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1/*
2 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2008
19 *
20 * Author: Dipankar Sarma <dipankar@in.ibm.com>
21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
22 *
23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
25 *
26 * For detailed explanation of Read-Copy Update mechanism see -
a71fca58 27 * Documentation/RCU
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28 */
29
30#ifndef __LINUX_RCUTREE_H
31#define __LINUX_RCUTREE_H
32
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33struct notifier_block;
34
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35extern void rcu_sched_qs(int cpu);
36extern void rcu_bh_qs(int cpu);
64db4cff 37extern int rcu_needs_cpu(int cpu);
9b2619af 38extern int rcu_expedited_torture_stats(char *page);
64db4cff 39
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40#ifdef CONFIG_TREE_PREEMPT_RCU
41
42extern void __rcu_read_lock(void);
43extern void __rcu_read_unlock(void);
6ebb237b 44extern void synchronize_rcu(void);
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45extern void exit_rcu(void);
46
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47/*
48 * Defined as macro as it is a very low level header
49 * included from areas that don't even know about current
50 */
51#define rcu_preempt_depth() (current->rcu_read_lock_nesting)
52
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53#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
54
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55static inline void __rcu_read_lock(void)
56{
57 preempt_disable();
64db4cff 58}
f41d911f 59
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60static inline void __rcu_read_unlock(void)
61{
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62 preempt_enable();
63}
f41d911f 64
6ebb237b 65#define synchronize_rcu synchronize_sched
16e30811 66
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67static inline void exit_rcu(void)
68{
69}
70
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71static inline int rcu_preempt_depth(void)
72{
73 return 0;
74}
75
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76#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
77
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78static inline void __rcu_read_lock_bh(void)
79{
80 local_bh_disable();
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81}
82static inline void __rcu_read_unlock_bh(void)
83{
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84 local_bh_enable();
85}
86
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87extern void call_rcu_sched(struct rcu_head *head,
88 void (*func)(struct rcu_head *rcu));
019129d5 89extern void synchronize_rcu_expedited(void);
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90
91static inline void synchronize_rcu_bh_expedited(void)
64db4cff 92{
03b042bf 93 synchronize_sched_expedited();
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94}
95
64db4cff 96extern void rcu_check_callbacks(int cpu, int user);
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97
98extern long rcu_batches_completed(void);
99extern long rcu_batches_completed_bh(void);
d6714c22 100extern long rcu_batches_completed_sched(void);
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101extern void rcu_force_quiescent_state(void);
102extern void rcu_bh_force_quiescent_state(void);
103extern void rcu_sched_force_quiescent_state(void);
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104
105#ifdef CONFIG_NO_HZ
106void rcu_enter_nohz(void);
107void rcu_exit_nohz(void);
108#else /* CONFIG_NO_HZ */
109static inline void rcu_enter_nohz(void)
110{
111}
112static inline void rcu_exit_nohz(void)
113{
114}
115#endif /* CONFIG_NO_HZ */
116
1eba8f84 117/* A context switch is a grace period for RCU-sched and RCU-bh. */
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118static inline int rcu_blocking_is_gp(void)
119{
120 return num_online_cpus() == 1;
121}
122
64db4cff 123#endif /* __LINUX_RCUTREE_H */