share/list.h

   1 #ifndef _LINUX_LIST_H
   2 #define _LINUX_LIST_H
   3
   4 #include "stddef.h"
   5 #include "poison.h"
   6 #include "prefetch.h"
   7 //ust// #include <asm/system.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 struct list_head {
  20         struct list_head *next, *prev;
  21 };
  22
  23 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  24
  25 #define LIST_HEAD(name) \
  26         struct list_head name = LIST_HEAD_INIT(name)
  27
  28 static inline void INIT_LIST_HEAD(struct list_head *list)
  29 {
  30         list->next = list;
  31         list->prev = list;
  32 }
  33
  34 /*
  35  * Insert a new entry between two known consecutive entries.
  36  *
  37  * This is only for internal list manipulation where we know
  38  * the prev/next entries already!
  39  */
  40 #ifndef CONFIG_DEBUG_LIST
  41 static inline void __list_add(struct list_head *new,
  42                               struct list_head *prev,
  43                               struct list_head *next)
  44 {
  45         next->prev = new;
  46         new->next = next;
  47         new->prev = prev;
  48         prev->next = new;
  49 }
  50 #else
  51 extern void __list_add(struct list_head *new,
  52                               struct list_head *prev,
  53                               struct list_head *next);
  54 #endif
  55
  56 /**
  57  * list_add - add a new entry
  58  * @new: new entry to be added
  59  * @head: list head to add it after
  60  *
  61  * Insert a new entry after the specified head.
  62  * This is good for implementing stacks.
  63  */
  64 static inline void list_add(struct list_head *new, struct list_head *head)
  65 {
  66         __list_add(new, head, head->next);
  67 }
  68
  69
  70 /**
  71  * list_add_tail - add a new entry
  72  * @new: new entry to be added
  73  * @head: list head to add it before
  74  *
  75  * Insert a new entry before the specified head.
  76  * This is useful for implementing queues.
  77  */
  78 static inline void list_add_tail(struct list_head *new, struct list_head *head)
  79 {
  80         __list_add(new, head->prev, head);
  81 }
  82
  83 /*
  84  * Delete a list entry by making the prev/next entries
  85  * point to each other.
  86  *
  87  * This is only for internal list manipulation where we know
  88  * the prev/next entries already!
  89  */
  90 static inline void __list_del(struct list_head * prev, struct list_head * next)
  91 {
  92         next->prev = prev;
  93         prev->next = next;
  94 }
  95
  96 /**
  97  * list_del - deletes entry from list.
  98  * @entry: the element to delete from the list.
  99  * Note: list_empty() on entry does not return true after this, the entry is
 100  * in an undefined state.
 101  */
 102 #ifndef CONFIG_DEBUG_LIST
 103 static inline void list_del(struct list_head *entry)
 104 {
 105         __list_del(entry->prev, entry->next);
 106         entry->next = LIST_POISON1;
 107         entry->prev = LIST_POISON2;
 108 }
 109 #else
 110 extern void list_del(struct list_head *entry);
 111 #endif
 112
 113 /**
 114  * list_replace - replace old entry by new one
 115  * @old : the element to be replaced
 116  * @new : the new element to insert
 117  *
 118  * If @old was empty, it will be overwritten.
 119  */
 120 static inline void list_replace(struct list_head *old,
 121                                 struct list_head *new)
 122 {
 123         new->next = old->next;
 124         new->next->prev = new;
 125         new->prev = old->prev;
 126         new->prev->next = new;
 127 }
 128
 129 static inline void list_replace_init(struct list_head *old,
 130                                         struct list_head *new)
 131 {
 132         list_replace(old, new);
 133         INIT_LIST_HEAD(old);
 134 }
 135
 136 /**
 137  * list_del_init - deletes entry from list and reinitialize it.
 138  * @entry: the element to delete from the list.
