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media: v4l2-mem2mem: reorder checks in v4l2_m2m_poll()

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When reaching the end of stream, V4L2 m2m clients may expect the
V4L2_EOS_EVENT. Although the V4L2_EOS_EVENT is deprecated behavior,
drivers must signal that event before dequeuing the buffer that has the
V4L2_BUF_FLAG_LAST flag set.

If a driver queues the V4L2_EOS_EVENT event and returns the buffer after
the check for events but before the check for buffers, vb2_m2m_poll()
will signal that the buffer with V4L2_BUF_FLAG_LAST can be read but not
that the V4L2_EOS_EVENT is available.

Split the check for buffers into a separate function and check for
available buffers before checking for events. This ensures that if
vb2_m2m_poll() signals POLLIN | POLLRDNORM for the V4L2_BUF_FLAG_LAST
buffer, it signals POLLPRI for the V4L2_EOS_EVENT, too.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: fix checkpatch alignment warning]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Michael Tretter 2019-06-27 08:44:33 -04:00 committed by Mauro Carvalho Chehab
parent 8d86a15649
commit 7708065f5d
1 changed files with 27 additions and 20 deletions
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47
drivers/media/v4l2-core/v4l2-mem2mem.c
View file

@ -603,11 +603,10 @@ int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
}
EXPORT_SYMBOL_GPL(v4l2_m2m_streamoff);
__poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait)
static __poll_t v4l2_m2m_poll_for_data(struct file *file,
struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait)
{
struct video_device *vfd = video_devdata(file);
__poll_t req_events = poll_requested_events(wait);
struct vb2_queue *src_q, *dst_q;
struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;
__poll_t rc = 0;
@ -619,16 +618,6 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
poll_wait(file, &src_q->done_wq, wait);
poll_wait(file, &dst_q->done_wq, wait);
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))
rc = EPOLLPRI;
if (!(req_events & (EPOLLOUT | EPOLLWRNORM | EPOLLIN | EPOLLRDNORM)))
return rc;
}
/*
* There has to be at least one buffer queued on each queued_list, which
* means either in driver already or waiting for driver to claim it
@ -637,10 +626,8 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
if ((!src_q->streaming || src_q->error ||
list_empty(&src_q->queued_list)) &&
(!dst_q->streaming || dst_q->error ||
list_empty(&dst_q->queued_list))) {
rc |= EPOLLERR;
goto end;
}
list_empty(&dst_q->queued_list)))
return EPOLLERR;
spin_lock_irqsave(&dst_q->done_lock, flags);
if (list_empty(&dst_q->done_list)) {
@ -650,7 +637,7 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
*/
if (dst_q->last_buffer_dequeued) {
spin_unlock_irqrestore(&dst_q->done_lock, flags);
return rc | EPOLLIN | EPOLLRDNORM;
return EPOLLIN | EPOLLRDNORM;
}
}
spin_unlock_irqrestore(&dst_q->done_lock, flags);
@ -673,7 +660,27 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
rc |= EPOLLIN | EPOLLRDNORM;
spin_unlock_irqrestore(&dst_q->done_lock, flags);
end:
return rc;
}
__poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait)
{
struct video_device *vfd = video_devdata(file);
__poll_t req_events = poll_requested_events(wait);
__poll_t rc = 0;
if (req_events & (EPOLLOUT | EPOLLWRNORM | EPOLLIN | EPOLLRDNORM))
rc = v4l2_m2m_poll_for_data(file, m2m_ctx, wait);
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))
rc |= EPOLLPRI;
}
return rc;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_poll);