linux-kernel - Re: [RFC PATCH 07/19] cpufreq: assert locking when accessing cpufreq_governor

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Date:	Tue, 12 Jan 2016 15:33:24 +0000
From:	Juri Lelli <juri.lelli@....com>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	peterz@...radead.org, rjw@...ysocki.net, mturquette@...libre.com,
	steve.muckle@...aro.org, vincent.guittot@...aro.org,
	morten.rasmussen@....com, dietmar.eggemann@....com
Subject: Re: [RFC PATCH 07/19] cpufreq: assert locking when accessing
 cpufreq_governor_list

Hi,

On 12/01/16 15:31, Viresh Kumar wrote:
> On 11-01-16, 17:35, Juri Lelli wrote:
> > @@ -2025,6 +2027,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
> >  	err = -EBUSY;
> >  	if (!find_governor(governor->name)) {
> >  		err = 0;
> > +		lockdep_assert_held(&cpufreq_governor_mutex);
> >  		list_add(&governor->governor_list, &cpufreq_governor_list);
> >  	}
> 
> Why here? This is how the routine looks like:
> 

I guess I was simply over-paranoid. We can drop this assertion.

Thanks,

- Juri

> int cpufreq_register_governor(struct cpufreq_governor *governor)
> {
> 	int err;
> 
> 	if (!governor)
> 		return -EINVAL;
> 
> 	if (cpufreq_disabled())
> 		return -ENODEV;
> 
> 	mutex_lock(&cpufreq_governor_mutex);
> 
> 	governor->initialized = 0;
> 	err = -EBUSY;
> 	if (!find_governor(governor->name)) {
> 		err = 0;
> 		list_add(&governor->governor_list, &cpufreq_governor_list);
> 	}
> 
> 	mutex_unlock(&cpufreq_governor_mutex);
> 	return err;
> }
> 
> 
> -- 
> viresh
>