The bssid can change from underneath us, so take a reference before
we fiddle with it.
Refactor out the sendfile copyout in order to make vn_sendfile()
callable from the kernel.

Right now vn_sendfile() can't be called from anything other than
a syscall handler _and_ return the number of bytes queued.
This simply moves the copyout() to do_sendfile() so that any kernel
code can initiate vn_sendfile() outside of a syscall context.

Tested:

* tiny little sendfile program spitting things out a tcp socket

Sponsored by:	Netflix, Inc.
The Data Byte Count (DBC) field of a Physical Region Descriptor
Table is 22 bits, with the bit 31 being the interrupt-on-completion
bit.

OpenBSD and UEFI set this bit, resulting in large block i/o lengths
being sent to bhyve and coredumping the process. Fix by masking off
the relevant 22 bits when using the DBC field as a length.

Reviewed by:	Zhixiang Yu
Discussed with:	Tycho Nightingale (tycho.nightingale@pluribusnetworks.com)
MFC after:	10.0
Take care to handle the full 16 byte buffer in the get/put routines. Also,
skip the VTERM header once when receiving data from the hypervisor call when
we have a HVTERMPROT connection.

MFC after:	1 week
Also note to add xhci(4) to kernel configuration to utilize USB 3.0

Approved by:	markj
Mention axge(4)

Approved by:	kevlo
DragonFly 3.6.0 released.
Pull in r195558 from upstream clang trunk:

  Fix a SSE2 intrinsics typo

  Full discourse at:

   http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20131104/092514.html
   http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-November/068124.html

  Patch by Dimitry Andric and Alexey Dokuchaev!

Reported by:	danfe
MFC after:	3 days
Fix the compat32 sendfile() to be in line with my recent changes.

Reminded by:	kib
dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Reviewed by:	markj
MFC after:	3 weeks
sdt: add support for solaris/illumos style DTRACE_PROBE macros

The new macros are implemented in terms of SDT_PROBE_DEFINE and SDT_PROBE.
Probes defined in this way will appear under SDT provider named "sdt".
Parameter types are exposed via SDT_PROBE_ARGTYPE.
This is something that illumos does not have by default.

This kind of SDT probes is already present in ZFS code, so those probes
will now be available if KDTRACE_HOOKS options is enabled.

A potential future illumos compatibility enhancement is to encode a provider
name as a prefix in a probe name.

Reviewed by:	markj
MFC after:	3 weeks
X-MFC after:	r258622
Add a new debug section.
Add definitions for the microcode TLV flags entry (type 18.)

This isn't used anywhere just yet!

Obtained from:	Linux iwlwifi
opensolaris taskq: some cosmetic changes

- drop trailing whitespace
- remove redundant "extern" from function declarations
- remove unused macro

MFC after:	1 week
Mention that devd will kldload the driver when the device is connected.

Mention that the automatic mode switch from umass to u3g needed by some
devices does not work unless the driver is loaded before the device is
connected.

MFC after:	1 month
734 taskq_dispatch_prealloc() desired

943 zio_interrupt ends up calling taskq_dispatch with TQ_SLEEP
illumos/illumos-gate@5aeb94743e3be0c51e86f73096334611ae3a058e

Essentially FreeBSD taskqueues already operate in a mode that
was added to Illumos with taskq_dispatch_ent change.
We even exposed the superior FreeBSD interface as taskq_dispatch_safe.
Now we just rename taskq_dispatch_safe to taskq_dispatch_ent and
struct struct ostask to taskq_ent_t, so that code differences will be
minimal.

After this change sys/cddl/compat/opensolaris/sys/taskq.h header is no
longer needed.

Note that this commit is not an MFV because the upstream change was not
individually committed to the vendor area.

MFC after:	8 days
MFV r247578: 3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock is piping hot

illumos/illumos-gate@ec94d32216ed5705f5176582355cc311cf848e73

MFC after:	9 days
Sponsored by:	HybridCluster [merge]
MFV r255255: 4045 zfs write throttle & i/o scheduler performance work

illumos/illumos-gate@69962b5647e4a8b9b14998733b765925381b727e

Please note the following changes:
- zio_ioctl has lost its priority parameter and now TRIM is executed
  with 'now' priority
- some knobs are gone and some new knobs are added; not all of them are
  exposed as tunables / sysctls yet

MFC after:	10 days
Sponsored by:	HybridCluster [merge]
MFV r255256: 3954 metaslabs continue to load even after hitting zfs_mg_alloc_failure limit

4080 zpool clear fails to clear pool
4081 need zfs_mg_noalloc_threshold

illumos/illumos-gate@22e30981d82a0b6dc89253596ededafae8655e00

MFC after:	10 days
Sponsored by:	HybridCluster [merge]
MFV r258376: 3964 L2ARC should always compress metadata buffers

illumos/illumos-gate@e4be62a2b74a8f09bb669217a1a39eee069b13a1

MFC after:	10 days
Sponsored by:	HybridCluster [merge]