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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  *  An async IO implementation for Linux
  *  Written by Benjamin LaHaise <bcrl@kvack.org>
  *
  *  Implements an efficient asynchronous io interface.
  *
  *  Copyright 2000, 2001, 2002 Red Hat, Inc.  All Rights Reserved.
  *  Copyright 2018 Christoph Hellwig.
  *
  *  See ../COPYING for licensing terms.
  */
 #define pr_fmt(fmt) "%s: " fmt, __func__
 
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/time.h>
 #include <linux/aio_abi.h>
 #include <linux/export.h>
 #include <linux/syscalls.h>
 #include <linux/backing-dev.h>
 #include <linux/refcount.h>
 #include <linux/uio.h>
 
 #include <linux/sched/signal.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/timer.h>
 #include <linux/aio.h>
 #include <linux/highmem.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>
 #include <linux/eventfd.h>
 #include <linux/blkdev.h>
 #include <linux/compat.h>
 #include <linux/migrate.h>
 #include <linux/ramfs.h>
 #include <linux/percpu-refcount.h>
 #include <linux/mount.h>
 #include <linux/pseudo_fs.h>
 
 #include <linux/uaccess.h>
 #include <linux/nospec.h>
 
 #include "internal.h"
 
 #define KIOCB_KEY       0
 
 #define AIO_RING_MAGIC          0xa10a10a1
 #define AIO_RING_COMPAT_FEATURES    1
 #define AIO_RING_INCOMPAT_FEATURES  0
 struct aio_ring {
     unsigned    id; /* kernel internal index number */
     unsigned    nr; /* number of io_events */
     unsigned    head;   /* Written to by userland or under ring_lock
                  * mutex by aio_read_events_ring(). */
     unsigned    tail;
 
     unsigned    magic;
     unsigned    compat_features;
     unsigned    incompat_features;
     unsigned    header_length;  /* size of aio_ring */
 
 
     struct io_event     io_events[];
 }; /* 128 bytes + ring size */
 
 /*
  * Plugging is meant to work with larger batches of IOs. If we don't
  * have more than the below, then don't bother setting up a plug.
  */
 #define AIO_PLUG_THRESHOLD  2
 
 #define AIO_RING_PAGES  8
 
 struct kioctx_table {
     struct rcu_head     rcu;
     unsigned        nr;
     struct kioctx __rcu *table[];
 };
 
 struct kioctx_cpu {
     unsigned        reqs_available;
 };
 
 struct ctx_rq_wait {
     struct completion comp;
     atomic_t count;
 };
 
 struct kioctx {
     struct percpu_ref   users;
     atomic_t        dead;
 
     struct percpu_ref   reqs;
 
     unsigned long       user_id;
 
     struct __percpu kioctx_cpu *cpu;
 
     /*
      * For percpu reqs_available, number of slots we move to/from global
      * counter at a time:
      */
     unsigned        req_batch;
     /*
      * This is what userspace passed to io_setup(), it's not used for
      * anything but counting against the global max_reqs quota.
      *
      * The real limit is nr_events - 1, which will be larger (see
      * aio_setup_ring())
      */
     unsigned        max_reqs;
 
     /* Size of ringbuffer, in units of struct io_event */
     unsigned        nr_events;
 
     unsigned long       mmap_base;
     unsigned long       mmap_size;
 
     struct page     **ring_pages;
     long            nr_pages;
 
     struct rcu_work     free_rwork; /* see free_ioctx() */
 
     /*
      * signals when all in-flight requests are done
      */
     struct ctx_rq_wait  *rq_wait;
 
     struct {
         /*
          * This counts the number of available slots in the ringbuffer,
          * so we avoid overflowing it: it's decremented (if positive)
          * when allocating a kiocb and incremented when the resulting
          * io_event is pulled off the ringbuffer.
          *
          * We batch accesses to it with a percpu version.
          */
         atomic_t    reqs_available;
     } ____cacheline_aligned_in_smp;
 
     struct {
         spinlock_t  ctx_lock;
         struct list_head active_reqs;   /* used for cancellation */
     } ____cacheline_aligned_in_smp;
 
     struct {
         struct mutex    ring_lock;
         wait_queue_head_t wait;
     } ____cacheline_aligned_in_smp;
 
     struct {
         unsigned    tail;
         unsigned    completed_events;
         spinlock_t  completion_lock;
     } ____cacheline_aligned_in_smp;
 
     struct page     *internal_pages[AIO_RING_PAGES];
     struct file     *aio_ring_file;
 
     unsigned        id;
 };
 
 /*
  * First field must be the file pointer in all the
  * iocb unions! See also 'struct kiocb' in <linux/fs.h>
  */
 struct fsync_iocb {
     struct file     *file;
     struct work_struct  work;
     bool            datasync;
     struct cred     *creds;
 };
 
 struct poll_iocb {
     struct file     *file;
     struct wait_queue_head  *head;
     __poll_t        events;
     bool            cancelled;
     bool            work_scheduled;
     bool            work_need_resched;
     struct wait_queue_entry wait;
     struct work_struct  work;
 };
 
 /*
  * NOTE! Each of the iocb union members has the file pointer
  * as the first entry in their struct definition. So you can
  * access the file pointer through any of the sub-structs,
  * or directly as just 'ki_filp' in this struct.
  */
 struct aio_kiocb {
     union {
         struct file     *ki_filp;
         struct kiocb        rw;
         struct fsync_iocb   fsync;
         struct poll_iocb    poll;
     };
 
     struct kioctx       *ki_ctx;
     kiocb_cancel_fn     *ki_cancel;
 
     struct io_event     ki_res;
 
     struct list_head    ki_list;    /* the aio core uses this
                          * for cancellation */
     refcount_t      ki_refcnt;
 
     /*
      * If the aio_resfd field of the userspace iocb is not zero,
      * this is the underlying eventfd context to deliver events to.
      */
     struct eventfd_ctx  *ki_eventfd;
 };
 
 /*------ sysctl variables----*/
 static DEFINE_SPINLOCK(aio_nr_lock);
 static unsigned long aio_nr;        /* current system wide number of aio requests */
 static unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
 /*----end sysctl variables---*/
 #ifdef CONFIG_SYSCTL
 static struct ctl_table aio_sysctls[] = {
     {
         .procname   = "aio-nr",
         .data       = &aio_nr,
         .maxlen     = sizeof(aio_nr),
         .mode       = 0444,
         .proc_handler   = proc_doulongvec_minmax,
     },
     {
         .procname   = "aio-max-nr",
         .data       = &aio_max_nr,
         .maxlen     = sizeof(aio_max_nr),
         .mode       = 0644,
         .proc_handler   = proc_doulongvec_minmax,
     },
     {}
 };
 
 static void __init aio_sysctl_init(void)
 {
     register_sysctl_init("fs", aio_sysctls);
 }
 #else
 #define aio_sysctl_init() do { } while (0)
 #endif
 
 static struct kmem_cache    *kiocb_cachep;
 static struct kmem_cache    *kioctx_cachep;
 
 static struct vfsmount *aio_mnt;
 
 static const struct file_operations aio_ring_fops;
 static const struct address_space_operations aio_ctx_aops;
 
 static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 {
     struct file *file;
     struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
     if (IS_ERR(inode))
         return ERR_CAST(inode);
 
     inode->i_mapping->a_ops = &aio_ctx_aops;
     inode->i_mapping->private_data = ctx;
     inode->i_size = PAGE_SIZE * nr_pages;
 
     file = alloc_file_pseudo(inode, aio_mnt, "[aio]",
                 O_RDWR, &aio_ring_fops);
     if (IS_ERR(file))
         iput(inode);
     return file;
 }
 
 static int aio_init_fs_context(struct fs_context *fc)
 {
     if (!init_pseudo(fc, AIO_RING_MAGIC))
         return -ENOMEM;
     fc->s_iflags |= SB_I_NOEXEC;
     return 0;
 }
 
 /* aio_setup
  *  Creates the slab caches used by the aio routines, panic on
  *  failure as this is done early during the boot sequence.
  */
 static int __init aio_setup(void)
 {
     static struct file_system_type aio_fs = {
         .name       = "aio",
         .init_fs_context = aio_init_fs_context,
         .kill_sb    = kill_anon_super,
     };
     aio_mnt = kern_mount(&aio_fs);
     if (IS_ERR(aio_mnt))
         panic("Failed to create aio fs mount.");
 
     kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
     kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
     aio_sysctl_init();
     return 0;
 }
 __initcall(aio_setup);
 
 static void put_aio_ring_file(struct kioctx *ctx)
 {
     struct file *aio_ring_file = ctx->aio_ring_file;
     struct address_space *i_mapping;
 
     if (aio_ring_file) {
         truncate_setsize(file_inode(aio_ring_file), 0);
 
