diff --git a/COPYING b/COPYING
index 253bae48ea8..857d098a147 100644
--- a/COPYING
+++ b/COPYING
@@ -32,6 +32,10 @@ Files: src/include/ceph_hash.cc
 Copyright: None
 License: Public domain
 
+Files: src/include/rados.h, except ceph_stable_mod(), which is public domain
+Copyright: the authors
+License: LGPL-2.1 or LGPL-3 (see COPYING-LGPL2.1 and COPYING-LGPL3)
+
 Files: src/common/bloom_filter.hpp
 Copyright: Copyright (C) 2000 Arash Partow <arash@partow.net>
 License: Boost Software License, Version 1.0
diff --git a/src/include/rados.h b/src/include/rados.h
index 17871737801..14846577172 100644
--- a/src/include/rados.h
+++ b/src/include/rados.h
@@ -90,6 +90,8 @@ struct ceph_pg {
  *
  * b <= bmask and bmask=(2**n)-1
  * e.g., b=12 -> bmask=15, b=123 -> bmask=127
+ *
+ * ** This function is released to the public domain by the author. **
  */
 static inline int ceph_stable_mod(int x, int b, int bmask)
 {