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   1 #ifndef _H8300_SEMAPHORE_HELPER_H
   2 #define _H8300_SEMAPHORE_HELPER_H
   3
   4 /*
   5  * SMP- and interrupt-safe semaphores helper functions.
   6  *
   7  * (C) Copyright 1996 Linus Torvalds
   8  *
   9  * based on
  10  * m68k version by Andreas Schwab
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/errno.h>
  15
  16 /*
  17  * These two _must_ execute atomically wrt each other.
  18  */
  19 static inline void wake_one_more(struct semaphore * sem)
  20 {
  21         atomic_inc((atomic_t *)&sem->sleepers);
  22 }
  23
  24 static inline int waking_non_zero(struct semaphore *sem)
  25 {
  26         int ret;
  27         unsigned long flags;
  28
  29         spin_lock_irqsave(&semaphore_wake_lock, flags);
  30         ret = 0;
  31         if (sem->sleepers > 0) {
  32                 sem->sleepers--;
  33                 ret = 1;
  34         }
  35         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  36         return ret;
  37 }
  38
  39 /*
  40  * waking_non_zero_interruptible:
  41  *      1       got the lock
  42  *      0       go to sleep
  43  *      -EINTR  interrupted
  44  */
  45 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  46                                                 struct task_struct *tsk)
  47 {
  48         int ret;
  49         unsigned long flags;
  50
  51         spin_lock_irqsave(&semaphore_wake_lock, flags);
  52         ret = 0;
  53         if (sem->sleepers > 0) {
  54                 sem->sleepers--;
  55                 ret = 1;
  56         } else if (signal_pending(tsk)) {
  57                 atomic_inc(&sem->count);
  58                 ret = -EINTR;
  59         }
  60         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  61         return ret;
  62 }
  63
  64 /*
  65  * waking_non_zero_trylock:
  66  *      1       failed to lock
  67  *      0       got the lock
  68  */
  69 static inline int waking_non_zero_trylock(struct semaphore *sem)
  70 {
  71         int ret;
  72         unsigned long flags;
  73
  74         spin_lock_irqsave(&semaphore_wake_lock, flags);
  75         ret = 1;
  76         if (sem->sleepers <= 0)
  77                 atomic_inc(&sem->count);
  78         else {
  79                 sem->sleepers--;
  80                 ret = 0;
  81         }
  82         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  83         return ret;
  84 }
  85
  86 #endif