From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756447Ab2EKLni (ORCPT ); Fri, 11 May 2012 07:43:38 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:45969 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752368Ab2EKLng (ORCPT ); Fri, 11 May 2012 07:43:36 -0400 Subject: [RFC PATCH] SUNRPC: protect service sockets lists during per-net shutdown To: bfields@fieldses.org, Trond.Myklebust@netapp.com From: Stanislav Kinsbursky Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, devel@openvz.org Date: Fri, 11 May 2012 15:41:56 +0400 Message-ID: <20120511114126.8399.2554.stgit@localhost.localdomain> In-Reply-To: <20120509143518.GB24233@fieldses.org> References: <20120509143518.GB24233@fieldses.org> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Service sv_tempsocks and sv_permsocks lists are accessible by tasks with different network namespaces, and thus per-net service destruction must be protected. These lists are protected by service sv_lock. So lets wrap list munipulations with this lock and move tranports destruction outside wrapped area to prevent deadlocks. Signed-off-by: Stanislav Kinsbursky --- net/sunrpc/svc_xprt.c | 29 +++++++++++++++++++++++++---- 1 files changed, 25 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 8195c6a..233f993 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -954,7 +954,8 @@ static void svc_clear_pools(struct svc_serv *serv, struct net *net) } } -static void svc_clear_list(struct list_head *xprt_list, struct net *net) +static void svc_clear_list(struct list_head *xprt_list, struct net *net, + struct list_head *kill_list) { struct svc_xprt *xprt; struct svc_xprt *tmp; @@ -962,7 +963,8 @@ static void svc_clear_list(struct list_head *xprt_list, struct net *net) list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) { if (xprt->xpt_net != net) continue; - svc_delete_xprt(xprt); + list_move(&xprt->xpt_list, kill_list); + set_bit(XPT_DETACHED, &xprt->xpt_flags); } list_for_each_entry(xprt, xprt_list, xpt_list) BUG_ON(xprt->xpt_net == net); @@ -970,6 +972,15 @@ static void svc_clear_list(struct list_head *xprt_list, struct net *net) void svc_close_net(struct svc_serv *serv, struct net *net) { + struct svc_xprt *xprt; + LIST_HEAD(kill_list); + + /* + * Protect the lists, since they can be by tasks with different network + * namespace contexts. + */ + spin_lock(&serv->sv_lock); + svc_close_list(&serv->sv_tempsocks, net); svc_close_list(&serv->sv_permsocks, net); @@ -979,8 +990,18 @@ void svc_close_net(struct svc_serv *serv, struct net *net) * svc_enqueue will not add new entries without taking the * sp_lock and checking XPT_BUSY. */ - svc_clear_list(&serv->sv_tempsocks, net); - svc_clear_list(&serv->sv_permsocks, net); + svc_clear_list(&serv->sv_tempsocks, net, &kill_list); + svc_clear_list(&serv->sv_permsocks, net, &kill_list); + + spin_unlock(&serv->sv_lock); + + /* + * Destroy collected transports. + * Note: tranports has been marked as XPT_DETACHED on svc_clear_list(), + * so no need to protect againt list_del() in svc_delete_xprt(). + */ + list_for_each_entry(xprt, &kill_list, xpt_list) + svc_delete_xprt(xprt); } /*