[PATCH] nvme: Use NN for max_namespaces if MNAN is zero

[Christoph Hellwig]

On Fri, May 21, 2021 at 01:19:26PM -0700, Sagi Grimberg wrote:
>
>>> Forgot to mention: During testing dynamically adding namespaces it was
>>> possible to trigger the WARNINGs in the nvme_parse_ana_log(). Initially
>>> the subsystem started with 8 namespaces and during runtime another 8
>>> namespaces was added.
>>
>> The controller is required to have a non-zero MNAN value if it supports
>> ANA:
>>
>>    If the controller supports Asymmetric Namespace Access Reporting, then
>>    this field shall be set to a non-zero value that is less than or equal
>>    to the NN value.
>
> That was my thought exactly

I think we should add a sanity check for that and reject the broken
controller if that is not the case rather than working around it.