linux-kernel - Re: [Update][PATCH] cpufreq: Do not hold driver module references for additional policy CPUs

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Message-ID: <CAKohpomGi0FzL-3FwsP=zzmbNMNUc6CN0S9Lyba+vx8m7MS4uQ@mail.gmail.com>
Date:	Fri, 2 Aug 2013 15:06:41 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux PM list <linux-pm@...r.kernel.org>,
	cpufreq@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Lists linaro-kernel <linaro-kernel@...ts.linaro.org>
Subject: Re: [Update][PATCH] cpufreq: Do not hold driver module references for
 additional policy CPUs

On 2 August 2013 12:19, Srivatsa S. Bhat
<srivatsa.bhat@...ux.vnet.ibm.com> wrote:
> On 08/02/2013 10:07 AM, Viresh Kumar wrote:
>> So, we can't rmmod the module as soon as it is inserted and so the
>> problem stays as is. :(
>>
>
> No, we get one step closer to the solution, since we fix the inconsistency
> between refcounts. Next step would be to get rid of refcounts and use
> locking like you suggested. Then we can rmmod it easily. I'm assuming
> Rafael has the same plan.

Not really. We are putting the reference at the end of add_dev() and
so refcount would be zero when we aren't running any critical sections.
And so, we can rmmod the module now and that problem is gone.

@Rafael: I will try to do generic cleanups in cpufreq in coming time
and will take care to remove .owner field completely in that. Until that
point your patches look fine:

For both of your patches:
Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
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