text: /*
   *  include/asm-s390/semaphore.h
   *
   *  S390 version
   *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   *
   *  Derived from "include/asm-i386/semaphore.h"
   *    (C) Copyright 1996 Linus Torvalds
   */
  
  #ifndef _S390_SEMAPHORE_H
  #define _S390_SEMAPHORE_H
  
  #include <asm/system.h>
  #include <asm/atomic.h>
  #include <linux/wait.h>
  #include <linux/rwsem.h>
  
  struct semaphore {
  	atomic_t count;
  	int sleepers;
  	wait_queue_head_t wait;
  };
  
  #define __SEM_DEBUG_INIT(name)
  
  #define __SEMAPHORE_INITIALIZER(name,count) \
  { ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
  	__SEM_DEBUG_INIT(name) }
  
  #define __MUTEX_INITIALIZER(name) \
  	__SEMAPHORE_INITIALIZER(name,1)
  
  #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
  	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
  
  #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
  #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
  
  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);
  }
  
  asmlinkage void __down_failed(void /* special register calling convention */);
  asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
  asmlinkage int  __down_failed_trylock(void  /* params in registers */);
  asmlinkage void __up_wakeup(void /* special register calling convention */);
  
  asmlinkage void __down(struct semaphore * sem);
  asmlinkage int  __down_interruptible(struct semaphore * sem);
  asmlinkage int  __down_trylock(struct semaphore * sem);
  asmlinkage void __up(struct semaphore * sem);
  
  static inline void down(struct semaphore * sem)
  {
  	if (atomic_dec_return(&sem->count) < 0)
  		__down(sem);
  }
  
  static inline int down_interruptible(struct semaphore * sem)
  {
  	int ret = 0;
  
  	if (atomic_dec_return(&sem->count) < 0)
  		ret = __down_interruptible(sem);
  	return ret;
  }
  
  static inline int down_trylock(struct semaphore * sem)
  {
  	int ret = 0;
  
  	if (atomic_dec_return(&sem->count) < 0)
  		ret = __down_trylock(sem);
  	return ret;
  }
  
  static inline void up(struct semaphore * sem)
  {
  	if (atomic_inc_return(&sem->count) <= 0)
  		__up(sem);
  }
  
  static inline int sem_getcount(struct semaphore *sem)
  {
  	return atomic_read(&sem->count);
  }
  
  #endif
  