linux-kernel - Re: [PATCH v3] Coccinelle: semantic patch for missing put

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Message-ID: <alpine.DEB.2.21.1902132050200.2655@hadrien>
Date:   Wed, 13 Feb 2019 20:52:21 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     Markus Elfring <Markus.Elfring@....de>
cc:     Wen Yang <wen.yang99@....com.cn>,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Wen Yang <yellowriver2010@...mail.com>,
        Xue Zhihong <xue.zhihong@....com.cn>,
        Yi Wang <wang.yi59@....com.cn>, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org, Coccinelle <cocci@...teme.lip6.fr>
Subject: Re: [PATCH v3] Coccinelle: semantic patch for missing put_device()



On Wed, 13 Feb 2019, Markus Elfring wrote:

> > The of_find_device_by_node() takes a reference to the underlying device
> > structure, we should release that reference.
>
> I have got another concern for further software development considerations.
>
> How do you think about to describe here if it can be determined
> by source code analysis that the desired release should be performed
> only in the same function implementation (or not)?
>
> How much does this aspect influence the source code search confidence?
>
>
> > +    when != e1 = (T)id
> > +    when != e2 = &id->dev
> > +    when != e3 = get_device(&id->dev)
> > +    when != e4 = (T1)platform_get_drvdata(id)
>
> I have got another idea for a bit of software fine-tuning at such a place.
> I am unsure if it can become relevant to reduce the number of metavariables
> here by introducing a SmPL disjunction.
>
> +    when != ex = \( (T)id \| &id->dev \| get_device(&id->dev) \| (T1)platform_get_drvdata(id) \)

There is no need for the disjunction.  There is also no need for the
different variables.  Different variables are only needed when the when
conditions are on different ...s

julia

>
>
> Regards,
> Markus
>