Harald Welte | aae69be | 2004-08-29 23:32:14 +0000 | [diff] [blame] | 1 | #ifndef _LINUX_LIST_H |
| 2 | #define _LINUX_LIST_H |
| 3 | |
| 4 | #undef offsetof |
| 5 | #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) |
| 6 | |
| 7 | /** |
| 8 | * container_of - cast a member of a structure out to the containing structure |
| 9 | * |
| 10 | * @ptr: the pointer to the member. |
| 11 | * @type: the type of the container struct this is embedded in. |
| 12 | * @member: the name of the member within the struct. |
| 13 | * |
| 14 | */ |
| 15 | #define container_of(ptr, type, member) ({ \ |
| 16 | const typeof( ((type *)0)->member ) *__mptr = (ptr); \ |
| 17 | (type *)( (char *)__mptr - offsetof(type,member) );}) |
| 18 | |
| 19 | /* |
| 20 | * Check at compile time that something is of a particular type. |
| 21 | * Always evaluates to 1 so you may use it easily in comparisons. |
| 22 | */ |
| 23 | #define typecheck(type,x) \ |
| 24 | ({ type __dummy; \ |
| 25 | typeof(x) __dummy2; \ |
| 26 | (void)(&__dummy == &__dummy2); \ |
| 27 | 1; \ |
| 28 | }) |
| 29 | |
| 30 | #define prefetch(x) 1 |
| 31 | |
| 32 | /* empty define to make this work in userspace -HW */ |
| 33 | #define smp_wmb() |
| 34 | |
| 35 | /* |
| 36 | * These are non-NULL pointers that will result in page faults |
| 37 | * under normal circumstances, used to verify that nobody uses |
| 38 | * non-initialized list entries. |
| 39 | */ |
| 40 | #define LIST_POISON1 ((void *) 0x00100100) |
| 41 | #define LIST_POISON2 ((void *) 0x00200200) |
| 42 | |
| 43 | /* |
| 44 | * Simple doubly linked list implementation. |
| 45 | * |
| 46 | * Some of the internal functions ("__xxx") are useful when |
| 47 | * manipulating whole lists rather than single entries, as |
| 48 | * sometimes we already know the next/prev entries and we can |
| 49 | * generate better code by using them directly rather than |
| 50 | * using the generic single-entry routines. |
| 51 | */ |
| 52 | |
| 53 | struct list_head { |
| 54 | struct list_head *next, *prev; |
| 55 | }; |
| 56 | |
| 57 | #define LIST_HEAD_INIT(name) { &(name), &(name) } |
| 58 | |
| 59 | #define LIST_HEAD(name) \ |
| 60 | struct list_head name = LIST_HEAD_INIT(name) |
| 61 | |
| 62 | #define INIT_LIST_HEAD(ptr) do { \ |
| 63 | (ptr)->next = (ptr); (ptr)->prev = (ptr); \ |
| 64 | } while (0) |
| 65 | |
| 66 | /* |
| 67 | * Insert a new entry between two known consecutive entries. |
| 68 | * |
| 69 | * This is only for internal list manipulation where we know |
| 70 | * the prev/next entries already! |
| 71 | */ |
| 72 | static inline void __list_add(struct list_head *new, |
| 73 | struct list_head *prev, |
| 74 | struct list_head *next) |
| 75 | { |
| 76 | next->prev = new; |
| 77 | new->next = next; |
| 78 | new->prev = prev; |
| 79 | prev->next = new; |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * list_add - add a new entry |
| 84 | * @new: new entry to be added |
| 85 | * @head: list head to add it after |
| 86 | * |
| 87 | * Insert a new entry after the specified head. |
| 88 | * This is good for implementing stacks. |
| 89 | */ |
| 90 | static inline void list_add(struct list_head *new, struct list_head *head) |
| 91 | { |
| 92 | __list_add(new, head, head->next); |
| 93 | } |
| 94 | |
| 95 | /** |
| 96 | * list_add_tail - add a new entry |
| 97 | * @new: new entry to be added |
| 98 | * @head: list head to add it before |
| 99 | * |
| 100 | * Insert a new entry before the specified head. |
| 101 | * This is useful for implementing queues. |
| 102 | */ |
| 103 | static inline void list_add_tail(struct list_head *new, struct list_head *head) |
