1#ifndef _LINUX_LIST_H 2#define _LINUX_LIST_H 3 4#if defined(__KERNEL__) || defined(_LVM_H_INCLUDE) 5 6#include <linux/prefetch.h> 7 8/* 9 * Simple doubly linked list implementation. 10 * 11 * Some of the internal functions ("__xxx") are useful when 12 * manipulating whole lists rather than single entries, as 13 * sometimes we already know the next/prev entries and we can 14 * generate better code by using them directly rather than 15 * using the generic single-entry routines. 16 */ 17 18struct list_head { 19 struct list_head *next, *prev; 20}; 21 22#define LIST_HEAD_INIT(name) { &(name), &(name) } 23 24#define LIST_HEAD(name) \ 25 struct list_head name = LIST_HEAD_INIT(name) 26 27#define INIT_LIST_HEAD(ptr) do { \ 28 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ 29} while (0) 30 31/* 32 * Insert a new entry between two known consecutive entries. 33 * 34 * This is only for internal list manipulation where we know 35 * the prev/next entries already! 36 */ 37static inline void __list_add(struct list_head *new, 38 struct list_head *prev, 39 struct list_head *next) 40{ 41 next->prev = new; 42 new->next = next; 43 new->prev = prev; 44 prev->next = new; 45} 46 47/** 48 * list_add - add a new entry 49 * @new: new entry to be added 50 * @head: list head to add it after 51 * 52 * Insert a new entry after the specified head. 53 * This is good for implementing stacks. 54 */ 55static inline void list_add(struct list_head *new, struct list_head *head) 56{ 57 __list_add(new, head, head->next); 58} 59 60/** 61 * list_add_tail - add a new entry 62 * @new: new entry to be added 63 * @head: list head to add it before 64 * 65 * Insert a new entry before the specified head. 66 * This is useful for implementing queues. 67 */ 68static inline void list_add_tail(struct list_head *new, struct list_head *head) 69{ 70 __list_add(new, head->prev, head); 71} 72 73/* 74 * Delete a list entry by making the prev/next entries 75 * point to each other. 76 * 77 * This is only for internal list manipulation where we know 78 * the prev/next entries already! 79 */ 80static inline void __list_del(struct list_head *prev, struct list_head *next) 81{ 82 next->prev = prev; 83 prev->next = next; 84} 85 86/** 87 * list_del - deletes entry from list. 88 * @entry: the element to delete from the list. 89 * Note: list_empty on entry does not return true after this, the entry is in an undefined state. 90 */ 91static inline void list_del(struct list_head *entry) 92{ 93 __list_del(entry->prev, entry->next); 94 entry->next = (void *) 0; 95 entry->prev = (void *) 0; 96} 97 98/** 99 * list_del_init - deletes entry from list and reinitialize it. 100 * @entry: the element to delete from the list. 101 */ 102static inline void list_del_init(struct list_head *entry) 103{ 104 __list_del(entry->prev, entry->next); 105 INIT_LIST_HEAD(entry); 106} 107 108/** 109 * list_move - delete from one list and add as another's head 110 * @list: the entry to move 111 * @head: the head that will precede our entry 112 */ 113static inline void list_move(struct list_head *list, struct list_head *head) 114{ 115 __list_del(list->prev, list->next); 116 list_add(list, head); 117} 118 119/** 120 * list_move_tail - delete from one list and add as another's tail 121 * @list: the entry to move 122 * @head: the head that will follow our entry 123 */ 124static inline void list_move_tail(struct list_head *list, 125 struct list_head *head) 126{ 127 __list_del(list->prev, list->next); 128 list_add_tail(list, head); 129} 130 131/** 132 * list_empty - tests whether a list is empty 133 * @head: the list to test. 134 */ 135static inline int list_empty(struct list_head *head) 136{ 137 return head->next == head; 138} 139 140static inline void __list_splice(struct list_head *list, 141 struct list_head *head) 142{ 143 struct list_head *first = list->next; 144 struct list_head *last = list->prev; 145 struct list_head *at = head->next; 146 147 first->prev = head; 148 head->next = first; 149 150 last->next = at; 151 at->prev = last; 152} 153 154/** 155 * list_splice - join two lists 156 * @list: the new list to add. 157 * @head: the place to add it in the first list. 158 */ 159static inline void list_splice(struct list_head *list, struct list_head *head) 160{ 161 if (!list_empty(list)) 162 __list_splice(list, head); 163} 164 165/** 166 * list_splice_init - join two lists and reinitialise the emptied list. 167 * @list: the new list to add. 168 * @head: the place to add it in the first list. 169 * 170 * The list at @list is reinitialised 171 */ 172static inline void list_splice_init(struct list_head *list, 173 struct list_head *head) 174{ 175 if (!list_empty(list)) { 176 __list_splice(list, head); 177 INIT_LIST_HEAD(list); 178 } 179} 180 181/** 182 * list_entry - get the struct for this entry 183 * @ptr: the &struct list_head pointer. 184 * @type: the type of the struct this is embedded in. 185 * @member: the name of the list_struct within the struct. 186 */ 187#define list_entry(ptr, type, member) \ 188 ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) 189 190/** 191 * list_for_each - iterate over a list 192 * @pos: the &struct list_head to use as a loop counter. 193 * @head: the head for your list. 194 */ 195#define list_for_each(pos, head) \ 196 for (pos = (head)->next, prefetch(pos->next); pos != (head); \ 197 pos = pos->next, prefetch(pos->next)) 198/** 199 * list_for_each_prev - iterate over a list backwards 200 * @pos: the &struct list_head to use as a loop counter. 201 * @head: the head for your list. 202 */ 203#define list_for_each_prev(pos, head) \ 204 for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ 205 pos = pos->prev, prefetch(pos->prev)) 206 207/** 208 * list_for_each_safe - iterate over a list safe against removal of list entry 209 * @pos: the &struct list_head to use as a loop counter. 210 * @n: another &struct list_head to use as temporary storage 211 * @head: the head for your list. 212 */ 213#define list_for_each_safe(pos, n, head) \ 214 for (pos = (head)->next, n = pos->next; pos != (head); \ 215 pos = n, n = pos->next) 216 217/** 218 * list_for_each_entry - iterate over list of given type 219 * @pos: the type * to use as a loop counter. 220 * @head: the head for your list. 221 * @member: the name of the list_struct within the struct. 222 */ 223#define list_for_each_entry(pos, head, member) \ 224 for (pos = list_entry((head)->next, typeof(*pos), member), \ 225 prefetch(pos->member.next); \ 226 &pos->member != (head); \ 227 pos = list_entry(pos->member.next, typeof(*pos), member), \ 228 prefetch(pos->member.next)) 229 230#endif /* __KERNEL__ || _LVM_H_INCLUDE */ 231 232#endif 233