 139  */
 140 static inline void list_del_init(struct list_head *entry)
 141 {
 142         __list_del(entry->prev, entry->next);
 143         INIT_LIST_HEAD(entry);
 144 }
 145
 146 /**
 147  * list_move - delete from one list and add as another's head
 148  * @list: the entry to move
 149  * @head: the head that will precede our entry
 150  */
 151 static inline void list_move(struct list_head *list, struct list_head *head)
 152 {
 153         __list_del(list->prev, list->next);
 154         list_add(list, head);
 155 }
 156
 157 /**
 158  * list_move_tail - delete from one list and add as another's tail
 159  * @list: the entry to move
 160  * @head: the head that will follow our entry
 161  */
 162 static inline void list_move_tail(struct list_head *list,
 163                                   struct list_head *head)
 164 {
 165         __list_del(list->prev, list->next);
 166         list_add_tail(list, head);
 167 }
 168
 169 /**
 170  * list_is_last - tests whether @list is the last entry in list @head
 171  * @list: the entry to test
 172  * @head: the head of the list
 173  */
 174 static inline int list_is_last(const struct list_head *list,
 175                                 const struct list_head *head)
 176 {
 177         return list->next == head;
 178 }
 179
 180 /**
 181  * list_empty - tests whether a list is empty
 182  * @head: the list to test.
 183  */
 184 static inline int list_empty(const struct list_head *head)
 185 {
 186         return head->next == head;
 187 }
 188
 189 /**
 190  * list_empty_careful - tests whether a list is empty and not being modified
 191  * @head: the list to test
 192  *
 193  * Description:
 194  * tests whether a list is empty _and_ checks that no other CPU might be
 195  * in the process of modifying either member (next or prev)
 196  *
 197  * NOTE: using list_empty_careful() without synchronization
 198  * can only be safe if the only activity that can happen
 199  * to the list entry is list_del_init(). Eg. it cannot be used
 200  * if another CPU could re-list_add() it.
 201  */
 202 static inline int list_empty_careful(const struct list_head *head)
 203 {
 204         struct list_head *next = head->next;
 205         return (next == head) && (next == head->prev);
 206 }
 207
 208 /**
 209  * list_is_singular - tests whether a list has just one entry.
 210  * @head: the list to test.
 211  */
 212 static inline int list_is_singular(const struct list_head *head)
 213 {
 214         return !list_empty(head) && (head->next == head->prev);
 215 }
 216
 217 static inline void __list_cut_position(struct list_head *list,
 218                 struct list_head *head, struct list_head *entry)
 219 {
 220         struct list_head *new_first = entry->next;
 221         list->next = head->next;
 222         list->next->prev = list;
 223         list->prev = entry;
 224         entry->next = list;
 225         head->next = new_first;
 226         new_first->prev = head;
 227 }
 228
 229 /**
 230  * list_cut_position - cut a list into two
 231  * @list: a new list to add all removed entries
 232  * @head: a list with entries
 233  * @entry: an entry within head, could be the head itself
 234  *      and if so we won't cut the list
 235  *
 236  * This helper moves the initial part of @head, up to and
 237  * including @entry, from @head to @list. You should
 238  * pass on @entry an element you know is on @head. @list
 239  * should be an empty list or a list you do not care about
 240  * losing its data.
 241  *
 242  */
 243 static inline void list_cut_position(struct list_head *list,
 244                 struct list_head *head, struct list_head *entry)
 245 {
 246         if (list_empty(head))
 247                 return;
 248         if (list_is_singular(head) &&
 249                 (head->next != entry && head != entry))
 250                 return;
 251         if (entry == head)
 252                 INIT_LIST_HEAD(list);
 253         else
 254                 __list_cut_position(list, head, entry);
 255 }
 256
 257 static inline void __list_splice(const struct list_head *list,
 258                                  struct list_head *prev,
 259                                  struct list_head *next)
 260 {
 261         struct list_head *first = list->next;
 262         struct list_head *last = list->prev;
 263
 264         first->prev = prev;
 265         prev->next = first;
 266
 267         last->next = next;
 268         next->prev = last;
 269 }
 270
 271 /**
 272  * list_splice - join two lists, this is designed for stacks
 273  * @list: the new list to add.
