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1: #ifndef _LINUX_LIST_H 2: #define _LINUX_LIST_H 3: 4: #include <linux/types.h> 5: #include <linux/stddef.h> 6: #include <linux/poison.h> 7: #include <linux/const.h> 8: 9: /* 10: * Simple doubly linked list implementation. 11: * 12: * Some of the internal functions ("__xxx") are useful when 13: * manipulating whole lists rather than single entries, as 14: * sometimes we already know the next/prev entries and we can 15: * generate better code by using them directly rather than 16: * using the generic single-entry routines. 17: */ 18: 19: #define LIST_HEAD_INIT(name) { &(name), &(name) } 20: 21: #define LIST_HEAD(name) \ 22: struct list_head name = LIST_HEAD_INIT(name) 23: 24: static inline void INIT_LIST_HEAD(struct list_head *list) 25: { 26: list->next = list; 27: list->prev = list; 28: } 29: 30: /* 31: * Insert a new entry between two known consecutive entries. 32: * 33: * This is only for internal list manipulation where we know 34: * the prev/next entries already! 35: */ 36: #ifndef CONFIG_DEBUG_LIST 37: static 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: #else 47: extern void __list_add(struct list_head *new, 48: struct list_head *prev, 49: struct list_head *next); 50: #endif 51: 52: /** 53: * list_add - add a new entry 54: * @new: new entry to be added 55: * @head: list head to add it after 56: * 57: * Insert a new entry after the specified head. 58: * This is good for implementing stacks. 59: */ 60: static inline void list_add(struct list_head *new, struct list_head *head) 61: { 62: __list_add(new, head, head->next); 63: } 64: 65: 66: /** 67: * list_add_tail - add a new entry 68: * @new: new entry to be added 69: * @head: list head to add it before 70: * 71: * Insert a new entry before the specified head. 72: * This is useful for implementing queues. 73: */ 74: static inline void list_add_tail(struct list_head *new, struct list_head *head) 75: { 76: __list_add(new, head->prev, head); 77: } 78: 79: /* 80: * Delete a list entry by making the prev/next entries 81: * point to each other. 82: * 83: * This is only for internal list manipulation where we know 84: * the prev/next entries already! 85: */ 86: static inline void __list_del(struct list_head * prev, struct list_head * next) 87: { 88: next->prev = prev; 89: prev->next = next; 90: } 91: 92: /** 93: * list_del - deletes entry from list. 94: * @entry: the element to delete from the list. 95: * Note: list_empty() on entry does not return true after this, the entry is 96: * in an undefined state. 97: */ 98: #ifndef CONFIG_DEBUG_LIST 99: static inline void __list_del_entry(struct list_head *entry) 100: { 101: __list_del(entry->prev, entry->next); 102: } 103: 104: static inline void list_del(struct list_head *entry) 105: { 106: __list_del(entry->prev, entry->next); 107: entry->next = LIST_POISON1; 108: entry->prev = LIST_POISON2; 109: } 110: #else 111: extern void __list_del_entry(struct list_head *entry); 112: extern void list_del(struct list_head *entry); 113: #endif 114: 115: /** 116: * list_replace - replace old entry by new one 117: * @old : the element to be replaced 118: * @new : the new element to insert 119: * 120: * If @old was empty, it will be overwritten. 121: */ 122: static inline void list_replace(struct list_head *old, 123: struct list_head *new) 124: { 125: new->next = old->next; 126: new->next->prev = new; 127: new->prev = old->prev; 128: new->prev->next = new; 129: } 130: 131: static inline void list_replace_init(struct list_head *old, 132: struct list_head *new) 133: { 134: list_replace(old, new); 135: INIT_LIST_HEAD(old); 136: } 137: 138: /** 139: * list_del_init - deletes entry from list and reinitialize it. 140: * @entry: the element to delete from the list. 141: */ 142: static inline void list_del_init(struct list_head *entry) 143: { 144: __list_del_entry(entry); 145: INIT_LIST_HEAD(entry); 146: } 147: 148: /** 149: * list_move - delete from one list and add as another's head 150: * @list: the entry to move 151: * @head: the head that will precede our entry 152: */ 153: static inline void list_move(struct list_head *list, struct list_head *head) 154: { 155: __list_del_entry(list); 156: list_add(list, head); 157: } 158: 159: /** 160: * list_move_tail - delete from one list and add as another's tail 161: * @list: the entry to move 162: * @head: the head that will follow our entry 163: */ 164: static inline void list_move_tail(struct list_head *list, 165: struct list_head *head) 166: { 167: __list_del_entry(list); 168: list_add_tail(list, head); 169: } 170: 171: /** 172: * list_is_last - tests whether @list is the last entry in list @head 173: * @list: the entry to test 174: * @head: the head of the list 175: */ 176: static inline int list_is_last(const struct list_head *list, 177: const struct list_head *head) 178: { 179: return list->next == head; 180: } 181: 182: /** 183: * list_empty - tests whether a list is empty 184: * @head: the list to test. 185: */ 186: static inline int list_empty(const struct list_head *head) 187: { 188: return head->next == head; 189: } 190: 191: /** 192: * list_empty_careful - tests whether a list is empty and not being modified 193: * @head: the list to test 194: * 195: * Description: 196: * tests whether a list is empty _and_ checks that no other CPU might be 197: * in the process of modifying either member (next or prev) 198: * 199: * NOTE: using list_empty_careful() without synchronization 200: * can only be safe if the only activity that can happen 201: * to the list entry is list_del_init(). Eg. it cannot be used 202: * if another CPU could re-list_add() it. 203: */ 204: static inline int list_empty_careful(const struct list_head *head) 205: { 206: struct list_head *next = head->next; 207: return (next == head) && (next == head->prev); 208: } 209: 210: /** 211: * list_rotate_left - rotate the list to the left 212: * @head: the head of the list 213: */ 214: static inline void list_rotate_left(struct list_head *head) 215: { 216: struct list_head *first; 217: 218: if (!list_empty(head)) { 219: first = head->next; 220: list_move_tail(first, head); 221: } 222: } 223: 224: /** 225: * list_is_singular - tests whether a list has just one entry. 226: * @head: the list to test. 227: */ 228: static inline int list_is_singular(const struct list_head *head) 229: { 230: return !list_empty(head) && (head->next == head->prev); 231: } 232: 233: static inline void __list_cut_position(struct list_head *list, 234: struct list_head *head, struct list_head *entry) 235: { 236: struct list_head *new_first = entry->next; 237: list->next = head->next; 238: list->next->prev = list; 239: list->prev = entry; 240: entry->next = list; 241: head->next = new_first; 242: new_first->prev = head; 243: } 244: 245: /** 246: * list_cut_position - cut a list into two 247: * @list: a new list to add all removed entries 248: * @head: a list with entries 249: * @entry: an entry within head, could be the head itself 250: * and if so we won't cut the list 251: * 252: * This helper moves the initial part of @head, up to and 253: * including @entry, from @head to @list. You should 254: * pass on @entry an element you know is on @head. @list 255: * should be an empty list or a list you do not care about 256: * losing its data. 257: * 258: */ 259: static inline void list_cut_position(struct list_head *list, 260: struct list_head *head, struct list_head *entry) 261: { 262: if (list_empty(head)) 263: return; 264: if (list_is_singular(head) && 265: (head->next != entry && head != entry)) 266: return; 267: if (entry == head) 268: INIT_LIST_HEAD(list); 269: else 270: __list_cut_position(list, head, entry); 271: } 272: 273: static inline void __list_splice(const struct list_head *list, 274: struct list_head *prev, 275: struct list_head *next) 276: { 277: struct list_head *first = list->next; 278: struct list_head *last = list->prev; 279: 280: first->prev = prev; 281: prev->next = first; 282: 283: