[PATCH 0/5][Bionic][SRU Artful] Switch arm64 over to qrwlock

[dann frazier]

BugLink: http://bugs.launchpad.net/bugs/1732238

These patches comprise all clean cherry picks that landed in the 4.15
merge window. Verified on a ThunderX2-based Sabre board, and regression
tested on a 128-cpu x86 system using stress-ng and locktorture. (The other
Ubuntu architectures don't use qrwlocks).

Will Deacon (5):
  locking/qrwlock: Use 'struct qrwlock' instead of 'struct __qrwlock'
  locking/atomic: Add atomic_cond_read_acquire()
  locking/qrwlock: Use atomic_cond_read_acquire() when spinning in
    qrwlock
  locking/qrwlock, arm64: Move rwlock implementation over to qrwlocks
  locking/qrwlock: Prevent slowpath writers getting held up by fastpath

 arch/arm64/Kconfig                      |  17 ++++
 arch/arm64/include/asm/Kbuild           |   1 +
 arch/arm64/include/asm/spinlock.h       | 164 +-------------------------------
 arch/arm64/include/asm/spinlock_types.h |   6 +-
 include/asm-generic/atomic-long.h       |   3 +
 include/asm-generic/qrwlock.h           |  37 ++-----
 include/asm-generic/qrwlock_types.h     |  15 ++-
 include/linux/atomic.h                  |   4 +
 kernel/locking/qrwlock.c                |  86 +++--------------
 9 files changed, 61 insertions(+), 272 deletions(-)

-- 
2.15.1