         /* Prevent further access to the kioctx from migratepages */
         i_mapping = aio_ring_file->f_mapping;
         spin_lock(&i_mapping->private_lock);
         i_mapping->private_data = NULL;
         ctx->aio_ring_file = NULL;
         spin_unlock(&i_mapping->private_lock);
 
         fput(aio_ring_file);
     }
 }
 
 static void aio_free_ring(struct kioctx *ctx)
 {
     int i;
 
     /* Disconnect the kiotx from the ring file.  This prevents future
      * accesses to the kioctx from page migration.
      */
     put_aio_ring_file(ctx);
 
     for (i = 0; i < ctx->nr_pages; i++) {
         struct page *page;
         pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
                 page_count(ctx->ring_pages[i]));
         page = ctx->ring_pages[i];
         if (!page)
             continue;
         ctx->ring_pages[i] = NULL;
         put_page(page);
     }
 
     if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
         kfree(ctx->ring_pages);
         ctx->ring_pages = NULL;
     }
 }
 
 static int aio_ring_mremap(struct vm_area_struct *vma)
 {
     struct file *file = vma->vm_file;
     struct mm_struct *mm = vma->vm_mm;
     struct kioctx_table *table;
     int i, res = -EINVAL;
 
     spin_lock(&mm->ioctx_lock);
     rcu_read_lock();
     table = rcu_dereference(mm->ioctx_table);
     for (i = 0; i < table->nr; i++) {
         struct kioctx *ctx;
 
         ctx = rcu_dereference(table->table[i]);
         if (ctx && ctx->aio_ring_file == file) {
             if (!atomic_read(&ctx->dead)) {
                 ctx->user_id = ctx->mmap_base = vma->vm_start;
                 res = 0;
             }
             break;
         }
     }
 
     rcu_read_unlock();
     spin_unlock(&mm->ioctx_lock);
     return res;
 }
 
 static const struct vm_operations_struct aio_ring_vm_ops = {
     .mremap     = aio_ring_mremap,
 #if IS_ENABLED(CONFIG_MMU)
     .fault      = filemap_fault,
     .map_pages  = filemap_map_pages,
     .page_mkwrite   = filemap_page_mkwrite,
 #endif
 };
 
 static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
 {
     vma->vm_flags |= VM_DONTEXPAND;
     vma->vm_ops = &aio_ring_vm_ops;
     return 0;
 }
 
 static const struct file_operations aio_ring_fops = {
     .mmap = aio_ring_mmap,
 };
 
 #if IS_ENABLED(CONFIG_MIGRATION)
 static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
             struct folio *src, enum migrate_mode mode)
 {
     struct kioctx *ctx;
     unsigned long flags;
     pgoff_t idx;
     int rc;
 
     /*
      * We cannot support the _NO_COPY case here, because copy needs to
      * happen under the ctx->completion_lock. That does not work with the
      * migration workflow of MIGRATE_SYNC_NO_COPY.
      */
     if (mode == MIGRATE_SYNC_NO_COPY)
         return -EINVAL;
 
     rc = 0;
 
     /* mapping->private_lock here protects against the kioctx teardown.  */
     spin_lock(&mapping->private_lock);
     ctx = mapping->private_data;
     if (!ctx) {
         rc = -EINVAL;
         goto out;
     }
 
     /* The ring_lock mutex.  The prevents aio_read_events() from writing
      * to the ring's head, and prevents page migration from mucking in
      * a partially initialized kiotx.
      */
     if (!mutex_trylock(&ctx->ring_lock)) {
         rc = -EAGAIN;
         goto out;
     }
 
     idx = src->index;
     if (idx < (pgoff_t)ctx->nr_pages) {
         /* Make sure the old folio hasn't already been changed */
         if (ctx->ring_pages[idx] != &src->page)
             rc = -EAGAIN;
     } else
         rc = -EINVAL;
 
     if (rc != 0)
         goto out_unlock;
 
     /* Writeback must be complete */
     BUG_ON(folio_test_writeback(src));
     folio_get(dst);
 
     rc = folio_migrate_mapping(mapping, dst, src, 1);
     if (rc != MIGRATEPAGE_SUCCESS) {
         folio_put(dst);
         goto out_unlock;
     }
 
     /* Take completion_lock to prevent other writes to the ring buffer
      * while the old folio is copied to the new.  This prevents new
      * events from being lost.
      */
     spin_lock_irqsave(&ctx->completion_lock, flags);
     folio_migrate_copy(dst, src);
     BUG_ON(ctx->ring_pages[idx] != &src->page);
     ctx->ring_pages[idx] = &dst->page;
     spin_unlock_irqrestore(&ctx->completion_lock, flags);
 
     /* The old folio is no longer accessible. */
     folio_put(src);
 
 out_unlock:
     mutex_unlock(&ctx->ring_lock);
 out:
     spin_unlock(&mapping->private_lock);
     return rc;
 }
 #else
 #define aio_migrate_folio NULL
 #endif
 
 static const struct address_space_operations aio_ctx_aops = {
     .dirty_folio    = noop_dirty_folio,
     .migrate_folio  = aio_migrate_folio,
 };
 
 static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
 {
     struct aio_ring *ring;
     struct mm_struct *mm = current->mm;
     unsigned long size, unused;
     int nr_pages;
     int i;
     struct file *file;
 
     /* Compensate for the ring buffer's head/tail overlap entry */
     nr_events += 2; /* 1 is required, 2 for good luck */
 
     size = sizeof(struct aio_ring);
     size += sizeof(struct io_event) * nr_events;
 
     nr_pages = PFN_UP(size);
     if (nr_pages < 0)
         return -EINVAL;
 
     file = aio_private_file(ctx, nr_pages);
     if (IS_ERR(file)) {
         ctx->aio_ring_file = NULL;
         return -ENOMEM;
     }
 
     ctx->aio_ring_file = file;
     nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
             / sizeof(struct io_event);
 
     ctx->ring_pages = ctx->internal_pages;
     if (nr_pages > AIO_RING_PAGES) {
         ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
                       GFP_KERNEL);
         if (!ctx->ring_pages) {
             put_aio_ring_file(ctx);
             return -ENOMEM;
         }
     }
 
     for (i = 0; i < nr_pages; i++) {
         struct page *page;
         page = find_or_create_page(file->f_mapping,
                        i, GFP_HIGHUSER | __GFP_ZERO);
         if (!page)
             break;
         pr_debug("pid(%d) page[%d]->count=%d\n",
              current->pid, i, page_count(page));
         SetPageUptodate(page);
         unlock_page(page);
 
         ctx->ring_pages[i] = page;
     }
     ctx->nr_pages = i;
 
     if (unlikely(i != nr_pages)) {
         aio_free_ring(ctx);
         return -ENOMEM;
     }
 
     ctx->mmap_size = nr_pages * PAGE_SIZE;
     pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
 
     if (mmap_write_lock_killable(mm)) {
         ctx->mmap_size = 0;
         aio_free_ring(ctx);
         return -EINTR;
     }
 
     ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
                  PROT_READ | PROT_WRITE,
                  MAP_SHARED, 0, &unused, NULL);
     mmap_write_unlock(mm);
     if (IS_ERR((void *)ctx->mmap_base)) {
         ctx->mmap_size = 0;
         aio_free_ring(ctx);
         return -ENOMEM;
     }
 
     pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
 
     ctx->user_id = ctx->mmap_base;
     ctx->nr_events = nr_events; /* trusted copy */
 
     ring = kmap_atomic(ctx->ring_pages[0]);
     ring->nr = nr_events;   /* user copy */
     ring->id = ~0U;
     ring->head = ring->tail = 0;
     ring->magic = AIO_RING_MAGIC;
     ring->compat_features = AIO_RING_COMPAT_FEATURES;
     ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
     ring->header_length = sizeof(struct aio_ring);
     kunmap_atomic(ring);
     flush_dcache_page(ctx->ring_pages[0]);
 
     return 0;
 }
 
 #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
 #define AIO_EVENTS_FIRST_PAGE   ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
 #define AIO_EVENTS_OFFSET   (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
 
 void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
 {
     struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
     struct kioctx *ctx = req->ki_ctx;
     unsigned long flags;
 
     if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
         return;
 
     spin_lock_irqsave(&ctx->ctx_lock, flags);
     list_add_tail(&req->ki_list, &ctx->active_reqs);
     req->ki_cancel = cancel;
     spin_unlock_irqrestore(&ctx->ctx_lock, flags);
 }
 EXPORT_SYMBOL(kiocb_set_cancel_fn);
 
 /*
  * free_ioctx() should be RCU delayed to synchronize against the RCU
  * protected lookup_ioctx() and also needs process context to call
  * aio_free_ring().  Use rcu_work.
  */
 static void free_ioctx(struct work_struct *work)
 {
     struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx,
                       free_rwork);
     pr_debug("freeing %p\n", ctx);
 
     aio_free_ring(ctx);
     free_percpu(ctx->cpu);
     percpu_ref_exit(&ctx->reqs);
     percpu_ref_exit(&ctx->users);
     kmem_cache_free(kioctx_cachep, ctx);
 }
 
 static void free_ioctx_reqs(struct percpu_ref *ref)
 {
     struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
 
