media: uvcvideo: Annotate lock requirements for uvc_ctrl_set

Make it explicit that the function is always called with ctrl_mutex
being held.

Suggested-by: Laurent Pinchart <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Ricardo Ribalda <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

Author: ribalda

drivers/media/usb/uvc/uvc_ctrl.c

@@ -1981,6 +1981,8 @@ int uvc_ctrl_set(struct uvc_fh *handle,
 	s32 max;
 	int ret;
 
+	lockdep_assert_held(&chain->ctrl_mutex);
+
 	if (__uvc_query_v4l2_class(chain, xctrl->id, 0) >= 0)
 		return -EACCES;