Messages in this thread | | | Date | Tue, 12 Jan 2016 15:04:52 +0530 | From | Viresh Kumar <> | Subject | Re: [RFC PATCH 05/19] cpufreq: assert locking when accessing cpufreq_policy_list |
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On 11-01-16, 17:35, Juri Lelli wrote: > cpufreq_policy_list is guarded by cpufreq_driver_lock. Add appropriate > locking assertions to check that we always access the list while holding > the associated lock. > > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Signed-off-by: Juri Lelli <juri.lelli@arm.com> > --- > drivers/cpufreq/cpufreq.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 00a00cd..63d6efb 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -65,6 +65,7 @@ static bool suitable_policy(struct cpufreq_policy *policy, bool active) > static struct cpufreq_policy *next_policy(struct cpufreq_policy *policy, > bool active) > { > + lockdep_assert_held(&cpufreq_driver_lock); > do { > policy = list_next_entry(policy, policy_list); > > @@ -80,6 +81,7 @@ static struct cpufreq_policy *first_policy(bool active) > { > struct cpufreq_policy *policy; > > + lockdep_assert_held(&cpufreq_driver_lock);
Because both first_policy() and next_policy() are parts of for_each_suitable_policy() macro, checking this in first_policy() is sufficient. next_policy() isn't designed to be used by any other code.
> /* No policies in the list */ > if (list_empty(&cpufreq_policy_list)) > return NULL; > @@ -2430,6 +2432,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) > if (ret) > goto err_boost_unreg; > > + lockdep_assert_held(&cpufreq_driver_lock);
Why do you need a cpufreq_driver_lock here? And the above change should generate a lockdep here as the lock isn't taken right now.
> if (!(cpufreq_driver->flags & CPUFREQ_STICKY) && > list_empty(&cpufreq_policy_list)) { > /* if all ->init() calls failed, unregister */ > -- > 2.2.2
-- viresh
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