diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 03082e1..bf41492 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -1094,7 +1094,7 @@ static void metadata_update_cancel(struct mddev *mddev)
 /*
  * return 0 if all the bitmaps have the same sync_size
  */
-int cluster_check_sync_size(struct mddev *mddev)
+static int cluster_check_sync_size(struct mddev *mddev)
 {
 	int i, rv;
 	bitmap_super_t *sb;