rwlock.h

  1#ifndef __LINUX_RWLOCK_H
  2#define __LINUX_RWLOCK_H
  3
  4#ifndef __LINUX_INSIDE_SPINLOCK_H
  5# error "Please do not 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 */