Hi Ming On 09/29/2018 10:49 AM, Ming Lei wrote: > Looks both blk_mq_sysfs_register() and blk_mq_debugfs_register_hctx() > are removed from the path of blk_mq_init_allocated_queue(), so where are > the two registered for a freshly new queue? Initially, both of them are registered by following path. __device_add_disk -> blk_register_queue if (q->mq_ops) { __blk_mq_register_dev(dev, q); blk_mq_debugfs_register(q); } blk_mq_init_allocated_queue won't do any thing. Thanks Jianchao