     /* At this point we know that there are no any in-flight requests */
     if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
         complete(&ctx->rq_wait->comp);
 
     /* Synchronize against RCU protected table->table[] dereferences */
     INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
     queue_rcu_work(system_wq, &ctx->free_rwork);
 }
 
 /*
  * When this function runs, the kioctx has been removed from the "hash table"
  * and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
  * now it's safe to cancel any that need to be.
  */
 static void free_ioctx_users(struct percpu_ref *ref)
 {
     struct kioctx *ctx = container_of(ref, struct kioctx, users);
     struct aio_kiocb *req;
 
     spin_lock_irq(&ctx->ctx_lock);
 
     while (!list_empty(&ctx->active_reqs)) {
         req = list_first_entry(&ctx->active_reqs,
                        struct aio_kiocb, ki_list);
         req->ki_cancel(&req->rw);
         list_del_init(&req->ki_list);
     }
 
     spin_unlock_irq(&ctx->ctx_lock);
 
     percpu_ref_kill(&ctx->reqs);
     percpu_ref_put(&ctx->reqs);
 }
 
 static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
 {
     unsigned i, new_nr;
     struct kioctx_table *table, *old;
     struct aio_ring *ring;
 
     spin_lock(&mm->ioctx_lock);
     table = rcu_dereference_raw(mm->ioctx_table);
 
     while (1) {
         if (table)
             for (i = 0; i < table->nr; i++)
                 if (!rcu_access_pointer(table->table[i])) {
                     ctx->id = i;
                     rcu_assign_pointer(table->table[i], ctx);
                     spin_unlock(&mm->ioctx_lock);
 
                     /* While kioctx setup is in progress,
                      * we are protected from page migration
                      * changes ring_pages by ->ring_lock.
                      */
                     ring = kmap_atomic(ctx->ring_pages[0]);
                     ring->id = ctx->id;
                     kunmap_atomic(ring);
                     return 0;
                 }
 
         new_nr = (table ? table->nr : 1) * 4;
         spin_unlock(&mm->ioctx_lock);
 
         table = kzalloc(struct_size(table, table, new_nr), GFP_KERNEL);
         if (!table)
             return -ENOMEM;
 
         table->nr = new_nr;
 
         spin_lock(&mm->ioctx_lock);
         old = rcu_dereference_raw(mm->ioctx_table);
 
         if (!old) {
             rcu_assign_pointer(mm->ioctx_table, table);
         } else if (table->nr > old->nr) {
             memcpy(table->table, old->table,
                    old->nr * sizeof(struct kioctx *));
 
             rcu_assign_pointer(mm->ioctx_table, table);
             kfree_rcu(old, rcu);
         } else {
             kfree(table);
             table = old;
         }
     }
 }
 
 static void aio_nr_sub(unsigned nr)
 {
     spin_lock(&aio_nr_lock);
     if (WARN_ON(aio_nr - nr > aio_nr))
         aio_nr = 0;
     else
         aio_nr -= nr;
     spin_unlock(&aio_nr_lock);
 }
 
 /* ioctx_alloc
  *  Allocates and initializes an ioctx.  Returns an ERR_PTR if it failed.
  */
 static struct kioctx *ioctx_alloc(unsigned nr_events)
 {
     struct mm_struct *mm = current->mm;
     struct kioctx *ctx;
     int err = -ENOMEM;
 
     /*
      * Store the original nr_events -- what userspace passed to io_setup(),
      * for counting against the global limit -- before it changes.
      */
     unsigned int max_reqs = nr_events;
 
     /*
      * We keep track of the number of available ringbuffer slots, to prevent
      * overflow (reqs_available), and we also use percpu counters for this.
      *
      * So since up to half the slots might be on other cpu's percpu counters
      * and unavailable, double nr_events so userspace sees what they
      * expected: additionally, we move req_batch slots to/from percpu
      * counters at a time, so make sure that isn't 0:
      */
     nr_events = max(nr_events, num_possible_cpus() * 4);
     nr_events *= 2;
 
     /* Prevent overflows */
     if (nr_events > (0x10000000U / sizeof(struct io_event))) {
         pr_debug("ENOMEM: nr_events too high\n");
         return ERR_PTR(-EINVAL);
     }
 
     if (!nr_events || (unsigned long)max_reqs > aio_max_nr)
         return ERR_PTR(-EAGAIN);
 
     ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
     if (!ctx)
         return ERR_PTR(-ENOMEM);
 
     ctx->max_reqs = max_reqs;
 
     spin_lock_init(&ctx->ctx_lock);
     spin_lock_init(&ctx->completion_lock);
     mutex_init(&ctx->ring_lock);
     /* Protect against page migration throughout kiotx setup by keeping
      * the ring_lock mutex held until setup is complete. */
     mutex_lock(&ctx->ring_lock);
     init_waitqueue_head(&ctx->wait);
 
     INIT_LIST_HEAD(&ctx->active_reqs);
 
     if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
         goto err;
 
     if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
         goto err;
 
     ctx->cpu = alloc_percpu(struct kioctx_cpu);
     if (!ctx->cpu)
         goto err;
 
     err = aio_setup_ring(ctx, nr_events);
     if (err < 0)
         goto err;
 
     atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
     ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
     if (ctx->req_batch < 1)
         ctx->req_batch = 1;
 
     /* limit the number of system wide aios */
     spin_lock(&aio_nr_lock);
     if (aio_nr + ctx->max_reqs > aio_max_nr ||
         aio_nr + ctx->max_reqs < aio_nr) {
         spin_unlock(&aio_nr_lock);
         err = -EAGAIN;
         goto err_ctx;
     }
     aio_nr += ctx->max_reqs;
     spin_unlock(&aio_nr_lock);
 
     percpu_ref_get(&ctx->users);    /* io_setup() will drop this ref */
     percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
 
     err = ioctx_add_table(ctx, mm);
     if (err)
         goto err_cleanup;
 
     /* Release the ring_lock mutex now that all setup is complete. */
     mutex_unlock(&ctx->ring_lock);
 
     pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
          ctx, ctx->user_id, mm, ctx->nr_events);
     return ctx;
 
 err_cleanup:
     aio_nr_sub(ctx->max_reqs);
 err_ctx:
     atomic_set(&ctx->dead, 1);
     if (ctx->mmap_size)
         vm_munmap(ctx->mmap_base, ctx->mmap_size);
     aio_free_ring(ctx);
 err:
     mutex_unlock(&ctx->ring_lock);
     free_percpu(ctx->cpu);
     percpu_ref_exit(&ctx->reqs);
     percpu_ref_exit(&ctx->users);
     kmem_cache_free(kioctx_cachep, ctx);
     pr_debug("error allocating ioctx %d\n", err);
     return ERR_PTR(err);
 }
 
 /* kill_ioctx
  *  Cancels all outstanding aio requests on an aio context.  Used
  *  when the processes owning a context have all exited to encourage
  *  the rapid destruction of the kioctx.
  */
 static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
               struct ctx_rq_wait *wait)
 {
     struct kioctx_table *table;
 
     spin_lock(&mm->ioctx_lock);
     if (atomic_xchg(&ctx->dead, 1)) {
         spin_unlock(&mm->ioctx_lock);
         return -EINVAL;
     }
 
     table = rcu_dereference_raw(mm->ioctx_table);
     WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id]));
     RCU_INIT_POINTER(table->table[ctx->id], NULL);
     spin_unlock(&mm->ioctx_lock);
 
     /* free_ioctx_reqs() will do the necessary RCU synchronization */
     wake_up_all(&ctx->wait);
 
     /*
      * It'd be more correct to do this in free_ioctx(), after all
      * the outstanding kiocbs have finished - but by then io_destroy
      * has already returned, so io_setup() could potentially return
      * -EAGAIN with no ioctxs actually in use (as far as userspace
      *  could tell).
      */
     aio_nr_sub(ctx->max_reqs);
 
     if (ctx->mmap_size)
         vm_munmap(ctx->mmap_base, ctx->mmap_size);
 
     ctx->rq_wait = wait;
     percpu_ref_kill(&ctx->users);
     return 0;
 }
 
 /*
  * exit_aio: called when the last user of mm goes away.  At this point, there is
  * no way for any new requests to be submited or any of the io_* syscalls to be
  * called on the context.
  *
  * There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
  * them.
  */
 void exit_aio(struct mm_struct *mm)
 {
     struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
     struct ctx_rq_wait wait;
     int i, skipped;
 
     if (!table)
         return;
 
     atomic_set(&wait.count, table->nr);
     init_completion(&wait.comp);
 
     skipped = 0;
     for (i = 0; i < table->nr; ++i) {
         struct kioctx *ctx =
             rcu_dereference_protected(table->table[i], true);
 
         if (!ctx) {
             skipped++;
             continue;
         }
 
         /*
          * We don't need to bother with munmap() here - exit_mmap(mm)
          * is coming and it'll unmap everything. And we simply can't,
          * this is not necessarily our ->mm.
          * Since kill_ioctx() uses non-zero ->mmap_size as indicator
          * that it needs to unmap the area, just set it to 0.
          */
         ctx->mmap_size = 0;
         kill_ioctx(mm, ctx, &wait);
     }
 
     if (!atomic_sub_and_test(skipped, &wait.count)) {
         /* Wait until all IO for the context are done. */
         wait_for_completion(&wait.comp);
     }
 
