linux-kernel - Re: [PATCH] mmc: sdhci-of-arasan: Remove uninitialized ret variables

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Message-ID: <20200416202415.GA30964@ubuntu-s3-xlarge-x86>
Date:   Thu, 16 Apr 2020 13:24:15 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Michal Simek <michal.simek@...inx.com>,
        Manish Narani <manish.narani@...inx.com>,
        linux-mmc@...r.kernel.org,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        "kernelci . org bot" <bot@...nelci.org>
Subject: Re: [PATCH] mmc: sdhci-of-arasan: Remove uninitialized ret variables

On Thu, Apr 16, 2020 at 01:16:27PM -0700, Nick Desaulniers wrote:
> On Thu, Apr 16, 2020 at 11:24 AM Nathan Chancellor
> <natechancellor@...il.com> wrote:
> >
> > Clang warns:
> >
> > drivers/mmc/host/sdhci-of-arasan.c:784:9: warning: variable 'ret' is
> > uninitialized when used here [-Wuninitialized]
> >         return ret;
> >                ^~~
> > drivers/mmc/host/sdhci-of-arasan.c:738:9: note: initialize the variable
> > 'ret' to silence this warning
> >         int ret;
> >                ^
> >                 = 0
> > drivers/mmc/host/sdhci-of-arasan.c:860:9: warning: variable 'ret' is
> > uninitialized when used here [-Wuninitialized]
> >         return ret;
> >                ^~~
> > drivers/mmc/host/sdhci-of-arasan.c:810:9: note: initialize the variable
> > 'ret' to silence this warning
> >         int ret;
> >                ^
> >                 = 0
> > 2 warnings generated.
> >
> > This looks like a copy paste error. Neither function has handling that
> > needs ret so just remove it and return 0 directly.
> 
> Forgive me for not taking the time to look into this more carefully,
> but just a thought:
> 
> Having functions always return a single integer literal as opposed to
> having a `void` return type in their function signature is a code
> smell.  Did you consider the call sites of these functions to see if
> they do anything with the return value?  I understand it may not be
> worthwhile/possible if these functions fulfil an interface that
> requires the int return type function signature.  (It's also probably

Which is the case. These functions are passed to 'struct clk_ops', which
defines the set_phase member as

int     (*set_phase)(struct clk_hw *hw, int degrees);

so we cannot just change the return to void since there are other
set_phase functions that do set a return value other than zero.

> faster for me to just look rather than type this all out, but I saw no
> mention of this consideration in the commit message or patch, so
> wanted to check that it had been performed).

Yeah, I should have probably mentioned that. I can do so if the
maintainers feel it worthwhile.

Cheers,
Nathan