cpuidle: Fail cpuidle device registration if there is one already
Refuse to register a cpuidle device if the given CPU has a cpuidle
device already and print a message regarding it.
Without this, an attempt to register a new cpuidle device without
unregistering the existing one leads to the removal of the existing
cpuidle device without removing its sysfs interface.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 0835da4..56132e8 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -635,8 +635,14 @@ static void __cpuidle_device_init(struct cpuidle_device *dev)
static int __cpuidle_register_device(struct cpuidle_device *dev)
{
struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+ unsigned int cpu = dev->cpu;
int i, ret;
+ if (per_cpu(cpuidle_devices, cpu)) {
+ pr_info("CPU%d: cpuidle device already registered\n", cpu);
+ return -EEXIST;
+ }
+
if (!try_module_get(drv->owner))
return -EINVAL;
@@ -648,7 +654,7 @@ static int __cpuidle_register_device(struct cpuidle_device *dev)
dev->states_usage[i].disable |= CPUIDLE_STATE_DISABLED_BY_USER;
}
- per_cpu(cpuidle_devices, dev->cpu) = dev;
+ per_cpu(cpuidle_devices, cpu) = dev;
list_add(&dev->device_list, &cpuidle_detected_devices);
ret = cpuidle_coupled_register_device(dev);
