Re: [PATCH v3 net 1/5] ipv6: Refactor common ip6gre_tunnel_init codes

On Fri, Sep 11, 2015 at 03:30:59PM -0700, David Miller wrote:

From: Martin KaFai Lau <redacted>
Date: Fri, 11 Sep 2015 11:06:17 -0700

quoted

@@ -1460,19 +1474,16 @@ static void ip6gre_netlink_parms(struct nlattr *data[],
 static int ip6gre_tap_init(struct net_device *dev)
 {
 	struct ip6_tnl *tunnel;
+	int ret;

-	tunnel = netdev_priv(dev);
+	ret = ip6gre_tunnel_init_common(dev);
+	if (ret)
+		return ret;

-	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
-	strcpy(tunnel->parms.name, dev->name);
+	tunnel = netdev_priv(dev);

 	ip6gre_tnl_link_config(tunnel, 1);

-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	return 0;
 }

Is this really equivalent?

The existing code for GRE tap device initialization would use whatever
ether_setup() left in the broadcast address, it would leave
dev->dev_addr alone, and unconditionally use eth_header_ops.

The new ip6gre_tunnel_init_common() does not set the dev->dev_addr
or dev->header_ops.  The change in ip6gre_tap_init() is to initialize
dev->tstats before ip6gre_tnl_link_config().

or I am missing something and have overlooked a bug?

Thanks,
Martin