LXR linux/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)                                      \
  21do {                                                            \
  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#ifdef CONFIG_DEBUG_LOCK_ALLOC
  59#define write_lock_nested(lock, subclass)       _raw_write_lock_nested(lock, subclass)
  60#else
  61#define write_lock_nested(lock, subclass)       _raw_write_lock(lock)
  62#endif
  63
  64#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  65
  66#define read_lock_irqsave(lock, flags)                  \
  67        do {                                            \
  68                typecheck(unsigned long, flags);        \
  69                flags = _raw_read_lock_irqsave(lock);   \
  70        } while (0)
  71#define write_lock_irqsave(lock, flags)                 \
  72        do {                                            \
  73                typecheck(unsigned long, flags);        \
  74                flags = _raw_write_lock_irqsave(lock);  \
  75        } while (0)
  76
  77#else
  78
  79#define read_lock_irqsave(lock, flags)                  \
  80        do {                                            \
  81                typecheck(unsigned long, flags);        \
  82                _raw_read_lock_irqsave(lock, flags);    \
  83        } while (0)
  84#define write_lock_irqsave(lock, flags)                 \
  85        do {                                            \
  86                typecheck(unsigned long, flags);        \
  87                _raw_write_lock_irqsave(lock, flags);   \
  88        } while (0)
  89
  90#endif
  91
  92#define read_lock_irq(lock)             _raw_read_lock_irq(lock)
  93#define read_lock_bh(lock)              _raw_read_lock_bh(lock)
  94#define write_lock_irq(lock)            _raw_write_lock_irq(lock)
  95#define write_lock_bh(lock)             _raw_write_lock_bh(lock)
  96#define read_unlock(lock)               _raw_read_unlock(lock)
  97#define write_unlock(lock)              _raw_write_unlock(lock)
  98#define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
  99#define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
 100
 101#define read_unlock_irqrestore(lock, flags)                     \
 102        do {                                                    \
 103                typecheck(unsigned long, flags);                \
 104                _raw_read_unlock_irqrestore(lock, flags);       \
 105        } while (0)
 106#define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
 107
 108#define write_unlock_irqrestore(lock, flags)            \
 109        do {                                            \
 110                typecheck(unsigned long, flags);        \
 111                _raw_write_unlock_irqrestore(lock, flags);      \
 112        } while (0)
 113#define write_unlock_bh(lock)           _raw_write_unlock_bh(lock)
 114
 115#define write_trylock_irqsave(lock, flags) \
 116({ \
 117        local_irq_save(flags); \
 118        write_trylock(lock) ? \
 119        1 : ({ local_irq_restore(flags); 0; }); \
 120})
 121
 122#ifdef arch_rwlock_is_contended
 123#define rwlock_is_contended(lock) \
 124         arch_rwlock_is_contended(&(lock)->raw_lock)
 125#else
 126#define rwlock_is_contended(lock)       ((void)(lock), 0)
 127#endif /* arch_rwlock_is_contended */
 128
 129#endif /* __LINUX_RWLOCK_H */
 130