bridge: notify applications if address of bridge device changes

The mac address of the bridge device may be changed when a new interface
is added to the bridge. If this happens, then the bridge needs to call
the network notifiers to tickle any other systems that care. Since bridge
can be a module, this also means exporting the notifier function.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index dce8f00..718b603 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -389,6 +389,7 @@
 {
 	struct net_bridge_port *p;
 	int err = 0;
+	bool changed_addr;
 
 	/* Don't allow bridging non-ethernet like devices */
 	if ((dev->flags & IFF_LOOPBACK) ||
@@ -446,7 +447,7 @@
 	list_add_rcu(&p->list, &br->port_list);
 
 	spin_lock_bh(&br->lock);
-	br_stp_recalculate_bridge_id(br);
+	changed_addr = br_stp_recalculate_bridge_id(br);
 	br_features_recompute(br);
 
 	if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
@@ -456,6 +457,9 @@
 
 	br_ifinfo_notify(RTM_NEWLINK, p);
 
+	if (changed_addr)
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+
 	dev_set_mtu(br->dev, br_min_mtu(br));
 
 	kobject_uevent(&p->kobj, KOBJ_ADD);