linux-kernel - Re: [PATCH v1] PM / sleep: make pm notifier called symmetrically

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Message-ID: <4137764.SdaSPLogrJ@vostro.rjw.lan>
Date:	Wed, 08 Jun 2016 02:40:04 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Lianwei Wang <lianwei.wang@...il.com>
Cc:	"Rafael J. Wysocki" <rafael@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v1] PM / sleep: make pm notifier called symmetrically

On Monday, June 06, 2016 10:41:25 PM Lianwei Wang wrote:
> On Wed, May 18, 2016 at 11:06 PM, Lianwei Wang <lianwei.wang@...il.com> wrote:
> > On Wed, May 18, 2016 at 1:34 PM, Rafael J. Wysocki <rafael@...nel.org> wrote:
> >> On Wed, May 18, 2016 at 8:07 AM, Lianwei Wang <lianwei.wang@...il.com> wrote:
> >>> This makes pm notifier PREPARE/POST symmetrical: if PREPARE
> >>> fails, we will only undo what ever happened on PREPARE.
> >>>
> >>> It fixes the unbalanced cpu hotplug enable in cpu pm notifier.
> >>
> >> Can you please describe the problem you're trying to address in a bit
> >> more detail?
> >
> > It is described in another patch, and it is a common issue. I fixed
> > the similar issue several times, all because that the CPU_POST_SUSPEND
> > notifier callback is called without call CPU_SUSPEND_PREPARE notifier
> > callback before. Something is DO in PM_XXX_PREPARE and UNDO in
> > POST_XXX. If we don't DO it in XXX_PREPARE then we don't need to UNDO
> > it in  PM_POST_XXX.
> >
> > Here is the link for the unbalanced cpu hotplug enable case:
> > https://lkml.org/lkml/2016/5/6/61 .
> >
> > Thanks,
> > Lianwei
> 
> Did anyone from the maintainer review the patch yet?

Yes, I have reviewed it, but not yet decided whether or not I will accept it.

Thanks,
Rafael