static struct ttm_bo_user_object *ttm_bo_user_lookup(struct ttm_object_file
		*tfile, uint32_t handle) {
	struct ttm_base_object *base;

	base = ttm_base_object_lookup(tfile, handle);
	if (unlikely(base == NULL)) {
		printk(KERN_ERR "Invalid buffer object handle 0x%08lx.\n",
		       (unsigned long)handle);
		return NULL;
	}

	if (unlikely(base->object_type != ttm_buffer_type)) {
		ttm_base_object_unref(&base);
		printk(KERN_ERR "Invalid buffer object handle 0x%08lx.\n",
		       (unsigned long)handle);
		return NULL;
	}

	return container_of(base, struct ttm_bo_user_object, base);
}
/**
 * vmw_simple_resource_create_ioctl - Helper to set up an ioctl function to
 * create a struct vmw_simple_resource.
 *
 * @dev: Pointer to a struct drm device.
 * @data: Ioctl argument.
 * @file_priv: Pointer to a struct drm_file identifying the caller.
 * @func: Pointer to a struct vmw_simple_resource_func identifying the
 * simple resource type.
 *
 * Returns:
 *   0 if success,
 *   Negative error value on error.
 */
int
vmw_simple_resource_create_ioctl(struct drm_device *dev, void *data,
				 struct drm_file *file_priv,
				 const struct vmw_simple_resource_func *func)
{
	struct vmw_private *dev_priv = vmw_priv(dev);
	struct vmw_user_simple_resource *usimple;
	struct vmw_resource *res;
	struct vmw_resource *tmp;
	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
	struct ttm_operation_ctx ctx = {
		.interruptible = true,
		.no_wait_gpu = false
	};
	size_t alloc_size;
	size_t account_size;
	int ret;

	alloc_size = offsetof(struct vmw_user_simple_resource, simple) +
	  func->size;
	account_size = ttm_round_pot(alloc_size) + VMW_IDA_ACC_SIZE +
		TTM_OBJ_EXTRA_SIZE;

	ret = ttm_read_lock(&dev_priv->reservation_sem, true);
	if (ret)
		return ret;

	ret = ttm_mem_global_alloc(vmw_mem_glob(dev_priv), account_size,
				   &ctx);
	ttm_read_unlock(&dev_priv->reservation_sem);
	if (ret) {
		if (ret != -ERESTARTSYS)
			DRM_ERROR("Out of graphics memory for %s"
				  " creation.\n", func->res_func.type_name);

		goto out_ret;
	}

	usimple = kzalloc(alloc_size, GFP_KERNEL);
	if (!usimple) {
		ttm_mem_global_free(vmw_mem_glob(dev_priv),
				    account_size);
		ret = -ENOMEM;
		goto out_ret;
	}

	usimple->simple.func = func;
	usimple->account_size = account_size;
	res = &usimple->simple.res;
	usimple->base.shareable = false;
	usimple->base.tfile = NULL;

	/*
	 * From here on, the destructor takes over resource freeing.
	 */
	ret = vmw_simple_resource_init(dev_priv, &usimple->simple,
				       data, vmw_simple_resource_free);
	if (ret)
		goto out_ret;

	tmp = vmw_resource_reference(res);
	ret = ttm_base_object_init(tfile, &usimple->base, false,
				   func->ttm_res_type,
				   &vmw_simple_resource_base_release, NULL);

	if (ret) {
		vmw_resource_unreference(&tmp);
		goto out_err;
	}

	func->set_arg_handle(data, usimple->base.handle);
out_err:
	vmw_resource_unreference(&res);
out_ret:
	return ret;
}

/**
 * vmw_simple_resource_lookup - Look up a simple resource from its user-space
 * handle.
 *
 * @tfile: struct ttm_object_file identifying the caller.
 * @handle: The user-space handle.
 * @func: The struct vmw_simple_resource_func identifying the simple resource
 * type.
 *
 * Returns: Refcounted pointer to the embedded struct vmw_resource if
 * successfule. Error pointer otherwise.
 */
struct vmw_resource *
vmw_simple_resource_lookup(struct ttm_object_file *tfile,
			   uint32_t handle,
			   const struct vmw_simple_resource_func *func)
{
	struct vmw_user_simple_resource *usimple;
	struct ttm_base_object *base;
	struct vmw_resource *res;

	base = ttm_base_object_lookup(tfile, handle);
	if (!base) {
		DRM_ERROR("Invalid %s handle 0x%08lx.\n",
			  func->res_func.type_name,
			  (unsigned long) handle);
		return ERR_PTR(-ESRCH);
	}

	if (ttm_base_object_type(base) != func->ttm_res_type) {
		ttm_base_object_unref(&base);
		DRM_ERROR("Invalid type of %s handle 0x%08lx.\n",
			  func->res_func.type_name,
			  (unsigned long) handle);
		return ERR_PTR(-EINVAL);
	}

	usimple = container_of(base, typeof(*usimple), base);
	res = vmw_resource_reference(&usimple->simple.res);
	ttm_base_object_unref(&base);

	return res;
}