| 104 | { |
| 105 | __list_add(new, head->prev, head); |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | * Insert a new entry between two known consecutive entries. |
| 110 | * |
| 111 | * This is only for internal list manipulation where we know |
| 112 | * the prev/next entries already! |
| 113 | */ |
| 114 | static inline void __list_add_rcu(struct list_head * new, |
| 115 | struct list_head * prev, struct list_head * next) |
| 116 | { |
| 117 | new->next = next; |
| 118 | new->prev = prev; |
| 119 | smp_wmb(); |
| 120 | next->prev = new; |
| 121 | prev->next = new; |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * list_add_rcu - add a new entry to rcu-protected list |
| 126 | * @new: new entry to be added |
| 127 | * @head: list head to add it after |
| 128 | * |
| 129 | * Insert a new entry after the specified head. |
| 130 | * This is good for implementing stacks. |
| 131 | * |
| 132 | * The caller must take whatever precautions are necessary |
| 133 | * (such as holding appropriate locks) to avoid racing |
| 134 | * with another list-mutation primitive, such as list_add_rcu() |
| 135 | * or list_del_rcu(), running on this same list. |
| 136 | * However, it is perfectly legal to run concurrently with |
| 137 | * the _rcu list-traversal primitives, such as |
| 138 | * list_for_each_entry_rcu(). |
| 139 | */ |
| 140 | static inline void list_add_rcu(struct list_head *new, struct list_head *head) |
| 141 | { |
| 142 | __list_add_rcu(new, head, head->next); |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * list_add_tail_rcu - add a new entry to rcu-protected list |
| 147 | * @new: new entry to be added |
| 148 | * @head: list head to add it before |
| 149 | * |
| 150 | * Insert a new entry before the specified head. |
| 151 | * This is useful for implementing queues. |
| 152 | * |
| 153 | * The caller must take whatever precautions are necessary |
| 154 | * (such as holding appropriate locks) to avoid racing |
| 155 | * with another list-mutation primitive, such as list_add_tail_rcu() |
| 156 | * or list_del_rcu(), running on this same list. |
| 157 | * However, it is perfectly legal to run concurrently with |
| 158 | * the _rcu list-traversal primitives, such as |
| 159 | * list_for_each_entry_rcu(). |
| 160 | */ |
| 161 | static inline void list_add_tail_rcu(struct list_head *new, |
| 162 | struct list_head *head) |
| 163 | { |
| 164 | __list_add_rcu(new, head->prev, head); |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Delete a list entry by making the prev/next entries |
| 169 | * point to each other. |
| 170 | * |
| 171 | * This is only for internal list manipulation where we know |
| 172 | * the prev/next entries already! |
| 173 | */ |
| 174 | static inline void __list_del(struct list_head * prev, struct list_head * next) |
| 175 | { |
| 176 | next->prev = prev; |
| 177 | prev->next = next; |
| 178 | } |
| 179 | |
| 180 | /** |
| 181 | * list_del - deletes entry from list. |
| 182 | * @entry: the element to delete from the list. |
| 183 | * Note: list_empty on entry does not return true after this, the entry is |
| 184 | * in an undefined state. |
| 185 | */ |
| 186 | static inline void list_del(struct list_head *entry) |
| 187 | { |
| 188 | __list_del(entry->prev, entry->next); |
| 189 | entry->next = LIST_POISON1; |
| 190 | entry->prev = LIST_POISON2; |
| 191 | } |
| 192 | |
| 193 | /** |
| 194 | * list_del_rcu - deletes entry from list without re-initialization |
| 195 | * @entry: the element to delete from the list. |
| 196 | * |
