linux-kernel - Re: [PATCH v3] PM: Fix symbol export for _SIMPLE_ variants of _PM

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Date:   Wed, 20 Sep 2023 15:07:42 +0300
From:   Raag Jadav <raag.jadav@...el.com>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     rafael@...nel.org, len.brown@...el.com, pavel@....cz,
        Jonathan.Cameron@...wei.com, andriy.shevchenko@...ux.intel.com,
        rf@...nsource.cirrus.com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        mallikarjunappa.sangannavar@...el.com, bala.senthil@...el.com
Subject: Re: [PATCH v3] PM: Fix symbol export for _SIMPLE_ variants of
 _PM_OPS()

On Wed, Sep 20, 2023 at 12:00:05PM +0200, Paul Cercueil wrote:
> Le mercredi 20 septembre 2023 à 12:33 +0300, Raag Jadav a écrit :
> > On Wed, Sep 20, 2023 at 10:53:23AM +0200, Paul Cercueil wrote:
> > > Le mercredi 20 septembre 2023 à 14:11 +0530, Raag Jadav a écrit :
> > > > Currently EXPORT_*_SIMPLE_DEV_PM_OPS() use EXPORT_*_DEV_PM_OPS()
> > > > set
> > > > of macros to export dev_pm_ops symbol, which export the symbol in
> > > > case
> > > > CONFIG_PM=y but don't take CONFIG_PM_SLEEP into consideration.
> > > > 
> > > > Since _SIMPLE_ variants of _PM_OPS() do not include runtime PM
> > > > handles
> > > > and are only used in case CONFIG_PM_SLEEP=y, we should not be
> > > > exporting
> > > > their dev_pm_ops symbol in case CONFIG_PM_SLEEP=n.
> > > > 
> > > > This can be fixed by having two distinct set of export macros for
> > > > both
> > > > _RUNTIME_ and _SIMPLE_ variants of _PM_OPS(), such that the
> > > > export of
> > > > dev_pm_ops symbol used in each variant depends on CONFIG_PM and
> > > > CONFIG_PM_SLEEP respectively.
> > > > 
> > > > Introduce _DEV_SLEEP_PM_OPS() set of export macros for _SIMPLE_
> > > > variants
> > > > of _PM_OPS(), which export dev_pm_ops symbol only in case
> > > > CONFIG_PM_SLEEP=y
> > > > and discard it otherwise.
> > > > 
> > > > Fixes: 34e1ed189fab ("PM: Improve EXPORT_*_DEV_PM_OPS macros")
> > > > Signed-off-by: Raag Jadav <raag.jadav@...el.com>
> > > > ---
> > > > PS: This is a standalone fix and works without updating any
> > > > drivers.
> > > 
> > > I had to double-check that, to make sure that none of the drivers
> > > using
> > > these macros also use pm_ptr() instead of pm_sleep_ptr() to access
> > > the
> > > exported dev_pm_ops.
> > > 
> > > I did not check extensively but everything seems to use
> > > pm_sleep_ptr(),
> > > so it looks safe enough.
> > 
> > I have tested it against -rc2 without any problems.
> 
> You'd need to test an "allyesconfig" with CONFIG_PM=y, and
> CONFIG_PM_SLEEP disabled. Is that what you tested?

Yes, and also validated *.symvers if dev_pm_ops symbol is really discarded.

Seems to work as expected.

Raag