1 files changed, 73 insertions, 27 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e10922709d13..7ea217c88c2e 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -34,11 +34,6 @@
 
 static LIST_HEAD(cpufreq_policy_list);
 
-static inline bool policy_is_inactive(struct cpufreq_policy *policy)
-{
-	return cpumask_empty(policy->cpus);
-}
-
 /* Macros to iterate over CPU policies */
 #define for_each_suitable_policy(__policy, __active)			 \
 	list_for_each_entry(__policy, &cpufreq_policy_list, policy_list) \
@@ -250,6 +245,51 @@ void cpufreq_cpu_put(struct cpufreq_policy *policy)
 }
 EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
 
+/**
+ * cpufreq_cpu_release - Unlock a policy and decrement its usage counter.
+ * @policy: cpufreq policy returned by cpufreq_cpu_acquire().
+ */
+void cpufreq_cpu_release(struct cpufreq_policy *policy)
+{
+	if (WARN_ON(!policy))
+		return;
+
+	lockdep_assert_held(&policy->rwsem);
+
+	up_write(&policy->rwsem);
+
+	cpufreq_cpu_put(policy);
+}
+
+/**
+ * cpufreq_cpu_acquire - Find policy for a CPU, mark it as busy and lock it.
+ * @cpu: CPU to find the policy for.
+ *
+ * Call cpufreq_cpu_get() to get a reference on the cpufreq policy for @cpu and
+ * if the policy returned by it is not NULL, acquire its rwsem for writing.
+ * Return the policy if it is active or release it and return NULL otherwise.
+ *
+ * The policy returned by this function has to be released with the help of
+ * cpufreq_cpu_release() in order to release its rwsem and balance its usage
+ * counter properly.
+ */
+struct cpufreq_policy *cpufreq_cpu_acquire(unsigned int cpu)
+{
+	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+
+	if (!policy)
+		return NULL;
+
+	down_write(&policy->rwsem);
+
+	if (policy_is_inactive(policy)) {
+		cpufreq_cpu_release(policy);
+		return NULL;
+	}
+
+	return policy;
+}
+
 /*********************************************************************
  *            EXTERNALLY AFFECTING FREQUENCY CHANGES                 *
  *********************************************************************/
@@ -669,9 +709,6 @@ static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
 	return ret;
 }
 
-static int cpufreq_set_policy(struct cpufreq_policy *policy,
-				struct cpufreq_policy *new_policy);
-
 /**
  * cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
  */
@@ -857,11 +894,9 @@ static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
 {
 	unsigned int limit;
 	int ret;
-	if (cpufreq_driver->bios_limit) {
-		ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
-		if (!ret)
-			return sprintf(buf, "%u\n", limit);
-	}
+	ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
+	if (!ret)
+		return sprintf(buf, "%u\n", limit);
 	return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
 }
 
@@ -1098,6 +1133,7 @@ static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu)
 				   cpufreq_global_kobject, "policy%u", cpu);
 	if (ret) {
 		pr_err("%s: failed to init policy->kobj: %d\n", __func__, ret);
+		kobject_put(&policy->kobj);
 		goto err_free_real_cpus;
 	}
 
@@ -1550,7 +1586,7 @@ static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
 {
 	unsigned int ret_freq = 0;
 
-	if (unlikely(policy_is_inactive(policy)) || !cpufreq_driver->get)
+	if (unlikely(policy_is_inactive(policy)))
 		return ret_freq;
 
 	ret_freq = cpufreq_driver->get(policy->cpu);
@@ -1588,7 +1624,8 @@ unsigned int cpufreq_get(unsigned int cpu)
 
 	if (policy) {
 		down_read(&policy->rwsem);
-		ret_freq = __cpufreq_get(policy);
+		if (cpufreq_driver->get)
+			ret_freq = __cpufreq_get(policy);
 		up_read(&policy->rwsem);
 
 		cpufreq_cpu_put(policy);
@@ -2229,8 +2266,8 @@ EXPORT_SYMBOL(cpufreq_get_policy);
  *
  * The cpuinfo part of @policy is not updated by this function.
  */
-static int cpufreq_set_policy(struct cpufreq_policy *policy,
-			      struct cpufreq_policy *new_policy)
+int cpufreq_set_policy(struct cpufreq_policy *policy,
+		       struct cpufreq_policy *new_policy)
 {
 	struct cpufreq_governor *old_gov;
 	int ret;
@@ -2337,17 +2374,12 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
  */
 void cpufreq_update_policy(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
 	struct cpufreq_policy new_policy;
 
 	if (!policy)
 		return;
 
-	down_write(&policy->rwsem);
-
-	if (policy_is_inactive(policy))
-		goto unlock;
-
 	/*
 	 * BIOS might change freq behind our back
 	 * -> ask driver for current freq and notify governors about a change
@@ -2364,12 +2396,26 @@ void cpufreq_update_policy(unsigned int cpu)
 	cpufreq_set_policy(policy, &new_policy);
 
 unlock:
-	up_write(&policy->rwsem);
-
-	cpufreq_cpu_put(policy);
+	cpufreq_cpu_release(policy);
 }
 EXPORT_SYMBOL(cpufreq_update_policy);
 
+/**
+ * cpufreq_update_limits - Update policy limits for a given CPU.
+ * @cpu: CPU to update the policy limits for.
+ *
+ * Invoke the driver's ->update_limits callback if present or call
+ * cpufreq_update_policy() for @cpu.
+ */
+void cpufreq_update_limits(unsigned int cpu)
+{
+	if (cpufreq_driver->update_limits)
+		cpufreq_driver->update_limits(cpu);
+	else
+		cpufreq_update_policy(cpu);
+}
+EXPORT_SYMBOL_GPL(cpufreq_update_limits);
+
 /*********************************************************************
  *               BOOST						     *
  *********************************************************************/
@@ -2426,7 +2472,7 @@ int cpufreq_boost_trigger_state(int state)
 
 static bool cpufreq_boost_supported(void)
 {
-	return likely(cpufreq_driver) && cpufreq_driver->set_boost;
+	return cpufreq_driver->set_boost;
 }
 
 static int create_boost_sysfs_file(void)