[NETNS]: Create ipv6 devconf-s for namespaces

This is the core. Declare and register the pernet subsys for
addrconf. The init callback the will create the devconf-s.

The init_net will reuse the existing statically declared confs,
so that accessing them from inside the ipv6 code will still
work.

The register_pernet_subsys() is moved above the ipv6_add_dev()
call for loopback, because this function will need the
net->devconf_dflt pointer to be already set.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 10733a6..06b4dc0 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -28,5 +28,7 @@
 
 struct netns_ipv6 {
 	struct netns_sysctl_ipv6 sysctl;
+	struct ipv6_devconf	*devconf_all;
+	struct ipv6_devconf	*devconf_dflt;
 };
 #endif