Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Thomas Gleixner:
 "Three patches to fix memory ordering issues on ALPHA and a comment to
  clarify the usage scope of a mutex internal function"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/xchg/alpha: Fix xchg() and cmpxchg() memory ordering bugs
  locking/xchg/alpha: Clean up barrier usage by using smp_mb() in place of __ASM__MB
  locking/xchg/alpha: Add unconditional memory barrier to cmpxchg()
  locking/mutex: Add comment to __mutex_owner() to deter usage