On 03-02-16, 19:32, Viresh Kumar wrote:
We used to drop policy->rwsem just before calling __cpufreq_governor() in some cases earlier and so it was possible that __cpufreq_governor() runs concurrently via separate threads.
In order to guarantee valid state transitions for governors, 'governor_enabled' was required to be protected using some locking and we created cpufreq_governor_lock for that.
But now, __cpufreq_governor() is always called from within policy->rwsem held and so 'governor_enabled' is protected against races even without cpufreq_governor_lock.
Get rid of the extra lock now.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
drivers/cpufreq/cpufreq.c | 7 ------- 1 file changed, 7 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 4fc3889ca7c9..7bc8a5ed97e5 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -102,7 +102,6 @@ static LIST_HEAD(cpufreq_governor_list); static struct cpufreq_driver *cpufreq_driver; static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data); static DEFINE_RWLOCK(cpufreq_driver_lock); -DEFINE_MUTEX(cpufreq_governor_lock); /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended; @@ -1963,11 +1962,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
- mutex_lock(&cpufreq_governor_lock); if ((policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
mutex_unlock(&cpufreq_governor_lock);@@ -1976,8 +1973,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, else if (event == CPUFREQ_GOV_START) policy->governor_enabled = true;
- mutex_unlock(&cpufreq_governor_lock);
- ret = policy->governor->governor(policy, event);
if (!ret) { @@ -1987,12 +1982,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->governor->initialized--; } else { /* Restore original values */
mutex_lock(&cpufreq_governor_lock);mutex_unlock(&cpufreq_governor_lock);if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
+ minor cleanup:
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h index ed328a39c4ac..7bed63e14e7d 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -214,7 +214,6 @@ static inline int delay_for_sampling_rate(unsigned int sampling_rate) return delay; }
-extern struct mutex cpufreq_governor_lock; extern const struct sysfs_ops governor_sysfs_ops;
void gov_add_timers(struct cpufreq_policy *policy, unsigned int delay);