linux-kernel - Re: linux-4.14-rc1/arch/powerpc/perf/hv-24x7.c:541: bad condition ?

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Message-ID: <87poankm95.fsf@concordia.ellerman.id.au>
Date:   Tue, 19 Sep 2017 20:37:10 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     David Binderman <dcb314@...mail.com>,
        "benh\@kernel.crashing.org" <benh@...nel.crashing.org>,
        "paulus\@samba.org" <paulus@...ba.org>,
        "linuxppc-dev\@lists.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: linux-4.14-rc1/arch/powerpc/perf/hv-24x7.c:541: bad condition ?

David Binderman <dcb314@...mail.com> writes:

> Hello there,
>
> linux-4.14-rc1/arch/powerpc/perf/hv-24x7.c:543]: (warning) Identical condition 's1<s2', second condition is always false
>
> Source code is
>
>     if (s1 < s2)
>         return 1;
>     if (s2 > s1)
>         return -1;
>
> Suggest code rework.

Um thanks.

It's trying to implement a sort comparison returning -1, 0, 1.

So it's pretty obviously wrong, but also harmless AFAICS, because it's
just an optimisation before doing a full comparison using memcmp().

So yeah we should fix it, but not an actual bug AFAICS.

cheers