forked from Minki/linux
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 <viresh.kumar@linaro.org> Tested-by: Juri Lelli <juri.lelli@arm.com> Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> [ rjw : Changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -147,8 +147,6 @@ void cpufreq_update_util(u64 time, unsigned long util, unsigned long max)
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rcu_read_unlock();
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}
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DEFINE_MUTEX(cpufreq_governor_lock);
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/* Flag to suspend/resume CPUFreq governors */
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static bool cpufreq_suspended;
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@ -2015,11 +2013,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
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pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
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mutex_lock(&cpufreq_governor_lock);
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if ((policy->governor_enabled && event == CPUFREQ_GOV_START)
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|| (!policy->governor_enabled
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&& (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) {
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mutex_unlock(&cpufreq_governor_lock);
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return -EBUSY;
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}
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@ -2028,8 +2024,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
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else if (event == CPUFREQ_GOV_START)
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policy->governor_enabled = true;
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mutex_unlock(&cpufreq_governor_lock);
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ret = policy->governor->governor(policy, event);
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if (!ret) {
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@ -2039,12 +2033,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
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policy->governor->initialized--;
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} else {
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/* Restore original values */
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mutex_lock(&cpufreq_governor_lock);
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if (event == CPUFREQ_GOV_STOP)
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policy->governor_enabled = true;
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else if (event == CPUFREQ_GOV_START)
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policy->governor_enabled = false;
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mutex_unlock(&cpufreq_governor_lock);
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}
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if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) ||
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@ -232,7 +232,6 @@ static inline int delay_for_sampling_rate(unsigned int sampling_rate)
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}
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extern struct mutex dbs_data_mutex;
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extern struct mutex cpufreq_governor_lock;
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void dbs_check_cpu(struct cpufreq_policy *policy);
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int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
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void od_register_powersave_bias_handler(unsigned int (*f)
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