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References: <20220720102956.1141634-1-zengjx95@gmail.com> <YtfoCAKfV8PXQz5h@worktop.programming.kicks-ass.net>
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From:   jingxiang zeng <zengjx95@gmail.com>
Date:   Wed, 20 Jul 2022 20:25:37 +0800
Message-ID: <CAPp=jc8wdLd7rZGuun3FH6k2nDMsfMLHF94M=ZOjbaEFvS6WRQ@mail.gmail.com>
Subject: Re: [PATCH] kernel/sched/cputime: Fix unused value in cputime_adjust()
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     mingo@redhat.com, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
        bristot@redhat.com, vschneid@redhat.com,
        linux-kernel@vger.kernel.org,
        Zeng Jingxiang <linuszeng@tencent.com>
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Peter Zijlstra <peterz@infradead.org> =E4=BA=8E2022=E5=B9=B47=E6=9C=8820=E6=
=97=A5=E5=91=A8=E4=B8=89 19:33=E5=86=99=E9=81=93=EF=BC=9A
>
> On Wed, Jul 20, 2022 at 06:29:56PM +0800, zengjx95@gmail.com wrote:
> > From: Zeng Jingxiang <linuszeng@tencent.com>
> >
> > Coverity warns uf an unused value:
> >
> > assigned_value: Assign the value of the variable rtime to utime here,
> > but that stored value is overwritten before it can be used.
> > 568   if (stime =3D=3D 0) {
> > 569           utime =3D rtime;
> > 570           goto update;
> > 571   }
> >
> > value_overwrite: Overwriting previous write to utime with
> > the value of expression rtime - stime.
> > 592   utime =3D rtime - stime;
>
> Coverity is being daft, the compiler has a dead-store-elimination pass.
>
> This way the code is more consistent / easier to ready.


Thank you for your suggestion, I will try it.