 274  * @head: the place to add it in the first list.
 275  */
 276 static inline void list_splice(const struct list_head *list,
 277                                 struct list_head *head)
 278 {
 279         if (!list_empty(list))
 280                 __list_splice(list, head, head->next);
 281 }
 282
 283 /**
 284  * list_splice_tail - join two lists, each list being a queue
 285  * @list: the new list to add.
 286  * @head: the place to add it in the first list.
 287  */
 288 static inline void list_splice_tail(struct list_head *list,
 289                                 struct list_head *head)
 290 {
 291         if (!list_empty(list))
 292                 __list_splice(list, head->prev, head);
 293 }
 294
 295 /**
 296  * list_splice_init - join two lists and reinitialise the emptied list.
 297  * @list: the new list to add.
 298  * @head: the place to add it in the first list.
 299  *
 300  * The list at @list is reinitialised
 301  */
 302 static inline void list_splice_init(struct list_head *list,
 303                                     struct list_head *head)
 304 {
 305         if (!list_empty(list)) {
 306                 __list_splice(list, head, head->next);
 307                 INIT_LIST_HEAD(list);
 308         }
 309 }
 310
 311 /**
 312  * list_splice_tail_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  * Each of the lists is a queue.
 317  * The list at @list is reinitialised
 318  */
 319 static inline void list_splice_tail_init(struct list_head *list,
 320                                          struct list_head *head)
 321 {
 322         if (!list_empty(list)) {
 323                 __list_splice(list, head->prev, head);
 324                 INIT_LIST_HEAD(list);
 325         }
 326 }
 327
 328 /**
 329  * list_entry - get the struct for this entry
 330  * @ptr:        the &struct list_head pointer.
 331  * @type:       the type of the struct this is embedded in.
 332  * @member:     the name of the list_struct within the struct.
 333  */
 334 #define list_entry(ptr, type, member) \
 335         container_of(ptr, type, member)
 336
 337 /**
 338  * list_first_entry - get the first element from a list
 339  * @ptr:        the list head to take the element from.
 340  * @type:       the type of the struct this is embedded in.
 341  * @member:     the name of the list_struct within the struct.
 342  *
 343  * Note, that list is expected to be not empty.
 344  */
 345 #define list_first_entry(ptr, type, member) \
 346         list_entry((ptr)->next, type, member)
 347
 348 /**
 349  * list_for_each        -       iterate over a list
 350  * @pos:        the &struct list_head to use as a loop cursor.
 351  * @head:       the head for your list.
 352  */
 353 #define list_for_each(pos, head) \
 354         for (pos = (head)->next; prefetch(pos->next), pos != (head); \
 355                 pos = pos->next)
 356
 357 /**
 358  * __list_for_each      -       iterate over a list
 359  * @pos:        the &struct list_head to use as a loop cursor.
 360  * @head:       the head for your list.
 361  *
 362  * This variant differs from list_for_each() in that it's the
 363  * simplest possible list iteration code, no prefetching is done.
 364  * Use this for code that knows the list to be very short (empty
 365  * or 1 entry) most of the time.
 366  */
 367 #define __list_for_each(pos, head) \
 368         for (pos = (head)->next; pos != (head); pos = pos->next)
 369
 370 /**
 371  * list_for_each_prev   -       iterate over a list backwards
 372  * @pos:        the &struct list_head to use as a loop cursor.
 373  * @head:       the head for your list.
 374  */
 375 #define list_for_each_prev(pos, head) \
 376         for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
 377                 pos = pos->prev)
 378
 379 /**
 380  * list_for_each_safe - iterate over a list safe against removal of list entry
 381  * @pos:        the &struct list_head to use as a loop cursor.
