This is a note to let you know that I've just added the patch titled
media: v4l2-mem2mem: prevent pollerr when last_buffer_dequeued is set
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-v4l2-mem2mem-prevent-pollerr-when-last_buffer_.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 095c273322857febffe75c06a6c27b8fe7ccb48d
Author: Ming Qian <ming.qian@xxxxxxx>
Date: Wed Jun 15 04:19:20 2022 +0100
media: v4l2-mem2mem: prevent pollerr when last_buffer_dequeued is set
[ Upstream commit d4de27a9b1eadd33a2e40de87a646d1bf5fef756 ]
If the last buffer was dequeued from the capture queue,
signal userspace. DQBUF(CAPTURE) will return -EPIPE.
But if output queue is empty and capture queue is empty,
v4l2_m2m_poll_for_data will return EPOLLERR,
This is very easy to happen in drain.
When last_buffer_dequeued is set, we shouldn't return EPOLLERR,
but return EPOLLIN | EPOLLRDNORM.
Fixes: 1698a7f151126 ("media: v4l2-mem2mem: simplify poll logic")
Signed-off-by: Ming Qian <ming.qian@xxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index 6469f9a25a4e..837e1855f94b 100644
--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -925,7 +925,7 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file,
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)))
+ (list_empty(&dst_q->queued_list) && !dst_q->last_buffer_dequeued)))
return EPOLLERR;
spin_lock_irqsave(&src_q->done_lock, flags);
