linux-kernel - Re: [PATCH v3 13/79] media: s5p: fix pm_runtime_get

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Date:   Wed, 28 Apr 2021 09:41:52 +0200
From:   Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:     Sylwester Nawrocki <s.nawrocki@...sung.com>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v3 13/79] media: s5p: fix pm_runtime_get_sync() usage
 count

Em Tue, 27 Apr 2021 12:51:45 +0200
Sylwester Nawrocki <s.nawrocki@...sung.com> escreveu:

> On 27.04.2021 12:26, Mauro Carvalho Chehab wrote:
> > The pm_runtime_get_sync() internally increments the
> > dev->power.usage_count without decrementing it, even on errors.
> > Replace it by the new pm_runtime_resume_and_get(), introduced by:
> > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> > in order to properly decrement the usage counter and avoid memory
> > leaks.
> > 
> > While here, check if the PM runtime error was caught at
> > s5p_cec_adap_enable().
> > 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> > ---
> >  drivers/media/cec/platform/s5p/s5p_cec.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/cec/platform/s5p/s5p_cec.c b/drivers/media/cec/platform/s5p/s5p_cec.c
> > index 2a3e7ffefe0a..2250c1cbc64e 100644
> > --- a/drivers/media/cec/platform/s5p/s5p_cec.c
> > +++ b/drivers/media/cec/platform/s5p/s5p_cec.c
> > @@ -35,10 +35,13 @@ MODULE_PARM_DESC(debug, "debug level (0-2)");
> >  
> >  static int s5p_cec_adap_enable(struct cec_adapter *adap, bool enable)
> >  {
> > +	int ret;
> >  	struct s5p_cec_dev *cec = cec_get_drvdata(adap);
> >  
> >  	if (enable) {
> > -		pm_runtime_get_sync(cec->dev);
> > +		ret = pm_runtime_resume_and_get(cec->dev);
> > +		if (ret < 0)
> > +			return ret;
> >  
> >  		s5p_cec_reset(cec);  
> 
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
> 
> Not related to this patch, it seems there is bug in the second
> 'if (enable)' branch, where pm_runtime_disable() is used
> instead of pm_runtime_put(_sync)().

Yeah. I'll add an additional patch before this series in order to
fix the bug. Thanks!

Regards,
Mauro



Thanks,
Mauro