include/asm-cris/semaphore-helper.h

   1 /* $Id: semaphore-helper.h,v 1.3 2001/03/26 15:00:33 orjanf Exp $
   2  *
   3  * SMP- and interrupt-safe semaphores helper functions. Generic versions, no
   4  * optimizations whatsoever...
   5  *
   6  */
   7
   8 #ifndef _ASM_SEMAPHORE_HELPER_H
   9 #define _ASM_SEMAPHORE_HELPER_H
  10
  11 #include <asm/atomic.h>
  12 #include <linux/errno.h>
  13
  14 #define read(a) ((a)->counter)
  15 #define inc(a) (((a)->counter)++)
  16 #define dec(a) (((a)->counter)--)
  17
  18 #define count_inc(a) ((*(a))++)
  19
  20 /*
  21  * These two _must_ execute atomically wrt each other.
  22  */
  23 static inline void wake_one_more(struct semaphore * sem)
  24 {
  25         atomic_inc(&sem->waking);
  26 }
  27
  28 static inline int waking_non_zero(struct semaphore *sem)
  29 {
  30         unsigned long flags;
  31         int ret = 0;
  32
  33         local_irq_save(flags);
  34         if (read(&sem->waking) > 0) {
  35                 dec(&sem->waking);
  36                 ret = 1;
  37         }
  38         local_irq_restore(flags);
  39         return ret;
  40 }
  41
  42 static inline int waking_non_zero_interruptible(struct semaphore *sem,
  43                                                 struct task_struct *tsk)
  44 {
  45         int ret = 0;
  46         unsigned long flags;
  47
  48         local_irq_save(flags);
  49         if (read(&sem->waking) > 0) {
  50                 dec(&sem->waking);
  51                 ret = 1;
  52         } else if (signal_pending(tsk)) {
  53                 inc(&sem->count);
  54                 ret = -EINTR;
  55         }
  56         local_irq_restore(flags);
  57         return ret;
  58 }
  59
  60 static inline int waking_non_zero_trylock(struct semaphore *sem)
  61 {
  62         int ret = 1;
  63         unsigned long flags;
  64
  65         local_irq_save(flags);
  66         if (read(&sem->waking) <= 0)
  67                 inc(&sem->count);
  68         else {
  69                 dec(&sem->waking);
  70                 ret = 0;
  71         }
  72         local_irq_restore(flags);
  73         return ret;
  74 }
  75
  76 #endif /* _ASM_SEMAPHORE_HELPER_H */
  77
  78