include/linux/spinlock_up.h

   1 #ifndef __LINUX_SPINLOCK_UP_H
   2 #define __LINUX_SPINLOCK_UP_H
   3
   4 #ifndef __LINUX_SPINLOCK_H
   5 # error "please don't include this file directly"
   6 #endif
   7
   8 /*
   9  * include/linux/spinlock_up.h - UP-debug version of spinlocks.
  10  *
  11  * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
  12  * Released under the General Public License (GPL).
  13  *
  14  * In the debug case, 1 means unlocked, 0 means locked. (the values
  15  * are inverted, to catch initialization bugs)
  16  *
  17  * No atomicity anywhere, we are on UP.
  18  */
  19
  20 #ifdef CONFIG_DEBUG_SPINLOCK
  21
  22 #define __raw_spin_is_locked(x)         ((x)->slock == 0)
  23
  24 static inline void __raw_spin_lock(raw_spinlock_t *lock)
  25 {
  26         lock->slock = 0;
  27 }
  28
  29 static inline void
  30 __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
  31 {
  32         local_irq_save(flags);
  33         lock->slock = 0;
  34 }
  35
  36 static inline int __raw_spin_trylock(raw_spinlock_t *lock)
  37 {
  38         char oldval = lock->slock;
  39
  40         lock->slock = 0;
  41
  42         return oldval > 0;
  43 }
  44
  45 static inline void __raw_spin_unlock(raw_spinlock_t *lock)
  46 {
  47         lock->slock = 1;
  48 }
  49
  50 /*
  51  * Read-write spinlocks. No debug version.
  52  */
  53 #define __raw_read_lock(lock)           do { (void)(lock); } while (0)
  54 #define __raw_write_lock(lock)          do { (void)(lock); } while (0)
  55 #define __raw_read_trylock(lock)        ({ (void)(lock); 1; })
  56 #define __raw_write_trylock(lock)       ({ (void)(lock); 1; })
  57 #define __raw_read_unlock(lock)         do { (void)(lock); } while (0)
  58 #define __raw_write_unlock(lock)        do { (void)(lock); } while (0)
  59
  60 #else /* DEBUG_SPINLOCK */
  61 #define __raw_spin_is_locked(lock)      ((void)(lock), 0)
  62 /* for sched.c and kernel_lock.c: */
  63 # define __raw_spin_lock(lock)          do { (void)(lock); } while (0)
  64 # define __raw_spin_unlock(lock)        do { (void)(lock); } while (0)
  65 # define __raw_spin_trylock(lock)       ({ (void)(lock); 1; })
  66 #endif /* DEBUG_SPINLOCK */
  67
  68 #define __raw_read_can_lock(lock)       (((void)(lock), 1))
  69 #define __raw_write_can_lock(lock)      (((void)(lock), 1))
  70
  71 #define __raw_spin_unlock_wait(lock) \
  72                 do { cpu_relax(); } while (__raw_spin_is_locked(lock))
  73
  74 #endif /* __LINUX_SPINLOCK_UP_H */