1 /**
2 * @file op_list.h
3 * Kernel-style lists
4 *
5 * @remark Copyright 2002 OProfile authors
6 * @remark Read the file COPYING
7 *
8 * @author Linux kernel authors
9 */
10
11 #ifndef OP_LIST_H
12 #define OP_LIST_H
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 /**
29 * list_init - init a new entry
30 * @param ptr the list to init
31 *
32 * Init a list head to create an empty list from it
33 */
list_init(struct list_head * ptr)34 static __inline__ void list_init(struct list_head * ptr)
35 {
36 ptr->next = ptr;
37 ptr->prev = ptr;
38 }
39
40 /*
41 * Insert a new entry between two known consecutive entries.
42 *
43 * This is only for internal list manipulation where we know
44 * the prev/next entries already!
45 */
__list_add(struct list_head * new_entry,struct list_head * prev,struct list_head * next)46 static __inline__ void __list_add(struct list_head * new_entry,
47 struct list_head * prev,
48 struct list_head * next)
49 {
50 next->prev = new_entry;
51 new_entry->next = next;
52 new_entry->prev = prev;
53 prev->next = new_entry;
54 }
55
56 /**
57 * list_add - add a new entry
58 * @param new new entry to be added
59 * @param head list head to add it after
60 *
61 * Insert a new entry after the specified head.
62 * This is good for implementing stacks.
63 */
list_add(struct list_head * new_entry,struct list_head * head)64 static __inline__ void list_add(struct list_head * new_entry, struct list_head * head)
65 {
66 __list_add(new_entry, head, head->next);
67 }
68
69 /**
70 * list_add_tail - add a new entry
71 * @param new new entry to be added
72 * @param head list head to add it before
73 *
74 * Insert a new entry before the specified head.
75 * This is useful for implementing queues.
76 */
list_add_tail(struct list_head * new_entry,struct list_head * head)77 static __inline__ void list_add_tail(struct list_head * new_entry, struct list_head * head)
78 {
79 __list_add(new_entry, head->prev, head);
80 }
81
82 /*
83 * Delete a list entry by making the prev/next entries
84 * point to each other.
85 *
86 * This is only for internal list manipulation where we know
87 * the prev/next entries already!
88 */
__list_del(struct list_head * prev,struct list_head * next)89 static __inline__ void __list_del(struct list_head * prev,
90 struct list_head * next)
91 {
92 next->prev = prev;
93 prev->next = next;
94 }
95
96 /**
97 * list_del - deletes entry from list.
98 * @param entry the element to delete from the list.
99 * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
100 */
list_del(struct list_head * entry)101 static __inline__ void list_del(struct list_head * entry)
102 {
103 __list_del(entry->prev, entry->next);
104 }
105
106 /**
107 * list_del_init - deletes entry from list and reinitialize it.
108 * @param entry the element to delete from the list.
109 */
list_del_init(struct list_head * entry)110 static __inline__ void list_del_init(struct list_head * entry)
111 {
112 __list_del(entry->prev, entry->next);
113 list_init(entry);
114 }
115
116 /**
117 * list_empty - tests whether a list is empty
118 * @param head the list to test.
119 */
list_empty(struct list_head const * head)120 static __inline__ int list_empty(struct list_head const * head)
121 {
122 return head->next == head;
123 }
124
125 /**
126 * list_splice - join two lists
127 * @param list the new list to add.
128 * @param head the place to add it in the first list.
129 */
list_splice(struct list_head * list,struct list_head * head)130 static __inline__ void list_splice(struct list_head * list, struct list_head * head)
131 {
132 struct list_head * first = list->next;
133
134 if (first != list) {
135 struct list_head * last = list->prev;
136 struct list_head * at = head->next;
137
138 first->prev = head;
139 head->next = first;
140
141 last->next = at;
142 at->prev = last;
143 }
144 }
145
146 /**
147 * list_entry - get the struct for this entry
148 * @param ptr the &struct list_head pointer.
149 * @param type the type of the struct this is embedded in.
150 * @param member the name of the list_struct within the struct.
151 */
152 #define list_entry(ptr, type, member) \
153 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
154
155 /**
156 * list_for_each - iterate over a list
157 * @param pos the &struct list_head to use as a loop counter.
158 * @param head the head for your list.
159 */
160 #define list_for_each(pos, head) \
161 for (pos = (head)->next; pos != (head); pos = pos->next)
162
163 /**
164 * list_for_each_safe - iterate over a list safe against removal of list entry
165 * @param pos the &struct list_head to use as a loop counter.
166 * @param n another &struct list_head to use as temporary storage
167 * @param head the head for your list.
168 */
169 #define list_for_each_safe(pos, n, head) \
170 for (pos = (head)->next, n = pos->next; pos != (head); \
171 pos = n, n = pos->next)
172
173 #define LIST_HEAD_INIT(name) { &(name), &(name) }
174
175 #define LIST_HEAD(name) struct list_head name = LIST_HEAD_INIT(name)
176
177 #endif /* OP_LIST_H */
178