last->next = next; 284: next->prev = last; 285: } 286: 287: /** 288: * list_splice - join two lists, this is designed for stacks 289: * @list: the new list to add. 290: * @head: the place to add it in the first list. 291: */ 292: static inline void list_splice(const struct list_head *list, 293: struct list_head *head) 294: { 295: if (!list_empty(list)) 296: __list_splice(list, head, head->next); 297: } 298: 299: /** 300: * list_splice_tail - join two lists, each list being a queue 301: * @list: the new list to add. 302: * @head: the place to add it in the first list. 303: */ 304: static inline void list_splice_tail(struct list_head *list, 305: struct list_head *head) 306: { 307: if (!list_empty(list)) 308: __list_splice(list, head->prev, head); 309: } 310: 311: /** 312: * list_splice_init - join two lists and reinitialise the emptied list. 313: * @list: the new list to add. 314: * @head: the place to add it in the first list. 315: * 316: * The list at @list is reinitialised 317: */ 318: static inline void list_splice_init(struct list_head *list, 319: struct list_head *head) 320: { 321: if (!list_empty(list)) { 322: __list_splice(list, head, head->next); 323: INIT_LIST_HEAD(list); 324: } 325: } 326: 327: /** 328: * list_splice_tail_init - join two lists and reinitialise the emptied list 329: * @list: the new list to add. 330: * @head: the place to add it in the first list. 331: * 332: * Each of the lists is a queue. 333: * The list at @list is reinitialised 334: */ 335: static inline void list_splice_tail_init(struct list_head *list, 336: struct list_head *head) 337: { 338: if (!list_empty(list)) { 339: __list_splice(list, head->prev, head); 340: INIT_LIST_HEAD(list); 341: } 342: } 343: 344: /** 345: * list_entry - get the struct for this entry 346: * @ptr: the &struct list_head pointer. 347: * @type: the type of the struct this is embedded in. 348: * @member: the name of the list_struct within the struct. 349: */ 350: #define list_entry(ptr, type, member) \ 351: container_of(ptr, type, member) 352: 353: /** 354: * list_first_entry - get the first element from a list 355: * @ptr: the list head to take the element from. 356: * @type: the type of the struct this is embedded in. 357: * @member: the name of the list_struct within the struct. 358: * 359: * Note, that list is expected to be not empty. 360: */ 361: #define list_first_entry(ptr, type, member) \ 362: list_entry((ptr)->next, type, member) 363: 364: /** 365: * list_last_entry - get the last element from a list 366: * @ptr: the list head to take the element from. 367: * @type: the type of the struct this is embedded in. 368: * @member: the name of the list_struct within the struct. 369: * 370: * Note, that list is expected to be not empty. 371: */ 372: #define list_last_entry(ptr, type, member) \ 373: list_entry((ptr)->prev, type, member) 374: 375: /** 376: * list_first_entry_or_null - get the first element from a list 377: * @ptr: the list head to take the element from. 378: * @type: the type of the struct this is embedded in. 379: * @member: the name of the list_struct within the struct. 380: * 381: * Note that if the list is empty, it returns NULL. 382: */ 383: #define list_first_entry_or_null(ptr, type, member) \ 384: (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL) 385: 386: /** 387: * list_next_entry - get the next element in list 388: * @pos: the type * to cursor 389: * @member: the name of the list_struct within the struct. 390: */ 391: #define list_next_entry(pos, member) \ 392: list_entry((pos)->member.next, typeof(*(pos)), member) 393: 394: /** 395: * list_prev_entry - get the prev element in list 396: * @pos: the type * to cursor 397: * @member: the name of the list_struct within the struct. 398: */ 399: #define list_prev_entry(pos, member) \ 400: list_entry((pos)->member.prev, typeof(*(pos)), member) 401: 402: /** 403: * list_for_each - iterate over a list 404: * @pos: the &struct list_head to use as a loop cursor. 