int mdev_register_device()

in mdev/mdev_core.c [124:194]

• 55 lines of code
• 14 McCabe index (conditional complexity)

int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
{
	int ret;
	struct mdev_parent *parent;
	char *env_string = "MDEV_STATE=registered";
	char *envp[] = { env_string, NULL };

	/* check for mandatory ops */
	if (!ops || !ops->supported_type_groups)
		return -EINVAL;
	if (!ops->device_driver && (!ops->create || !ops->remove))
		return -EINVAL;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	mutex_lock(&parent_list_lock);

	/* Check for duplicate */
	parent = __find_parent_device(dev);
	if (parent) {
		parent = NULL;
		ret = -EEXIST;
		goto add_dev_err;
	}

	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
	if (!parent) {
		ret = -ENOMEM;
		goto add_dev_err;
	}

	kref_init(&parent->ref);
	init_rwsem(&parent->unreg_sem);

	parent->dev = dev;
	parent->ops = ops;

	if (!mdev_bus_compat_class) {
		mdev_bus_compat_class = class_compat_register("mdev_bus");
		if (!mdev_bus_compat_class) {
			ret = -ENOMEM;
			goto add_dev_err;
		}
	}

	ret = parent_create_sysfs_files(parent);
	if (ret)
		goto add_dev_err;

	ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
	if (ret)
		dev_warn(dev, "Failed to create compatibility class link\n");

	list_add(&parent->next, &parent_list);
	mutex_unlock(&parent_list_lock);

	dev_info(dev, "MDEV: Registered\n");
	kobject_uevent_env(&dev->kobj, KOBJ_CHANGE, envp);

	return 0;

add_dev_err:
	mutex_unlock(&parent_list_lock);
	if (parent)
		mdev_put_parent(parent);
	else
		put_device(dev);
	return ret;
}