linux-kernel - Re: [PATCH 06/12] PM / OPP: Add 'struct kref' to struct dev_pm

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Message-ID: <20170110042632.GC6332@vireshk-i7>
Date:   Tue, 10 Jan 2017 09:56:32 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Stephen Boyd <sboyd@...eaurora.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>
Subject: Re: [PATCH 06/12] PM / OPP: Add 'struct kref' to struct dev_pm_opp

On 09-01-17, 15:44, Stephen Boyd wrote:
> On 12/07, Viresh Kumar wrote:
> > Add kref to struct dev_pm_opp for easier accounting of the OPPs.
> > 
> > Note that the OPPs are freed under the opp_table->lock mutex only.
> 
> I'm lost. Why add another level of krefs?

Heh. The earlier krefs were for the OPP table itself, so that it gets freed once
there are no more users of it.

The kref introduced now is for individual OPPs, so that they don't disappear
while being used and gets freed once all are done.

Also note that the OPP table will get freed only after all the OPPs are freed,
plus there are no more users left, like platform code which might have set
suppoerted-hw property.

-- 
viresh