_queue(head, &pt->iocb->poll.wait);
1717 static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
1719 struct kioctx *ctx = aiocb->ki_ctx;
1720 struct poll_iocb *req = &aiocb->poll;
1721 struct aio_poll_table apt;
1722 bool cancel = false;
1725 /* reject any unknown events outside the normal event mask. */
1726 if ((u16)iocb->aio_buf != iocb->aio_buf)
1728 /* reject fields that are not defined for poll */
1729 if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
1732 INIT_WORK(&req->work, aio_poll_complete_work);
1733 req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
1737 req->cancelled = false;
1739 apt.pt._qproc = aio_poll_queue_proc;
1740 apt.pt._key = req->events;
1742 apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
1744 /* initialized the list so that we can do list_empty checks */
1745 INIT_LIST_HEAD(&req->wait.entry);
1746 init_waitqueue_func_entry(&req->wait, aio_poll_wake);
1748 mask = vfs_poll(req->file, &apt.pt) & req->events;
1749 spin_lock_irq(&ctx->ctx_lock);
1750 if (likely(req->head)) {
1751 spin_lock(&req->head->lock);
1752 if (unlikely(list_empty(&req->wait.entry))) {
1758 if (mask || apt.error) {
1759 list_del_init(&req->wait.entry);
1760 } else if (cancel) {
1761 WRITE_ONCE(req->cancelled, true);
1762 } else if (!req->done) { /* actually waiting for an event */
1763 list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
1764 aiocb->ki_cancel = aio_poll_cancel;
1766 spin_unlock(&req->head->lock);
1768 if (mask) { /* no async, we'd stolen it */
1769 aiocb->ki_res.res = mangle_poll(mask);
1772 spin_unlock_irq(&ctx->ctx_lock);
1778 static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
1779 struct iocb __user *user_iocb, struct aio_kiocb *req,
1782 req->ki_filp = fget(iocb->aio_fildes);
1783 if (unlikely(!req->ki_filp))
1786 if (iocb->aio_flags & IOCB_FLAG_RESFD) {
1787 struct eventfd_ctx *eventfd;
1789 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
1790 * instance of the file* now. The file descriptor must be
1791 * an eventfd() fd, and will be signaled for each completed
1792 * event using the eventfd_signal() function.
1794 eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
1795 if (IS_ERR(eventfd))
1796 return PTR_ERR(eventfd);
1798 req->ki_eventfd = eventfd;
1801 if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
1802 pr_debug("EFAULT: aio_key\n");
1806 req->ki_res.obj = (u64)(unsigned long)user_iocb;
1807 req->ki_res.data = iocb->aio_data;
1808 req->ki_res.res = 0;
1809 req->ki_res.res2 = 0;
1811 switch (iocb->aio_lio_opcode) {
1812 case IOCB_CMD_PREAD:
1813 return aio_read(&req->rw, iocb, false, compat);
1814 case IOCB_CMD_PWRITE:
1815 return aio_write(&req->rw, iocb, false, compat);
1816 case IOCB_CMD_PREADV:
1817 return aio_read(&req->rw, iocb, true, compat);
1818 case IOCB_CMD_PWRITEV:
1819 return aio_write(&req->rw, iocb, true, compat);
1820 case IOCB_CMD_FSYNC:
1821 return aio_fsync(&req->fsync, iocb, false);
1822 case IOCB_CMD_FDSYNC:
1823 return aio_fsync(&req->fsync, iocb, true);
1825 return aio_poll(req, iocb);
1827 pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
1832 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
1835 struct aio_kiocb *req;
1839 if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
1842 /* enforce forwards compatibility on users */
1843 if (unlikely(iocb.aio_reserved2)) {
1844 pr_debug("EINVAL: reserve field set\n");
1848 /* prevent overflows */
1850 (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
1851 (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
1852 ((ssize_t)iocb.aio_nbytes < 0)
1854 pr_debug("EINVAL: overflow check\n");
1858 req = aio_get_req(ctx);
1862 err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
1864 /* Done with the synchronous reference */
1868 * If err is 0, we'd either done aio_complete() ourselves or have
1869 * arranged for that to be done asynchronously. Anything non-zero
1870 * means that we need to destroy req ourselves.
