Makefile.in: switch from git-tar-tree to git-archive
[paraslash.git] / list.h
1 /*
2 * Copied from the Linux kernel source tree, version 2.6.13.
3 *
4 * Licensed under the GPL v2 as per the whole kernel source tree.
5 *
6 */
7
8 #include <stddef.h> /* offsetof */
9 #ifndef _LINUX_LIST_H
10 #define _LINUX_LIST_H
11
12 #define container_of(ptr, type, member) ({ \
13 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
14 (type *)( (char *)__mptr - offsetof(type,member) );})
15
16 /*
17 * These are non-NULL pointers that will result in page faults
18 * under normal circumstances, used to verify that nobody uses
19 * non-initialized list entries.
20 */
21 #define LIST_POISON1 ((void *) 0x00100100)
22 #define LIST_POISON2 ((void *) 0x00200200)
23
24 /*
25 * Simple doubly linked list implementation.
26 *
27 * Some of the internal functions ("__xxx") are useful when
28 * manipulating whole lists rather than single entries, as
29 * sometimes we already know the next/prev entries and we can
30 * generate better code by using them directly rather than
31 * using the generic single-entry routines.
32 */
33
34 struct list_head {
35 struct list_head *next, *prev;
36 };
37
38 #define INIT_LIST_HEAD(ptr) do { \
39 (ptr)->next = (ptr); (ptr)->prev = (ptr); \
40 } while (0)
41
42 /*
43 * Insert a new entry between two known consecutive entries.
44 *
45 * This is only for internal list manipulation where we know
46 * the prev/next entries already!
47 */
48 static inline void __list_add(struct list_head *new,
49 struct list_head *prev,
50 struct list_head *next)
51 {
52 next->prev = new;
53 new->next = next;
54 new->prev = prev;
55 prev->next = new;
56 }
57
58 /**
59 * add a new entry
60 *
61 * \param new: new entry to be added
62 * \param head: list head to add it after
63 *
64 * Insert a new entry after the specified head.
65 * This is good for implementing stacks.
66 */
67 static inline void para_list_add(struct list_head *new, struct list_head *head)
68 {
69 __list_add(new, head, head->next);
70 }
71
72 /**
73 * list_add_tail - add a new entry
74 * @new: new entry to be added
75 * @head: list head to add it before
76 *
77 * Insert a new entry before the specified head.
78 * This is useful for implementing queues.
79 */
80 static inline void list_add_tail(struct list_head *new, struct list_head *head)
81 {
82 __list_add(new, head->prev, head);
83 }
84
85 /*
86 * Delete a list entry by making the prev/next entries
87 * point to each other.
88 *
89 * This is only for internal list manipulation where we know
90 * the prev/next entries already!
91 */
92 static inline void __list_del(struct list_head * prev, struct list_head * next)
93 {
94 next->prev = prev;
95 prev->next = next;
96 }
97
98 /**
99 * list_del - deletes entry from list.
100 * @entry: the element to delete from the list.
101 * Note: list_empty on entry does not return true after this, the entry is
102 * in an undefined state.
103 */
104 static inline void list_del(struct list_head *entry)
105 {
106 __list_del(entry->prev, entry->next);
107 entry->next = LIST_POISON1;
108 entry->prev = LIST_POISON2;
109 }
110
111 /**
112 * list_move - delete from one list and add as another's head
113 * @list: the entry to move
114 * @head: the head that will precede our entry
115 */
116 static inline void list_move(struct list_head *list, struct list_head *head)
117 {
118 __list_del(list->prev, list->next);
119 para_list_add(list, head);
120 }
121
122 /**
123 * list_empty - tests whether a list is empty
124 * @head: the list to test.
125 */
126 static inline int list_empty(const struct list_head *head)
127 {
128 return head->next == head;
129 }
130
131 /**
132 * list_entry - get the struct for this entry
133 * @ptr: the &struct list_head pointer.
134 * @type: the type of the struct this is embedded in.
135 * @member: the name of the list_struct within the struct.
136 */
137 #define list_entry(ptr, type, member) \
138 container_of(ptr, type, member)
139
140 /**
141 * list_for_each_safe - iterate over a list safe against removal of list entry
142 * @pos: the &struct list_head to use as a loop counter.
143 * @n: another &struct list_head to use as temporary storage
144 * @head: the head for your list.
145 */
146 #define list_for_each_safe(pos, n, head) \
147 for (pos = (head)->next, n = pos->next; pos != (head); \
148 pos = n, n = pos->next)
149
150 /**
151 * list_for_each_entry - iterate over list of given type
152 * @pos: the type * to use as a loop counter.
153 * @head: the head for your list.
154 * @member: the name of the list_struct within the struct.
155 */
156 #define list_for_each_entry(pos, head, member) \
157 for (pos = list_entry((head)->next, typeof(*pos), member); \
158 &pos->member != (head); \
159 pos = list_entry(pos->member.next, typeof(*pos), member))
160
161 /**
162 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
163 * @pos: the type * to use as a loop counter.
164 * @n: another type * to use as temporary storage
165 * @head: the head for your list.
166 * @member: the name of the list_struct within the struct.
167 */
168 #define list_for_each_entry_safe(pos, n, head, member) \
169 for (pos = list_entry((head)->next, typeof(*pos), member), \
170 n = list_entry(pos->member.next, typeof(*pos), member); \
171 &pos->member != (head); \
172 pos = n, n = list_entry(n->member.next, typeof(*n), member))
173 /**
174 * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against
175 * removal of list entry
176 * @pos: the type * to use as a loop counter.
177 * @n: another type * to use as temporary storage
178 * @head: the head for your list.
179 * @member: the name of the list_struct within the struct.
180 */
181 #define list_for_each_entry_safe_reverse(pos, n, head, member) \
182 for (pos = list_entry((head)->prev, typeof(*pos), member), \
183 n = list_entry(pos->member.prev, typeof(*pos), member); \
184 &pos->member != (head); \
185 pos = n, n = list_entry(n->member.prev, typeof(*n), member))
186
187 #endif /* _LIST_H */