405: * @head: the head for your list. 406: */ 407: #define list_for_each(pos, head) \ 408: for (pos = (head)->next; pos != (head); pos = pos->next) 409: 410: /** 411: * list_for_each_prev - iterate over a list backwards 412: * @pos: the &struct list_head to use as a loop cursor. 413: * @head: the head for your list. 414: */ 415: #define list_for_each_prev(pos, head) \ 416: for (pos = (head)->prev; pos != (head); pos = pos->prev) 417: 418: /** 419: * list_for_each_safe - iterate over a list safe against removal of list entry 420: * @pos: the &struct list_head to use as a loop cursor. 421: * @n: another &struct list_head to use as temporary storage 422: * @head: the head for your list. 423: */ 424: #define list_for_each_safe(pos, n, head) \ 425: for (pos = (head)->next, n = pos->next; pos != (head); \ 426: pos = n, n = pos->next) 427: 428: /** 429: * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry 430: * @pos: the &struct list_head to use as a loop cursor. 431: * @n: another &struct list_head to use as temporary storage 432: * @head: the head for your list. 433: */ 434: #define list_for_each_prev_safe(pos, n, head) \ 435: for (pos = (head)->prev, n = pos->prev; \ 436: pos != (head); \ 437: pos = n, n = pos->prev) 438: 439: /** 440: * list_for_each_entry - iterate over list of given type 441: * @pos: the type * to use as a loop cursor. 442: * @head: the head for your list. 443: * @member: the name of the list_struct within the struct. 444: */ 445: #define list_for_each_entry(pos, head, member) \ 446: for (pos = list_first_entry(head, typeof(*pos), member); \ 447: &pos->member != (head); \ 448: pos = list_next_entry(pos, member)) 449: 450: /** 451: * list_for_each_entry_reverse - iterate backwards over list of given type. 452: * @pos: the type * to use as a loop cursor. 453: * @head: the head for your list. 454: * @member: the name of the list_struct within the struct. 455: */ 456: #define list_for_each_entry_reverse(pos, head, member) \ 457: for (pos = list_last_entry(head, typeof(*pos), member); \ 458: &pos->member != (head); \ 459: pos = list_prev_entry(pos, member)) 460: 461: /** 462: * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() 463: * @pos: the type * to use as a start point 464: * @head: the head of the list 465: * @member: the name of the list_struct within the struct. 466: * 467: * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). 468: */ 469: #define list_prepare_entry(pos, head, member) \ 470: ((pos) ? : list_entry(head, typeof(*pos), member)) 471: 472: /** 473: * list_for_each_entry_continue - continue iteration over list of given type 474: * @pos: the type * to use as a loop cursor. 475: * @head: the head for your list. 476: * @member: the name of the list_struct within the struct. 477: * 478: * Continue to iterate over list of given type, continuing after 479: * the current position. 480: */ 481: #define list_for_each_entry_continue(pos, head, member) \ 482: for (pos = list_next_entry(pos, member); \ 483: &pos->member != (head); \ 484: pos = list_next_entry(pos, member)) 485: 486: /** 487: * list_for_each_entry_continue_reverse - iterate backwards from the given point 488: * @pos: the type * to use as a loop cursor. 489: * @head: the head for your list. 490: * @member: the name of the list_struct within the struct. 491: * 492: * Start to iterate over list of given type backwards, continuing after 493: * the current position. 494: */ 495: #define list_for_each_entry_continue_reverse(pos, head, member) \ 496: for (pos = list_prev_entry(pos, member); \ 497: &pos->member != (head); \ 498: pos = list_prev_entry(pos, member)) 499: 500: /** 501: * list_for_each_entry_from - iterate over list of given type from the current point 502: * @pos: the type * to use as a loop cursor. 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, continuing from current position. 507: */ 508: #define list_for_each_entry_from(pos, head, member) \ 509: for (; &pos->member != (head); \ 510: pos = list_next_entry(pos, member)) 511: 512: /** 513: * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry 514: * @pos: the type * to use as a loop cursor. 