linux-kernel - Re: [PATCH v4] coccinelle: semantic patch for missing put

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Message-ID: <alpine.DEB.2.21.1902150754380.2896@hadrien>
Date:   Fri, 15 Feb 2019 07:55:14 +0100 (CET)
From:   Julia Lawall <julia.lawall@...6.fr>
To:     wen.yang99@....com.cn
cc:     julia.lawall@...6.fr, markus.elfring@....de, Gilles.Muller@...6.fr,
        nicolas.palix@...g.fr, michal.lkml@...kovi.net,
        wang.yi59@....com.cn, yamada.masahiro@...ionext.com,
        yellowriver2010@...mail.com, cheng.shengyu@....com.cn,
        cocci@...teme.lip6.fr, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v4] coccinelle: semantic patch for missing put_device()



On Fri, 15 Feb 2019, wen.yang99@....com.cn wrote:

> Hi Julia, thank you very much.
>
> > > >> In a function, for variables returned by calling of_find_device_by_node(),
> > > > Do variables really get returned?
> > > > The provided pointer should usually be stored somewhere.
> > >
> > > Thank you very much, we will consider this situation and submit a next version to fix it.
> >
> > I don't know what Markus is talking about here, so I'm not sure that a
> > change is needed.
>
> I think Markus means that we need to deal with two situations:
> 1,  The return value of of_find_device_by_node () is assigned to a variable, such as:
> pdev = of_find_device_by_node(np);
> 2,  The return value of of_find_device_by_node() is assigned to a variable in a structure, such as:
> dev->pdev = of_find_device_by_node(args.np);
>
> So I plan to modify the following to capture both cases:
> -local idexpression id;
> +expression id;

I'm not sure that this is a good idea.  There is likely no need for a put
in the latter case.

julia

> ...
> id = of_find_device_by_node@p1(x)
>
> > > >> + "ERROR: missing put_device;"
> > > >Will change confidence considerations result in another fine-tuning for this message?
> > >
> > > Thank you, we will change "ERROR" to "WARNING".
> >
> > I think ERROR is fine. If it is a real positive than it is a real
> > problem. Warning is for things that look ugly, but don't have any impact
> > on the execution.
>
> OK, I will keep it.
> Thanks.
>
> Regards,
> Wen