1 #ifndef _LIST_H
2 #define _LIST_H
3
4 /* Stripped down implementation of linked list taken
5 * from the Linux Kernel.
6 */
7
8 /*
9 * Simple doubly linked list implementation.
10 *
11 * Some of the internal functions ("__xxx") are useful when
12 * manipulating whole lists rather than single entries, as
13 * sometimes we already know the next/prev entries and we can
14 * generate better code by using them directly rather than
15 * using the generic single-entry routines.
16 */
17
18 struct list_head {
19 struct list_head *next, *prev;
20 };
21
22 #define LIST_HEAD_INIT(name) { &(name), &(name) }
23
24 #define LIST_HEAD(name) \
25 struct list_head name = LIST_HEAD_INIT(name)
26
INIT_LIST_HEAD(struct list_head * list)27 static inline void INIT_LIST_HEAD(struct list_head *list)
28 {
29 list->next = list;
30 list->prev = list;
31 }
32
33 /*
34 * Insert a new entry between two known consecutive entries.
35 *
36 * This is only for internal list manipulation where we know
37 * the prev/next entries already!
38 */
__list_add(struct list_head * new,struct list_head * prev,struct list_head * next)39 static inline void __list_add(struct list_head *new,
40 struct list_head *prev,
41 struct list_head *next)
42 {
43 next->prev = new;
44 new->next = next;
45 new->prev = prev;
46 prev->next = new;
47 }
48
49 /**
50 * list_add - add a new entry
51 * @new: new entry to be added
52 * @head: list head to add it after
53 *
54 * Insert a new entry after the specified head.
55 * This is good for implementing stacks.
56 */
list_add(struct list_head * new,struct list_head * head)57 static inline void list_add(struct list_head *new, struct list_head *head)
58 {
59 __list_add(new, head, head->next);
60 }
61
62 /*
63 * Delete a list entry by making the prev/next entries
64 * point to each other.
65 *
66 * This is only for internal list manipulation where we know
67 * the prev/next entries already!
68 */
__list_del(struct list_head * prev,struct list_head * next)69 static inline void __list_del(struct list_head * prev, struct list_head * next)
70 {
71 next->prev = prev;
72 prev->next = next;
73 }
74
75 #define POISON_POINTER_DELTA 0
76 #define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA)
77 #define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA)
78
79 /**
80 * list_del - deletes entry from list.
81 * @entry: the element to delete from the list.
82 * Note: list_empty() on entry does not return true after this, the entry is
83 * in an undefined state.
84 */
__list_del_entry(struct list_head * entry)85 static inline void __list_del_entry(struct list_head *entry)
86 {
87 __list_del(entry->prev, entry->next);
88 }
89
list_del(struct list_head * entry)90 static inline void list_del(struct list_head *entry)
91 {
92 __list_del(entry->prev, entry->next);
93 entry->next = LIST_POISON1;
94 entry->prev = LIST_POISON2;
95 }
96
97 /**
98 * list_entry - get the struct for this entry
99 * @ptr: the &struct list_head pointer.
100 * @type: the type of the struct this is embedded in.
101 * @member: the name of the list_head within the struct.
102 */
103 #define list_entry(ptr, type, member) \
104 container_of(ptr, type, member)
105 /**
106 * list_for_each - iterate over a list
107 * @pos: the &struct list_head to use as a loop cursor.
108 * @head: the head for your list.
109 */
110 #define list_for_each(pos, head) \
111 for (pos = (head)->next; pos != (head); pos = pos->next)
112
113 /**
114 * list_for_each_safe - iterate over a list safe against removal of list entry
115 * @pos: the &struct list_head to use as a loop cursor.
116 * @n: another &struct list_head to use as temporary storage
117 * @head: the head for your list.
118 */
119 #define list_for_each_safe(pos, n, head) \
120 for (pos = (head)->next, n = pos->next; pos != (head); \
121 pos = n, n = pos->next)
122
123 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
124
125 /**
126 * container_of - cast a member of a structure out to the containing structure
127 * @ptr: the pointer to the member.
128 * @type: the type of the container struct this is embedded in.
129 * @member: the name of the member within the struct.
130 *
131 */
132 #define container_of(ptr, type, member) ({ \
133 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
134 (type *)( (char *)__mptr - offsetof(type,member) );})
135
136 #endif
137