1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LIST_H |
3 | #define _LIST_H |
4 | |
5 | /* Stripped down implementation of linked list taken |
6 | * from the Linux Kernel. |
7 | */ |
8 | |
9 | /* |
10 | * Simple doubly linked list implementation. |
11 | * |
12 | * Some of the internal functions ("__xxx") are useful when |
13 | * manipulating whole lists rather than single entries, as |
14 | * sometimes we already know the next/prev entries and we can |
15 | * generate better code by using them directly rather than |
16 | * using the generic single-entry routines. |
17 | */ |
18 | |
19 | struct list_head { |
20 | struct list_head *next, *prev; |
21 | }; |
22 | |
23 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
24 | |
25 | #define LIST_HEAD(name) \ |
26 | struct list_head name = LIST_HEAD_INIT(name) |
27 | |
28 | static inline void INIT_LIST_HEAD(struct list_head *list) |
29 | { |
30 | list->next = list; |
31 | list->prev = list; |
32 | } |
33 | |
34 | /* |
35 | * Insert a new entry between two known consecutive entries. |
36 | * |
37 | * This is only for internal list manipulation where we know |
38 | * the prev/next entries already! |
39 | */ |
40 | static inline void __list_add(struct list_head *new, |
41 | struct list_head *prev, |
42 | struct list_head *next) |
43 | { |
44 | next->prev = new; |
45 | new->next = next; |
46 | new->prev = prev; |
47 | prev->next = new; |
48 | } |
49 | |
50 | /** |
51 | * list_add - add a new entry |
52 | * @new: new entry to be added |
53 | * @head: list head to add it after |
54 | * |
55 | * Insert a new entry after the specified head. |
56 | * This is good for implementing stacks. |
57 | */ |
58 | static inline void list_add(struct list_head *new, struct list_head *head) |
59 | { |
60 | __list_add(new, prev: head, next: head->next); |
61 | } |
62 | |
63 | /* |
64 | * Delete a list entry by making the prev/next entries |
65 | * point to each other. |
66 | * |
67 | * This is only for internal list manipulation where we know |
68 | * the prev/next entries already! |
69 | */ |
70 | static inline void __list_del(struct list_head * prev, struct list_head * next) |
71 | { |
72 | next->prev = prev; |
73 | prev->next = next; |
74 | } |
75 | |
76 | #define POISON_POINTER_DELTA 0 |
77 | #define LIST_POISON1 ((void *) 0x00100100 + POISON_POINTER_DELTA) |
78 | #define LIST_POISON2 ((void *) 0x00200200 + POISON_POINTER_DELTA) |
79 | |
80 | static inline void __list_del_entry(struct list_head *entry) |
81 | { |
82 | __list_del(prev: entry->prev, next: entry->next); |
83 | } |
84 | |
85 | /** |
86 | * list_del - deletes entry from list. |
87 | * @entry: the element to delete from the list. |
88 | * Note: list_empty() on entry does not return true after this, the entry is |
89 | * in an undefined state. |
90 | */ |
91 | static inline void list_del(struct list_head *entry) |
92 | { |
93 | __list_del(prev: entry->prev, next: entry->next); |
94 | entry->next = LIST_POISON1; |
95 | entry->prev = LIST_POISON2; |
96 | } |
97 | |
98 | /** |
99 | * list_entry - get the struct for this entry |
100 | * @ptr: the &struct list_head pointer. |
101 | * @type: the type of the struct this is embedded in. |
102 | * @member: the name of the list_head within the struct. |
103 | */ |
104 | #define list_entry(ptr, type, member) \ |
105 | container_of(ptr, type, member) |
106 | /** |
107 | * list_for_each - iterate over a list |
108 | * @pos: the &struct list_head to use as a loop cursor. |
109 | * @head: the head for your list. |
110 | */ |
111 | #define list_for_each(pos, head) \ |
112 | for (pos = (head)->next; pos != (head); pos = pos->next) |
113 | |
114 | /** |
115 | * list_for_each_safe - iterate over a list safe against removal of list entry |
116 | * @pos: the &struct list_head to use as a loop cursor. |
117 | * @n: another &struct list_head to use as temporary storage |
118 | * @head: the head for your list. |
119 | */ |
120 | #define list_for_each_safe(pos, n, head) \ |
121 | for (pos = (head)->next, n = pos->next; pos != (head); \ |
122 | pos = n, n = pos->next) |
123 | |
124 | #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) |
125 | |
126 | /** |
127 | * container_of - cast a member of a structure out to the containing structure |
128 | * @ptr: the pointer to the member. |
129 | * @type: the type of the container struct this is embedded in. |
130 | * @member: the name of the member within the struct. |
131 | * |
132 | */ |
133 | #define container_of(ptr, type, member) ({ \ |
134 | const typeof( ((type *)0)->member ) *__mptr = (ptr); \ |
135 | (type *)( (char *)__mptr - offsetof(type,member) );}) |
136 | |
137 | #endif |
138 | |