Fix: handle sys_futex() FUTEX_WAIT interrupted by signal
[urcu.git] / urcu / list.h
1 /*
2 * Copyright (C) 2002 Free Software Foundation, Inc.
3 * (originally part of the GNU C Library)
4 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
5 *
6 * Copyright (C) 2009 Pierre-Marc Fournier
7 * Conversion to RCU list.
8 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 *
10 * This library is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with this library; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #ifndef _CDS_LIST_H
26 #define _CDS_LIST_H 1
27
28 /*
29 * The definitions of this file are adopted from those which can be
30 * found in the Linux kernel headers to enable people familiar with the
31 * latter find their way in these sources as well.
32 */
33
34 /* Basic type for the double-link list. */
35 struct cds_list_head {
36 struct cds_list_head *next, *prev;
37 };
38
39 /* Define a variable with the head and tail of the list. */
40 #define CDS_LIST_HEAD(name) \
41 struct cds_list_head name = { &(name), &(name) }
42
43 /* Initialize a new list head. */
44 #define CDS_INIT_LIST_HEAD(ptr) \
45 (ptr)->next = (ptr)->prev = (ptr)
46
47 #define CDS_LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
48
49 /* Add new element at the head of the list. */
50 static inline
51 void cds_list_add(struct cds_list_head *newp, struct cds_list_head *head)
52 {
53 head->next->prev = newp;
54 newp->next = head->next;
55 newp->prev = head;
56 head->next = newp;
57 }
58
59 /* Add new element at the tail of the list. */
60 static inline
61 void cds_list_add_tail(struct cds_list_head *newp, struct cds_list_head *head)
62 {
63 head->prev->next = newp;
64 newp->next = head;
65 newp->prev = head->prev;
66 head->prev = newp;
67 }
68
69 /* Remove element from list. */
70 static inline
71 void __cds_list_del(struct cds_list_head *prev, struct cds_list_head *next)
72 {
73 next->prev = prev;
74 prev->next = next;
75 }
76
77 /* Remove element from list. */
78 static inline
79 void cds_list_del(struct cds_list_head *elem)
80 {
81 __cds_list_del(elem->prev, elem->next);
82 }
83
84 /* Remove element from list, initializing the element's list pointers. */
85 static inline
86 void cds_list_del_init(struct cds_list_head *elem)
87 {
88 cds_list_del(elem);
89 CDS_INIT_LIST_HEAD(elem);
90 }
91
92 /* Delete from list, add to another list as head. */
93 static inline
94 void cds_list_move(struct cds_list_head *elem, struct cds_list_head *head)
95 {
96 __cds_list_del(elem->prev, elem->next);
97 cds_list_add(elem, head);
98 }
99
100 /* Replace an old entry. */
101 static inline
102 void cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
103 {
104 _new->next = old->next;
105 _new->prev = old->prev;
106 _new->prev->next = _new;
107 _new->next->prev = _new;
108 }
109
110 /* Join two lists. */
111 static inline
112 void cds_list_splice(struct cds_list_head *add, struct cds_list_head *head)
113 {
114 /* Do nothing if the list which gets added is empty. */
115 if (add != add->next) {
116 add->next->prev = head;
117 add->prev->next = head->next;
118 head->next->prev = add->prev;
119 head->next = add->next;
120 }
121 }
122
123 /* Get typed element from list at a given position. */
124 #define cds_list_entry(ptr, type, member) \
125 ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
126
127
128 /* Get first entry from a list. */
129 #define cds_list_first_entry(ptr, type, member) \
130 cds_list_entry((ptr)->next, type, member)
131
132 /* Iterate forward over the elements of the list. */
133 #define cds_list_for_each(pos, head) \
134 for (pos = (head)->next; pos != (head); pos = pos->next)
135
136 /*
137 * Iterate forward over the elements list. The list elements can be
138 * removed from the list while doing this.
139 */
140 #define cds_list_for_each_safe(pos, p, head) \
141 for (pos = (head)->next, p = pos->next; \
142 pos != (head); \
143 pos = p, p = pos->next)
144
145 /* Iterate backward over the elements of the list. */
146 #define cds_list_for_each_prev(pos, head) \
147 for (pos = (head)->prev; pos != (head); pos = pos->prev)
148
149 /*
150 * Iterate backwards over the elements list. The list elements can be
151 * removed from the list while doing this.
152 */
153 #define cds_list_for_each_prev_safe(pos, p, head) \
154 for (pos = (head)->prev, p = pos->prev; \
155 pos != (head); \
156 pos = p, p = pos->prev)
157
158 #define cds_list_for_each_entry(pos, head, member) \
159 for (pos = cds_list_entry((head)->next, __typeof__(*pos), member); \
160 &pos->member != (head); \
161 pos = cds_list_entry(pos->member.next, __typeof__(*pos), member))
162
163 #define cds_list_for_each_entry_reverse(pos, head, member) \
164 for (pos = cds_list_entry((head)->prev, __typeof__(*pos), member); \
165 &pos->member != (head); \
166 pos = cds_list_entry(pos->member.prev, __typeof__(*pos), member))
167
168 #define cds_list_for_each_entry_safe(pos, p, head, member) \
169 for (pos = cds_list_entry((head)->next, __typeof__(*pos), member), \
170 p = cds_list_entry(pos->member.next, __typeof__(*pos), member); \
171 &pos->member != (head); \
172 pos = p, p = cds_list_entry(pos->member.next, __typeof__(*pos), member))
173
174 /*
175 * Same as cds_list_for_each_entry_safe, but starts from "pos" which should
176 * point to an entry within the list.
177 */
178 #define cds_list_for_each_entry_safe_from(pos, p, head, member) \
179 for (p = cds_list_entry(pos->member.next, __typeof__(*pos), member); \
180 &pos->member != (head); \
181 pos = p, p = cds_list_entry(pos->member.next, __typeof__(*pos), member))
182
183 static inline
184 int cds_list_empty(struct cds_list_head *head)
185 {
186 return head == head->next;
187 }
188
189 static inline
190 void cds_list_replace_init(struct cds_list_head *old,
191 struct cds_list_head *_new)
192 {
193 struct cds_list_head *head = old->next;
194
195 cds_list_del(old);
196 cds_list_add_tail(_new, head);
197 CDS_INIT_LIST_HEAD(old);
198 }
199
200 #endif /* _CDS_LIST_H */
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