From: Stephen Boyd <sboyd@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
cw00.choi@samsung.com, Viresh Kumar <vireshk@kernel.org>,
Nishanth Menon <nm@ti.com>,
linux-pm@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
myungjoo.ham@samsung.com, inki.dae@samsung.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PM / OPP: Call notifier without holding opp_table->lock
Date: Wed, 20 Sep 2017 12:47:20 -0700 [thread overview]
Message-ID: <20170920194720.GB457@codeaurora.org> (raw)
In-Reply-To: <20170920170755.GA3001@ubuntu>
On 09/20, Viresh Kumar wrote:
> On 20-09-17, 10:00, Stephen Boyd wrote:
> > On 09/20, Viresh Kumar wrote:
>
> > > diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> > > index 4360b4efcd4c..668fd940d362 100644
> > > --- a/drivers/base/power/opp/core.c
> > > +++ b/drivers/base/power/opp/core.c
> > > @@ -1627,6 +1627,9 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
> > >
> > > opp->available = availability_req;
> > >
> > > + dev_pm_opp_get(opp);
> > > + mutex_unlock(&opp_table->lock);
> >
> > Does this prevent the OPP from changing while the lock is
> > released?
>
> No, its just ref counting and will only prevent it from getting freed.
>
> There is only one thing that can change for an OPP though after it is
> created, its availability.
Ok.
>
> > That would be the only difference from before. It's
> > possible that nobody cares about this situation though.
>
> I am not sure if its worth caring for right now :)
>
> Also the notifier chain will not start again until the previous call
> chain is finished. So we are kind of synchronized here.
>
Yep. Just me worrying out loud. You can add my
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2017-09-20 19:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20170920102206epcas1p2ae5b3a2020efa368f6c0640403695cbd@epcas1p2.samsung.com>
2017-09-20 10:22 ` OPP's mutex locking issue Chanwoo Choi
2017-09-20 15:34 ` [PATCH] PM / OPP: Call notifier without holding opp_table->lock Viresh Kumar
2017-09-20 17:00 ` Stephen Boyd
2017-09-20 17:07 ` Viresh Kumar
2017-09-20 19:47 ` Stephen Boyd [this message]
2017-09-20 20:25 ` [PATCH V2] " Viresh Kumar
2017-09-20 23:58 ` Chanwoo Choi
2017-09-21 17:44 ` [PATCH V3] " Viresh Kumar
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