[openib-general] RFC userspace CMA

[Sean Hefty]

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 
sa_query.)

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 notification.

- Sean