cam: Remove left-over sys/cdefs.h in sys/cam

These weren't removed when $FreeBSD$ was removed. They aren't needed and
now are a style(9) nonconformity.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

cam: clean up empty lines in .c and .h files

Cleanup LUN addition/removal.

- Make ctl_add_lun() synchronous. Asynchronous addition was used by
Copan's proprietary code long ago and never for upstream FreeBSD.
- Move LUN enable/disable calls from backends to CTL core.
- Serialize LUN modification and partially removal to avoid double frees.
- Slightly unify backends code.

MFC after: 2 weeks
Sponsored by: iXsystems, Inc.

Rework CTL frontend & backend options to use nv(3), allow creating multiple
ioctl frontend ports.

This revision introduces two changes to CTL:
- Changes the way options are passed to CTL_LUN_REQ and CTL_PORT_REQ ioctls.
Removes ctl_be_arg structure and associated logic and replaces it with
nv(3)-based logic for passing in and out arguments.
- Allows creating multiple ioctl frontend ports using either ctladm(8) or
ctld(8).
New frontend ports are represented by /dev/cam/ctl<pp>.<vp> nodes, eg /dev/cam/ctl5.3.
Those device nodes respond only to CTL_IO ioctl.

New command-line options for ctladm:
# creates new ioctl frontend port with using free pp and vp=0
ctladm port -c
# creates new ioctl frontend port with pp=10 and vp=0
ctladm port -c -O pp=10
# creates new ioctl frontend port with pp=11 and vp=12
ctladm port -c -O pp=11 -O vp=12
# removes port with number 4 (it's a "targ_port" number, not pp number)
ctladm port -r -p 4

New syntax for ctl.conf:
target ... {
port ioctl/<pp>
...
}

target ... {
port ioctl/<pp>/<vp>
...

Note: Most of this work was made by jceel@, thank you.

Submitted by: jceel
Reworked by: myself
Reviewed by: mav (earlier versions and recently during the rework)
Obtained from: FreeNAS and TrueOS
Relnotes: Yes
Sponsored by: iXsystems Inc.
Differential Revision: https://reviews.freebsd.org/D9299

sys/cam: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Add initial support for CTL module unloading.

It is only a first step and not perfect, but better then nothing.
The main blocker is CAM target frontend, that can not be unloaded,
since CAM does not have mechanism to unregister periph driver now.

MFC after: 2 weeks

Add LUN options to limit UNMAP and WRITE SAME sizes.

CTL itself has no limits on on UNMAP and WRITE SAME sizes. But depending
on backends large requests may take too much time. To avoid that new
configuration options allow to hint initiator maximal sizes it should not
exceed.

MFC after: 2 weeks

Remove some control_softc references.

Allow LUN options modification via CTL_LUNREQ_MODIFY.

Not all changes take effect, but that is a different question.

Drop "internal" CTL frontend.

Its idea was to be a simple initiator and execute several commands from
kernel level, but FreeBSD never had consumer for that functionality,
while its implementation polluted many unrelated places..

Reduce number of places where global control_softc is used.

At some point we may want to have several CTL instances, and that is not
really impossible.

MFC after: 2 weeks

Improve CTL_BEARG_* flags support, including optional values copyout.

Make options KPI more generic to allow it to be used for ports too,
not only for LUNs.

Implement small KPI to access LUN options instead doing it by hands.

MFC after: 2 weeks

Remove ctl(4) from GENERIC. Also remove 'options CTL_DISABLE'
and kern.cam.ctl.disable tunable; those were introduced as a workaround
to make it possible to boot GENERIC on low memory machines.

With ctl(4) being built as a module and automatically loaded by ctladm(8),
this makes CTL work out of the box.

Reviewed by: ken
Sponsored by: FreeBSD Foundation

Add a loader tunable, kern.cam.ctl.disable, that will disable
loading CTL. This may be useful in very low memory installations.

MFC after: 3 days

Change the SCSI INQUIRY peripheral qualifier that CTL reports for LUNs
that don't exist.

Anecdotal evidence indicates that it is better to return 011b (bad LUN)
than 001b (LUN offline). However, this change also gives the user a
sysctl/tunable, kern.cam.ctl.inquiry_pq_no_lun, to override the change
and return to the previous behavior. (The previous behavior was to
return 001b, or LUN offline.)

ctl.c: Change the default inquiry peripheral qualifier to 011b,
and add a sysctl and tunable to allow the user to change
it back to 001b if needed.

Don't insert a Copan copyright statement in the inquiry
data. The copyright statements on the files are
sufficient.

ctl_private.h: Add sysctl variable context to the CTL softc.

ctl_cmd_table.c,
ctl_frontend_internal.c,
ctl_frontend.c,
ctl_backend.c,
ctl_error.c: Include sys/sysctl.h.

MFC after: 3 days

Add the CAM Target Layer (CTL).

CTL is a disk and processor device emulation subsystem originally written
for Copan Systems under Linux starting in 2003. It has been shipping in
Copan (now SGI) products since 2005.

It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
available under a BSD-style license. The intent behind the agreement was
that Spectra would work to get CTL into the FreeBSD tree.

