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, 1 insertions, 133 deletions

diff --git a/include/asm-cris/semaphore.h b/include/asm-cris/semaphore.h
index 31a4ac448195..d9b2034ed1d2 100644
--- a/include/asm-cris/semaphore.h
+++ b/include/asm-cris/semaphore.h
@@ -1,133 +1 @@
-/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */
-
-/* On the i386 these are coded in asm, perhaps we should as well. Later.. */
-
-#ifndef _CRIS_SEMAPHORE_H
-#define _CRIS_SEMAPHORE_H
-
-#define RW_LOCK_BIAS             0x01000000
-
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/rwsem.h>
-
-#include <asm/system.h>
-#include <asm/atomic.h>
-
-/*
- * CRIS semaphores, implemented in C-only so far. 
- */
-
-struct semaphore {
-	atomic_t count;
-	atomic_t waking;
-	wait_queue_head_t wait;
-};
-
-#define __SEMAPHORE_INITIALIZER(name, n)				\
-{									\
-	.count		= ATOMIC_INIT(n),				\
-	.waking		= ATOMIC_INIT(0),				\
-	.wait		= __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
-}
-
-#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
-        struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
-
-#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
-
-static inline void sema_init(struct semaphore *sem, int val)
-{
-	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
-}
-
-static inline void init_MUTEX (struct semaphore *sem)
-{
-        sema_init(sem, 1);
-}
-
-static inline void init_MUTEX_LOCKED (struct semaphore *sem)
-{
-        sema_init(sem, 0);
-}
-
-extern void __down(struct semaphore * sem);
-extern int __down_interruptible(struct semaphore * sem);
-extern int __down_trylock(struct semaphore * sem);
-extern void __up(struct semaphore * sem);
-
-/* notice - we probably can do cli/sti here instead of saving */
-
-static inline void down(struct semaphore * sem)
-{
-	unsigned long flags;
-	int failed;
-
-	might_sleep();
-
-	/* atomically decrement the semaphores count, and if its negative, we wait */
-	cris_atomic_save(sem, flags);
-	failed = --(sem->count.counter) < 0;
-	cris_atomic_restore(sem, flags);
-	if(failed) {
-		__down(sem);
-	}
-}
-
-/*
- * This version waits in interruptible state so that the waiting
- * process can be killed.  The down_interruptible routine
- * returns negative for signalled and zero for semaphore acquired.
- */
-
-static inline int down_interruptible(struct semaphore * sem)
-{
-	unsigned long flags;
-	int failed;
-
-	might_sleep();
-
-	/* atomically decrement the semaphores count, and if its negative, we wait */
-	cris_atomic_save(sem, flags);
-	failed = --(sem->count.counter) < 0;
-	cris_atomic_restore(sem, flags);
-	if(failed)
-		failed = __down_interruptible(sem);
-	return(failed);
-}
-
-static inline int down_trylock(struct semaphore * sem)
-{
-	unsigned long flags;
-	int failed;
-
-	cris_atomic_save(sem, flags);
-	failed = --(sem->count.counter) < 0;
-	cris_atomic_restore(sem, flags);
-	if(failed)
-		failed = __down_trylock(sem);
-	return(failed);
-
-}
-
-/*
- * Note! This is subtle. We jump to wake people up only if
- * the semaphore was negative (== somebody was waiting on it).
- * The default case (no contention) will result in NO
- * jumps for both down() and up().
- */
-static inline void up(struct semaphore * sem)
-{  
-	unsigned long flags;
-	int wakeup;
-
-	/* atomically increment the semaphores count, and if it was negative, we wake people */
-	cris_atomic_save(sem, flags);
-	wakeup = ++(sem->count.counter) <= 0;
-	cris_atomic_restore(sem, flags);
-	if(wakeup) {
-		__up(sem);
-	}
-}
-
-#endif
+#include <linux/semaphore.h>