linux-kernel - Re: [PATCH v2] coccinelle: api: semantic patch to use pm_runtime_resume_and

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Date:   Tue, 27 Apr 2021 15:18:45 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Julia Lawall <Julia.Lawall@...ia.fr>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        kernel-janitors@...r.kernel.org,
        Gilles Muller <Gilles.Muller@...ia.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Michal Marek <michal.lkml@...kovi.net>, cocci@...teme.lip6.fr,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] coccinelle: api: semantic patch to use
 pm_runtime_resume_and_get

On Mon, Apr 26, 2021 at 08:54:04PM +0200, Julia Lawall wrote:
> pm_runtime_get_sync keeps a reference count on failure, which can lead
> to leaks.  pm_runtime_resume_and_get drops the reference count in the
> failure case.  This rule very conservatively follows the definition of
> pm_runtime_resume_and_get to address the cases where the reference
> count is unlikely to be needed in the failure case.
> 
> pm_runtime_resume_and_get was introduced in
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to
> deal with usage counter")
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@...ia.fr>

As I've said elsewhere, not sure trying to do a mass conversion of this
is a good idea. People may not be used to the interface, but it is
consistent and has its use. The recent flurry of conversions show that
those also risk introducing new bugs in code that is currently tested
and correct.

By giving the script kiddies another toy like this, the influx of broken
patches is just bound to increase.

Would also be good to CC the PM maintainer on this issue.

Johan