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1/*2 * An async IO implementation for Linux3 * Written by Benjamin LaHaise <bcrl@kvack.org>4 *5 * Implements an efficient asynchronous io interface.6 *7 * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.8 * Copyright 2018 Christoph Hellwig.9 *10 * See ../COPYING for licensing terms.11 */12#define pr_fmt(fmt) "%s: " fmt, __func__13 14#include <linux/kernel.h>15#include <linux/init.h>16#include <linux/errno.h>17#include <linux/time.h>18#include <linux/aio_abi.h>19#include <linux/export.h>20#include <linux/syscalls.h>21#include <linux/backing-dev.h>22#include <linux/refcount.h>23#include <linux/uio.h>24 25#include <linux/sched/signal.h>26#include <linux/fs.h>27#include <linux/file.h>28#include <linux/mm.h>29#include <linux/mman.h>30#include <linux/percpu.h>31#include <linux/slab.h>32#include <linux/timer.h>33#include <linux/aio.h>34#include <linux/highmem.h>35#include <linux/workqueue.h>36#include <linux/security.h>37#include <linux/eventfd.h>38#include <linux/blkdev.h>39#include <linux/compat.h>40#include <linux/migrate.h>41#include <linux/ramfs.h>42#include <linux/percpu-refcount.h>43#include <linux/mount.h>44#include <linux/pseudo_fs.h>45 46#include <linux/uaccess.h>47#include <linux/nospec.h>48 49#include "internal.h"50 51#define KIOCB_KEY 052 53#define AIO_RING_MAGIC 0xa10a10a154#define AIO_RING_COMPAT_FEATURES 155#define AIO_RING_INCOMPAT_FEATURES 056struct aio_ring {57 unsigned id; /* kernel internal index number */58 unsigned nr; /* number of io_events */59 unsigned head; /* Written to by userland or under ring_lock60 * mutex by aio_read_events_ring(). */61 unsigned tail;62 63 unsigned magic;64 unsigned compat_features;65 unsigned incompat_features;66 unsigned header_length; /* size of aio_ring */67 68 69 struct io_event io_events[];70}; /* 128 bytes + ring size */71 72/*73 * Plugging is meant to work with larger batches of IOs. If we don't74 * have more than the below, then don't bother setting up a plug.75 */76#define AIO_PLUG_THRESHOLD 277 78#define AIO_RING_PAGES 879 80struct kioctx_table {81 struct rcu_head rcu;82 unsigned nr;83 struct kioctx __rcu *table[] __counted_by(nr);84};85 86struct kioctx_cpu {87 unsigned reqs_available;88};89 90struct ctx_rq_wait {91 struct completion comp;92 atomic_t count;93};94 95struct kioctx {96 struct percpu_ref users;97 atomic_t dead;98 99 struct percpu_ref reqs;100 101 unsigned long user_id;102 103 struct kioctx_cpu __percpu *cpu;104 105 /*106 * For percpu reqs_available, number of slots we move to/from global107 * counter at a time:108 */109 unsigned req_batch;110 /*111 * This is what userspace passed to io_setup(), it's not used for112 * anything but counting against the global max_reqs quota.113 *114 * The real limit is nr_events - 1, which will be larger (see115 * aio_setup_ring())116 */117 unsigned max_reqs;118 119 /* Size of ringbuffer, in units of struct io_event */120 unsigned nr_events;121 122 unsigned long mmap_base;123 unsigned long mmap_size;124 125 struct folio **ring_folios;126 long nr_pages;127 128 struct rcu_work free_rwork; /* see free_ioctx() */129 130 /*131 * signals when all in-flight requests are done132 */133 struct ctx_rq_wait *rq_wait;134 135 struct {136 /*137 * This counts the number of available slots in the ringbuffer,138 * so we avoid overflowing it: it's decremented (if positive)139 * when allocating a kiocb and incremented when the resulting140 * io_event is pulled off the ringbuffer.141 *142 * We batch accesses to it with a percpu version.143 */144 atomic_t reqs_available;145 } ____cacheline_aligned_in_smp;146 147 struct {148 spinlock_t ctx_lock;149 struct list_head active_reqs; /* used for cancellation */150 } ____cacheline_aligned_in_smp;151 152 struct {153 struct mutex ring_lock;154 wait_queue_head_t wait;155 } ____cacheline_aligned_in_smp;156 157 struct {158 unsigned tail;159 unsigned completed_events;160 spinlock_t completion_lock;161 } ____cacheline_aligned_in_smp;162 163 struct folio *internal_folios[AIO_RING_PAGES];164 struct file *aio_ring_file;165 166 unsigned id;167};168 169/*170 * First field must be the file pointer in all the171 * iocb unions! See also 'struct kiocb' in <linux/fs.h>172 */173struct fsync_iocb {174 struct file *file;175 struct work_struct work;176 bool datasync;177 struct cred *creds;178};179 180struct poll_iocb {181 struct file *file;182 struct wait_queue_head *head;183 __poll_t events;184 bool cancelled;185 bool work_scheduled;186 bool work_need_resched;187 struct wait_queue_entry wait;188 struct work_struct work;189};190 191/*192 * NOTE! Each of the iocb union members has the file pointer193 * as the first entry in their struct definition. So you can194 * access the file pointer through any of the sub-structs,195 * or directly as just 'ki_filp' in this struct.196 */197struct aio_kiocb {198 union {199 struct file *ki_filp;200 struct kiocb rw;201 struct fsync_iocb fsync;202 struct poll_iocb poll;203 };204 205 struct kioctx *ki_ctx;206 kiocb_cancel_fn *ki_cancel;207 208 struct io_event ki_res;209 210 struct list_head ki_list; /* the aio core uses this211 * for cancellation */212 refcount_t ki_refcnt;213 214 /*215 * If the aio_resfd field of the userspace iocb is not zero,216 * this is the underlying eventfd context to deliver events to.217 */218 struct eventfd_ctx *ki_eventfd;219};220 221/*------ sysctl variables----*/222static DEFINE_SPINLOCK(aio_nr_lock);223static unsigned long aio_nr; /* current system wide number of aio requests */224static unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */225/*----end sysctl variables---*/226#ifdef CONFIG_SYSCTL227static struct ctl_table aio_sysctls[] = {228 {229 .procname = "aio-nr",230 .data = &aio_nr,231 .maxlen = sizeof(aio_nr),232 .mode = 0444,233 .proc_handler = proc_doulongvec_minmax,234 },235 {236 .procname = "aio-max-nr",237 .data = &aio_max_nr,238 .maxlen = sizeof(aio_max_nr),239 .mode = 0644,240 .proc_handler = proc_doulongvec_minmax,241 },242};243 244static void __init aio_sysctl_init(void)245{246 register_sysctl_init("fs", aio_sysctls);247}248#else249#define aio_sysctl_init() do { } while (0)250#endif251 252static struct kmem_cache *kiocb_cachep;253static struct kmem_cache *kioctx_cachep;254 255static struct vfsmount *aio_mnt;256 257static const struct file_operations aio_ring_fops;258static const struct address_space_operations aio_ctx_aops;259 260static HWJS_SUSPENDS struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)261{262 struct file *file;263 struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);264 if (IS_ERR(inode))265 return ERR_CAST(inode);266 267 inode->i_mapping->a_ops = &aio_ctx_aops;268 inode->i_mapping->i_private_data = ctx;269 inode->i_size = PAGE_SIZE * nr_pages;270 271 file = alloc_file_pseudo(inode, aio_mnt, "[aio]",272 O_RDWR, &aio_ring_fops);273 if (IS_ERR(file))274 iput(inode);275 return file;276}277 278static int aio_init_fs_context(struct fs_context *fc)279{280 if (!init_pseudo(fc, AIO_RING_MAGIC))281 return -ENOMEM;282 fc->s_iflags |= SB_I_NOEXEC;283 return 0;284}285 286/* aio_setup287 * Creates the slab caches used by the aio routines, panic on288 * failure as this is done early during the boot sequence.289 */290static int __init aio_setup(void)291{292 static struct file_system_type aio_fs = {293 .name = "aio",294 .init_fs_context = aio_init_fs_context,295 .kill_sb = kill_anon_super,296 };297 aio_mnt = kern_mount(&aio_fs);298 if (IS_ERR(aio_mnt))299 panic("Failed to create aio fs mount.");300 301 kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);302 kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);303 aio_sysctl_init();304 return 0;305}306__initcall(aio_setup);307 308static HWJS_SUSPENDS void put_aio_ring_file(struct kioctx *ctx)309{310 struct file *aio_ring_file = ctx->aio_ring_file;311 struct address_space *i_mapping;312 313 if (aio_ring_file) {314 truncate_setsize(file_inode(aio_ring_file), 0);315 316 /* Prevent further access to the kioctx from migratepages */317 i_mapping = aio_ring_file->f_mapping;318 spin_lock(&i_mapping->i_private_lock);319 i_mapping->i_private_data = NULL;320 ctx->aio_ring_file = NULL;321 spin_unlock(&i_mapping->i_private_lock);322 323 fput(aio_ring_file);324 }325}326 327static HWJS_SUSPENDS void aio_free_ring(struct kioctx *ctx)328{329 int i;330 331 /* Disconnect the kiotx from the ring file. This prevents future332 * accesses to the kioctx from page migration.333 */334 put_aio_ring_file(ctx);335 336 for (i = 0; i < ctx->nr_pages; i++) {337 struct folio *folio = ctx->ring_folios[i];338 339 if (!folio)340 continue;341 342 pr_debug("pid(%d) [%d] folio->count=%d\n", current->pid, i,343 folio_ref_count(folio));344 ctx->ring_folios[i] = NULL;345 folio_put(folio);346 }347 348 if (ctx->ring_folios && ctx->ring_folios != ctx->internal_folios) {349 kfree(ctx->ring_folios);350 ctx->ring_folios = NULL;351 }352}353 354static int aio_ring_mremap(struct vm_area_struct *vma)355{356 struct file *file = vma->vm_file;357 struct mm_struct *mm = vma->vm_mm;358 struct kioctx_table *table;359 int i, res = -EINVAL;360 361 spin_lock(&mm->ioctx_lock);362 rcu_read_lock();363 table = rcu_dereference(mm->ioctx_table);364 if (!table)365 goto out_unlock;366 367 for (i = 0; i < table->nr; i++) {368 struct kioctx *ctx;369 370 ctx = rcu_dereference(table->table[i]);371 if (ctx && ctx->aio_ring_file == file) {372 if (!atomic_read(&ctx->dead)) {373 ctx->user_id = ctx->mmap_base = vma->vm_start;374 res = 0;375 }376 break;377 }378 }379 380out_unlock:381 rcu_read_unlock();382 spin_unlock(&mm->ioctx_lock);383 return res;384}385 386static const struct vm_operations_struct aio_ring_vm_ops = {387 .mremap = aio_ring_mremap,388#if IS_ENABLED(CONFIG_MMU)389 .fault = filemap_fault,390 .map_pages = filemap_map_pages,391 .page_mkwrite = filemap_page_mkwrite,392#endif393};394 395static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)396{397 vm_flags_set(vma, VM_DONTEXPAND);398 vma->vm_ops = &aio_ring_vm_ops;399 return 0;400}401 402static const struct file_operations aio_ring_fops = {403 .mmap = aio_ring_mmap,404};405 406#if IS_ENABLED(CONFIG_MIGRATION)407static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,408 struct folio *src, enum migrate_mode mode)409{410 struct kioctx *ctx;411 unsigned long flags;412 pgoff_t idx;413 int rc = 0;414 415 /* mapping->i_private_lock here protects against the kioctx teardown. */416 spin_lock(&mapping->i_private_lock);417 ctx = mapping->i_private_data;418 if (!ctx) {419 rc = -EINVAL;420 goto out;421 }422 423 /* The ring_lock mutex. The prevents aio_read_events() from writing424 * to the ring's head, and prevents page migration from mucking in425 * a partially initialized kiotx.426 */427 if (!mutex_trylock(&ctx->ring_lock)) {428 rc = -EAGAIN;429 goto out;430 }431 432 idx = src->index;433 if (idx < (pgoff_t)ctx->nr_pages) {434 /* Make sure the old folio hasn't already been changed */435 if (ctx->ring_folios[idx] != src)436 rc = -EAGAIN;437 } else438 rc = -EINVAL;439 440 if (rc != 0)441 goto out_unlock;442 443 /* Writeback must be complete */444 BUG_ON(folio_test_writeback(src));445 folio_get(dst);446 447 rc = folio_migrate_mapping(mapping, dst, src, 1);448 if (rc != MIGRATEPAGE_SUCCESS) {449 folio_put(dst);450 goto out_unlock;451 }452 453 /* Take completion_lock to prevent other writes to the ring buffer454 * while the old folio is copied to the new. This prevents new455 * events from being lost.456 */457 spin_lock_irqsave(&ctx->completion_lock, flags);458 folio_copy(dst, src);459 folio_migrate_flags(dst, src);460 BUG_ON(ctx->ring_folios[idx] != src);461 ctx->ring_folios[idx] = dst;462 spin_unlock_irqrestore(&ctx->completion_lock, flags);463 464 /* The old folio is no longer accessible. */465 folio_put(src);466 467out_unlock:468 mutex_unlock(&ctx->ring_lock);469out:470 spin_unlock(&mapping->i_private_lock);471 return rc;472}473#else474#define aio_migrate_folio NULL475#endif476 477static const struct address_space_operations aio_ctx_aops = {478 .dirty_folio = noop_dirty_folio,479 .migrate_folio = aio_migrate_folio,480};481 482static HWJS_SUSPENDS int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)483{484 struct aio_ring *ring;485 struct mm_struct *mm = current->mm;486 unsigned long size, unused;487 int nr_pages;488 int i;489 struct file *file;490 491 /* Compensate for the ring buffer's head/tail overlap entry */492 nr_events += 2; /* 1 is required, 2 for good luck */493 494 size = sizeof(struct aio_ring);495 size += sizeof(struct io_event) * nr_events;496 497 nr_pages = PFN_UP(size);498 if (nr_pages < 0)499 return -EINVAL;500 501 file = aio_private_file(ctx, nr_pages);502 if (IS_ERR(file)) {503 ctx->aio_ring_file = NULL;504 return -ENOMEM;505 }506 507 ctx->aio_ring_file = file;508 nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))509 / sizeof(struct io_event);510 511 ctx->ring_folios = ctx->internal_folios;512 if (nr_pages > AIO_RING_PAGES) {513 ctx->ring_folios = kcalloc(nr_pages, sizeof(struct folio *),514 GFP_KERNEL);515 if (!ctx->ring_folios) {516 put_aio_ring_file(ctx);517 return -ENOMEM;518 }519 }520 521 for (i = 0; i < nr_pages; i++) {522 struct folio *folio;523 524 folio = __filemap_get_folio(file->f_mapping, i,525 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,526 GFP_USER | __GFP_ZERO);527 if (IS_ERR(folio))528 break;529 530 pr_debug("pid(%d) [%d] folio->count=%d\n", current->pid, i,531 folio_ref_count(folio));532 folio_end_read(folio, true);533 534 ctx->ring_folios[i] = folio;535 }536 ctx->nr_pages = i;537 538 if (unlikely(i != nr_pages)) {539 aio_free_ring(ctx);540 return -ENOMEM;541 }542 543 ctx->mmap_size = nr_pages * PAGE_SIZE;544 pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);545 546 if (mmap_write_lock_killable(mm)) {547 ctx->mmap_size = 0;548 aio_free_ring(ctx);549 return -EINTR;550 }551 552 ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,553 PROT_READ | PROT_WRITE,554 MAP_SHARED, 0, 0, &unused, NULL);555 mmap_write_unlock(mm);556 if (IS_ERR((void *)ctx->mmap_base)) {557 ctx->mmap_size = 0;558 aio_free_ring(ctx);559 return -ENOMEM;560 }561 562 pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);563 564 ctx->user_id = ctx->mmap_base;565 ctx->nr_events = nr_events; /* trusted copy */566 567 ring = folio_address(ctx->ring_folios[0]);568 ring->nr = nr_events; /* user copy */569 ring->id = ~0U;570 ring->head = ring->tail = 0;571 ring->magic = AIO_RING_MAGIC;572 ring->compat_features = AIO_RING_COMPAT_FEATURES;573 ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;574 ring->header_length = sizeof(struct aio_ring);575 flush_dcache_folio(ctx->ring_folios[0]);576 577 return 0;578}579 580#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))581#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))582#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)583 584void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)585{586 struct aio_kiocb *req;587 struct kioctx *ctx;588 unsigned long flags;589 590 /*591 * kiocb didn't come from aio or is neither a read nor a write, hence592 * ignore it.593 */594 if (!(iocb->ki_flags & IOCB_AIO_RW))595 return;596 597 req = container_of(iocb, struct aio_kiocb, rw);598 599 if (WARN_ON_ONCE(!list_empty(&req->ki_list)))600 return;601 602 ctx = req->ki_ctx;603 604 spin_lock_irqsave(&ctx->ctx_lock, flags);605 list_add_tail(&req->ki_list, &ctx->active_reqs);606 req->ki_cancel = cancel;607 spin_unlock_irqrestore(&ctx->ctx_lock, flags);608}609EXPORT_SYMBOL(kiocb_set_cancel_fn);610 611/*612 * free_ioctx() should be RCU delayed to synchronize against the RCU613 * protected lookup_ioctx() and also needs process context to call614 * aio_free_ring(). Use rcu_work.615 */616static HWJS_SUSPENDS void free_ioctx(struct work_struct *work)617{618 struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,619 free_rwork);620 pr_debug("freeing %p\n", ctx);621 622 aio_free_ring(ctx);623 free_percpu(ctx->cpu);624 percpu_ref_exit(&ctx->reqs);625 percpu_ref_exit(&ctx->users);626 kmem_cache_free(kioctx_cachep, ctx);627}628 629static HWJS_SUSPENDS void free_ioctx_reqs(struct percpu_ref *ref)630{631 struct kioctx *ctx = container_of(ref, struct kioctx, reqs);632 633 /* At this point we know that there are no any in-flight requests */634 if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))635 complete(&ctx->rq_wait->comp);636 637 /* Synchronize against RCU protected table->table[] dereferences */638 INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);639 queue_rcu_work(system_wq, &ctx->free_rwork);640}641 642/*643 * When this function runs, the kioctx has been removed from the "hash table"644 * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -645 * now it's safe to cancel any that need to be.646 */647static HWJS_SUSPENDS void free_ioctx_users(struct percpu_ref *ref)648{649 struct kioctx *ctx = container_of(ref, struct kioctx, users);650 struct aio_kiocb *req;651 652 spin_lock_irq(&ctx->ctx_lock);653 654 while (!list_empty(&ctx->active_reqs)) {655 req = list_first_entry(&ctx->active_reqs,656 struct aio_kiocb, ki_list);657 req->ki_cancel(&req->rw);658 