macvlan: fix gso_max_size setting

gso_max_size must be set based on the value of the underlying device to
support devices not using the full 64k.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -360,6 +360,7 @@ static int macvlan_init(struct net_device *dev)
 	dev->state		= (dev->state & ~MACVLAN_STATE_MASK) |
 				  (lowerdev->state & MACVLAN_STATE_MASK);
 	dev->features 		= lowerdev->features & MACVLAN_FEATURES;
+	dev->gso_max_size	= lowerdev->gso_max_size;
 	dev->iflink		= lowerdev->ifindex;
 	dev->hard_header_len	= lowerdev->hard_header_len;
 
@@ -596,6 +597,7 @@ static int macvlan_device_event(struct notifier_block *unused,
 	case NETDEV_FEAT_CHANGE:
 		list_for_each_entry(vlan, &port->vlans, list) {
 			vlan->dev->features = dev->features & MACVLAN_FEATURES;
+			vlan->dev->gso_max_size = dev->gso_max_size;
 			netdev_features_change(vlan->dev);
 		}
 		break;