Merge "cpufreq: interactive: fix race on governor start/stop"
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index c70ebf5..7d1952c 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -34,7 +34,7 @@
#define CREATE_TRACE_POINTS
#include <trace/events/cpufreq_interactive.h>
-static atomic_t active_count = ATOMIC_INIT(0);
+static int active_count;
struct cpufreq_interactive_cpuinfo {
struct timer_list cpu_timer;
@@ -60,6 +60,7 @@
static struct task_struct *speedchange_task;
static cpumask_t speedchange_cpumask;
static spinlock_t speedchange_cpumask_lock;
+static struct mutex gov_lock;
/* Hi speed to bump to from lo speed when load burst (default max) */
static unsigned int hispeed_freq;
@@ -913,6 +914,8 @@
if (!cpu_online(policy->cpu))
return -EINVAL;
+ mutex_lock(&gov_lock);
+
freq_table =
cpufreq_frequency_get_table(policy->cpu);
if (!hispeed_freq)
@@ -947,20 +950,26 @@
* Do not register the idle hook and create sysfs
* entries if we have already done so.
*/
- if (atomic_inc_return(&active_count) > 1)
+ if (++active_count > 1) {
+ mutex_unlock(&gov_lock);
return 0;
+ }
rc = sysfs_create_group(cpufreq_global_kobject,
&interactive_attr_group);
- if (rc)
+ if (rc) {
+ mutex_unlock(&gov_lock);
return rc;
+ }
idle_notifier_register(&cpufreq_interactive_idle_nb);
cpufreq_register_notifier(
&cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+ mutex_unlock(&gov_lock);
break;
case CPUFREQ_GOV_STOP:
+ mutex_lock(&gov_lock);
for_each_cpu(j, policy->cpus) {
pcpu = &per_cpu(cpuinfo, j);
down_write(&pcpu->enable_sem);
@@ -970,14 +979,17 @@
up_write(&pcpu->enable_sem);
}
- if (atomic_dec_return(&active_count) > 0)
+ if (--active_count > 0) {
+ mutex_unlock(&gov_lock);
return 0;
+ }
cpufreq_unregister_notifier(
&cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
idle_notifier_unregister(&cpufreq_interactive_idle_nb);
sysfs_remove_group(cpufreq_global_kobject,
&interactive_attr_group);
+ mutex_unlock(&gov_lock);
break;
@@ -1017,6 +1029,7 @@
spin_lock_init(&target_loads_lock);
spin_lock_init(&speedchange_cpumask_lock);
+ mutex_init(&gov_lock);
speedchange_task =
kthread_create(cpufreq_interactive_speedchange_task, NULL,
"cfinteractive");