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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
52d04485 VM |
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, head, 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 | /** | |
81 | * list_del - deletes entry from list. | |
82 | * @entry: the element to delete from the list. | |
83 | * Note: list_empty() on entry does not return true after this, the entry is | |
84 | * in an undefined state. | |
85 | */ | |
86 | static inline void __list_del_entry(struct list_head *entry) | |
87 | { | |
88 | __list_del(entry->prev, entry->next); | |
89 | } | |
90 | ||
91 | static inline void list_del(struct list_head *entry) | |
92 | { | |
93 | __list_del(entry->prev, 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. | |
3943f42c | 102 | * @member: the name of the list_head within the struct. |
52d04485 VM |
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 |