cpufreq: stats: pass 'stat' to cpufreq_stats_update()

It is better to pass a struct cpufreq_stats pointer to cpufreq_stats_update()
instead of a CPU number, because that's all it needs.

Even if we pass a cpu number to cpufreq_stats_update(), it reads the per-cpu
variable to get 'stats' out of it. So we are doing these operations
unnecessarily:
- First getting the cpu number to pass to cpufreq_stats_update(), stat->cpu.
- And then getting stats from the cpu, per_cpu(cpufreq_stats_table, cpu).

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
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

@@ -33,13 +33,11 @@ struct cpufreq_stats {
 
 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
 
-static int cpufreq_stats_update(unsigned int cpu)
+static int cpufreq_stats_update(struct cpufreq_stats *stat)
 {
-	struct cpufreq_stats *stat;
 	unsigned long long cur_time = get_jiffies_64();
 
 	spin_lock(&cpufreq_stats_lock);
-	stat = per_cpu(cpufreq_stats_table, cpu);
 	if (stat->time_in_state)
 		stat->time_in_state[stat->last_index] +=
 			cur_time - stat->last_time;
@@ -64,7 +62,7 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 	if (!stat)
 		return 0;
-	cpufreq_stats_update(stat->cpu);
+	cpufreq_stats_update(stat);
 	for (i = 0; i < stat->state_num; i++) {
 		len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
 			(unsigned long long)
@@ -82,7 +80,7 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 	struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
 	if (!stat)
 		return 0;
-	cpufreq_stats_update(stat->cpu);
+	cpufreq_stats_update(stat);
 	len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
 	len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
 	for (i = 0; i < stat->state_num; i++) {
@@ -307,7 +305,7 @@ static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 	if (old_index == -1 || new_index == -1)
 		return 0;
 
-	cpufreq_stats_update(freq->cpu);
+	cpufreq_stats_update(stat);
 
 	if (old_index == new_index)
 		return 0;