     RCU_INIT_POINTER(mm->ioctx_table, NULL);
     kfree(table);
 }
 
 static void put_reqs_available(struct kioctx *ctx, unsigned nr)
 {
     struct kioctx_cpu *kcpu;
     unsigned long flags;
 
     local_irq_save(flags);
     kcpu = this_cpu_ptr(ctx->cpu);
     kcpu->reqs_available += nr;
 
     while (kcpu->reqs_available >= ctx->req_batch * 2) {
         kcpu->reqs_available -= ctx->req_batch;
         atomic_add(ctx->req_batch, &ctx->reqs_available);
     }
 
     local_irq_restore(flags);
 }
 
 static bool __get_reqs_available(struct kioctx *ctx)
 {
     struct kioctx_cpu *kcpu;
     bool ret = false;
     unsigned long flags;
 
     local_irq_save(flags);
     kcpu = this_cpu_ptr(ctx->cpu);
     if (!kcpu->reqs_available) {
         int old, avail = atomic_read(&ctx->reqs_available);
 
         do {
             if (avail < ctx->req_batch)
                 goto out;
 
             old = avail;
             avail = atomic_cmpxchg(&ctx->reqs_available,
                            avail, avail - ctx->req_batch);
         } while (avail != old);
 
         kcpu->reqs_available += ctx->req_batch;
     }
 
     ret = true;
     kcpu->reqs_available--;
 out:
     local_irq_restore(flags);
     return ret;
 }
 
 /* refill_reqs_available
  *  Updates the reqs_available reference counts used for tracking the
  *  number of free slots in the completion ring.  This can be called
  *  from aio_complete() (to optimistically update reqs_available) or
  *  from aio_get_req() (the we're out of events case).  It must be
  *  called holding ctx->completion_lock.
  */
 static void refill_reqs_available(struct kioctx *ctx, unsigned head,
                                   unsigned tail)
 {
     unsigned events_in_ring, completed;
 
     /* Clamp head since userland can write to it. */
     head %= ctx->nr_events;
     if (head <= tail)
         events_in_ring = tail - head;
     else
         events_in_ring = ctx->nr_events - (head - tail);
 
     completed = ctx->completed_events;
     if (events_in_ring < completed)
         completed -= events_in_ring;
     else
         completed = 0;
 
     if (!completed)
         return;
 
     ctx->completed_events -= completed;
     put_reqs_available(ctx, completed);
 }
 
 /* user_refill_reqs_available
  *  Called to refill reqs_available when aio_get_req() encounters an
  *  out of space in the completion ring.
  */
 static void user_refill_reqs_available(struct kioctx *ctx)
 {
     spin_lock_irq(&ctx->completion_lock);
     if (ctx->completed_events) {
         struct aio_ring *ring;
         unsigned head;
 
         /* Access of ring->head may race with aio_read_events_ring()
          * here, but that's okay since whether we read the old version
          * or the new version, and either will be valid.  The important
          * part is that head cannot pass tail since we prevent
          * aio_complete() from updating tail by holding
          * ctx->completion_lock.  Even if head is invalid, the check
          * against ctx->completed_events below will make sure we do the
          * safe/right thing.
          */
         ring = kmap_atomic(ctx->ring_pages[0]);
         head = ring->head;
         kunmap_atomic(ring);
 
         refill_reqs_available(ctx, head, ctx->tail);
     }
 
     spin_unlock_irq(&ctx->completion_lock);
 }
 
 static bool get_reqs_available(struct kioctx *ctx)
 {
     if (__get_reqs_available(ctx))
         return true;
     user_refill_reqs_available(ctx);
     return __get_reqs_available(ctx);
 }
 
 /* aio_get_req
  *  Allocate a slot for an aio request.
  * Returns NULL if no requests are free.
  *
  * The refcount is initialized to 2 - one for the async op completion,
  * one for the synchronous code that does this.
  */
 static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
 {
     struct aio_kiocb *req;
 
     req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
     if (unlikely(!req))
         return NULL;
 
     if (unlikely(!get_reqs_available(ctx))) {
         kmem_cache_free(kiocb_cachep, req);
         return NULL;
     }
 
     percpu_ref_get(&ctx->reqs);
     req->ki_ctx = ctx;
     INIT_LIST_HEAD(&req->ki_list);
     refcount_set(&req->ki_refcnt, 2);
     req->ki_eventfd = NULL;
     return req;
 }
 
 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
 {
     struct aio_ring __user *ring  = (void __user *)ctx_id;
     struct mm_struct *mm = current->mm;
     struct kioctx *ctx, *ret = NULL;
     struct kioctx_table *table;
     unsigned id;
 
     if (get_user(id, &ring->id))
         return NULL;
 
     rcu_read_lock();
     table = rcu_dereference(mm->ioctx_table);
 
     if (!table || id >= table->nr)
         goto out;
 
     id = array_index_nospec(id, table->nr);
     ctx = rcu_dereference(table->table[id]);
     if (ctx && ctx->user_id == ctx_id) {
         if (percpu_ref_tryget_live(&ctx->users))
             ret = ctx;
     }
 out:
     rcu_read_unlock();
     return ret;
 }
 
 static inline void iocb_destroy(struct aio_kiocb *iocb)
 {
     if (iocb->ki_eventfd)
         eventfd_ctx_put(iocb->ki_eventfd);
     if (iocb->ki_filp)
         fput(iocb->ki_filp);
     percpu_ref_put(&iocb->ki_ctx->reqs);
     kmem_cache_free(kiocb_cachep, iocb);
 }
 
 /* aio_complete
  *  Called when the io request on the given iocb is complete.
  */
 static void aio_complete(struct aio_kiocb *iocb)
 {
     struct kioctx   *ctx = iocb->ki_ctx;
     struct aio_ring *ring;
     struct io_event *ev_page, *event;
     unsigned tail, pos, head;
     unsigned long   flags;
 
     /*
      * Add a completion event to the ring buffer. Must be done holding
      * ctx->completion_lock to prevent other code from messing with the tail
      * pointer since we might be called from irq context.
      */
     spin_lock_irqsave(&ctx->completion_lock, flags);
 
     tail = ctx->tail;
     pos = tail + AIO_EVENTS_OFFSET;
 
     if (++tail >= ctx->nr_events)
         tail = 0;
 
     ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
     event = ev_page + pos % AIO_EVENTS_PER_PAGE;
 
     *event = iocb->ki_res;
 
     kunmap_atomic(ev_page);
     flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
 
     pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb,
          (void __user *)(unsigned long)iocb->ki_res.obj,
          iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2);
 
     /* after flagging the request as done, we
      * must never even look at it again
      */
     smp_wmb();  /* make event visible before updating tail */
 
     ctx->tail = tail;
 
     ring = kmap_atomic(ctx->ring_pages[0]);
     head = ring->head;
     ring->tail = tail;
     kunmap_atomic(ring);
     flush_dcache_page(ctx->ring_pages[0]);
 
     ctx->completed_events++;
     if (ctx->completed_events > 1)
         refill_reqs_available(ctx, head, tail);
     spin_unlock_irqrestore(&ctx->completion_lock, flags);
 
     pr_debug("added to ring %p at [%u]\n", iocb, tail);
 
     /*
      * Check if the user asked us to deliver the result through an
      * eventfd. The eventfd_signal() function is safe to be called
      * from IRQ context.
      */
     if (iocb->ki_eventfd)
         eventfd_signal(iocb->ki_eventfd, 1);
 
     /*
      * We have to order our ring_info tail store above and test
      * of the wait list below outside the wait lock.  This is
      * like in wake_up_bit() where clearing a bit has to be
      * ordered with the unlocked test.
      */
     smp_mb();
 
     if (waitqueue_active(&ctx->wait))
         wake_up(&ctx->wait);
 }
 
 static inline void iocb_put(struct aio_kiocb *iocb)
 {
     if (refcount_dec_and_test(&iocb->ki_refcnt)) {
         aio_complete(iocb);
         iocb_destroy(iocb);
     }
 }
 
 /* aio_read_events_ring
  *  Pull an event off of the ioctx's event ring.  Returns the number of
  *  events fetched
  */
 static long aio_read_events_ring(struct kioctx *ctx,
                  struct io_event __user *event, long nr)
 {
     struct aio_ring *ring;
     unsigned head, tail, pos;
     long ret = 0;
     int copy_ret;
 
