list.h revision e6817ec1d8ab31fc7b01906e305f848542df6413
1#ifndef _LINUX_LIST_H 2#define _LINUX_LIST_H 3 4#include "poison.h" 5 6#define LIST_HEAD_INIT(name) { &(name), &(name) } 7 8#define LIST_HEAD(name) \ 9 struct list_head name = LIST_HEAD_INIT(name) 10 11static inline void INIT_LIST_HEAD(struct list_head *list) 12{ 13 list->next = list; 14 list->prev = list; 15} 16 17/* 18 * Insert a new entry between two known consecutive entries. 19 * 20 * This is only for internal list manipulation where we know 21 * the prev/next entries already! 22 */ 23#ifndef CONFIG_DEBUG_LIST 24static inline void __list_add(struct list_head *new, 25 struct list_head *prev, 26 struct list_head *next) 27{ 28 next->prev = new; 29 new->next = next; 30 new->prev = prev; 31 prev->next = new; 32} 33#else 34extern void __list_add(struct list_head *new, 35 struct list_head *prev, 36 struct list_head *next); 37#endif 38 39/** 40 * list_add - add a new entry 41 * @new: new entry to be added 42 * @head: list head to add it after 43 * 44 * Insert a new entry after the specified head. 45 * This is good for implementing stacks. 46 */ 47static inline void list_add(struct list_head *new, struct list_head *head) 48{ 49 __list_add(new, head, head->next); 50} 51 52 53/** 54 * list_add_tail - add a new entry 55 * @new: new entry to be added 56 * @head: list head to add it before 57 * 58 * Insert a new entry before the specified head. 59 * This is useful for implementing queues. 60 */ 61static inline void list_add_tail(struct list_head *new, struct list_head *head) 62{ 63 __list_add(new, head->prev, head); 64} 65 66/* 67 * Delete a list entry by making the prev/next entries 68 * point to each other. 69 * 70 * This is only for internal list manipulation where we know 71 * the prev/next entries already! 72 */ 73static inline void __list_del(struct list_head * prev, struct list_head * next) 74{ 75 next->prev = prev; 76 prev->next = next; 77} 78 79/** 80 * list_del - deletes entry from list. 81 * @entry: the element to delete from the list. 82 * Note: list_empty() on entry does not return true after this, the entry is 83 * in an undefined state. 84 */ 85#ifndef CONFIG_DEBUG_LIST 86static inline void list_del(struct list_head *entry) 87{ 88 __list_del(entry->prev, entry->next); 89 entry->next = LIST_POISON1; 90 entry->prev = LIST_POISON2; 91} 92#else 93extern void list_del(struct list_head *entry); 94#endif 95 96/** 97 * list_replace - replace old entry by new one 98 * @old : the element to be replaced 99 * @new : the new element to insert 100 * 101 * If @old was empty, it will be overwritten. 102 */ 103static inline void list_replace(struct list_head *old, 104 struct list_head *new) 105{ 106 new->next = old->next; 107 new->next->prev = new; 108 new->prev = old->prev; 109 new->prev->next = new; 110} 111 112static inline void list_replace_init(struct list_head *old, 113 struct list_head *new) 114{ 115 list_replace(old, new); 116 INIT_LIST_HEAD(old); 117} 118 119/** 120 * list_del_init - deletes entry from list and reinitialize it. 121 * @entry: the element to delete from the list. 122 */ 123static inline void list_del_init(struct list_head *entry) 124{ 125 __list_del(entry->prev, entry->next); 126 INIT_LIST_HEAD(entry); 127} 128 129/** 130 * list_move - delete from one list and add as another's head 131 * @list: the entry to move 132 * @head: the head that will precede our entry 133 */ 134static inline void list_move(struct list_head *list, struct list_head *head) 135{ 136 __list_del(list->prev, list->next); 137 list_add(list, head); 138} 139 140/** 141 * list_move_tail - delete from one list and add as another's tail 142 * @list: the entry to move 143 * @head: the head that will follow our entry 144 */ 145static inline void list_move_tail(struct list_head *list, 146 struct list_head *head) 147{ 148 __list_del(list->prev, list->next); 149 list_add_tail(list, head); 150} 151 152/** 153 * list_is_last - tests whether @list is the last entry in list @head 154 * @list: the entry to test 155 * @head: the head of the list 156 */ 157static inline int list_is_last(const struct list_head *list, 158 const struct list_head *head) 159{ 160 return list->next == head; 161} 162 163/** 164 * list_empty - tests whether a list is empty 165 * @head: the list to test. 166 */ 167static inline int list_empty(const struct list_head *head) 168{ 169 return head->next == head; 170} 171 172/** 173 * list_empty_careful - tests whether a list is empty and not being modified 174 * @head: the list to test 175 * 176 * Description: 177 * tests whether a list is empty _and_ checks that no other CPU might be 178 * in the process of modifying either member (next or prev) 179 * 180 * NOTE: using list_empty_careful() without synchronization 181 * can only be safe if the only activity that can happen 182 * to the list entry is list_del_init(). Eg. it cannot be used 183 * if another CPU could re-list_add() it. 184 */ 185static inline int list_empty_careful(const struct list_head *head) 186{ 187 struct list_head *next = head->next; 188 return (next == head) && (next == head->prev); 189} 190 191/** 192 * list_rotate_left - rotate the list to the left 193 * @head: the head of the list 194 */ 195static inline void list_rotate_left(struct list_head *head) 196{ 197 struct list_head *first; 198 199 if (!list_empty(head)) { 200 first = head->next; 201 list_move_tail(first, head); 202 } 203} 204 205/** 206 * list_is_singular - tests whether a list has just one entry. 207 * @head: the list to test. 208 */ 209static inline int list_is_singular(const struct list_head *head) 210{ 211 return !list_empty(head) && (head->next == head->prev); 212} 213 214static inline void __list_cut_position(struct list_head *list, 215 struct list_head *head, struct list_head *entry) 216{ 217 struct list_head *new_first = entry->next; 218 list->next = head->next; 219 list->next->prev = list; 220 list->prev = entry; 221 entry->next = list; 222 head->next = new_first; 223 new_first->prev = head; 224} 225 226/** 227 * list_cut_position - cut a list into two 228 * @list: a new list to add all removed entries 229 * @head: a list with entries 230 * @entry: an entry within head, could be the head itself 231 * and if so we won't cut the list 232 * 233 * This helper moves the initial part of @head, up to and 234 * including @entry, from @head to @list. You should 235 * pass on @entry an element you know is on @head. @list 236 * should be an empty list or a list you do not care about 237 * losing its data. 238 * 239 */ 240static inline void list_cut_position(struct list_head *list, 241 struct list_head *head, struct list_head *entry) 242{ 243 if (list_empty(head)) 244 return; 245 if (list_is_singular(head) && 246 (head->next != entry && head != entry)) 247 return; 248 if (entry == head) 249 INIT_LIST_HEAD(list); 250 else 251 __list_cut_position(list, head, entry); 252} 253 254static inline void __list_splice(const struct list_head *list, 255 struct list_head *prev, 256 struct list_head *next) 257{ 258 struct list_head *first = list->next; 259 struct list_head *last = list->prev; 260 261 first->prev = prev; 262 prev->next = first; 263 264 last->next = next; 265 next->prev = last; 266} 267 268/** 269 * list_splice - join two lists, this is designed for stacks 270 * @list: the new list to add. 271 * @head: the place to add it in the first list. 272 */ 273static inline void list_splice(const struct list_head *list, 274 struct list_head *head) 275{ 276 if (!list_empty(list)) 277 __list_splice(list, head, head->next); 278} 279 280/** 281 * list_splice_tail - join two lists, each list being a queue 282 * @list: the new list to add. 283 * @head: the place to add it in the first list. 284 */ 285static inline void list_splice_tail(struct list_head *list, 286 struct list_head *head) 287{ 288 if (!list_empty(list)) 289 __list_splice(list, head->prev, head); 290} 291 292/** 293 * list_splice_init - join two lists and reinitialise the emptied list. 294 * @list: the new list to add. 295 * @head: the place to add it in the first list. 296 * 297 * The list at @list is reinitialised 298 */ 299static inline void list_splice_init(struct list_head *list, 300 struct list_head *head) 301{ 302 if (!list_empty(list)) { 303 __list_splice(list, head, head->next); 304 INIT_LIST_HEAD(list); 305 } 306} 307 308/** 309 * list_splice_tail_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 * Each of the lists is a queue. 314 * The list at @list is reinitialised 315 */ 316static inline void list_splice_tail_init(struct list_head *list, 317 struct list_head *head) 318{ 319 if (!list_empty(list)) { 320 __list_splice(list, head->prev, head); 321 INIT_LIST_HEAD(list); 322 } 323} 324 325/** 326 * list_entry - get the struct for this entry 327 * @ptr: the &struct list_head pointer. 