diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index ce226c1..1f23161 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1169,9 +1169,9 @@
  *	ignoring pure split nodes) will be scanned.
  */
 
-void fib6_clean_tree(struct fib6_node *root,
-		     int (*func)(struct rt6_info *, void *arg),
-		     int prune, void *arg)
+static void fib6_clean_tree(struct fib6_node *root,
+			    int (*func)(struct rt6_info *, void *arg),
+			    int prune, void *arg)
 {
 	struct fib6_cleaner_t c;