list_del_init(&req->ki_list);659 }660 661 spin_unlock_irq(&ctx->ctx_lock);662 663 percpu_ref_kill(&ctx->reqs);664 percpu_ref_put(&ctx->reqs);665}666 667static HWJS_SUSPENDS int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)668{669 unsigned i, new_nr;670 struct kioctx_table *table, *old;671 struct aio_ring *ring;672 673 spin_lock(&mm->ioctx_lock);674 table = rcu_dereference_raw(mm->ioctx_table);675 676 while (1) {677 if (table)678 for (i = 0; i < table->nr; i++)679 if (!rcu_access_pointer(table->table[i])) {680 ctx->id = i;681 rcu_assign_pointer(table->table[i], ctx);682 spin_unlock(&mm->ioctx_lock);683 684 /* While kioctx setup is in progress,685 * we are protected from page migration686 * changes ring_folios by ->ring_lock.687 */688 ring = folio_address(ctx->ring_folios[0]);689 ring->id = ctx->id;690 return 0;691 }692 693 new_nr = (table ? table->nr : 1) * 4;694 spin_unlock(&mm->ioctx_lock);695 696 table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL);697 if (!table)698 return -ENOMEM;699 700 table->nr = new_nr;701 702 spin_lock(&mm->ioctx_lock);703 old = rcu_dereference_raw(mm->ioctx_table);704 705 if (!old) {706 rcu_assign_pointer(mm->ioctx_table, table);707 } else if (table->nr > old->nr) {708 memcpy(table->table, old->table,709 old->nr * sizeof(struct kioctx *));710 711 rcu_assign_pointer(mm->ioctx_table, table);712 kfree_rcu(old, rcu);713 } else {714 kfree(table);715 table = old;716 }717 }718}719 720static void aio_nr_sub(unsigned nr)721{722 spin_lock(&aio_nr_lock);723 if (WARN_ON(aio_nr - nr > aio_nr))724 aio_nr = 0;725 else726 aio_nr -= nr;727 spin_unlock(&aio_nr_lock);728}729 730/* ioctx_alloc731 * Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.732 */733static HWJS_SUSPENDS struct kioctx *ioctx_alloc(unsigned nr_events)734{735 struct mm_struct *mm = current->mm;736 struct kioctx *ctx;737 int err = -ENOMEM;738 739 /*740 * Store the original nr_events -- what userspace passed to io_setup(),741 * for counting against the global limit -- before it changes.742 */743 unsigned int max_reqs = nr_events;744 745 /*746 * We keep track of the number of available ringbuffer slots, to prevent747 * overflow (reqs_available), and we also use percpu counters for this.748 *749 * So since up to half the slots might be on other cpu's percpu counters750 * and unavailable, double nr_events so userspace sees what they751 * expected: additionally, we move req_batch slots to/from percpu752 * counters at a time, so make sure that isn't 0:753 */754 nr_events = max(nr_events, num_possible_cpus() * 4);755 nr_events *= 2;756 757 /* Prevent overflows */758 if (nr_events > (0x10000000U / sizeof(struct io_event))) {759 pr_debug("ENOMEM: nr_events too high\n");760 return ERR_PTR(-EINVAL);761 }762 763 if (!nr_events || (unsigned long)max_reqs > aio_max_nr)764 return ERR_PTR(-EAGAIN);765 766 ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);767 if (!ctx)768 return ERR_PTR(-ENOMEM);769 770 ctx->max_reqs = max_reqs;771 772 spin_lock_init(&ctx->ctx_lock);773 spin_lock_init(&ctx->completion_lock);774 mutex_init(&ctx->ring_lock);775 /* Protect against page migration throughout kiotx setup by keeping776 * the ring_lock mutex held until setup is complete. */777 mutex_lock(&ctx->ring_lock);778 init_waitqueue_head(&ctx->wait);779 780 INIT_LIST_HEAD(&ctx->active_reqs);781 782 if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))783 goto err;784 785 if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))786 goto err;787 788 ctx->cpu = alloc_percpu(struct kioctx_cpu);789 if (!ctx->cpu)790 goto err;791 792 err = aio_setup_ring(ctx, nr_events);793 if (err < 0)794 goto err;795 796 atomic_set(&ctx->reqs_available, ctx->nr_events - 1);797 ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);798 if (ctx->req_batch < 1)799 ctx->req_batch = 1;800 801 /* limit the number of system wide aios */802 spin_lock(&aio_nr_lock);803 if (aio_nr + ctx->max_reqs > aio_max_nr ||804 aio_nr + ctx->max_reqs < aio_nr) {805 spin_unlock(&aio_nr_lock);806 err = -EAGAIN;807 goto err_ctx;808 }809 aio_nr += ctx->max_reqs;810 spin_unlock(&aio_nr_lock);811 812 percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */813 percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */814 815 err = ioctx_add_table(ctx, mm);816 if (err)817 goto err_cleanup;818 819 /* Release the ring_lock mutex now that all setup is complete. */820 mutex_unlock(&ctx->ring_lock);821 822 pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",823 ctx, ctx->user_id, mm, ctx->nr_events);824 return ctx;825 826err_cleanup:827 aio_nr_sub(ctx->max_reqs);828err_ctx:829 atomic_set(&ctx->dead, 1);830 if (ctx->mmap_size)831 vm_munmap(ctx->mmap_base, ctx->mmap_size);832 aio_free_ring(ctx);833err:834 mutex_unlock(&ctx->ring_lock);835 free_percpu(ctx->cpu);836 percpu_ref_exit(&ctx->reqs);837 percpu_ref_exit(&ctx->users);838 kmem_cache_free(kioctx_cachep, ctx);839 pr_debug("error allocating ioctx %d\n", err);840 return ERR_PTR(err);841}842 843/* kill_ioctx844 * Cancels all outstanding aio requests on an aio context. Used845 * when the processes owning a context have all exited to encourage846 * the rapid destruction of the kioctx.847 */848static HWJS_SUSPENDS int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,849 struct ctx_rq_wait *wait)850{851 struct kioctx_table *table;852 853 spin_lock(&mm->ioctx_lock);854 if (atomic_xchg(&ctx->dead, 1)) {855 spin_unlock(&mm->ioctx_lock);856 return -EINVAL;857 }858 859 table = rcu_dereference_raw(mm->ioctx_table);860 WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));861 RCU_INIT_POINTER(table->table[ctx->id], NULL);862 spin_unlock(&mm->ioctx_lock);863 864 /* free_ioctx_reqs() will do the necessary RCU synchronization */865 wake_up_all(&ctx->wait);866 867 /*868 * It'd be more correct to do this in free_ioctx(), after all869 * the outstanding kiocbs have finished - but by then io_destroy870 * has already returned, so io_setup() could potentially return871 * -EAGAIN with no ioctxs actually in use (as far as userspace872 * could tell).873 */874 aio_nr_sub(ctx->max_reqs);875 876 if (ctx->mmap_size)877 vm_munmap(ctx->mmap_base, ctx->mmap_size);878 879 ctx->rq_wait = wait;880 percpu_ref_kill(&ctx->users);881 return 0;882}883 884/*885 * exit_aio: called when the last user of mm goes away. At this point, there is886 * no way for any new requests to be submited or any of the io_* syscalls to be887 * called on the context.888 *889 * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on890 * them.891 */892void exit_aio(struct mm_struct *mm)893{894 struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);895 struct ctx_rq_wait wait;896 int i, skipped;897 898 if (!table)899 return;900 901 atomic_set(&wait.count, table->nr);902 init_completion(&wait.comp);903 904 skipped = 0;905 for (i = 0; i < table->nr; ++i) {906 struct kioctx *ctx =907 rcu_dereference_protected(table->table[i], true);908 909 if (!ctx) {910 skipped++;911 continue;912 }913 914 /*915 * We don't need to bother with munmap() here - exit_mmap(mm)916 * is coming and it'll unmap everything. And we simply can't,917 * this is not necessarily our ->mm.918 * Since kill_ioctx() uses non-zero ->mmap_size as indicator919 * that it needs to unmap the area, just set it to 0.920 */921 ctx->mmap_size = 0;922 kill_ioctx(mm, ctx, &wait);923 }924 925 if (!atomic_sub_and_test(skipped, &wait.count)) {926 /* Wait until all IO for the context are done. */927 wait_for_completion(&wait.comp);928 }929 930 RCU_INIT_POINTER(mm->ioctx_table, NULL);931 kfree(table);932}933 934static void put_reqs_available(struct kioctx *ctx, unsigned nr)935{936 struct kioctx_cpu *kcpu;937 unsigned long flags;938 939 local_irq_save(flags);940 kcpu = this_cpu_ptr(ctx->cpu);941 kcpu->reqs_available += nr;942 943 while (kcpu->reqs_available >= ctx->req_batch * 2) {944 kcpu->reqs_available -= ctx->req_batch;945 atomic_add(ctx->req_batch, &ctx->reqs_available);946 }947 948 local_irq_restore(flags);949}950 951static bool __get_reqs_available(struct kioctx *ctx)952{953 struct kioctx_cpu *kcpu;954 bool ret = false;955 unsigned long flags;956 957 local_irq_save(flags);958 kcpu = this_cpu_ptr(ctx->cpu);959 if (!kcpu->reqs_available) {960 int avail = atomic_read(&ctx->reqs_available);961 962 do {963 if (avail < ctx->req_batch)964 goto out;965 } while (!atomic_try_cmpxchg(&ctx->reqs_available,966 &avail, avail - ctx->req_batch));967 968 kcpu->reqs_available += ctx->req_batch;969 }970 971 ret = true;972 kcpu->reqs_available--;973out:974 local_irq_restore(flags);975 return ret;976}977 