[NETNS]: Add netns parameter to inetdev_by_index.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 8b81deb..a74983d 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -1193,7 +1193,8 @@
 {
 	struct ip_tunnel *t = netdev_priv(dev);
 	if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
-		struct in_device *in_dev = inetdev_by_index(t->mlink);
+		struct in_device *in_dev;
+		in_dev = inetdev_by_index(dev->nd_net, t->mlink);
 		if (in_dev) {
 			ip_mc_dec_group(in_dev, t->parms.iph.daddr);
 			in_dev_put(in_dev);