[openib-general] IPoIB broadcast MC group membership

[Fabian Tillier]

If I understand the code correctly, IPoIB depends on the broadcast MC
group existing, as it only ever issues a MC join that does not create
the group to the SA.

First, is this correct?

Second, if so, how is IPoIB supposed to interact with subnet managers
that don't pre-create an empty broadcast group?

Shouldn't IPoIB first do a GET for the broadcast group, and use those
settings if it exist, otherwise create it?

Thanks,

- Fab