1#ifndef _LINUX_LIST_H
2#define _LINUX_LIST_H
3
4#include <stdio.h>
5
6#ifndef offsetof
7/**
8 * Get offset of a member
9 */
10#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
11#endif
12
13#ifndef container_of
14/**
15 * Casts a member of a structure out to the containing structure
16 * @param ptr        the pointer to the member.
17 * @param type       the type of the container struct this is embedded in.
18 * @param member     the name of the member within the struct.
19 *
20 */
21#define container_of(ptr, type, member) ({                      \
22        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
23	        (type *)( (char *)__mptr - offsetof(type,member) );})
24#endif
25
26/*
27 * These are non-NULL pointers that will result in page faults
28 * under normal circumstances, used to verify that nobody uses
29 * non-initialized list entries.
30 */
31#define LIST_POISON1  ((void *) 0x00100100)
32#define LIST_POISON2  ((void *) 0x00200200)
33
34struct list_head {
35	struct list_head *next, *prev;
36};
37
38#define LIST_HEAD_INIT(name) { &(name), &(name) }
39
40#define LIST_HEAD(name) \
41	struct list_head name = LIST_HEAD_INIT(name)
42
43static inline void INIT_LIST_HEAD(struct list_head *list)
44{
45	list->next = list;
46	list->prev = list;
47}
48
49/*
50 * Insert a new entry between two known consecutive entries.
51 *
52 * This is only for internal list manipulation where we know
53 * the prev/next entries already!
54 */
55static inline void __list_add(struct list_head *new,
56			      struct list_head *prev,
57			      struct list_head *next)
58{
59	next->prev = new;
60	new->next = next;
61	new->prev = prev;
62	prev->next = new;
63}
64
65/**
66 * list_add - add a new entry
67 * @new: new entry to be added
68 * @head: list head to add it after
69 *
70 * Insert a new entry after the specified head.
71 * This is good for implementing stacks.
72 */
73static inline void list_add(struct list_head *new, struct list_head *head)
74{
75	__list_add(new, head, head->next);
76}
77
78/**
79 * list_add_tail - add a new entry
80 * @new: new entry to be added
81 * @head: list head to add it before
82 *
83 * Insert a new entry before the specified head.
84 * This is useful for implementing queues.
85 */
86static inline void list_add_tail(struct list_head *new, struct list_head *head)
87{
88	__list_add(new, head->prev, head);
89}
90
91/*
92 * Delete a list entry by making the prev/next entries
93 * point to each other.
94 *
95 * This is only for internal list manipulation where we know
96 * the prev/next entries already!
97 */
98static inline void __list_del(struct list_head * prev, struct list_head * next)
99{
100	next->prev = prev;
101	prev->next = next;
102}
103
104/**
105 * list_del - deletes entry from list.
106 * @entry: the element to delete from the list.
107 * Note: list_empty on entry does not return true after this, the entry is
108 * in an undefined state.
109 */
110static inline void list_del(struct list_head *entry)
111{
112	__list_del(entry->prev, entry->next);
113	entry->next = LIST_POISON1;
114	entry->prev = LIST_POISON2;
115}
116
117/**
118 * __list_for_each	-	iterate over a list
119 * @pos:	the &struct list_head to use as a loop counter.
120 * @head:	the head for your list.
121 *
122 * This variant differs from list_for_each() in that it's the
123 * simplest possible list iteration code, no prefetching is done.
124 * Use this for code that knows the list to be very short (empty
125 * or 1 entry) most of the time.
126 */
127#define __list_for_each(pos, head) \
128	for (pos = (head)->next; pos != (head); pos = pos->next)
129
130/**
131 * list_for_each_safe	-	iterate over a list safe against removal of list entry
132 * @pos:	the &struct list_head to use as a loop counter.
133 * @n:		another &struct list_head to use as temporary storage
134 * @head:	the head for your list.
135 */
136#define list_for_each_safe(pos, n, head) \
137	for (pos = (head)->next, n = pos->next; pos != (head); \
138		pos = n, n = pos->next)
139
140/**
141 * list_entry - get the struct for this entry
142 * @ptr:        the &struct list_head pointer.
143 * @type:       the type of the struct this is embedded in.
144 * @member:     the name of the list_struct within the struct.
145 */
146#define list_entry(ptr, type, member) \
147        container_of(ptr, type, member)
148
149static inline int list_len(struct list_head *head_p)
150{
151	struct list_head *p;
152	int n = 0;
153
154	__list_for_each(p, head_p) {
155		n++;
156	}
157
158	return n;
159}
160
161/**
162 * list_empty - tests whether a list is empty
163 * @head: the list to test.
164 */
165static inline int list_empty(const struct list_head *head)
166{
167	return head->next == head;
168}
169
170/**
171 * list_first - Returns first entry on list, or NULL if empty
172 * @head: the list
173 */
174static inline struct list_head *list_first(const struct list_head *head)
175{
176	return list_empty(head) ? NULL : head->next;
177}
178
179/**
180 * list_move_tail - delete from one list and add as another's tail
181 * @list: the entry to move
182 * @head: the head that will follow our entry
183 */
184static inline void list_move_tail(struct list_head *list,
185				  struct list_head *head)
186{
187        __list_del(list->prev, list->next);
188        list_add_tail(list, head);
189}
190
191static inline void __list_splice(struct list_head *list,
192                                 struct list_head *head)
193{
194        struct list_head *first = list->next;
195        struct list_head *last = list->prev;
196        struct list_head *at = head->next;
197
198        first->prev = head;
199        head->next = first;
200
201        last->next = at;
202        at->prev = last;
203}
204
205/**
206 *  * list_splice - join two lists
207 *   * @list: the new list to add.
208 *    * @head: the place to add it in the first list.
209 *     */
210static inline void list_splice(struct list_head *list, struct list_head *head)
211{
212        if (!list_empty(list))
213                __list_splice(list, head);
214}
215
216/**
217 * list_replace - replace old entry by new one
218 * @old : the element to be replaced
219 * @new : the new element to insert
220 *
221 * If @old was empty, it will be overwritten.
222 */
223static inline void list_replace(struct list_head *old,
224				struct list_head *new)
225{
226	new->next = old->next;
227	new->next->prev = new;
228	new->prev = old->prev;
229	new->prev->next = new;
230}
231
232static inline void list_replace_init(struct list_head *old,
233					struct list_head *new)
234{
235	list_replace(old, new);
236	INIT_LIST_HEAD(old);
237}
238
239#endif
240