[openib-general] error return values from userspace calls

[Michael S. Tsirkin]

Quoting r. Pete Wyckoff <pw at osc.edu>:
> Then there's ibv_poll_cq that  returns +npolled on sucess, -1 on
> empty, -2 on error.  Why not EAGAIN instead of these custom codes?

Seems like thre's some mistake.
Should be 0 on empty, -1 on error (I'm not sure there *can* be an error from
ibv_poll_cq, need to look it up).

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MST