LinuxTV Patchwork [RFC,2/8] media-request: fix epoll() by calling poll_wait first

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Submitter Hans Verkuil
Date Feb. 7, 2019, 11:49 a.m.
Message ID <20190207114948.37750-3-hverkuil-cisco@xs4all.nl>
Download mbox | patch
Permalink /patch/54366/
State Accepted
Delegated to: Hans Verkuil
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Comments

Hans Verkuil - Feb. 7, 2019, 11:49 a.m.
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

The epoll function expects that whenever the poll file op is
called, the poll_wait function is also called. That didn't
always happen in media_request_poll(). Fix this, otherwise
epoll() would timeout when it shouldn't.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/media-request.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Patch

diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
index c71a34ae6383..eec2e2b2f6ec 100644
--- a/drivers/media/media-request.c
+++ b/drivers/media/media-request.c
@@ -100,6 +100,7 @@  static __poll_t media_request_poll(struct file *filp,
 	if (!(poll_requested_events(wait) & EPOLLPRI))
 		return 0;
 
+	poll_wait(filp, &req->poll_wait, wait);
 	spin_lock_irqsave(&req->lock, flags);
 	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
 		ret = EPOLLPRI;
@@ -110,8 +111,6 @@  static __poll_t media_request_poll(struct file *filp,
 		goto unlock;
 	}
 
-	poll_wait(filp, &req->poll_wait, wait);
-
 unlock:
 	spin_unlock_irqrestore(&req->lock, flags);
 	return ret;

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