linux-kernel - Re: [PATCH v6 3/6] kernel/reboot.c: export pm_power_off

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Date:   Wed, 13 Dec 2017 16:22:39 +0200
From:   Leonard Crestez <leonard.crestez@....com>
To:     Oleksij Rempel <o.rempel@...gutronix.de>,
        Christoph Hellwig <hch@...radead.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
CC:     Mark Rutland <mark.rutland@....com>, <devicetree@...r.kernel.org>,
        "Liam Girdwood" <lgirdwood@...il.com>,
        Shawn Guo <shawnguo@...nel.org>,
        "Michael Turquette" <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Russell King <linux@...linux.org.uk>,
        <linux-kernel@...r.kernel.org>, "Rob Herring" <robh+dt@...nel.org>,
        Mark Brown <broonie@...nel.org>, <kernel@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>,
        "Andrew Morton" <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        <linux-clk@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v6 3/6] kernel/reboot.c: export pm_power_off_prepare

On Thu, 2017-12-07 at 06:36 +0100, Oleksij Rempel wrote:
> 
> On 07.12.2017 00:11, Christoph Hellwig wrote:
> > 
> > > 
> > >  void (*pm_power_off_prepare)(void);
> > > +EXPORT_SYMBOL(pm_power_off_prepare);
> > EXPORT_SYMBOL_GPL for something this deeply internal, please.
> Ok,
> probably all other symbols should be converted in this file in to
> EXPORT_SYMBOL_GPL as well?
> 
> grep EXPORT_SYMBOL kernel/reboot.c
> EXPORT_SYMBOL(cad_pid);
> EXPORT_SYMBOL(pm_power_off_prepare);
> EXPORT_SYMBOL_GPL(emergency_restart);
> EXPORT_SYMBOL(register_reboot_notifier);
> EXPORT_SYMBOL(unregister_reboot_notifier);
> EXPORT_SYMBOL(devm_register_reboot_notifier);
> EXPORT_SYMBOL(register_restart_handler);
> EXPORT_SYMBOL(unregister_restart_handler);
> EXPORT_SYMBOL_GPL(kernel_restart);
> EXPORT_SYMBOL_GPL(kernel_halt);
> EXPORT_SYMBOL_GPL(kernel_power_off);
> EXPORT_SYMBOL_GPL(orderly_poweroff);
> EXPORT_SYMBOL_GPL(orderly_reboot);

This call looks much more deeply internal than those other functions,
it's not like reboot_notifier and restart_handler.

It seems that the only user of pm_power_off_prepare right now is the
ACPI core and your patch uses it in a regulator driver. This looks
extremely strange. Maybe this is why imx maintainers are stalling on
this patch?

It might help if the ACPI/PM maintainers ack/review this part
explicitly, and the usage in part 5:

https://patchwork.kernel.org/patch/9799615/

--
Regards,
Leonard