Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Style: NO_MAN doesn't need any value.

This test can run now.

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