[ewg] bug 1918 - openmpi broken due to rdma-cm changes

[Sean Hefty]

>OpenMPI uses rdma_bind_addr() to figure out which ip addresses are valid
>for which IB devices.   This logic is now broken.  Regardless of whether
>OpenMPI should use another method for determining which IP address
>belong to which interfaces, we should probably rethink whether we're
>breaking rdma-cm semantics in a bad way on a point release.

The changes to the rdma_cm have been merged upstream.  These were fixes
specifically to enable using the loopback address with RDMA devices.

At first thought, we can extend enum ib_device_cap_flags to indicate if a device
supports loopback capabilities or not.  The rdma_cm could then skip over such
devices when dealing with a loopback address. 

- Sean