1 /*
2 * Copyright (c) 2017-2020 François Tigeot <ftigeot@wolfpond.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #ifndef _LINUX_RCUPDATE_H_
28 #define _LINUX_RCUPDATE_H_
29
30 #include <linux/types.h>
31 #include <linux/cache.h>
32 #include <linux/spinlock.h>
33 #include <linux/threads.h>
34 #include <linux/cpumask.h>
35 #include <linux/seqlock.h>
36 #include <linux/lockdep.h>
37 #include <linux/completion.h>
38 #include <linux/bug.h>
39 #include <linux/compiler.h>
40 #include <linux/ktime.h>
41
42 #include <asm/barrier.h>
43
44 #include <linux/rcutree.h>
45
46 static inline void
rcu_read_lock(void)47 rcu_read_lock(void)
48 {
49 preempt_disable();
50 }
51
52 static inline void
rcu_read_unlock(void)53 rcu_read_unlock(void)
54 {
55 preempt_enable();
56 }
57
58 #define rcu_dereference_protected(p, condition) \
59 ((typeof(*p) *)(p))
60
61 #define rcu_dereference(p) \
62 ({ \
63 typeof(*(p)) *__rcu_dereference_tmp = READ_ONCE(p); \
64 __rcu_dereference_tmp; \
65 })
66
67 #define rcu_dereference_raw(p) \
68 ((__typeof(*p) *)READ_ONCE(p))
69
70 #define rcu_assign_pointer(p, v) \
71 do { \
72 cpu_mfence(); \
73 WRITE_ONCE((p), (v)); \
74 } while (0)
75
76 #define RCU_INIT_POINTER(p, v) \
77 do { \
78 p = v; \
79 } while (0)
80
81 extern void __kfree_rcu(void *ptr);
82
83 #define kfree_rcu(ptr, rcu_head) \
84 do { \
85 __kfree_rcu(ptr); \
86 } while (0)
87
88 extern void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *));
89
90 #define rcu_access_pointer(p) ((typeof(*p) *)READ_ONCE(p))
91
92 #define rcu_pointer_handoff(p) (p)
93
94 #define synchronize_rcu()
95
96 #endif /* _LINUX_RCUPDATE_H_ */
97