* [Question] Why is there a restriction on the policy->rwsem & CPUFREQ_GOV_POLICY_EXIT ?
@ 2014-07-23 20:45 Prarit Bhargava
2014-07-24 5:52 ` Viresh Kumar
0 siblings, 1 reply; 2+ messages in thread
From: Prarit Bhargava @ 2014-07-23 20:45 UTC (permalink / raw)
To: linux-pm; +Cc: rjw, viresh.kumar, Prarit Bhargava
I'm debugging a race/locking issue in the store_scaling_governor path and
came across the following restriction on using a semaphore in the
cpufreq_policy struct defined in include/linux/cpufreq.h :
* Additional rules:
* - Lock should not be held across
* __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
struct rw_semaphore rwsem;
I'm not completely familiar with this code and am wondering why the
restriction is in place? Is there a worry about the module_put() in
__cpufreq_governor()?
Thanks,
P.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [Question] Why is there a restriction on the policy->rwsem & CPUFREQ_GOV_POLICY_EXIT ?
2014-07-23 20:45 [Question] Why is there a restriction on the policy->rwsem & CPUFREQ_GOV_POLICY_EXIT ? Prarit Bhargava
@ 2014-07-24 5:52 ` Viresh Kumar
0 siblings, 0 replies; 2+ messages in thread
From: Viresh Kumar @ 2014-07-24 5:52 UTC (permalink / raw)
To: Prarit Bhargava; +Cc: linux-pm@vger.kernel.org, Rafael J. Wysocki
On 24 July 2014 02:15, Prarit Bhargava <prarit@redhat.com> wrote:
> I'm debugging a race/locking issue in the store_scaling_governor path and
> came across the following restriction on using a semaphore in the
> cpufreq_policy struct defined in include/linux/cpufreq.h :
>
> * Additional rules:
> * - Lock should not be held across
> * __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
>
> struct rw_semaphore rwsem;
>
> I'm not completely familiar with this code and am wondering why the
> restriction is in place? Is there a worry about the module_put() in
> __cpufreq_governor()?
955ef48 cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2014-07-24 5:52 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-07-23 20:45 [Question] Why is there a restriction on the policy->rwsem & CPUFREQ_GOV_POLICY_EXIT ? Prarit Bhargava
2014-07-24 5:52 ` Viresh Kumar
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox