static void ib_uverbs_add_one(struct ib_device *device)
{
	int devnum;
	dev_t base;
	struct ib_uverbs_device *uverbs_dev;
	int ret;

	if (!device->alloc_ucontext)
		return;

	uverbs_dev = kzalloc(sizeof *uverbs_dev, GFP_KERNEL);
	if (!uverbs_dev)
		return;

	ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
	if (ret) {
		kfree(uverbs_dev);
		return;
	}

	atomic_set(&uverbs_dev->refcount, 1);
	init_completion(&uverbs_dev->comp);
	uverbs_dev->xrcd_tree = RB_ROOT;
	mutex_init(&uverbs_dev->xrcd_tree_mutex);
	kobject_init(&uverbs_dev->kobj, &ib_uverbs_dev_ktype);
	mutex_init(&uverbs_dev->lists_mutex);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_events_file_list);

	spin_lock(&map_lock);
	devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
	if (devnum >= IB_UVERBS_MAX_DEVICES) {
		spin_unlock(&map_lock);
		devnum = find_overflow_devnum();
		if (devnum < 0)
			goto err;

		spin_lock(&map_lock);
		uverbs_dev->devnum = devnum + IB_UVERBS_MAX_DEVICES;
		base = devnum + overflow_maj;
		set_bit(devnum, overflow_map);
	} else {
		uverbs_dev->devnum = devnum;
		base = devnum + IB_UVERBS_BASE_DEV;
		set_bit(devnum, dev_map);
	}
	spin_unlock(&map_lock);

	rcu_assign_pointer(uverbs_dev->ib_dev, device);
	uverbs_dev->num_comp_vectors = device->num_comp_vectors;

	cdev_init(&uverbs_dev->cdev, NULL);
	uverbs_dev->cdev.owner = THIS_MODULE;
	uverbs_dev->cdev.ops = device->mmap ? &uverbs_mmap_fops : &uverbs_fops;
	uverbs_dev->cdev.kobj.parent = &uverbs_dev->kobj;
	kobject_set_name(&uverbs_dev->cdev.kobj, "uverbs%d", uverbs_dev->devnum);
	if (cdev_add(&uverbs_dev->cdev, base, 1))
		goto err_cdev;

	uverbs_dev->dev = device_create(uverbs_class, device->dma_device,
					uverbs_dev->cdev.dev, uverbs_dev,
					"uverbs%d", uverbs_dev->devnum);
	if (IS_ERR(uverbs_dev->dev))
		goto err_cdev;

	if (device_create_file(uverbs_dev->dev, &dev_attr_ibdev))
		goto err_class;
	if (device_create_file(uverbs_dev->dev, &dev_attr_abi_version))
		goto err_class;

	ib_set_client_data(device, &uverbs_client, uverbs_dev);

	return;

err_class:
	device_destroy(uverbs_class, uverbs_dev->cdev.dev);

err_cdev:
	cdev_del(&uverbs_dev->cdev);
	if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
		clear_bit(devnum, dev_map);
	else
		clear_bit(devnum, overflow_map);

err:
	if (atomic_dec_and_test(&uverbs_dev->refcount))
		ib_uverbs_comp_dev(uverbs_dev);
	wait_for_completion(&uverbs_dev->comp);
	kobject_put(&uverbs_dev->kobj);
	return;
}
static void ib_uverbs_add_one(struct ib_device *device)
{
	int devnum;
	dev_t base;
	struct ib_uverbs_device *uverbs_dev;
	int ret;

	if (!device->alloc_ucontext)
		return;

	uverbs_dev = kzalloc(sizeof *uverbs_dev, GFP_KERNEL);
	if (!uverbs_dev)
		return;

	ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
	if (ret) {
		kfree(uverbs_dev);
		return;
	}

	atomic_set(&uverbs_dev->refcount, 1);
	init_completion(&uverbs_dev->comp);
	uverbs_dev->xrcd_tree = RB_ROOT;
	mutex_init(&uverbs_dev->xrcd_tree_mutex);
	kobject_init(&uverbs_dev->kobj, &ib_uverbs_dev_ktype);
	mutex_init(&uverbs_dev->lists_mutex);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
	INIT_LIST_HEAD(&uverbs_dev->uverbs_events_file_list);

	spin_lock(&map_lock);
	devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
	if (devnum >= IB_UVERBS_MAX_DEVICES) {
		spin_unlock(&map_lock);
		devnum = find_overflow_devnum();
		if (devnum < 0)
			goto err;

		spin_lock(&map_lock);
		uverbs_dev->devnum = devnum + IB_UVERBS_MAX_DEVICES;
		base = devnum + overflow_maj;
		set_bit(devnum, overflow_map);
	} else {
		uverbs_dev->devnum = devnum;
		base = devnum + IB_UVERBS_BASE_DEV;
		set_bit(devnum, dev_map);
	}
	spin_unlock(&map_lock);

	rcu_assign_pointer(uverbs_dev->ib_dev, device);
	uverbs_dev->num_comp_vectors = device->num_comp_vectors;

	cdev_init(&uverbs_dev->cdev, NULL);
	uverbs_dev->cdev.owner = THIS_MODULE;
	uverbs_dev->cdev.ops = device->mmap ? &uverbs_mmap_fops : &uverbs_fops;
	uverbs_dev->cdev.kobj.parent = &uverbs_dev->kobj;
	kobject_set_name(&uverbs_dev->cdev.kobj, "uverbs%d", uverbs_dev->devnum);
	if (cdev_add(&uverbs_dev->cdev, base, 1))
		goto err_cdev;

	uverbs_dev->dev = device_create(uverbs_class, device->dma_device,
					uverbs_dev->cdev.dev, uverbs_dev,
					"uverbs%d", uverbs_dev->devnum);
	if (IS_ERR(uverbs_dev->dev))
		goto err_cdev;

	if (device_create_file(uverbs_dev->dev, &dev_attr_ibdev))
		goto err_class;
	if (device_create_file(uverbs_dev->dev, &dev_attr_abi_version))
		goto err_class;

	ib_set_client_data(device, &uverbs_client, uverbs_dev);

	return;

err_class:
	device_destroy(uverbs_class, uverbs_dev->cdev.dev);

err_cdev:
	cdev_del(&uverbs_dev->cdev);
	if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
		clear_bit(devnum, dev_map);
	else
		clear_bit(devnum, overflow_map);

err:
	if (atomic_dec_and_test(&uverbs_dev->refcount))
		ib_uverbs_comp_dev(uverbs_dev);
	wait_for_completion(&uverbs_dev->comp);
	kobject_put(&uverbs_dev->kobj);
	return;
}