1872 if (unlikely(err)) {
1874 put_reqs_available(ctx, 1);
1880 * Queue the nr iocbs pointed to by iocbpp for processing. Returns
1881 * the number of iocbs queued. May return -EINVAL if the aio_context
1882 * specified by ctx_id is invalid, if nr is < 0, if the iocb at
1883 * *iocbpp[0] is not properly initialized, if the operation specified
1884 * is invalid for the file descriptor in the iocb. May fail with
1885 * -EFAULT if any of the data structures point to invalid data. May
1886 * fail with -EBADF if the file descriptor specified in the first
1887 * iocb is invalid. May fail with -EAGAIN if insufficient resources
1888 * are available to queue any iocbs. Will return 0 if nr is 0. Will
1889 * fail with -ENOSYS if not implemented.
1891 SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
1892 struct iocb __user * __user *, iocbpp)
1897 struct blk_plug plug;
1899 if (unlikely(nr < 0))
1902 ctx = lookup_ioctx(ctx_id);
1903 if (unlikely(!ctx)) {
1904 pr_debug("EINVAL: invalid context id\n");
1908 if (nr > ctx->nr_events)
1909 nr = ctx->nr_events;
1911 if (nr > AIO_PLUG_THRESHOLD)
1912 blk_start_plug(&plug);
1913 for (i = 0; i < nr; i++) {
1914 struct iocb __user *user_iocb;
1916 if (unlikely(get_user(user_iocb, iocbpp + i))) {
1921 ret = io_submit_one(ctx, user_iocb, false);
1925 if (nr > AIO_PLUG_THRESHOLD)
1926 blk_finish_plug(&plug);
1928 percpu_ref_put(&ctx->users);
1932 #ifdef CONFIG_COMPAT
1933 COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
1934 int, nr, compat_uptr_t __user *, iocbpp)
1939 struct blk_plug plug;
1941 if (unlikely(nr < 0))
1944 ctx = lookup_ioctx(ctx_id);
1945 if (unlikely(!ctx)) {
1946 pr_debug("EINVAL: invalid context id\n");
1950 if (nr > ctx->nr_events)
1951 nr = ctx->nr_events;
1953 if (nr > AIO_PLUG_THRESHOLD)
1954 blk_start_plug(&plug);
1955 for (i = 0; i < nr; i++) {
1956 compat_uptr_t user_iocb;
1958 if (unlikely(get_user(user_iocb, iocbpp + i))) {
1963 ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
1967 if (nr > AIO_PLUG_THRESHOLD)
1968 blk_finish_plug(&plug);
1970 percpu_ref_put(&ctx->users);
1976 * Attempts to cancel an iocb previously passed to io_submit. If
1977 * the operation is successfully cancelled, the resulting event is
1978 * copied into the memory pointed to by result without being placed
1979 * into the completion queue and 0 is returned. May fail with
1980 * -EFAULT if any of the data structures pointed to are invalid.
1981 * May fail with -EINVAL if aio_context specified by ctx_id is
1982 * invalid. May fail with -EAGAIN if the iocb specified was not
1983 * cancelled. Will fail with -ENOSYS if not implemented.
1985 SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
1986 struct io_event __user *, result)
1989 struct aio_kiocb *kiocb;
1992 u64 obj = (u64)(unsigned long)iocb;
1994 if (unlikely(get_user(key, &iocb->aio_key)))
1996 if (unlikely(key != KIOCB_KEY))
1999 ctx = lookup_ioctx(ctx_id);
2003 spin_lock_irq(&ctx->ctx_lock);
2004 /* TODO: use a hash or array, this sucks. */
2005 list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
2006 if (kiocb->ki_res.obj == obj) {
2007 ret = kiocb->ki_cancel(&kiocb->rw);
2008 list_del_init(&kiocb->ki_list);
2012 spin_unlock_irq(&ctx->ctx_lock);
2016 * The result argument is no longer used - the io_event is
2017 * always delivered via the ring buffer. -EINPROGRESS indicates
2018 * cancellation is progress:
2023 percpu_ref_put(&ctx->users);
2028 static long do_io_getevents(aio_context_t ctx_id,
2031 struct io_event __user *events,
2032 struct timespec64 *ts)
2034 ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
2035 struct kioctx *ioctx = lookup_ioctx(ctx_id);
2038 if (likely(ioctx)) {
2039 if (likely(min_nr <= nr && min_nr >= 0))
2040 ret = read_events(ioctx, min_nr, nr, events, until);
2041 percpu_ref_put(&ioctx->users);
2048 * Attempts to read at least min_nr events and up to nr events from
2049 * the completion queue for the aio_context specified by ctx_id. If
2050 * it succeeds, the number of read events is returned. May fail with
2051 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
2052 * out of range, if timeout is out of range. May fail with -EFAULT
2053 * if any of the memory specified is invalid. May return 0 or
2054 * < min_nr if the timeout specified by timeout has elapsed
2055 * before sufficient events are available, where timeout == NULL
2056 * specifies an infinite timeout. Note that the timeout pointed to by
2057 * timeout is relative. Will fail with -ENOSYS if not implemented.
