#ifndef __LINUX_RWLOCK_H
  #define __LINUX_RWLOCK_H
  
  #ifndef __LINUX_SPINLOCK_H
  # error "please don't include this file directly"
  #endif
  
  /*
   * rwlock related methods
   *
   * split out from spinlock.h
   *
   * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
   * Released under the General Public License (GPL).
   */
  
  #ifdef CONFIG_DEBUG_SPINLOCK
    extern void __rwlock_init(rwlock_t *lock, const char *name,
  			    struct lock_class_key *key);
  # define rwlock_init(lock)					\
  do {								\
  	static struct lock_class_key __key;			\
  								\
  	__rwlock_init((lock), #lock, &__key);			\
  } while (0)
  #else
  # define rwlock_init(lock)					\
  	do { *(lock) = __RW_LOCK_UNLOCKED(lock); } while (0)
  #endif
  
  #ifdef CONFIG_DEBUG_SPINLOCK

   extern void do_raw_read_lock(rwlock_t *lock) __acquires(lock);

  #define do_raw_read_lock_flags(lock, flags) do_raw_read_lock(lock)
   extern int do_raw_read_trylock(rwlock_t *lock);

   extern void do_raw_read_unlock(rwlock_t *lock) __releases(lock);
   extern void do_raw_write_lock(rwlock_t *lock) __acquires(lock);

  #define do_raw_write_lock_flags(lock, flags) do_raw_write_lock(lock)
   extern int do_raw_write_trylock(rwlock_t *lock);

   extern void do_raw_write_unlock(rwlock_t *lock) __releases(lock);

  #else

  # define do_raw_read_lock(rwlock)	do {__acquire(lock); arch_read_lock(&(rwlock)->raw_lock); } while (0)

  # define do_raw_read_lock_flags(lock, flags) \

  		do {__acquire(lock); arch_read_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)

  # define do_raw_read_trylock(rwlock)	arch_read_trylock(&(rwlock)->raw_lock)

  # define do_raw_read_unlock(rwlock)	do {arch_read_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)
  # define do_raw_write_lock(rwlock)	do {__acquire(lock); arch_write_lock(&(rwlock)->raw_lock); } while (0)

  # define do_raw_write_lock_flags(lock, flags) \

  		do {__acquire(lock); arch_write_lock_flags(&(lock)->raw_lock, *(flags)); } while (0)

  # define do_raw_write_trylock(rwlock)	arch_write_trylock(&(rwlock)->raw_lock)

  # define do_raw_write_unlock(rwlock)	do {arch_write_unlock(&(rwlock)->raw_lock); __release(lock); } while (0)

  #endif

  #define read_can_lock(rwlock)		arch_read_can_lock(&(rwlock)->raw_lock)
  #define write_can_lock(rwlock)		arch_write_can_lock(&(rwlock)->raw_lock)

  
  /*
   * Define the various rw_lock methods.  Note we define these
   * regardless of whether CONFIG_SMP or CONFIG_PREEMPT are set. The various
   * methods are defined as nops in the case they are not required.
   */

  #define read_trylock(lock)	__cond_lock(lock, _raw_read_trylock(lock))
  #define write_trylock(lock)	__cond_lock(lock, _raw_write_trylock(lock))

  #define write_lock(lock)	_raw_write_lock(lock)
  #define read_lock(lock)		_raw_read_lock(lock)

  
  #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
  
  #define read_lock_irqsave(lock, flags)			\
  	do {						\
  		typecheck(unsigned long, flags);	\

  		flags = _raw_read_lock_irqsave(lock);	\

  	} while (0)
  #define write_lock_irqsave(lock, flags)			\
  	do {						\
  		typecheck(unsigned long, flags);	\

  		flags = _raw_write_lock_irqsave(lock);	\

  	} while (0)
  
  #else
  
  #define read_lock_irqsave(lock, flags)			\
  	do {						\
  		typecheck(unsigned long, flags);	\

  		_raw_read_lock_irqsave(lock, flags);	\

  	} while (0)
  #define write_lock_irqsave(lock, flags)			\
  	do {						\
  		typecheck(unsigned long, flags);	\

  		_raw_write_lock_irqsave(lock, flags);	\

  	} while (0)
  
  #endif

  #define read_lock_irq(lock)		_raw_read_lock_irq(lock)
  #define read_lock_bh(lock)		_raw_read_lock_bh(lock)
  #define write_lock_irq(lock)		_raw_write_lock_irq(lock)
  #define write_lock_bh(lock)		_raw_write_lock_bh(lock)
  #define read_unlock(lock)		_raw_read_unlock(lock)
  #define write_unlock(lock)		_raw_write_unlock(lock)
  #define read_unlock_irq(lock)		_raw_read_unlock_irq(lock)
  #define write_unlock_irq(lock)		_raw_write_unlock_irq(lock)
  
  #define read_unlock_irqrestore(lock, flags)			\
  	do {							\
  		typecheck(unsigned long, flags);		\
  		_raw_read_unlock_irqrestore(lock, flags);	\

  	} while (0)

  #define read_unlock_bh(lock)		_raw_read_unlock_bh(lock)

  
  #define write_unlock_irqrestore(lock, flags)		\
  	do {						\
  		typecheck(unsigned long, flags);	\

  		_raw_write_unlock_irqrestore(lock, flags);	\

  	} while (0)

  #define write_unlock_bh(lock)		_raw_write_unlock_bh(lock)

  
  #define write_trylock_irqsave(lock, flags) \
  ({ \
  	local_irq_save(flags); \
  	write_trylock(lock) ? \
  	1 : ({ local_irq_restore(flags); 0; }); \
  })
  
  #endif /* __LINUX_RWLOCK_H */