If the returned size of the query does not match the expected size or it
is zero, return -EPIPE instead of 0 or a positive value.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 497073a50194..902f2817a743 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -83,7 +83,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
 		dev_err(&dev->udev->dev,
 			"Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",
 			uvc_query_name(query), cs, unit, ret, size);
-		return ret;
+		return ret < 0 ? ret : -EPIPE;
 	}
 
 	/* reuse data[0] to request the error code. */

-- 
b4 0.11.0-dev-d93f8