The following commit has been merged in the batman-adv/next branch: commit aa79e66eee5d525e2fcbd2a5fcb87ae3dd4aa9e9 Author: Pavel Emelyanov xemul@parallels.com Date: Wed Aug 8 21:53:19 2012 +0000

net: Make ifindex generation per-net namespace

Strictly speaking this is only _really_ required for checkpoint-restore to make loopback device always have the same index.

This change appears to be safe wrt "ifindex should be unique per-system" concept, as all the ifindex usage is either already made per net namespace of is explicitly limited with init_net only.

There are two cool side effects of this. The first one -- ifindices of devices in container are always small, regardless of how many containers we've started (and re-started) so far. The second one is -- we can speed up the loopback ifidex access as shown in the next patch.

v2: Place ifindex right after dev_base_seq : avoid two holes and use the same cache line, dirtied in list_netdevice()/unlist_netdevice()

Signed-off-by: Pavel Emelyanov xemul@parallels.com Acked-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index ae1cd6c..6dc3db3 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -66,6 +66,7 @@ struct net { struct hlist_head *dev_name_head; struct hlist_head *dev_index_head; unsigned int dev_base_seq; /* protected by rtnl_mutex */ + int ifindex;

/* core fib_rules */ struct list_head rules_ops; diff --git a/net/core/dev.c b/net/core/dev.c index 3ca300d..1f06df8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5221,12 +5221,12 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg) */ static int dev_new_index(struct net *net) { - static int ifindex; + int ifindex = net->ifindex; for (;;) { if (++ifindex <= 0) ifindex = 1; if (!__dev_get_by_index(net, ifindex)) - return ifindex; + return net->ifindex = ifindex; } }