| 197 | * Note: list_empty on entry does not return true after this, |
| 198 | * the entry is in an undefined state. It is useful for RCU based |
| 199 | * lockfree traversal. |
| 200 | * |
| 201 | * In particular, it means that we can not poison the forward |
| 202 | * pointers that may still be used for walking the list. |
| 203 | * |
| 204 | * The caller must take whatever precautions are necessary |
| 205 | * (such as holding appropriate locks) to avoid racing |
| 206 | * with another list-mutation primitive, such as list_del_rcu() |
| 207 | * or list_add_rcu(), running on this same list. |
| 208 | * However, it is perfectly legal to run concurrently with |
| 209 | * the _rcu list-traversal primitives, such as |
| 210 | * list_for_each_entry_rcu(). |
| 211 | * |
| 212 | * Note that the caller is not permitted to immediately free |
| 213 | * the newly deleted entry. Instead, either synchronize_kernel() |
| 214 | * or call_rcu() must be used to defer freeing until an RCU |
| 215 | * grace period has elapsed. |
| 216 | */ |
| 217 | static inline void list_del_rcu(struct list_head *entry) |
| 218 | { |
| 219 | __list_del(entry->prev, entry->next); |
| 220 | entry->prev = LIST_POISON2; |
| 221 | } |
| 222 | |
| 223 | /** |
| 224 | * list_del_init - deletes entry from list and reinitialize it. |
| 225 | * @entry: the element to delete from the list. |
| 226 | */ |
| 227 | static inline void list_del_init(struct list_head *entry) |
| 228 | { |
| 229 | __list_del(entry->prev, entry->next); |
| 230 | INIT_LIST_HEAD(entry); |
| 231 | } |
| 232 | |
| 233 | /** |
| 234 | * list_move - delete from one list and add as another's head |
| 235 | * @list: the entry to move |
| 236 | * @head: the head that will precede our entry |
| 237 | */ |
| 238 | static inline void list_move(struct list_head *list, struct list_head *head) |
| 239 | { |
| 240 | __list_del(list->prev, list->next); |
| 241 | list_add(list, head); |
| 242 | } |
| 243 | |
| 244 | /** |
| 245 | * list_move_tail - delete from one list and add as another's tail |
| 246 | * @list: the entry to move |
| 247 | * @head: the head that will follow our entry |
| 248 | */ |
| 249 | static inline void list_move_tail(struct list_head *list, |
| 250 | struct list_head *head) |
| 251 | { |
| 252 | __list_del(list->prev, list->next); |
| 253 | list_add_tail(list, head); |
| 254 | } |
| 255 | |
| 256 | /** |
| 257 | * list_empty - tests whether a list is empty |
| 258 | * @head: the list to test. |
| 259 | */ |
| 260 | static inline int list_empty(const struct list_head *head) |
| 261 | { |
| 262 | return head->next == head; |
| 263 | } |
| 264 | |
| 265 | /** |
| 266 | * list_empty_careful - tests whether a list is |
| 267 | * empty _and_ checks that no other CPU might be |
| 268 | * in the process of still modifying either member |
| 269 | * |
| 270 | * NOTE: using list_empty_careful() without synchronization |
| 271 | * can only be safe if the only activity that can happen |
| 272 | * to the list entry is list_del_init(). Eg. it cannot be used |
| 273 | * if another CPU could re-list_add() it. |
| 274 | * |
| 275 | * @head: the list to test. |
| 276 | */ |
| 277 | static inline int list_empty_careful(const struct list_head *head) |
| 278 | { |
| 279 | struct list_head *next = head->next; |
| 280 | return (next == head) && (next == head->prev); |
| 281 | } |
| 282 | |
| 283 | static inline void __list_splice(struct list_head *list, |
| 284 | struct list_head *head) |
| 285 | { |
| 286 | struct list_head *first = list->next; |
| 287 | struct list_head *last = list->prev; |
