From patchwork Mon Aug 6 10:31:51 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Emelyanov X-Patchwork-Id: 175314 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 7BFD52C009D for ; Mon, 6 Aug 2012 20:31:59 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754659Ab2HFKb5 (ORCPT ); Mon, 6 Aug 2012 06:31:57 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:6549 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754125Ab2HFKb4 (ORCPT ); Mon, 6 Aug 2012 06:31:56 -0400 Received: from [10.30.22.37] ([10.30.22.37]) (authenticated bits=0) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id q76AVqde012047 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 6 Aug 2012 14:31:52 +0400 (MSK) Message-ID: <501F9D17.4010106@parallels.com> Date: Mon, 06 Aug 2012 14:31:51 +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 Subject: [PATCH 4/5] net: Make ifindex generation per-net namespace References: <501F9CAF.3030605@parallels.com> In-Reply-To: <501F9CAF.3030605@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. Signed-off-by: Pavel Emelyanov --- 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..c5fbebf 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -62,6 +62,7 @@ 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 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; } }