2061 SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
2064 struct io_event __user *, events,
2065 struct __kernel_timespec __user *, timeout)
2067 struct timespec64 ts;
2070 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2073 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2074 if (!ret && signal_pending(current))
2081 struct __aio_sigset {
2082 const sigset_t __user *sigmask;
2086 SYSCALL_DEFINE6(io_pgetevents,
2087 aio_context_t, ctx_id,
2090 struct io_event __user *, events,
2091 struct __kernel_timespec __user *, timeout,
2092 const struct __aio_sigset __user *, usig)
2094 struct __aio_sigset ksig = { NULL, };
2095 struct timespec64 ts;
2099 if (timeout && unlikely(get_timespec64(&ts, timeout)))
2102 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2105 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2109 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2111 interrupted = signal_pending(current);
2112 restore_saved_sigmask_unless(interrupted);
2113 if (interrupted && !ret)
2114 ret = -ERESTARTNOHAND;
2119 #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
2121 SYSCALL_DEFINE6(io_pgetevents_time32,
2122 aio_context_t, ctx_id,
2125 struct io_event __user *, events,
2126 struct old_timespec32 __user *, timeout,
2127 const struct __aio_sigset __user *, usig)
2129 struct __aio_sigset ksig = { NULL, };
2130 struct timespec64 ts;
2134 if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
2137 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2141 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
2145 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
2147 interrupted = signal_pending(current);
2148 restore_saved_sigmask_unless(interrupted);
2149 if (interrupted && !ret)
2150 ret = -ERESTARTNOHAND;
2157 #if defined(CONFIG_COMPAT_32BIT_TIME)
2159 SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
2162 struct io_event __user *, events,
2163 struct old_timespec32 __user *, timeout)
2165 struct timespec64 t;
2168 if (timeout && get_old_timespec32(&t, timeout))
2171 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2172 if (!ret && signal_pending(current))
2179 #ifdef CONFIG_COMPAT
2181 struct __compat_aio_sigset {
2182 compat_uptr_t sigmask;
2183 compat_size_t sigsetsize;
2186 #if defined(CONFIG_COMPAT_32BIT_TIME)
2188 COMPAT_SYSCALL_DEFINE6(io_pgetevents,
2189 compat_aio_context_t, ctx_id,
2190 compat_long_t, min_nr,
2192 struct io_event __user *, events,
2193 struct old_timespec32 __user *, timeout,
2194 const struct __compat_aio_sigset __user *, usig)
2196 struct __compat_aio_sigset ksig = { 0, };
2197 struct timespec64 t;
2201 if (timeout && get_old_timespec32(&t, timeout))
2204 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2207 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2211 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2213 interrupted = signal_pending(current);
2214 restore_saved_sigmask_unless(interrupted);
2215 if (interrupted && !ret)
2216 ret = -ERESTARTNOHAND;
2223 COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
2224 compat_aio_context_t, ctx_id,
2225 compat_long_t, min_nr,
2227 struct io_event __user *, events,
2228 struct __kernel_timespec __user *, timeout,
2229 const struct __compat_aio_sigset __user *, usig)
2231 struct __compat_aio_sigset ksig = { 0, };
2232 struct timespec64 t;
2236 if (timeout && get_timespec64(&t, timeout))
2239 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
2242 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
2246 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
2248 interrupted = signal_pending(current);
2249 restore_saved_sigmask_unless(interrupted);
2250 if (interrupted && !ret)
2251 ret = -ERESTARTNOHAND;