Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753066Ab3COAWE (ORCPT ); Thu, 14 Mar 2013 20:22:04 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:28342 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752799Ab3COAWC convert rfc822-to-8bit (ORCPT ); Thu, 14 Mar 2013 20:22:02 -0400 X-IronPort-AV: E=Sophos;i="4.84,848,1355068800"; d="scan'208";a="6874650" Subject: Re: [PATCH 2/2] task_work: check callback if it's NULL From: li guang To: Oleg Nesterov Cc: viro@zeniv.linux.org.uk, edumazet@google.com, linux-kernel@vger.kernel.org In-Reply-To: <20130314144307.GB16136@redhat.com> References: <1363247865-3531-1-git-send-email-lig.fnst@cn.fujitsu.com> <1363247865-3531-2-git-send-email-lig.fnst@cn.fujitsu.com> <20130314144307.GB16136@redhat.com> Date: Fri, 15 Mar 2013 08:20:34 +0800 Message-ID: <1363306834.21129.121.camel@liguang.fnst.cn.fujitsu.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/15 08:20:43, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/15 08:20:44, Serialize complete at 2013/03/15 08:20:44 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1018 Lines: 35 在 2013-03-14四的 15:43 +0100，Oleg Nesterov写道： > On 03/14, liguang wrote: > > > > Signed-off-by: liguang > > --- > > kernel/task_work.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/kernel/task_work.c b/kernel/task_work.c > > index 0bf4258..f458b08 100644 > > --- a/kernel/task_work.c > > +++ b/kernel/task_work.c > > @@ -75,7 +75,8 @@ void task_work_run(void) > > > > do { > > next = work->next; > > - work->func(work); > > + if (unlikely(work->func)) > > + work->func(work); > > Why? > > Oleg. > can we believe a callback always be call-able? can it happened to be 0? e.g. wrong initialized. of course, we can complain the caller, be why don't we easily make it more safer? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/