     /*
      * The mutex can block and wake us up and that will cause
      * wait_event_interruptible_hrtimeout() to schedule without sleeping
      * and repeat. This should be rare enough that it doesn't cause
      * peformance issues. See the comment in read_events() for more detail.
      */
     sched_annotate_sleep();
     mutex_lock(&ctx->ring_lock);
 
     /* Access to ->ring_pages here is protected by ctx->ring_lock. */
     ring = kmap_atomic(ctx->ring_pages[0]);
     head = ring->head;
     tail = ring->tail;
     kunmap_atomic(ring);
 
     /*
      * Ensure that once we've read the current tail pointer, that
      * we also see the events that were stored up to the tail.
      */
     smp_rmb();
 
     pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
 
     if (head == tail)
         goto out;
 
     head %= ctx->nr_events;
     tail %= ctx->nr_events;
 
     while (ret < nr) {
         long avail;
         struct io_event *ev;
         struct page *page;
 
         avail = (head <= tail ?  tail : ctx->nr_events) - head;
         if (head == tail)
             break;
 
         pos = head + AIO_EVENTS_OFFSET;
         page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
         pos %= AIO_EVENTS_PER_PAGE;
 
         avail = min(avail, nr - ret);
         avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
 
         ev = kmap(page);
         copy_ret = copy_to_user(event + ret, ev + pos,
                     sizeof(*ev) * avail);
         kunmap(page);
 
         if (unlikely(copy_ret)) {
             ret = -EFAULT;
             goto out;
         }
 
         ret += avail;
         head += avail;
         head %= ctx->nr_events;
     }
 
     ring = kmap_atomic(ctx->ring_pages[0]);
     ring->head = head;
     kunmap_atomic(ring);
     flush_dcache_page(ctx->ring_pages[0]);
 
     pr_debug("%li  h%u t%u\n", ret, head, tail);
 out:
     mutex_unlock(&ctx->ring_lock);
 
     return ret;
 }
 
 static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
                 struct io_event __user *event, long *i)
 {
     long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
 
     if (ret > 0)
         *i += ret;
 
     if (unlikely(atomic_read(&ctx->dead)))
         ret = -EINVAL;
 
     if (!*i)
         *i = ret;
 
     return ret < 0 || *i >= min_nr;
 }
 
 static long read_events(struct kioctx *ctx, long min_nr, long nr,
             struct io_event __user *event,
             ktime_t until)
 {
     long ret = 0;
 
     /*
      * Note that aio_read_events() is being called as the conditional - i.e.
      * we're calling it after prepare_to_wait() has set task state to
      * TASK_INTERRUPTIBLE.
      *
      * But aio_read_events() can block, and if it blocks it's going to flip
      * the task state back to TASK_RUNNING.
      *
      * This should be ok, provided it doesn't flip the state back to
      * TASK_RUNNING and return 0 too much - that causes us to spin. That
      * will only happen if the mutex_lock() call blocks, and we then find
      * the ringbuffer empty. So in practice we should be ok, but it's
      * something to be aware of when touching this code.
      */
     if (until == 0)
         aio_read_events(ctx, min_nr, nr, event, &ret);
     else
         wait_event_interruptible_hrtimeout(ctx->wait,
                 aio_read_events(ctx, min_nr, nr, event, &ret),
                 until);
     return ret;
 }
 
 /* sys_io_setup:
  *  Create an aio_context capable of receiving at least nr_events.
  *  ctxp must not point to an aio_context that already exists, and
  *  must be initialized to 0 prior to the call.  On successful
  *  creation of the aio_context, *ctxp is filled in with the resulting 
  *  handle.  May fail with -EINVAL if *ctxp is not initialized,
  *  if the specified nr_events exceeds internal limits.  May fail 
  *  with -EAGAIN if the specified nr_events exceeds the user's limit 
  *  of available events.  May fail with -ENOMEM if insufficient kernel
  *  resources are available.  May fail with -EFAULT if an invalid
  *  pointer is passed for ctxp.  Will fail with -ENOSYS if not
  *  implemented.
  */
 SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
 {
     struct kioctx *ioctx = NULL;
     unsigned long ctx;
     long ret;
 
     ret = get_user(ctx, ctxp);
     if (unlikely(ret))
         goto out;
 
     ret = -EINVAL;
     if (unlikely(ctx || nr_events == 0)) {
         pr_debug("EINVAL: ctx %lu nr_events %u\n",
                  ctx, nr_events);
         goto out;
     }
 
     ioctx = ioctx_alloc(nr_events);
     ret = PTR_ERR(ioctx);
     if (!IS_ERR(ioctx)) {
         ret = put_user(ioctx->user_id, ctxp);
         if (ret)
             kill_ioctx(current->mm, ioctx, NULL);
         percpu_ref_put(&ioctx->users);
     }
 
 out:
     return ret;
 }
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
 {
     struct kioctx *ioctx = NULL;
     unsigned long ctx;
     long ret;
 
     ret = get_user(ctx, ctx32p);
     if (unlikely(ret))
         goto out;
 
     ret = -EINVAL;
     if (unlikely(ctx || nr_events == 0)) {
         pr_debug("EINVAL: ctx %lu nr_events %u\n",
                  ctx, nr_events);
         goto out;
     }
 
     ioctx = ioctx_alloc(nr_events);
     ret = PTR_ERR(ioctx);
     if (!IS_ERR(ioctx)) {
         /* truncating is ok because it's a user address */
         ret = put_user((u32)ioctx->user_id, ctx32p);
         if (ret)
             kill_ioctx(current->mm, ioctx, NULL);
         percpu_ref_put(&ioctx->users);
     }
 
 out:
     return ret;
 }
 #endif
 
 /* sys_io_destroy:
  *  Destroy the aio_context specified.  May cancel any outstanding 
  *  AIOs and block on completion.  Will fail with -ENOSYS if not
  *  implemented.  May fail with -EINVAL if the context pointed to
  *  is invalid.
  */
 SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
 {
     struct kioctx *ioctx = lookup_ioctx(ctx);
     if (likely(NULL != ioctx)) {
         struct ctx_rq_wait wait;
         int ret;
 
         init_completion(&wait.comp);
         atomic_set(&wait.count, 1);
 
         /* Pass requests_done to kill_ioctx() where it can be set
          * in a thread-safe way. If we try to set it here then we have
          * a race condition if two io_destroy() called simultaneously.
          */
         ret = kill_ioctx(current->mm, ioctx, &wait);
         percpu_ref_put(&ioctx->users);
 
         /* Wait until all IO for the context are done. Otherwise kernel
          * keep using user-space buffers even if user thinks the context
          * is destroyed.
          */
         if (!ret)
             wait_for_completion(&wait.comp);
 
         return ret;
     }
     pr_debug("EINVAL: invalid context id\n");
     return -EINVAL;
 }
 
 static void aio_remove_iocb(struct aio_kiocb *iocb)
 {
     struct kioctx *ctx = iocb->ki_ctx;
     unsigned long flags;
 
     spin_lock_irqsave(&ctx->ctx_lock, flags);
     list_del(&iocb->ki_list);
     spin_unlock_irqrestore(&ctx->ctx_lock, flags);
 }
 
 static void aio_complete_rw(struct kiocb *kiocb, long res)
 {
     struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw);
 
     if (!list_empty_careful(&iocb->ki_list))
         aio_remove_iocb(iocb);
 
     if (kiocb->ki_flags & IOCB_WRITE) {
         struct inode *inode = file_inode(kiocb->ki_filp);
 
         /*
          * Tell lockdep we inherited freeze protection from submission
          * thread.
          */
         if (S_ISREG(inode->i_mode))
             __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
         file_end_write(kiocb->ki_filp);
     }
 
     iocb->ki_res.res = res;
     iocb->ki_res.res2 = 0;
     iocb_put(iocb);
 }
 
 static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 {
     int ret;
 
     req->ki_complete = aio_complete_rw;
     req->private = NULL;
     req->ki_pos = iocb->aio_offset;
     req->ki_flags = req->ki_filp->f_iocb_flags;
     if (iocb->aio_flags & IOCB_FLAG_RESFD)
         req->ki_flags |= IOCB_EVENTFD;
     if (iocb->aio_flags & IOCB_FLAG_IOPRIO) {
         /*
          * If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then
          * aio_reqprio is interpreted as an I/O scheduling
          * class and priority.
          */
         ret = ioprio_check_cap(iocb->aio_reqprio);
         if (ret) {
             pr_debug("aio ioprio check cap error: %d\n", ret);
             return ret;
         }
 
         req->ki_ioprio = iocb->aio_reqprio;
     } else
         req->ki_ioprio = get_current_ioprio();
 
     ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
     if (unlikely(ret))
         return ret;
 
     req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
     return 0;
 }
 
 static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,
         struct iovec **iovec, bool vectored, bool compat,
         struct iov_iter *iter)
 {
     void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
     size_t len = iocb->aio_nbytes;
 
     if (!vectored) {
         ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
         *iovec = NULL;
         return ret;
     }
 
     return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat);
 }
 
 static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
 {
     switch (ret) {
     case -EIOCBQUEUED:
         break;
     case -ERESTARTSYS:
     case -ERESTARTNOINTR:
     case -ERESTARTNOHAND:
     case -ERESTART_RESTARTBLOCK:
         /*
          * There's no easy way to restart the syscall since other AIO's
          * may be already running. Just fail this IO with EINTR.
          */
         ret = -EINTR;
         fallthrough;
     default:
         req->ki_complete(req, ret);
     }
 }
 
 static int aio_read(struct kiocb *req, const struct iocb *iocb,
             bool vectored, bool compat)
 {
     struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
     struct iov_iter iter;
     struct file *file;
     int ret;
 
     ret = aio_prep_rw(req, iocb);
     if (ret)
         return ret;
     file = req->ki_filp;
     if (unlikely(!(file->f_mode & FMODE_READ)))
         return -EBADF;
     if (unlikely(!file->f_op->read_iter))
         return -EINVAL;
 
     ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
     if (ret < 0)
         return ret;
     ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
     if (!ret)
         aio_rw_done(req, call_read_iter(file, req, &iter));
     kfree(iovec);
     return ret;
 }
 
 static int aio_write(struct kiocb *req, const struct iocb *iocb,
              bool vectored, bool compat)
 {
     struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
     struct iov_iter iter;
     struct file *file;
     int ret;
 
     ret = aio_prep_rw(req, iocb);
     if (ret)
         return ret;
     file = req->ki_filp;
 
     if (unlikely(!(file->f_mode & FMODE_WRITE)))
         return -EBADF;
     if (unlikely(!file->f_op->write_iter))
         return -EINVAL;
 
     ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
     if (ret < 0)
         return ret;
     ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
     if (!ret) {
         /*
          * Open-code file_start_write here to grab freeze protection,
          * which will be released by another thread in
          * aio_complete_rw().  Fool lockdep by telling it the lock got
          * released so that it doesn't complain about the held lock when
          * we return to userspace.
          */
         if (S_ISREG(file_inode(file)->i_mode)) {
             sb_start_write(file_inode(file)->i_sb);
             __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
         }
         req->ki_flags |= IOCB_WRITE;
         aio_rw_done(req, call_write_iter(file, req, &iter));
     }
     kfree(iovec);
     return ret;
 }
 
 static void aio_fsync_work(struct work_struct *work)
 {
     struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work);
     const struct cred *old_cred = override_creds(iocb->fsync.creds);
 
     iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync);
     revert_creds(old_cred);
     put_cred(iocb->fsync.creds);
     iocb_put(iocb);
 }
 
 static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
              bool datasync)
 {
     if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes ||
             iocb->aio_rw_flags))
         return -EINVAL;
 
     if (unlikely(!req->file->f_op->fsync))
         return -EINVAL;
 
     req->creds = prepare_creds();
     if (!req->creds)
         return -ENOMEM;
 
     req->datasync = datasync;
     INIT_WORK(&req->work, aio_fsync_work);
     schedule_work(&req->work);
     return 0;
 }
 
 static void aio_poll_put_work(struct work_struct *work)
 {
     struct poll_iocb *req = container_of(work, struct poll_iocb, work);
     struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
 
     iocb_put(iocb);
 }
 
 /*
  * Safely lock the waitqueue which the request is on, synchronizing with the
  * case where the ->poll() provider decides to free its waitqueue early.
  *
  * Returns true on success, meaning that req->head->lock was locked, req->wait
  * is on req->head, and an RCU read lock was taken.  Returns false if the
  * request was already removed from its waitqueue (which might no longer exist).
  */
 static bool poll_iocb_lock_wq(struct poll_iocb *req)
 {
     wait_queue_head_t *head;
 
     /*
      * While we hold the waitqueue lock and the waitqueue is nonempty,
      * wake_up_pollfree() will wait for us.  However, taking the waitqueue
      * lock in the first place can race with the waitqueue being freed.
      *
      * We solve this as eventpoll does: by taking advantage of the fact that
      * all users of wake_up_pollfree() will RCU-delay the actual free.  If
      * we enter rcu_read_lock() and see that the pointer to the queue is
      * non-NULL, we can then lock it without the memory being freed out from
      * under us, then check whether the request is still on the queue.
      *
      * Keep holding rcu_read_lock() as long as we hold the queue lock, in
      * case the caller deletes the entry from the queue, leaving it empty.
      * In that case, only RCU prevents the queue memory from being freed.
      */
     rcu_read_lock();
     head = smp_load_acquire(&req->head);
     if (head) {
         spin_lock(&head->lock);
         if (!list_empty(&req->wait.entry))
             return true;
         spin_unlock(&head->lock);
     }
     rcu_read_unlock();
     return false;
 }
 
 static void poll_iocb_unlock_wq(struct poll_iocb *req)
 {
     spin_unlock(&req->head->lock);
     rcu_read_unlock();
 }
 
 static void aio_poll_complete_work(struct work_struct *work)
 {
     struct poll_iocb *req = container_of(work, struct poll_iocb, work);
     struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
     struct poll_table_struct pt = { ._key = req->events };
     struct kioctx *ctx = iocb->ki_ctx;
     __poll_t mask = 0;
 
     if (!READ_ONCE(req->cancelled))
         mask = vfs_poll(req->file, &pt) & req->events;
 
     /*
      * Note that ->ki_cancel callers also delete iocb from active_reqs after
      * calling ->ki_cancel.  We need the ctx_lock roundtrip here to
      * synchronize with them.  In the cancellation case the list_del_init
      * itself is not actually needed, but harmless so we keep it in to
      * avoid further branches in the fast path.
      */
     spin_lock_irq(&ctx->ctx_lock);
     if (poll_iocb_lock_wq(req)) {
         if (!mask && !READ_ONCE(req->cancelled)) {
             /*
              * The request isn't actually ready to be completed yet.
              * Reschedule completion if another wakeup came in.
              */
             if (req->work_need_resched) {
                 schedule_work(&req->work);
                 req->work_need_resched = false;
             } else {
                 req->work_scheduled = false;
             }
             poll_iocb_unlock_wq(req);
             spin_unlock_irq(&ctx->ctx_lock);
             return;
         }
         list_del_init(&req->wait.entry);
         poll_iocb_unlock_wq(req);
     } /* else, POLLFREE has freed the waitqueue, so we must complete */
     list_del_init(&iocb->ki_list);
     iocb->ki_res.res = mangle_poll(mask);
     spin_unlock_irq(&ctx->ctx_lock);
 
     iocb_put(iocb);
 }
 
 /* assumes we are called with irqs disabled */
 static int aio_poll_cancel(struct kiocb *iocb)
 {
     struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw);
     struct poll_iocb *req = &aiocb->poll;
 
     if (poll_iocb_lock_wq(req)) {
         WRITE_ONCE(req->cancelled, true);
         if (!req->work_scheduled) {
             schedule_work(&aiocb->poll.work);
             req->work_scheduled = true;
         }
         poll_iocb_unlock_wq(req);
     } /* else, the request was force-cancelled by POLLFREE already */
 
     return 0;
 }
 
 static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
         void *key)
 {
     struct poll_iocb *req = container_of(wait, struct poll_iocb, wait);
     struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll);
     __poll_t mask = key_to_poll(key);
     unsigned long flags;
 
     /* for instances that support it check for an event match first: */
     if (mask && !(mask & req->events))
         return 0;
 
     /*
      * Complete the request inline if possible.  This requires that three
      * conditions be met:
      *   1. An event mask must have been passed.  If a plain wakeup was done
      *  instead, then mask == 0 and we have to call vfs_poll() to get
      *  the events, so inline completion isn't possible.
      *   2. The completion work must not have already been scheduled.
      *   3. ctx_lock must not be busy.  We have to use trylock because we
      *  already hold the waitqueue lock, so this inverts the normal
      *  locking order.  Use irqsave/irqrestore because not all
      *  filesystems (e.g. fuse) call this function with IRQs disabled,
      *  yet IRQs have to be disabled before ctx_lock is obtained.
      */
     if (mask && !req->work_scheduled &&
         spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
         struct kioctx *ctx = iocb->ki_ctx;
 
         list_del_init(&req->wait.entry);
         list_del(&iocb->ki_list);
         iocb->ki_res.res = mangle_poll(mask);
         if (iocb->ki_eventfd && !eventfd_signal_allowed()) {
             iocb = NULL;
             INIT_WORK(&req->work, aio_poll_put_work);
             schedule_work(&req->work);
         }
         spin_unlock_irqrestore(&ctx->ctx_lock, flags);
         if (iocb)
             iocb_put(iocb);
     } else {
         /*
          * Schedule the completion work if needed.  If it was already
          * scheduled, record that another wakeup came in.
          *
          * Don't remove the request from the waitqueue here, as it might
          * not actually be complete yet (we won't know until vfs_poll()
          * is called), and we must not miss any wakeups.  POLLFREE is an
          * exception to this; see below.
          */
         if (req->work_scheduled) {
             req->work_need_resched = true;
         } else {
             schedule_work(&req->work);
             req->work_scheduled = true;
         }
 
