Generic semaphore implementation

Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 84 deletions

diff --git a/include/asm-arm/semaphore-helper.h b/include/asm-arm/semaphore-helper.h
deleted file mode 100644
index 1d7f1987edb..00000000000
--- a/include/asm-arm/semaphore-helper.h
+++ /dev/null
@@ -1,84 +0,0 @@
-#ifndef ASMARM_SEMAPHORE_HELPER_H
-#define ASMARM_SEMAPHORE_HELPER_H
-
-/*
- * These two _must_ execute atomically wrt each other.
- */
-static inline void wake_one_more(struct semaphore * sem)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (atomic_read(&sem->count) <= 0)
-		sem->waking++;
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-}
-
-static inline int waking_non_zero(struct semaphore *sem)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (sem->waking > 0) {
-		sem->waking--;
-		ret = 1;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-/*
- * waking non zero interruptible
- *	1	got the lock
- *	0	go to sleep
- *	-EINTR	interrupted
- *
- * We must undo the sem->count down_interruptible() increment while we are
- * protected by the spinlock in order to make this atomic_inc() with the
- * atomic_read() in wake_one_more(), otherwise we can race. -arca
- */
-static inline int waking_non_zero_interruptible(struct semaphore *sem,
-						struct task_struct *tsk)
-{
-	unsigned long flags;
-	int ret = 0;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (sem->waking > 0) {
-		sem->waking--;
-		ret = 1;
-	} else if (signal_pending(tsk)) {
-		atomic_inc(&sem->count);
-		ret = -EINTR;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;	
-}
-
-/*
- * waking_non_zero_try_lock:
- *	1	failed to lock
- *	0	got the lock
- *
- * We must undo the sem->count down_interruptible() increment while we are
- * protected by the spinlock in order to make this atomic_inc() with the
- * atomic_read() in wake_one_more(), otherwise we can race. -arca
- */
-static inline int waking_non_zero_trylock(struct semaphore *sem)
-{
-	unsigned long flags;
-	int ret = 1;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (sem->waking <= 0)
-		atomic_inc(&sem->count);
-	else {
-		sem->waking--;
-		ret = 0;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-#endif