2 * Copyright (C) 2002 Free Software Foundation, Inc.
3 * (originally part of the GNU C Library and Userspace RCU)
4 * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
6 * Copyright (C) 2009 Pierre-Marc Fournier
7 * Conversion to RCU list.
8 * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with this library; if not, see
22 * <http://www.gnu.org/licenses/>.
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.
34 /* Basic type for the double-link list. */
36 struct list_head
*next
, *prev
;
39 /* Define a variable with the head and tail of the list. */
40 #define LIST_HEAD(name) \
41 struct list_head name = { &(name), &(name) }
43 /* Initialize a new list head. */
44 #define INIT_LIST_HEAD(ptr) \
45 (ptr)->next = (ptr)->prev = (ptr)
47 #define LIST_HEAD_INIT(name) { &(name), &(name) }
49 /* Add new element at the head of the list. */
50 static inline void list_add(struct list_head
*newp
, struct list_head
*head
)
52 head
->next
->prev
= newp
;
53 newp
->next
= head
->next
;
58 /* Add new element at the tail of the list. */
59 static inline void list_add_tail(struct list_head
*newp
, struct list_head
*head
)
61 head
->prev
->next
= newp
;
63 newp
->prev
= head
->prev
;
67 /* Remove element from list. */
68 static inline void __list_del(struct list_head
*prev
, struct list_head
*next
)
74 /* Remove element from list. */
75 static inline void list_del(struct list_head
*elem
)
77 __list_del(elem
->prev
, elem
->next
);
80 /* Remove element from list, initializing the element's list pointers. */
81 static inline void list_del_init(struct list_head
*elem
)
87 /* Delete from list, add to another list as head. */
88 static inline void list_move(struct list_head
*elem
, struct list_head
*head
)
90 __list_del(elem
->prev
, elem
->next
);
94 /* Replace an old entry. */
95 static inline void list_replace(struct list_head
*old
, struct list_head
*newp
)
97 newp
->next
= old
->next
;
98 newp
->prev
= old
->prev
;
99 newp
->prev
->next
= newp
;
100 newp
->next
->prev
= newp
;
103 /* Join two lists. */
104 static inline void list_splice(struct list_head
*add
, struct list_head
*head
)
106 /* Do nothing if the list which gets added is empty. */
107 if (add
!= add
->next
) {
108 add
->next
->prev
= head
;
109 add
->prev
->next
= head
->next
;
110 head
->next
->prev
= add
->prev
;
111 head
->next
= add
->next
;
115 /* Get typed element from list at a given position. */
116 #define list_entry(ptr, type, member) \
117 ((type *) ((char *) (ptr) - offsetof(type, member)))
119 /* Get first entry from a list. */
120 #define list_first_entry(ptr, type, member) \
121 list_entry((ptr)->next, type, member)
123 /* Iterate forward over the elements of the list. */
124 #define list_for_each(pos, head) \
125 for (pos = (head)->next; pos != (head); pos = pos->next)
128 * Iterate forward over the elements list. The list elements can be
129 * removed from the list while doing this.
131 #define list_for_each_safe(pos, p, head) \
132 for (pos = (head)->next, p = pos->next; \
134 pos = p, p = pos->next)
136 /* Iterate backward over the elements of the list. */
137 #define list_for_each_prev(pos, head) \
138 for (pos = (head)->prev; pos != (head); pos = pos->prev)
141 * Iterate backwards over the elements list. The list elements can be
142 * removed from the list while doing this.
144 #define list_for_each_prev_safe(pos, p, head) \
145 for (pos = (head)->prev, p = pos->prev; \
147 pos = p, p = pos->prev)
149 static inline int list_empty(struct list_head
*head
)
151 return head
== head
->next
;
154 static inline void list_replace_init(struct list_head
*old
,
155 struct list_head
*newp
)
157 struct list_head
*head
= old
->next
;
160 list_add_tail(newp
, head
);