diff options
| author | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2021-06-30 09:58:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-08-15 12:59:54 +0200 |
| commit | 0dd09c612e0b05f4516079957cd3a8de75f54199 (patch) | |
| tree | dc0e9a3ddbdb48d5094bf4782f8bae6dc48b0701 /drivers/media | |
| parent | 1991e00436b7db31bc99640b26d0ee0e3ef2c235 (diff) | |
media: videobuf2-core: dequeue if start_streaming fails
[ Upstream commit c592b46907adbeb81243f7eb7a468c36692658b8 ]
If a vb2_queue sets q->min_buffers_needed then when the number of
queued buffers reaches q->min_buffers_needed, vb2_core_qbuf() will call
the start_streaming() callback. If start_streaming() returns an error,
then that error was just returned by vb2_core_qbuf(), but the buffer
was still queued. However, userspace expects that if VIDIOC_QBUF fails,
the buffer is returned dequeued.
So if start_streaming() fails, then remove the buffer from the queue,
thus avoiding this unwanted side-effect.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Fixes: b3379c6201bb ("[media] vb2: only call start_streaming if sufficient buffers are queued")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-core.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index e0041fcfa783..c1faa1332e32 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1361,6 +1361,7 @@ static int vb2_start_streaming(struct vb2_queue *q) int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb) { struct vb2_buffer *vb; + enum vb2_buffer_state orig_state; int ret; if (q->error) { @@ -1390,6 +1391,7 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb) * Add to the queued buffers list, a buffer will stay on it until * dequeued in dqbuf. */ + orig_state = vb->state; list_add_tail(&vb->queued_entry, &q->queued_list); q->queued_count++; q->waiting_for_buffers = false; @@ -1420,8 +1422,17 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb) if (q->streaming && !q->start_streaming_called && q->queued_count >= q->min_buffers_needed) { ret = vb2_start_streaming(q); - if (ret) + if (ret) { + /* + * Since vb2_core_qbuf will return with an error, + * we should return it to state DEQUEUED since + * the error indicates that the buffer wasn't queued. + */ + list_del(&vb->queued_entry); + q->queued_count--; + vb->state = orig_state; return ret; + } } dprintk(1, "qbuf of buffer %d succeeded\n", vb->index); |