bonding: fix the err path for dev hwaddr sync in bond_enslave

BugLink: http://bugs.launchpad.net/bugs/1765010

[ Upstream commit 5c78f6bf ]

vlan_vids_add_by_dev is called right after dev hwaddr sync, so on
the err path it should unsync dev hwaddr. Otherwise, the slave
dev's hwaddr will never be unsync when this err happens.

Fixes: 1ff412ad ("bonding: change the bond's vlan syncing functions with the standard ones")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/net/bonding/bond_main.c

@@ -1537,7 +1537,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	if (res) {
 		netdev_err(bond_dev, "Couldn't add bond vlan ids to %s\n",
 			   slave_dev->name);
-		goto err_close;
+		goto err_hwaddr_unsync;
 	}
 
 	prev_slave = bond_last_slave(bond);
@@ -1724,9 +1724,6 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	netdev_rx_handler_unregister(slave_dev);
 
 err_detach:
-	if (!bond_uses_primary(bond))
-		bond_hw_addr_flush(bond_dev, slave_dev);
-
 	vlan_vids_del_by_dev(slave_dev, bond_dev);
 	if (rcu_access_pointer(bond->primary_slave) == new_slave)
 		RCU_INIT_POINTER(bond->primary_slave, NULL);
@@ -1740,6 +1737,10 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	synchronize_rcu();
 	slave_disable_netpoll(new_slave);
 
+err_hwaddr_unsync:
+	if (!bond_uses_primary(bond))
+		bond_hw_addr_flush(bond_dev, slave_dev);
+
 err_close:
 	slave_dev->priv_flags &= ~IFF_BONDING;
 	dev_close(slave_dev);