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 | 8 -------- drivers/cpufreq/cpufreq_governor.h | 1 - 2 files changed, 9 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 51fb47cd38a0..745da90d7b38 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -146,8 +146,6 @@ void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) rcu_read_unlock(); }
-DEFINE_MUTEX(cpufreq_governor_lock); - /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended;
@@ -2014,11 +2012,9 @@ 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); return -EBUSY; }
@@ -2027,8 +2023,6 @@ 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) { @@ -2038,12 +2032,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->governor->initialized--; } else { /* Restore original values */ - mutex_lock(&cpufreq_governor_lock); if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = true; else if (event == CPUFREQ_GOV_START) policy->governor_enabled = false; - mutex_unlock(&cpufreq_governor_lock); }
if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h index f164437f235e..886578b5a4fd 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -228,7 +228,6 @@ static inline int delay_for_sampling_rate(unsigned int sampling_rate) }
extern struct mutex dbs_data_mutex; -extern struct mutex cpufreq_governor_lock; void dbs_check_cpu(struct cpufreq_policy *policy); int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event); void od_register_powersave_bias_handler(unsigned int (*f)