Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code

From: Ludovic BARRE <ludovic.barre@st.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
	Marek Vasut <marek.vasut@gmail.com>,
	Boris Brezillon <boris.brezillon@free-electrons.com>,
	Alexandre Torgue <alexandre.torgue@st.com>,
	Richard Weinberger <richard@nod.at>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	MTD Maling List <linux-mtd@lists.infradead.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Brian Norris <computersforpeace@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code
Date: Fri, 15 Sep 2017 09:59:05 +0200	[thread overview]
Message-ID: <fd0da95e-8e82-7293-4b6b-644f5ae1fefb@st.com> (raw)
In-Reply-To: <CAK8P3a3WoUdxpaXAiMsC3MTWSyxyUK793R+igaQjTxdO7t+a6g@mail.gmail.com>

On 09/14/2017 11:38 PM, Arnd Bergmann wrote:
> On Thu, Sep 14, 2017 at 6:55 PM, Ludovic BARRE <ludovic.barre@st.com> wrote:
>>
>>
>> On 09/14/2017 05:24 PM, Geert Uytterhoeven wrote:
>>>
>>> Hi Ludovic,
>>>
>>> On Thu, Sep 14, 2017 at 5:13 PM, Ludovic BARRE <ludovic.barre@st.com>
>>> wrote:
>>>>
>>>> On 09/14/2017 03:38 PM, Geert Uytterhoeven wrote:
>>>>
>>>> hi Arnd, Geert
>>>>
>>>> sorry, I was forgot this thread while my holidays
>>>>
>>>> Geert: what do you mean like "similar bugs in the future" in "If you
>>>> initialized ret at the beginning, you lose the ability to catch newly
>>>> introduced similar bugs in the future."
>>>
>>>
>>> If you pre-initialize ret at the top, you loose the ability of the
>>> compiler
>>> to detect at compile-time if ret is never written to later. It will just
>>> return
>>> -EINVAL at runtime.
>>>
>>> With my version, if the code is modified later and another "return ret" is
>>> added, the compiler will detect if there's a code path that forgets
>>> to assign a value to ret.
>>
>> Ok, it's clear for me.
>> I favor geert's solution.
>> Arnd what do you think ?
> 
> I usually follow the same rule that Geert explained (and quote
> https://rusty.ozlabs.org/?p=232 when I do so). In this case, there
> did not seem to be much value as the variable is not used
> afterwards, and I kept the 'single return statement' guideline.
> 
> In the end, either version seems totally fine to me here, so
> please use Geert's if you prefer that.

thank Arnd for your answer, great link :-)
we take geert's patch.

Geert: I will acked your patch.

thanks everybody
> 
>          Arnd
> 