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 
24 struct list_head {
25 	struct list_head *next, *prev;
26 };
27 
28 
29 #define LIST_HEAD_INIT(name) { &(name), &(name) }
30 
31 #define LIST_HEAD(name) \
32 	struct list_head name = LIST_HEAD_INIT(name)
33 
34 /**
35  * list_entry - get the struct for this entry
36  * @ptr:	the &struct list_head pointer.
37  * @type:	the type of the struct this is embedded in.
38  * @member:	the name of the list_head within the struct.
39  */
40 #define list_entry(ptr, type, member) \
41 	container_of(ptr, type, member)
42 
43 /**
44  * list_for_each_entry	-	iterate over list of given type
45  * @pos:	the type * to use as a loop cursor.
46  * @head:	the head for your list.
47  * @member:	the name of the list_head within the struct.
48  */
49 #define list_for_each_entry(pos, head, member)				\
50 	for (pos = list_entry((head)->next, typeof(*pos), member);	\
51 	     &pos->member != (head); 	\
52 	     pos = list_entry(pos->member.next, typeof(*pos), member))
53 
54 /**
55  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
56  * @pos:	the type * to use as a loop cursor.
57  * @n:		another type * to use as temporary storage
58  * @head:	the head for your list.
59  * @member:	the name of the list_head within the struct.
60  */
61 #define list_for_each_entry_safe(pos, n, head, member)			\
62 	for (pos = list_entry((head)->next, typeof(*pos), member),	\
63 		n = list_entry(pos->member.next, typeof(*pos), member);	\
64 	     &pos->member != (head);					\
65 	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
66 
67 /**
68  * list_empty - tests whether a list is empty
69  * @head: the list to test.
70  */
list_empty(const struct list_head * head)71 static inline int list_empty(const struct list_head *head)
72 {
73 	return head->next == head;
74 }
75 
76 /*
77  * Insert a new entry between two known consecutive entries.
78  *
79  * This is only for internal list manipulation where we know
80  * the prev/next entries already!
81  */
__list_add(struct list_head * _new,struct list_head * prev,struct list_head * next)82 static inline void __list_add(struct list_head *_new,
83 			      struct list_head *prev,
84 			      struct list_head *next)
85 {
86 	next->prev = _new;
87 	_new->next = next;
88 	_new->prev = prev;
89 	prev->next = _new;
90 }
91 
92 /**
93  * list_add_tail - add a new entry
94  * @new: new entry to be added
95  * @head: list head to add it before
96  *
97  * Insert a new entry before the specified head.
98  * This is useful for implementing queues.
99  */
list_add_tail(struct list_head * _new,struct list_head * head)100 static inline void list_add_tail(struct list_head *_new, struct list_head *head)
101 {
102 	__list_add(_new, head->prev, head);
103 }
104 
105 /*
106  * Delete a list entry by making the prev/next entries
107  * point to each other.
108  *
109  * This is only for internal list manipulation where we know
110  * the prev/next entries already!
111  */
__list_del(struct list_head * prev,struct list_head * next)112 static inline void __list_del(struct list_head *prev, struct list_head *next)
113 {
114 	next->prev = prev;
115 	prev->next = next;
116 }
117 
118 #define LIST_POISON1  ((void *) 0x00100100)
119 #define LIST_POISON2  ((void *) 0x00200200)
120 /**
121  * list_del - deletes entry from list.
122  * @entry: the element to delete from the list.
123  * Note: list_empty() on entry does not return true after this, the entry is
124  * in an undefined state.
125  */
list_del(struct list_head * entry)126 static inline void list_del(struct list_head *entry)
127 {
128 	__list_del(entry->prev, entry->next);
129 	entry->next = (struct list_head*)LIST_POISON1;
130 	entry->prev = (struct list_head*)LIST_POISON2;
131 }
132 #endif
133