| 288 | struct list_head *at = head->next; |
| 289 | |
| 290 | first->prev = head; |
| 291 | head->next = first; |
| 292 | |
| 293 | last->next = at; |
| 294 | at->prev = last; |
| 295 | } |
| 296 | |
| 297 | /** |
| 298 | * list_splice - join two lists |
| 299 | * @list: the new list to add. |
| 300 | * @head: the place to add it in the first list. |
| 301 | */ |
| 302 | static inline void list_splice(struct list_head *list, struct list_head *head) |
| 303 | { |
| 304 | if (!list_empty(list)) |
| 305 | __list_splice(list, head); |
| 306 | } |
| 307 | |
| 308 | /** |
| 309 | * list_splice_init - join two lists and reinitialise the emptied list. |
| 310 | * @list: the new list to add. |
| 311 | * @head: the place to add it in the first list. |
| 312 | * |
| 313 | * The list at @list is reinitialised |
| 314 | */ |
| 315 | static inline void list_splice_init(struct list_head *list, |
| 316 | struct list_head *head) |
| 317 | { |
| 318 | if (!list_empty(list)) { |
| 319 | __list_splice(list, head); |
| 320 | INIT_LIST_HEAD(list); |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | /** |
| 325 | * list_entry - get the struct for this entry |
| 326 | * @ptr: the &struct list_head pointer. |
| 327 | * @type: the type of the struct this is embedded in. |
| 328 | * @member: the name of the list_struct within the struct. |
| 329 | */ |
| 330 | #define list_entry(ptr, type, member) \ |
| 331 | container_of(ptr, type, member) |
| 332 | |
| 333 | /** |
| 334 | * list_for_each - iterate over a list |
| 335 | * @pos: the &struct list_head to use as a loop counter. |
| 336 | * @head: the head for your list. |
| 337 | */ |
| 338 | #define list_for_each(pos, head) \ |
| 339 | for (pos = (head)->next, prefetch(pos->next); pos != (head); \ |
| 340 | pos = pos->next, prefetch(pos->next)) |
| 341 | |
| 342 | /** |
| 343 | * __list_for_each - iterate over a list |
| 344 | * @pos: the &struct list_head to use as a loop counter. |
| 345 | * @head: the head for your list. |
| 346 | * |
| 347 | * This variant differs from list_for_each() in that it's the |
| 348 | * simplest possible list iteration code, no prefetching is done. |
| 349 | * Use this for code that knows the list to be very short (empty |
| 350 | * or 1 entry) most of the time. |
| 351 | */ |
| 352 | #define __list_for_each(pos, head) \ |
| 353 | for (pos = (head)->next; pos != (head); pos = pos->next) |
| 354 | |
| 355 | /** |
| 356 | * list_for_each_prev - iterate over a list backwards |
| 357 | * @pos: the &struct list_head to use as a loop counter. |
| 358 | * @head: the head for your list. |
| 359 | */ |
| 360 | #define list_for_each_prev(pos, head) \ |
| 361 | for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ |
| 362 | pos = pos->prev, prefetch(pos->prev)) |
| 363 | |
| 364 | /** |
| 365 | * list_for_each_safe - iterate over a list safe against removal of list entry |
| 366 | * @pos: the &struct list_head to use as a loop counter. |
| 367 | * @n: another &struct list_head to use as temporary storage |
| 368 | * @head: the head for your list. |
| 369 | */ |
| 370 | #define list_for_each_safe(pos, n, head) \ |
| 371 | for (pos = (head)->next, n = pos->next; pos != (head); \ |
| 372 | pos = n, n = pos->next) |
| 373 | |
| 374 | /** |
| 375 | * list_for_each_entry - iterate over list of given type |
| 376 | * @pos: the type * to use as a loop counter. |
| 377 | * @head: the head for your list. |
| 378 | * @member: the name of the list_struct within the struct. |
| 379 | */ |
| 380 | #define list_for_each_entry(pos, head, member) \ |
| 381 | for (pos = list_entry((head)->next, typeof(*pos), member), \ |
