Commit 6e797a07 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent dc7fd275

drivers/cpuidle/driver.c

+28 −1
Original line number Diff line number Diff line
@@ -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 @@ void cpuidle_unregister_driver(struct cpuidle_driver *drv) 
	}



	spin_lock(&cpuidle_driver_lock);



	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);

}

include/linux/cpuidle.h

+5 −1
Original line number Diff line number Diff line
@@ -136,7 +136,9 @@ struct cpuidle_driver { 
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_idle_call(void) { return -ENODEV; } 
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; }