[Openib-windows] HCA: register_segment confusion

[Fab Tillier]

The register_segment function (mosal_iobuf.c at 74) is a bit confusing to say the
least.  What's the deal with the "fake_ro" checks, and trying to lock the pages
multiple times in different ways?  Can someone from Mellanox help explain what
the code is trying to do here?  What does the retry flag do?  What's going on
with the alternating read/write checks if modify right checks fail?

I started looking at adding support for large registrations, and I'm worried
that if I touch something it'll all fall over.  Memory locking should be a whole
lot simpler than what's going on here, and the comments don't really help.

Thanks,

- Fab