MFC r326276:

various: general 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.

No functional change intended.

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

- Sprinkle const and static as appropriate.
- Fix whitespace bugs.
- Remove pointless returns in void functions.
- Nuke pointless switch cases mirroring the default.

MFC after: 3 days
Sponsored by: Bally Wulff Games & Entertainment GmbH

- Allow foot shooting with the resetconfig command via the -f option.
- Fix typos preventing -f to actually work with the create command.
- Initialize flags to zero rather than using stack garbage when handling
the grow command.

MFC after: 3 days
Sponsored by: Bally Wulff Games & Entertainment GmbH

Allow GEOM_VINUM to be statically compiled into the kernel.

Submitted by: gleb
MFC after: 3 days

Prevent an unlikely, but real double free issue in gvinum(8).

Coverity ID: 1018965

Fix warning when compiling with gcc46:
error: variable 'op' set but not used
error: variable 'cmd' set but not used

Approved by: dim
MFC after: 3 days

- fix duplicate "a a" in some comments

Submitted by: eadler
Approved by: simon
MFC after: 3 days

* Add the readline(3) API to libedit. The libedit versions of
{readline,history}.h are in /usr/include/edit so as to not conflict with
the GNU libreadline versions. To use the libedit readline(3) one should
add "-I/usr/include/edit" to their Makefile
(spelled "-I${DESTDIR}/${INCLUDEDIR}/edit" within the FreeBSD source tree).

* Enable its use in the BSD licensed utilities that support readline(3).

* To make it easier to sync libedit development with NetBSD, histedit.h
is moved into libedit's directory as history shows shown we keep merging
it into that location.

Obtained from: NetBSD
Sponsored by: Juniper Networks

Fix some more warnings found by clang.

Initialize variables before usage.

Found by: clang static analyzer
Found by: Coverity Prevent[tm] (CID 7736, 7760)

- Make function of finding an available drive name a macro.
- Move check of /dev/ prefix and copy into a function to save code duplication.
This also fixes a bug where the /dev/ prefix could not be used when creating
volumes on the command line.

Tested by: Niclas Zeising <niclas.zeising - at - gmail.com>

- Better wording in comment.

Suggested by: Christoph Mallon <christoph.mallon - at - gmx.de>

- Implement the grow command to make it easier for users to extend plexes
without having to understand all gvinum internals.
- Document the grow command in the manpage and update examples to use the
command where possible.

- Move logic for finding a unique drive name into its own routine for future
code reuse.

- Move out allocation part of different gvinum objects into its own routine and
make use of it in the gvinum userland code.

Import the gvinum work that have been done during and after Summer of Code 2007.
The work have been under testing and fixing since then, and it is mature enough
to be put into HEAD for further testing.

A lot have changed in this time, and here are the most important:
- Gvinum now uses one single workerthread instead of one thread for each
volume and each plex. The reason for this is that the previous scheme was
very complex, and was the cause of many of the bugs discovered in gvinum.
Instead, gvinum now uses one worker thread with an event queue, quite
similar to what used in gmirror.
- The rebuild/grow/initialize/parity check routines no longer runs in
separate threads, but are run as regular I/O requests with special flags.
This made it easier to support mounted growing and parity rebuild.
- Support for growing striped and raid5-plexes, meaning that one can extend the
volumes for these plex types in addition to the concat type. Also works while
the volume is mounted.
- Implementation of many of the missing commands from the old vinum:
attach/detach, start (was partially implemented), stop (was partially
implemented), concat, mirror, stripe, raid5 (shortcuts for creating volumes
with one plex of these organizations).
- The parity check and rebuild no longer goes between userland/kernel, meaning
that the gvinum command will not stay and wait forever for the rebuild to
finish. You can instead watch the status with the list command.
- Many problems with gvinum have been reported since 5.x, and some has been hard
to fix due to the complicated architecture. Hopefully, it should be more
stable and better handle edge cases that previously made gvinum crash.
- Failed drives no longer disappears entirely, but now leave behind a dummy
drive that makes sure the original state is not forgotten in case the system
is rebooted between drive failures/swaps.
- Update manpage to reflect new commands and extend it with some examples.

Sponsored by: Google Summer of Code 2007
Mentored by: le
Tested by: Rick C. Petty <rick-freebsd2008 -at- kiwi-computer.com>

Implement the 'resetconfig' command.

PR: kern/94835
Submitted by: Ulf Lilleengen <lulf@stud.ntnu.no>

Fix whitespace issues.

Pointed out by: joel@

Finally bring in what was produced during Google SoC 2005:

Add functions to rename objects and to move a subdisk from one drive
to another.

Add manual page (finally).

Bring up-to-date the online help.

Obtained from: Chris Jones <chris.jones@ualberta.ca>
Sponsored by: Google Summer of Code 2005
MFC in: 1 week

Clean up.

Remove unused functions.

Reduce indentation level by reverting the logic of the enclosing
conditional statement.

Implement 'setstate' to allow setting the state of drives and subdisks
for debugging and emergency purposes.

Implement checkparity/rebuildparity.

Allow 'create <filename>'.

Add gvinum, the geom_vinum userland tool.