[Devel] [PATCH VZ9 2/3] block/blk-cbt: allow multiple cbts in a single queue

[Pavel Tikhomirov]

>   static int cbt_ioc_init(struct block_device *bdev, struct blk_user_cbt_info __user *ucbt_ioc)
> @@ -632,16 +633,13 @@ static int cbt_ioc_init(struct block_device *bdev, struct blk_user_cbt_info __us
>   
>   	q = bdev_get_queue(bdev);
>   	mutex_lock(&cbt_mutex);
> -	if (q->cbt) {
> -		ret = -EBUSY;
> -		goto err_mtx;
> -	}
> +
>   	cbt = do_cbt_alloc(q, ci.ci_name, i_size_read(bdev->bd_inode), ci.ci_blksize);
>   	if (IS_ERR(cbt))
>   		ret = PTR_ERR(cbt);
>   	else
> -		rcu_assign_pointer(q->cbt, cbt);
> -err_mtx:
> +		list_add_tail_rcu(&q->cbt_list, &cbt->list);

should we check for cbt name collision?

> +
>   	mutex_unlock(&cbt_mutex);
>   	return ret;
>   }