| 382 | prefetch(pos->member.next); \ |
| 383 | &pos->member != (head); \ |
| 384 | pos = list_entry(pos->member.next, typeof(*pos), member), \ |
| 385 | prefetch(pos->member.next)) |
| 386 | |
| 387 | /** |
| 388 | * list_for_each_entry_reverse - iterate backwards over list of given type. |
| 389 | * @pos: the type * to use as a loop counter. |
| 390 | * @head: the head for your list. |
| 391 | * @member: the name of the list_struct within the struct. |
| 392 | */ |
| 393 | #define list_for_each_entry_reverse(pos, head, member) \ |
| 394 | for (pos = list_entry((head)->prev, typeof(*pos), member), \ |
| 395 | prefetch(pos->member.prev); \ |
| 396 | &pos->member != (head); \ |
| 397 | pos = list_entry(pos->member.prev, typeof(*pos), member), \ |
| 398 | prefetch(pos->member.prev)) |
| 399 | |
| 400 | /** |
| 401 | * list_prepare_entry - prepare a pos entry for use as a start point in |
| 402 | * list_for_each_entry_continue |
| 403 | * @pos: the type * to use as a start point |
| 404 | * @head: the head of the list |
| 405 | * @member: the name of the list_struct within the struct. |
| 406 | */ |
| 407 | #define list_prepare_entry(pos, head, member) \ |
| 408 | ((pos) ? : list_entry(head, typeof(*pos), member)) |
| 409 | |
| 410 | /** |
| 411 | * list_for_each_entry_continue - iterate over list of given type |
| 412 | * continuing after existing point |
| 413 | * @pos: the type * to use as a loop counter. |
| 414 | * @head: the head for your list. |
| 415 | * @member: the name of the list_struct within the struct. |
| 416 | */ |
| 417 | #define list_for_each_entry_continue(pos, head, member) \ |
| 418 | for (pos = list_entry(pos->member.next, typeof(*pos), member), \ |
| 419 | prefetch(pos->member.next); \ |
| 420 | &pos->member != (head); \ |
| 421 | pos = list_entry(pos->member.next, typeof(*pos), member), \ |
| 422 | prefetch(pos->member.next)) |
| 423 | |
| 424 | /** |
| 425 | * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry |
| 426 | * @pos: the type * to use as a loop counter. |
| 427 | * @n: another type * to use as temporary storage |
| 428 | * @head: the head for your list. |
| 429 | * @member: the name of the list_struct within the struct. |
| 430 | */ |
| 431 | #define list_for_each_entry_safe(pos, n, head, member) \ |
| 432 | for (pos = list_entry((head)->next, typeof(*pos), member), \ |
| 433 | n = list_entry(pos->member.next, typeof(*pos), member); \ |
| 434 | &pos->member != (head); \ |
| 435 | pos = n, n = list_entry(n->member.next, typeof(*n), member)) |
| 436 | |
| 437 | /** |
| 438 | * list_for_each_rcu - iterate over an rcu-protected list |
| 439 | * @pos: the &struct list_head to use as a loop counter. |
| 440 | * @head: the head for your list. |
| 441 | * |
| 442 | * This list-traversal primitive may safely run concurrently with |
| 443 | * the _rcu list-mutation primitives such as list_add_rcu() |
| 444 | * as long as the traversal is guarded by rcu_read_lock(). |
| 445 | */ |
| 446 | #define list_for_each_rcu(pos, head) \ |
| 447 | for (pos = (head)->next, prefetch(pos->next); pos != (head); \ |
| 448 | pos = pos->next, ({ smp_read_barrier_depends(); 0;}), prefetch(pos->next)) |
| 449 | |
| 450 | #define __list_for_each_rcu(pos, head) \ |
| 451 | for (pos = (head)->next; pos != (head); \ |
| 452 | pos = pos->next, ({ smp_read_barrier_depends(); 0;})) |
| 453 | |
| 454 | /** |
| 455 | * list_for_each_safe_rcu - iterate over an rcu-protected list safe |
| 456 | * against removal of list entry |
| 457 | * @pos: the &struct list_head to use as a loop counter. |