515: * @n: another type * to use as temporary storage 516: * @head: the head for your list. 517: * @member: the name of the list_struct within the struct. 518: */ 519: #define list_for_each_entry_safe(pos, n, head, member) \ 520: for (pos = list_first_entry(head, typeof(*pos), member), \ 521: n = list_next_entry(pos, member); \ 522: &pos->member != (head); \ 523: pos = n, n = list_next_entry(n, member)) 524: 525: /** 526: * list_for_each_entry_safe_continue - continue list iteration safe against removal 527: * @pos: the type * to use as a loop cursor. 528: * @n: another type * to use as temporary storage 529: * @head: the head for your list. 530: * @member: the name of the list_struct within the struct. 531: * 532: * Iterate over list of given type, continuing after current point, 533: * safe against removal of list entry. 534: */ 535: #define list_for_each_entry_safe_continue(pos, n, head, member) \ 536: for (pos = list_next_entry(pos, member), \ 537: n = list_next_entry(pos, member); \ 538: &pos->member != (head); \ 539: pos = n, n = list_next_entry(n, member)) 540: 541: /** 542: * list_for_each_entry_safe_from - iterate over list from current point safe against removal 543: * @pos: the type * to use as a loop cursor. 544: * @n: another type * to use as temporary storage 545: * @head: the head for your list. 546: * @member: the name of the list_struct within the struct. 547: * 548: * Iterate over list of given type from current point, safe against 549: * removal of list entry. 550: */ 551: #define list_for_each_entry_safe_from(pos, n, head, member) \ 552: for (n = list_next_entry(pos, member); \ 553: &pos->member != (head); \ 554: pos = n, n = list_next_entry(n, member)) 555: 556: /** 557: * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal 558: * @pos: the type * to use as a loop cursor. 559: * @n: another type * to use as temporary storage 560: * @head: the head for your list. 561: * @member: the name of the list_struct within the struct. 562: * 563: * Iterate backwards over list of given type, safe against removal 564: * of list entry. 565: */ 566: #define list_for_each_entry_safe_reverse(pos, n, head, member) \ 567: for (pos = list_last_entry(head, typeof(*pos), member), \ 568: n = list_prev_entry(pos, member); \ 569: &pos->member != (head); \ 570: pos = n, n = list_prev_entry(n, member)) 571: 572: /** 573: * list_safe_reset_next - reset a stale list_for_each_entry_safe loop 574: * @pos: the loop cursor used in the list_for_each_entry_safe loop 575: * @n: temporary storage used in list_for_each_entry_safe 576: * @member: the name of the list_struct within the struct. 577: * 578: * list_safe_reset_next is not safe to use in general if the list may be 579: * modified concurrently (eg. the lock is dropped in the loop body). An 580: * exception to this is if the cursor element (pos) is pinned in the list, 581: * and list_safe_reset_next is called after re-taking the lock and before 582: * completing the current iteration of the loop body. 583: */ 584: #define list_safe_reset_next(pos, n, member) \ 585: n = list_next_entry(pos, member) 586: 587: /* 588: * Double linked lists with a single pointer list head. 589: * Mostly useful for hash tables where the two pointer list head is 590: * too wasteful. 591: * You lose the ability to access the tail in O(1). 