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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/errno.h>
  14
  15 /*
  16  * These two _must_ execute atomically wrt each other.
  17  */
  18 static inline void wake_one_more(struct semaphore * sem)
  19 {
  20         atomic_inc((atomic_t *)&sem->sleepers);
  21 }
  22
  23 static inline int waking_non_zero(struct semaphore *sem)
  24 {
  25         int ret;
  26         unsigned long flags;
  27
  28         spin_lock_irqsave(&semaphore_wake_lock, flags);
  29         ret = 0;
  30         if (sem->sleepers > 0) {
  31                 sem->sleepers--;
  32                 ret = 1;
  33         }
  34         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  35         return ret;
  36 }
  37
  38 /*
  39  * waking_non_zero_interruptible:
  40  *      1       got the lock
  41  *      0       go to sleep
  42  *      -EINTR  interrupted
  43  */
  44 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  45                                                 struct task_struct *tsk)
  46 {
  47         int ret;
  48         unsigned long flags;
  49
  50         spin_lock_irqsave(&semaphore_wake_lock, flags);
  51         ret = 0;
  52         if (sem->sleepers > 0) {
  53                 sem->sleepers--;
  54                 ret = 1;
  55         } else if (signal_pending(tsk)) {
  56                 atomic_inc(&sem->count);
  57                 ret = -EINTR;
  58         }
  59         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  60         return ret;
  61 }
  62
  63 /*
  64  * waking_non_zero_trylock:
  65  *      1       failed to lock
  66  *      0       got the lock
  67  */
  68 static inline int waking_non_zero_trylock(struct semaphore *sem)
  69 {
  70         int ret;
  71         unsigned long flags;
  72
  73         spin_lock_irqsave(&semaphore_wake_lock, flags);
  74         ret = 1;
  75         if (sem->sleepers <= 0)
  76                 atomic_inc(&sem->count);
  77         else {
  78                 sem->sleepers--;
  79                 ret = 0;
  80         }
  81         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  82         return ret;
  83 }
  84
  85 #endif