From patchwork Thu Jun 18 11:08:23 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 28857 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@bilbo.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 9441BB7293 for ; Thu, 18 Jun 2009 21:09:23 +1000 (EST) Received: by ozlabs.org (Postfix) id 88CBADDDA2; Thu, 18 Jun 2009 21:09:23 +1000 (EST) Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 1153CDDDA1 for ; Thu, 18 Jun 2009 21:09:23 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756884AbZFRLJN (ORCPT ); Thu, 18 Jun 2009 07:09:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755923AbZFRLJN (ORCPT ); Thu, 18 Jun 2009 07:09:13 -0400 Received: from xc.sipsolutions.net ([83.246.72.84]:48324 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753298AbZFRLJM (ORCPT ); Thu, 18 Jun 2009 07:09:12 -0400 Received: by sipsolutions.net with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.69) (envelope-from ) id 1MHFUY-0003Za-Hq; Thu, 18 Jun 2009 13:09:14 +0200 Subject: [PATCH] net: make namespace iteration possible under RCU From: Johannes Berg To: Netdev Cc: "Eric W. Biederman" Date: Thu, 18 Jun 2009 13:08:23 +0200 Message-Id: <1245323303.31588.86.camel@johannes.local> Mime-Version: 1.0 X-Mailer: Evolution 2.26.2 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org All we need to take care of is using proper RCU list add/del primitives and inserting a synchronize_rcu() at one place to make sure the exit notifiers are run after everybody has stopped iterating the list. Signed-off-by: Johannes Berg --- include/net/net_namespace.h | 3 +++ net/core/net_namespace.c | 10 +++++++--- 2 files changed, 10 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- wireless-testing.orig/include/net/net_namespace.h 2009-06-18 01:36:26.000000000 +0200 +++ wireless-testing/include/net/net_namespace.h 2009-06-18 02:17:14.000000000 +0200 @@ -211,6 +211,9 @@ static inline struct net *read_pnet(stru #define for_each_net(VAR) \ list_for_each_entry(VAR, &net_namespace_list, list) +#define for_each_net_rcu(VAR) \ + list_for_each_entry_rcu(VAR, &net_namespace_list, list) + #ifdef CONFIG_NET_NS #define __net_init #define __net_exit --- wireless-testing.orig/net/core/net_namespace.c 2009-06-18 01:36:39.000000000 +0200 +++ wireless-testing/net/core/net_namespace.c 2009-06-18 02:03:06.000000000 +0200 @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -134,7 +135,7 @@ struct net *copy_net_ns(unsigned long fl err = setup_net(new_net); if (!err) { rtnl_lock(); - list_add_tail(&new_net->list, &net_namespace_list); + list_add_tail_rcu(&new_net->list, &net_namespace_list); rtnl_unlock(); } mutex_unlock(&net_mutex); @@ -163,9 +164,12 @@ static void cleanup_net(struct work_stru /* Don't let anyone else find us. */ rtnl_lock(); - list_del(&net->list); + list_del_rcu(&net->list); rtnl_unlock(); + /* if somebody is rcu-iterating the list, wait */ + synchronize_rcu(); + /* Run all of the network namespace exit methods */ list_for_each_entry_reverse(ops, &pernet_list, list) { if (ops->exit) @@ -227,7 +231,7 @@ static int __init net_ns_init(void) err = setup_net(&init_net); rtnl_lock(); - list_add_tail(&init_net.list, &net_namespace_list); + list_add_tail_rcu(&init_net.list, &net_namespace_list); rtnl_unlock(); mutex_unlock(&net_mutex);