978/* refill_reqs_available979 * Updates the reqs_available reference counts used for tracking the980 * number of free slots in the completion ring. This can be called981 * from aio_complete() (to optimistically update reqs_available) or982 * from aio_get_req() (the we're out of events case). It must be983 * called holding ctx->completion_lock.984 */985static void refill_reqs_available(struct kioctx *ctx, unsigned head,986 unsigned tail)987{988 unsigned events_in_ring, completed;989 990 /* Clamp head since userland can write to it. */991 head %= ctx->nr_events;992 if (head <= tail)993 events_in_ring = tail - head;994 else995 events_in_ring = ctx->nr_events - (head - tail);996 997 completed = ctx->completed_events;998 if (events_in_ring < completed)999 completed -= events_in_ring;1000 else1001 completed = 0;1002 1003 if (!completed)1004 return;1005 1006 ctx->completed_events -= completed;1007 put_reqs_available(ctx, completed);1008}1009 1010/* user_refill_reqs_available1011 * Called to refill reqs_available when aio_get_req() encounters an1012 * out of space in the completion ring.1013 */1014static void user_refill_reqs_available(struct kioctx *ctx)1015{1016 spin_lock_irq(&ctx->completion_lock);1017 if (ctx->completed_events) {1018 struct aio_ring *ring;1019 unsigned head;1020 1021 /* Access of ring->head may race with aio_read_events_ring()1022 * here, but that's okay since whether we read the old version1023 * or the new version, and either will be valid. The important1024 * part is that head cannot pass tail since we prevent1025 * aio_complete() from updating tail by holding1026 * ctx->completion_lock. Even if head is invalid, the check1027 * against ctx->completed_events below will make sure we do the1028 * safe/right thing.1029 */1030 ring = folio_address(ctx->ring_folios[0]);1031 head = ring->head;1032 1033 refill_reqs_available(ctx, head, ctx->tail);1034 }1035 1036 spin_unlock_irq(&ctx->completion_lock);1037}1038 1039static bool get_reqs_available(struct kioctx *ctx)1040{1041 if (__get_reqs_available(ctx))1042 return true;1043 user_refill_reqs_available(ctx);1044 return __get_reqs_available(ctx);1045}1046 1047/* aio_get_req1048 * Allocate a slot for an aio request.1049 * Returns NULL if no requests are free.1050 *1051 * The refcount is initialized to 2 - one for the async op completion,1052 * one for the synchronous code that does this.1053 */1054static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)1055{1056 struct aio_kiocb *req;1057 1058 req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);1059 if (unlikely(!req))1060 return NULL;1061 1062 if (unlikely(!get_reqs_available(ctx))) {1063 kmem_cache_free(kiocb_cachep, req);1064 return NULL;1065 }1066 1067 percpu_ref_get(&ctx->reqs);1068 req->ki_ctx = ctx;1069 INIT_LIST_HEAD(&req->ki_list);1070 refcount_set(&req->ki_refcnt, 2);1071 req->ki_eventfd = NULL;1072 return req;1073}1074 1075static struct kioctx *lookup_ioctx(unsigned long ctx_id)1076{1077 struct aio_ring __user *ring = (void __user *)ctx_id;1078 struct mm_struct *mm = current->mm;1079 struct kioctx *ctx, *ret = NULL;1080 struct kioctx_table *table;1081 unsigned id;1082 1083 if (get_user(id, &ring->id))1084 return NULL;1085 1086 rcu_read_lock();1087 table = rcu_dereference(mm->ioctx_table);1088 1089 if (!table || id >= table->nr)1090 goto out;1091 1092 id = array_index_nospec(id, table->nr);1093 ctx = rcu_dereference(table->table[id]);1094 if (ctx && ctx->user_id == ctx_id) {1095 if (percpu_ref_tryget_live(&ctx->users))1096 ret = ctx;1097 }1098out:1099 rcu_read_unlock();1100 return ret;1101}1102 1103static HWJS_SUSPENDS inline void iocb_destroy(struct aio_kiocb *iocb)1104{1105 if (iocb->ki_eventfd)1106 eventfd_ctx_put(iocb->ki_eventfd);1107 if (iocb->ki_filp)1108 fput(iocb->ki_filp);1109 percpu_ref_put(&iocb->ki_ctx->reqs);1110 kmem_cache_free(kiocb_cachep, iocb);1111}1112 1113struct aio_waiter {1114 struct wait_queue_entry w;1115 size_t min_nr;1116};1117 1118/* aio_complete1119 * Called when the io request on the given iocb is complete.1120 */1121static HWJS_SUSPENDS void aio_complete(struct aio_kiocb *iocb)1122{1123 struct kioctx *ctx = iocb->ki_ctx;1124 struct aio_ring *ring;1125 struct io_event *ev_page, *event;1126 unsigned tail, pos, head, avail;1127 unsigned long flags;1128 1129 /*1130 * Add a completion event to the ring buffer. Must be done holding1131 * ctx->completion_lock to prevent other code from messing with the tail1132 * pointer since we might be called from irq context.1133 */1134 spin_lock_irqsave(&ctx->completion_lock, flags);1135 1136 tail = ctx->tail;1137 pos = tail + AIO_EVENTS_OFFSET;1138 1139 if (++tail >= ctx->nr_events)1140 tail = 0;1141 1142 ev_page = folio_address(ctx->ring_folios[pos / AIO_EVENTS_PER_PAGE]);1143 event = ev_page + pos % AIO_EVENTS_PER_PAGE;1144 1145 *event = iocb->ki_res;1146 1147 flush_dcache_folio(ctx->ring_folios[pos / AIO_EVENTS_PER_PAGE]);1148 1149 pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,1150 (void __user *)(unsigned long)iocb->ki_res.obj,1151 iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);1152 1153 /* after flagging the request as done, we1154 * must never even look at it again1155 */1156 smp_wmb(); /* make event visible before updating tail */1157 1158 ctx->tail = tail;1159 1160 ring = folio_address(ctx->ring_folios[0]);1161 head = ring->head;1162 ring->tail = tail;1163 flush_dcache_folio(ctx->ring_folios[0]);1164 1165 ctx->completed_events++;1166 if (ctx->completed_events > 1)1167 refill_reqs_available(ctx, head, tail);1168 1169 avail = tail > head1170 ? tail - head1171 : tail + ctx->nr_events - head;1172 spin_unlock_irqrestore(&ctx->completion_lock, flags);1173 1174 pr_debug("added to ring %p at [%u]\n", iocb, tail);1175 1176 /*1177 * Check if the user asked us to deliver the result through an1178 * eventfd. The eventfd_signal() function is safe to be called1179 * from IRQ context.1180 */1181 if (iocb->ki_eventfd)1182 eventfd_signal(iocb->ki_eventfd);1183 1184 /*1185 * We have to order our ring_info tail store above and test1186 * of the wait list below outside the wait lock. This is1187 * like in wake_up_bit() where clearing a bit has to be1188 * ordered with the unlocked test.1189 */1190 smp_mb();1191 1192 if (waitqueue_active(&ctx->wait)) {1193 struct aio_waiter *curr, *next;1194 unsigned long flags;1195 1196 spin_lock_irqsave(&ctx->wait.lock, flags);1197 list_for_each_entry_safe(curr, next, &ctx->wait.head, w.entry)1198 if (avail >= curr->min_nr) {1199 wake_up_process(curr->w.private);1200 list_del_init_careful(&curr->w.entry);1201 }1202 spin_unlock_irqrestore(&ctx->wait.lock, flags);1203 }1204}1205 1206static HWJS_SUSPENDS inline void iocb_put(struct aio_kiocb *iocb)1207{1208 if (refcount_dec_and_test(&iocb->ki_refcnt)) {1209 aio_complete(iocb);1210 iocb_destroy(iocb);1211 }1212}1213 1214/* aio_read_events_ring1215 * Pull an event off of the ioctx's event ring. Returns the number of1216 * events fetched1217 */1218static HWJS_SUSPENDS long aio_read_events_ring(struct kioctx *ctx,1219 struct io_event __user *event, long nr)1220{1221 struct aio_ring *ring;1222 unsigned head, tail, pos;1223 long ret = 0;1224 int copy_ret;1225 1226 /*1227 * The mutex can block and wake us up and that will cause1228 * wait_event_interruptible_hrtimeout() to schedule without sleeping1229 * and repeat. This should be rare enough that it doesn't cause1230 * peformance issues. See the comment in read_events() for more detail.1231 */1232 sched_annotate_sleep();1233 mutex_lock(&ctx->ring_lock);1234 1235 /* Access to ->ring_folios here is protected by ctx->ring_lock. */1236 ring = folio_address(ctx->ring_folios[0]);1237 head = ring->head;1238 tail = ring->tail;1239 1240 /*1241 * Ensure that once we've read the current tail pointer, that1242 * we also see the events that were stored up to the tail.1243 */1244 smp_rmb();1245 1246 pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);1247 1248 if (head == tail)1249 goto out;1250 1251 head %= ctx->nr_events;1252 tail %= ctx->nr_events;1253 1254 while (ret < nr) {1255 long avail;1256 struct io_event *ev;1257 struct folio *folio;1258 1259 avail = (head <= tail ? tail : ctx->nr_events) - head;1260 if (head == tail)1261 break;1262 1263 pos = head + AIO_EVENTS_OFFSET;1264 folio = ctx->ring_folios[pos / AIO_EVENTS_PER_PAGE];1265 pos %= AIO_EVENTS_PER_PAGE;1266 1267 avail = min(avail, nr - ret);1268 avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);1269 1270 ev = folio_address(folio);1271 copy_ret = copy_to_user(event + ret, ev + pos,1272 sizeof(*ev) * avail);1273 1274 if (unlikely(copy_ret)) {1275 ret = -EFAULT;1276 goto out;1277 }1278 1279 ret += avail;1280 head += avail;1281 head %= ctx->nr_events;1282 }1283 1284 ring = folio_address(ctx->ring_folios[0]);1285 ring->head = head;1286 flush_dcache_folio(ctx->ring_folios[0]);1287 1288 pr_debug("%li h%u t%u\n", ret, head, tail);1289out:1290 mutex_unlock(&ctx->ring_lock);1291 1292 return ret;1293}1294 1295static HWJS_SUSPENDS bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,1296 struct io_event __user *event, long *i)1297{1298 long ret = aio_read_events_ring(ctx, event + *i, nr - *i);1299 1300 if (ret > 0)1301 *i += ret;1302 1303 if (unlikely(atomic_read(&ctx->dead)))1304 ret = -EINVAL;1305 1306 if (!