 382  * @n:          another &struct list_head to use as temporary storage
 383  * @head:       the head for your list.
 384  */
 385 #define list_for_each_safe(pos, n, head) \
 386         for (pos = (head)->next, n = pos->next; pos != (head); \
 387                 pos = n, n = pos->next)
 388
 389 /**
 390  * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
 391  * @pos:        the &struct list_head to use as a loop cursor.
 392  * @n:          another &struct list_head to use as temporary storage
 393  * @head:       the head for your list.
 394  */
 395 #define list_for_each_prev_safe(pos, n, head) \
 396         for (pos = (head)->prev, n = pos->prev; \
 397              prefetch(pos->prev), pos != (head); \
 398              pos = n, n = pos->prev)
 399
 400 /**
 401  * list_for_each_entry  -       iterate over list of given type
 402  * @pos:        the type * to use as a loop cursor.
 403  * @head:       the head for your list.
 404  * @member:     the name of the list_struct within the struct.
 405  */
 406 #define list_for_each_entry(pos, head, member)                          \
 407         for (pos = list_entry((head)->next, typeof(*pos), member);      \
 408              prefetch(pos->member.next), &pos->member != (head);        \
 409              pos = list_entry(pos->member.next, typeof(*pos), member))
 410
 411 /**
 412  * list_for_each_entry_reverse - iterate backwards over list of given type.
 413  * @pos:        the type * to use as a loop cursor.
 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_reverse(pos, head, member)                  \
 418         for (pos = list_entry((head)->prev, typeof(*pos), member);      \
 419              prefetch(pos->member.prev), &pos->member != (head);        \
 420              pos = list_entry(pos->member.prev, typeof(*pos), member))
 421
 422 /**
 423  * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
 424  * @pos:        the type * to use as a start point
 425  * @head:       the head of the list
 426  * @member:     the name of the list_struct within the struct.
 427  *
 428  * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
 429  */
 430 #define list_prepare_entry(pos, head, member) \
 431         ((pos) ? : list_entry(head, typeof(*pos), member))
 432
 433 /**
 434  * list_for_each_entry_continue - continue iteration over list of given type
 435  * @pos:        the type * to use as a loop cursor.
 436  * @head:       the head for your list.
 437  * @member:     the name of the list_struct within the struct.
 438  *
 439  * Continue to iterate over list of given type, continuing after
 440  * the current position.
 441  */
 442 #define list_for_each_entry_continue(pos, head, member)                 \
 443         for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
 444              prefetch(pos->member.next), &pos->member != (head);        \
 445              pos = list_entry(pos->member.next, typeof(*pos), member))
 446
 447 /**
 448  * list_for_each_entry_continue_reverse - iterate backwards from the given point
 449  * @pos:        the type * to use as a loop cursor.
 450  * @head:       the head for your list.
 451  * @member:     the name of the list_struct within the struct.
 452  *
 453  * Start to iterate over list of given type backwards, continuing after
 454  * the current position.
 455  */
 456 #define list_for_each_entry_continue_reverse(pos, head, member)         \
 457         for (pos = list_entry(pos->member.prev, typeof(*pos), member);  \
 458              prefetch(pos->member.prev), &pos->member != (head);        \
 459              pos = list_entry(pos->member.prev, typeof(*pos), member))
 460
 461 /**
 462  * list_for_each_entry_from - iterate over list of given type from the current point
 463  * @pos:        the type * to use as a loop cursor.
 464  * @head:       the head for your list.
 465  * @member:     the name of the list_struct within the struct.
 466  *
 467  * Iterate over list of given type, continuing from current position.
 468  */
 469 #define list_for_each_entry_from(pos, head, member)                     \
 470         for (; prefetch(pos->member.next), &pos->member != (head);      \
 471              pos = list_entry(pos->member.next, typeof(*pos), member))
 472
 473 /**
 474  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 475  * @pos:        the type * to use as a loop cursor.