         /*
          * If the waitqueue is being freed early but we can't complete
          * the request inline, we have to tear down the request as best
          * we can.  That means immediately removing the request from its
          * waitqueue and preventing all further accesses to the
          * waitqueue via the request.  We also need to schedule the
          * completion work (done above).  Also mark the request as
          * cancelled, to potentially skip an unneeded call to ->poll().
          */
         if (mask & POLLFREE) {
             WRITE_ONCE(req->cancelled, true);
             list_del_init(&req->wait.entry);
 
             /*
              * Careful: this *must* be the last step, since as soon
              * as req->head is NULL'ed out, the request can be
              * completed and freed, since aio_poll_complete_work()
              * will no longer need to take the waitqueue lock.
              */
             smp_store_release(&req->head, NULL);
         }
     }
     return 1;
 }
 
 struct aio_poll_table {
     struct poll_table_struct    pt;
     struct aio_kiocb        *iocb;
     bool                queued;
     int             error;
 };
 
 static void
 aio_poll_queue_proc(struct file *file, struct wait_queue_head *head,
         struct poll_table_struct *p)
 {
     struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt);
 
     /* multiple wait queues per file are not supported */
     if (unlikely(pt->queued)) {
         pt->error = -EINVAL;
         return;
     }
 
     pt->queued = true;
     pt->error = 0;
     pt->iocb->poll.head = head;
     add_wait_queue(head, &pt->iocb->poll.wait);
 }
 
 static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
 {
     struct kioctx *ctx = aiocb->ki_ctx;
     struct poll_iocb *req = &aiocb->poll;
     struct aio_poll_table apt;
     bool cancel = false;
     __poll_t mask;
 
     /* reject any unknown events outside the normal event mask. */
     if ((u16)iocb->aio_buf != iocb->aio_buf)
         return -EINVAL;
     /* reject fields that are not defined for poll */
     if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)
         return -EINVAL;
 
     INIT_WORK(&req->work, aio_poll_complete_work);
     req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
 
     req->head = NULL;
     req->cancelled = false;
     req->work_scheduled = false;
     req->work_need_resched = false;
 
     apt.pt._qproc = aio_poll_queue_proc;
     apt.pt._key = req->events;
     apt.iocb = aiocb;
     apt.queued = false;
     apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
 
     /* initialized the list so that we can do list_empty checks */
     INIT_LIST_HEAD(&req->wait.entry);
     init_waitqueue_func_entry(&req->wait, aio_poll_wake);
 
     mask = vfs_poll(req->file, &apt.pt) & req->events;
     spin_lock_irq(&ctx->ctx_lock);
     if (likely(apt.queued)) {
         bool on_queue = poll_iocb_lock_wq(req);
 
         if (!on_queue || req->work_scheduled) {
             /*
              * aio_poll_wake() already either scheduled the async
              * completion work, or completed the request inline.
              */
             if (apt.error) /* unsupported case: multiple queues */
                 cancel = true;
             apt.error = 0;
             mask = 0;
         }
         if (mask || apt.error) {
             /* Steal to complete synchronously. */
             list_del_init(&req->wait.entry);
         } else if (cancel) {
             /* Cancel if possible (may be too late though). */
             WRITE_ONCE(req->cancelled, true);
         } else if (on_queue) {
             /*
              * Actually waiting for an event, so add the request to
              * active_reqs so that it can be cancelled if needed.
              */
             list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
             aiocb->ki_cancel = aio_poll_cancel;
         }
         if (on_queue)
             poll_iocb_unlock_wq(req);
     }
     if (mask) { /* no async, we'd stolen it */
         aiocb->ki_res.res = mangle_poll(mask);
         apt.error = 0;
     }
     spin_unlock_irq(&ctx->ctx_lock);
     if (mask)
         iocb_put(aiocb);
     return apt.error;
 }
 
 static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
                struct iocb __user *user_iocb, struct aio_kiocb *req,
                bool compat)
 {
     req->ki_filp = fget(iocb->aio_fildes);
     if (unlikely(!req->ki_filp))
         return -EBADF;
 
     if (iocb->aio_flags & IOCB_FLAG_RESFD) {
         struct eventfd_ctx *eventfd;
         /*
          * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
          * instance of the file* now. The file descriptor must be
          * an eventfd() fd, and will be signaled for each completed
          * event using the eventfd_signal() function.
          */
         eventfd = eventfd_ctx_fdget(iocb->aio_resfd);
         if (IS_ERR(eventfd))
             return PTR_ERR(eventfd);
 
         req->ki_eventfd = eventfd;
     }
 
     if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) {
         pr_debug("EFAULT: aio_key\n");
         return -EFAULT;
     }
 
     req->ki_res.obj = (u64)(unsigned long)user_iocb;
     req->ki_res.data = iocb->aio_data;
     req->ki_res.res = 0;
     req->ki_res.res2 = 0;
 
     switch (iocb->aio_lio_opcode) {
     case IOCB_CMD_PREAD:
         return aio_read(&req->rw, iocb, false, compat);
     case IOCB_CMD_PWRITE:
         return aio_write(&req->rw, iocb, false, compat);
     case IOCB_CMD_PREADV:
         return aio_read(&req->rw, iocb, true, compat);
     case IOCB_CMD_PWRITEV:
         return aio_write(&req->rw, iocb, true, compat);
     case IOCB_CMD_FSYNC:
         return aio_fsync(&req->fsync, iocb, false);
     case IOCB_CMD_FDSYNC:
         return aio_fsync(&req->fsync, iocb, true);
     case IOCB_CMD_POLL:
         return aio_poll(req, iocb);
     default:
         pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
         return -EINVAL;
     }
 }
 
 static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
              bool compat)
 {
     struct aio_kiocb *req;
     struct iocb iocb;
     int err;
 
     if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb))))
         return -EFAULT;
 
     /* enforce forwards compatibility on users */
     if (unlikely(iocb.aio_reserved2)) {
         pr_debug("EINVAL: reserve field set\n");
         return -EINVAL;
     }
 
     /* prevent overflows */
     if (unlikely(
         (iocb.aio_buf != (unsigned long)iocb.aio_buf) ||
         (iocb.aio_nbytes != (size_t)iocb.aio_nbytes) ||
         ((ssize_t)iocb.aio_nbytes < 0)
        )) {
         pr_debug("EINVAL: overflow check\n");
         return -EINVAL;
     }
 
     req = aio_get_req(ctx);
     if (unlikely(!req))
         return -EAGAIN;
 
     err = __io_submit_one(ctx, &iocb, user_iocb, req, compat);
 
     /* Done with the synchronous reference */
     iocb_put(req);
 
     /*
      * If err is 0, we'd either done aio_complete() ourselves or have
      * arranged for that to be done asynchronously.  Anything non-zero
      * means that we need to destroy req ourselves.
      */
     if (unlikely(err)) {
         iocb_destroy(req);
         put_reqs_available(ctx, 1);
     }
     return err;
 }
 
 /* sys_io_submit:
  *  Queue the nr iocbs pointed to by iocbpp for processing.  Returns
  *  the number of iocbs queued.  May return -EINVAL if the aio_context
  *  specified by ctx_id is invalid, if nr is < 0, if the iocb at
  *  *iocbpp[0] is not properly initialized, if the operation specified
  *  is invalid for the file descriptor in the iocb.  May fail with
  *  -EFAULT if any of the data structures point to invalid data.  May
  *  fail with -EBADF if the file descriptor specified in the first
  *  iocb is invalid.  May fail with -EAGAIN if insufficient resources
  *  are available to queue any iocbs.  Will return 0 if nr is 0.  Will
  *  fail with -ENOSYS if not implemented.
  */
 SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
         struct iocb __user * __user *, iocbpp)
 {
     struct kioctx *ctx;
     long ret = 0;
     int i = 0;
     struct blk_plug plug;
 
     if (unlikely(nr < 0))
         return -EINVAL;
 
     ctx = lookup_ioctx(ctx_id);
     if (unlikely(!ctx)) {
         pr_debug("EINVAL: invalid context id\n");
         return -EINVAL;
     }
 
     if (nr > ctx->nr_events)
         nr = ctx->nr_events;
 
     if (nr > AIO_PLUG_THRESHOLD)
         blk_start_plug(&plug);
     for (i = 0; i < nr; i++) {
         struct iocb __user *user_iocb;
 
         if (unlikely(get_user(user_iocb, iocbpp + i))) {
             ret = -EFAULT;
             break;
         }
 
