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2dc91abe NP |
1 | /* |
2 | * Specialised local-global spinlock. Can only be declared as global variables | |
3 | * to avoid overhead and keep things simple (and we don't want to start using | |
4 | * these inside dynamically allocated structures). | |
5 | * | |
6 | * "local/global locks" (lglocks) can be used to: | |
7 | * | |
8 | * - Provide fast exclusive access to per-CPU data, with exclusive access to | |
9 | * another CPU's data allowed but possibly subject to contention, and to | |
10 | * provide very slow exclusive access to all per-CPU data. | |
11 | * - Or to provide very fast and scalable read serialisation, and to provide | |
12 | * very slow exclusive serialisation of data (not necessarily per-CPU data). | |
13 | * | |
14 | * Brlocks are also implemented as a short-hand notation for the latter use | |
15 | * case. | |
16 | * | |
17 | * Copyright 2009, 2010, Nick Piggin, Novell Inc. | |
18 | */ | |
19 | #ifndef __LINUX_LGLOCK_H | |
20 | #define __LINUX_LGLOCK_H | |
21 | ||
22 | #include <linux/spinlock.h> | |
23 | #include <linux/lockdep.h> | |
24 | #include <linux/percpu.h> | |
e30e2fdf | 25 | #include <linux/cpu.h> |
eea62f83 | 26 | #include <linux/notifier.h> |
2dc91abe | 27 | |
2dc91abe NP |
28 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
29 | #define LOCKDEP_INIT_MAP lockdep_init_map | |
2dc91abe NP |
30 | #else |
31 | #define LOCKDEP_INIT_MAP(a, b, c, d) | |
2dc91abe NP |
32 | #endif |
33 | ||
eea62f83 AK |
34 | struct lglock { |
35 | arch_spinlock_t __percpu *lock; | |
36 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
37 | struct lock_class_key lock_key; | |
38 | struct lockdep_map lock_dep_map; | |
39 | #endif | |
40 | }; | |
2dc91abe NP |
41 | |
42 | #define DEFINE_LGLOCK(name) \ | |
466cab87 | 43 | static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock) \ |
eea62f83 AK |
44 | = __ARCH_SPIN_LOCK_UNLOCKED; \ |
45 | struct lglock name = { .lock = &name ## _lock } | |
46 | ||
4b2c551f LJ |
47 | #define DEFINE_STATIC_LGLOCK(name) \ |
48 | static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock) \ | |
49 | = __ARCH_SPIN_LOCK_UNLOCKED; \ | |
50 | static struct lglock name = { .lock = &name ## _lock } | |
51 | ||
eea62f83 AK |
52 | void lg_lock_init(struct lglock *lg, char *name); |
53 | void lg_local_lock(struct lglock *lg); | |
54 | void lg_local_unlock(struct lglock *lg); | |
55 | void lg_local_lock_cpu(struct lglock *lg, int cpu); | |
56 | void lg_local_unlock_cpu(struct lglock *lg, int cpu); | |
57 | void lg_global_lock(struct lglock *lg); | |
58 | void lg_global_unlock(struct lglock *lg); | |
59 | ||
2dc91abe | 60 | #endif |