 476  * @n:          another type * to use as temporary storage
 477  * @head:       the head for your list.
 478  * @member:     the name of the list_struct within the struct.
 479  */
 480 #define list_for_each_entry_safe(pos, n, head, member)                  \
 481         for (pos = list_entry((head)->next, typeof(*pos), member),      \
 482                 n = list_entry(pos->member.next, typeof(*pos), member); \
 483              &pos->member != (head);                                    \
 484              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 485
 486 /**
 487  * list_for_each_entry_safe_continue
 488  * @pos:        the type * to use as a loop cursor.
 489  * @n:          another type * to use as temporary storage
 490  * @head:       the head for your list.
 491  * @member:     the name of the list_struct within the struct.
 492  *
 493  * Iterate over list of given type, continuing after current point,
 494  * safe against removal of list entry.
 495  */
 496 #define list_for_each_entry_safe_continue(pos, n, head, member)                 \
 497         for (pos = list_entry(pos->member.next, typeof(*pos), member),          \
 498                 n = list_entry(pos->member.next, typeof(*pos), member);         \
 499              &pos->member != (head);                                            \
 500              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 501
 502 /**
 503  * list_for_each_entry_safe_from
 504  * @pos:        the type * to use as a loop cursor.
 505  * @n:          another type * to use as temporary storage
 506  * @head:       the head for your list.
 507  * @member:     the name of the list_struct within the struct.
 508  *
 509  * Iterate over list of given type from current point, safe against
 510  * removal of list entry.
 511  */
 512 #define list_for_each_entry_safe_from(pos, n, head, member)                     \
 513         for (n = list_entry(pos->member.next, typeof(*pos), member);            \
 514              &pos->member != (head);                                            \
 515              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 516
 517 /**
 518  * list_for_each_entry_safe_reverse
 519  * @pos:        the type * to use as a loop cursor.
 520  * @n:          another type * to use as temporary storage
 521  * @head:       the head for your list.
 522  * @member:     the name of the list_struct within the struct.
 523  *
 524  * Iterate backwards over list of given type, safe against removal
 525  * of list entry.
 526  */
 527 #define list_for_each_entry_safe_reverse(pos, n, head, member)          \
 528         for (pos = list_entry((head)->prev, typeof(*pos), member),      \
 529                 n = list_entry(pos->member.prev, typeof(*pos), member); \
 530              &pos->member != (head);                                    \
 531              pos = n, n = list_entry(n->member.prev, typeof(*n), member))
 532
 533 /*
 534  * Double linked lists with a single pointer list head.
 535  * Mostly useful for hash tables where the two pointer list head is
 536  * too wasteful.
 537  * You lose the ability to access the tail in O(1).
 538  */
 539
 540 struct hlist_head {
 541         struct hlist_node *first;
 542 };
 543
 544 struct hlist_node {
 545         struct hlist_node *next, **pprev;
 546 };
 547
 548 #define HLIST_HEAD_INIT { .first = NULL }
 549 #define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
 550 #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
 551 static inline void INIT_HLIST_NODE(struct hlist_node *h)
 552 {
 553         h->next = NULL;
 554         h->pprev = NULL;
 555 }
 556
 557 static inline int hlist_unhashed(const struct hlist_node *h)
 558 {
 559         return !h->pprev;
 560 }
 561
 562 static inline int hlist_empty(const struct hlist_head *h)
 563 {
 564         return !h->first;
 565 }
 566
 567 static inline void __hlist_del(struct hlist_node *n)
 568 {
 569         struct hlist_node *next = n->next;
 570         struct hlist_node **pprev = n->pprev;
 571         *pprev = next;
 572         if (next)
 573                 next->pprev = pprev;
 574 }
 575
 576 static inline void hlist_del(struct hlist_node *n)
 577 {
 578         __hlist_del(n);
 579         n->next = LIST_POISON1;
 580         n->pprev = LIST_POISON2;
 581 }
 582
 583 static inline void hlist_del_init(struct hlist_node *n)
 584 {
