PM / cpuidle: Add driver reference counter
Add a reference counter for the cpuidle driver, so that it can't
be unregistered when it is in use.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 40cd3f3..58bf3b1 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -16,6 +16,7 @@
static struct cpuidle_driver *cpuidle_curr_driver;
DEFINE_SPINLOCK(cpuidle_driver_lock);
+int cpuidle_driver_refcount;
static void __cpuidle_register_driver(struct cpuidle_driver *drv)
{
@@ -89,8 +90,34 @@
}
spin_lock(&cpuidle_driver_lock);
- cpuidle_curr_driver = NULL;
+
+ if (!WARN_ON(cpuidle_driver_refcount > 0))
+ cpuidle_curr_driver = NULL;
+
spin_unlock(&cpuidle_driver_lock);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister_driver);
+
+struct cpuidle_driver *cpuidle_driver_ref(void)
+{
+ struct cpuidle_driver *drv;
+
+ spin_lock(&cpuidle_driver_lock);
+
+ drv = cpuidle_curr_driver;
+ cpuidle_driver_refcount++;
+
+ spin_unlock(&cpuidle_driver_lock);
+ return drv;
+}
+
+void cpuidle_driver_unref(void)
+{
+ spin_lock(&cpuidle_driver_lock);
+
+ if (!WARN_ON(cpuidle_driver_refcount <= 0))
+ cpuidle_driver_refcount--;
+
+ spin_unlock(&cpuidle_driver_lock);
+}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 8570012..27cfced 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -136,7 +136,9 @@
extern void disable_cpuidle(void);
extern int cpuidle_idle_call(void);
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
-struct cpuidle_driver *cpuidle_get_driver(void);
+extern struct cpuidle_driver *cpuidle_get_driver(void);
+extern struct cpuidle_driver *cpuidle_driver_ref(void);
+extern void cpuidle_driver_unref(void);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);
@@ -157,6 +159,8 @@
static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
+static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
+static inline void cpuidle_driver_unref(void) {}
static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
static inline int cpuidle_register_device(struct cpuidle_device *dev)
{return -ENODEV; }