diff --git a/include/linux/key.h b/include/linux/key.h
index ff10273..ae11773 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -361,6 +361,7 @@ extern void key_set_timeout(struct key *, unsigned);
 
 extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
 				 key_perm_t perm);
+extern void key_free_user_ns(struct user_namespace *);
 
 /*
  * The permissions required on a key that we're looking up.
@@ -434,6 +435,7 @@ extern void key_init(void);
 #define key_fsuid_changed(c)		do { } while(0)
 #define key_fsgid_changed(c)		do { } while(0)
 #define key_init()			do { } while(0)
+#define key_free_user_ns(ns)		do { } while(0)
 
 #endif /* CONFIG_KEYS */
 #endif /* __KERNEL__ */