vlan: Propagate MAC address to VLANs

The MAC address of the physical interface is only copied to the VLAN
when it is first created, resulting in an inconsistency after MAC
address changes of only newly created VLANs having an up-to-date MAC.

The VLANs should continue inheriting the MAC address of the physical
interface until the VLAN MAC address is explicitly set to any value.
This allows IPv6 EUI64 addresses for the VLAN to reflect any changes
to the MAC of the physical interface and thus for DAD to behave as
expected.

Signed-off-by: Mike Manning <mmanning@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index e7e6257..86ae75b 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -245,6 +245,17 @@
 	strncpy(result, vlan_dev_priv(dev)->real_dev->name, 23);
 }
 
+bool vlan_dev_inherit_address(struct net_device *dev,
+			      struct net_device *real_dev)
+{
+	if (dev->addr_assign_type != NET_ADDR_STOLEN)
+		return false;
+
+	ether_addr_copy(dev->dev_addr, real_dev->dev_addr);
+	call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+	return true;
+}
+
 static int vlan_dev_open(struct net_device *dev)
 {
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
@@ -255,7 +266,8 @@
 	    !(vlan->flags & VLAN_FLAG_LOOSE_BINDING))
 		return -ENETDOWN;
 
-	if (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr)) {
+	if (!ether_addr_equal(dev->dev_addr, real_dev->dev_addr) &&
+	    !vlan_dev_inherit_address(dev, real_dev)) {
 		err = dev_uc_add(real_dev, dev->dev_addr);
 		if (err < 0)
 			goto out;
@@ -560,8 +572,10 @@
 	/* ipv6 shared card related stuff */
 	dev->dev_id = real_dev->dev_id;
 
-	if (is_zero_ether_addr(dev->dev_addr))
-		eth_hw_addr_inherit(dev, real_dev);
+	if (is_zero_ether_addr(dev->dev_addr)) {
+		ether_addr_copy(dev->dev_addr, real_dev->dev_addr);
+		dev->addr_assign_type = NET_ADDR_STOLEN;
+	}
 	if (is_zero_ether_addr(dev->broadcast))
 		memcpy(dev->broadcast, real_dev->broadcast, dev->addr_len);