diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
index 9991688d7d1d..7b7a0456c15c 100644
--- a/net/ethtool/cabletest.c
+++ b/net/ethtool/cabletest.c
@@ -227,9 +227,9 @@ cable_test_tdr_act_policy[ETHTOOL_A_CABLE_TEST_TDR_MAX + 1] = {
 };
 
 /* CABLE_TEST_TDR_ACT */
-int ethnl_act_cable_test_tdr_cfg(const struct nlattr *nest,
-				 struct genl_info *info,
-				 struct phy_tdr_config *cfg)
+static int ethnl_act_cable_test_tdr_cfg(const struct nlattr *nest,
+					struct genl_info *info,
+					struct phy_tdr_config *cfg)
 {
 	struct nlattr *tb[ETHTOOL_A_CABLE_TEST_TDR_CFG_MAX + 1];
 	int ret;