include/linux/rwlock.h

   1 #ifndef __LINUX_RWLOCK_H
   2 #define __LINUX_RWLOCK_H
   3
   4 #ifndef __LINUX_SPINLOCK_H
   5 # error "please don't include this file directly"
   6 #endif
   7
   8 /*
   9  * rwlock related methods
  10  *
  11  * split out from spinlock.h
  12  *
  13  * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
  14  * Released under the General Public License (GPL).
  15  */
  16
  17 #ifdef CONFIG_DEBUG_SPINLOCK
  18   extern void __rwlock_init(rwlock_t *lock, const char *name,
  19                             struct lock_class_key *key);
  20 # define rwlock_init(lock)                                      \
  21 do {                                                            \
  22         static struct lock_class_key __key;                     \
  23                                                                 \
  24         __rwlock_init((lock), #lock, &__key);                   \
  25 } while (0)
  26 #else
  27 # define rwlock_init(lock)                                      \
  28         do { *(lock) = __RW_LOCK_UNLOCKED(lock); } while (0)
  29 #endif
  30
  31 #ifdef CONFIG_DEBUG_SPINLOCK
  32  extern void do_raw_read_lock(rwlock_t *lock) __acquires(lock);
  33  extern int do_raw_read_trylock(rwlock_t *lock);
  34  extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock);
  35  extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock);
  36  extern int do_raw_write_trylock(rwlock_t *lock);
  37  extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock);
  38 #else
  39 # define do_raw_read_lock(rwlock)       do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)
  40 # define do_raw_read_trylock(rwlock)    arch_read_trylock(&(rwlock)->raw_lock)
  41 # define do_raw_read_unlock(rwlock)     do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  42 # define do_raw_write_lock(rwlock)      do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)
  43 # define do_raw_write_trylock(rwlock)   arch_write_trylock(&(rwlock)->raw_lock)
  44 # define do_raw_write_unlock(rwlock)    do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  45 #endif
  46
  47 /*
  48  * Define the various rw_lock methods.  Note we define these
  49  * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  50  * methods are defined as nops in the case they are not required.
  51  */
  52 #define read_trylock(lock)      __cond_lock(lock, _raw_read_trylock(lock))
  53 #define write_trylock(lock)     __cond_lock(lock, _raw_write_trylock(lock))
  54
  55 #define write_lock(lock)        _raw_write_lock(lock)
  56 #define read_lock(lock)         _raw_read_lock(lock)
  57
  58 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  59
  60 #define read_lock_irqsave(lock, flags)                  \
  61         do {                                            \
  62                 typecheck(unsigned long, flags);        \
  63                 flags = _raw_read_lock_irqsave(lock);   \
  64         } while (0)
  65 #define write_lock_irqsave(lock, flags)                 \
  66         do {                                            \
  67                 typecheck(unsigned long, flags);        \
  68                 flags = _raw_write_lock_irqsave(lock);  \
  69         } while (0)
  70
  71 #else
  72
  73 #define read_lock_irqsave(lock, flags)                  \
  74         do {                                            \
  75                 typecheck(unsigned long, flags);        \
  76                 _raw_read_lock_irqsave(lock, flags);    \
  77         } while (0)
  78 #define write_lock_irqsave(lock, flags)                 \
  79         do {                                            \
  80                 typecheck(unsigned long, flags);        \
  81                 _raw_write_lock_irqsave(lock, flags);   \
  82         } while (0)
  83
  84 #endif
  85
  86 #define read_lock_irq(lock)             _raw_read_lock_irq(lock)
  87 #define read_lock_bh(lock)              _raw_read_lock_bh(lock)
  88 #define write_lock_irq(lock)            _raw_write_lock_irq(lock)
  89 #define write_lock_bh(lock)             _raw_write_lock_bh(lock)
  90 #define read_unlock(lock)               _raw_read_unlock(lock)
  91 #define write_unlock(lock)              _raw_write_unlock(lock)
  92 #define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
  93 #define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
  94
  95 #define read_unlock_irqrestore(lock, flags)                     \
  96         do {                                                    \
  97                 typecheck(unsigned long, flags);                \
  98                 _raw_read_unlock_irqrestore(lock, flags);       \
  99         } while (0)
 100 #define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
 101
 102 #define write_unlock_irqrestore(lock, flags)            \
 103         do {                                            \
 104                 typecheck(unsigned long, flags);        \
 105                 _raw_write_unlock_irqrestore(lock, flags);      \
 106         } while (0)
 107 #define write_unlock_bh(lock)           _raw_write_unlock_bh(lock)
 108
 109 #define write_trylock_irqsave(lock, flags) \
 110 ({ \
 111         local_irq_save(flags); \
 112         write_trylock(lock) ? \
 113         1 : ({ local_irq_restore(flags); 0; }); \
 114 })
 115
 116 #ifdef arch_rwlock_is_contended
 117 #define rwlock_is_contended(lock) \
 118          arch_rwlock_is_contended(&(lock)->raw_lock)
 119 #else
 120 #define rwlock_is_contended(lock)       ((void)(lock), 0)
 121 #endif /* arch_rwlock_is_contended */
 122
 123 #endif /* __LINUX_RWLOCK_H */