[PATCH] fs/aio.c: Cosmetic

From: Alejandro Colomar
Date: Mon Nov 02 2020 - 10:26:27 EST

Changes:
- Consistently use 'unsigned int', instead of 'unsigned'.
- Add a blank line after variable declarations.
- Move variable declarations to the top of functions.
- Add a blank line at the top of functions if there are no declarations.
- Invert logic of 'if's to reduce indentation and simplify function logic.
- Add goto tags when needed.
- Early return when appropriate.
- Add braces to 'else' if the corresponding 'if' used braces.
- Replace spaces by tabs

This patch does not introduce any actual changes in behavior.

Signed-off-by: Alejandro Colomar <colomar.6.4.3@xxxxxxxxx>
---

[[ CC: fix typo in kvack.org ]]

Hello Benjamin,

I found some inconsistencies in the code here
when fixing the manual page for io_setup(3).

I compiled the whole fs (`make fs`):
I used the .config file from debian testing.
No warnings; it compiles fine after the changes.

However I didn't compile the whole kernel (my system got out of space :( ).

This patch should not change any behavior.

Cheers,

Alex

P.S.: I resent the email as I had a typo in the list email.


fs/aio.c | 390 +++++++++++++++++++++++++++++--------------------------
1 file changed, 208 insertions(+), 182 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index d5ec30385566..9d7dc92a6d7d 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -55,16 +55,16 @@
#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
+ unsigned int id; /* kernel internal index number */
+ unsigned int nr; /* number of io_events */
+ unsigned int head; /* Written to by userland or under ring_lock
* mutex by aio_read_events_ring(). */
- unsigned tail;
+ unsigned int tail;

- unsigned magic;
- unsigned compat_features;
- unsigned incompat_features;
- unsigned header_length; /* size of aio_ring */
+ unsigned int magic;
+ unsigned int compat_features;
+ unsigned int incompat_features;
+ unsigned int header_length; /* size of aio_ring */


struct io_event io_events[];
@@ -80,12 +80,12 @@ struct aio_ring {

struct kioctx_table {
struct rcu_head rcu;
- unsigned nr;
+ unsigned int nr;
struct kioctx __rcu *table[];
};

struct kioctx_cpu {
- unsigned reqs_available;
+ unsigned int reqs_available;
};

struct ctx_rq_wait {
@@ -107,7 +107,7 @@ struct kioctx {
* For percpu reqs_available, number of slots we move to/from global
* counter at a time:
*/
- unsigned req_batch;
+ unsigned int req_batch;
/*
* This is what userspace passed to io_setup(), it's not used for
* anything but counting against the global max_reqs quota.
@@ -115,10 +115,10 @@ struct kioctx {
* The real limit is nr_events - 1, which will be larger (see
* aio_setup_ring())
*/
- unsigned max_reqs;
+ unsigned int max_reqs;

/* Size of ringbuffer, in units of struct io_event */
- unsigned nr_events;
+ unsigned int nr_events;

unsigned long mmap_base;
unsigned long mmap_size;
@@ -156,15 +156,15 @@ struct kioctx {
} ____cacheline_aligned_in_smp;

struct {
- unsigned tail;
- unsigned completed_events;
+ unsigned int tail;
+ unsigned int completed_events;
spinlock_t completion_lock;
} ____cacheline_aligned_in_smp;

struct page *internal_pages[AIO_RING_PAGES];
struct file *aio_ring_file;

- unsigned id;
+ unsigned int id;
};

/*
@@ -236,6 +236,7 @@ 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);

@@ -252,6 +253,7 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)

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;
@@ -269,6 +271,7 @@ static int __init aio_setup(void)
.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.");
@@ -284,18 +287,19 @@ 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);
+ if (!aio_ring_file)
+ return;

- /* 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);
+ truncate_setsize(file_inode(aio_ring_file), 0);

- fput(aio_ring_file);
- }
+ /* 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)
@@ -363,6 +367,7 @@ static const struct vm_operations_struct aio_ring_vm_ops = {

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;
@@ -413,8 +418,9 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
/* Make sure the old page hasn't already been changed */
if (ctx->ring_pages[idx] != old)
rc = -EAGAIN;
- } else
+ } else {
rc = -EINVAL;
+ }

if (rc != 0)
goto out_unlock;
@@ -632,7 +638,7 @@ static void free_ioctx_users(struct percpu_ref *ref)

static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
{
- unsigned i, new_nr;
+ unsigned int i, new_nr;
struct kioctx_table *table, *old;
struct aio_ring *ring;

@@ -640,23 +646,27 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
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;
- }
-
+ if (!table)
+ goto new_table;
+
+ for (i = 0; i < table->nr; i++) {
+ if (rcu_access_pointer(table->table[i]))
+ continue;
+
+ 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_table:
new_nr = (table ? table->nr : 1) * 4;
spin_unlock(&mm->ioctx_lock);

@@ -685,8 +695,9 @@ static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
}
}

