media: uvcvideo: Fix .queue_setup() to check the number of planes

According to documentation of struct vb2_ops the .queue_setup() callback
should return an error if the number of planes parameter contains an
invalid value on input. Fix this instead of ignoring the value.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/uvc/uvc_queue.c

@@ -82,9 +82,14 @@ static int uvc_queue_setup(struct vb2_queue *vq,
 	struct uvc_streaming *stream = uvc_queue_to_stream(queue);
 	unsigned size = stream->ctrl.dwMaxVideoFrameSize;
 
-	/* Make sure the image size is large enough. */
+	/*
+	 * When called with plane sizes, validate them. The driver supports
+	 * single planar formats only, and requires buffers to be large enough
+	 * to store a complete frame.
+	 */
 	if (*nplanes)
-		return sizes[0] < size ? -EINVAL : 0;
+		return *nplanes != 1 || sizes[0] < size ? -EINVAL : 0;
+
 	*nplanes = 1;
 	sizes[0] = size;
 	return 0;