linux/include/linux/rwlock.h
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   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#define do_raw_read_lock_flags(lock, flags) do_raw_read_lock(lock)
  34 extern int do_raw_read_trylock(rwlock_t *lock);
  35 extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock);
  36 extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock);
  37#define do_raw_write_lock_flags(lock, flags) do_raw_write_lock(lock)
  38 extern int do_raw_write_trylock(rwlock_t *lock);
  39 extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock);
  40#else
  41# define do_raw_read_lock(rwlock)       do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)
  42# define do_raw_read_lock_flags(lock, flags) \
  43                do {__acquire(lock); arch_read_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  44# define do_raw_read_trylock(rwlock)    arch_read_trylock(&(rwlock)->raw_lock)
  45# define do_raw_read_unlock(rwlock)     do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  46# define do_raw_write_lock(rwlock)      do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)
  47# define do_raw_write_lock_flags(lock, flags) \
  48                do {__acquire(lock); arch_write_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)
  49# define do_raw_write_trylock(rwlock)   arch_write_trylock(&(rwlock)->raw_lock)
  50# define do_raw_write_unlock(rwlock)    do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  51#endif
  52
  53#define read_can_lock(rwlock)           arch_read_can_lock(&(rwlock)->raw_lock)
  54#define write_can_lock(rwlock)          arch_write_can_lock(&(rwlock)->raw_lock)
  55
  56/*
  57 * Define the various rw_lock methods.  Note we define these
  58 * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
  59 * methods are defined as nops in the case they are not required.
  60 */
  61#define read_trylock(lock)      __cond_lock(lock, _raw_read_trylock(lock))
  62#define write_trylock(lock)     __cond_lock(lock, _raw_write_trylock(lock))
  63
  64#define write_lock(lock)        _raw_write_lock(lock)
  65#define read_lock(lock)         _raw_read_lock(lock)
  66
  67#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  68
  69#define read_lock_irqsave(lock, flags)                  \
  70        do {                                            \
  71                typecheck(unsigned long, flags);        \
  72                flags = _raw_read_lock_irqsave(lock);   \
  73        } while (0)
  74#define write_lock_irqsave(lock, flags)                 \
  75        do {                                            \
  76                typecheck(unsigned long, flags);        \
  77                flags = _raw_write_lock_irqsave(lock);  \
  78        } while (0)
  79
  80#else
  81
  82#define read_lock_irqsave(lock, flags)                  \
  83        do {                                            \
  84                typecheck(unsigned long, flags);        \
  85                _raw_read_lock_irqsave(lock, flags);    \
  86        } while (0)
  87#define write_lock_irqsave(lock, flags)                 \
  88        do {                                            \
  89                typecheck(unsigned long, flags);        \
  90                _raw_write_lock_irqsave(lock, flags);   \
  91        } while (0)
  92
  93#endif
  94
  95#define read_lock_irq(lock)             _raw_read_lock_irq(lock)
  96#define read_lock_bh(lock)              _raw_read_lock_bh(lock)
  97#define write_lock_irq(lock)            _raw_write_lock_irq(lock)
  98#define write_lock_bh(lock)             _raw_write_lock_bh(lock)
  99#define read_unlock(lock)               _raw_read_unlock(lock)
 100#define write_unlock(lock)              _raw_write_unlock(lock)
 101#define read_unlock_irq(lock)           _raw_read_unlock_irq(lock)
 102#define write_unlock_irq(lock)          _raw_write_unlock_irq(lock)
 103
 104#define read_unlock_irqrestore(lock, flags)                     \
 105        do {                                                    \
 106                typecheck(unsigned long, flags);                \
 107                _raw_read_unlock_irqrestore(lock, flags);       \
 108        } while (0)
 109#define read_unlock_bh(lock)            _raw_read_unlock_bh(lock)
 110
 111#define write_unlock_irqrestore(lock, flags)            \
 112        do {                                            \
 113                typecheck(unsigned long, flags);        \
 114                _raw_write_unlock_irqrestore(lock, flags);      \
 115        } while (0)
 116#define write_unlock_bh(lock)           _raw_write_unlock_bh(lock)
 117
 118#define write_trylock_irqsave(lock, flags) \
 119({ \
 120        local_irq_save(flags); \
 121        write_trylock(lock) ? \
 122        1 : ({ local_irq_restore(flags); 0; }); \
 123})
 124
 125#endif /* __LINUX_RWLOCK_H */
 126
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