Pull locking updates from Ingo Molnar:
 "The main changes in this cycle are:

   - big rtmutex and futex cleanup and robustification from Thomas
     Gleixner
   - mutex optimizations and refinements from Jason Low
   - arch_mutex_cpu_relax() removal and related cleanups
   - smaller lockdep tweaks"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  arch, locking: Ciao arch_mutex_cpu_relax()
  locking/lockdep: Only ask for /proc/lock_stat output when available
  locking/mutexes: Optimize mutex trylock slowpath
  locking/mutexes: Try to acquire mutex only if it is unlocked
  locking/mutexes: Delete the MUTEX_SHOW_NO_WAITER macro
  locking/mutexes: Correct documentation on mutex optimistic spinning
  rtmutex: Make the rtmutex tester depend on BROKEN
  futex: Simplify futex_lock_pi_atomic() and make it more robust
  futex: Split out the first waiter attachment from lookup_pi_state()
  futex: Split out the waiter check from lookup_pi_state()
  futex: Use futex_top_waiter() in lookup_pi_state()
  futex: Make unlock_pi more robust
  rtmutex: Avoid pointless requeueing in the deadlock detection chain walk
  rtmutex: Cleanup deadlock detector debug logic
  rtmutex: Confine deadlock logic to futex
  rtmutex: Simplify remove_waiter()
  rtmutex: Document pi chain walk
  rtmutex: Clarify the boost/deboost part
  rtmutex: No need to keep task ref for lock owner check
  rtmutex: Simplify and document try_to_take_rtmutex()
  ...