1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LIST_H
3 #define LIST_H
4
5 /*
6 * Copied from include/linux/...
7 */
8
9 #undef offsetof
10 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
11
12 /**
13 * container_of - cast a member of a structure out to the containing structure
14 * @ptr: the pointer to the member.
15 * @type: the type of the container struct this is embedded in.
16 * @member: the name of the member within the struct.
17 *
18 */
19 #define container_of(ptr, type, member) ({ \
20 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
21 (type *)( (char *)__mptr - offsetof(type,member) );})
22
23 struct list_head {
24 struct list_head *next, *prev;
25 };
26
27 #define LIST_HEAD_INIT(name) { &(name), &(name) }
28
29 #define LIST_HEAD(name) \
30 struct list_head name = LIST_HEAD_INIT(name)
31
32 /**
33 * list_entry - get the struct for this entry
34 * @ptr: the &struct list_head pointer.
35 * @type: the type of the struct this is embedded in.
36 * @member: the name of the list_head within the struct.
37 */
38 #define list_entry(ptr, type, member) \
39 container_of(ptr, type, member)
40
41 /**
42 * list_for_each_entry - iterate over list of given type
43 * @pos: the type * to use as a loop cursor.
44 * @head: the head for your list.
45 * @member: the name of the list_head within the struct.
46 */
47 #define list_for_each_entry(pos, head, member) \
48 for (pos = list_entry((head)->next, typeof(*pos), member); \
49 &pos->member != (head); \
50 pos = list_entry(pos->member.next, typeof(*pos), member))
51
52 /**
53 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
54 * @pos: the type * to use as a loop cursor.
55 * @n: another type * to use as temporary storage
56 * @head: the head for your list.
57 * @member: the name of the list_head within the struct.
58 */
59 #define list_for_each_entry_safe(pos, n, head, member) \
60 for (pos = list_entry((head)->next, typeof(*pos), member), \
61 n = list_entry(pos->member.next, typeof(*pos), member); \
62 &pos->member != (head); \
63 pos = n, n = list_entry(n->member.next, typeof(*n), member))
64
65 /**
66 * list_empty - tests whether a list is empty
67 * @head: the list to test.
68 */
list_empty(const struct list_head * head)69 static inline int list_empty(const struct list_head *head)
70 {
71 return head->next == head;
72 }
73
74 /*
75 * Insert a new entry between two known consecutive entries.
76 *
77 * This is only for internal list manipulation where we know
78 * the prev/next entries already!
79 */
__list_add(struct list_head * _new,struct list_head * prev,struct list_head * next)80 static inline void __list_add(struct list_head *_new,
81 struct list_head *prev,
82 struct list_head *next)
83 {
84 next->prev = _new;
85 _new->next = next;
86 _new->prev = prev;
87 prev->next = _new;
88 }
89
90 /**
91 * list_add_tail - add a new entry
92 * @new: new entry to be added
93 * @head: list head to add it before
94 *
95 * Insert a new entry before the specified head.
96 * This is useful for implementing queues.
97 */
list_add_tail(struct list_head * _new,struct list_head * head)98 static inline void list_add_tail(struct list_head *_new, struct list_head *head)
99 {
100 __list_add(_new, head->prev, head);
101 }
102
103 /*
104 * Delete a list entry by making the prev/next entries
105 * point to each other.
106 *
107 * This is only for internal list manipulation where we know
108 * the prev/next entries already!
109 */
__list_del(struct list_head * prev,struct list_head * next)110 static inline void __list_del(struct list_head *prev, struct list_head *next)
111 {
112 next->prev = prev;
113 prev->next = next;
114 }
115
116 #define LIST_POISON1 ((void *) 0x00100100)
117 #define LIST_POISON2 ((void *) 0x00200200)
118 /**
119 * list_del - deletes entry from list.
120 * @entry: the element to delete from the list.
121 * Note: list_empty() on entry does not return true after this, the entry is
122 * in an undefined state.
123 */
list_del(struct list_head * entry)124 static inline void list_del(struct list_head *entry)
125 {
126 __list_del(entry->prev, entry->next);
127 entry->next = (struct list_head*)LIST_POISON1;
128 entry->prev = (struct list_head*)LIST_POISON2;
129 }
130 #endif
131