cpufreq: stats: create sysfs entries when cpufreq_stats is a module

When cpufreq_stats is compiled in as a module, cpufreq driver would
have already been registered. And so the CPUFREQ_CREATE_POLICY
notifiers wouldn't be called for it. Hence no sysfs entries for stats. :(

This patch calls cpufreq_stats_create_table() for each online CPU from
cpufreq_stats_init() and so if policy is already created for CPUx then
we will register sysfs stats for it.

When its not compiled as module, we will return early as policy wouldn't
be found for any of the CPUs.
Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq_stats.c

@@ -180,7 +180,7 @@ static void cpufreq_stats_free_table(unsigned int cpu)
 	cpufreq_cpu_put(policy);
 }
 
-static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
+static int __cpufreq_stats_create_table(struct cpufreq_policy *policy,
 		struct cpufreq_frequency_table *table)
 {
 	unsigned int i, j, count = 0, ret = 0;
@@ -253,6 +253,26 @@ static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
 	return ret;
 }
 
+static void cpufreq_stats_create_table(unsigned int cpu)
+{
+	struct cpufreq_policy *policy;
+	struct cpufreq_frequency_table *table;
+
+	/*
+	 * "likely(!policy)" because normally cpufreq_stats will be registered
+	 * before cpufreq driver
+	 */
+	policy = cpufreq_cpu_get(cpu);
+	if (likely(!policy))
+		return;
+
+	table = cpufreq_frequency_get_table(policy->cpu);
+	if (likely(table))
+		__cpufreq_stats_create_table(policy, table);
+
+	cpufreq_cpu_put(policy);
+}
+
 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 {
 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
@@ -284,7 +304,7 @@ static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
 		return 0;
 
 	if (val == CPUFREQ_CREATE_POLICY)
-		ret = cpufreq_stats_create_table(policy, table);
+		ret = __cpufreq_stats_create_table(policy, table);
 	else if (val == CPUFREQ_REMOVE_POLICY)
 		__cpufreq_stats_free_table(policy);
 
@@ -346,6 +366,9 @@ static int __init cpufreq_stats_init(void)
 	if (ret)
 		return ret;
 
+	for_each_online_cpu(cpu)
+		cpufreq_stats_create_table(cpu);
+
 	ret = cpufreq_register_notifier(&notifier_trans_block,
 				CPUFREQ_TRANSITION_NOTIFIER);
 	if (ret) {