Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368Ab3COB1k (ORCPT ); Thu, 14 Mar 2013 21:27:40 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:47983 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751420Ab3COB1j convert rfc822-to-8bit (ORCPT ); Thu, 14 Mar 2013 21:27:39 -0400 X-IronPort-AV: E=Sophos;i="4.84,849,1355068800"; d="scan'208";a="6874996" Subject: Re: [PATCH 2/2] task_work: check callback if it's NULL From: li guang To: Li Zefan Cc: Oleg Nesterov , viro@zeniv.linux.org.uk, edumazet@google.com, linux-kernel@vger.kernel.org In-Reply-To: <514272D3.7040901@huawei.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> <1363306834.21129.121.camel@liguang.fnst.cn.fujitsu.com> <514272D3.7040901@huawei.com> Date: Fri, 15 Mar 2013 09:26:08 +0800 Message-ID: <1363310769.21129.132.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 09:26:19, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/15 09:26:19, Serialize complete at 2013/03/15 09:26:19 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: 1447 Lines: 48 在 2013-03-15五的 09:01 +0800，Li Zefan写道： > 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... > Oh, that's a little harsh to a normal programmer like me :-) for it seems you are asking me to be coding without any bug. are you? or it is the theory of kernel coding? -- 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/