*i)1307 *i = ret;1308 1309 return ret < 0 || *i >= min_nr;1310}1311 1312static HWJS_SUSPENDS long read_events(struct kioctx *ctx, long min_nr, long nr,1313 struct io_event __user *event,1314 ktime_t until)1315{1316 struct hrtimer_sleeper t;1317 struct aio_waiter w;1318 long ret = 0, ret2 = 0;1319 1320 /*1321 * Note that aio_read_events() is being called as the conditional - i.e.1322 * we're calling it after prepare_to_wait() has set task state to1323 * TASK_INTERRUPTIBLE.1324 *1325 * But aio_read_events() can block, and if it blocks it's going to flip1326 * the task state back to TASK_RUNNING.1327 *1328 * This should be ok, provided it doesn't flip the state back to1329 * TASK_RUNNING and return 0 too much - that causes us to spin. That1330 * will only happen if the mutex_lock() call blocks, and we then find1331 * the ringbuffer empty. So in practice we should be ok, but it's1332 * something to be aware of when touching this code.1333 */1334 aio_read_events(ctx, min_nr, nr, event, &ret);1335 if (until == 0 || ret < 0 || ret >= min_nr)1336 return ret;1337 1338 hrtimer_init_sleeper_on_stack(&t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);1339 if (until != KTIME_MAX) {1340 hrtimer_set_expires_range_ns(&t.timer, until, current->timer_slack_ns);1341 hrtimer_sleeper_start_expires(&t, HRTIMER_MODE_REL);1342 }1343 1344 init_wait(&w.w);1345 1346 while (1) {1347 unsigned long nr_got = ret;1348 1349 w.min_nr = min_nr - ret;1350 1351 ret2 = prepare_to_wait_event(&ctx->wait, &w.w, TASK_INTERRUPTIBLE);1352 if (!ret2 && !t.task)1353 ret2 = -ETIME;1354 1355 if (aio_read_events(ctx, min_nr, nr, event, &ret) || ret2)1356 break;1357 1358 if (nr_got == ret)1359 schedule();1360 }1361 1362 finish_wait(&ctx->wait, &w.w);1363 hrtimer_cancel(&t.timer);1364 destroy_hrtimer_on_stack(&t.timer);1365 1366 return ret;1367}1368 1369/* sys_io_setup:1370 * Create an aio_context capable of receiving at least nr_events.1371 * ctxp must not point to an aio_context that already exists, and1372 * must be initialized to 0 prior to the call. On successful1373 * creation of the aio_context, *ctxp is filled in with the resulting 1374 * handle. May fail with -EINVAL if *ctxp is not initialized,1375 * if the specified nr_events exceeds internal limits. May fail 1376 * with -EAGAIN if the specified nr_events exceeds the user's limit 1377 * of available events. May fail with -ENOMEM if insufficient kernel1378 * resources are available. May fail with -EFAULT if an invalid1379 * pointer is passed for ctxp. Will fail with -ENOSYS if not1380 * implemented.1381 */1382SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)1383{1384 struct kioctx *ioctx = NULL;1385 unsigned long ctx;1386 long ret;1387 1388 ret = get_user(ctx, ctxp);1389 if (unlikely(ret))1390 goto out;1391 1392 ret = -EINVAL;1393 if (unlikely(ctx || nr_events == 0)) {1394 pr_debug("EINVAL: ctx %lu nr_events %u\n",1395 ctx, nr_events);1396 goto out;1397 }1398 1399 ioctx = ioctx_alloc(nr_events);1400 ret = PTR_ERR(ioctx);1401 if (!IS_ERR(ioctx)) {1402 ret = put_user(ioctx->user_id, ctxp);1403 if (ret)1404 kill_ioctx(current->mm, ioctx, NULL);1405 percpu_ref_put(&ioctx->users);1406 }1407 1408out:1409 return ret;1410}1411 1412#ifdef CONFIG_COMPAT1413COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)1414{1415 struct kioctx *ioctx = NULL;1416 unsigned long ctx;1417 long ret;1418 1419 ret = get_user(ctx, ctx32p);1420 if (unlikely(ret))1421 goto out;1422 1423 ret = -EINVAL;1424 if (unlikely(ctx || nr_events == 0)) {1425 pr_debug("EINVAL: ctx %lu nr_events %u\n",1426 ctx, nr_events);1427 goto out;1428 }1429 1430 ioctx = ioctx_alloc(nr_events);1431 ret = PTR_ERR(ioctx);1432 if (!IS_ERR(ioctx)) {1433 /* truncating is ok because it's a user address */1434 ret = put_user((u32)ioctx->user_id, ctx32p);1435 if (ret)1436 kill_ioctx(current->mm, ioctx, NULL);1437 percpu_ref_put(&ioctx->users);1438 }1439 1440out:1441 return ret;1442}1443#endif1444 1445/* sys_io_destroy:1446 * Destroy the aio_context specified. May cancel any outstanding 1447 * AIOs and block on completion. Will fail with -ENOSYS if not1448 * implemented. May fail with -EINVAL if the context pointed to1449 * is invalid.1450 */1451SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)1452{1453 struct kioctx *ioctx = lookup_ioctx(ctx);1454 if (likely(NULL != ioctx)) {1455 struct ctx_rq_wait wait;1456 int ret;1457 1458 init_completion(&wait.comp);1459 atomic_set(&wait.count, 1);1460 1461 /* Pass requests_done to kill_ioctx() where it can be set1462 * in a thread-safe way. If we try to set it here then we have1463 * a race condition if two io_destroy() called simultaneously.1464 */1465 ret = kill_ioctx(current->mm, ioctx, &wait);1466 percpu_ref_put(&ioctx->users);1467 1468 /* Wait until all IO for the context are done. Otherwise kernel1469 * keep using user-space buffers even if user thinks the context1470 * is destroyed.1471 */1472 if (!ret)1473 wait_for_completion(&wait.comp);1474 1475 return ret;1476 }1477 pr_debug("EINVAL: invalid context id\n");1478 return -EINVAL;1479}1480 1481static void aio_remove_iocb(struct aio_kiocb *iocb)1482{1483 struct kioctx *ctx = iocb->ki_ctx;1484 unsigned long flags;1485 1486 spin_lock_irqsave(&ctx->ctx_lock, flags);1487 list_del(&iocb->ki_list);1488 spin_unlock_irqrestore(&ctx->ctx_lock, flags);1489}1490 1491static HWJS_SUSPENDS void aio_complete_rw(struct kiocb *kiocb, long res)1492{1493 struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);1494 1495 if (!list_empty_careful(&iocb->ki_list))1496 aio_remove_iocb(iocb);1497 1498 if (kiocb->ki_flags & IOCB_WRITE) {1499 struct inode *inode = file_inode(kiocb->ki_filp);1500 1501 if (S_ISREG(inode->i_mode))1502 kiocb_end_write(kiocb);1503 }1504 1505 iocb->ki_res.res = res;1506 iocb->ki_res.res2 = 0;1507 iocb_put(iocb);1508}1509 1510static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb, int rw_type)1511{1512 int ret;1513 1514 req->ki_complete = aio_complete_rw;1515 req->private = NULL;1516 req->ki_pos = iocb->aio_offset;1517 req->ki_flags = req->ki_filp->f_iocb_flags | IOCB_AIO_RW;1518 if (iocb->aio_flags & IOCB_FLAG_RESFD)1519 req->ki_flags |= IOCB_EVENTFD;1520 if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {1521 /*1522 * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then1523 * aio_reqprio is interpreted as an I/O scheduling1524 * class and priority.1525 */1526 ret = ioprio_check_cap(iocb->aio_reqprio);1527 if (ret) {1528 pr_debug("aio ioprio check cap error: %d\n", ret);1529 return ret;1530 }1531 1532 req->ki_ioprio = iocb->aio_reqprio;1533 } else1534 req->ki_ioprio = get_current_ioprio();1535 1536 ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags, rw_type);1537 if (unlikely(ret))1538 return ret;1539 1540 req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */1541 return 0;1542}1543 1544static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,1545 struct iovec **iovec, bool vectored, bool compat,1546 struct iov_iter *iter)1547{1548 void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;1549 size_t len = iocb->aio_nbytes;1550 1551 if (!vectored) {1552 ssize_t ret = import_ubuf(rw, buf, len, iter);1553 *iovec = NULL;1554 return ret;1555 }1556 1557 return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);1558}1559 1560static HWJS_SUSPENDS inline void aio_rw_done(struct kiocb *req, ssize_t ret)1561{1562 switch (ret) {1563 case -EIOCBQUEUED:1564 break;1565 case -ERESTARTSYS:1566 case -ERESTARTNOINTR:1567 case -ERESTARTNOHAND:1568 case -ERESTART_RESTARTBLOCK:1569 /*1570 * There's no easy way to restart the syscall since other AIO's1571 * may be already running. Just fail this IO with EINTR.1572 */1573 ret = -EINTR;1574 fallthrough;1575 default:1576 req->ki_complete(req, ret);1577 }1578}1579 1580static HWJS_SUSPENDS int aio_read(struct kiocb *req, const struct iocb *iocb,1581 bool vectored, bool compat)1582{1583 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;1584 struct iov_iter iter;1585 struct file *file;1586 int ret;1587 1588 ret = aio_prep_rw(req, iocb, READ);1589 if (ret)1590 return ret;1591 file = req->ki_filp;1592 if (unlikely(!