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 #include <linux/config.h>
  13
  14 /*
  15  * These two _must_ execute atomically wrt each other.
  16  */
  17 static inline void wake_one_more(struct semaphore * sem)
  18 {
  19         atomic_inc(&sem->waking);
  20 }
  21
  22 static inline int waking_non_zero(struct semaphore *sem)
  23 {
  24         int ret;
  25         unsigned long flags;
  26
  27         spin_lock_irqsave(&semaphore_wake_lock, flags);
  28         ret = 0;
  29         if (atomic_read(&sem->waking) > 0) {
  30                 atomic_dec(&sem->waking);
  31                 ret = 1;
  32         }
  33         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  34         return ret;
  35 }
  36
  37 /*
  38  * waking_non_zero_interruptible:
  39  *      1       got the lock
  40  *      0       go to sleep
  41  *      -EINTR  interrupted
  42  */
  43 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  44                                                 struct task_struct *tsk)
  45 {
  46         int ret;
  47         unsigned long flags;
  48
  49         spin_lock_irqsave(&semaphore_wake_lock, flags);
  50         ret = 0;
  51         if (atomic_read(&sem->waking) > 0) {
  52                 atomic_dec(&sem->waking);
  53                 ret = 1;
  54         } else if (signal_pending(tsk)) {
  55                 atomic_inc(&sem->count);
  56                 ret = -EINTR;
  57         }
  58         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  59         return ret;
  60 }
  61
  62 /*
  63  * waking_non_zero_trylock:
  64  *      1       failed to lock
  65  *      0       got the lock
  66  */
  67 static inline int waking_non_zero_trylock(struct semaphore *sem)
  68 {
  69         int ret;
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&semaphore_wake_lock, flags);
  73         ret = 1;
  74         if (atomic_read(&sem->waking) > 0) {
  75                 atomic_dec(&sem->waking);
  76                 ret = 0;
  77         } else
  78                 atomic_inc(&sem->count);
  79         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
  80         return ret;
  81 }
  82
  83 #endif