Re: [PATCH v2 3/3] nvme: prevent ioq creation for discovery controllers

[Damien Le Moal]

On 7/3/25 3:09 AM, Kamaljit Singh wrote:
> Hi Damien,
>  
> On 7/1/25 19:18, Damien Le Moal wrote:
>>>   /*
>>> - * An admin controller has one admin queue, but no I/O queues.
>>> + * An admin or discovery controller has one admin queue, but no I/O queues.
>>>    * Override queue_count so it only creates an admin queue.
>>>    */
>>>   void nvme_override_prohibited_io_queues(struct nvme_ctrl *ctrl)
>>>   {
>>> -     if (nvme_admin_ctrl(ctrl))
>>> +     if (nvme_admin_ctrl(ctrl) || nvme_discovery_ctrl(ctrl))
>>>                ctrl->queue_count = 1;
>>>   }
>>>   EXPORT_SYMBOL_GPL(nvme_override_prohibited_io_queues);
>>
>> Repeating comment on patch 1. Can't we do this in nvme_init_subsystem() or may
>> be better, in nvme_set_queue_count() or nvme_init_ctrl_finish() ?
> nvme_set_queue_count() won’t even be called in this case, as its only used to
> configure IO queues, which are not being configured for an admin controller.
>  
> If we move nvme_override_prohibited_io_queues() up the stack into either of your
> suggested core.c functions, it will affect apple & fc drivers, which I don’t have any
> means of testing. Any suggestions?

Why would the controller vendor or its fabric matter ?
If the controller type is admin or discovery, you want queue_count set to 1. So
I do not think there is any problem.


-- 
Damien Le Moal
Western Digital Research