patch-2.2.4 linux/include/asm-ppc/semaphore.h

• Lines: 93
• Date: Wed Mar 10 21:30:32 1999
• Orig file: v2.2.3/linux/include/asm-ppc/semaphore.h
• Orig date: Tue Jan 19 11:32:53 1999

diff -u --recursive --new-file v2.2.3/linux/include/asm-ppc/semaphore.h linux/include/asm-ppc/semaphore.h
@@ -13,66 +13,54 @@
 struct semaphore {
 	atomic_t count;
 	atomic_t waking;
-	struct wait_queue * wait;
+	struct wait_queue *wait;
 };
 
-#define MUTEX ((struct semaphore) { ATOMIC_INIT(1), ATOMIC_INIT(0), NULL })
-#define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), ATOMIC_INIT(0), NULL })
+#define sema_init(sem, val)	atomic_set(&((sem)->count), (val))
+
+#define MUTEX		((struct semaphore) \
+			 { ATOMIC_INIT(1), ATOMIC_INIT(0), NULL })
+#define MUTEX_LOCKED	((struct semaphore) \
+			 { ATOMIC_INIT(0), ATOMIC_INIT(0), NULL })
 
 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);
 
-#define sema_init(sem, val)	atomic_set(&((sem)->count), (val))
-
-/*
- * These two _must_ execute atomically wrt each other.
- *
- * This is trivially done with load_locked/store_cond,
- * i.e. load with reservation and store conditional on the ppc.
- */
-
-static inline void wake_one_more(struct semaphore * sem)
+extern inline void down(struct semaphore * sem)
 {
-	atomic_inc(&sem->waking);
+	if (atomic_dec_return(&sem->count) >= 0)
+		wmb();
+	else
+		__down(sem);
 }
 
-static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
+extern inline int down_interruptible(struct semaphore * sem)
 {
-	int ret, tmp;
-
-	__asm__ __volatile__(
-		"1:	lwarx %1,0,%2\n"
-		"	cmpwi 0,%1,0\n"
-		"	addic %1,%1,-1\n"
-		"	ble- 2f\n"
-		"	stwcx. %1,0,%2\n"
-		"	bne- 1b\n"
-		"	li %0,1\n"
-		"2:"
-		: "=r" (ret), "=&r" (tmp)
-		: "r" (&sem->waking), "0" (0)
-		: "cr0", "memory");
+	int ret = 0;
 
+	if (atomic_dec_return(&sem->count) >= 0)
+		wmb();
+	else
+		ret = __down_interruptible(sem);
 	return ret;
 }
 
-extern inline void down(struct semaphore * sem)
-{
-	if (atomic_dec_return(&sem->count) < 0)
-		__down(sem);
-}
-
-extern inline int down_interruptible(struct semaphore * sem)
+extern inline int down_trylock(struct semaphore * sem)
 {
 	int ret = 0;
-	if (atomic_dec_return(&sem->count) < 0)
-		ret = __down_interruptible(sem);
+
+	if (atomic_dec_return(&sem->count) >= 0)
+		wmb();
+	else
+		ret = __down_trylock(sem);
 	return ret;
 }
 
 extern inline void up(struct semaphore * sem)
 {
+	mb();
 	if (atomic_inc_return(&sem->count) <= 0)
 		__up(sem);
 }