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Message-ID: <tencent_1D2E4866B2223D9A19DF4FFB79AFAA955A05@qq.com>
Date: Sat, 24 Dec 2022 22:36:20 +0800
From: wenyang.linux@...mail.com
To: Alexander Viro <viro@...iv.linux.org.uk>
Cc: Wen Yang <wenyang.linux@...mail.com>,
kernel test robot <lkp@...el.com>,
Dan Carpenter <error27@...il.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] eventfd: use a generic helper instead of an open coded wait_event
From: Wen Yang <wenyang.linux@...mail.com>
Use wait_event_interruptible_locked_irq() in the eventfd_{write,read} to
avoid the longer, open coded equivalent.
Signed-off-by: Wen Yang <wenyang.linux@...mail.com>
Cc: Alexander Viro <viro@...iv.linux.org.uk>
Cc: kernel test robot <lkp@...el.com>
Cc: Dan Carpenter <error27@...il.com>
Cc: linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
v2:
- fix smatch warnings: eventfd_read() warn: inconsistent returns '&ctx->wqh.lock'.
fs/eventfd.c | 41 +++++++----------------------------------
1 file changed, 7 insertions(+), 34 deletions(-)
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 249ca6c0b784..c5bda3df4a28 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -228,7 +228,6 @@ static ssize_t eventfd_read(struct kiocb *iocb, struct iov_iter *to)
struct file *file = iocb->ki_filp;
struct eventfd_ctx *ctx = file->private_data;
__u64 ucnt = 0;
- DECLARE_WAITQUEUE(wait, current);
if (iov_iter_count(to) < sizeof(ucnt))
return -EINVAL;
@@ -239,23 +238,11 @@ static ssize_t eventfd_read(struct kiocb *iocb, struct iov_iter *to)
spin_unlock_irq(&ctx->wqh.lock);
return -EAGAIN;
}
- __add_wait_queue(&ctx->wqh, &wait);
- for (;;) {
- set_current_state(TASK_INTERRUPTIBLE);
- if (ctx->count)
- break;
- if (signal_pending(current)) {
- __remove_wait_queue(&ctx->wqh, &wait);
- __set_current_state(TASK_RUNNING);
- spin_unlock_irq(&ctx->wqh.lock);
- return -ERESTARTSYS;
- }
+
+ if (wait_event_interruptible_locked_irq(ctx->wqh, ctx->count)) {
spin_unlock_irq(&ctx->wqh.lock);
- schedule();
- spin_lock_irq(&ctx->wqh.lock);
+ return -ERESTARTSYS;
}
- __remove_wait_queue(&ctx->wqh, &wait);
- __set_current_state(TASK_RUNNING);
}
eventfd_ctx_do_read(ctx, &ucnt);
current->in_eventfd = 1;
@@ -275,7 +262,6 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
struct eventfd_ctx *ctx = file->private_data;
ssize_t res;
__u64 ucnt;
- DECLARE_WAITQUEUE(wait, current);
if (count < sizeof(ucnt))
return -EINVAL;
@@ -288,23 +274,10 @@ static ssize_t eventfd_write(struct file *file, const char __user *buf, size_t c
if (ULLONG_MAX - ctx->count > ucnt)
res = sizeof(ucnt);
else if (!(file->f_flags & O_NONBLOCK)) {
- __add_wait_queue(&ctx->wqh, &wait);
- for (res = 0;;) {
- set_current_state(TASK_INTERRUPTIBLE);
- if (ULLONG_MAX - ctx->count > ucnt) {
- res = sizeof(ucnt);
- break;
- }
- if (signal_pending(current)) {
- res = -ERESTARTSYS;
- break;
- }
- spin_unlock_irq(&ctx->wqh.lock);
- schedule();
- spin_lock_irq(&ctx->wqh.lock);
- }
- __remove_wait_queue(&ctx->wqh, &wait);
- __set_current_state(TASK_RUNNING);
+ res = wait_event_interruptible_locked_irq(ctx->wqh,
+ ULLONG_MAX - ctx->count > ucnt);
+ if (!res)
+ res = sizeof(ucnt);
}
if (likely(res > 0)) {
ctx->count += ucnt;
--
2.25.1
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