[openib-general] RFC: mthca: implement timewait by tracking QPNs

[Sean Hefty]

>Well, the idea of pushing timewait handling down into the low-level
>drivers seems strange to me.  I don't think any other stack or any
>other OS does anything like this.

I think the Windows IB stack may do something similar.

The difficulty is doing this at a higher level is that the QP must be destroyed
in order for the CQs / PD to be destroyed.  The IB CM already tracks timewait,
so could notify drivers when a QP can be re-used, but that requires connections
to go through the CM.  For stale connection handling, that may be a good thing
anyway, but there's nothing enforcing this today.

- Sean