Go back to direct-dispatch of the software queue and frame TX paths
when they're being called from the TX completion handler.

Going (back) through the taskqueue is just adding extra locking and
latency to packet operations.  This improves performance a little bit
on most NICs.

It still hasn't restored the original performance of the AR5416 NIC
but the AR9160, AR9280 and later NICs behave very well with this.

Tested:

* AR5416 STA (still tops out at ~ 70mbit TCP, rather than 150mbit TCP..)
* AR9160 hostap (good for both TX and RX)
* AR9280 hostap (good for both TX and RX)
MFV r246390:
Import minor type change in refcount.h header from vendor (illumos).

MFC after:	2 weeks
Put this back into the ath taskqueue rather than the ath TX taskqueue.

This now should mean all the entry points into the software TX
scheduler are back in the same taskqueue.
Update vendor-sys/illumos/dist to illumos-gate 13952:7a22d0770fc8

Illumos ZFS issues:
  3522 zfs module should not allow uninitialized variables
Update vendor/illumos/dist and vendor-sys/illumos/dist
to illumos-gate 13953:0cc6917308f7

Illumos dtrace issues:
  3529 iostat should display time used by dtrace
Use DEVMETHOD_END.
Add -lheimntlm to LDADD directly.

With the current binutils, symbols from libheimtlm.so are loaded because
it is referenced by DT_NEEDED.  This feature is not implemented in
mclinker (https://code.google.com/p/mclinker/issues/detail?id=104).
I encountered the same issue when linking with a recent devel/binutils
invoked via clang.  This was the only use of DT_NEEDED in the tree so
removing it simplifies toolchain requirements.

Submitted by:	Pete Chou <petechou@gmail.com> (mclinker issue)
Cross-reference vfs_unbusy(9).

MFC after:	1 week
  Resolve source address selection in presense of CARP. Add a couple
of helper functions:

- carp_master()   - boolean function which is true if an address
		    is in the MASTER state.
- ifa_preferred() - boolean function that compares two addresses,
		    and is aware of CARP.

  Utilize ifa_preferred() in ifa_ifwithnet().

  The previous version of patch also changed source address selection
logic in jails using carp_master(), but we failed to negotiate this part
with Bjoern. May be we will approach this problem again later.

Reported & tested by:	Anton Yuzhaninov <citrin citrin.ru>
Sponsored by:		Nginx, Inc
Add watchdog driver for Allwinner A10
A10 reset mechanism is the same for all boards in this family so remove
redundant reset function implementation pointer. We might want to
ressurect it later when support for other Allwinner chips is introduced.
MFV r246392:
Import vendor ZFS bugfix fixing a possible deadlock in arc_read().

Illumos ZFS issues:
  3498 panic in arc_read(): !refcount_is_zero(&pbuf->b_hdr->b_refcnt)

References:
  https://www.illumos.org/issues/3498

MFC after:	2 weeks
Major update for unix_cmsg from Andrey Simonenko.

Quoting the submitter:
- Added tests for SCM_BINTIME, LOCAL_PEERCRED, cmsghdr.cmsg_len
- Code that checks correctness of groups was corrected (getgroups(2) change)
- unix_cmsg.c was completely redesigned and simplified
- Use less timeout value in unix_cmsg.c for faster work
- Added support for not sending data in a message, not sending data and
  data array associated with a cmsghdr structure in a message
- Existent tests were improved
- unix_cmsg.t was redesigned and simplified

Correctness of unix_cmsg verified on 7.1-STABLE, 9.1-STABLE and 10-CURRENT.

PR:		bin/131567
Submitted by:	Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
MFC after:	2 weeks
Don't send kernel provided information in the User Initiated
ABORT cause, since the user can also provide this kind of
information. So the receiver doesn't know who provided the
information.
While there: Fix a bug where the stack would send a malformed
ABORT chunk when using a send() call with SCTP_ABORT|SCT_SENDALL
flags.

MFC after: 3 days
MFV r246394:
Add tunable to allow block allocation on degraded vdevs.

Illumos ZFS issues:
  3507 Tunable to allow block allocation even on degraded vdevs

References:
  https://www.illumos.org/issues/3507

MFC after:	2 weeks
MFV r246633:
Import vendor bugfixes regarding SA rounding, header size and layout.
This was already partially fixed by avg.

Illumos ZFS issues:
  3512 rounding discrepancy in sa_find_sizes()
  3513 mismatch between SA header size and layout

References:
  https://www.illumos.org/issues/3512
  https://www.illumos.org/issues/3513

MFC after:	2 weeks
Use the right year.

Noticed by:	Denis Ahrens <denis h3q com>
Implement guest vcpu pinning using 'pthread_setaffinity_np(3)'.

Prior to this change pinning was implemented via an ioctl (VM_SET_PINNING)
that called 'sched_bind()' on behalf of the user thread.

The ULE implementation of 'sched_bind()' bumps up 'td_pinned' which in turn
runs afoul of the assertion '(td_pinned == 0)' in userret().

Using the cpuset affinity to implement pinning of the vcpu threads works with
both 4BSD and ULE schedulers and has the happy side-effect of getting rid
of a bunch of code in vmm.ko.

Discussed with:	grehan
Send the adaptation layer indication only if set by the user.

MFC after: 3 days
Discussed with: rrs
Merge zfs_ioctl.c code that should have been merged together with ZFS v28.
Fixes several problems if working with read-only pools.

Changed code originaly introduced in onnv-gate 13061:bda0decf867b
Contains changes up to illumos-gate 13700:4bc0783f6064

PR:		kern/175897
Suggested by:	avg

MFC after:	2 weeks