[openib-general] ib_mad.h: ib_mad_reg_req question

[Roland Dreier]

> There are 2 SM classes: one for direct routed and the other for LID
> routed. Should these be handled separately (requiring 2 registrations
> for a client to get them all) or treated "special" and allow one
> registration to get them ?

> To me, this is a 2 part question:
> 1. Is there ever a need to get just one of these classes ? (I don't
> think so but want to be sure...)

Well, it's impossible to predict what users might want to do, so we
should never say never.  In fact I can imagine an SM that wants to
split the directed route discovery into a different process/thread
from LID routed MAD handling, and I don't see a good reason to force a
client like this to do the splitting between DR and LR MADs when the
core MAD layer could do it perfectly well.

> 2. If not, then is it acceptable to muddy the interface this way ?

I think the gain (client saves one registration call) is minimal, and
is outweighed by the loss in flexibility.  Also, I think the confusion
generated by having a "magic" interface where one class acts
differently from all other classes probably makes it not worth it to
people who would use the interface.

So I guess my vote on this feature would be "no" :)

 - R.