MFC r272193

  Allow the PIC's IMR register to be read before ICW initialisation.

  As of git submit e179f6914152eca9, the Linux kernel does a simple
  probe of the PIC by writing a pattern to the IMR and then reading it
  back, prior to the init sequence of ICW words.

  The bhyve PIC emulation wasn't allowing the IMR to be read until
  the ICW sequence was complete. This limitation isn't required so
  relax the test.

  With this change, Linux kernels 3.15-rc2 and later won't hang
  on boot when calibrating the local APIC.

Approved by: re (gjb)
MFC r272027:

Hardware driver update from Mellanox Technologies, including:
 - improved performance
 - better stability
 - new features
 - bugfixes

Supported HCAs:
 - ConnectX-2
 - ConnectX-3
 - ConnectX-3 Pro

NOTE:
  - TSO feature needs r271946, which is not yet merged.

Sponsored by:	Mellanox Technologies
Approved by:	re, glebius
MFC r272253:

Regenerate usb.conf

Approved by:    re, gjb
MFC r272254:
Instead of creating the full range of possible ports, try to figure
out the actual number of so-called "embedded jacks" which are present
when a USB MIDI device is attaching.

Approved by: re, gjb
MFC r272274:
Change the /var dataset in the default ZFS layout to have the
ZFS property canmount=off, making /var/db/pkg part of the / dataset, so
installed package files are consistent with the package database when
using ZFS boot environments (beadm).

PR:		193971
Reviewed by:	Shawn Webb, bcr
Approved by:	re (gjb), jmg
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
MFC r272389:

Diff reduction with kernel code: instruct the compiler that the data of
these types may be unaligned to their "normal" alignment and exercise
caution when accessing them.

PR:		194071
Approved by:	re (gjb)
MFC r270183:

  Avoid showing stale errors when nmount(2) fails.

  This should not be documented in relnotes as it still fails due to a
  race with unmounting, but no longer shows bogus details.

Approved by:	re (gjb)
MFC r271321:

  Don't cross mount boundaries when cleaning tmp files.

Approved by:	re (gjb)
Relnotes:	yes
MFC r272028:

  Make it more explicitly clear that -t will not change filename.

Approved by:	re (gjb)
MFC r271720:

  If fgets(3) fails in getbounds(), show strerror(3) if not an EOF. Also fix a
  FILE* leak in getbounds().

PR:		192032
Approved by:	re (gjb)
MFC r272288,272289:

When setting environment variables in the atrun script, use the
"export foo=bar" form instead of "foo=bar; export foo" since the
former allows the shell to catch variable names that are not valid
shell identifiers.  This will cause /bin/sh to exit with an error
(which gets mailed to the at user) and it will not run the script.

Obtained from:	OpenBSD (r1.63 millert)
Approved by:	re (gjb)
MFC r271141: Allow multiple image activators to run on the same
execution by changing imgp->interpreted to a bitmask instead of,
functionally, a bool.

Approved by:	re (gjb)
MFC r271527: MFV r271511:

Use fnvlist_* to make code more readable.

Illumos issue:
    5135 zpool_find_import_cached() can use fnvlist_*

Approved by:	re (gjb)
MFC r271528: MFV r271512:

Illumos issue:
    5136 fix write throttle comment in dsl_pool.c

Approved by:	re (gjb)
Update stable/10 to -RC1 in preparation of branching releng/10.1

Approved by:	re (implicit)
Sponsored by:	The FreeBSD Foundation
Bump __FreeBSD_version after releng/10.1 branch.

Approved by:	re (implicit)
Sponsored by:	The FreeBSD Foundation
MFC 271759:

Add missing links to taskqueue(9).

Sponsored by:	The FreeBSD Foundation
MFC 271761:

Add missing link to TIMEOUT_TASK_INIT(9).

Sponsored by:	The FreeBSD Foundation
MFC	r271467, r271468:
ext2fs: add ext2_getpages().

Literally copy/pasted from ffs_getpages().

Tested with:	fsx
MFC r271747:
 - Use NULL instead of 0 for fpcurthread.
 - Note the quirk with the interrupt enabled state of the dna handler.
 - Use just panic() instead of printf() and panic().  Print tid instead
   of pid, the fpu state is per-thread.

MFC r271924:
Update and clarify comments.  Remove the useless counter for impossible, but
seen in wild situation (on buggy hypervisors).