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Subject: Re: [v5] Coccinelle: semantic code search for missing put_device()
To:     Julia Lawall <julia.lawall@lip6.fr>,
        Wen Yang <wen.yang99@zte.com.cn>
Cc:     Gilles Muller <Gilles.Muller@lip6.fr>,
        Nicolas Palix <nicolas.palix@imag.fr>,
        Michal Marek <michal.lkml@markovi.net>,
        Yi Wang <wang.yi59@zte.com.cn>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Wen Yang <yellowriver2010@hotmail.com>,
        Cheng Shengyu <cheng.shengyu@zte.com.cn>,
        cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org,
        kernel-janitors@vger.kernel.org
References: <1550217319-40418-1-git-send-email-wen.yang99@zte.com.cn>
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From:   Markus Elfring <Markus.Elfring@web.de>
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Date:   Fri, 15 Feb 2019 14:15:18 +0100
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>>> +id =3D of_find_device_by_node@p1(x)
=E2=80=A6
>>> +if (id =3D=3D NULL || ...) { ... return ...; }
>>> +... when !=3D put_device(&id->dev)
>> =E2=80=A6
>>> +    when !=3D if (id) { ... put_device(&id->dev) ... }
>> =E2=80=A6
>>
>> I would interpret this SmPL code in the way that the if statement
>> for the pointer check is =E2=80=9Coptional=E2=80=9D in this line.
>> Is it an extra and redundant SmPL specification when the reference
>> release function could eventually be found just anywhere within
>> an implementation?
>
> The proposed when code is correct.

I agree that this SmPL code can work in the way it was designed.


> It is not redundant, because it checks for a particular control-flow pat=
tern.

It took another moment until I dared to express a different software
development opinion also on this implementation detail.

Does the first SmPL when specification include the case that a call
of the function =E2=80=9Cput_device=E2=80=9D can occur within a branch of =
an if statement?

Regards,
Markus