media: allegro: warn if response message has an unexpected size

The driver uses structs to parse the responses from the VCU and expects
a certain size of the responses. However, the size and format of the
mails is not stable across firmware versions. Therefore, print a warning
if the size does not match the expected size to warn the user that
strange things might happen.
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/allegro-dvt/allegro-core.c

@@ -1711,6 +1711,12 @@ allegro_handle_create_channel(struct allegro_dev *dev,
 	struct allegro_channel *channel;
 	int err = 0;
 
+	if (msg->header.length != sizeof(*msg) - sizeof(msg->header))
+		v4l2_warn(&dev->v4l2_dev,
+			  "received message has %d bytes, but expected %zu\n",
+			  msg->header.length,
+			  sizeof(*msg) - sizeof(msg->header));
+
 	channel = allegro_find_channel_by_user_id(dev, msg->user_id);
 	if (IS_ERR(channel)) {
 		v4l2_warn(&dev->v4l2_dev,
@@ -1804,6 +1810,12 @@ allegro_handle_encode_frame(struct allegro_dev *dev,
 {
 	struct allegro_channel *channel;
 
+	if (msg->header.length != sizeof(*msg) - sizeof(msg->header))
+		v4l2_warn(&dev->v4l2_dev,
+			  "received message has %d bytes, but expected %zu\n",
+			  msg->header.length,
+			  sizeof(*msg) - sizeof(msg->header));
+
 	channel = allegro_find_channel_by_channel_id(dev, msg->channel_id);
 	if (IS_ERR(channel)) {
 		v4l2_err(&dev->v4l2_dev,