Merge from vmc-playground branch:
Replace the sub-optimal uma_zone_set_obj() primitive with more modern
uma_zone_reserve_kva().  The new primitive reserves before hand
the necessary KVA space to cater the zone allocations and allocates pages
with ALLOC_NOOBJ.  More specifically:
- uma_zone_reserve_kva() does not need an object to cater the backend
  allocator.
- uma_zone_reserve_kva() can cater M_WAITOK requests, in order to
  serve zones which need to do uma_prealloc() too.
- When possible, uma_zone_reserve_kva() uses directly the direct-mapping
  by uma_small_alloc() rather than relying on the KVA / offset
  combination.

The removal of the object attribute allows 2 further changes:
1) _vm_object_allocate() becomes static within vm_object.c
2) VM_OBJECT_LOCK_INIT() is removed.  This function is replaced by
   direct calls to mtx_init() as there is no need to export it anymore
   and the calls aren't either homogeneous anymore: there are now small
   differences between arguments passed to mtx_init().

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc (which also offered almost all the comments)
Tested by:	pho, jhb, davide
Add in the STBC TX/RX capability support into the HAL and driver.

The HAL already included the STBC fields; it just needed to be exposed
to the driver and net80211 stack.

This should allow single-stream STBC TX and RX to be negotiated; however
the driver and rate control code currently don't do anything with it.
Fixes mfi panic on recused on non-recusive mutex MFI I/O lock

Removes a mtx_unlock call for mfi_io_lock which is never aquired

While I'm here fix a braceing style issue.

Reviewed by:	Doug Ambrisko
Approved by:	pjd (mentor)
MFC after:	1 month
Enable STBC for the given rate series if it's negotiated:

* If both ends have negotiated (at least) one stream;
* Only if it's a single stream rate (MCS0-7);
* Only if there's more than one TX chain enabled.

Tested:

* AR9280 STA mode -> Atheros AP; tested both MCS2 (STBC) and MCS12 (no STBC.)
  Verified using athalq to inspect the TX descriptors.

TODO:

* Test AR5416 - no STBC should be enabled;
* Test AR9280 with one TX chain enabled - no STBC should be enabled.
Fixes queuing issues where mfi_release_command blindly sets the cm_flags = 0
without first removing the command from the relavent queue.

This was causing panics in the queue functions which check to ensure a command
is not on another queue.

Fixed some cases where the error from mfi_mapcmd was lost and where the command
was never released / dequeued in error cases.

Ensure that all failures to mfi_mapcmd are logged.

Fixed possible null pointer exception in mfi_aen_setup if mfi_get_log_state
failed.

Fixed mfi_parse_entries & mfi_aen_setup not returning possible errors.

Corrected MFI_DUMP_CMDS calls with invalid vars SC vs sc.

Commands which have timed out now set cm_error to ETIMEDOUT and call
mfi_complete which prevents them getting stuck in the busy queue forever.

Fixed possible use of NULL pointer in mfi_tbolt_get_cmd.

Changed output formats to be more easily recognisable when debugging.

Optimised mfi_cmd_pool_tbolt cleanup.

Made information about driver limiting commands always display as for modern
cards this can be severe.

Fixed mfi_tbolt_alloc_cmd out of memory case which previously didnt return an
error.

Added malloc checks for request_desc_pool including free when subsiquent errors
are detected.

Fixed overflow error in SIMD reply descriptor check.

Fixed tbolt_cmd leak in mfi_build_and_issue_cmd if there's an error during IO
build.

Elimintated double checks on sc->mfi_aen_cm & sc->mfi_map_sync_cm in
mfi_shutdown.

Move local hdr calculation after error check in mfi_aen_complete.

Fixed wakeup on NULL in mfi_aen_complete.

Fixed mfi_aen_cm cleanup in mfi_process_fw_state_chg_isr not checking if it was
NULL.

Changed mfi_alloc_commands to error if bus_dmamap_create fails. Previously we
would try to continue with the number of allocated commands but lots of places
in the driver assume sc->mfi_max_fw_cmds is whats available so its unsafe to do
this without lots of changes.

Removed mfi_total_cmds as its no longer used due the above change.

Corrected mfi_tbolt_alloc_cmd to return ENOMEM where appropriate.

Fixed timeouts actually firing at double what they should.

