ip6_tunnel: Use ip6_tnl_dev_init as the ndo_init function.

commit 6c6151da upstream.

ip6_tnl_dev_init() sets the dev->iflink via a call to
ip6_tnl_link_config(). After that, register_netdevice()
sets dev->iflink = -1. So we loose the iflink configuration
for ipv6 tunnels. Fix this by using ip6_tnl_dev_init() as the
ndo_init function. Then ip6_tnl_dev_init() is called after
dev->iflink is set to -1 from register_netdevice().
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/ipv6/ip6_tunnel.c

@@ -272,9 +272,6 @@ static int ip6_tnl_create2(struct net_device *dev)
 	int err;
 
 	t = netdev_priv(dev);
-	err = ip6_tnl_dev_init(dev);
-	if (err < 0)
-		goto out;
 
 	err = register_netdevice(dev);
 	if (err < 0)
@@ -1456,6 +1453,7 @@ ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
 
 
 static const struct net_device_ops ip6_tnl_netdev_ops = {
+	.ndo_init	= ip6_tnl_dev_init,
 	.ndo_uninit	= ip6_tnl_dev_uninit,
 	.ndo_start_xmit = ip6_tnl_xmit,
 	.ndo_do_ioctl	= ip6_tnl_ioctl,
@@ -1540,16 +1538,10 @@ static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
 	struct ip6_tnl *t = netdev_priv(dev);
 	struct net *net = dev_net(dev);
 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
-	int err = ip6_tnl_dev_init_gen(dev);
-
-	if (err)
-		return err;
 
 	t->parms.proto = IPPROTO_IPV6;
 	dev_hold(dev);
 
-	ip6_tnl_link_config(t);
-
 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
 	return 0;
 }