diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index bec9caf..b2e05c4 100644
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * TCP Westwood+: end-to-end bandwidth estimation for TCP
  *