1 /* $NetBSD: rcupdate.h,v 1.8 2021/12/19 11:49:11 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2018 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Taylor R. Campbell.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #ifndef _LINUX_RCUPDATE_H_
33 #define _LINUX_RCUPDATE_H_
34
35 #include <sys/atomic.h>
36 #include <sys/cdefs.h>
37 #include <sys/systm.h>
38
39 #include <linux/bug.h>
40
41 #define __rcu
42
43 #define RCU_INIT_POINTER(P, V) ((P) = (V))
44
45 #define rcu_assign_pointer(P,V) atomic_store_release(&(P), (V))
46 #define rcu_dereference(P) atomic_load_consume(&(P))
47 #define rcu_access_pointer(P) atomic_load_relaxed(&(P))
48
49 #define rcu_dereference_raw rcu_dereference
50
51 #define rcu_dereference_protected(P, C) ({ \
52 WARN_ON(!(C)); \
53 (P); \
54 })
55
56 #define rcu_replace_pointer(PTRP, NEWPTR, C) ({ \
57 __typeof__(PTRP) __rrp_ptrp = (PTRP); \
58 __typeof__(PTRP) __rrp_oldptr = \
59 rcu_dereference_protected(__rrp_ptrp, C); \
60 rcu_assign_pointer(__rrp_ptrp, NEWPTR); \
61 __rrp_oldptr; \
62 })
63
64
65 /* kill_dependency */
66 #define rcu_pointer_handoff(P) (P)
67
68 struct rcu_head {
69 union {
70 void (*callback)(struct rcu_head *);
71 void *obj;
72 } rcuh_u;
73 struct rcu_head *rcuh_next;
74 };
75
76 #define _kfree_rcu linux__kfree_rcu
77 #define call_rcu linux_call_rcu
78 #define cond_synchronize_rcu linux_cond_synchronize_rcu
79 #define destroy_rcu_head linux_destroy_rcu_head
80 #define init_rcu_head linux_init_rcu_head
81 #define get_state_synchronize_rcu linux_get_state_synchronize_rcu
82 #define rcu_barrier linux_rcu_barrier
83 #define synchronize_rcu linux_synchronize_rcu
84 #define synchronize_rcu_expedited linux_synchronize_rcu_expedited
85
86 int linux_rcu_gc_init(void);
87 void linux_rcu_gc_fini(void);
88
89 void init_rcu_head(struct rcu_head *);
90 void destroy_rcu_head(struct rcu_head *);
91
92 void call_rcu(struct rcu_head *, void (*)(struct rcu_head *));
93 void rcu_barrier(void);
94 void synchronize_rcu(void);
95 void synchronize_rcu_expedited(void);
96
97 unsigned long get_state_synchronize_rcu(void);
98 void cond_synchronize_rcu(unsigned long);
99
100 void _kfree_rcu(struct rcu_head *, void *);
101
102 static inline void
rcu_read_lock(void)103 rcu_read_lock(void)
104 {
105
106 kpreempt_disable(); /* implies __insn_barrier */
107 }
108
109 static inline void
rcu_read_unlock(void)110 rcu_read_unlock(void)
111 {
112
113 kpreempt_enable(); /* implies __insn_barrier */
114 }
115
116 #define kfree_rcu(P, F) \
117 _kfree_rcu(&(P)->F, (P))
118
119 #endif /* _LINUX_RCUPDATE_H_ */
120