From 6e797a078824b30afbfae6cc4b1c2b21c51761ef Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 16 Jun 2012 15:20:11 +0200 Subject: 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 --- drivers/cpuidle/driver.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c index 40cd3f3024d..58bf3b1ac9c 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 @@ 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); +} -- cgit v1.2.3-70-g09d2