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 extern inline void wake_one_more(struct semaphore * sem)
  24 {
  25         atomic_inc(&sem->waking);
  26 }
  27
  28 extern inline int waking_non_zero(struct semaphore *sem)
  29 {
  30         unsigned long flags;
  31         int ret = 0;
  32
  33         local_save_flags(flags);
  34         local_irq_disable();
  35         if (read(&sem->waking) > 0) {
  36                 dec(&sem->waking);
  37                 ret = 1;
  38         }
  39         local_irq_restore(flags);
  40         return ret;
  41 }
  42
  43 extern inline int waking_non_zero_interruptible(struct semaphore *sem,
  44                                                 struct task_struct *tsk)
  45 {
  46         int ret = 0;
  47         unsigned long flags;
  48
  49         local_save_flags(flags);
  50         local_irq_disable();
  51         if (read(&sem->waking) > 0) {
  52                 dec(&sem->waking);
  53                 ret = 1;
  54         } else if (signal_pending(tsk)) {
  55                 inc(&sem->count);
  56                 ret = -EINTR;
  57         }
  58         local_irq_restore(flags);
  59         return ret;
  60 }
  61
  62 extern inline int waking_non_zero_trylock(struct semaphore *sem)
  63 {
  64         int ret = 1;
  65         unsigned long flags;
  66
  67         local_save_flags(flags);
  68         local_irq_disable();
  69         if (read(&sem->waking) <= 0)
  70                 inc(&sem->count);
  71         else {
  72                 dec(&sem->waking);
  73                 ret = 0;
  74         }
  75         local_irq_restore(flags);
  76         return ret;
  77 }
  78
  79 #endif /* _ASM_SEMAPHORE_HELPER_H */
  80
  81