[openib-general] Reuse pd amd mr

[Roland Dreier]

    Changqing> Roland: I did exactly what you said with two cards on a
    Changqing> node, however, if I use the two physical channels for
    Changqing> Message striping, 99% of the test passed, but for some
    Changqing> condition, I got IBV_WC_RETRY_EXC_ERR, or the code Just
    Changqing> hangs there with no sending completion(ibv_poll_cq
    Changqing> returns 0). Do you think this is a firware issue, Or
    Changqing> the driver issue ?

'retries exceeded' means that the transport retry count was
exceeded, so most likely your timeout is set too low.

Without seeing your code, I couldn't begin to say why you don't see a
send completion.  If you are absolutely positive that you post a send
and you never see a completion for that send, then I guess it is a
firmware or hardware problem.

 - R.