1 files changed, 17 insertions, 36 deletions

diff --git a/include/asm-generic/qspinlock.h b/include/asm-generic/qspinlock.h
index 6bd05700d8c9..05f05f17a7c2 100644
--- a/include/asm-generic/qspinlock.h
+++ b/include/asm-generic/qspinlock.h
@@ -22,37 +22,33 @@
 #include <asm-generic/qspinlock_types.h>
 
 /**
+ * queued_spin_unlock_wait - wait until the _current_ lock holder releases the lock
+ * @lock : Pointer to queued spinlock structure
+ *
+ * There is a very slight possibility of live-lock if the lockers keep coming
+ * and the waiter is just unfortunate enough to not see any unlock state.
+ */
+#ifndef queued_spin_unlock_wait
+extern void queued_spin_unlock_wait(struct qspinlock *lock);
+#endif
+
+/**
  * queued_spin_is_locked - is the spinlock locked?
  * @lock: Pointer to queued spinlock structure
  * Return: 1 if it is locked, 0 otherwise
  */
+#ifndef queued_spin_is_locked
 static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
 {
         /*
-         * queued_spin_lock_slowpath() can ACQUIRE the lock before
-         * issuing the unordered store that sets _Q_LOCKED_VAL.
-         *
-         * See both smp_cond_acquire() sites for more detail.
-         *
-         * This however means that in code like:
-         *
-         *   spin_lock(A)               spin_lock(B)
-         *   spin_unlock_wait(B)        spin_is_locked(A)
-         *   do_something()             do_something()
-         *
-         * Both CPUs can end up running do_something() because the store
-         * setting _Q_LOCKED_VAL will pass through the loads in
-         * spin_unlock_wait() and/or spin_is_locked().
+         * See queued_spin_unlock_wait().
          *
-         * Avoid this by issuing a full memory barrier between the spin_lock()
-         * and the loads in spin_unlock_wait() and spin_is_locked().
-         *
-         * Note that regular mutual exclusion doesn't care about this
-         * delayed store.
+         * Any !0 state indicates it is locked, even if _Q_LOCKED_VAL
+         * isn't immediately observable.
          */
-        smp_mb();
-        return atomic_read(&lock->val) & _Q_LOCKED_MASK;
+        return atomic_read(&lock->val);
 }
+#endif
 
 /**
  * queued_spin_value_unlocked - is the spinlock structure unlocked?
@@ -122,21 +118,6 @@ static __always_inline void queued_spin_unlock(struct qspinlock *lock)
 }
 #endif
 
-/**
- * queued_spin_unlock_wait - wait until current lock holder releases the lock
- * @lock : Pointer to queued spinlock structure
- *
- * There is a very slight possibility of live-lock if the lockers keep coming
- * and the waiter is just unfortunate enough to not see any unlock state.
- */
-static inline void queued_spin_unlock_wait(struct qspinlock *lock)
-{
-        /* See queued_spin_is_locked() */
-        smp_mb();
-        while (atomic_read(&lock->val) & _Q_LOCKED_MASK)
-                cpu_relax();
-}
-
 #ifndef virt_spin_lock
 static __always_inline bool virt_spin_lock(struct qspinlock *lock)
 {