Setting hw.mfi.max_cmds=-1 now configures to use the controller max.

A few style (9) fixes e.g. braced single line conditions and double blank lines

Cleaned up queuing macros

Removed invalid queuing tests for multiple queues

Trap and deal with errors when doing sends in mfi_data_cb

Refactored frame sending into one method with error checking of the return
code so we can ensure commands aren't left on the queue after error. This
ensures that mfi_mapcmd & mfi_data_cb leave the queue in a valid state.

Refactored how commands are cleaned up, mfi_release_command now ensures
that all queues and command state is maintained in a consistent state.

Prevent NULL pointer use in mfi_tbolt_complete_cmd

Fixed use of NULL sc->mfi_map_sync_cm in wakeup

Added defines to help with output of mfi_cmd and header flags.

Fixed mfi_tbolt_init_MFI_queue invalidating cm_index of the acquired mfi_cmd.

Reset now reinitialises sync map as well as AEN.

Fixed possible use of NULL pointer in mfi_build_and_issue_cmd

Fixed mfi_tbolt_init_MFI_queue call to mfi_process_fw_state_chg_isr causing
panic on failure.

Ensure that tbolt cards always initialise next_host_reply_index and
free_host_reply_index (based off mfi_max_fw_cmds) on both startup and
reset as per the linux driver.

Fixed mfi_tbolt_complete_cmd not acknowledging unknown commands so
it didn't clear the controller.

Prevent locks from being dropped and re-acquired in the following functions
which was allowing multiple threads to enter critical methods such as
mfi_tbolt_complete_cmd & mfi_process_fw_state_chg_isr:-
* mfi_tbolt_init_MFI_queue
* mfi_aen_complete / mfi_aen_register
* mfi_tbolt_sync_map_info
* mfi_get_log_state
* mfi_parse_entries

The locking for these functions was promoting to higher level methods. This
also fixed MFI_LINUX_SET_AEN_2 which was already acquiring the lock, so would
have paniced for recursive lock.

This also required changing malloc of ld_sync in mfi_tbolt_sync_map_info to
M_NOWAIT which can hence now fail but this was already expected as its return
was being tested.

Removed the assignment of cm_index in mfi_tbolt_init_MFI_queue which breaks
the world if the cmd returned by mfi_dequeue_free isn't the first cmd.

Fixed locking in mfi_data_cb, this is an async callback from bus_dmamap_load
which could hence be called after the caller has dropped the lock. If we
don't have the lock we aquire it and ensure we unlock before returning.

Fixed locking mfi_comms_init when mfi_dequeue_free fails.

Fixed mfi_build_and_issue_cmd not returning tbolt cmds aquired to the pool
on error.

Fixed mfi_abort not dropping the io lock when mfi_dequeue_free fails.

Added hw.mfi.polled_cmd_timeout sysctl that enables tuning of polled
timeouts. This shouldn't be reduced below 50 seconds as its used for
firmware patching which can take quite some time.

Added hw.mfi.fw_reset_test sysctl which is avaliable when compiled with
MFI_DEBUG and allows the testing of controller reset that was provoking a
large number of the issues encountered here.

Reviewed by:	Doug Ambrisko
Approved by:	pjd (mentor)
MFC after:	1 month
Fix typo in EFI GPT GUID.
I give up - just throw the EWMA update into the normal update_stats()
routine.

There were still corner cases where the EWMA update stats are being
called on a rix which didn't have an intermediary stats update; thus
no packets were counted against it.  Sigh.

This should fix the crashes I've been seeing on recent -HEAD.
RX checksum offloading on old Yukon controllers seem to cause more
problems.  Disable RX checksum offloading on controllers that don't
use new descriptor format but give chance to enable it with
ifconfig(8).
Clear the memory allocated to build the unwind tables. This fixes C++
exceptions on ARM EABI with static binaries.
An inode block must not be blockingly read while cg block is owned.
The order is inode buffer lock -> snaplk -> cg buffer lock, reversing
the order causes deadlocks.

Inode block must not be written while cg block buffer is owned. The
FFS copy on write needs to allocate a block to copy the content of the
inode block, and the cylinder group selected for the allocation might
be the same as the owned cg block.  The reserved block detection code
in the ffs_copyonwrite() and ffs_bp_snapblk() is unable to detect the
situation, because the locked cg buffer is not exposed to it.

