[NET]: Make rtnetlink infrastructure network namespace aware (v3)

After this patch none of the netlink callback support anything
except the initial network namespace but the rtnetlink infrastructure
now handles multiple network namespaces.

Changes from v2:
- IPv6 addrlabel processing

Changes from v1:
- no need for special rtnl_unlock handling
- fixed IPv6 ndisc

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 9425684..39c89c6 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -793,10 +793,10 @@
 		kfree_skb(skb);
 		goto errout;
 	}
-	err = rtnl_notify(skb, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
+	err = rtnl_notify(skb, &init_net, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
 errout:
 	if (err < 0)
-		rtnl_set_sk_err(RTNLGRP_DECnet_IFADDR, err);
+		rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_IFADDR, err);
 }
 
 static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)