list.h (8095B)
1 /* 2 * Copied from the Linux kernel source tree, version 2.6.0-test1. 3 * 4 * Licensed under the GPL v2 as per the whole kernel source tree. 5 * 6 */ 7 8 #ifndef _LIST_H 9 #define _LIST_H 10 11 /** 12 * container_of - cast a member of a structure out to the containing structure 13 * 14 * @ptr: the pointer to the member. 15 * @type: the type of the container struct this is embedded in. 16 * @member: the name of the member within the struct. 17 * 18 */ 19 #define container_of(ptr, type, member) ({ \ 20 const typeof( ((type *)0)->member ) *__mptr = (ptr); \ 21 (type *)( (char *)__mptr - offsetof(type,member) );}) 22 23 /* 24 * These are non-NULL pointers that will result in page faults 25 * under normal circumstances, used to verify that nobody uses 26 * non-initialized list entries. 27 */ 28 #define LIST_POISON1 ((void *) 0x00100100) 29 #define LIST_POISON2 ((void *) 0x00200200) 30 31 /* 32 * Simple doubly linked list implementation. 33 * 34 * Some of the internal functions ("__xxx") are useful when 35 * manipulating whole lists rather than single entries, as 36 * sometimes we already know the next/prev entries and we can 37 * generate better code by using them directly rather than 38 * using the generic single-entry routines. 39 */ 40 41 struct list_head { 42 struct list_head *next, *prev; 43 }; 44 45 #define LIST_HEAD_INIT(name) { &(name), &(name) } 46 47 #define LIST_HEAD(name) \ 48 struct list_head name = LIST_HEAD_INIT(name) 49 50 #define INIT_LIST_HEAD(ptr) do { \ 51 (ptr)->next = (ptr); (ptr)->prev = (ptr); \ 52 } while (0) 53 54 /* 55 * Insert a new entry between two known consecutive entries. 56 * 57 * This is only for internal list manipulation where we know 58 * the prev/next entries already! 59 */ 60 static inline void __list_add(struct list_head *new, 61 struct list_head *prev, 62 struct list_head *next) 63 { 64 next->prev = new; 65 new->next = next; 66 new->prev = prev; 67 prev->next = new; 68 } 69 70 /** 71 * list_add - add a new entry 72 * @new: new entry to be added 73 * @head: list head to add it after 74 * 75 * Insert a new entry after the specified head. 76 * This is good for implementing stacks. 77 */ 78 static inline void list_add(struct list_head *new, struct list_head *head) 79 { 80 __list_add(new, head, head->next); 81 } 82 83 /** 84 * list_add_tail - add a new entry 85 * @new: new entry to be added 86 * @head: list head to add it before 87 * 88 * Insert a new entry before the specified head. 89 * This is useful for implementing queues. 90 */ 91 static inline void list_add_tail(struct list_head *new, struct list_head *head) 92 { 93 __list_add(new, head->prev, head); 94 } 95 96 /* 97 * Delete a list entry by making the prev/next entries 98 * point to each other. 99 * 100 * This is only for internal list manipulation where we know 101 * the prev/next entries already! 102 */ 103 static inline void __list_del(struct list_head * prev, struct list_head * next) 104 { 105 next->prev = prev; 106 prev->next = next; 107 } 108 109 /** 110 * list_del - deletes entry from list. 111 * @entry: the element to delete from the list. 112 * Note: list_empty on entry does not return true after this, the entry is 113 * in an undefined state. 114 */ 115 static inline void list_del(struct list_head *entry) 116 { 117 __list_del(entry->prev, entry->next); 118 entry->next = LIST_POISON1; 119 entry->prev = LIST_POISON2; 120 } 121 122 /** 123 * list_del_init - deletes entry from list and reinitialize it. 124 * @entry: the element to delete from the list. 125 */ 126 static inline void list_del_init(struct list_head *entry) 127 { 128 __list_del(entry->prev, entry->next); 129 INIT_LIST_HEAD(entry); 130 } 131 132 /** 133 * list_move - delete from one list and add as another's head 134 * @list: the entry to move 135 * @head: the head that will precede our entry 136 */ 137 static inline void list_move(struct list_head *list, struct list_head *head) 138 { 139 __list_del(list->prev, list->next); 140 list_add(list, head); 141 } 142 143 /** 144 * list_move_tail - delete from one list and add as another's tail 145 * @list: the entry to move 146 * @head: the head that will follow our entry 147 */ 148 static inline void list_move_tail(struct list_head *list, 149 struct list_head *head) 150 { 151 __list_del(list->prev, list->next); 152 list_add_tail(list, head); 153 } 154 155 /** 156 * list_empty - tests whether a list is empty 