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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 __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 in an undefined state. | |
86 | */ | |
87 | static inline void list_del(struct list_head *entry) | |
88 | { | |
89 | __list_del(entry->prev, entry->next); | |
90 | entry->next = (void *) 0; | |
91 | entry->prev = (void *) 0; | |
92 | } | |
93 | ||
94 | /** | |
95 | * list_del_init - deletes entry from list and reinitialize it. | |
96 | * @entry: the element to delete from the list. | |
97 | */ | |
98 | static inline void list_del_init(struct list_head *entry) | |
99 | { | |
100 | __list_del(entry->prev, entry->next); | |
101 | INIT_LIST_HEAD(entry); | |
102 | } | |
103 | ||
104 | /** | |
105 | * list_move - delete from one list and add as another's head | |
106 | * @list: the entry to move | |
107 | * @head: the head that will precede our entry | |
108 | */ | |
109 | static inline void list_move(struct list_head *list, struct list_head *head) | |
110 | { | |
111 | __list_del(list->prev, list->next); | |
112 | list_add(list, head); | |
113 | } | |
114 | ||
115 | /** | |
116 | * list_move_tail - delete from one list and add as another's tail | |
117 | * @list: the entry to move | |
118 | * @head: the head that will follow our entry | |
119 | */ | |
120 | static inline void list_move_tail(struct list_head *list, | |
121 | struct list_head *head) | |
122 | { | |
123 | __list_del(list->prev, list->next); | |
124 | list_add_tail(list, head); | |
125 | } | |
126 | ||
127 | /** | |
128 | * list_empty - tests whether a list is empty | |
129 | * @head: the list to test. | |
130 | */ | |
131 | static inline int list_empty(struct list_head *head) | |
132 | { | |
133 | return head->next == head; | |
134 | } | |
135 | ||
136 | static inline void __list_splice(struct list_head *list, | |
137 | struct list_head *head) | |
138 | { | |
139 | struct list_head *first = list->next; | |
140 | struct list_head *last = list->prev; | |
141 | struct list_head *at = head->next; | |
142 | ||
143 | first->prev = head; | |
144 | head->next = first; | |
145 | ||
146 | last->next = at; | |
147 | at->prev = last; | |
148 | } | |
149 | ||
150 | /** | |
151 | * list_splice - join two lists | |
152 | * @list: the new list to add. | |
153 | * @head: the place to add it in the first list. | |
154 | */ | |
155 | static inline void list_splice(struct list_head *list, struct list_head *head) | |
156 | { | |
157 | if (!list_empty(list)) | |
158 | __list_splice(list, head); | |
159 | } | |
160 | ||
161 | /** | |
162 | * list_splice_init - join two lists and reinitialise the emptied list. | |
163 | * @list: the new list to add. | |
164 | * @head: the place to add it in the first list. | |
165 | * | |
166 | * The list at @list is reinitialised | |
167 | */ | |
168 | static inline void list_splice_init(struct list_head *list, | |
169 | struct list_head *head) | |
170 | { | |
171 | if (!list_empty(list)) { | |
172 | __list_splice(list, head); | |
173 | INIT_LIST_HEAD(list); | |
174 | } | |
175 | } | |
176 | ||
177 | /** | |
178 | * list_entry - get the struct for this entry | |
179 | * @ptr: the &struct list_head pointer. | |
180 | * @type: the type of the struct this is embedded in. | |
181 | * @member: the name of the list_struct within the struct. | |
182 | */ | |
183 | #define list_entry(ptr, type, member) \ | |
184 | ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) | |
185 | ||
186 | /** | |
187 | * list_for_each - iterate over a list | |
188 | * @pos: the &struct list_head to use as a loop counter. | |
189 | * @head: the head for your list. | |
190 | */ | |
191 | #define list_for_each(pos, head) \ | |
192 | for (pos = (head)->next; pos != (head); \ | |
193 | pos = pos->next) | |
194 | /** | |
195 | * list_for_each_prev - iterate over a list backwards | |
196 | * @pos: the &struct list_head to use as a loop counter. | |
197 | * @head: the head for your list. | |
198 | */ | |
199 | #define list_for_each_prev(pos, head) \ | |
200 | for (pos = (head)->prev; pos != (head); \ | |
201 | pos = pos->prev) | |
202 | ||
203 | /** | |
204 | * list_for_each_safe - iterate over a list safe against removal of list entry | |
205 | * @pos: the &struct list_head to use as a loop counter. | |
206 | * @n: another &struct list_head to use as temporary storage | |
207 | * @head: the head for your list. | |
208 | */ | |
209 | #define list_for_each_safe(pos, n, head) \ | |
210 | for (pos = (head)->next, n = pos->next; pos != (head); \ | |
211 | pos = n, n = pos->next) | |
212 | ||
213 | /** | |
214 | * list_for_each_entry - iterate over list of given type | |
215 | * @pos: the type * to use as a loop counter. | |
216 | * @head: the head for your list. | |
217 | * @member: the name of the list_struct within the struct. | |
8fb8959f | 218 | * @type: the type of the struct. |
b089cc9f | 219 | */ |
8fb8959f | 220 | #define list_for_each_entry(pos, head, member, type) \ |
221 | for (pos = list_entry((head)->next, type, member); \ | |
b089cc9f | 222 | &pos->member != (head); \ |
8fb8959f | 223 | pos = list_entry(pos->member.next, type, member)) |
b089cc9f LJ |
224 | |
225 | /** | |
226 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry | |
227 | * @pos: the type * to use as a loop counter. | |
228 | * @n: another type * to use as temporary storage | |
229 | * @head: the head for your list. | |
230 | * @member: the name of the list_struct within the struct. | |
8fb8959f | 231 | * @type: the type of the struct. |
b089cc9f | 232 | */ |
8fb8959f | 233 | #define list_for_each_entry_safe(pos, n, head, member, type) \ |
234 | for (pos = list_entry((head)->next, type, member), \ | |
235 | n = list_entry(pos->member.next, type, member); \ | |
b089cc9f | 236 | &pos->member != (head); \ |
8fb8959f | 237 | pos = n, n = list_entry(n->member.next, type, member)) |
b089cc9f LJ |
238 | |
239 | /** | |
240 | * list_for_each_entry_continue - iterate over list of given type | |
241 | * continuing after existing point | |
242 | * @pos: the type * to use as a loop counter. | |
243 | * @head: the head for your list. | |
244 | * @member: the name of the list_struct within the struct. | |
8fb8959f | 245 | * @type: the type of the struct. |
b089cc9f | 246 | */ |
8fb8959f | 247 | #define list_for_each_entry_continue(pos, head, member, type) \ |
248 | for (pos = list_entry(pos->member.next, type, member), \ | |
b089cc9f LJ |
249 | prefetch(pos->member.next); \ |
250 | &pos->member != (head); \ | |
8fb8959f | 251 | pos = list_entry(pos->member.next, type, member), \ |
b089cc9f LJ |
252 | prefetch(pos->member.next)) |
253 | ||
254 | #endif |