Some CTL features:

- Disk and processor device emulation.
- Tagged queueing
- SCSI task attribute support (ordered, head of queue, simple tags)
- SCSI implicit command ordering support. (e.g. if a read follows a mode
select, the read will be blocked until the mode select completes.)
- Full task management support (abort, LUN reset, target reset, etc.)
- Support for multiple ports
- Support for multiple simultaneous initiators
- Support for multiple simultaneous backing stores
- Persistent reservation support
- Mode sense/select support
- Error injection support
- High Availability support (1)
- All I/O handled in-kernel, no userland context switch overhead.

(1) HA Support is just an API stub, and needs much more to be fully
functional.

ctl.c: The core of CTL. Command handlers and processing,
character driver, and HA support are here.

ctl.h: Basic function declarations and data structures.

ctl_backend.c,
ctl_backend.h: The basic CTL backend API.

ctl_backend_block.c,
ctl_backend_block.h: The block and file backend. This allows for using
a disk or a file as the backing store for a LUN.
Multiple threads are started to do I/O to the
backing device, primarily because the VFS API
requires that to get any concurrency.

ctl_backend_ramdisk.c: A "fake" ramdisk backend. It only allocates a
small amount of memory to act as a source and sink
for reads and writes from an initiator. Therefore
it cannot be used for any real data, but it can be
used to test for throughput. It can also be used
to test initiators' support for extremely large LUNs.

ctl_cmd_table.c: This is a table with all 256 possible SCSI opcodes,
and command handler functions defined for supported
opcodes.

ctl_debug.h: Debugging support.

ctl_error.c,
ctl_error.h: CTL-specific wrappers around the CAM sense building
functions.

ctl_frontend.c,
ctl_frontend.h: These files define the basic CTL frontend port API.

ctl_frontend_cam_sim.c: This is a CTL frontend port that is also a CAM SIM.
This frontend allows for using CTL without any
target-capable hardware. So any LUNs you create in
CTL are visible in CAM via this port.

ctl_frontend_internal.c,
ctl_frontend_internal.h:
This is a frontend port written for Copan to do
some system-specific tasks that required sending
commands into CTL from inside the kernel. This
isn't entirely relevant to FreeBSD in general,
but can perhaps be repurposed.

ctl_ha.h: This is a stubbed-out High Availability API. Much
more is needed for full HA support. See the
comments in the header and the description of what
is needed in the README.ctl.txt file for more
details.

ctl_io.h: This defines most of the core CTL I/O structures.
union ctl_io is conceptually very similar to CAM's
union ccb.

ctl_ioctl.h: This defines all ioctls available through the CTL
character device, and the data structures needed
for those ioctls.

ctl_mem_pool.c,
ctl_mem_pool.h: Generic memory pool implementation used by the
internal frontend.

ctl_private.h: Private data structres (e.g. CTL softc) and
function prototypes. This also includes the SCSI
vendor and product names used by CTL.

ctl_scsi_all.c,
ctl_scsi_all.h: CTL wrappers around CAM sense printing functions.

ctl_ser_table.c: Command serialization table. This defines what
happens when one type of command is followed by
another type of command.

ctl_util.c,
ctl_util.h: CTL utility functions, primarily designed to be
used from userland. See ctladm for the primary
consumer of these functions. These include CDB
building functions.

scsi_ctl.c: CAM target peripheral driver and CTL frontend port.
This is the path into CTL for commands from
target-capable hardware/SIMs.

README.ctl.txt: CTL code features, roadmap, to-do list.

usr.sbin/Makefile: Add ctladm.

ctladm/Makefile,
ctladm/ctladm.8,
ctladm/ctladm.c,
ctladm/ctladm.h,
ctladm/util.c: ctladm(8) is the CTL management utility.
It fills a role similar to camcontrol(8).
It allow configuring LUNs, issuing commands,
injecting errors and various other control
functions.

usr.bin/Makefile: Add ctlstat.

ctlstat/Makefile
ctlstat/ctlstat.8,
ctlstat/ctlstat.c: ctlstat(8) fills a role similar to iostat(8).
It reports I/O statistics for CTL.

sys/conf/files: Add CTL files.

sys/conf/NOTES: Add device ctl.

sys/cam/scsi_all.h: To conform to more recent specs, the inquiry CDB
length field is now 2 bytes long.

Add several mode page definitions for CTL.

sys/cam/scsi_all.c: Handle the new 2 byte inquiry length.

sys/dev/ciss/ciss.c,
sys/dev/ata/atapi-cam.c,
sys/cam/scsi/scsi_targ_bh.c,
scsi_target/scsi_cmds.c,
mlxcontrol/interface.c: Update for 2 byte inquiry length field.

scsi_da.h: Add versions of the format and rigid disk pages
that are in a more reasonable format for CTL.

amd64/conf/GENERIC,
i386/conf/GENERIC,
ia64/conf/GENERIC,
sparc64/conf/GENERIC: Add device ctl.

i386/conf/PAE: The CTL frontend SIM at least does not compile
cleanly on PAE.

Sponsored by: Copan Systems, SGI and Spectra Logic
MFC after: 1 month