diff --git a/vp8/encoder/ratectrl.c b/vp8/encoder/ratectrl.c
index cc3c82e74..e8e9c2c31 100644
--- a/vp8/encoder/ratectrl.c
+++ b/vp8/encoder/ratectrl.c
@@ -103,7 +103,7 @@ int vp8_gfboost_qadjust(int qindex) {
   return retval;
 }
 
-int kfboost_qadjust(int qindex) {
+static int kfboost_qadjust(int qindex) {
   int retval;
   double q;