(file->f_mode & FMODE_READ)))1593 return -EBADF;1594 if (unlikely(!file->f_op->read_iter))1595 return -EINVAL;1596 1597 ret = aio_setup_rw(ITER_DEST, iocb, &iovec, vectored, compat, &iter);1598 if (ret < 0)1599 return ret;1600 ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));1601 if (!ret)1602 aio_rw_done(req, file->f_op->read_iter(req, &iter));1603 kfree(iovec);1604 return ret;1605}1606 1607static HWJS_SUSPENDS int aio_write(struct kiocb *req, const struct iocb *iocb,1608 bool vectored, bool compat)1609{1610 struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;1611 struct iov_iter iter;1612 struct file *file;1613 int ret;1614 1615 ret = aio_prep_rw(req, iocb, WRITE);1616 if (ret)1617 return ret;1618 file = req->ki_filp;1619 1620 if (unlikely(!(file->f_mode & FMODE_WRITE)))1621 return -EBADF;1622 if (unlikely(!file->f_op->write_iter))1623 return -EINVAL;1624 1625 ret = aio_setup_rw(ITER_SOURCE, iocb, &iovec, vectored, compat, &iter);1626 if (ret < 0)1627 return ret;1628 ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));1629 if (!ret) {1630 if (S_ISREG(file_inode(file)->i_mode))1631 kiocb_start_write(req);1632 req->ki_flags |= IOCB_WRITE;1633 aio_rw_done(req, file->f_op->write_iter(req, &iter));1634 }1635 kfree(iovec);1636 return ret;1637}1638 1639static HWJS_SUSPENDS void aio_fsync_work(struct work_struct *work)1640{1641 struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);1642 const struct cred *old_cred = override_creds(iocb->fsync.creds);1643 1644 iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);1645 revert_creds(old_cred);1646 put_cred(iocb->fsync.creds);1647 iocb_put(iocb);1648}1649 1650static HWJS_SUSPENDS int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,1651 bool datasync)1652{1653 if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||1654 iocb->aio_rw_flags))1655 return -EINVAL;1656 1657 if (unlikely(!req->file->f_op->fsync))1658 return -EINVAL;1659 1660 req->creds = prepare_creds();1661 if (!req->creds)1662 return -ENOMEM;1663 1664 req->datasync = datasync;1665 INIT_WORK(&req->work, aio_fsync_work);1666 schedule_work(&req->work);1667 return 0;1668}1669 1670static HWJS_SUSPENDS void aio_poll_put_work(struct work_struct *work)1671{1672 struct poll_iocb *req = container_of(work, struct poll_iocb, work);1673 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);1674 1675 iocb_put(iocb);1676}1677 1678/*1679 * Safely lock the waitqueue which the request is on, synchronizing with the1680 * case where the ->poll() provider decides to free its waitqueue early.1681 *1682 * Returns true on success, meaning that req->head->lock was locked, req->wait1683 * is on req->head, and an RCU read lock was taken. Returns false if the1684 * request was already removed from its waitqueue (which might no longer exist).1685 */1686static bool poll_iocb_lock_wq(struct poll_iocb *req)1687{1688 wait_queue_head_t *head;1689 1690 /*1691 * While we hold the waitqueue lock and the waitqueue is nonempty,1692 * wake_up_pollfree() will wait for us. However, taking the waitqueue1693 * lock in the first place can race with the waitqueue being freed.1694 *1695 * We solve this as eventpoll does: by taking advantage of the fact that1696 * all users of wake_up_pollfree() will RCU-delay the actual free. If1697 * we enter rcu_read_lock() and see that the pointer to the queue is1698 * non-NULL, we can then lock it without the memory being freed out from1699 * under us, then check whether the request is still on the queue.1700 *1701 * Keep holding rcu_read_lock() as long as we hold the queue lock, in1702 * case the caller deletes the entry from the queue, leaving it empty.1703 * In that case, only RCU prevents the queue memory from being freed.1704 */1705 rcu_read_lock();1706 head = smp_load_acquire(&req->head);1707 if (head) {1708 spin_lock(&head->lock);1709 if (!list_empty(&req->wait.entry))1710 return true;1711 spin_unlock(&head->lock);1712 }1713 rcu_read_unlock();1714 return false;1715}1716 1717static void poll_iocb_unlock_wq(struct poll_iocb *req)1718{1719 spin_unlock(&req->head->lock);1720 rcu_read_unlock();1721}1722 1723static HWJS_SUSPENDS void aio_poll_complete_work(struct work_struct *work)1724{1725 struct poll_iocb *req = container_of(work, struct poll_iocb, work);1726 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);1727 struct poll_table_struct pt = { ._key = req->events };1728 struct kioctx *ctx = iocb->ki_ctx;1729 __poll_t mask = 0;1730 1731 if (!READ_ONCE(req->cancelled))1732 mask = vfs_poll(req->file, &pt) & req->events;1733 1734 /*1735 * Note that ->ki_cancel callers also delete iocb from active_reqs after1736 * calling ->ki_cancel. We need the ctx_lock roundtrip here to1737 * synchronize with them. In the cancellation case the list_del_init1738 * itself is not actually needed, but harmless so we keep it in to1739 * avoid further branches in the fast path.1740 */1741 spin_lock_irq(&ctx->ctx_lock);1742 if (poll_iocb_lock_wq(req)) {1743 if (!mask && !READ_ONCE(req->cancelled)) {1744 /*1745 * The request isn't actually ready to be completed yet.1746 * Reschedule completion if another wakeup came in.1747 */1748 if (req->work_need_resched) {1749 schedule_work(&req->work);1750 req->work_need_resched = false;1751 } else {1752 req->work_scheduled = false;1753 }1754 poll_iocb_unlock_wq(req);1755 spin_unlock_irq(&ctx->ctx_lock);1756 return;1757 }1758 list_del_init(&req->wait.entry);1759 poll_iocb_unlock_wq(req);1760 } /* else, POLLFREE has freed the waitqueue, so we must complete */1761 list_del_init(&iocb->ki_list);1762 iocb->ki_res.res = mangle_poll(mask);1763 spin_unlock_irq(&ctx->ctx_lock);1764 1765 iocb_put(iocb);1766}1767 1768/* assumes we are called with irqs disabled */1769static HWJS_SUSPENDS int aio_poll_cancel(struct kiocb *iocb)1770{1771 struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);1772 struct poll_iocb *req = &aiocb->poll;1773 1774 if (poll_iocb_lock_wq(req)) {1775 WRITE_ONCE(req->cancelled, true);1776 if (!req->work_scheduled) {1777 schedule_work(&aiocb->poll.work);1778 req->work_scheduled = true;1779 }1780 poll_iocb_unlock_wq(req);1781 } /* else, the request was force-cancelled by POLLFREE already */1782 1783 return 0;1784}1785 1786static HWJS_SUSPENDS int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,1787 void *key)1788{1789 struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);1790 struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);1791 __poll_t mask = key_to_poll(key);1792 unsigned long flags;1793 1794 /* for instances that support it check for an event match first: */1795 if (mask && !(mask & req->events))1796 return 0;1797 1798 /*1799 * Complete the request inline if possible. This requires that three1800 * conditions be met:1801 * 1. An event mask must have been passed. If a plain wakeup was done1802 * instead, then mask == 0 and we have to call vfs_poll() to get1803 * the events, so inline completion isn't possible.1804 * 2. The completion work must not have already been scheduled.1805 * 3. ctx_lock must not be busy. We have to use trylock because we1806 * already hold the waitqueue lock, so this inverts the normal1807 * locking order. Use irqsave/irqrestore because not all1808 * filesystems (e.g. fuse) call this function with IRQs disabled,1809 * yet IRQs have to be disabled before ctx_lock is obtained.1810 */1811 if (mask && !req->work_scheduled &&1812 spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {1813 struct kioctx *ctx = iocb->ki_ctx;1814 1815 list_del_init(&req->wait.entry);1816 list_del(&iocb->ki_list);1817 iocb->ki_res.res = mangle_poll(mask);1818 if (iocb->ki_eventfd && !eventfd_signal_allowed()) {1819 iocb = NULL;1820 INIT_WORK(&req->work, aio_poll_put_work);1821 schedule_work(&req->work);1822 }1823 spin_unlock_irqrestore(&ctx->ctx_lock, flags);1824 if (iocb)1825 iocb_put(iocb);1826 } else {1827 /*1828 * Schedule the completion work if needed. If it was already1829 * scheduled, record that another wakeup came in.1830 *1831 * Don't remove the request from the waitqueue here, as it might1832 * not actually be complete yet (we won't know until vfs_poll()1833 * is called), and we must not miss any wakeups. POLLFREE is an1834 * exception to this; see below.1835 */1836 if (req->work_scheduled) {1837 req->work_need_resched = true;1838 } else {1839 schedule_work(&req->work);1840 req->work_scheduled = true;1841 }1842 1843 /*1844 * If the waitqueue is being freed early but we can't complete1845 * the request inline, we have to tear down the request as best1846 * we can. That means immediately removing the request from its1847 * waitqueue and preventing all further accesses to the1848 * waitqueue via the request. We also need to schedule the1849 * completion work (done above). Also mark the request as1850 * cancelled, to potentially skip an unneeded call to ->poll().1851 */1852 if (mask & POLLFREE) {1853 WRITE_ONCE(req->cancelled, true);1854 list_del_init(&req->wait.entry);1855 1856 /*1857 * Careful: this *must* be the last step, since as soon1858 * as req->head is NULL'ed out, the request can be1859 * completed and freed, since aio_poll_complete_work()1860 * will no longer need to take the waitqueue lock.1861 */1862 smp_store_release(&req->head, NULL);1863 }1864 }1865 return 1;1866}1867 1868struct aio_poll_table {1869 struct poll_table_struct pt;1870 struct aio_kiocb *iocb;1871 bool queued;1872 int error;1873};1874 1875static void1876aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,1877 struct poll_table_struct *p)1878{1879 struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);1880 1881 /* multiple wait queues per file are not supported */1882 if (unlikely(pt->queued)) {1883 pt->error = -EINVAL;1884 return;1885 }1886 1887 pt->queued = true;1888 pt->error = 0;1889 pt->iocb->poll.head = head;1890 add_wait_queue(head, &pt->iocb->poll.wait);1891}1892 1893static HWJS_SUSPENDS int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)1894{1895 struct kioctx *ctx = aiocb->ki_ctx;1896 struct poll_iocb *req = &aiocb->poll;1897 struct aio_poll_table apt;1898 bool cancel = false;1899 __poll_t mask;1900 1901 /* reject any unknown events outside the normal event mask. */1902 if ((u16)iocb->aio_buf != iocb->aio_buf)1903 return -EINVAL;1904 /* reject fields that are not defined for poll */1905 if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)1906 return -EINVAL;1907 1908 INIT_WORK(&req->work, aio_poll_complete_work);1909 req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;1910 1911 req->head = NULL;1912 req->cancelled = false;1913 req->work_scheduled = false;1914 req->work_need_resched = false;1915 1916 apt.pt._qproc = aio_poll_queue_proc;1917 apt.pt._key = req->events;1918 apt.iocb = aiocb;1919 apt.queued = false;1920 apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */1921 1922 /* initialized the list so that we can do list_empty checks */1923 INIT_LIST_HEAD(&req->wait.entry);1924 init_waitqueue_func_entry(&req->wait, aio_poll_wake);1925 1926 mask = vfs_poll(req->file, &apt.pt) & req->events;1927 spin_lock_irq(&ctx->ctx_lock);1928 if (likely(apt.queued)) {1929 bool on_queue = poll_iocb_lock_wq(req);1930 1931 if (!on_queue || req->work_scheduled) {1932 /*1933 * aio_poll_wake() already either scheduled the async1934 * completion work, or completed the request inline.1935 */1936 if (apt.error) /* unsupported case: multiple queues */1937 cancel = true;1938 apt.error = 0;1939 mask = 0;1940 }1941 if (mask || apt.error) {1942 /* Steal to complete synchronously. */1943 list_del_init(&req->wait.entry);1944 } else if (cancel) {1945 /* Cancel if possible (may be too late though). */1946 WRITE_ONCE(req->cancelled, true);1947 } else if (on_queue) {1948 /*1949 * Actually waiting for an event, so add the request to1950 * active_reqs so that it can be cancelled if needed.1951 */1952 list_add_tail(&aiocb->ki_list, &ctx->active_reqs);1953 aiocb->ki_cancel = aio_poll_cancel;1954 }1955 if (on_queue)1956 poll_iocb_unlock_wq(req);1957 }1958 if (mask) { /* no async, we'd stolen it */1959 aiocb->ki_res.res = mangle_poll(mask);1960 apt.error = 0;1961 }1962 spin_unlock_irq(&ctx->ctx_lock);1963 if (mask)1964 iocb_put(aiocb);1965 return apt.error;1966}1967 1968static HWJS_SUSPENDS int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,1969 struct iocb __user *user_iocb, struct aio_kiocb *req,1970 bool compat)1971{1972 req->ki_filp = fget(iocb->aio_fildes);1973 if (unlikely(!req->ki_filp))1974 return -EBADF;1975 1976 if (iocb->aio_flags & IOCB_FLAG_RESFD) {1977 struct eventfd_ctx *eventfd;1978 /*1979 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an1980 * instance of the file* now. The file descriptor must be1981 * an eventfd() fd, and will be signaled for each completed1982 * event using the eventfd_signal() function.1983 */1984 eventfd = eventfd_ctx_fdget(iocb->aio_resfd);1985 if (IS_ERR(eventfd))1986 return PTR_ERR(eventfd);1987 1988 req->ki_eventfd = eventfd;1989 }1990 1991 if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {1992 pr_debug("EFAULT: aio_key\n");1993 return -EFAULT;1994 }1995 1996 req->ki_res.obj = (u64)(unsigned long)user_iocb;1997 req->ki_res.data = iocb->aio_data;1998 req->ki_res.res = 0;1999 req->ki_res.res2 = 0;2000 2001 switch (iocb->aio_lio_opcode) {2002 case IOCB_CMD_PREAD:2003 return aio_read(&req->rw, iocb, false, compat);2004 case IOCB_CMD_PWRITE:2005 return aio_write(&req->rw, iocb, false, compat);2006 case IOCB_CMD_PREADV:2007 return aio_read(&req->rw, iocb, true, compat);2008 case IOCB_CMD_PWRITEV:2009 return aio_write(&req->rw, iocb, true, compat);2010 case IOCB_CMD_FSYNC:2011 return aio_fsync(&req->fsync, iocb, false);2012 case IOCB_CMD_FDSYNC:2013 return aio_fsync(&req->fsync, iocb, true);2014 case IOCB_CMD_POLL:2015 return aio_poll(req, iocb);2016 default:2017 pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);2018 return -EINVAL;2019 }2020}2021 2022static HWJS_SUSPENDS int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,2023 bool compat)2024{2025 struct aio_kiocb *req;2026 struct iocb iocb;2027 int err;2028 2029 if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))2030 return -EFAULT;2031 2032 /* enforce forwards compatibility on users */2033 if (unlikely(iocb.aio_reserved2)) {2034 pr_debug("EINVAL: reserve field set\n");2035 return -EINVAL;2036 }2037 2038 /* prevent overflows */2039 if (unlikely(2040 (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||2041 (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||2042 ((ssize_t)iocb.aio_nbytes < 0)2043 )) {2044 pr_debug("EINVAL: overflow check\n");2045 return -EINVAL;2046 }2047 2048 req = aio_get_req(ctx);2049 if (unlikely(!req))2050 return -EAGAIN;2051 2052 err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);2053 2054 /* Done with the synchronous reference */2055 iocb_put(req);2056 2057 /*2058 * If err is 0, we'd either done aio_complete() ourselves or have2059 * arranged for that to be done asynchronously. Anything non-zero2060 * means that we need to destroy req ourselves.2061 */2062 if (unlikely(err)) {2063 iocb_destroy(req);2064 put_reqs_available(ctx, 1);2065 }2066 return err;2067}2068 2069/* sys_io_submit:2070 * Queue the nr iocbs pointed to by iocbpp for processing. Returns2071 * the number of iocbs queued. May return -EINVAL if the aio_context2072 * specified by ctx_id is invalid, if nr is < 0, if the iocb at2073 * *iocbpp[0] is not properly initialized, if the operation specified2074 * is invalid for the file descriptor in the iocb. May fail with2075 * -EFAULT if any of the data structures point to invalid data. May2076 * fail with -EBADF if the file descriptor specified in the first2077 * iocb is invalid. May fail with -EAGAIN if insufficient resources2078 * are available to queue any iocbs. Will return 0 if nr is 0. Will2079 * fail with -ENOSYS if not implemented.2080 */2081SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,2082 struct iocb __user * __user *, iocbpp)2083{2084 struct kioctx *ctx;2085 long ret = 0;2086 int i = 0;2087 struct blk_plug plug;2088 2089 if (unlikely(nr < 0))2090 return -EINVAL;2091 2092 ctx = lookup_ioctx(ctx_id);2093 if (unlikely(!ctx)) {2094 pr_debug("EINVAL: invalid context id\n");2095 return -EINVAL;2096 }2097 2098 if (nr > ctx->nr_events)2099 nr = ctx->nr_events;2100 2101 if (nr > AIO_PLUG_THRESHOLD)2102 blk_start_plug(&plug);2103 for (i = 0; i < nr; i++) {2104 struct iocb __user *user_iocb;2105 2106 if (unlikely(get_user(user_iocb, iocbpp + i))) {2107 ret = -EFAULT;2108 break;2109 }2110 2111 ret = io_submit_one(ctx, user_iocb, false);2112 if (ret)2113 break;2114 }2115 if (nr > AIO_PLUG_THRESHOLD)2116 blk_finish_plug(&plug);2117 2118 percpu_ref_put(&ctx->users);2119 return i ? i : ret;2120}2121 2122#ifdef CONFIG_COMPAT2123COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,2124 