[openib-general] Reregister Memory Region Verb

[Roland Dreier]

    Galen> I would like to be able to extend an existing registration
    Galen> such that the driver would take advantage of the fact that
    Galen> part of the extended registration is already registered,
    Galen> i.e. only the "new" memory would be pinned and made
    Galen> resident. Also, it would be necessary that this operation
    Galen> wouldn't invalidate operations in progress on the original
    Galen> registration or the call would block until pending
    Galen> operations had completed, although we would prefer that it
    Galen> wouldn't block if possible ;-) .

Hmm, this is a problem.  The IB spec specifically requires that the
reregister MR operation behave like a deregister followed by
register.  In C11-21, the spec says that operations in progress during
a reregister must get an error because of the deregistration.

 - R.