[openib-general] Patch for review: ipath mmaped CQs, QPs, SRQs [1 of 2]

[Roland Dreier]

    Ralph> I agree. The kernel driver is careful to allocate the new
    Ralph> queue and copy the old contents to the new one
    Ralph> atomically. The issue is making sure the old queue isn't
    Ralph> still being used by some other thread. I guess if the
    Ralph> semantics for resize are that an error means the old mmap
    Ralph> is still valid but if the resize succeeds, the old mmap is
    Ralph> invalid, then there isn't an error recovery issue. All user
    Ralph> level threads lock before using the queue address so the
    Ralph> change of address is protected.

Those seem like the only sane semantics -- if the operation fails then
the state of the CQ shouldn't change.

 - R.