diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 4587a4c..0c0146e 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * ethtool.h: Defines for Linux ethtool.
  *