include/asm-m68knommu/semaphore-helper.h

   1 #ifndef _M68K_SEMAPHORE_HELPER_H
   2 #define _M68K_SEMAPHORE_HELPER_H
   3
   4 /*
   5  * SMP- and interrupt-safe semaphores helper functions.
   6  *
   7  * (C) Copyright 1996 Linus Torvalds
   8  *
   9  * m68k version by Andreas Schwab
  10  */
  11
  12
  13 /*
  14  * These two _must_ execute atomically wrt each other.
  15  */
  16 static inline void wake_one_more(struct semaphore * sem)
  17 {
  18         atomic_inc(&sem->waking);
  19 }
  20
  21 static inline int waking_non_zero(struct semaphore *sem)
  22 {
  23         int ret;
  24         unsigned long flags;
  25
  26         spin_lock_irqsave(&semaphore_wake_lock, flags);
  27         ret = 0;
  28         if (atomic_read(&sem->waking) > 0) {
  29                 atomic_dec(&sem->waking);
  30                 ret = 1;
  31         }
  32         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  33         return ret;
  34 }
  35
  36 /*
  37  * waking_non_zero_interruptible:
  38  *      1       got the lock
  39  *      0       go to sleep
  40  *      -EINTR  interrupted
  41  */
  42 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  43                                                 struct task_struct *tsk)
  44 {
  45         int ret;
  46         unsigned long flags;
  47
  48         spin_lock_irqsave(&semaphore_wake_lock, flags);
  49         ret = 0;
  50         if (atomic_read(&sem->waking) > 0) {
  51                 atomic_dec(&sem->waking);
  52                 ret = 1;
  53         } else if (signal_pending(tsk)) {
  54                 atomic_inc(&sem->count);
  55                 ret = -EINTR;
  56         }
  57         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  58         return ret;
  59 }
  60
  61 /*
  62  * waking_non_zero_trylock:
  63  *      1       failed to lock
  64  *      0       got the lock
  65  */
  66 static inline int waking_non_zero_trylock(struct semaphore *sem)
  67 {
  68         int ret;
  69         unsigned long flags;
  70
  71         spin_lock_irqsave(&semaphore_wake_lock, flags);
  72         ret = 1;
  73         if (atomic_read(&sem->waking) > 0) {
  74                 atomic_dec(&sem->waking);
  75                 ret = 0;
  76         } else
  77                 atomic_inc(&sem->count);
  78         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  79         return ret;
  80 }
  81
  82 #endif