 585         if (!hlist_unhashed(n)) {
 586                 __hlist_del(n);
 587                 INIT_HLIST_NODE(n);
 588         }
 589 }
 590
 591 static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
 592 {
 593         struct hlist_node *first = h->first;
 594         n->next = first;
 595         if (first)
 596                 first->pprev = &n->next;
 597         h->first = n;
 598         n->pprev = &h->first;
 599 }
 600
 601 /* next must be != NULL */
 602 static inline void hlist_add_before(struct hlist_node *n,
 603                                         struct hlist_node *next)
 604 {
 605         n->pprev = next->pprev;
 606         n->next = next;
 607         next->pprev = &n->next;
 608         *(n->pprev) = n;
 609 }
 610
 611 static inline void hlist_add_after(struct hlist_node *n,
 612                                         struct hlist_node *next)
 613 {
 614         next->next = n->next;
 615         n->next = next;
 616         next->pprev = &n->next;
 617
 618         if(next->next)
 619                 next->next->pprev  = &next->next;
 620 }
 621
 622 /*
 623  * Move a list from one list head to another. Fixup the pprev
 624  * reference of the first entry if it exists.
 625  */
 626 static inline void hlist_move_list(struct hlist_head *old,
 627                                    struct hlist_head *new)
 628 {
 629         new->first = old->first;
 630         if (new->first)
 631                 new->first->pprev = &new->first;
 632         old->first = NULL;
 633 }
 634
 635 #define hlist_entry(ptr, type, member) container_of(ptr,type,member)
 636
 637 #define hlist_for_each(pos, head) \
 638         for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
 639              pos = pos->next)
 640
 641 #define hlist_for_each_safe(pos, n, head) \
 642         for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
 643              pos = n)
 644
 645 /**
 646  * hlist_for_each_entry - iterate over list of given type
 647  * @tpos:       the type * to use as a loop cursor.
 648  * @pos:        the &struct hlist_node to use as a loop cursor.
 649  * @head:       the head for your list.
 650  * @member:     the name of the hlist_node within the struct.
 651  */
 652 #define hlist_for_each_entry(tpos, pos, head, member)                    \
 653         for (pos = (head)->first;                                        \
 654              pos && ({ prefetch(pos->next); 1;}) &&                      \
 655                 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
 656              pos = pos->next)
 657
 658 /**
 659  * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
 660  * @tpos:       the type * to use as a loop cursor.
 661  * @pos:        the &struct hlist_node to use as a loop cursor.
 662  * @member:     the name of the hlist_node within the struct.
 663  */
 664 #define hlist_for_each_entry_continue(tpos, pos, member)                 \
 665         for (pos = (pos)->next;                                          \
 666              pos && ({ prefetch(pos->next); 1;}) &&                      \
 667                 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
 668              pos = pos->next)
 669
 670 /**
 671  * hlist_for_each_entry_from - iterate over a hlist continuing from current point
 672  * @tpos:       the type * to use as a loop cursor.
 673  * @pos:        the &struct hlist_node to use as a loop cursor.
 674  * @member:     the name of the hlist_node within the struct.
 675  */
 676 #define hlist_for_each_entry_from(tpos, pos, member)                     \
 677         for (; 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_safe - iterate over list of given type safe against removal of list entry
 683  * @tpos:       the type * to use as a loop cursor.
 684  * @pos:        the &struct hlist_node to use as a loop cursor.
 685  * @n:          another &struct hlist_node to use as temporary storage
 686  * @head:       the head for your list.
 687  * @member:     the name of the hlist_node within the struct.
 688  */
 689 #define hlist_for_each_entry_safe(tpos, pos, n, head, member)            \
 690         for (pos = (head)->first;                                        \
 691              pos && ({ n = pos->next; 1; }) &&                           \
 692                 ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
 693              pos = n)
 694
 695 #endif