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

source code of linux/include/linux/rwlock.h