diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index 73da1f5..42204d6 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _BCACHE_BTREE_H
 #define _BCACHE_BTREE_H