-static void aio_nr_sub(unsigned nr)
+static void aio_nr_sub(unsigned int nr)
{
+
spin_lock(&aio_nr_lock);
if (WARN_ON(aio_nr - nr > aio_nr))
aio_nr = 0;
@@ -698,7 +709,7 @@ static void aio_nr_sub(unsigned nr)
/* ioctx_alloc
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
*/
-static struct kioctx *ioctx_alloc(unsigned nr_events)
+static struct kioctx *ioctx_alloc(unsigned int nr_events)
{
struct mm_struct *mm = current->mm;
struct kioctx *ctx;
@@ -899,7 +910,7 @@ void exit_aio(struct mm_struct *mm)
kfree(table);
}

-static void put_reqs_available(struct kioctx *ctx, unsigned nr)
+static void put_reqs_available(struct kioctx *ctx, unsigned int nr)
{
struct kioctx_cpu *kcpu;
unsigned long flags;
@@ -924,21 +935,23 @@ static bool __get_reqs_available(struct kioctx *ctx)

local_irq_save(flags);
kcpu = this_cpu_ptr(ctx->cpu);
- if (!kcpu->reqs_available) {
- int old, avail = atomic_read(&ctx->reqs_available);
+ if (kcpu->reqs_available)
+ goto kcpu_reqs_avail;
+
+ int old, avail = atomic_read(&ctx->reqs_available);

- do {
- if (avail < ctx->req_batch)
- goto out;
+ do {
+ if (avail < ctx->req_batch)
+ goto out;

- old = avail;
- avail = atomic_cmpxchg(&ctx->reqs_available,
- avail, avail - ctx->req_batch);
- } while (avail != old);
+ old = avail;
+ avail = atomic_cmpxchg(&ctx->reqs_available,
+ avail, avail - ctx->req_batch);
+ } while (avail != old);

- kcpu->reqs_available += ctx->req_batch;
- }
+ kcpu->reqs_available += ctx->req_batch;

+kcpu_reqs_avail:
ret = true;
kcpu->reqs_available--;
out:
@@ -953,10 +966,10 @@ static bool __get_reqs_available(struct kioctx *ctx)
* 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)
+static void refill_reqs_available(struct kioctx *ctx, unsigned int head,
+ unsigned int tail)
{
- unsigned events_in_ring, completed;
+ unsigned int events_in_ring, completed;

/* Clamp head since userland can write to it. */
head %= ctx->nr_events;
@@ -984,32 +997,34 @@ static void refill_reqs_available(struct kioctx *ctx, unsigned head,
*/
static void user_refill_reqs_available(struct kioctx *ctx)
{
+ struct aio_ring *ring;
+ unsigned int head;
+
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);
+ if (!ctx->completed_events)
+ goto out;

- refill_reqs_available(ctx, head, ctx->tail);
- }
+ /* 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);
+out:
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);
@@ -1050,7 +1065,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
struct mm_struct *mm = current->mm;
struct kioctx *ctx, *ret = NULL;
struct kioctx_table *table;
- unsigned id;
+ unsigned int id;

if (get_user(id, &ring->id))
return NULL;
@@ -1074,6 +1089,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)

static inline void iocb_destroy(struct aio_kiocb *iocb)
{
+
if (iocb->ki_eventfd)
eventfd_ctx_put(iocb->ki_eventfd);
if (iocb->ki_filp)
@@ -1090,7 +1106,7 @@ 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 int tail, pos, head;
unsigned long flags;

/*
@@ -1160,10 +1176,11 @@ static void aio_complete(struct aio_kiocb *iocb)

static inline void iocb_put(struct aio_kiocb *iocb)
{
- if (refcount_dec_and_test(&iocb->ki_refcnt)) {
- aio_complete(iocb);
- iocb_destroy(iocb);
- }
+
+ if (!refcount_dec_and_test(&iocb->ki_refcnt))
+ return;
+ aio_complete(iocb);
+ iocb_destroy(iocb);
}

/* aio_read_events_ring
@@ -1174,7 +1191,7 @@ static long aio_read_events_ring(struct kioctx *ctx,
struct io_event __user *event, long nr)
{
struct aio_ring *ring;
- unsigned head, tail, pos;
+ unsigned int head, tail, pos;
long ret = 0;
int copy_ret;

@@ -1309,7 +1326,7 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr,
* pointer is passed for ctxp. Will fail with -ENOSYS if not
* implemented.
*/
-SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
+SYSCALL_DEFINE2(io_setup, unsigned int, nr_events, aio_context_t __user *, ctxp)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
@@ -1328,19 +1345,19 @@ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)

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);
- }
+ if (IS_ERR(ioctx))
+ goto out;
+ 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)
+COMPAT_SYSCALL_DEFINE2(io_setup, unsigned int, nr_events, u32 __user *, ctx32p)
{
struct kioctx *ioctx = NULL;
unsigned long ctx;
@@ -1359,13 +1376,13 @@ COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)