         ret = io_submit_one(ctx, user_iocb, false);
         if (ret)
             break;
     }
     if (nr > AIO_PLUG_THRESHOLD)
         blk_finish_plug(&plug);
 
     percpu_ref_put(&ctx->users);
     return i ? i : ret;
 }
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
                int, nr, compat_uptr_t __user *, iocbpp)
 {
     struct kioctx *ctx;
     long ret = 0;
     int i = 0;
     struct blk_plug plug;
 
     if (unlikely(nr < 0))
         return -EINVAL;
 
     ctx = lookup_ioctx(ctx_id);
     if (unlikely(!ctx)) {
         pr_debug("EINVAL: invalid context id\n");
         return -EINVAL;
     }
 
     if (nr > ctx->nr_events)
         nr = ctx->nr_events;
 
     if (nr > AIO_PLUG_THRESHOLD)
         blk_start_plug(&plug);
     for (i = 0; i < nr; i++) {
         compat_uptr_t user_iocb;
 
         if (unlikely(get_user(user_iocb, iocbpp + i))) {
             ret = -EFAULT;
             break;
         }
 
         ret = io_submit_one(ctx, compat_ptr(user_iocb), true);
         if (ret)
             break;
     }
     if (nr > AIO_PLUG_THRESHOLD)
         blk_finish_plug(&plug);
 
     percpu_ref_put(&ctx->users);
     return i ? i : ret;
 }
 #endif
 
 /* sys_io_cancel:
  *  Attempts to cancel an iocb previously passed to io_submit.  If
  *  the operation is successfully cancelled, the resulting event is
  *  copied into the memory pointed to by result without being placed
  *  into the completion queue and 0 is returned.  May fail with
  *  -EFAULT if any of the data structures pointed to are invalid.
  *  May fail with -EINVAL if aio_context specified by ctx_id is
  *  invalid.  May fail with -EAGAIN if the iocb specified was not
  *  cancelled.  Will fail with -ENOSYS if not implemented.
  */
 SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
         struct io_event __user *, result)
 {
     struct kioctx *ctx;
     struct aio_kiocb *kiocb;
     int ret = -EINVAL;
     u32 key;
     u64 obj = (u64)(unsigned long)iocb;
 
     if (unlikely(get_user(key, &iocb->aio_key)))
         return -EFAULT;
     if (unlikely(key != KIOCB_KEY))
         return -EINVAL;
 
     ctx = lookup_ioctx(ctx_id);
     if (unlikely(!ctx))
         return -EINVAL;
 
     spin_lock_irq(&ctx->ctx_lock);
     /* TODO: use a hash or array, this sucks. */
     list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
         if (kiocb->ki_res.obj == obj) {
             ret = kiocb->ki_cancel(&kiocb->rw);
             list_del_init(&kiocb->ki_list);
             break;
         }
     }
     spin_unlock_irq(&ctx->ctx_lock);
 
     if (!ret) {
         /*
          * The result argument is no longer used - the io_event is
          * always delivered via the ring buffer. -EINPROGRESS indicates
          * cancellation is progress:
          */
         ret = -EINPROGRESS;
     }
 
     percpu_ref_put(&ctx->users);
 
     return ret;
 }
 
 static long do_io_getevents(aio_context_t ctx_id,
         long min_nr,
         long nr,
         struct io_event __user *events,
         struct timespec64 *ts)
 {
     ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX;
     struct kioctx *ioctx = lookup_ioctx(ctx_id);
     long ret = -EINVAL;
 
     if (likely(ioctx)) {
         if (likely(min_nr <= nr && min_nr >= 0))
             ret = read_events(ioctx, min_nr, nr, events, until);
         percpu_ref_put(&ioctx->users);
     }
 
     return ret;
 }
 
 /* io_getevents:
  *  Attempts to read at least min_nr events and up to nr events from
  *  the completion queue for the aio_context specified by ctx_id. If
  *  it succeeds, the number of read events is returned. May fail with
  *  -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
  *  out of range, if timeout is out of range.  May fail with -EFAULT
  *  if any of the memory specified is invalid.  May return 0 or
  *  < min_nr if the timeout specified by timeout has elapsed
  *  before sufficient events are available, where timeout == NULL
  *  specifies an infinite timeout. Note that the timeout pointed to by
  *  timeout is relative.  Will fail with -ENOSYS if not implemented.
  */
 #ifdef CONFIG_64BIT
 
 SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
         long, min_nr,
         long, nr,
         struct io_event __user *, events,
         struct __kernel_timespec __user *, timeout)
 {
     struct timespec64   ts;
     int         ret;
 
     if (timeout && unlikely(get_timespec64(&ts, timeout)))
         return -EFAULT;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
     if (!ret && signal_pending(current))
         ret = -EINTR;
     return ret;
 }
 
 #endif
 
 struct __aio_sigset {
     const sigset_t __user   *sigmask;
     size_t      sigsetsize;
 };
 
 SYSCALL_DEFINE6(io_pgetevents,
         aio_context_t, ctx_id,
         long, min_nr,
         long, nr,
         struct io_event __user *, events,
         struct __kernel_timespec __user *, timeout,
         const struct __aio_sigset __user *, usig)
 {
     struct __aio_sigset ksig = { NULL, };
     struct timespec64   ts;
     bool interrupted;
     int ret;
 
     if (timeout && unlikely(get_timespec64(&ts, timeout)))
         return -EFAULT;
 
     if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
         return -EFAULT;
 
     ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
     if (ret)
         return ret;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
 
     interrupted = signal_pending(current);
     restore_saved_sigmask_unless(interrupted);
     if (interrupted && !ret)
         ret = -ERESTARTNOHAND;
 
     return ret;
 }
 
 #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
 
 SYSCALL_DEFINE6(io_pgetevents_time32,
         aio_context_t, ctx_id,
         long, min_nr,
         long, nr,
         struct io_event __user *, events,
         struct old_timespec32 __user *, timeout,
         const struct __aio_sigset __user *, usig)
 {
     struct __aio_sigset ksig = { NULL, };
     struct timespec64   ts;
     bool interrupted;
     int ret;
 
     if (timeout && unlikely(get_old_timespec32(&ts, timeout)))
         return -EFAULT;
 
     if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
         return -EFAULT;
 
 
     ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize);
     if (ret)
         return ret;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL);
 
     interrupted = signal_pending(current);
     restore_saved_sigmask_unless(interrupted);
     if (interrupted && !ret)
         ret = -ERESTARTNOHAND;
 
     return ret;
 }
 
 #endif
 
 #if defined(CONFIG_COMPAT_32BIT_TIME)
 
 SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id,
         __s32, min_nr,
         __s32, nr,
         struct io_event __user *, events,
         struct old_timespec32 __user *, timeout)
 {
     struct timespec64 t;
     int ret;
 
     if (timeout && get_old_timespec32(&t, timeout))
         return -EFAULT;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
     if (!ret && signal_pending(current))
         ret = -EINTR;
     return ret;
 }
 
 #endif
 
 #ifdef CONFIG_COMPAT
 
 struct __compat_aio_sigset {
     compat_uptr_t       sigmask;
     compat_size_t       sigsetsize;
 };
 
 #if defined(CONFIG_COMPAT_32BIT_TIME)
 
 COMPAT_SYSCALL_DEFINE6(io_pgetevents,
         compat_aio_context_t, ctx_id,
         compat_long_t, min_nr,
         compat_long_t, nr,
         struct io_event __user *, events,
         struct old_timespec32 __user *, timeout,
         const struct __compat_aio_sigset __user *, usig)
 {
     struct __compat_aio_sigset ksig = { 0, };
     struct timespec64 t;
     bool interrupted;
     int ret;
 
     if (timeout && get_old_timespec32(&t, timeout))
         return -EFAULT;
 
     if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
         return -EFAULT;
 
     ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
     if (ret)
         return ret;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
 
     interrupted = signal_pending(current);
     restore_saved_sigmask_unless(interrupted);
     if (interrupted && !ret)
         ret = -ERESTARTNOHAND;
 
     return ret;
 }
 
 #endif
 
 COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64,
         compat_aio_context_t, ctx_id,
         compat_long_t, min_nr,
         compat_long_t, nr,
         struct io_event __user *, events,
         struct __kernel_timespec __user *, timeout,
         const struct __compat_aio_sigset __user *, usig)
 {
     struct __compat_aio_sigset ksig = { 0, };
     struct timespec64 t;
     bool interrupted;
     int ret;
 
     if (timeout && get_timespec64(&t, timeout))
         return -EFAULT;
 
     if (usig && copy_from_user(&ksig, usig, sizeof(ksig)))
         return -EFAULT;
 
     ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize);
     if (ret)
         return ret;
 
     ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL);
 
     interrupted = signal_pending(current);
     restore_saved_sigmask_unless(interrupted);
     if (interrupted && !ret)
         ret = -ERESTARTNOHAND;
 
     return ret;
 }
 #endif

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