Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Start each of the license/copyright comments with /*-

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

(Forced commit- last commit was inadvertant in that it missed the comments)

Move TARGCTLIOALLOCUNIT to OTARGCTLIOALLOCUNIT, TARGCTLIOFREEUNIT
to OTARGCTLIOFREEUNIT and redefine old associated structure to be
old_ioc_alloc_unit- deprecation but preservation of binaries.

Add new structure for same- but this one contains a pointer to
user defined INQUIRY data so you can define what the target
device looks like to the outside world.

scsi_targetio.h

Add a TARGIODEBUG ioctl to allow for CAM_DEBUG_PERIPH tracing on
an opened target instance.

Back out the previous change to the queue(3) interface.
It was not discussed and should probably not happen.

Requested by: msmith and others

Change the way that the queue(3) structures are declared; don't assume that
the type argument to *_HEAD and *_ENTRY is a struct.

Suggested by: phk
Reviewed by: phk
Approved by: mdodd

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Checkpoint work on handling error conditions.

Handle errors reported through immediate notify ccbs. This includes
bus resets, BDR messages, and abort messages.

Properly setup CA conditions for errors such as uncorectable parity
in data phases, reselection failure, and IDE message received.

Add a mechanism for stalling the queue of transactions to a particular
initiator while a CA is in progress. Since we don't yet support
tagged I/O, this is largely just for show right now.

Properly bzero our softc at init time (oops).

Add more documentation on what all of the queues in our softc do.

Implement the control device for the "targ" target mode processor target
emulator so that instances can be dynamically added and removed from the
system.

Properly reference count peripheral instances so they are cleaned up when
destroyed by the control device.

Set a timeout for test unit ready commands. Before it was uninitialized
and could cause us to drop off the bus when no real timeout had occurred.

SCSI Peripheral drivers for CAM:

da - Direct Access Devices (disks, optical devices, SS disks)
cd - CDROM (or devices that can act like them, WORM, CD-RW, etc)
ch - Medium Changer devices.
sa - Sequential Access Devices (tape drives)
pass - Application pass-thru driver
targ - Target Mode "Processor Target" Emulator
pt - Processor Target Devices (scanners, cpus, etc.)

Submitted by: The CAM Team