net: dsa: be mostly no-op in dsa_slave_set_mac_address when down

Since the slave unicast address is synced to hardware and to the DSA
master during dsa_slave_open(), this means that a call to
dsa_slave_set_mac_address() while the slave interface is down will
result to a call to dsa_port_standalone_host_fdb_del() and to
dev_uc_del() for the MAC address while there was no previous
dsa_port_standalone_host_fdb_add() or dev_uc_add().

This is a partial revert of the blamed commit below, which was too
aggressive.

Fixes: 35aae5ab9121 ("net: dsa: remove workarounds for changing master promisc/allmulti only while up")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 42436ac..a61a7c5 100644 (file)
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -305,6 +305,12 @@ static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;
 
+       /* If the port is down, the address isn't synced yet to hardware or
+        * to the DSA master, so there is nothing to change.
+        */
+       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)
@@ -323,6 +329,7 @@ static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
        if (dsa_switch_supports_uc_filtering(ds))
                dsa_port_standalone_host_fdb_del(dp, dev->dev_addr, 0);
 
+out_change_dev_addr:
        eth_hw_addr_set(dev, addr->sa_data);
 
        return 0;