Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753223Ab3COBCW (ORCPT ); Thu, 14 Mar 2013 21:02:22 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:15969 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626Ab3COBCV (ORCPT ); Thu, 14 Mar 2013 21:02:21 -0400 Message-ID: <514272D3.7040901@huawei.com> Date: Fri, 15 Mar 2013 09:01:07 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130307 Thunderbird/17.0.4 MIME-Version: 1.0 To: li guang CC: Oleg Nesterov , , , Subject: Re: [PATCH 2/2] task_work: check callback if it's NULL 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> <1363306834.21129.121.camel@liguang.fnst.cn.fujitsu.com> In-Reply-To: <1363306834.21129.121.camel@liguang.fnst.cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1151 Lines: 40 On 2013/3/15 8:20, li guang wrote: > 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? > Because you're not making things safer, but your're trying to cover up bugs... -- 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/