net: dsa: deduplicate code adding / deleting the port address to fdb

The sequence
  if (dsa_switch_supports_uc_filtering(ds))
    dsa_port_standalone_host_fdb_add(dp, addr, 0);
  if (!ether_addr_equal(addr, conduit->dev_addr))
    dev_uc_add(conduit, addr);
is executed both in dsa_user_open() and dsa_user_set_mac_addr().

Its reverse is executed both in dsa_user_close() and
dsa_user_set_mac_addr().

Refactor these sequences into new functions dsa_user_host_uc_install()
and dsa_user_host_uc_uninstall().
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/user.c

@@ -355,60 +355,82 @@ static int dsa_user_get_iflink(const struct net_device *dev)
 	return READ_ONCE(dsa_user_to_conduit(dev)->ifindex);
 }
 
-static int dsa_user_open(struct net_device *dev)
+static int dsa_user_host_uc_install(struct net_device *dev, const u8 *addr)
 {
 	struct net_device *conduit = dsa_user_to_conduit(dev);
 	struct dsa_port *dp = dsa_user_to_port(dev);
 	struct dsa_switch *ds = dp->ds;
 	int err;
 
-	err = dev_open(conduit, NULL);
-	if (err < 0) {
-		netdev_err(dev, "failed to open conduit %s\n", conduit->name);
-		goto out;
-	}
-
 	if (dsa_switch_supports_uc_filtering(ds)) {
-		err = dsa_port_standalone_host_fdb_add(dp, dev->dev_addr, 0);
+		err = dsa_port_standalone_host_fdb_add(dp, addr, 0);
 		if (err)
 			goto out;
 	}
 
-	if (!ether_addr_equal(dev->dev_addr, conduit->dev_addr)) {
-		err = dev_uc_add(conduit, dev->dev_addr);
+	if (!ether_addr_equal(addr, conduit->dev_addr)) {
+		err = dev_uc_add(conduit, addr);
 		if (err < 0)
 			goto del_host_addr;
 	}
 
-	err = dsa_port_enable_rt(dp, dev->phydev);
-	if (err)
-		goto del_unicast;
-
 	return 0;
 
-del_unicast:
-	if (!ether_addr_equal(dev->dev_addr, conduit->dev_addr))
-		dev_uc_del(conduit, dev->dev_addr);
 del_host_addr:
 	if (dsa_switch_supports_uc_filtering(ds))
-		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
+		dsa_port_standalone_host_fdb_del(dp, addr, 0);
 out:
 	return err;
 }
 
-static int dsa_user_close(struct net_device *dev)
+static void dsa_user_host_uc_uninstall(struct net_device *dev)
 {
 	struct net_device *conduit = dsa_user_to_conduit(dev);
 	struct dsa_port *dp = dsa_user_to_port(dev);
 	struct dsa_switch *ds = dp->ds;
 
-	dsa_port_disable_rt(dp);
-
 	if (!ether_addr_equal(dev->dev_addr, conduit->dev_addr))
 		dev_uc_del(conduit, dev->dev_addr);
 
 	if (dsa_switch_supports_uc_filtering(ds))
 		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
+}
+
+static int dsa_user_open(struct net_device *dev)
+{
+	struct net_device *conduit = dsa_user_to_conduit(dev);
+	struct dsa_port *dp = dsa_user_to_port(dev);
+	int err;
+
+	err = dev_open(conduit, NULL);
+	if (err < 0) {
+		netdev_err(dev, "failed to open conduit %s\n", conduit->name);
+		goto out;
+	}
+
+	err = dsa_user_host_uc_install(dev, dev->dev_addr);
+	if (err)
+		goto out;
+
+	err = dsa_port_enable_rt(dp, dev->phydev);
+	if (err)
+		goto out_del_host_uc;
+
+	return 0;
+
+out_del_host_uc:
+	dsa_user_host_uc_uninstall(dev);
+out:
+	return err;
+}
+
+static int dsa_user_close(struct net_device *dev)
+{
+	struct dsa_port *dp = dsa_user_to_port(dev);
+
+	dsa_port_disable_rt(dp);
+
+	dsa_user_host_uc_uninstall(dev);
 
 	return 0;
 }
@@ -448,7 +470,6 @@ static void dsa_user_set_rx_mode(struct net_device *dev)
 
 static int dsa_user_set_mac_address(struct net_device *dev, void *a)
 {
-	struct net_device *conduit = dsa_user_to_conduit(dev);
 	struct dsa_port *dp = dsa_user_to_port(dev);
 	struct dsa_switch *ds = dp->ds;
 	struct sockaddr *addr = a;
@@ -470,34 +491,16 @@ static int dsa_user_set_mac_address(struct net_device *dev, void *a)
 	if (!(dev->flags & IFF_UP))
 		goto out_change_dev_addr;
 
-	if (dsa_switch_supports_uc_filtering(ds)) {
-		err = dsa_port_standalone_host_fdb_add(dp, addr->sa_data, 0);
+	err = dsa_user_host_uc_install(dev, addr->sa_data);
 	if (err)
 		return err;
-	}
-
-	if (!ether_addr_equal(addr->sa_data, conduit->dev_addr)) {
-		err = dev_uc_add(conduit, addr->sa_data);
-		if (err < 0)
-			goto del_unicast;
-	}
 
-	if (!ether_addr_equal(dev->dev_addr, conduit->dev_addr))
-		dev_uc_del(conduit, dev->dev_addr);
-
-	if (dsa_switch_supports_uc_filtering(ds))
-		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
+	dsa_user_host_uc_uninstall(dev);
 
 out_change_dev_addr:
 	eth_hw_addr_set(dev, addr->sa_data);
 
 	return 0;
-
-del_unicast:
-	if (dsa_switch_supports_uc_filtering(ds))
-		dsa_port_standalone_host_fdb_del(dp, addr->sa_data, 0);
-
-	return err;
 }
 
 struct dsa_user_dump_ctx {