From patchwork Fri Feb 15 19:23:03 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 2149601 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 2AC3ADF24C for ; Fri, 15 Feb 2013 19:23:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751346Ab3BOTXK (ORCPT ); Fri, 15 Feb 2013 14:23:10 -0500 Received: from fieldses.org ([174.143.236.118]:37601 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751139Ab3BOTXH (ORCPT ); Fri, 15 Feb 2013 14:23:07 -0500 Received: from bfields by fieldses.org with local (Exim 4.76) (envelope-from ) id 1U6QsC-0005PX-1M; Fri, 15 Feb 2013 14:23:04 -0500 Date: Fri, 15 Feb 2013 14:23:03 -0500 From: "J. Bruce Fields" To: Mark Lord Cc: Mark Lord , Stanislav Kinsbursky , linux-nfs@vger.kernel.org, Linux Kernel , =?utf-8?B?UGF3ZcWC?= Sikora , Tom Horsley , Jason Tibbitts Subject: [PATCH 1/2] svcrpc: make svc_age_temp_xprts enqueue under sv_lock Message-ID: <20130215192303.GD19923@fieldses.org> References: <50F63882.8000607@parallels.com> <50F72F03.5070806@teksavvy.com> <50F786AF.4070107@parallels.com> <20130117130335.GD6598@fieldses.org> <50F7FB7E.2020503@parallels.com> <50F88C14.7030903@teksavvy.com> <50F8DF7E.8080107@parallels.com> <50FC74E0.20305@teksavvy.com> <20130212205216.GE10267@fieldses.org> <511BAAAA.9040804@start.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <511BAAAA.9040804@start.ca> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org svc_age_temp_xprts expires xprts in a two-step process: first it takes the sv_lock and moves the xprts to expire off their server-wide list (sv_tempsocks or sv_permsocks) to a local list. Then it drops the sv_lock and enqueues and puts each one. I see no reason for this: svc_xprt_enqueue() will take sp_lock, but the sv_lock and sp_lock are not otherwise nested anywhere (and documentation at the top of this file claims it's correct to nest these with sp_lock inside.) Cc: stable@kernel.org Tested-by: Jason Tibbitts Signed-off-by: J. Bruce Fields --- net/sunrpc/svc_xprt.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 5a9d40c..11a33c8 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -863,7 +863,6 @@ static void svc_age_temp_xprts(unsigned long closure) struct svc_serv *serv = (struct svc_serv *)closure; struct svc_xprt *xprt; struct list_head *le, *next; - LIST_HEAD(to_be_aged); dprintk("svc_age_temp_xprts\n"); @@ -884,25 +883,15 @@ static void svc_age_temp_xprts(unsigned long closure) if (atomic_read(&xprt->xpt_ref.refcount) > 1 || test_bit(XPT_BUSY, &xprt->xpt_flags)) continue; - svc_xprt_get(xprt); - list_move(le, &to_be_aged); + list_del_init(le); set_bit(XPT_CLOSE, &xprt->xpt_flags); set_bit(XPT_DETACHED, &xprt->xpt_flags); - } - spin_unlock_bh(&serv->sv_lock); - - while (!list_empty(&to_be_aged)) { - le = to_be_aged.next; - /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */ - list_del_init(le); - xprt = list_entry(le, struct svc_xprt, xpt_list); - dprintk("queuing xprt %p for closing\n", xprt); /* a thread will dequeue and close it soon */ svc_xprt_enqueue(xprt); - svc_xprt_put(xprt); } + spin_unlock_bh(&serv->sv_lock); mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); }