Re: [PATCH net-next] geneve: add rtnl changelink support

From: Girish Moodalbail <redacted>
Date: Mon, 15 May 2017 10:47:04 -0700

 	if (data[IFLA_GENEVE_REMOTE]) {
-		info.key.u.ipv4.dst =
+		info->key.u.ipv4.dst =
 			nla_get_in_addr(data[IFLA_GENEVE_REMOTE]);
 
-		if (IN_MULTICAST(ntohl(info.key.u.ipv4.dst))) {
+		if (IN_MULTICAST(ntohl(info->key.u.ipv4.dst))) {
 			netdev_dbg(dev, "multicast remote is unsupported\n");
 			return -EINVAL;
 		}
+		if (changelink &&
+		    ip_tunnel_info_af(&geneve->info) == AF_INET6) {
+			info->mode &= ~IP_TUNNEL_INFO_IPV6;
+			info->key.tun_flags &= ~TUNNEL_CSUM;
+			*use_udp6_rx_checksums = false;
+		}
 	}

I don't understand this "changelink" guarded code, why do you need to
clear all of this state out if the existing tunnel type if AF_INET6
and only when doing a changelink?

In any event, I think you need to add a comment explaining it.