Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

s/sigval/sival/g

This will not compile without:
http://www.ambrisko.com/doug/listio_kqueue/listio_kqueue.patch

Note: it is a good idea to run this against a physical drive to
exercise the physio fast path (ie. lio_kqueue /dev/<something safe>)
This will ensure op's counting per LIO request is correct. It is
currently broken the above patch fixes it.

Sponsored by: IronPort