net: dsa: mv88e6xxx: fix duplicate vlan warning

When setting VLANs on DSA switches, the VLAN is added to both the port
concerned as well as the CPU port by dsa_slave_vlan_add(), as well as
any DSA ports.  If multiple ports are configured with the same VLAN ID,
this triggers a warning on the CPU and DSA ports.

Avoid this warning for CPU and DSA ports.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -1795,7 +1795,7 @@ static int mv88e6xxx_broadcast_setup(struct mv88e6xxx_chip *chip, u16 vid)
 }
 
 static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
-				    u16 vid, u8 member)
+				    u16 vid, u8 member, bool warn)
 {
 	const u8 non_member = MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_NON_MEMBER;
 	struct mv88e6xxx_vtu_entry vlan;
@@ -1840,7 +1840,7 @@ static int mv88e6xxx_port_vlan_join(struct mv88e6xxx_chip *chip, int port,
 		err = mv88e6xxx_vtu_loadpurge(chip, &vlan);
 		if (err)
 			return err;
-	} else {
+	} else if (warn) {
 		dev_info(chip->dev, "p%d: already a member of VLAN %d\n",
 			 port, vid);
 	}
@@ -1854,6 +1854,7 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 	struct mv88e6xxx_chip *chip = ds->priv;
 	bool untagged = vlan->flags & BRIDGE_VLAN_INFO_UNTAGGED;
 	bool pvid = vlan->flags & BRIDGE_VLAN_INFO_PVID;
+	bool warn;
 	u8 member;
 	u16 vid;
 
@@ -1867,10 +1868,15 @@ static void mv88e6xxx_port_vlan_add(struct dsa_switch *ds, int port,
 	else
 		member = MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_TAGGED;
 
+	/* net/dsa/slave.c will call dsa_port_vlan_add() for the affected port
+	 * and then the CPU port. Do not warn for duplicates for the CPU port.
+	 */
+	warn = !dsa_is_cpu_port(ds, port) && !dsa_is_dsa_port(ds, port);
+
 	mv88e6xxx_reg_lock(chip);
 
 	for (vid = vlan->vid_begin; vid <= vlan->vid_end; ++vid)
-		if (mv88e6xxx_port_vlan_join(chip, port, vid, member))
+		if (mv88e6xxx_port_vlan_join(chip, port, vid, member, warn))
 			dev_err(ds->dev, "p%d: failed to add VLAN %d%c\n", port,
 				vid, untagged ? 'u' : 't');