4 /* This file is from Linux Kernel (include/linux/list.h)
5 * and modified by simply removing hardware prefetching of list items.
6 * Here by copyright, credits attributed to wherever they belong.
7 * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
11 * Simple doubly linked list implementation.
13 * Some of the internal functions ("__xxx") are useful when
14 * manipulating whole lists rather than single entries, as
15 * sometimes we already know the next/prev entries and we can
16 * generate better code by using them directly rather than
17 * using the generic single-entry routines.
21 struct list_head
*next
, *prev
;
24 #define LIST_HEAD_INIT(name) { &(name), &(name) }
26 #define LIST_HEAD(name) \
27 struct list_head name = LIST_HEAD_INIT(name)
29 #define INIT_LIST_HEAD(ptr) do { \
30 (ptr)->next = (ptr); (ptr)->prev = (ptr); \
34 * Insert a new entry between two known consecutive entries.
36 * This is only for internal list manipulation where we know
37 * the prev/next entries already!
39 static inline void __list_add(struct list_head
*new,
40 struct list_head
*prev
,
41 struct list_head
*next
)
50 * list_add - add a new entry
51 * @new: new entry to be added
52 * @head: list head to add it after
54 * Insert a new entry after the specified head.
55 * This is good for implementing stacks.
57 static inline void list_add(struct list_head
*new, struct list_head
*head
)
59 __list_add(new, head
, head
->next
);
63 * list_add_tail - add a new entry
64 * @new: new entry to be added
65 * @head: list head to add it before
67 * Insert a new entry before the specified head.
68 * This is useful for implementing queues.
70 static inline void list_add_tail(struct list_head
*new, struct list_head
*head
)
72 __list_add(new, head
->prev
, head
);
76 * Delete a list entry by making the prev/next entries
77 * point to each other.
79 * This is only for internal list manipulation where we know
80 * the prev/next entries already!
82 static inline void __list_del(struct list_head
*prev
, struct list_head
*next
)
89 * list_del - deletes entry from list.
90 * @entry: the element to delete from the list.
91 * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
93 static inline void list_del(struct list_head
*entry
)
95 __list_del(entry
->prev
, entry
->next
);
96 entry
->next
= (void *) 0;
97 entry
->prev
= (void *) 0;
101 * list_del_init - deletes entry from list and reinitialize it.
102 * @entry: the element to delete from the list.
104 static inline void list_del_init(struct list_head
*entry
)
106 __list_del(entry
->prev
, entry
->next
);
107 INIT_LIST_HEAD(entry
);
111 * list_move - delete from one list and add as another's head
112 * @list: the entry to move
113 * @head: the head that will precede our entry
115 static inline void list_move(struct list_head
*list
, struct list_head
*head
)
117 __list_del(list
->prev
, list
->next
);
118 list_add(list
, head
);
122 * list_move_tail - delete from one list and add as another's tail
123 * @list: the entry to move
124 * @head: the head that will follow our entry
126 static inline void list_move_tail(struct list_head
*list
,
127 struct list_head
*head
)
129 __list_del(list
->prev
, list
->next
);
130 list_add_tail(list
, head
);
134 * list_empty - tests whether a list is empty
135 * @head: the list to test.
137 static inline int list_empty(struct list_head
*head
)
139 return head
->next
== head
;
142 static inline void __list_splice(struct list_head
*list
,
143 struct list_head
*head
)
145 struct list_head
*first
= list
->next
;
146 struct list_head
*last
= list
->prev
;
147 struct list_head
*at
= head
->next
;
157 * list_splice - join two lists
158 * @list: the new list to add.
159 * @head: the place to add it in the first list.
161 static inline void list_splice(struct list_head
*list
, struct list_head
*head
)
163 if (!list_empty(list
))
164 __list_splice(list
, head
);
168 * list_splice_init - join two lists and reinitialise the emptied list.
169 * @list: the new list to add.
170 * @head: the place to add it in the first list.
172 * The list at @list is reinitialised
174 static inline void list_splice_init(struct list_head
*list
,
175 struct list_head
*head
)
177 if (!list_empty(list
)) {
178 __list_splice(list
, head
);
179 INIT_LIST_HEAD(list
);
184 * list_entry - get the struct for this entry
185 * @ptr: the &struct list_head pointer.
186 * @type: the type of the struct this is embedded in.
187 * @member: the name of the list_struct within the struct.
189 #define list_entry(ptr, type, member) \
190 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
193 * list_for_each - iterate over a list
194 * @pos: the &struct list_head to use as a loop counter.
195 * @head: the head for your list.
197 #define list_for_each(pos, head) \
198 for (pos = (head)->next; pos != (head); \
201 * list_for_each_prev - iterate over a list backwards
202 * @pos: the &struct list_head to use as a loop counter.
203 * @head: the head for your list.
205 #define list_for_each_prev(pos, head) \
206 for (pos = (head)->prev; pos != (head); \
210 * list_for_each_safe - iterate over a list safe against removal of list entry
211 * @pos: the &struct list_head to use as a loop counter.
212 * @n: another &struct list_head to use as temporary storage
213 * @head: the head for your list.
215 #define list_for_each_safe(pos, n, head) \
216 for (pos = (head)->next, n = pos->next; pos != (head); \
217 pos = n, n = pos->next)
220 * list_for_each_entry - iterate over list of given type
221 * @pos: the type * to use as a loop counter.
222 * @head: the head for your list.
223 * @member: the name of the list_struct within the struct.
225 #define list_for_each_entry(pos, head, member) \
226 for (pos = list_entry((head)->next, typeof(*pos), member); \
227 &pos->member != (head); \
228 pos = list_entry(pos->member.next, typeof(*pos), member))
231 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
232 * @pos: the type * to use as a loop counter.
233 * @n: another type * to use as temporary storage
234 * @head: the head for your list.
235 * @member: the name of the list_struct within the struct.
237 #define list_for_each_entry_safe(pos, n, head, member) \
238 for (pos = list_entry((head)->next, typeof(*pos), member), \
239 n = list_entry(pos->member.next, typeof(*pos), member); \
240 &pos->member != (head); \
241 pos = n, n = list_entry(n->member.next, typeof(*n), member))