| Message ID | 1452533760-13787-18-git-send-email-juri.lelli@arm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
On 11-01-16, 17:35, Juri Lelli wrote: > After cpufreq_driver_lock() is acquired in cpufreq_cpu_get() we are sure > we can't race with cpufreq_policy_free() (which is in the path that ends > up removing cpufreq_driver). We can thus safely remove check for > cpufreq_driver being present (which is a leftover from commit > 6eed9404ab3c ("cpufreq: Use rwsem for protecting critical sections")). > > 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 | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 797bfae..6c9bef7 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -282,15 +282,15 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) > if (WARN_ON(cpu >= nr_cpu_ids)) > return NULL; > > - /* get the cpufreq driver */ > read_lock_irqsave(&cpufreq_driver_lock, flags); > > - if (cpufreq_driver) { > - /* get the CPU */ > - policy = cpufreq_cpu_get_raw(cpu); > - if (policy) > - kobject_get(&policy->kobj); > - } > + /* > + * If we get a policy, cpufreq_policy_free() didn't > + * yet run. > + */ > + policy = cpufreq_cpu_get_raw(cpu); > + if (policy) > + kobject_get(&policy->kobj); > > read_unlock_irqrestore(&cpufreq_driver_lock, flags); Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 797bfae..6c9bef7 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -282,15 +282,15 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) if (WARN_ON(cpu >= nr_cpu_ids)) return NULL; - /* get the cpufreq driver */ read_lock_irqsave(&cpufreq_driver_lock, flags); - if (cpufreq_driver) { - /* get the CPU */ - policy = cpufreq_cpu_get_raw(cpu); - if (policy) - kobject_get(&policy->kobj); - } + /* + * If we get a policy, cpufreq_policy_free() didn't + * yet run. + */ + policy = cpufreq_cpu_get_raw(cpu); + if (policy) + kobject_get(&policy->kobj); read_unlock_irqrestore(&cpufreq_driver_lock, flags);
After cpufreq_driver_lock() is acquired in cpufreq_cpu_get() we are sure we can't race with cpufreq_policy_free() (which is in the path that ends up removing cpufreq_driver). We can thus safely remove check for cpufreq_driver being present (which is a leftover from commit 6eed9404ab3c ("cpufreq: Use rwsem for protecting critical sections")). 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 | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)