MFC r267667:
use .Mt to mark up email addresses consistently (part1)

PR: 191174
Submitted by: Franco Fichtner <franco at lastsummer.de>

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

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

Sort sections.

Typo.

- Enable 16byte commands.
- Fix printf warnings on 64bit architectures.
- Accept 'k', 'm' and etc. for -s option.

Reviewed by: njl

mdoc(7) police: markup overhaul.

Approved by: re

New SCSI target emulator code

This code allows a user program to enable target mode on a SIM and
then emulate any number of devices (disks, tape drives, etc.) All
decisions about device behavior (UA, CA, inquiry response) are left
to the usermode program and the kernel driver is merely a conduit
for CCBs. This enables multiple concurrent target emulators, each
using its own backing store and IO model.

Also included is a user program that emulates a disk (RBC) using a
file as a backing store. This provides functionality similar to
md(4) at the CAM layer.

Code has been tested on ahc(4) and should also work on isp(4) (and
other SIMs that gain target mode support). It is a complete rewrite
of /sys/cam/scsi_target* and /usr/share/examples/scsi_target.

Design, comments from: gibbs
Supported by: Cryptography Research
Approved by: re