| 458 | * @n: another &struct list_head to use as temporary storage |
| 459 | * @head: the head for your list. |
| 460 | * |
| 461 | * This list-traversal primitive may safely run concurrently with |
| 462 | * the _rcu list-mutation primitives such as list_add_rcu() |
| 463 | * as long as the traversal is guarded by rcu_read_lock(). |
| 464 | */ |
| 465 | #define list_for_each_safe_rcu(pos, n, head) \ |
| 466 | for (pos = (head)->next, n = pos->next; pos != (head); \ |
| 467 | pos = n, ({ smp_read_barrier_depends(); 0;}), n = pos->next) |
| 468 | |
| 469 | /** |
| 470 | * list_for_each_entry_rcu - iterate over rcu list of given type |
| 471 | * @pos: the type * to use as a loop counter. |
| 472 | * @head: the head for your list. |
| 473 | * @member: the name of the list_struct within the struct. |
| 474 | * |
| 475 | * This list-traversal primitive may safely run concurrently with |
| 476 | * the _rcu list-mutation primitives such as list_add_rcu() |
| 477 | * as long as the traversal is guarded by rcu_read_lock(). |
| 478 | */ |
| 479 | #define list_for_each_entry_rcu(pos, head, member) \ |
| 480 | for (pos = list_entry((head)->next, typeof(*pos), member), \ |
| 481 | prefetch(pos->member.next); \ |
| 482 | &pos->member != (head); \ |
| 483 | pos = list_entry(pos->member.next, typeof(*pos), member), \ |
| 484 | ({ smp_read_barrier_depends(); 0;}), \ |
| 485 | prefetch(pos->member.next)) |
| 486 | |
| 487 | |
| 488 | /** |
| 489 | * list_for_each_continue_rcu - iterate over an rcu-protected list |
| 490 | * continuing after existing point. |
| 491 | * @pos: the &struct list_head to use as a loop counter. |
| 492 | * @head: the head for your list. |
| 493 | * |
| 494 | * This list-traversal primitive may safely run concurrently with |
| 495 | * the _rcu list-mutation primitives such as list_add_rcu() |
| 496 | * as long as the traversal is guarded by rcu_read_lock(). |
| 497 | */ |
| 498 | #define list_for_each_continue_rcu(pos, head) \ |
| 499 | for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \ |
| 500 | (pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next)) |
| 501 | |
| 502 | /* |
| 503 | * Double linked lists with a single pointer list head. |
| 504 | * Mostly useful for hash tables where the two pointer list head is |
| 505 | * too wasteful. |
| 506 | * You lose the ability to access the tail in O(1). |
| 507 | */ |
| 508 | |
| 509 | struct hlist_head { |
| 510 | struct hlist_node *first; |
| 511 | }; |
| 512 | |
| 513 | struct hlist_node { |
| 514 | struct hlist_node *next, **pprev; |
| 515 | }; |
| 516 | |
| 517 | #define HLIST_HEAD_INIT { .first = NULL } |
| 518 | #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } |
| 519 | #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) |
| 520 | #define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL) |
| 521 | |
| 522 | static inline int hlist_unhashed(const struct hlist_node *h) |
| 523 | { |
| 524 | return !h->pprev; |
| 525 | } |
| 526 | |
| 527 | static inline int hlist_empty(const struct hlist_head *h) |
| 528 | { |
| 529 | return !h->first; |
| 530 | } |
| 531 | |
| 532 | static inline void __hlist_del(struct hlist_node *n) |
| 533 | { |
| 534 | struct hlist_node *next = n->next; |
| 535 | struct hlist_node **pprev = n->pprev; |
| 536 | *pprev = next; |
| 537 | if (next) |
| 538 | next->pprev = pprev; |
| 539 | } |
| 540 | |
| 541 | static inline void hlist_del(struct hlist_node *n) |
| 542 | { |
| 543 | __hlist_del(n); |
| 544 | n->next = LIST_POISON1; |
| 545 | n->pprev = LIST_POISON2; |
| 546 | } |
| 547 | |
| 548 | /** |
