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@xxxxxxxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-mem2mem.c | 47 +++++++++++++++-----------
1 file changed, 27 insertions(+), 20 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index 4f5176702937..f18fdce31d6f 100644
--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -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(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(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);
--
2.20.1
