diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 0b1cabc..0e4d935 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -166,7 +166,7 @@ static int self_check_in_pq(const struct ubi_device *ubi,
  *  @ubi: UBI device description object
  *  @pnum: the to be checked PEB
  */
-int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
+static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
 {
 	int i;