diff --git a/net/ceph/buffer.c b/net/ceph/buffer.c
index add5f92..5622763 100644
--- a/net/ceph/buffer.c
+++ b/net/ceph/buffer.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 #include <linux/ceph/ceph_debug.h>