592: */ 593: 594: #define HLIST_HEAD_INIT { .first = NULL } 595: #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } 596: #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) 597: static inline void INIT_HLIST_NODE(struct hlist_node *h) 598: { 599: h->next = NULL; 600: h->pprev = NULL; 601: } 602: 603: static inline int hlist_unhashed(const struct hlist_node *h) 604: { 605: return !h->pprev; 606: } 607: 608: static inline int hlist_empty(const struct hlist_head *h) 609: { 610: return !h->first; 611: } 612: 613: static inline void __hlist_del(struct hlist_node *n) 614: { 615: struct hlist_node *next = n->next; 616: struct hlist_node **pprev = n->pprev; 617: *pprev = next; 618: if (next) 619: next->pprev = pprev; 620: } 621: 622: static inline void hlist_del(struct hlist_node *n) 623: { 624: __hlist_del(n); 625: n->next = LIST_POISON1; 626: n->pprev = LIST_POISON2; 627: } 628: 629: static inline void hlist_del_init(struct hlist_node *n) 630: { 631: if (!hlist_unhashed(n)) { 632: __hlist_del(n); 633: INIT_HLIST_NODE(n); 634: } 635: } 636: 637: static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) 638: { 639: struct hlist_node *first = h->first; 640: n->next = first; 641: if (first) 642: first->pprev = &n->next; 643: h->first = n; 644: n->pprev = &h->first; 645: } 646: 647: /* next must be != NULL */ 648: static inline void hlist_add_before(struct hlist_node *n, 649: struct hlist_node *next) 650: { 651: n->pprev = next->pprev; 652: n->next = next; 653: next->pprev = &n->next; 654: *(n->pprev) = n; 655: } 656: 657: static inline void hlist_add_after(struct hlist_node *n, 658: struct hlist_node *next) 659: { 660: next->next = n->next; 661: n->next = next; 662: next->pprev = &n->next; 663: 664: if(next->next) 665: next->next->pprev = &next->next; 666: } 667: 668: /* after that we'll appear to be on some hlist and hlist_del will work */ 669: static inline void hlist_add_fake(struct hlist_node *n) 670: { 671: n->pprev = &n->next; 672: } 673: 674: /* 675: * Move a list from one list head to another. Fixup the pprev 676: * reference of the first entry if it exists. 677: */ 678: static inline void hlist_move_list(struct hlist_head *old, 679: struct hlist_head *new) 680: { 681: new->first = old->first; 682: if (new->first) 683: new->first->pprev = &new->first; 684: old->first = NULL; 685: } 686: 687: #define hlist_entry(ptr, type, member) container_of(ptr,type,member) 688: 689: #define hlist_for_each(pos, head) \ 690: for (pos = (head)->first; pos ; pos = pos->next) 691: 692: #define hlist_for_each_safe(pos, n, head) \ 693: for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ 694: pos = n) 695: 696: #define hlist_entry_safe(ptr, type, member) \ 697: ({ typeof(ptr) ____ptr = (ptr); \ 698: ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ 699: }) 700: 701: /** 702: * hlist_for_each_entry - iterate over list of given type 703: * @pos: the type * to use as a loop cursor. 704: * @head: the head for your list. 705: * @member: the name of the hlist_node within the struct. 706: */ 707: #define hlist_for_each_entry(pos, head, member) \ 708: for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ pos; \ 710: pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) 711: 712: /** 713: * hlist_for_each_entry_continue - iterate over a hlist continuing after current point 714: * @pos: the type * to use as a loop cursor. 715: * @member: the name of the hlist_node within the struct. 716: */ 717: #define hlist_for_each_entry_continue(pos, member) \ 718: for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ pos; \ 720: pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) 721: 722: /** 723: * hlist_for_each_entry_from - iterate over a hlist continuing from current point 724: * @pos: the type * to use as a loop cursor. 725: * @member: the name of the hlist_node within the struct. 726: */ 727: #define hlist_for_each_entry_from(pos, member) \ 728: for (; pos; \ 729: pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) 730: 731: /** 732: * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry 733: * @pos: the type * to use as a loop cursor. 734: * @n: another &struct hlist_node to use as temporary storage 735: * @head: the head for your list. 736: * @member: the name of the hlist_node within the struct. 737: */ 738: #define hlist_for_each_entry_safe(pos, n, head, member) \ 739: for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ pos && ({ n = pos->member.next; 1; }); \ 741: pos = hlist_entry_safe(n, typeof(*pos), member)) 742: 743: #endif 744: