[PATCH 3/3] nvmet: include all configured ports in discovery log page for unique discover controller

[Sagi Grimberg]

>>> To make it configurable.
>>> Unique discovery controllers show up in configfs just like any other
>>> subsystems.
>>> And with that we need to clarify the relationship between the discovery
>>> subsystem and the other subsystems, ie which subsystems should be 
>>> presented
>>> by this discovery subsystem.
>>>
>>> Linking the discovery subsystem into a given port makes it obvious that
>>> a) this port will be presenting a discovery subsystem
>>> and
>>> b) that the discovery subsystem will be presenting all subsystems
>>> configured on that port.
>>>
>>> The built-in mechanism for discovery subsystems was okay as long as the
>>> discovery subsystem was built-in, too.
>>> But with this patchset we're moving to an explicit configuration.
>>
>> Shouldn't we just require anything to be manually listed for this
>> case similar to how we configure referrals for the well known
>> discovery controller?
> 
> Which is what I've tried with this attempt.
> I did _not_ want to create a new configuration mechanism, but rather use 
> the existing ones.
> And the existing mechanism we have is linking subsystems to ports.
> 
> If we want to treat discovery subsystems differently (as you proposed) 
> we sure can have a different mechanism on how to configure it.
> But I wasn't sure if that's the direction we want to go.

What is the concern here? that it will break existing users with
introducing an additional configuration step?