net: ethtool: optionally skip rtnl_lock in cable test handlers

Skip rtnl_lock in cable test handlers. This is really a noop since
no ops locked device supports these.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260605002912.3456868-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/ethtool/cabletest.c

@@ -73,8 +73,7 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 
 	dev = req_info.dev;
 
-	rtnl_lock();
-	netdev_lock_ops(dev);
+	netdev_lock_ops_compat(dev);
 	phydev = ethnl_req_get_phydev(&req_info, tb,
 				      ETHTOOL_A_CABLE_TEST_HEADER,
 				      info->extack);
@@ -101,8 +100,7 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 		ethnl_cable_test_started(phydev, ETHTOOL_MSG_CABLE_TEST_NTF);
 
 out_unlock:
-	netdev_unlock_ops(dev);
-	rtnl_unlock();
+	netdev_unlock_ops_compat(dev);
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;
 }
@@ -342,8 +340,7 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info)
 	if (ret)
 		goto out_dev_put;
 
-	rtnl_lock();
-	netdev_lock_ops(dev);
+	netdev_lock_ops_compat(dev);
 	phydev = ethnl_req_get_phydev(&req_info, tb,
 				      ETHTOOL_A_CABLE_TEST_TDR_HEADER,
 				      info->extack);
@@ -371,8 +368,7 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info)
 					 ETHTOOL_MSG_CABLE_TEST_TDR_NTF);
 
 out_unlock:
-	netdev_unlock_ops(dev);
-	rtnl_unlock();
+	netdev_unlock_ops_compat(dev);
 out_dev_put:
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;