1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
/*
* Specialised local-global spinlock. Can only be declared as global variables
* to avoid overhead and keep things simple (and we don't want to start using
* these inside dynamically allocated structures).
*
* "local/global locks" (lglocks) can be used to:
*
* - Provide fast exclusive access to per-CPU data, with exclusive access to
* another CPU's data allowed but possibly subject to contention, and to
* provide very slow exclusive access to all per-CPU data.
* - Or to provide very fast and scalable read serialisation, and to provide
* very slow exclusive serialisation of data (not necessarily per-CPU data).
*
* Brlocks are also implemented as a short-hand notation for the latter use
* case.
*
* Copyright 2009, 2010, Nick Piggin, Novell Inc.
*/
#ifndef __LINUX_LGLOCK_H
#define __LINUX_LGLOCK_H
#include <linux/spinlock.h>
#include <linux/lockdep.h>
#include <linux/percpu.h>
/* can make br locks by using local lock for read side, global lock for write */
#define br_lock_init(name) name##_lock_init()
#define br_read_lock(name) name##_local_lock()
#define br_read_unlock(name) name##_local_unlock()
#define br_write_lock(name) name##_global_lock_online()
#define br_write_unlock(name) name##_global_unlock_online()
#define DECLARE_BRLOCK(name) DECLARE_LGLOCK(name)
#define DEFINE_BRLOCK(name) DEFINE_LGLOCK(name)
#define lg_lock_init(name) name##_lock_init()
#define lg_local_lock(name) name##_local_lock()
#define lg_local_unlock(name) name##_local_unlock()
#define lg_local_lock_cpu(name, cpu) name##_local_lock_cpu(cpu)
#define lg_local_unlock_cpu(name, cpu) name##_local_unlock_cpu(cpu)
#define lg_global_lock(name) name##_global_lock()
#define lg_global_unlock(name) name##_global_unlock()
#define lg_global_lock_online(name) name##_global_lock_online()
#define lg_global_unlock_online(name) name##_global_unlock_online()
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#define LOCKDEP_INIT_MAP lockdep_init_map
#define DEFINE_LGLOCK_LOCKDEP(name) \
struct lock_class_key name##_lock_key; \
struct lockdep_map name##_lock_dep_map; \
EXPORT_SYMBOL(name##_lock_dep_map)
#else
#define LOCKDEP_INIT_MAP(a, b, c, d)
#define DEFINE_LGLOCK_LOCKDEP(name)
#endif
#define DECLARE_LGLOCK(name) \
extern void name##_lock_init(void); \
extern void name##_local_lock(void); \
extern void name##_local_unlock(void); \
extern void name##_local_lock_cpu(int cpu); \
extern void name##_local_unlock_cpu(int cpu); \
extern void name##_global_lock(void); \
extern void name##_global_unlock(void); \
extern void name##_global_lock_online(void); \
extern void name##_global_unlock_online(void); \
#define DEFINE_LGLOCK(name) \
\
DEFINE_PER_CPU(arch_spinlock_t, name##_lock); \
DEFINE_LGLOCK_LOCKDEP(name); \
\
void name##_lock_init(void) { \
int i; \
LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
for_each_possible_cpu(i) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
*lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; \
} \
} \
EXPORT_SYMBOL(name##_lock_init); \
\
void name##_local_lock(void) { \
arch_spinlock_t *lock; \
preempt_disable(); \
rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_); \
lock = &__get_cpu_var(name##_lock); \
arch_spin_lock(lock); \
} \
EXPORT_SYMBOL(name##_local_lock); \
\
void name##_local_unlock(void) { \
arch_spinlock_t *lock; \
rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_); \
lock = &__get_cpu_var(name##_lock); \
arch_spin_unlock(lock); \
preempt_enable(); \
} \
EXPORT_SYMBOL(name##_local_unlock); \
\
void name##_local_lock_cpu(int cpu) { \
arch_spinlock_t *lock; \
preempt_disable(); \
rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_); \
lock = &per_cpu(name##_lock, cpu); \
arch_spin_lock(lock); \
} \
EXPORT_SYMBOL(name##_local_lock_cpu); \
\
void name##_local_unlock_cpu(int cpu) { \
arch_spinlock_t *lock; \
rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_); \
lock = &per_cpu(name##_lock, cpu); \
arch_spin_unlock(lock); \
preempt_enable(); \
} \
EXPORT_SYMBOL(name##_local_unlock_cpu); \
\
void name##_global_lock_online(void) { \
int i; \
preempt_disable(); \
rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \
for_each_online_cpu(i) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_lock(lock); \
} \
} \
EXPORT_SYMBOL(name##_global_lock_online); \
\
void name##_global_unlock_online(void) { \
int i; \
rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \
for_each_online_cpu(i) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_unlock(lock); \
} \
preempt_enable(); \
} \
EXPORT_SYMBOL(name##_global_unlock_online); \
\
void name##_global_lock(void) { \
int i; \
preempt_disable(); \
rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \
for_each_online_cpu(i) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_lock(lock); \
} \
} \
EXPORT_SYMBOL(name##_global_lock); \
\
void name##_global_unlock(void) { \
int i; \
rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \
for_each_online_cpu(i) { \
arch_spinlock_t *lock; \
lock = &per_cpu(name##_lock, i); \
arch_spin_unlock(lock); \
} \
preempt_enable(); \
} \
EXPORT_SYMBOL(name##_global_unlock);
#endif
|
