1 | #if !defined(_BLKID_LIST_H) && !defined(LIST_HEAD) |
---|
2 | #define _BLKID_LIST_H |
---|
3 | |
---|
4 | #ifdef __cplusplus |
---|
5 | extern "C" { |
---|
6 | #endif |
---|
7 | |
---|
8 | #ifdef __GNUC__ |
---|
9 | #define _INLINE_ static __inline__ |
---|
10 | #else /* For Watcom C */ |
---|
11 | #define _INLINE_ static inline |
---|
12 | #endif |
---|
13 | |
---|
14 | /* |
---|
15 | * Simple doubly linked list implementation. |
---|
16 | * |
---|
17 | * Some of the internal functions ("__xxx") are useful when |
---|
18 | * manipulating whole lists rather than single entries, as |
---|
19 | * sometimes we already know the next/prev entries and we can |
---|
20 | * generate better code by using them directly rather than |
---|
21 | * using the generic single-entry routines. |
---|
22 | */ |
---|
23 | |
---|
24 | struct list_head { |
---|
25 | struct list_head *next, *prev; |
---|
26 | }; |
---|
27 | |
---|
28 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
---|
29 | |
---|
30 | #define LIST_HEAD(name) \ |
---|
31 | struct list_head name = LIST_HEAD_INIT(name) |
---|
32 | |
---|
33 | #define INIT_LIST_HEAD(ptr) do { \ |
---|
34 | (ptr)->next = (ptr); (ptr)->prev = (ptr); \ |
---|
35 | } while (0) |
---|
36 | |
---|
37 | /* |
---|
38 | * Insert a new entry between two known consecutive entries. |
---|
39 | * |
---|
40 | * This is only for internal list manipulation where we know |
---|
41 | * the prev/next entries already! |
---|
42 | */ |
---|
43 | _INLINE_ void __list_add(struct list_head * add, |
---|
44 | struct list_head * prev, |
---|
45 | struct list_head * next) |
---|
46 | { |
---|
47 | next->prev = add; |
---|
48 | add->next = next; |
---|
49 | add->prev = prev; |
---|
50 | prev->next = add; |
---|
51 | } |
---|
52 | |
---|
53 | /** |
---|
54 | * list_add - add a new entry |
---|
55 | * @add: new entry to be added |
---|
56 | * @head: list head to add it after |
---|
57 | * |
---|
58 | * Insert a new entry after the specified head. |
---|
59 | * This is good for implementing stacks. |
---|
60 | */ |
---|
61 | _INLINE_ void list_add(struct list_head *add, struct list_head *head) |
---|
62 | { |
---|
63 | __list_add(add, head, head->next); |
---|
64 | } |
---|
65 | |
---|
66 | /** |
---|
67 | * list_add_tail - add a new entry |
---|
68 | * @add: new entry to be added |
---|
69 | * @head: list head to add it before |
---|
70 | * |
---|
71 | * Insert a new entry before the specified head. |
---|
72 | * This is useful for implementing queues. |
---|
73 | */ |
---|
74 | _INLINE_ void list_add_tail(struct list_head *add, struct list_head *head) |
---|
75 | { |
---|
76 | __list_add(add, head->prev, head); |
---|
77 | } |
---|
78 | |
---|
79 | /* |
---|
80 | * Delete a list entry by making the prev/next entries |
---|
81 | * point to each other. |
---|
82 | * |
---|
83 | * This is only for internal list manipulation where we know |
---|
84 | * the prev/next entries already! |
---|
85 | */ |
---|
86 | _INLINE_ void __list_del(struct list_head * prev, |
---|
87 | struct list_head * next) |
---|
88 | { |
---|
89 | next->prev = prev; |
---|
90 | prev->next = next; |
---|
91 | } |
---|
92 | |
---|
93 | /** |
---|
94 | * list_del - deletes entry from list. |
---|
95 | * @entry: the element to delete from the list. |
---|
96 | * |
---|
97 | * list_empty() on @entry does not return true after this, @entry is |
---|
98 | * in an undefined state. |
---|
99 | */ |
---|
100 | _INLINE_ void list_del(struct list_head *entry) |
---|
101 | { |
---|
102 | __list_del(entry->prev, entry->next); |
---|
103 | } |
---|
104 | |
---|
105 | /** |
---|
106 | * list_del_init - deletes entry from list and reinitialize it. |
---|
107 | * @entry: the element to delete from the list. |
---|
108 | */ |
---|
109 | _INLINE_ void list_del_init(struct list_head *entry) |
---|
110 | { |
---|
111 | __list_del(entry->prev, entry->next); |
---|
112 | INIT_LIST_HEAD(entry); |
---|
113 | } |
---|
114 | |
---|
115 | /** |
---|
116 | * list_empty - tests whether a list is empty |
---|
117 | * @head: the list to test. |
---|
118 | */ |
---|
119 | _INLINE_ int list_empty(struct list_head *head) |
---|
120 | { |
---|
121 | return head->next == head; |
---|
122 | } |
---|
123 | |
---|
124 | /** |
---|
125 | * list_splice - join two lists |
---|
126 | * @list: the new list to add. |
---|
127 | * @head: the place to add it in the first list. |
---|
128 | */ |
---|
129 | _INLINE_ void list_splice(struct list_head *list, struct list_head *head) |
---|
130 | { |
---|
131 | struct list_head *first = list->next; |
---|
132 | |
---|
133 | if (first != list) { |
---|
134 | struct list_head *last = list->prev; |
---|
135 | struct list_head *at = head->next; |
---|
136 | |
---|
137 | first->prev = head; |
---|
138 | head->next = first; |
---|
139 | |
---|
140 | last->next = at; |
---|
141 | at->prev = last; |
---|
142 | } |
---|
143 | } |
---|
144 | |
---|
145 | /** |
---|
146 | * list_entry - get the struct for this entry |
---|
147 | * @ptr: the &struct list_head pointer. |
---|
148 | * @type: the type of the struct this is embedded in. |
---|
149 | * @member: the name of the list_struct within the struct. |
---|
150 | */ |
---|
151 | #define list_entry(ptr, type, member) \ |
---|
152 | ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) |
---|
153 | |
---|
154 | /** |
---|
155 | * list_for_each - iterate over elements in a list |
---|
156 | * @pos: the &struct list_head to use as a loop counter. |
---|
157 | * @head: the head for your list. |
---|
158 | */ |
---|
159 | #define list_for_each(pos, head) \ |
---|
160 | for (pos = (head)->next; pos != (head); pos = pos->next) |
---|
161 | |
---|
162 | /** |
---|
163 | * list_for_each_safe - iterate over elements in a list, but don't dereference |
---|
164 | * pos after the body is done (in case it is freed) |
---|
165 | * @pos: the &struct list_head to use as a loop counter. |
---|
166 | * @pnext: the &struct list_head to use as a pointer to the next item. |
---|
167 | * @head: the head for your list (not included in iteration). |
---|
168 | */ |
---|
169 | #define list_for_each_safe(pos, pnext, head) \ |
---|
170 | for (pos = (head)->next, pnext = pos->next; pos != (head); \ |
---|
171 | pos = pnext, pnext = pos->next) |
---|
172 | |
---|
173 | #undef _INLINE_ |
---|
174 | |
---|
175 | #ifdef __cplusplus |
---|
176 | } |
---|
177 | #endif |
---|
178 | |
---|
179 | #endif /* _BLKID_LIST_H */ |
---|