diff --git a/include/uapi/linux/usbdevice_fs.h b/include/uapi/linux/usbdevice_fs.h
index 0c65e4b..cbf122d 100644
--- a/include/uapi/linux/usbdevice_fs.h
+++ b/include/uapi/linux/usbdevice_fs.h
@@ -102,7 +102,10 @@
 	int buffer_length;
 	int actual_length;
 	int start_frame;
-	int number_of_packets;
+	union {
+		int number_of_packets;	/* Only used for isoc urbs */
+		unsigned int stream_id;	/* Only used with bulk streams */
+	};
 	int error_count;
 	unsigned int signr;	/* signal to be sent on completion,
 				  or 0 if none should be sent. */