[openib-general] RFC userspace CMA
caitlinb at broadcom.com
Wed Oct 26 10:45:00 PDT 2005
> -----Original Message-----
> From: Sean Hefty [mailto:mshefty at ichips.intel.com]
> Sent: Wednesday, October 26, 2005 10:40 AM
> To: Caitlin Bestler
> Cc: Tom Tucker; openib
> Subject: Re: [openib-general] RFC userspace CMA
> Caitlin Bestler wrote:
> > How much logic is really in the RDMA CM?
> > If it is sufficiently small, which is what my expectation
> is, would it
> > make sense to simply make the IB CM and IW CM conform to the same
> > polymorphic interface? (Making the "RDMA CM" little more than a
> > re-directing inline function).
> > But if there is any substantial portion of common logic
> then the above
> > structure definitely makes sense.
> The kernel CMA is about 660 lines of code. It performs QP
> transitions for the user, abstracts device remove/addition,
> plus controls the mapping from IP to IB.
> (The mapping function makes use of external modules, such
> as ib_addr and
> In some places, the implementation of the API of the RDMA CM
> does little more than redirecting to the IW/IB CM, coupled
> with synchronization for device removal. However, it also
> handles the IB CM callbacks to provide simpler connection
So it sounds like the justification for the RDMA CM being
a distinct module is to centralize handling of device addition
and removal. Beyond that you are incorporating IB-specific
but device-independent logic. As a goal, the iWARP side
should be migrating there as well.
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