| 549 | * hlist_del_rcu - deletes entry from hash list without re-initialization |
| 550 | * @n: the element to delete from the hash list. |
| 551 | * |
| 552 | * Note: list_unhashed() on entry does not return true after this, |
| 553 | * the entry is in an undefined state. It is useful for RCU based |
| 554 | * lockfree traversal. |
| 555 | * |
| 556 | * In particular, it means that we can not poison the forward |
| 557 | * pointers that may still be used for walking the hash list. |
| 558 | * |
| 559 | * The caller must take whatever precautions are necessary |
| 560 | * (such as holding appropriate locks) to avoid racing |
| 561 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
| 562 | * or hlist_del_rcu(), running on this same list. |
| 563 | * However, it is perfectly legal to run concurrently with |
| 564 | * the _rcu list-traversal primitives, such as |
| 565 | * hlist_for_each_entry(). |
| 566 | */ |
| 567 | static inline void hlist_del_rcu(struct hlist_node *n) |
| 568 | { |
| 569 | __hlist_del(n); |
| 570 | n->pprev = LIST_POISON2; |
| 571 | } |
| 572 | |
| 573 | static inline void hlist_del_init(struct hlist_node *n) |
| 574 | { |
| 575 | if (n->pprev) { |
| 576 | __hlist_del(n); |
| 577 | INIT_HLIST_NODE(n); |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | #define hlist_del_rcu_init hlist_del_init |
| 582 | |
| 583 | static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) |
| 584 | { |
| 585 | struct hlist_node *first = h->first; |
| 586 | n->next = first; |
| 587 | if (first) |
| 588 | first->pprev = &n->next; |
| 589 | h->first = n; |
| 590 | n->pprev = &h->first; |
| 591 | } |
| 592 | |
| 593 | |
| 594 | /** |
| 595 | * hlist_add_head_rcu - adds the specified element to the specified hlist, |
| 596 | * while permitting racing traversals. |
| 597 | * @n: the element to add to the hash list. |
| 598 | * @h: the list to add to. |
| 599 | * |
| 600 | * The caller must take whatever precautions are necessary |
| 601 | * (such as holding appropriate locks) to avoid racing |
| 602 | * with another list-mutation primitive, such as hlist_add_head_rcu() |
| 603 | * or hlist_del_rcu(), running on this same list. |
| 604 | * However, it is perfectly legal to run concurrently with |
| 605 | * the _rcu list-traversal primitives, such as |
| 606 | * hlist_for_each_entry(), but only if smp_read_barrier_depends() |
| 607 | * is used to prevent memory-consistency problems on Alpha CPUs. |
| 608 | * Regardless of the type of CPU, the list-traversal primitive |
| 609 | * must be guarded by rcu_read_lock(). |
| 610 | * |
| 611 | * OK, so why don't we have an hlist_for_each_entry_rcu()??? |
| 612 | */ |
| 613 | static inline void hlist_add_head_rcu(struct hlist_node *n, |
| 614 | struct hlist_head *h) |
| 615 | { |
| 616 | struct hlist_node *first = h->first; |
| 617 | n->next = first; |
| 618 | n->pprev = &h->first; |
| 619 | smp_wmb(); |
| 620 | if (first) |
| 621 | first->pprev = &n->next; |
| 622 | h->first = n; |
| 623 | } |
| 624 | |
| 625 | /* next must be != NULL */ |
| 626 | static inline void hlist_add_before(struct hlist_node *n, |
| 627 | struct hlist_node *next) |
| 628 | { |
| 629 | n->pprev = next->pprev; |
| 630 | n->next = next; |
| 631 | next->pprev = &n->next; |
| 632 | *(n->pprev) = n; |
| 633 | } |
| 634 | |
| 635 | static inline void hlist_add_after(struct hlist_node *n, |
| 636 | struct hlist_node *next) |
| 637 | { |
| 638 | next->next = n->next; |
| 639 | n->next = next; |
| 640 | next->pprev = &n->next; |
| 641 | |
| 642 | if(next->next) |
| 643 | next->next->pprev = &next->next; |
