include/linux/of.h: make for_each_child_of_node() reference its args when CONFIG_OF=n
[deliverable/linux.git] / include / linux / lglock.h
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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
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28#ifdef CONFIG_DEBUG_LOCK_ALLOC
29#define LOCKDEP_INIT_MAP lockdep_init_map
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30#else
31#define LOCKDEP_INIT_MAP(a, b, c, d)
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32#endif
33
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34struct 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};
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41
42#define DEFINE_LGLOCK(name) \
466cab87 43 static DEFINE_PER_CPU(arch_spinlock_t, name ## _lock) \
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44 = __ARCH_SPIN_LOCK_UNLOCKED; \
45 struct lglock name = { .lock = &name ## _lock }
46
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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
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52void lg_lock_init(struct lglock *lg, char *name);
53void lg_local_lock(struct lglock *lg);
54void lg_local_unlock(struct lglock *lg);
55void lg_local_lock_cpu(struct lglock *lg, int cpu);
56void lg_local_unlock_cpu(struct lglock *lg, int cpu);
57void lg_global_lock(struct lglock *lg);
58void lg_global_unlock(struct lglock *lg);
59
2dc91abe 60#endif
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