Merge tag 'v3.10.37' into linux-linaro-lsk

[firefly-linux-kernel-4.4.55.git] / drivers / cpufreq / cpufreq.c

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 648554742a998aec1f2c0fdfea26adb597a8d7db..66f6cf5064ece85d201731b58757b594206b2bb7 100644 (file)
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -46,6 +46,7 @@ static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
 #endif
 static DEFINE_RWLOCK(cpufreq_driver_lock);
+static DEFINE_MUTEX(cpufreq_governor_lock);
 
 /*
  * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
@@ -1563,6 +1564,21 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 
        pr_debug("__cpufreq_governor for CPU %u, event %u\n",
                                                policy->cpu, event);
+
+       mutex_lock(&cpufreq_governor_lock);
+       if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
+           (policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
+               mutex_unlock(&cpufreq_governor_lock);
+               return -EBUSY;
+       }
+
+       if (event == CPUFREQ_GOV_STOP)
+               policy->governor_enabled = false;
+       else if (event == CPUFREQ_GOV_START)
+               policy->governor_enabled = true;
+
+       mutex_unlock(&cpufreq_governor_lock);
+
        ret = policy->governor->governor(policy, event);
 
        if (!ret) {
@@ -1570,6 +1586,14 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
                        policy->governor->initialized++;
                else if (event == CPUFREQ_GOV_POLICY_EXIT)
                        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);
        }
 
        /* we keep one module reference alive for