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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>
This commit is contained in:
Rafael J. Wysocki 2012-06-16 15:20:11 +02:00
parent dc7fd275ae
commit 6e797a0788
2 changed files with 33 additions and 2 deletions
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29
drivers/cpuidle/driver.c
View File

@ -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);
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);
}

6
include/linux/cpuidle.h
View File

@ -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; }