1 /**
2 *
3 * Linux kernel linked lists,
4 * modified for userspace by
5 * - kazutomo@mcs.anl.gov
6 *
7 * This is obviously GPL licensed.
8 */
9
10 #include "struct.h"
11 #define _LISTS_C
12
13 #include "proto.h"
14 #include "lists.h"
15
16 /*
17 * Insert a new entry between two known consecutive entries.
18 *
19 * This is only for internal list manipulation where we know
20 * the prev/next entries already!
21 */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)22 static inline void __list_add(struct list_head *new, struct list_head *prev, struct list_head *next)
23 {
24 next->prev = new;
25 new->next = next;
26 new->prev = prev;
27 prev->next = new;
28 }
29
30 /**
31 * list_add - add a new entry
32 * @param new new entry to be added
33 * @param head list head to add it after
34 *
35 * Insert a new entry after the specified head.
36 * This is good for implementing stacks.
37 */
list_add(struct list_head * new,struct list_head * head)38 void list_add(struct list_head *new, struct list_head *head)
39 {
40 __list_add(new, head, head->next);
41 }
42
43 /**
44 * list_add_tail - add a new entry
45 * @param new new entry to be added
46 * @param head list head to add it before
47 *
48 * Insert a new entry before the specified head.
49 * This is useful for implementing queues.
50 */
list_add_tail(struct list_head * new,struct list_head * head)51 void list_add_tail(struct list_head *new, struct list_head *head)
52 {
53 __list_add(new, head->prev, head);
54 }
55
56 /*
57 * Delete a list entry by making the prev/next entries
58 * point to each other.
59 *
60 * This is only for internal list manipulation where we know
61 * the prev/next entries already!
62 */
__list_del(struct list_head * prev,struct list_head * next)63 static inline void __list_del(struct list_head *prev, struct list_head *next)
64 {
65 next->prev = prev;
66 prev->next = next;
67 }
68
69 /**
70 * list_del - deletes entry from list.
71 * @param entry the element to delete from the list.
72 * Note: list_empty on entry does not return true after this, the entry is
73 * in an undefined state.
74 */
list_del(struct list_head * entry)75 void list_del(struct list_head *entry)
76 {
77 __list_del(entry->prev, entry->next);
78 entry->next = LIST_POISON1;
79 entry->prev = LIST_POISON2;
80 }
81
82 /**
83 * list_del_init - deletes entry from list and reinitialize it.
84 * @param entry the element to delete from the list.
85 */
list_del_init(struct list_head * entry)86 void list_del_init(struct list_head *entry)
87 {
88 __list_del(entry->prev, entry->next);
89 INIT_LIST_HEAD(entry);
90 }
91
92 /**
93 * list_move - delete from one list and add as another's head
94 * @param list the entry to move
95 * @param head the head that will precede our entry
96 */
list_move(struct list_head * list,struct list_head * head)97 void list_move(struct list_head *list, struct list_head *head)
98 {
99 __list_del(list->prev, list->next);
100 list_add(list, head);
101 }
102
103 /**
104 * list_move_tail - delete from one list and add as another's tail
105 * @param list the entry to move
106 * @param head the head that will follow our entry
107 */
list_move_tail(struct list_head * list,struct list_head * head)108 void list_move_tail(struct list_head *list, struct list_head *head)
109 {
110 __list_del(list->prev, list->next);
111 list_add_tail(list, head);
112 }
113
114 /**
115 * list_empty - tests whether a list is empty
116 * @param head the list to test.
117 */
list_empty(const struct list_head * head)118 int list_empty(const struct list_head *head)
119 {
120 return head->next == head;
121 }
122
__list_splice(struct list_head * list,struct list_head * head)123 static inline void __list_splice(struct list_head *list, struct list_head *head)
124 {
125 struct list_head *first = list->next;
126 struct list_head *last = list->prev;
127 struct list_head *at = head->next;
128
129 first->prev = head;
130 head->next = first;
131
132 last->next = at;
133 at->prev = last;
134 }
135
136 /**
137 * list_splice - join two lists
138 * @param list the new list to add.
139 * @param head the place to add it in the first list.
140 */
list_splice(struct list_head * list,struct list_head * head)141 void list_splice(struct list_head *list, struct list_head *head)
142 {
143 if (!list_empty(list))
144 __list_splice(list, head);
145 }
146
147 /**
148 * list_splice_init - join two lists and reinitialize the emptied list.
149 * @param list the new list to add (the list is reinitialised).
150 * @param head the place to add it in the first list.
151 */
list_splice_init(struct list_head * list,struct list_head * head)152 void list_splice_init(struct list_head *list, struct list_head *head)
153 {
154 if (!list_empty(list)) {
155 __list_splice(list, head);
156 INIT_LIST_HEAD(list);
157 }
158 }
159
160 #undef _LISTS_C
161