net: dsa: install the primary unicast MAC address as standalone port host FDB

To be able to safely turn off CPU flooding for standalone ports, we need
to ensure that the dev_addr of each DSA slave interface is installed as
a standalone host FDB entry for compatible switches.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/slave.c

@@ -175,6 +175,7 @@ static int dsa_slave_open(struct net_device *dev)
 {
 	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
 	int err;
 
 	err = dev_open(master, NULL);
@@ -183,10 +184,16 @@ static int dsa_slave_open(struct net_device *dev)
 		goto out;
 	}
 
+	if (dsa_switch_supports_uc_filtering(ds)) {
+		err = dsa_port_standalone_host_fdb_add(dp, dev->dev_addr, 0);
+		if (err)
+			goto out;
+	}
+
 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr)) {
 		err = dev_uc_add(master, dev->dev_addr);
 		if (err < 0)
-			goto out;
+			goto del_host_addr;
 	}
 
 	err = dsa_port_enable_rt(dp, dev->phydev);
@@ -198,6 +205,9 @@ static int dsa_slave_open(struct net_device *dev)
 del_unicast:
 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
 		dev_uc_del(master, dev->dev_addr);
+del_host_addr:
+	if (dsa_switch_supports_uc_filtering(ds))
+		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
 out:
 	return err;
 }
@@ -206,12 +216,16 @@ static int dsa_slave_close(struct net_device *dev)
 {
 	struct net_device *master = dsa_slave_to_master(dev);
 	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
 
 	dsa_port_disable_rt(dp);
 
 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
 		dev_uc_del(master, dev->dev_addr);
 
+	if (dsa_switch_supports_uc_filtering(ds))
+		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
+
 	return 0;
 }
 
@@ -244,24 +258,41 @@ static void dsa_slave_set_rx_mode(struct net_device *dev)
 static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
 {
 	struct net_device *master = dsa_slave_to_master(dev);
+	struct dsa_port *dp = dsa_slave_to_port(dev);
+	struct dsa_switch *ds = dp->ds;
 	struct sockaddr *addr = a;
 	int err;
 
 	if (!is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 
+	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, master->dev_addr)) {
 		err = dev_uc_add(master, addr->sa_data);
 		if (err < 0)
-			return err;
+			goto del_unicast;
 	}
 
 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
 		dev_uc_del(master, dev->dev_addr);
 
+	if (dsa_switch_supports_uc_filtering(ds))
+		dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
+
 	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_slave_dump_ctx {