328 * @type: the type of the struct this is embedded in. 329 * @member: the name of the list_struct within the struct. 330 */ 331#define list_entry(ptr, type, member) \ 332 container_of(ptr, type, member) 333 334/** 335 * list_first_entry - get the first element from a list 336 * @ptr: the list head to take the element from. 337 * @type: the type of the struct this is embedded in. 338 * @member: the name of the list_struct within the struct. 339 * 340 * Note, that list is expected to be not empty. 341 */ 342#define list_first_entry(ptr, type, member) \ 343 list_entry((ptr)->next, type, member) 344 345/** 346 * list_for_each - iterate over a list 347 * @pos: the &struct list_head to use as a loop cursor. 348 * @head: the head for your list. 349 */ 350#define list_for_each(pos, head) \ 351 for (pos = (head)->next; prefetch(pos->next), pos != (head); \ 352 pos = pos->next) 353 354/** 355 * __list_for_each - iterate over a list 356 * @pos: the &struct list_head to use as a loop cursor. 357 * @head: the head for your list. 358 * 359 * This variant differs from list_for_each() in that it's the 360 * simplest possible list iteration code, no prefetching is done. 361 * Use this for code that knows the list to be very short (empty 362 * or 1 entry) most of the time. 363 */ 364#define __list_for_each(pos, head) \ 365 for (pos = (head)->next; pos != (head); pos = pos->next) 366 367/** 368 * list_for_each_prev - iterate over a list backwards 369 * @pos: the &struct list_head to use as a loop cursor. 370 * @head: the head for your list. 371 */ 372#define list_for_each_prev(pos, head) \ 373 for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ 374 pos = pos->prev) 375 376/** 377 * list_for_each_safe - iterate over a list safe against removal of list entry 378 * @pos: the &struct list_head to use as a loop cursor. 379 * @n: another &struct list_head to use as temporary storage 380 * @head: the head for your list. 381 */ 382#define list_for_each_safe(pos, n, head) \ 383 for (pos = (head)->next, n = pos->next; pos != (head); \ 384 pos = n, n = pos->next) 385 386/** 387 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry 388 * @pos: the &struct list_head to use as a loop cursor. 389 * @n: another &struct list_head to use as temporary storage 390 * @head: the head for your list. 391 */ 392#define list_for_each_prev_safe(pos, n, head) \ 393 for (pos = (head)->prev, n = pos->prev; \ 394 prefetch(pos->prev), pos != (head); \ 395 pos = n, n = pos->prev) 396 397/** 398 * list_for_each_entry - iterate over list of given type 399 * @pos: the type * to use as a loop cursor. 400 * @head: the head for your list. 401 * @member: the name of the list_struct within the struct. 402 */ 403#define list_for_each_entry(pos, head, member) \ 404 for (pos = list_entry((head)->next, typeof(*pos), member); \ 405 prefetch(pos->member.next), &pos->member != (head); \ 406 pos = list_entry(pos->member.next, typeof(*pos), member)) 407 408/** 409 * list_for_each_entry_reverse - iterate backwards over list of given type. 410 * @pos: the type * to use as a loop cursor. 411 * @head: the head for your list. 412 * @member: the name of the list_struct within the struct. 413 */ 414#define list_for_each_entry_reverse(pos, head, member) \ 415 for (pos = list_entry((head)->prev, typeof(*pos), member); \ 416 prefetch(pos->member.prev), &pos->member != (head); \ 417 pos = list_entry(pos->member.prev, typeof(*pos), member)) 418 419/** 420 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() 421 * @pos: the type * to use as a start point 422 * @head: the head of the list 423 * @member: the name of the list_struct within the struct. 424 * 425 * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). 426 */ 427#define list_prepare_entry(pos, head, member) \ 428 ((pos) ? : list_entry(head, typeof(*pos), member)) 429 430/** 431 * list_for_each_entry_continue - continue iteration over list of given type 432 * @pos: the type * to use as a loop cursor. 433 * @head: the head for your list. 434 * @member: the name of the list_struct within the struct. 435 * 436 * Continue to iterate over list of given type, continuing after 437 * the current position. 438 */ 439#define list_for_each_entry_continue(pos, head, member) \ 440 for (pos = list_entry(pos->member.next, typeof(*pos), member); \ 441 prefetch(pos->member.next), &pos->member != (head); \ 442 pos = list_entry(pos->member.next, typeof(*pos), member)) 443 444/** 445 * list_for_each_entry_continue_reverse - iterate backwards from the given point 446 * @pos: the type * to use as a loop cursor. 