Commit | Line | Data |
---|---|---|
63eba147 JA |
1 | #ifndef _LINUX_LIST_H |
2 | #define _LINUX_LIST_H | |
3 | ||
4 | /* | |
5 | * These are non-NULL pointers that will result in page faults | |
6 | * under normal circumstances, used to verify that nobody uses | |
7 | * non-initialized list entries. | |
8 | */ | |
9 | #define LIST_POISON1 ((void *) 0x00100100) | |
10 | #define LIST_POISON2 ((void *) 0x00200200) | |
11 | ||
12 | struct list_head { | |
13 | struct list_head *next, *prev; | |
14 | }; | |
15 | ||
16 | #define LIST_HEAD_INIT(name) { &(name), &(name) } | |
17 | ||
18 | #define LIST_HEAD(name) \ | |
19 | struct list_head name = LIST_HEAD_INIT(name) | |
20 | ||
21 | static inline void INIT_LIST_HEAD(struct list_head *list) | |
22 | { | |
23 | list->next = list; | |
24 | list->prev = list; | |
25 | } | |
26 | ||
27 | /* | |
28 | * Insert a new entry between two known consecutive entries. | |
29 | * | |
30 | * This is only for internal list manipulation where we know | |
31 | * the prev/next entries already! | |
32 | */ | |
33 | static inline void __list_add(struct list_head *new, | |
34 | struct list_head *prev, | |
35 | struct list_head *next) | |
36 | { | |
37 | next->prev = new; | |
38 | new->next = next; | |
39 | new->prev = prev; | |
40 | prev->next = new; | |
41 | } | |
42 | ||
43 | /** | |
44 | * list_add - add a new entry | |
45 | * @new: new entry to be added | |
46 | * @head: list head to add it after | |
47 | * | |
48 | * Insert a new entry after the specified head. | |
49 | * This is good for implementing stacks. | |
50 | */ | |
51 | static inline void list_add(struct list_head *new, struct list_head *head) | |
52 | { | |
53 | __list_add(new, head, head->next); | |
54 | } | |
55 | ||
56 | /** | |
57 | * list_add_tail - add a new entry | |
58 | * @new: new entry to be added | |
59 | * @head: list head to add it before | |
60 | * | |
61 | * Insert a new entry before the specified head. | |
62 | * This is useful for implementing queues. | |
63 | */ | |
64 | static inline void list_add_tail(struct list_head *new, struct list_head *head) | |
65 | { | |
66 | __list_add(new, head->prev, head); | |
67 | } | |
68 | ||
69 | /* | |
70 | * Delete a list entry by making the prev/next entries | |
71 | * point to each other. | |
72 | * | |
73 | * This is only for internal list manipulation where we know | |
74 | * the prev/next entries already! | |
75 | */ | |
76 | static inline void __list_del(struct list_head * prev, struct list_head * next) | |
77 | { | |
78 | next->prev = prev; | |
79 | prev->next = next; | |
80 | } | |
81 | ||
82 | /** | |
83 | * list_del - deletes entry from list. | |
84 | * @entry: the element to delete from the list. | |
85 | * Note: list_empty on entry does not return true after this, the entry is | |
86 | * in an undefined state. | |
87 | */ | |
88 | static inline void list_del(struct list_head *entry) | |
89 | { | |
90 | __list_del(entry->prev, entry->next); | |
91 | entry->next = LIST_POISON1; | |
92 | entry->prev = LIST_POISON2; | |
93 | } | |
94 | ||
95 | /** | |
96 | * __list_for_each - iterate over a list | |
97 | * @pos: the &struct list_head to use as a loop counter. | |
98 | * @head: the head for your list. | |
99 | * | |
100 | * This variant differs from list_for_each() in that it's the | |
101 | * simplest possible list iteration code, no prefetching is done. | |
102 | * Use this for code that knows the list to be very short (empty | |
103 | * or 1 entry) most of the time. | |
104 | */ | |
105 | #define __list_for_each(pos, head) \ | |
106 | for (pos = (head)->next; pos != (head); pos = pos->next) | |
107 | ||
108 | /** | |
109 | * list_for_each_safe - iterate over a list safe against removal of list entry | |
110 | * @pos: the &struct list_head to use as a loop counter. | |
111 | * @n: another &struct list_head to use as temporary storage | |
112 | * @head: the head for your list. | |
113 | */ | |
114 | #define list_for_each_safe(pos, n, head) \ | |
115 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
116 | pos = n, n = pos->next) | |
117 | ||
118 | /** | |
119 | * list_entry - get the struct for this entry | |
120 | * @ptr: the &struct list_head pointer. | |
121 | * @type: the type of the struct this is embedded in. | |
122 | * @member: the name of the list_struct within the struct. | |
123 | */ | |
124 | #define list_entry(ptr, type, member) \ | |
125 | container_of(ptr, type, member) | |
126 | ||
127 | static inline int list_len(struct list_head *head_p) | |
128 | { | |
129 | struct list_head *p; | |
130 | int n = 0; | |
131 | ||
132 | __list_for_each(p, head_p) { | |
133 | n++; | |
134 | } | |
135 | ||
136 | return n; | |
137 | } | |
138 | ||
139 | /** | |
140 | * list_empty - tests whether a list is empty | |
141 | * @head: the list to test. | |
142 | */ | |
143 | static inline int list_empty(const struct list_head *head) | |
144 | { | |
145 | return head->next == head; | |
146 | } | |
147 | ||
095181f2 JA |
148 | /** |
149 | * list_first - Returns first entry on list, or NULL if empty | |
150 | * @head: the list | |
151 | */ | |
152 | static inline struct list_head *list_first(const struct list_head *head) | |
153 | { | |
154 | return list_empty(head) ? NULL : head->next; | |
155 | } | |
156 | ||
157 | /** | |
158 | * list_move_tail - delete from one list and add as another's tail | |
159 | * @list: the entry to move | |
160 | * @head: the head that will follow our entry | |
161 | */ | |
162 | static inline void list_move_tail(struct list_head *list, | |
163 | struct list_head *head) | |
164 | { | |
165 | __list_del(list->prev, list->next); | |
166 | list_add_tail(list, head); | |
167 | } | |
168 | ||
63eba147 | 169 | #endif |