From owner-svn-src-projects@FreeBSD.ORG Wed Jan 26 22:05:40 2011 Return-Path: Delivered-To: svn-src-projects@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 76BD8106566B; Wed, 26 Jan 2011 22:05:40 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 471D78FC13; Wed, 26 Jan 2011 22:05:40 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id E623D46B03; Wed, 26 Jan 2011 17:05:39 -0500 (EST) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 11C1F8A009; Wed, 26 Jan 2011 17:05:39 -0500 (EST) From: John Baldwin To: Warner Losh Date: Wed, 26 Jan 2011 16:54:51 -0500 User-Agent: KMail/1.13.5 (FreeBSD/7.4-CBSD-20110107; KDE/4.4.5; amd64; ; ) References: <201101262034.p0QKYGkB089319@svn.freebsd.org> In-Reply-To: <201101262034.p0QKYGkB089319@svn.freebsd.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201101261654.51397.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (bigwig.baldwin.cx); Wed, 26 Jan 2011 17:05:39 -0500 (EST) X-Virus-Scanned: clamav-milter 0.96.3 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.9 required=4.2 tests=BAYES_00 autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on bigwig.baldwin.cx Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r217907 - projects/graid/head/sys/geom/raid X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Jan 2011 22:05:40 -0000 On Wednesday, January 26, 2011 3:34:16 pm Warner Losh wrote: > Author: imp > Date: Wed Jan 26 20:34:16 2011 > New Revision: 217907 > URL: http://svn.freebsd.org/changeset/base/217907 > > Log: > Set arg before timeout function pointer to avoid a 1 instruction race. > > Modified: > projects/graid/head/sys/geom/raid/tr_raid1.c > > Modified: projects/graid/head/sys/geom/raid/tr_raid1.c > ============================================================================== > --- projects/graid/head/sys/geom/raid/tr_raid1.c Wed Jan 26 20:29:28 2011 (r217906) > +++ projects/graid/head/sys/geom/raid/tr_raid1.c Wed Jan 26 20:34:16 2011 (r217907) > @@ -259,8 +259,8 @@ g_raid_tr_update_state_raid1(struct g_ra > G_RAID_EVENT_VOLUME); > if (s == G_RAID_VOLUME_S_DEGRADED) { > g_raid_tr_raid1_rebuild_start(vol->v_tr, vol); > - vol->v_timeout = g_raid_tr_raid1_idle_rebuild; > vol->v_to_arg = trs; > + vol->v_timeout = g_raid_tr_raid1_idle_rebuild; > } else { > vol->v_timeout = 0; > vol->v_to_arg = 0; Err, this can't solve anything without a memory barrier given the ability of modern CPUs on at least some architectures to reorder writes. -- John Baldwin