locking/mutexes: Introduce cancelable MCS lock for adaptive spinning

Since we want a task waiting for a mutex_lock() to go to sleep and
reschedule on need_resched() we must be able to abort the
mcs_spin_lock() around the adaptive spin.

Therefore implement a cancelable mcs lock.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: chegu_vinod@hp.com
Cc: paulmck@linux.vnet.ibm.com
Cc: Waiman.Long@hp.com
Cc: torvalds@linux-foundation.org
Cc: tglx@linutronix.de
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
Cc: davidlohr@hp.com
Cc: hpa@zytor.com
Cc: andi@firstfloor.org
Cc: aswin@hp.com
Cc: scott.norton@hp.com
Cc: Jason Low <jason.low2@hp.com>
Link: http://lkml.kernel.org/n/tip-62hcl5wxydmjzd182zhvk89m@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index c482e1d2cc49..11692dea18aa 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -46,7 +46,7 @@
  * - detects multi-task circular deadlocks and prints out all affected
  *   locks and tasks (and only those tasks)
  */
-struct mcs_spinlock;
+struct optimistic_spin_queue;
 struct mutex {
         /* 1: unlocked, 0: locked, negative: locked, possible waiters */
         atomic_t                count;
@@ -56,7 +56,7 @@ struct mutex {
         struct task_struct      *owner;
 #endif
 #ifdef CONFIG_MUTEX_SPIN_ON_OWNER
-        struct mcs_spinlock     *mcs_lock;      /* Spinner MCS lock */
+        struct optimistic_spin_queue    *osq;   /* Spinner MCS lock */
 #endif
 #ifdef CONFIG_DEBUG_MUTEXES
         const char              *name;