From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 31 Mar 2014 17:59:39 +0000 (-0700)
Subject: Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: v3.15-rc1~184
X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=462bf234a82ae1ae9d7628f59bc81022591e1348

Merge branch 'core-locking-for-linus' of git://git./linux/kernel/git/tip/tip

Pull core locking updates from Ingo Molnar:
 "The biggest change is the MCS spinlock generalization changes from Tim
  Chen, Peter Zijlstra, Jason Low et al.  There's also lockdep
  fixes/enhancements from Oleg Nesterov, in particular a false negative
  fix related to lockdep_set_novalidate_class() usage"

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  locking/mutex: Fix debug checks
  locking/mutexes: Add extra reschedule point
  locking/mutexes: Introduce cancelable MCS lock for adaptive spinning
  locking/mutexes: Unlock the mutex without the wait_lock
  locking/mutexes: Modify the way optimistic spinners are queued
  locking/mutexes: Return false if task need_resched() in mutex_can_spin_on_owner()
  locking: Move mcs_spinlock.h into kernel/locking/
  m68k: Skip futex_atomic_cmpxchg_inatomic() test
  futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test
  Revert "sched/wait: Suppress Sparse 'variable shadowing' warning"
  lockdep: Change lockdep_set_novalidate_class() to use _and_name
  lockdep: Change mark_held_locks() to check hlock->check instead of lockdep_no_validate
  lockdep: Don't create the wrong dependency on hlock->check == 0
  lockdep: Make held_lock->check and "int check" argument bool
  locking/mcs: Allow architecture specific asm files to be used for contended case
  locking/mcs: Order the header files in Kbuild of each architecture in alphabetical order
  sched/wait: Suppress Sparse 'variable shadowing' warning
  hung_task/Documentation: Fix hung_task_warnings description
  locking/mcs: Allow architectures to hook in to contended paths
  locking/mcs: Micro-optimize the MCS code, add extra comments
  ...
---

462bf234a82ae1ae9d7628f59bc81022591e1348
diff --cc arch/avr32/include/asm/Kbuild
index c7c64a63c29f,8b398ff96974..00a0f3ccd6eb
--- a/arch/avr32/include/asm/Kbuild
+++ b/arch/avr32/include/asm/Kbuild
@@@ -1,22 -1,22 +1,23 @@@
  
- generic-y	+= clkdev.h
- generic-y       += cputime.h
- generic-y       += delay.h
- generic-y       += device.h
- generic-y       += div64.h
- generic-y       += emergency-restart.h
- generic-y	+= exec.h
- generic-y       += futex.h
- generic-y	+= preempt.h
- generic-y       += irq_regs.h
- generic-y	+= param.h
- generic-y       += local.h
- generic-y       += local64.h
- generic-y       += percpu.h
- generic-y       += scatterlist.h
- generic-y       += sections.h
- generic-y       += topology.h
- generic-y	+= trace_clock.h
+ generic-y += clkdev.h
+ generic-y += cputime.h
+ generic-y += delay.h
+ generic-y += device.h
+ generic-y += div64.h
+ generic-y += emergency-restart.h
+ generic-y += exec.h
+ generic-y += futex.h
+ generic-y += hash.h
+ generic-y += irq_regs.h
+ generic-y += local.h
+ generic-y += local64.h
+ generic-y += mcs_spinlock.h
+ generic-y += param.h
+ generic-y += percpu.h
+ generic-y += preempt.h
+ generic-y += scatterlist.h
+ generic-y += sections.h
+ generic-y += topology.h
+ generic-y += trace_clock.h
 +generic-y += vga.h
- generic-y       += xor.h
- generic-y	+= hash.h
+ generic-y += xor.h
diff --cc kernel/futex.c
index 08ec814ad9d2,5d17e3a83f8c..67dacaf93e56
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@@ -2893,21 -2882,10 +2914,11 @@@ static int __init futex_init(void
  					       &futex_shift, NULL,
  					       futex_hashsize, futex_hashsize);
  	futex_hashsize = 1UL << futex_shift;
- 	/*
- 	 * This will fail and we want it. Some arch implementations do
- 	 * runtime detection of the futex_atomic_cmpxchg_inatomic()
- 	 * functionality. We want to know that before we call in any
- 	 * of the complex code paths. Also we want to prevent
- 	 * registration of robust lists in that case. NULL is
- 	 * guaranteed to fault and we get -EFAULT on functional
- 	 * implementation, the non-functional ones will return
- 	 * -ENOSYS.
- 	 */
- 	if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT)
- 		futex_cmpxchg_enabled = 1;
+ 
+ 	futex_detect_cmpxchg();
  
  	for (i = 0; i < futex_hashsize; i++) {
 +		atomic_set(&futex_queues[i].waiters, 0);
  		plist_head_init(&futex_queues[i].chain);
  		spin_lock_init(&futex_queues[i].lock);
  	}