Merge branch 'fix-changing-dsa-conduit'

Marek Behún says:

====================
Fix changing DSA conduit

This series fixes an issue in the DSA code related to host interface UC
address installed into port FDB and port conduit address database when
live-changing port conduit.

The first patch refactores/deduplicates the installation/uninstallation
of the interface's MAC address and the second patch fixes the issue.

Cover letter for v1 and v2:
  https://patchwork.kernel.org/project/netdevbpf/cover/20240429163627.16031-1-kabel@kernel.org/
  https://patchwork.kernel.org/project/netdevbpf/cover/20240502122922.28139-1-kabel@kernel.org/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/port.c

@@ -1467,10 +1467,34 @@ int dsa_port_change_conduit(struct dsa_port *dp, struct net_device *conduit,
 	 */
 	dsa_user_unsync_ha(dev);
 
+	/* If live-changing, we also need to uninstall the user device address
+	 * from the port FDB and the conduit interface.
+	 */
+	if (dev->flags & IFF_UP)
+		dsa_user_host_uc_uninstall(dev);
+
 	err = dsa_port_assign_conduit(dp, conduit, extack, true);
 	if (err)
 		goto rewind_old_addrs;
 
+	/* If the port doesn't have its own MAC address and relies on the DSA
+	 * conduit's one, inherit it again from the new DSA conduit.
+	 */
+	if (is_zero_ether_addr(dp->mac))
+		eth_hw_addr_inherit(dev, conduit);
+
+	/* If live-changing, we need to install the user device address to the
+	 * port FDB and the conduit interface.
+	 */
+	if (dev->flags & IFF_UP) {
+		err = dsa_user_host_uc_install(dev, dev->dev_addr);
+		if (err) {
+			NL_SET_ERR_MSG_MOD(extack,
+					   "Failed to install host UC address");
+			goto rewind_addr_inherit;
+		}
+	}
+
 	dsa_user_sync_ha(dev);
 
 	if (vlan_filtering) {
@@ -1500,10 +1524,26 @@ int dsa_port_change_conduit(struct dsa_port *dp, struct net_device *conduit,
 rewind_new_addrs:
 	dsa_user_unsync_ha(dev);
 
+	if (dev->flags & IFF_UP)
+		dsa_user_host_uc_uninstall(dev);
+
+rewind_addr_inherit:
+	if (is_zero_ether_addr(dp->mac))
+		eth_hw_addr_inherit(dev, old_conduit);
+
 	dsa_port_assign_conduit(dp, old_conduit, NULL, false);
 
 /* Restore the objects on the old CPU port */
 rewind_old_addrs:
+	if (dev->flags & IFF_UP) {
+		tmp = dsa_user_host_uc_install(dev, dev->dev_addr);
+		if (tmp) {
+			dev_err(ds->dev,
+				"port %d failed to restore host UC address: %pe\n",
+				dp->index, ERR_PTR(tmp));
+		}
+	}
+
 	dsa_user_sync_ha(dev);
 
 	if (vlan_filtering) {

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)
+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)
+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);
-		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;
-	}
+	err = dsa_user_host_uc_install(dev, addr->sa_data);
+	if (err)
+		return err;
 
-	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 {
@@ -2879,12 +2882,6 @@ int dsa_user_change_conduit(struct net_device *dev, struct net_device *conduit,
 			    ERR_PTR(err));
 	}
 
-	/* If the port doesn't have its own MAC address and relies on the DSA
-	 * conduit's one, inherit it again from the new DSA conduit.
-	 */
-	if (is_zero_ether_addr(dp->mac))
-		eth_hw_addr_inherit(dev, conduit);
-
 	return 0;
 
 out_revert_conduit_link:

net/dsa/user.h

@@ -42,6 +42,8 @@ int dsa_user_suspend(struct net_device *user_dev);
 int dsa_user_resume(struct net_device *user_dev);
 int dsa_user_register_notifier(void);
 void dsa_user_unregister_notifier(void);
+int dsa_user_host_uc_install(struct net_device *dev, const u8 *addr);
+void dsa_user_host_uc_uninstall(struct net_device *dev);
 void dsa_user_sync_ha(struct net_device *dev);
 void dsa_user_unsync_ha(struct net_device *dev);
 void dsa_user_setup_tagger(struct net_device *user);