In order to maintain the dependency between initialized inode block
and the cg_initediblk pointer, look up the inode buffer in
non-blocking mode. If succeeded, brelse cg block, initialize the inode
block and write it.  After the write is finished, reread cg block and
update the cg_initediblk.

If inode block is already locked by another thread, let the another
thread initialize it.  If another thread raced with us after we
started writing inode block, the situation is detected by an update of
cg_initediblk.  Note that double-initialization of the inode block is
harmless, the block cannot be used until cg_initediblk is incremented.

Sponsored by:	The FreeBSD Foundation
In collaboration with:	pho
Reviewed by:	mckusick
MFC after:	1 month
X-MFC-note:	after r246877
The softdep freeblks workitem might hold a reference on the dquot.
Current dqflush() panics when a dquot with with non-zero refcount is
encountered.  The situation is possible, because quotas are turned off
before softdep workitem queue if flushed, due to the quota file writes
might create softdep workitems.

Make the encountering an active dquot in dqflush() not fatal, return
the error from quotaoff() instead.  Ignore the quotaoff() failures
when ffs_flushfiles() is called in the course of softdep_flushfiles()
loop, until the last iteration.  At the last loop, the quotas must be
closed, and because SU workitems should be already flushed, the
references to dquot are gone.

Sponsored by:	The FreeBSD Foundation
Reported and tested by:	pho
Reviewed by:	mckusick
MFC after:	2 weeks
Make recursive getblk() slightly more useful.  Keep the buffer state
intact if getblk() is done on the already owned buffer.  Exit from
brelse() early when the lock recursion is detected, otherwise brelse()
might prematurely destroy the buffer under some circumstances.

Sponsored by:	The FreeBSD Foundation
Noted by:	mckusick
Tested by:	pho
MFC after:	2 weeks
- Initialize GPIO_OE register based on pinmux configuration

Although AM335x TRM states that GPIO_OE register is not used and just
reflects pads configuration in practice it does control pin behavior
and shoiuld be set in addition to pinmux setup
Fix typo
Map libraries linked with -Ttext-segment=base_addr at base_addr.
Normal libraries have base address 0 and are unaffected by this change.

PR:		176216
Submitted by:	Damjan Jovanovic <damjan.jov@gmail.com>
Reviewed by:	kib
MFC after:	1 week
MFV 247176, 247178, 247315:
Import metaslab_sync() speedup from vendor (illumos).

Illumos ZFS issues:
  3552 condensing one space map burns 3 seconds of CPU in spa_sync() thread
  3564 spa_sync() spends 5-10% of its time in metaslab_sync() (when not
       condensing)
  3578 transferring the freed map to the defer map should be constant time
  3579 ztest trips assertion in metaslab_weight()

References:
  https://www.illumos.org/issues/3552
  https://www.illumos.org/issues/3564
  https://www.illumos.org/issues/3578
  https://www.illumos.org/issues/3579

MFC after:	2 weeks
The .journal file needs to reside on the ROOTINO which must not extend
beyond direct blocks. A typo caused this check to fail.
Merge from vmobj-rwlock:
VM_OBJECT_LOCKED() macro is only used to implement a custom version
of lock assertions right now (which likely spread out thanks to
copy and paste).
Remove it and implement actual assertions.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc
Tested by:	pho
watchdogd(8) and watchdog(4) enhancements.

The following support was added to watchdog(4):
- Support to query the outstanding timeout.
- Support to set a software pre-timeout function watchdog with an 'action'
- Support to set a software only watchdog with a configurable 'action'

'action' can be a mask specifying a single operation or a combination of:
 log(9), printf(9), panic(9) and/or kdb_enter(9).

Support the following in watchdogged:
- Support to utilize the new additions to watchdog(4).
- Support to warn if a watchdog script runs for too long.
- Support for "dry run" where we do not actually arm the watchdog,
  but only report on our timing.

Sponsored by:   iXsystems, Inc.
MFC after:      1 month
Add an implementation of open_memstream() and open_wmemstream().  These
routines provide write-only stdio FILE objects that store their data in a
dynamically allocated buffer.  They are a string builder interface somewhat
akin to a completely dynamic sbuf.

Reviewed by:	bde, jilles (earlier versions)
MFC after:	1 month