commit 7da7dfcb787d77929c15d5b7127c816ee16f1ede
Author: Tom Goff <thomas.goff@boeing.com>
Date:   Fri Dec 16 17:39:00 2011 -0800

    Make network device ifindex sequential per network namespace.

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 3bb6fa0..2fd53da 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -62,6 +62,8 @@ struct net {
 	struct sock 		*rtnl;			/* rtnetlink socket */
 	struct sock		*genl_sock;
 
+	int ifindex;
+
 	struct list_head 	dev_base_head;
 	struct hlist_head 	*dev_name_head;
 	struct hlist_head	*dev_index_head;
diff --git a/net/core/dev.c b/net/core/dev.c
index 6ba50a1..ba95aa5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5260,12 +5260,11 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
  */
 static int dev_new_index(struct net *net)
 {
-	static int ifindex;
 	for (;;) {
-		if (++ifindex <= 0)
-			ifindex = 1;
-		if (!__dev_get_by_index(net, ifindex))
-			return ifindex;
+		if (++net->ifindex <= 0)
+			net->ifindex = 1;
+		if (!__dev_get_by_index(net, net->ifindex))
+			return net->ifindex;
 	}
 }
 
@@ -6277,8 +6276,8 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	/* Actually switch the network namespace */
 	dev_net_set(dev, net);
 
-	/* If there is an ifindex conflict assign a new one */
-	if (__dev_get_by_index(net, dev->ifindex)) {
+	/* Assign a new ifindex */
+	{
 		int iflink = (dev->iflink == dev->ifindex);
 		dev->ifindex = dev_new_index(net);
 		if (iflink)