Re: [RFC][PATCH] cpufreq: Do not hold driver module references foradditional policy CPUs

From: Srivatsa S. Bhat
Date: Thu Aug 01 2013 - 15:05:14 EST


On 08/02/2013 12:31 AM, Rafael J. Wysocki wrote:
> On Thursday, August 01, 2013 11:36:49 PM Srivatsa S. Bhat wrote:
>> Its the cpufreq_cpu_get() hidden away in cpufreq_add_dev_symlink(). With
>> that taken care of, everything should be OK. Then we can change the
>> synchronization part to avoid using refcounts.
>
> So I actually don't see why cpufreq_add_dev_symlink() needs to call
> cpufreq_cpu_get() at all, since the policy refcount is already 1 at the
> point it is called and the bumping up of the driver module refcount is
> pointless.
>

Hmm, yes, it seems so.

> However, if I change that I also need to change the piece of code that
> calls the complementary cpufreq_cpu_put() and I kind of cannot find it.
>

... I guess that's because you are looking at the code with your patch
applied (and your patch removed that _put()) ;-)

Its this part in __cpufreq_remove_dev():

1303 } else {
1304
1305 if (!frozen) {
1306 pr_debug("%s: removing link, cpu: %d\n", __func__, cpu);
1307 cpufreq_cpu_put(data);
1308 }
1309


Regards,
Srivatsa S. Bhat

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