From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753487AbbCSL5y (ORCPT ); Thu, 19 Mar 2015 07:57:54 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:2486 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750915AbbCSL5w (ORCPT ); Thu, 19 Mar 2015 07:57:52 -0400 Message-ID: <550AB99D.5010006@huawei.com> Date: Thu, 19 Mar 2015 19:57:17 +0800 From: Xie XiuQi User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Borislav Petkov CC: , , , , , , , Subject: Re: [PATCH] trace, RAS: remove unnecessary const References: <1426755004-28434-1-git-send-email-xiexiuqi@huawei.com> <20150319103330.GC11544@pd.tnic> In-Reply-To: <20150319103330.GC11544@pd.tnic> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.177.17.191] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.550AB9B6.0140,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 63db1eb682d0dbe2fa2222461f984b47 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/3/19 18:33, Borislav Petkov wrote: > On Thu, Mar 19, 2015 at 04:50:04PM +0800, Xie XiuQi wrote: >> These parameters are passed by value. There's no need to make them const. > > I can think of a reason: > > include/trace/../../include/ras/ras_event.h: In function ‘ftrace_raw_event_mc_event’: > include/trace/../../include/ras/ras_event.h:136:35: error: assignment of read-only parameter ‘top_layer’ > __entry->top_layer = top_layer = 12; Oh, indeed. Thanks, Boris! > ^ > --- > diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h > index 79abb9c71772..e4721eac3e25 100644 > --- a/include/ras/ras_event.h > +++ b/include/ras/ras_event.h > @@ -133,7 +133,7 @@ TRACE_EVENT(mc_event, > __assign_str(label, label); > __entry->error_count = error_count; > __entry->mc_index = mc_index; > - __entry->top_layer = top_layer; > + __entry->top_layer = top_layer = 12; > __entry->middle_layer = mid_layer; > __entry->lower_layer = low_layer; > __entry->address = address; > --- > > I'm not saying it is a particularly sane reason and no one would even > *think* of changing TP parameters passed on from higher layers in the TP > itself but I've seen people do lotsa crazy things - things they normally > would never do - so if it doesn't hurt having the const here, what's the > downside of having the compiler do that sanity checking for us too? > > Steve, this is an invitation for your crazy fantasy! :-P >