4 files changed, 24 insertions, 10 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 12fdd3987a36..199488576a05 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -156,7 +156,7 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
 
         if (dev->enabled)
                 return 0;
-        if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+        if (!cpuidle_get_driver() || !cpuidle_curr_governor)
                 return -EIO;
         if (!dev->state_count)
                 return -EINVAL;
@@ -207,7 +207,7 @@ void cpuidle_disable_device(struct cpuidle_device *dev)
 {
         if (!dev->enabled)
                 return;
-        if (!cpuidle_curr_driver || !cpuidle_curr_governor)
+        if (!cpuidle_get_driver() || !cpuidle_curr_governor)
                 return;
 
         dev->enabled = 0;
@@ -271,10 +271,11 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
 {
         int ret;
         struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+        struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
 
         if (!sys_dev)
                 return -EINVAL;
-        if (!try_module_get(cpuidle_curr_driver->owner))
+        if (!try_module_get(cpuidle_driver->owner))
                 return -EINVAL;
 
         init_completion(&dev->kobj_unregister);
@@ -284,7 +285,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
         per_cpu(cpuidle_devices, dev->cpu) = dev;
         list_add(&dev->device_list, &cpuidle_detected_devices);
         if ((ret = cpuidle_add_sysfs(sys_dev))) {
-                module_put(cpuidle_curr_driver->owner);
+                module_put(cpuidle_driver->owner);
                 return ret;
         }
 
@@ -325,6 +326,7 @@ EXPORT_SYMBOL_GPL(cpuidle_register_device);
 void cpuidle_unregister_device(struct cpuidle_device *dev)
 {
         struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
+        struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
 
         if (dev->registered == 0)
                 return;
@@ -340,7 +342,7 @@ void cpuidle_unregister_device(struct cpuidle_device *dev)
 
         cpuidle_resume_and_unlock();
 
-        module_put(cpuidle_curr_driver->owner);
+        module_put(cpuidle_driver->owner);
 }
 
 EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 9476ba33ee2c..33e50d556f17 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -9,7 +9,6 @@
 
 /* For internal use only */
 extern struct cpuidle_governor *cpuidle_curr_governor;
-extern struct cpuidle_driver *cpuidle_curr_driver;
 extern struct list_head cpuidle_governors;
 extern struct list_head cpuidle_detected_devices;
 extern struct mutex cpuidle_lock;
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 2257004fe33d..fd1601e3d125 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -14,7 +14,7 @@
 
 #include "cpuidle.h"
 
-struct cpuidle_driver *cpuidle_curr_driver;
+static struct cpuidle_driver *cpuidle_curr_driver;
 DEFINE_SPINLOCK(cpuidle_driver_lock);
 
 /**
@@ -40,13 +40,25 @@ int cpuidle_register_driver(struct cpuidle_driver *drv)
 EXPORT_SYMBOL_GPL(cpuidle_register_driver);
 
 /**
+ * cpuidle_get_driver - return the current driver
+ */
+struct cpuidle_driver *cpuidle_get_driver(void)
+{
+        return cpuidle_curr_driver;
+}
+EXPORT_SYMBOL_GPL(cpuidle_get_driver);
+
+/**
  * cpuidle_unregister_driver - unregisters a driver
  * @drv: the driver
  */
 void cpuidle_unregister_driver(struct cpuidle_driver *drv)
 {
-        if (!drv)
+        if (drv != cpuidle_curr_driver) {
+                WARN(1, "invalid cpuidle_unregister_driver(%s)\n",
+                        drv->name);
                 return;
+        }
 
         spin_lock(&cpuidle_driver_lock);
         cpuidle_curr_driver = NULL;
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 0ba9c8b8ee74..0310ffaec9df 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -47,10 +47,11 @@ static ssize_t show_current_driver(struct sysdev_class *class,
                                    char *buf)
 {
         ssize_t ret;
+        struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
 
         spin_lock(&cpuidle_driver_lock);
-        if (cpuidle_curr_driver)
-                ret = sprintf(buf, "%s\n", cpuidle_curr_driver->name);
+        if (cpuidle_driver)
+                ret = sprintf(buf, "%s\n", cpuidle_driver->name);
         else
                 ret = sprintf(buf, "none\n");
         spin_unlock(&cpuidle_driver_lock);