| 644 | } |
| 645 | |
| 646 | #define hlist_entry(ptr, type, member) container_of(ptr,type,member) |
| 647 | |
| 648 | #define hlist_for_each(pos, head) \ |
| 649 | for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ |
| 650 | pos = pos->next) |
| 651 | |
| 652 | #define hlist_for_each_safe(pos, n, head) \ |
| 653 | for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ |
| 654 | pos = n) |
| 655 | |
| 656 | /** |
| 657 | * hlist_for_each_entry - iterate over list of given type |
| 658 | * @tpos: the type * to use as a loop counter. |
| 659 | * @pos: the &struct hlist_node to use as a loop counter. |
| 660 | * @head: the head for your list. |
| 661 | * @member: the name of the hlist_node within the struct. |
| 662 | */ |
| 663 | #define hlist_for_each_entry(tpos, pos, head, member) \ |
| 664 | for (pos = (head)->first; \ |
| 665 | pos && ({ prefetch(pos->next); 1;}) && \ |
| 666 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
| 667 | pos = pos->next) |
| 668 | |
| 669 | /** |
| 670 | * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point |
| 671 | * @tpos: the type * to use as a loop counter. |
| 672 | * @pos: the &struct hlist_node to use as a loop counter. |
| 673 | * @member: the name of the hlist_node within the struct. |
| 674 | */ |
| 675 | #define hlist_for_each_entry_continue(tpos, pos, member) \ |
| 676 | for (pos = (pos)->next; \ |
| 677 | pos && ({ prefetch(pos->next); 1;}) && \ |
| 678 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
| 679 | pos = pos->next) |
| 680 | |
| 681 | /** |
| 682 | * hlist_for_each_entry_from - iterate over a hlist continuing from existing point |
| 683 | * @tpos: the type * to use as a loop counter. |
| 684 | * @pos: the &struct hlist_node to use as a loop counter. |
| 685 | * @member: the name of the hlist_node within the struct. |
| 686 | */ |
| 687 | #define hlist_for_each_entry_from(tpos, pos, member) \ |
| 688 | for (; pos && ({ prefetch(pos->next); 1;}) && \ |
| 689 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
| 690 | pos = pos->next) |
| 691 | |
| 692 | /** |
| 693 | * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry |
| 694 | * @tpos: the type * to use as a loop counter. |
| 695 | * @pos: the &struct hlist_node to use as a loop counter. |
| 696 | * @n: another &struct hlist_node to use as temporary storage |
| 697 | * @head: the head for your list. |
| 698 | * @member: the name of the hlist_node within the struct. |
| 699 | */ |
| 700 | #define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ |
| 701 | for (pos = (head)->first; \ |
| 702 | pos && ({ n = pos->next; 1; }) && \ |
| 703 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
| 704 | pos = n) |
| 705 | |
| 706 | /** |
| 707 | * hlist_for_each_entry_rcu - iterate over rcu list of given type |
| 708 | * @pos: the type * to use as a loop counter. |
| 709 | * @pos: the &struct hlist_node to use as a loop counter. |
| 710 | * @head: the head for your list. |
| 711 | * @member: the name of the hlist_node within the struct. |
| 712 | * |
| 713 | * This list-traversal primitive may safely run concurrently with |
| 714 | * the _rcu list-mutation primitives such as hlist_add_rcu() |
| 715 | * as long as the traversal is guarded by rcu_read_lock(). |
| 716 | */ |
| 717 | #define hlist_for_each_entry_rcu(tpos, pos, head, member) \ |
| 718 | for (pos = (head)->first; \ |
| 719 | pos && ({ prefetch(pos->next); 1;}) && \ |
| 720 | ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ |
| 721 | pos = pos->next, ({ smp_read_barrier_depends(); 0; }) ) |
| 722 | |
| 723 | #endif |