Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC: r248804

deferal -> deferral

MFC: r248891

Pass correct parameter to CTR5() in bus_dmamap_load_uio.

MFC: r248892

Do not add 1 to nsegs before passing to CTR5(), since nsegs
has already been incremented before these calls.

MFC: r248893

Add CTR5() to bus_dmamap_load_ccb, similar to other bus_dmamap_load_*
functions.

MFC: r248896

Add bus_dmamap_load_bio for non-CAM disk drivers that wish to enable
unmapped I/O.

MFC: r249025

Add support for XPT_CONT_TARGET_IO CCBs in _bus_dmamap_load_ccb().

Declare CCB types in their respective switch blocks.

MFC: r249538

Some compilers issue a warning when wider integer is casted to narrow
pointer. Supposedly shut down the warning by casting through
uintptr_t.

MFC: r251221

Move an assertion to the right spot; only bus_dmamap_load_mbuf(9)
requires a pkthdr being present but that's not the case for either
_bus_dmamap_load_mbuf_sg() or bus_dmamap_load_mbuf_sg(9).

Merge the second part of the unmapped I/O changes. This enables the
infrastructure in the block layer and UFS filesystem as well as a few
drivers. The list of MFC revisions is long, so I won't quote changelogs.

r248508,248510,248511,248512,248514,248515,248516,248517,248518,
248519,248520,248521,248550,248568,248789,248790,249032,250936

Submitted by: kib
Approved by: kib
Obtained from: Netflix

Big MFC of the physbio changes necessary for unmapped I/O. These changes
have been in production at Netflix for several months with significant
success.

MFC r246713:

Reform the busdma API so that new types may be added without modifying
every architecture's busdma_machdep.c. It is done by unifying the
bus_dmamap_load_buffer() routines so that they may be called from MI
code. The MD busdma is then given a chance to do any final processing
in the complete() callback.

MFC r249538:
Some compilers issue a warning when wider integer is casted to narrow
pointer. Supposedly shut down the warning by casting through
uintptr_t.

MFC r251479:
Simplify the checking of flags for cam_periph_mapmem(). This gets rid of
a lot of code redundancy and grossness at very minor expense.

MFC r251837:
MFC r251842:
Add infrastructure for doing compatibility shims, as has been sorely
needed for the last 10 years. Far too much of the internal API is
exposed, and every small adjustment causes applications to stop working.
To kick this off, bump the API version to 0x17 as should have been done
with r246713, but add shims to compensate. Thanks to the shims, there
should be no visible change in application behavior.

Submitted by: kib, jeffr
Approved by: kib
Obtained from: Netflix

Reform the busdma API so that new types may be added without modifying
every architecture's busdma_machdep.c. It is done by unifying the
bus_dmamap_load_buffer() routines so that they may be called from MI
code. The MD busdma is then given a chance to do any final processing
in the complete() callback.

The cam changes unify the bus_dmamap_load* handling in cam drivers.

The arm and mips implementations are updated to track virtual
addresses for sync(). Previously this was done in a type specific
way. Now it is done in a generic way by recording the list of
virtuals in the map.

Submitted by: jeff (sponsored by EMC/Isilon)
Reviewed by: kan (previous version), scottl,
mjacob (isp(4), no objections for target mode changes)
Discussed with: ian (arm changes)
Tested by: marius (sparc64), mips (jmallet), isci(4) on x86 (jharris),
amd64 (Fabian Keil <freebsd-listen@fabiankeil.de>)