diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 5ce9538..4397c52 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_STRING_HELPERS_H_
 #define _LINUX_STRING_HELPERS_H_