Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

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

A number of significant enhancements to the ciss driver:

1. The FreeBSD driver was setting an interrupt coalesce delay of 1000us
for reasons that I can only speculate on. This was hurting everything
from lame sequential I/O "benchmarks" to legitimate filesystem metadata
operations that relied on serialized barrier writes. One of my
filesystem tests went from 35s to complete down to 6s.

2. Implemented the Performant transport method. Without the fix in
(1), I saw almost no difference. With it, my filesystem tests showed
another 5-10% improvement in speed. It was hard to measure CPU
utilization in any meaningful way, so it's not clear if there was a
benefit there, though there should have been since the interrupt handler
was reduced from 2 or more PCI reads down to 1.

3. Implemented MSI-X. Without any docs on this, I was just taking a
guess, and it appears to only work with the Performant method. This
could be a programming or understanding mistake on my part. While this
by itself made almost no difference to performance since the Performant
method already eliminated most of the synchronous reads over the PCI
bus, it did allow the CISS hardware to stop sharing its interrupt with
the USB hardware, which in turn allowed the driver to become decoupled
from the Giant-locked USB driver stack. This increased performance by
almost 20%. The MSI-X setup was done with 4 vectors allocated, but only
1 vector used since the performant method was told to only use 1 of 4
queues. Fiddling with this might make it work with the simpleq method,
not sure. I did not implement MSI since I have no MSI-specific hardware
in my test lab.

4. Improved the locking in the driver, trimmed some data structures.
This didn't improve test times in any measurable way, but it does look
like it gave a minor improvement to CPU usage when many
processes/threads were doing I/O in parallel. Again, this was hard to
accurately test.

Support passthru ioctl commands from 32bit binaries.

Clean up structure packing.

Make __packed attribute apply to structs themselves, not their typedefs.
GCC 3.4.2 issues warning about that.

use __packed/__aligned rather than GCC-specific __attribute__.

Add the 'ciss' driver, which supports the Compaq SmartRAID 5* family of
RAID controllers (5300, 532, 5i, etc.)

Thanks to Compaq and Yahoo! for support during the development of this
driver.

MFC after: 1 week