157 * @head: the list to test. 158 */ 159 static inline int list_empty(struct list_head *head) 160 { 161 return head->next == head; 162 } 163 164 static inline void __list_splice(struct list_head *list, 165 struct list_head *head) 166 { 167 struct list_head *first = list->next; 168 struct list_head *last = list->prev; 169 struct list_head *at = head->next; 170 171 first->prev = head; 172 head->next = first; 173 174 last->next = at; 175 at->prev = last; 176 } 177 178 /** 179 * list_splice - join two lists 180 * @list: the new list to add. 181 * @head: the place to add it in the first list. 182 */ 183 static inline void list_splice(struct list_head *list, struct list_head *head) 184 { 185 if (!list_empty(list)) 186 __list_splice(list, head); 187 } 188 189 /** 190 * list_splice_init - join two lists and reinitialise the emptied list. 191 * @list: the new list to add. 192 * @head: the place to add it in the first list. 193 * 194 * The list at @list is reinitialised 195 */ 196 static inline void list_splice_init(struct list_head *list, 197 struct list_head *head) 198 { 199 if (!list_empty(list)) { 200 __list_splice(list, head); 201 INIT_LIST_HEAD(list); 202 } 203 } 204 205 /** 206 * list_entry - get the struct for this entry 207 * @ptr: the &struct list_head pointer. 208 * @type: the type of the struct this is embedded in. 209 * @member: the name of the list_struct within the struct. 210 */ 211 #define list_entry(ptr, type, member) \ 212 container_of(ptr, type, member) 213 214 /** 215 * list_for_each - iterate over a list 216 * @pos: the &struct list_head to use as a loop counter. 217 * @head: the head for your list. 218 */ 219 #define list_for_each(pos, head) \ 220 for (pos = (head)->next; pos != (head); \ 221 pos = pos->next) 222 223 /** 224 * __list_for_each - iterate over a list 225 * @pos: the &struct list_head to use as a loop counter. 226 * @head: the head for your list. 227 * 228 * This variant differs from list_for_each() in that it's the 229 * simplest possible list iteration code. 230 * Use this for code that knows the list to be very short (empty 231 * or 1 entry) most of the time. 232 */ 233 #define __list_for_each(pos, head) \ 234 for (pos = (head)->next; pos != (head); pos = pos->next) 235 236 /** 237 * list_for_each_prev - iterate over a list backwards 238 * @pos: the &struct list_head to use as a loop counter. 239 * @head: the head for your list. 240 */ 241 #define list_for_each_prev(pos, head) \ 242 for (pos = (head)->prev; pos != (head); pos = pos->prev) 243 244 /** 245 * list_for_each_safe - iterate over a list safe against removal of list entry 246 * @pos: the &struct list_head to use as a loop counter. 247 * @n: another &struct list_head to use as temporary storage 248 * @head: the head for your list. 249 */ 250 #define list_for_each_safe(pos, n, head) \ 251 for (pos = (head)->next, n = pos->next; pos != (head); \ 252 pos = n, n = pos->next) 253 254 /** 255 * list_for_each_entry - iterate over list of given type 256 * @pos: the type * to use as a loop counter. 257 * @head: the head for your list. 258 * @member: the name of the list_struct within the struct. 259 */ 260 #define list_for_each_entry(pos, head, member) \ 261 for (pos = list_entry((head)->next, typeof(*pos), member); \ 262 &pos->member != (head); \ 263 pos = list_entry(pos->member.next, typeof(*pos), member)) 264 265 /** 266 * list_for_each_entry_reverse - iterate backwards over list of given type. 267 * @pos: the type * to use as a loop counter. 268 * @head: the head for your list. 269 * @member: the name of the list_struct within the struct. 270 */ 271 #define list_for_each_entry_reverse(pos, head, member) \ 272 for (pos = list_entry((head)->prev, typeof(*pos), member); \ 273 &pos->member != (head); \ 274 pos = list_entry(pos->member.prev, typeof(*pos), member)) 275 276 /** 277 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry 278 * @pos: the type * to use as a loop counter. 279 * @n: another type * to use as temporary storage 280 * @head: the head for your list. 281 * @member: the name of the list_struct within the struct. 282 */ 283 #define list_for_each_entry_safe(pos, n, head, member) \ 284 for (pos = list_entry((head)->next, typeof(*pos), member), \ 285 n = list_entry(pos->member.next, typeof(*pos), member); \ 286 &pos->member != (head); \ 287 pos = n, n = list_entry(n->member.next, typeof(*n), member)) 288 289 #endif /* _LIST_H */