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);
+}