447 * @head: the head for your list. 448 * @member: the name of the list_struct within the struct. 449 * 450 * Start to iterate over list of given type backwards, continuing after 451 * the current position. 452 */ 453#define list_for_each_entry_continue_reverse(pos, head, member) \ 454 for (pos = list_entry(pos->member.prev, typeof(*pos), member); \ 455 prefetch(pos->member.prev), &pos->member != (head); \ 456 pos = list_entry(pos->member.prev, typeof(*pos), member)) 457 458/** 459 * list_for_each_entry_from - iterate over list of given type from the current point 460 * @pos: the type * to use as a loop cursor. 461 * @head: the head for your list. 462 * @member: the name of the list_struct within the struct. 463 * 464 * Iterate over list of given type, continuing from current position. 465 */ 466#define list_for_each_entry_from(pos, head, member) \ 467 for (; prefetch(pos->member.next), &pos->member != (head); \ 468 pos = list_entry(pos->member.next, typeof(*pos), member)) 469 470/** 471 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry 472 * @pos: the type * to use as a loop cursor. 473 * @n: another type * to use as temporary storage 474 * @head: the head for your list. 475 * @member: the name of the list_struct within the struct. 476 */ 477#define list_for_each_entry_safe(pos, n, head, member) \ 478 for (pos = list_entry((head)->next, typeof(*pos), member), \ 479 n = list_entry(pos->member.next, typeof(*pos), member); \ 480 &pos->member != (head); \ 481 pos = n, n = list_entry(n->member.next, typeof(*n), member)) 482 483/** 484 * list_for_each_entry_safe_continue - continue list iteration safe against removal 485 * @pos: the type * to use as a loop cursor. 486 * @n: another type * to use as temporary storage 487 * @head: the head for your list. 488 * @member: the name of the list_struct within the struct. 489 * 490 * Iterate over list of given type, continuing after current point, 491 * safe against removal of list entry. 492 */ 493#define list_for_each_entry_safe_continue(pos, n, head, member) \ 494 for (pos = list_entry(pos->member.next, typeof(*pos), member), \ 495 n = list_entry(pos->member.next, typeof(*pos), member); \ 496 &pos->member != (head); \ 497 pos = n, n = list_entry(n->member.next, typeof(*n), member)) 498 499/** 500 * list_for_each_entry_safe_from - iterate over list from current point safe against removal 501 * @pos: the type * to use as a loop cursor. 502 * @n: another type * to use as temporary storage 503 * @head: the head for your list. 504 * @member: the name of the list_struct within the struct. 505 * 506 * Iterate over list of given type from current point, safe against 507 * removal of list entry. 508 */ 509#define list_for_each_entry_safe_from(pos, n, head, member) \ 510 for (n = list_entry(pos->member.next, typeof(*pos), member); \ 511 &pos->member != (head); \ 512 pos = n, n = list_entry(n->member.next, typeof(*n), member)) 513 514/** 515 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal 516 * @pos: the type * to use as a loop cursor. 517 * @n: another type * to use as temporary storage 518 * @head: the head for your list. 519 * @member: the name of the list_struct within the struct. 520 * 521 * Iterate backwards over list of given type, safe against removal 522 * of list entry. 523 */ 524#define list_for_each_entry_safe_reverse(pos, n, head, member) \ 525 for (pos = list_entry((head)->prev, typeof(*pos), member), \ 526 n = list_entry(pos->member.prev, typeof(*pos), member); \ 527 &pos->member != (head); \ 528 pos = n, n = list_entry(n->member.prev, typeof(*n), member)) 529 530/** 531 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop 532 * @pos: the loop cursor used in the list_for_each_entry_safe loop 533 * @n: temporary storage used in list_for_each_entry_safe 534 * @member: the name of the list_struct within the struct. 