Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

LinuxKPI list updates:
- Add some new hlist macros.
- Update existing hlist macros removing the need for a temporary
iteration variable.
- Properly define the RCU hlist macros to be SMP safe with regard
to RCU.
- Safe list macro arguments by adding a pair of parentheses.
- Prefix the _list_add() and _list_splice() functions with "linux"
to reflect they are LinuxKPI internal functions.

Obtained from: Linux
MFC after: 1 week
Sponsored by: Mellanox Technologies

Implement RCU mechanism using shared exclusive locks.

MFC after: 1 week
Sponsored by: Mellanox Technologies