RE: [PATCH v2] RDMA/CMA: fix iWARP adapter TCP port space usage

Tung, Chien Tin
2010-07-07T18:10:39Z

> But the IB and IW port space is _already_ merged by the RDMA_CM. That's
> my point. So a solution that breaks this impacts transport-independent
> applications that use the rdma cm...
>
> > Could we prove a strong need for that short-cut?
> > If its really needed, one global RDMA_CM instance should be able
> > to achive that requirement. But wouldn't that go together with a waste
> > of unused transports resources (i.e., IB binds would create
> > and bind also TCP sockets..?).
> >
>
> My comment has nothing to do with TCP ports but rather RDMA ports as
> abstracted by the RDMA_CM. The RDMA_PS_TCP port space is shared among
> all the RDMA transports. So if you rdma_bind() to port space
> RDMA_PS_TCP, addr INADDR_ANY, port 9999, then it will bind the cm_id to
> all IB and IW providers for that address/port (note the providers don't
> really get called until rdma_listen()). Thus if you propose moving the
> bind operation down into the device providers, then the IB providers
> will also have to add this logic. Or some solution must be defined to
> keep the IB and IW port spaces common. Otherwise the RDMA_CM cannot
> support transport independent applications...

I didn't think about this before, a bit too focused on solving the iWARP side.
Bernard, what about letting RDMA CM allocate the socket and exposing it to
softiWARP?

Chien