[ofa-general] two questions about RDMA_CM_EVENT_TIMEWAIT_EXIT and the TimeWait state

[Sean Hefty]

>In 12.9.6 of the Infiniband Architecture v1.2, it seemed that a QP
>could enter the TimeWait state without having entered the Established
>state first, via the RTU timeout. Could a RDMA_CM_EVENT_TIMEWAIT_EXIT
>happen right after a RDMA_CM_EVENT_CONNECT_REQUEST without a
>RDMA_CM_EVENT_ESTABLISHED? If yes, our ULP would have to cleanup some
>resources in case RDMA_CM_EVENT_TIMEWAIT_EXIT happens on passive side.

Yes, it's possible to enter timewait without going through established.  I'd
have to walk through the code at this point to identify all of the cases.

Note that a lot (most?) connections between QPs are established out of band
using TCP, and these are not tracked by the CM or go through any sort of
timewait before potentially being reused.

- Sean