powercap: fix possible name leak in powercap_register_zone()

In the error path after calling dev_set_name(), the device
name is leaked. To fix this, calling dev_set_name() before
device_register(), and call put_device() if it returns error.

All the resources is released in powercap_release(), so it
can return from powercap_register_zone() directly.

Fixes: 75d2364 ("PowerCap: Add class driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Yang Yingliang

drivers/powercap/powercap_sys.c

@@ -530,9 +530,6 @@ struct powercap_zone *powercap_register_zone(
 	power_zone->name = kstrdup(name, GFP_KERNEL);
 	if (!power_zone->name)
 		goto err_name_alloc;
-	dev_set_name(&power_zone->dev, "%s:%x",
-					dev_name(power_zone->dev.parent),
-					power_zone->id);
 	power_zone->constraints = kcalloc(nr_constraints,
 					  sizeof(*power_zone->constraints),
 					  GFP_KERNEL);
@@ -555,9 +552,16 @@ struct powercap_zone *powercap_register_zone(
 	power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group;
 	power_zone->dev_attr_groups[1] = NULL;
 	power_zone->dev.groups = power_zone->dev_attr_groups;
+	dev_set_name(&power_zone->dev, "%s:%x",
+					dev_name(power_zone->dev.parent),
+					power_zone->id);
 	result = device_register(&power_zone->dev);
-	if (result)
-		goto err_dev_ret;
+	if (result) {
+		put_device(&power_zone->dev);
+		mutex_unlock(&control_type->lock);
+
+		return ERR_PTR(result);
+	}
 
 	control_type->nr_zones++;
 	mutex_unlock(&control_type->lock);