Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <eb51990402a466821b855092a3fa2171b5a98bcf.camel@perches.com>
Subject: Re: [PATCH v4] drivers/iio: Remove all strcpy() uses
From:   Joe Perches <joe@perches.com>
To:     Len Baker <len.baker@gmx.com>
Cc:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        David Laight <David.Laight@aculab.com>,
        Kees Cook <keescook@chromium.org>,
        linux-hardening@vger.kernel.org,
        linux-iio <linux-iio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Date:   Sun, 15 Aug 2021 09:58:02 -0700
In-Reply-To: <20210815163639.GA97260@titan>
References: <20210814135509.4500-1-len.baker@gmx.com>
         <CAHp75VdBuQTzCbz1CJciSA1+UOw0ZmJKAh8u2cbr5eDLSsRJEw@mail.gmail.com>
         <c08cfa8b6bbf07e1860d7dc93739e71ff5f4c0c4.camel@perches.com>
         <20210815163639.GA97260@titan>
Content-Type: text/plain; charset="ISO-8859-1"
User-Agent: Evolution 3.40.0-1 
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

On Sun, 2021-08-15 at 18:36 +0200, Len Baker wrote:
> Hi Joe,

Hello Len.

Don't take this advice too seriously, it's just bikeshedding
but it seems to me an unexpected use of a strcmp equivalent
in a non performance sensitive path.
 
> On Sun, Aug 15, 2021 at 08:06:45AM -0700, Joe Perches wrote:
[]
> > bikeshed:
> > 
> > I think this change is less intelligible than the original strcmp.
> 
> So, if I understand correctly you suggest to change the above line for:
> ??????????????????????????????else if (strcmp(orient, "0") == 0)

Yes.

In kernel sources it's about 2:1 in favor of '!strcmp()' over 'strcmp() == 0'

$ git grep -P '\!\s*strcmp\b' | wc -l
3457
$ git grep -P '\bstrcmp\s*\([^\)]+\)\s*==\s*0\b' | wc -l
1719

And it's your choice to use one or the other or just your V4 patch.

btw, according to godbolt:

gcc -O2 doesn't call strcmp and produces the same object code as your
byte comparisons.  clang 11 calls strcmp regardless of optimization level.