int, nr, compat_uptr_t __user *, iocbpp)2125{2126 struct kioctx *ctx;2127 long ret = 0;2128 int i = 0;2129 struct blk_plug plug;2130 2131 if (unlikely(nr < 0))2132 return -EINVAL;2133 2134 ctx = lookup_ioctx(ctx_id);2135 if (unlikely(!ctx)) {2136 pr_debug("EINVAL: invalid context id\n");2137 return -EINVAL;2138 }2139 2140 if (nr > ctx->nr_events)2141 nr = ctx->nr_events;2142 2143 if (nr > AIO_PLUG_THRESHOLD)2144 blk_start_plug(&plug);2145 for (i = 0; i < nr; i++) {2146 compat_uptr_t user_iocb;2147 2148 if (unlikely(get_user(user_iocb, iocbpp + i))) {2149 ret = -EFAULT;2150 break;2151 }2152 2153 ret = io_submit_one(ctx, compat_ptr(user_iocb), true);2154 if (ret)2155 break;2156 }2157 if (nr > AIO_PLUG_THRESHOLD)2158 blk_finish_plug(&plug);2159 2160 percpu_ref_put(&ctx->users);2161 return i ? i : ret;2162}2163#endif2164 2165/* sys_io_cancel:2166 * Attempts to cancel an iocb previously passed to io_submit. If2167 * the operation is successfully cancelled, the resulting event is2168 * copied into the memory pointed to by result without being placed2169 * into the completion queue and 0 is returned. May fail with2170 * -EFAULT if any of the data structures pointed to are invalid.2171 * May fail with -EINVAL if aio_context specified by ctx_id is2172 * invalid. May fail with -EAGAIN if the iocb specified was not2173 * cancelled. Will fail with -ENOSYS if not implemented.2174 */2175SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,2176 struct io_event __user *, result)2177{2178 struct kioctx *ctx;2179 struct aio_kiocb *kiocb;2180 int ret = -EINVAL;2181 u32 key;2182 u64 obj = (u64)(unsigned long)iocb;2183 2184 if (unlikely(get_user(key, &iocb->aio_key)))2185 return -EFAULT;2186 if (unlikely(key != KIOCB_KEY))2187 return -EINVAL;2188 2189 ctx = lookup_ioctx(ctx_id);2190 if (unlikely(!ctx))2191 return -EINVAL;2192 2193 spin_lock_irq(&ctx->ctx_lock);2194 /* TODO: use a hash or array, this sucks. */2195 list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {2196 if (kiocb->ki_res.obj == obj) {2197 ret = kiocb->ki_cancel(&kiocb->rw);2198 list_del_init(&kiocb->ki_list);2199 break;2200 }2201 }2202 spin_unlock_irq(&ctx->ctx_lock);2203 2204 if (!ret) {2205 /*2206 * The result argument is no longer used - the io_event is2207 * always delivered via the ring buffer. -EINPROGRESS indicates2208 * cancellation is progress:2209 */2210 ret = -EINPROGRESS;2211 }2212 2213 percpu_ref_put(&ctx->users);2214 2215 return ret;2216}2217 2218static HWJS_SUSPENDS long do_io_getevents(aio_context_t ctx_id,2219 long min_nr,2220 long nr,2221 struct io_event __user *events,2222 struct timespec64 *ts)2223{2224 ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;2225 struct kioctx *ioctx = lookup_ioctx(ctx_id);2226 long ret = -EINVAL;2227 2228 if (likely(ioctx)) {2229 if (likely(min_nr <= nr && min_nr >= 0))2230 ret = read_events(ioctx, min_nr, nr, events, until);2231 percpu_ref_put(&ioctx->users);2232 }2233 2234 return ret;2235}2236 2237/* io_getevents:2238 * Attempts to read at least min_nr events and up to nr events from2239 * the completion queue for the aio_context specified by ctx_id. If2240 * it succeeds, the number of read events is returned. May fail with2241 * -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is2242 * out of range, if timeout is out of range. May fail with -EFAULT2243 * if any of the memory specified is invalid. May return 0 or2244 * < min_nr if the timeout specified by timeout has elapsed2245 * before sufficient events are available, where timeout == NULL2246 * specifies an infinite timeout. Note that the timeout pointed to by2247 * timeout is relative. Will fail with -ENOSYS if not implemented.2248 */2249#ifdef CONFIG_64BIT2250 2251SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,2252 long, min_nr,2253 long, nr,2254 struct io_event __user *, events,2255 struct __kernel_timespec __user *, timeout)2256{2257 struct timespec64 ts;2258 int ret;2259 2260 if (timeout && unlikely(get_timespec64(&ts, timeout)))2261 return -EFAULT;2262 2263 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);2264 if (!ret && signal_pending(current))2265 ret = -EINTR;2266 return ret;2267}2268 2269#endif2270 2271struct __aio_sigset {2272 const sigset_t __user *sigmask;2273 size_t sigsetsize;2274};2275 2276SYSCALL_DEFINE6(io_pgetevents,2277 aio_context_t, ctx_id,2278 long, min_nr,2279 long, nr,2280 struct io_event __user *, events,2281 struct __kernel_timespec __user *, timeout,2282 const struct __aio_sigset __user *, usig)2283{2284 struct __aio_sigset ksig = { NULL, };2285 struct timespec64 ts;2286 bool interrupted;2287 int ret;2288 2289 if (timeout && unlikely(get_timespec64(&ts, timeout)))2290 return -EFAULT;2291 2292 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))2293 return -EFAULT;2294 2295 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);2296 if (ret)2297 return ret;2298 2299 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);2300 2301 interrupted = signal_pending(current);2302 restore_saved_sigmask_unless(interrupted);2303 if (interrupted && !ret)2304 ret = -ERESTARTNOHAND;2305 2306 return ret;2307}2308 2309#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)2310 2311SYSCALL_DEFINE6(io_pgetevents_time32,2312 aio_context_t, ctx_id,2313 long, min_nr,2314 long, nr,2315 struct io_event __user *, events,2316 struct old_timespec32 __user *, timeout,2317 const struct __aio_sigset __user *, usig)2318{2319 struct __aio_sigset ksig = { NULL, };2320 struct timespec64 ts;2321 bool interrupted;2322 int ret;2323 2324 if (timeout && unlikely(get_old_timespec32(&ts, timeout)))2325 return -EFAULT;2326 2327 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))2328 return -EFAULT;2329 2330 2331 ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);2332 if (ret)2333 return ret;2334 2335 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);2336 2337 interrupted = signal_pending(current);2338 restore_saved_sigmask_unless(interrupted);2339 if (interrupted && !ret)2340 ret = -ERESTARTNOHAND;2341 2342 return ret;2343}2344 2345#endif2346 2347#if defined(CONFIG_COMPAT_32BIT_TIME)2348 2349SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,2350 __s32, min_nr,2351 __s32, nr,2352 struct io_event __user *, events,2353 struct old_timespec32 __user *, timeout)2354{2355 struct timespec64 t;2356 int ret;2357 2358 if (timeout && get_old_timespec32(&t, timeout))2359 return -EFAULT;2360 2361 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);2362 if (!ret && signal_pending(current))2363 ret = -EINTR;2364 return ret;2365}2366 2367#endif2368 2369#ifdef CONFIG_COMPAT2370 2371struct __compat_aio_sigset {2372 compat_uptr_t sigmask;2373 compat_size_t sigsetsize;2374};2375 2376#if defined(CONFIG_COMPAT_32BIT_TIME)2377 2378COMPAT_SYSCALL_DEFINE6(io_pgetevents,2379 compat_aio_context_t, ctx_id,2380 compat_long_t, min_nr,2381 compat_long_t, nr,2382 struct io_event __user *, events,2383 struct old_timespec32 __user *, timeout,2384 const struct __compat_aio_sigset __user *, usig)2385{2386 struct __compat_aio_sigset ksig = { 0, };2387 struct timespec64 t;2388 bool interrupted;2389 int ret;2390 2391 if (timeout && get_old_timespec32(&t, timeout))2392 return -EFAULT;2393 2394 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))2395 return -EFAULT;2396 2397 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);2398 if (ret)2399 return ret;2400 2401 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);2402 2403 interrupted = signal_pending(current);2404 restore_saved_sigmask_unless(interrupted);2405 if (interrupted && !ret)2406 ret = -ERESTARTNOHAND;2407 2408 return ret;2409}2410 2411#endif2412 2413COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,2414 compat_aio_context_t, ctx_id,2415 compat_long_t, min_nr,2416 compat_long_t, nr,2417 struct io_event __user *, events,2418 struct __kernel_timespec __user *, timeout,2419 const struct __compat_aio_sigset __user *, usig)2420{2421 struct __compat_aio_sigset ksig = { 0, };2422 struct timespec64 t;2423 bool interrupted;2424 int ret;2425 2426 if (timeout && get_timespec64(&t, timeout))2427 return -EFAULT;2428 2429 if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))2430 return -EFAULT;2431 2432 ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);2433 if (ret)2434 return ret;2435 2436 ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);2437 2438 interrupted = signal_pending(current);2439 restore_saved_sigmask_unless(interrupted);2440 if (interrupted && !ret)2441 ret = -ERESTARTNOHAND;2442 2443 return ret;2444}2445#endif2446