535 * 536 * list_safe_reset_next is not safe to use in general if the list may be 537 * modified concurrently (eg. the lock is dropped in the loop body). An 538 * exception to this is if the cursor element (pos) is pinned in the list, 539 * and list_safe_reset_next is called after re-taking the lock and before 540 * completing the current iteration of the loop body. 541 */ 542#define list_safe_reset_next(pos, n, member) \ 543 n = list_entry(pos->member.next, typeof(*pos), member) 544 545#define HLIST_HEAD_INIT { .first = NULL } 546#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } 547#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) 548static inline void INIT_HLIST_NODE(struct hlist_node *h) 549{ 550 h->next = NULL; 551 h->pprev = NULL; 552} 553 554static inline int hlist_unhashed(const struct hlist_node *h) 555{ 556 return !h->pprev; 557} 558 559static inline int hlist_empty(const struct hlist_head *h) 560{ 561 return !h->first; 562} 563 564static inline void __hlist_del(struct hlist_node *n) 565{ 566 struct hlist_node *next = n->next; 567 struct hlist_node **pprev = n->pprev; 568 *pprev = next; 569 if (next) 570 next->pprev = pprev; 571} 572 573static inline void hlist_del(struct hlist_node *n) 574{ 575 __hlist_del(n); 576 n->next = LIST_POISON1; 577 n->pprev = LIST_POISON2; 578} 579 580static inline void hlist_del_init(struct hlist_node *n) 581{ 582 if (!hlist_unhashed(n)) { 583 __hlist_del(n); 584 INIT_HLIST_NODE(n); 585 } 586} 587 588static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) 589{ 590 struct hlist_node *first = h->first; 591 n->next = first; 592 if (first) 593 first->pprev = &n->next; 594 h->first = n; 595 n->pprev = &h->first; 596} 597 598/* next must be != NULL */ 599static inline void hlist_add_before(struct hlist_node *n, 600 struct hlist_node *next) 601{ 602 n->pprev = next->pprev; 603 n->next = next; 604 next->pprev = &n->next; 605 *(n->pprev) = n; 606} 607 608static inline void hlist_add_after(struct hlist_node *n, 609 struct hlist_node *next) 610{ 611 next->next = n->next; 612 n->next = next; 613 next->pprev = &n->next; 614 615 if(next->next) 616 next->next->pprev = &next->next; 617} 618 619/* 620 * Move a list from one list head to another. Fixup the pprev 621 * reference of the first entry if it exists. 622 */ 623static inline void hlist_move_list(struct hlist_head *old, 624 struct hlist_head *new) 625{ 626 new->first = old->first; 627 if (new->first) 628 new->first->pprev = &new->first; 629 old->first = NULL; 630} 631 632#define hlist_entry(ptr, type, member) container_of(ptr,type,member) 633 634#define hlist_for_each(pos, head) \ 635 for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ 636 pos = pos->next) 637 638#define hlist_for_each_safe(pos, n, head) \ 639 for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ 640 pos = n) 641 642/** 643 * hlist_for_each_entry - iterate over list of given type 644 * @tpos: the type * to use as a loop cursor. 645 * @pos: the &struct hlist_node to use as a loop cursor. 646 * @head: the head for your list. 647 * @member: the name of the hlist_node within the struct. 648 */ 649#define hlist_for_each_entry(tpos, pos, head, member) \ 650 for (pos = (head)->first; \ 651 pos && ({ prefetch(pos->next); 1;}) && \ 652 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ 653 pos = pos->next) 654 655/** 656 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point 657 * @tpos: the type * to use as a loop cursor. 658 * @pos: the &struct hlist_node to use as a loop cursor. 659 * @member: the name of the hlist_node within the struct. 660 */ 661#define hlist_for_each_entry_continue(tpos, pos, member) \ 662 for (pos = (pos)->next; \ 663 pos && ({ prefetch(pos->next); 1;}) && \ 664 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ 665 pos = pos->next) 666 667/** 668 * hlist_for_each_entry_from - iterate over a hlist continuing from current point 669 * @tpos: the type * to use as a loop cursor. 670 * @pos: the &struct hlist_node to use as a loop cursor. 671 * @member: the name of the hlist_node within the struct. 672 */ 673#define hlist_for_each_entry_from(tpos, pos, member) \ 674 for (; pos && ({ prefetch(pos->next); 1;}) && \ 675 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ 676 pos = pos->next) 677 678/** 679 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry 680 * @tpos: the type * to use as a loop cursor. 681 * @pos: the &struct hlist_node to use as a loop cursor. 682 * @n: another &struct hlist_node to use as temporary storage 683 * @head: the head for your list. 684 * @member: the name of the hlist_node within the struct. 685 */ 686#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ 687 for (pos = (head)->first; \ 688 pos && ({ n = pos->next; 1; }) && \ 689 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ 690 pos = n) 691 692#endif 693