[media] v4l: vb2: Avoid double WARN_ON when stopping streaming

The __vb2_queue_cancel function marks the queue as not streaming and
then WARNs when buffers are still owned by the driver. It proceeds to
complete all active buffers by calling vb2_buffer_done with the new
buffer state set to VB2_BUF_STATE_ERROR in that case. This triggers
another WARN_ON due to as new state not being VB2_BUF_STATE_QUEUED while
the queue is not streaming.

Check buffer ownership and complete all active buffers before marking
the queue as not streaming to avoid the double WARN_on.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/v4l2-core/videobuf2-core.c

@@ -2087,9 +2087,6 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 	 */
 	if (q->start_streaming_called)
 		call_void_qop(q, stop_streaming, q);
-	q->streaming = 0;
-	q->start_streaming_called = 0;
-	q->queued_count = 0;
 
 	if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
 		for (i = 0; i < q->num_buffers; ++i)
@@ -2099,6 +2096,10 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
 		WARN_ON(atomic_read(&q->owned_by_drv_count));
 	}
 
+	q->streaming = 0;
+	q->start_streaming_called = 0;
+	q->queued_count = 0;
+
 	/*
 	 * Remove all buffers from videobuf's list...
 	 */