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[V2,12/14] cpufreq: stats: replace spinlock with mutex

Message ID 7b128a0d00c54b6354ab217e905fbee0e3436e84.1420177186.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar Jan. 2, 2015, 5:46 a.m. UTC 
Later commit will allocate memory from within the spinlock as that would be part
of critical region. kzalloc() might sleep and we can't sleep from inside
spinlocks critical region, so convert the spinlock into a mutex.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/cpufreq_stats.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)
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Patch

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 7701532b32c8..de55ca86b6f1 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -12,10 +12,11 @@ 
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/cputime.h>
 
-static spinlock_t cpufreq_stats_lock;
+static DEFINE_MUTEX(cpufreq_stats_lock);
 
 struct cpufreq_stats {
 	unsigned int total_trans;
@@ -39,12 +40,12 @@  static int cpufreq_stats_update(struct cpufreq_stats *stat)
 {
 	unsigned long long cur_time = get_jiffies_64();
 
-	spin_lock(&cpufreq_stats_lock);
+	mutex_lock(&cpufreq_stats_lock);
 	if (stat->time_in_state)
 		stat->time_in_state[stat->last_index] +=
 			cur_time - stat->last_time;
 	stat->last_time = cur_time;
-	spin_unlock(&cpufreq_stats_lock);
+	mutex_unlock(&cpufreq_stats_lock);
 	return 0;
 }
 
@@ -218,10 +219,10 @@  static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
 			stat->freq_table[i++] = pos->frequency;
 	stat->state_num = i;
 
-	spin_lock(&cpufreq_stats_lock);
+	mutex_lock(&cpufreq_stats_lock);
 	stat->last_time = get_jiffies_64();
 	stat->last_index = freq_table_get_index(stat, policy->cur);
-	spin_unlock(&cpufreq_stats_lock);
+	mutex_unlock(&cpufreq_stats_lock);
 
 	policy->stats_data = stat;
 	ret = sysfs_create_group(&policy->kobj, &stats_attr_group);
@@ -298,13 +299,13 @@  static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 
 	cpufreq_stats_update(stat);
 
-	spin_lock(&cpufreq_stats_lock);
+	mutex_lock(&cpufreq_stats_lock);
 	stat->last_index = new_index;
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 	stat->trans_table[old_index * stat->max_state + new_index]++;
 #endif
 	stat->total_trans++;
-	spin_unlock(&cpufreq_stats_lock);
+	mutex_unlock(&cpufreq_stats_lock);
 	cpufreq_cpu_put(policy);
 	return 0;
 }
@@ -322,7 +323,6 @@  static int __init cpufreq_stats_init(void)
 	int ret;
 	unsigned int cpu;
 
-	spin_lock_init(&cpufreq_stats_lock);
 	ret = cpufreq_register_notifier(&notifier_policy_block,
 				CPUFREQ_POLICY_NOTIFIER);
 	if (ret)