Re: [PATCH 11/12] nvme-pci: split the initial probe from the rest path

[Christoph Hellwig <hch@lst.de>]

On Wed, Nov 09, 2022 at 05:14:02AM +0200, Sagi Grimberg wrote:
>> -		if (dev->online_queues > 1) {
>> -			nvme_pci_alloc_tag_set(dev);
>> -			nvme_dbbuf_set(dev);
>> -		} else {
>> -			dev_warn(dev->ctrl.device, "IO queues not created\n");
>> -		}
>> +		dev_warn(dev->ctrl.device, "IO queues lost\n");
>> +		nvme_mark_namespaces_dead(&dev->ctrl);
>> +		nvme_start_queues(&dev->ctrl);
>> +		nvme_remove_namespaces(&dev->ctrl);
>
> Is this needed? isn't nvme_remove coming soon?
> In fact, shouldn't all these calls be in nvme_remove?

This handles the case where a controller controller does not have I/O
queues. For controllers that never had them (e.g. admin controllers)
none of the three calls above is needed, but they deal with the
case where a controller had queues, but they are going away.  I'm
not sure if that can happen, but it keeps the behavior of the existing
code.  Keith wrote it to deal with Intel controllers that can be in
a degraded state where having the admin queue live even without I/O
queues allows updating the firmware, so he might know more.