MFC r263460:
Take filedesc lock only for reading when allocating new fdtable.

Code populating the table does this already.
MFC r263530:
Mark the following sysctls as MPSAFE:
kern.file
kern.proc.filedesc
kern.proc.ofiledesc
MFC r263458:
audit: plug FILEDESC_LOCK leak in audit_canon_path.
MFC r263704:
Make /dev/devctl mpsafe.

MFC r263753:
Remove lockless check in devopen, while correct it does not make much sense.
MFC r263755:
Document a known problem with handling the process intended to receive
SIGIO in /dev/devctl.
MFC r263758:
Update userspace users of hw.bus.devctl_disable.

This switches the code to use hw.bus.devctl_queue instead.
MFC r263468:
  When loader(8) inspects MBR, it chooses GPT as main partition table,
  when MBR contains only PMBR entry or it is bootcamp-compatible.
  If MBR has PMBR entry and some other, the loader rejects it.

  Make these checks to be less strict. If loader decided that PMBR
  isn't suitable for GPT, it will use MBR.

  Reported by:	Paul Thornton
MFC r263271

share/man/man9/counter.9
	Fix logic error in the description of counter_u64_alloc: the command
	may fail only if M_NOWAIT is specified, not M_WAITOK.
MFC revisions 260894,260899,262895-262902,262904,262908-262910,262982,
262984,263133-263137,263139,263141,263144-263150, and (partially) 263249
(31 revisions; summarized below)...
r260894: Optimize f_expand_number(), improving performance
r260899: s/__number/__num/ in f_expand_number()
r262895: Allow dispatched reswords to carry arguments
r262896: Add missing local declaration
r262897: Fix a typo in a comment
r262898: Fix incorrect return status if var_to_set and var_to_get are same
r262899: Make f_show_err non-fatal
r262900: Centralize function name; Update a comment while here
r262901: s/__num/__number/ in f_expand_number()
r262902: Comment to go with NL global introduced by previous commit
r262904: Rewrite groupmgmt -- hooking it into the scripting system
r262908: Change dispatch words from group* to *Group for backward compat
r262909: Fix copy/paste error in a comment
r262910: Take a group name on the command-line if available
r262982: Whitespace
r262984: Remove vestigial global, no longer used since r262904
r263133: Remove indexfile from debug statement (already logged)
r263134: Add debug statement just before attempting to exec a module
r263135: Comments
r263136: Update copyright
r263137: Fix future namespace issues for functions taking $var_to_set
r263139: Remove useless NULL string in compound strings
r263141: Pointy hat! Fix a broken f_isinteger()
r263144: Fix a code-typo that prevented auto-sizing of a dialog
r263145: Fix comments and whitespace
r263146: Reduce the sleep cycle when using dialog(1) [infobox] to 1-second
r263147: Fix a bug preventing errors from pw(8) from appearing
r263148: For non-interactive scripts, forgot to check argument
r263149: Add protection against input containing single-quotes
r263150: Rewrite usermgmt
r263249: (partial) Add more obsolete files
MFC r263891:

Make clang default to DWARF2 debug info format for FreeBSD 10.x and
earlier.  For head, this commit does not change anything, but it is
purely meant to be MFC'd.
MFC r263118:
Report ZVOL block size as GEOM stripesize.
MFC r263775:

Avoid "cc1: warning: is shorter than expected" when using GNU cpp in
combination with dtrace scripts, which have "#!/usr/sbin/dtrace -Cs"
shebang lines.  This is because dtrace positions the file pointer after
the shebang line, before passing the file to GNU cpp.

To fix the warning, adjust the size downwards by the current position,
after a bit of sanity checking.

Suggested by:	avg
MFC r263385:

Remove unused option -r from zpool.

Submitted by:	Richard Yao <ryao gentoo org>
MFC r263809

Fix crash on resume in vt(9).
Statically allocated terminal window have not initialized callout handler, so we
have to initialize it even for existing window if it is console window.

Sponsored by:	The FreeBSD Foundation
Document that the FreeBSD/i386 instability with
vfs.unmapped_buf_allowed=1 may be present on VMs
running on hypervisors other than VirtualBox.

Sponsored by:	The FreeBSD Foundation
MFC r263812:

  Update build(7) with LOCAL_* vars
o Provide a compatibility shim for netstat(1) to obtain output queue
  drops via NET_RT_IFLISTL sysctl. The sysctl handler appends oqdrops
  at the end of struct if_msghdrl, and netstat(1) sees that as an
  additional field of struct if_data. This allows us to fetch the data
  keeping ABI and API compatibility.
  This is direct commit to stable/10.

o Merge r263331 from head, to restore printing of queue drops.

Sponsored by:	Nginx, Inc.
Sponsored by:	Netflix
MFC r263116

Replace 4.4BSD Lite's unix domain socket backpressure hack with a cleaner
mechanism, based on the new SB_STOP sockbuf flag.  The old hack dynamically
changed the sending sockbuf's high water mark whenever adding or removing
data from the receiving sockbuf.  It worked for stream sockets, but it never
worked for SOCK_SEQPACKET sockets because of their atomic nature.  If the
sockbuf was partially full, it might return EMSGSIZE instead of blocking.

The new solution is based on DragonFlyBSD's fix from commit
3a6117bbe0ed6a87605c1e43e12a1438d8844380 on 2008-05-27.  It adds an SB_STOP
flag to sockbufs.  Whenever uipc_send surpasses the socket's size limit, it
sets SB_STOP on the sending sockbuf.  sbspace() will then return 0 for that
sockbuf, causing sosend_generic and friends to block.  uipc_rcvd will
likewise clear SB_STOP.  There are two fringe benefits: uipc_{send,rcvd} no
longer need to call chgsbsize() on every send and receive because they don't
change the sockbuf's high water mark.  Also, uipc_sense no longer needs to
acquire the UIPC linkage lock, because it's simpler to compute the
st_blksizes.

There is one drawback: since sbspace() will only ever return 0 or the
maximum, sosend_generic will allow the sockbuf to exceed its nominal maximum
size by at most one packet of size less than the max.  I don't think that's
a serious problem.  In fact, I'm not even positive that FreeBSD guarantees a
socket will always stay within its nominal size limit.

sys/sys/sockbuf.h
	Add the SB_STOP flag and adjust sbspace()

sys/sys/unpcb.h
	Delete the obsolete unp_cc and unp_mbcnt fields from struct unpcb.

sys/kern/uipc_usrreq.c
	Adjust uipc_rcvd, uipc_send, and uipc_sense to use the SB_STOP
	backpressure mechanism.  Removing obsolete unpcb fields from
	db_show_unpcb.

tests/sys/kern/unix_seqpacket_test.c
	Clear expected failures from ATF.
MFC r263428

share/man/man7/tests.7
	Added a section on test suite configuration, and cleaned up up grammar
	errors and awkward prose.  The config variables were discussed on
	freebsd-testing.
MFC r262810, r262862, r264105:
r262810:
  Merge enabling building FreeBSD/arm images as part of the
  release build process.

r262862:
  Provide backwards-compatibility with release.conf SVNROOT
  entries that do not have a trailing '/'.

r264105:
  Add ZEDBOARD support for release builds.

* Local modifications:
  - Set SRCBRANCH from head/ to stable/10/.
  - Strip svn:merginfo from ^/projects/release-embedded to avoid
    pollution.

Sponsored by:	The FreeBSD Foundation