From 99522fe6788f5bf627dce7c20ed9484c933511a3 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 11 Feb 2016 17:31:13 +0530 Subject: [PATCH] cpufreq: Remove cpufreq_governor_lock We used to drop policy->rwsem just before calling __cpufreq_governor() in some cases earlier and so it was possible that __cpufreq_governor() ran concurrently via separate threads for the same policy. In order to guarantee valid state transitions for governors, 'governor_enabled' was required to be protected using some locking and cpufreq_governor_lock was added for that. But now __cpufreq_governor() is always called under policy->rwsem, and 'governor_enabled' is protected against races even without cpufreq_governor_lock. Get rid of the extra lock now. Signed-off-by: Viresh Kumar Tested-by: Juri Lelli Tested-by: Shilpasri G Bhat [ rjw : Changelog ] Signed-off-by: Rafael J. Wysocki --- 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 692876892457..bc93272b4a12 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -147,8 +147,6 @@ 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; @@ -2015,11 +2013,9 @@ 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; } @@ -2028,8 +2024,6 @@ 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) { @@ -2039,12 +2033,10 @@ 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 8bf4775ce03c..e9ec411042c3 100644 --- a/drivers/cpufreq/cpufreq_governor.h +++ b/drivers/cpufreq/cpufreq_governor.h @@ -232,7 +232,6 @@ 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)