1 #ifndef _LINUX_LIST_H |
|
2 #define _LINUX_LIST_H |
|
3 |
|
4 /* |
|
5 * Simple doubly linked list implementation. |
|
6 * |
|
7 * Some of the internal functions ("__xxx") are useful when |
|
8 * manipulating whole lists rather than single entries, as |
|
9 * sometimes we already know the next/prev entries and we can |
|
10 * generate better code by using them directly rather than |
|
11 * using the generic single-entry routines. |
|
12 */ |
|
13 |
|
14 struct list_head { |
|
15 struct list_head *next, *prev; |
|
16 }; |
|
17 |
|
18 #define LIST_HEAD_INIT(name) { &(name), &(name) } |
|
19 |
|
20 #define LIST_HEAD(name) \ |
|
21 struct list_head name = LIST_HEAD_INIT(name) |
|
22 |
|
23 #define INIT_LIST_HEAD(ptr) do { \ |
|
24 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ |
|
25 } while (0) |
|
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 |
|
34 __list_add(struct list_head *new, |
|
35 struct list_head *prev, 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 |
|
65 list_add_tail(struct list_head *new, struct list_head *head) |
|
66 { |
|
67 __list_add(new, head->prev, head); |
|
68 } |
|
69 |
|
70 /* |
|
71 * Delete a list entry by making the prev/next entries |
|
72 * point to each other. |
|
73 * |
|
74 * This is only for internal list manipulation where we know |
|
75 * the prev/next entries already! |
|
76 */ |
|
77 static inline void |
|
78 __list_del(struct list_head *prev, struct list_head *next) |
|
79 { |
|
80 next->prev = prev; |
|
81 prev->next = next; |
|
82 } |
|
83 |
|
84 /** |
|
85 * list_del - deletes entry from list. |
|
86 * @entry: the element to delete from the list. |
|
87 * Note: list_empty on entry does not return true after this, the entry is |
|
88 * in an undefined state. |
|
89 */ |
|
90 static inline void list_del(struct list_head *entry) |
|
91 { |
|
92 __list_del(entry->prev, entry->next); |
|
93 entry->next = (void *) 0; |
|
94 entry->prev = (void *) 0; |
|
95 } |
|
96 |
|
97 /** |
|
98 * list_del_init - deletes entry from list and reinitialize it. |
|
99 * @entry: the element to delete from the list. |
|
100 */ |
|
101 static inline void list_del_init(struct list_head *entry) |
|
102 { |
|
103 __list_del(entry->prev, entry->next); |
|
104 INIT_LIST_HEAD(entry); |
|
105 } |
|
106 |
|
107 /** |
|
108 * list_move - delete from one list and add as another's head |
|
109 * @list: the entry to move |
|
110 * @head: the head that will precede our entry |
|
111 */ |
|
112 static inline void |
|
113 list_move(struct list_head *list, struct list_head *head) |
|
114 { |
|
115 __list_del(list->prev, list->next); |
|
116 list_add(list, head); |
|
117 } |
|
118 |
|
119 /** |
|
120 * list_move_tail - delete from one list and add as another's tail |
|
121 * @list: the entry to move |
|
122 * @head: the head that will follow our entry |
|
123 */ |
|
124 static inline void |
|
125 list_move_tail(struct list_head *list, struct list_head *head) |
|
126 { |
|
127 __list_del(list->prev, list->next); |
|
128 list_add_tail(list, head); |
|
129 } |
|
130 |
|
131 /** |
|
132 * list_empty - test whether a list is empty |
|
133 * @head: the list to test. |
|
134 */ |
|
135 static inline int list_empty(struct list_head *head) |
|
136 { |
|
137 return head->next == head; |
|
138 } |
|
139 |
|
140 static inline void |
|
141 __list_splice(struct list_head *list, struct list_head *head) |
|
142 { |
|
143 struct list_head *first = list->next; |
|
144 struct list_head *last = list->prev; |
|
145 struct list_head *at = head->next; |
|
146 |
|
147 first->prev = head; |
|
148 head->next = first; |
|
149 |
|
150 last->next = at; |
|
151 at->prev = last; |
|
152 } |
|
153 |
|
154 /** |
|
155 * list_splice - join two lists |
|
156 * @list: the new list to add. |
|
157 * @head: the place to add it in the first list. |
|
158 */ |
|
159 static inline void |
|
160 list_splice(struct list_head *list, struct list_head *head) |
|
161 { |
|
162 if (!list_empty(list)) |
|
163 __list_splice(list, head); |
|
164 } |
|
165 |
|
166 /** |
|
167 * list_splice_init - join two lists and reinitialise the emptied list. |
|
168 * @list: the new list to add. |
|
169 * @head: the place to add it in the first list. |
|
170 * |
|
171 * The list at @list is reinitialised |
|
172 */ |
|
173 static inline void |
|
174 list_splice_init(struct list_head *list, struct list_head *head) |
|
175 { |
|
176 if (!list_empty(list)) { |
|
177 __list_splice(list, head); |
|
178 INIT_LIST_HEAD(list); |
|
179 } |
|
180 } |
|
181 |
|
182 /** |
|
183 * list_entry - get the struct for this entry |
|
184 * @ptr: the &struct list_head pointer. |
|
185 * @type: the type of the struct this is embedded in. |
|
186 * @member: the name of the list_struct within the struct. |
|
187 */ |
|
188 #define list_entry(ptr, type, member) \ |
|
189 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) |
|
190 |
|
191 /** |
|
192 * list_for_each_safe - iterate over a list safe against removal of list entry |
|
193 * @pos: the &struct list_head to use as a loop counter. |
|
194 * @n: another &struct list_head to use as temporary storage |
|
195 * @head: the head for your list. |
|
196 */ |
|
197 #define list_for_each_safe(pos, n, head) \ |
|
198 for (pos = (head)->next, n = pos->next; pos != (head); \ |
|
199 pos = n, n = pos->next) |
|
200 |
|
201 /** |
|
202 * list_for_each_entry_safe - iterate over list of given type safe against |
|
203 * removal of list entry |
|
204 * @pos: the type * to use as a loop counter. |
|
205 * @n: another type * to use as temporary storage |
|
206 * @head: the head for your list. |
|
207 * @member: the name of the list_struct within the struct. |
|
208 */ |
|
209 #define list_for_each_entry_safe(pos, n, head, member) \ |
|
210 for (pos = list_entry((head)->next, typeof(*pos), member), \ |
|
211 n = list_entry(pos->member.next, typeof(*pos), member); \ |
|
212 &pos->member != (head); \ |
|
213 pos = n, n = list_entry(n->member.next, typeof(*n), member)) |
|
214 |
|
215 #endif |
|