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1/*
2 * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
21 *
22 * For detailed explanation of Read-Copy Update mechanism see -
23 * Documentation/RCU
24 */
25#ifndef __LINUX_TINY_H
26#define __LINUX_TINY_H
27
28#include <linux/cache.h>
29
30static inline void rcu_init(void)
31{
32}
33
34static inline void rcu_barrier_bh(void)
35{
36 wait_rcu_gp(call_rcu_bh);
37}
38
39static inline void rcu_barrier_sched(void)
40{
41 wait_rcu_gp(call_rcu_sched);
42}
43
44#ifdef CONFIG_TINY_RCU
45
46static inline void synchronize_rcu_expedited(void)
47{
48 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
49}
50
51static inline void rcu_barrier(void)
52{
53 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
54}
55
56#else /* #ifdef CONFIG_TINY_RCU */
57
58void synchronize_rcu_expedited(void);
59
60static inline void rcu_barrier(void)
61{
62 wait_rcu_gp(call_rcu);
63}
64
65#endif /* #else #ifdef CONFIG_TINY_RCU */
66
67static inline void synchronize_rcu_bh(void)
68{
69 synchronize_sched();
70}
71
72static inline void synchronize_rcu_bh_expedited(void)
73{
74 synchronize_sched();
75}
76
77static inline void synchronize_sched_expedited(void)
78{
79 synchronize_sched();
80}
81
82static inline void kfree_call_rcu(struct rcu_head *head,
83 void (*func)(struct rcu_head *rcu))
84{
85 call_rcu(head, func);
86}
87
88#ifdef CONFIG_TINY_RCU
89
90static inline void rcu_preempt_note_context_switch(void)
91{
92}
93
94static inline void exit_rcu(void)
95{
96}
97
98static inline int rcu_needs_cpu(int cpu)
99{
100 return 0;
101}
102
103#else /* #ifdef CONFIG_TINY_RCU */
104
105void rcu_preempt_note_context_switch(void);
106extern void exit_rcu(void);
107int rcu_preempt_needs_cpu(void);
108
109static inline int rcu_needs_cpu(int cpu)
110{
111 return rcu_preempt_needs_cpu();
112}
113
114#endif /* #else #ifdef CONFIG_TINY_RCU */
115
116static inline void rcu_note_context_switch(int cpu)
117{
118 rcu_sched_qs(cpu);
119 rcu_preempt_note_context_switch();
120}
121
122/*
123 * Take advantage of the fact that there is only one CPU, which
124 * allows us to ignore virtualization-based context switches.
125 */
126static inline void rcu_virt_note_context_switch(int cpu)
127{
128}
129
130/*
131 * Return the number of grace periods.
132 */
133static inline long rcu_batches_completed(void)
134{
135 return 0;
136}
137
138/*
139 * Return the number of bottom-half grace periods.
140 */
141static inline long rcu_batches_completed_bh(void)
142{
143 return 0;
144}
145
146static inline void rcu_force_quiescent_state(void)
147{
148}
149
150static inline void rcu_bh_force_quiescent_state(void)
151{
152}
153
154static inline void rcu_sched_force_quiescent_state(void)
155{
156}
157
158static inline void rcu_cpu_stall_reset(void)
159{
160}
161
162#ifdef CONFIG_DEBUG_LOCK_ALLOC
163extern int rcu_scheduler_active __read_mostly;
164extern void rcu_scheduler_starting(void);
165#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
166static inline void rcu_scheduler_starting(void)
167{
168}
169#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
170
171#endif /* __LINUX_RCUTINY_H */