[openib-general] multicast code/merge status

[Sean Hefty]

> makes sense, so my suggestion is "leave this (using the ipoib qkey) to
> the user"

This is fine, but it may change when the user needs to make this choice.  E.g. 
when creating the QP, versus joining the multicast group, in order to support 
the valid options.  The selection also needs to be conveyed to the kernel 
somehow.  At this point, maybe we just need to start looking at specific 
implementations.

> I don't think there is any limitation today in the verbs layer,
> actually for our testing so far we patches the rdmacm not set the sig
> byte and use the ipoib (ie not override it in core/cma.c)  and we
> manage to interop fine with ipoib.

Maybe this shouldn't be allowed for any random application.  Perhaps there's a 
way to treat controlled qkeys similar to the privileged port space.

- Sean