struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq,
					bool zcopy)
{
	struct vhost_ubuf_ref *ubufs;
	/* No zero copy backend? Nothing to count. */
	if (!zcopy)
		return NULL;
	ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL);
	if (!ubufs)
		return ERR_PTR(-ENOMEM);
	kref_init(&ubufs->kref);
	init_waitqueue_head(&ubufs->wait);
	ubufs->vq = vq;
	return ubufs;
}

Unknown