Document r260177, camcontrol '-b' addition.

Sponsored by:	The FreeBSD Foundation
Document r260338

Sponsored by:	The FreeBSD Foundation
Document r260385, unmapped I/O in GEOM RAID.

Sponsored by:	The FreeBSD Foundation
Fix order by svn revision.

Sponsored by:	The FreeBSD Foundation
Document r260431, kern.panic_reboot_wait_time sysctl.

Sponsored by:	The FreeBSD Foundation
MFC r264243:

Loosen the processing of *_IF_aliasN vars to be less strict. Previously,
the first alias had to be _alias0 and processing stopped at the first non-
defined variable (preventing gaps). Allowing gaps gives the administrator
the ability to group aliases in an adhoc manner and also lifts the
requirement to renumber aliases simply to comment-out an existing one.
Aliases are processed in numerical ascending order.

NB: Also Patches mdconfig{,2} rc(8) boot scripts to loosen the numbering
scheme for mdconfig_mdN settings to be less strict in the same manner.

Discussed on:	-rc
MFC r264343:
  Add SRC_UPDATE_SKIP, DOC_UPDATE_SKIP, and PORTS_UPDATE_SKIP
  variables.  These are intended to allow bypassing the
  'svn co /usr/{src,doc,ports}' step in the chroot when the
  tree exists from external means.

  The use case here is that /usr/src, /usr/doc, and /usr/ports
  in the chroot exist as result of zfs dataset clones, so it
  is possible (and happens quite often) that the included
  distributions may not be consistent.  (This is not the case
  for -RELEASE builds, but does happen for snapshot builds.)

Sponsored by:	The FreeBSD Foundation
MFC r263957:
  Increase the number of TX DMA segments from 32 to 35.  It turned
  out 32 is not enough to support a full sized TSO packet.
  While I'm here fix a long standing bug introduced in r169632 in
  bce(4) where it didn't include L2 header length of TSO packet in
  the maximum DMA segment size calculation.
MFC r259543:
  Failed m_devget(9) indicates lack of free mbuf cluster.  Update
  if_iqdrops counter for that case since the received frame is ok.
  While here, simplify updating counter logic.
MFC r260429:
  m_defrag(9) does not touch original mbuf chain when it can't
  allocate new mbuf.  Free original mbuf chain when driver is not
  able to send the packet.
MFC r264448: Fix typo in debug/log statement.

Submitted by:	Rick Miller <vmiller@hostileadmin.com>
MFC r264220:
Execute pf_overload_task() in vnet context. Fixes a vnet kernel panic.

Reviewed by:	trociny