1 /* $NetBSD: llist.h,v 1.7 2022/04/09 23:43:55 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_LLIST_H_
33 #define _LINUX_LLIST_H_
34
35 #include <sys/atomic.h>
36 #include <sys/null.h>
37
38 struct llist_head {
39 struct llist_node *first;
40 };
41
42 struct llist_node {
43 struct llist_node *next;
44 };
45
46 static inline void
init_llist_head(struct llist_head * head)47 init_llist_head(struct llist_head *head)
48 {
49
50 head->first = NULL;
51 }
52
53 #define llist_entry(NODE, TYPE, FIELD) container_of(NODE, TYPE, FIELD)
54
55 static inline bool
llist_empty(struct llist_head * head)56 llist_empty(struct llist_head *head)
57 {
58 bool empty;
59
60 empty = (atomic_load_acquire(&head->first) == NULL);
61
62 return empty;
63 }
64
65 static inline bool
llist_add(struct llist_node * node,struct llist_head * head)66 llist_add(struct llist_node *node, struct llist_head *head)
67 {
68 struct llist_node *first;
69
70 do {
71 first = head->first;
72 node->next = first;
73 membar_release();
74 } while (atomic_cas_ptr(&head->first, first, node) != first);
75
76 return first == NULL;
77 }
78
79 static inline bool
llist_add_batch(struct llist_node * first,struct llist_node * last,struct llist_head * head)80 llist_add_batch(struct llist_node *first, struct llist_node *last,
81 struct llist_head *head)
82 {
83 struct llist_node *next;
84
85 do {
86 next = atomic_load_consume(&head->first);
87 last->next = next;
88 } while (atomic_cas_ptr(&head->first, next, first) != next);
89
90 return next == NULL;
91 }
92
93 static inline struct llist_node *
llist_del_all(struct llist_head * head)94 llist_del_all(struct llist_head *head)
95 {
96 struct llist_node *first;
97
98 first = atomic_swap_ptr(&head->first, NULL);
99 membar_datadep_consumer();
100
101 return first;
102 }
103
104 static inline struct llist_node *
llist_del_first(struct llist_head * head)105 llist_del_first(struct llist_head *head)
106 {
107 struct llist_node *first;
108
109 do {
110 first = atomic_load_consume(&head->first);
111 if (first == NULL)
112 return NULL;
113 } while (atomic_cas_ptr(&head->first, first, first->next)
114 != first);
115
116 return first;
117 }
118
119 #define _llist_next(ENTRY, FIELD) \
120 ({ \
121 __typeof__((ENTRY)->FIELD.next) _NODE = \
122 atomic_load_consume(&(ENTRY)->FIELD.next); \
123 (_NODE == NULL ? NULL : \
124 llist_entry(_NODE, __typeof__(*(ENTRY)), FIELD)); \
125 })
126
127 #define llist_for_each_safe(NODE, TMP, HEAD) \
128 for ((NODE) = (HEAD); \
129 (NODE) && ((TMP) = (NODE)->next, 1); \
130 (NODE) = (TMP))
131
132 #define llist_for_each_entry(ENTRY, NODE, FIELD) \
133 for ((ENTRY) = ((NODE) == NULL ? NULL : \
134 (membar_datadep_consumer(), \
135 llist_entry(NODE, typeof(*(ENTRY)), FIELD))); \
136 (ENTRY) != NULL; \
137 (ENTRY) = _llist_next(ENTRY, FIELD))
138
139 #define llist_for_each_entry_safe(ENTRY, TMP, NODE, FIELD) \
140 for ((ENTRY) = ((NODE) == NULL ? NULL : \
141 (membar_datadep_consumer(), \
142 llist_entry(NODE, typeof(*(ENTRY)), FIELD))); \
143 ((ENTRY) == NULL ? 0 : \
144 ((TMP) = _llist_next(ENTRY, FIELD), 1)); \
145 (ENTRY) = (TMP))
146
147 #endif /* _LINUX_LLIST_H_ */
148