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);
- }
+ if (IS_ERR(ioctx))
+ goto out;
+ /* 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;
@@ -1381,31 +1398,32 @@ COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
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;
+ struct ctx_rq_wait wait;
+ int ret;

- init_completion(&wait.comp);
- atomic_set(&wait.count, 1);
+ if (unlikely(!ioctx)) {
+ pr_debug("EINVAL: invalid context id\n");
+ return -EINVAL;
+ }

- /* 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);
+ init_completion(&wait.comp);
+ atomic_set(&wait.count, 1);

- /* 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);
+ /* 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);

- return ret;
- }
- pr_debug("EINVAL: invalid context id\n");
- return -EINVAL;
+ /* 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;
}

static void aio_remove_iocb(struct aio_kiocb *iocb)
@@ -1466,8 +1484,9 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
}

req->ki_ioprio = iocb->aio_reqprio;
- } else
+ } else {
req->ki_ioprio = get_current_ioprio();
+ }

ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
if (unlikely(ret))
@@ -1499,6 +1518,7 @@ static ssize_t aio_setup_rw(int rw, const struct iocb *iocb,

static inline void aio_rw_done(struct kiocb *req, ssize_t ret)
{
+
switch (ret) {
case -EIOCBQUEUED:
break;
@@ -1567,21 +1587,23 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb,
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_FREEZE_WRITE, true);
- __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));
+ if (ret)
+ goto out;
+
+ /*
+ * 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_FREEZE_WRITE, true);
+ __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));
+out:
kfree(iovec);
return ret;
}
@@ -1674,8 +1696,8 @@ static int aio_poll_cancel(struct kiocb *iocb)
return 0;
}

-static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
- void *key)
+static int aio_poll_wake(struct wait_queue_entry *wait, unsigned int 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);
@@ -1688,29 +1710,31 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,

list_del_init(&req->wait.entry);

- if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
- struct kioctx *ctx = iocb->ki_ctx;
+ if (!(mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags))) {
+ schedule_work(&req->work);
+ return 1;
+ }

- /*
- * Try to complete the iocb inline if we can. Use
- * irqsave/irqrestore because not all filesystems (e.g. fuse)
- * call this function with IRQs disabled and because IRQs
- * have to be disabled before ctx_lock is obtained.
- */
- list_del(&iocb->ki_list);
- iocb->ki_res.res = mangle_poll(mask);
- req->done = true;
- if (iocb->ki_eventfd && eventfd_signal_count()) {
- 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 {
+ struct kioctx *ctx = iocb->ki_ctx;
+
+ /*
+ * Try to complete the iocb inline if we can. Use
+ * irqsave/irqrestore because not all filesystems (e.g. fuse)
+ * call this function with IRQs disabled and because IRQs
+ * have to be disabled before ctx_lock is obtained.
+ */
+ list_del(&iocb->ki_list);
+ iocb->ki_res.res = mangle_poll(mask);
+ req->done = true;
+ if (iocb->ki_eventfd && eventfd_signal_count()) {
+ 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);
+
return 1;
}

@@ -1770,24 +1794,25 @@ static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)

mask = vfs_poll(req->file, &apt.pt) & req->events;
spin_lock_irq(&ctx->ctx_lock);
- if (likely(req->head)) {
- spin_lock(&req->head->lock);
- if (unlikely(list_empty(&req->wait.entry))) {
- if (apt.error)
- cancel = true;
- apt.error = 0;
- mask = 0;
- }
- if (mask || apt.error) {
- list_del_init(&req->wait.entry);
- } else if (cancel) {
- WRITE_ONCE(req->cancelled, true);
- } else if (!req->done) { /* actually waiting for an event */
- list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
- aiocb->ki_cancel = aio_poll_cancel;
- }
- spin_unlock(&req->head->lock);
+ if (unlikely(!req->head))
+ goto out;
+ spin_lock(&req->head->lock);
+ if (unlikely(list_empty(&req->wait.entry))) {
+ if (apt.error)
+ cancel = true;
+ apt.error = 0;
+ mask = 0;
+ }
+ if (mask || apt.error) {
+ list_del_init(&req->wait.entry);
+ } else if (cancel) {
+ WRITE_ONCE(req->cancelled, true);
+ } else if (!req->done) { /* actually waiting for an event */
+ list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
+ aiocb->ki_cancel = aio_poll_cancel;
}
+ spin_unlock(&req->head->lock);
+out:
if (mask) { /* no async, we'd stolen it */
aiocb->ki_res.res = mangle_poll(mask);
apt.error = 0;
@@ -2058,11 +2083,12 @@ static long do_io_getevents(aio_context_t ctx_id,
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);
- }
+ if (unlikely(!ioctx))
+ return -EINVAL;
+
+ if (likely(min_nr <= nr && min_nr >= 0))
+ ret = read_events(ioctx, min_nr, nr, events, until);
+ percpu_ref_put(&ioctx->users);

return ret;
}
--
2.28.0