From patchwork Thu Aug 9 07:53:19 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Emelyanov X-Patchwork-Id: 176016 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 412532C00DA for ; Thu, 9 Aug 2012 17:53:36 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755033Ab2HIHxe (ORCPT ); Thu, 9 Aug 2012 03:53:34 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:24881 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754371Ab2HIHxd (ORCPT ); Thu, 9 Aug 2012 03:53:33 -0400 Received: from [10.30.16.117] ([10.30.16.117]) (authenticated bits=0) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id q797rK5q027415 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 9 Aug 2012 11:53:20 +0400 (MSK) Message-ID: <50236C6F.10503@parallels.com> Date: Thu, 09 Aug 2012 11:53:19 +0400 From: Pavel Emelyanov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120209 Thunderbird/10.0.1 MIME-Version: 1.0 To: David Miller , Eric Dumazet , "Eric W. Biederman" , Linux Netdev List , Ben Hutchings Subject: [PATCH 4/5] net: Make ifindex generation per-net namespace References: <50236C20.4050108@parallels.com> In-Reply-To: <50236C20.4050108@parallels.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 Acked-by: Eric Dumazet --- include/net/net_namespace.h | 1 + net/core/dev.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) 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; } }