[PATCH] nvme: allow ANA support to be independent of native multipathing

[hch@lst.de (Christoph Hellwig)]

On Fri, Nov 16, 2018@10:40:40AM +0100, Hannes Reinecke wrote:
>>> Introduce ability to always re-read ANA log page as required due to ANA
>>> error and make current ANA state available via sysfs -- even if native
>>> multipathing is disabled on the host (e.g. nvme_core.multipath=N).
>>
>> The first part I could see, but I still want to make it conditional
>> in some way as nvme is going into deeply embedded setups, and I don't
>> want to carry the weight of the ANA code around for everyone.
>>
> Can you clarify this a bit?
> We _do_ have the NVME multipath config option to deconfigure the whole 
> thing during compile time; that isn't influenced with this patch.
> So are you worried about the size of the ANA implementation itself?
> Or are you worried about the size of the ANA structures?

I just see the next step of wanting to move ANA code into the core
which is implied above.
>
>> The second I fundamentally disagree with.  And even if you found agreement
>> it would have to be in a separate patch as it is a separate feature.
>>
> Why? Where's the problem with re-reading the ANA log pages if we get an 
> event indicating that we should?

"second" here means the sysfs file.