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 #define DECLARE_MUTEX_LOCKED(name)      __DECLARE_SEMAPHORE_GENERIC(name, 0)
  32
  33 static inline void
  34 sema_init (struct semaphore *sem, int val)
  35 {
  36         *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
  37 }
  38
  39 static inline void
  40 init_MUTEX (struct semaphore *sem)
  41 {
  42         sema_init(sem, 1);
  43 }
  44
  45 static inline void
  46 init_MUTEX_LOCKED (struct semaphore *sem)
  47 {
  48         sema_init(sem, 0);
  49 }
  50
  51 extern void __down (struct semaphore * sem);
  52 extern int  __down_interruptible (struct semaphore * sem);
  53 extern int  __down_trylock (struct semaphore * sem);
  54 extern void __up (struct semaphore * sem);
  55
  56 /*
  57  * Atomically decrement the semaphore's count.  If it goes negative,
  58  * block the calling thread in the TASK_UNINTERRUPTIBLE state.
  59  */
  60 static inline void
  61 down (struct semaphore *sem)
  62 {
  63         might_sleep();
  64         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  65                 __down(sem);
  66 }
  67
  68 /*
  69  * Atomically decrement the semaphore's count.  If it goes negative,
  70  * block the calling thread in the TASK_INTERRUPTIBLE state.
  71  */
  72 static inline int
  73 down_interruptible (struct semaphore * sem)
  74 {
  75         int ret = 0;
  76
  77         might_sleep();
  78         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  79                 ret = __down_interruptible(sem);
  80         return ret;
  81 }
  82
  83 static inline int
  84 down_trylock (struct semaphore *sem)
  85 {
  86         int ret = 0;
  87
  88         if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1)
  89                 ret = __down_trylock(sem);
  90         return ret;
  91 }
  92
  93 static inline void
  94 up (struct semaphore * sem)
  95 {
  96         if (ia64_fetchadd(1, &sem->count.counter, rel) <= -1)
  97                 __up(sem);
  98 }
  99
 100 #endif /* _ASM_IA64_SEMAPHORE_H */