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

[Steve Wise]

Roland Dreier wrote:
>  > Hey Roland, are you ok with a device attribute to indicate hw-loopback
>  > support?
>
> Sigh, I guess so.  Can we have the rdma-cm handle this somewhat
> automagically, eg only choose devices that do handle loopback when
> binding/connecting to 127.0.0.1?  

That's the plan.

> Or maybe can we put the handling of
> this into the device-driver-specific iwcm methods, to fail
> listen/connect requests that are loopback?
>   

Is this only an iwarp issue?  IE do all IB devices support hw loopback?  
And will all future devices support it (IE is it an IBTA requirement)?

If so, then we could add a iwcm capabilities field maybe.  But currently 
there's no bind method.  We could add a bind method I suppose, but I'd 
rather do it with a simple capabilities.

> But if a device cap flag is what it takes, that's OK I guess.
>   

IMO the device cap flag is the way to go, and the rdma-cm should never 
bind 127.0.0.1 to a device that doesn't support loopback.

Steve.