include/asm-ia64/semaphore.h

   1 #ifndef _ASM_IA64_SEMAPHORE_H
   2 #define _ASM_IA64_SEMAPHORE_H
   3
   4 /*
   5  * Copyright (C) 1998-2000 Hewlett-Packard Co
   6  * Copyright (C) 1998-2000 David Mosberger-Tang <davidm@hpl.hp.com>
   7  */
   8
   9 #include <linux/wait.h>
  10 #include <linux/rwsem.h>
  11
  12 #include <asm/atomic.h>
  13
  14 struct semaphore {
  15         atomic_t count;
  16         int sleepers;
  17         wait_queue_head_t wait;
  18 };
  19
  20 #define __SEMAPHORE_INITIALIZER(name, n)                                \
  21 {                                                                       \
  22         .count          = ATOMIC_INIT(n),                               \
  23         .sleepers       = 0,                                            \
  24         .wait           = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)    \
  25 }
  26
  27 #define __DECLARE_SEMAPHORE_GENERIC(name,count)                                 \
  28         struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
  29
  30 #define DECLARE_MUTEX(name)             __DECLARE_SEMAPHORE_GENERIC(name, 1)
  31
  32 static inline void
  33 sema_init (struct semaphore *sem, int val)
  34 {
  35         *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
  36 }
  37
  38 static inline void
  39 init_MUTEX (struct semaphore *sem)
  40 {
  41         sema_init(sem, 1);
  42 }
  43
  44 static inline void
  45 init_MUTEX_LOCKED (struct semaphore *sem)
  46 {
  47         sema_init(sem, 0);
  48 }
  49
  50 extern void __down (struct semaphore * sem);
  51 extern int  __down_interruptible (struct semaphore * sem);
  52 extern int  __down_trylock (struct semaphore * sem);
  53 extern void __up (struct semaphore * sem);
  54
  55 /*
  56  * Atomically decrement the semaphore's count.  If it goes negative,
  57  * block the calling thread in the TASK_UNINTERRUPTIBLE state.
  58  */
  59 static inline void
  60 down (struct semaphore *sem)
  61 {
  62         might_sleep();
  63         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  64                 __down(sem);
  65 }
  66
  67 /*
  68  * Atomically decrement the semaphore's count.  If it goes negative,
  69  * block the calling thread in the TASK_INTERRUPTIBLE state.
  70  */
  71 static inline int
  72 down_interruptible (struct semaphore * sem)
  73 {
  74         int ret = 0;
  75
  76         might_sleep();
  77         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  78                 ret = __down_interruptible(sem);
  79         return ret;
  80 }
  81
  82 static inline int
  83 down_trylock (struct semaphore *sem)
  84 {
  85         int ret = 0;
  86
  87         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  88                 ret = __down_trylock(sem);
  89         return ret;
  90 }
  91
  92 static inline void
  93 up (struct semaphore * sem)
  94 {
  95         if (ia64_fetchadd(1, &sem->count.counter, rel) <= -1)
  96                 __up(sem);
  97 }
  98
  99 #endif /* _ASM_IA64_SEMAPHORE_H */