cpufreq: interactive: Unify Governor Lock Strategy

Change our locking strategy to be the same as the conservative
and ondemand governor for GOV_START and GOV_STOP to allow
for correct handling of multiple CPUs

Bug 1049258

Change-Id: I15ab620e2f9d47b00ec8186c224eb719b9735aa7
Signed-off-by: Matt Wagner <mwagner@nvidia.com>
Reviewed-on: http://git-master/r/133360
Reviewed-by: Satya Popuri <spopuri@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Dan Willemsen <dwillemsen@nvidia.com>

1 files changed, 29 insertions, 19 deletions

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 7821e41ab332..cf6ba6c1958e 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -30,8 +30,6 @@
 
 #include <asm/cputime.h>
 
-static atomic_t active_count = ATOMIC_INIT(0);
-
 struct cpufreq_interactive_cpuinfo {
 	struct timer_list cpu_timer;
 	int timer_idlecancel;
@@ -61,7 +59,9 @@ static spinlock_t up_cpumask_lock;
 static cpumask_t down_cpumask;
 static spinlock_t down_cpumask_lock;
 static struct mutex set_speed_lock;
+static struct mutex gov_state_lock;
 static struct kobject *interactive_kobj;
+static unsigned int active_count;
 
 /* Go to max speed when CPU load at or above this value. */
 #define DEFAULT_GO_MAXSPEED_LOAD 85
@@ -652,21 +652,25 @@ static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 				mod_timer(&pcpu->cpu_timer, jiffies + 2);
 		}
 
+		mutex_lock(&gov_state_lock);
+		active_count++;
 		/*
 		 * Do not register the idle hook and create sysfs
 		 * entries if we have already done so.
 		 */
-		if (atomic_inc_return(&active_count) > 1)
-			return 0;
-
-		rc = sysfs_create_group(cpufreq_global_kobject,
-				&interactive_attr_group);
-		interactive_kobj = kobject_create_and_add(
-					"gov_interactive",
-					cpufreq_global_kobject);
-		kobject_uevent(interactive_kobj, KOBJ_ADD);
-		if (rc)
-			return rc;
+		if (active_count == 1) {
+			rc = sysfs_create_group(cpufreq_global_kobject,
+					&interactive_attr_group);
+			interactive_kobj = kobject_create_and_add(
+						"gov_interactive",
+						cpufreq_global_kobject);
+			kobject_uevent(interactive_kobj, KOBJ_ADD);
+			if (rc) {
+				mutex_unlock(&gov_state_lock);
+				return rc;
+			}
+		}
+		mutex_unlock(&gov_state_lock);
 
 		break;
 
@@ -687,13 +691,18 @@ static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
 		}
 
 		flush_work(&freq_scale_down_work);
-		if (atomic_dec_return(&active_count) > 0)
-			return 0;
+		mutex_lock(&gov_state_lock);
+
+		active_count--;
+
+		if (active_count == 0) {
+			sysfs_remove_group(cpufreq_global_kobject,
+					&interactive_attr_group);
+			kobject_uevent(interactive_kobj, KOBJ_REMOVE);
+			kobject_put(interactive_kobj);
+		}
 
-		sysfs_remove_group(cpufreq_global_kobject,
-				&interactive_attr_group);
-		kobject_uevent(interactive_kobj, KOBJ_REMOVE);
-		kobject_put(interactive_kobj);
+		mutex_unlock(&gov_state_lock);
 
 		break;
 
@@ -771,6 +780,7 @@ static int __init cpufreq_interactive_init(void)
 	spin_lock_init(&up_cpumask_lock);
 	spin_lock_init(&down_cpumask_lock);
 	mutex_init(&set_speed_lock);
+	mutex_init(&gov_state_lock);
 
 	idle_notifier_register(&cpufreq_interactive_idle_nb);