From 914c68686441c93f6954267dabef6c936ebb479f Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Thu, 7 Feb 2019 06:49:43 -0500
Subject: [PATCH] media: vb2: fix epoll() by calling poll_wait first
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 vb2_core_poll() and vb2_poll(). Fix this,
otherwise epoll() would timeout when it shouldn't.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Yi Qingliang <niqingliang2003@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
drivers/media/common/videobuf2/videobuf2-core.c | 4 ++--
drivers/media/common/videobuf2/videobuf2-v4l2.c | 4 +---
2 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 275cddd8808c..15b6b9c0a2e4 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -2291,6 +2291,8 @@ __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
if (q->is_output && !(req_events & (EPOLLOUT | EPOLLWRNORM)))
return 0;
+ poll_wait(file, &q->done_wq, wait);
+
/*
* Start file I/O emulator only if streaming API has not been used yet.
*/
@@ -2342,8 +2344,6 @@ __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
*/
if (q->last_buffer_dequeued)
return EPOLLIN | EPOLLRDNORM;
-
- poll_wait(file, &q->done_wq, wait);
}
/*
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 55277370c313..d09dee20e421 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -868,16 +868,14 @@ EXPORT_SYMBOL_GPL(vb2_queue_release);
__poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
{
struct video_device *vfd = video_devdata(file);
- __poll_t req_events = poll_requested_events(wait);
__poll_t res = 0;
if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
struct v4l2_fh *fh = file->private_data;
+ poll_wait(file, &fh->wait, wait);
if (v4l2_event_pending(fh))
res = EPOLLPRI;
- else if (req_events & EPOLLPRI)
- poll_wait(file, &fh->wait, wait);
}
return res | vb2_core_poll(q, file, wait);