sys/sys/queue.h

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  30  * $FreeBSD$
  31  */
  32
  33 #ifndef _SYS_QUEUE_H_
  34 #define _SYS_QUEUE_H_
  35
  36 #include <sys/cdefs.h>
  37
  38 /*
  39  * This file defines four types of data structures: singly-linked lists,
  40  * singly-linked tail queues, lists and tail queues.
  41  *
  42  * A singly-linked list is headed by a single forward pointer. The elements
  43  * are singly linked for minimum space and pointer manipulation overhead at
  44  * the expense of O(n) removal for arbitrary elements. New elements can be
  45  * added to the list after an existing element or at the head of the list.
  46  * Elements being removed from the head of the list should use the explicit
  47  * macro for this purpose for optimum efficiency. A singly-linked list may
  48  * only be traversed in the forward direction.  Singly-linked lists are ideal
  49  * for applications with large datasets and few or no removals or for
  50  * implementing a LIFO queue.
  51  *
  52  * A singly-linked tail queue is headed by a pair of pointers, one to the
  53  * head of the list and the other to the tail of the list. The elements are
  54  * singly linked for minimum space and pointer manipulation overhead at the
  55  * expense of O(n) removal for arbitrary elements. New elements can be added
  56  * to the list after an existing element, at the head of the list, or at the
  57  * end of the list. Elements being removed from the head of the tail queue
  58  * should use the explicit macro for this purpose for optimum efficiency.
  59  * A singly-linked tail queue may only be traversed in the forward direction.
  60  * Singly-linked tail queues are ideal for applications with large datasets
  61  * and few or no removals or for implementing a FIFO queue.
  62  *
  63  * A list is headed by a single forward pointer (or an array of forward
  64  * pointers for a hash table header). The elements are doubly linked
  65  * so that an arbitrary element can be removed without a need to
  66  * traverse the list. New elements can be added to the list before
  67  * or after an existing element or at the head of the list. A list
  68  * may be traversed in either direction.
  69  *
  70  * A tail queue is headed by a pair of pointers, one to the head of the
  71  * list and the other to the tail of the list. The elements are doubly
  72  * linked so that an arbitrary element can be removed without a need to
  73  * traverse the list. New elements can be added to the list before or
  74  * after an existing element, at the head of the list, or at the end of
  75  * the list. A tail queue may be traversed in either direction.
  76  *
  77  * For details on the use of these macros, see the queue(3) manual page.
  78  *
  79  *
  80  *                              SLIST   LIST    STAILQ  TAILQ
  81  * _HEAD                        +       +       +       +
  82  * _CLASS_HEAD                  +       +       +       +
  83  * _HEAD_INITIALIZER            +       +       +       +
  84  * _ENTRY                       +       +       +       +
  85  * _CLASS_ENTRY                 +       +       +       +
  86  * _INIT                        +       +       +       +
  87  * _EMPTY                       +       +       +       +
  88  * _FIRST                       +       +       +       +
  89  * _NEXT                        +       +       +       +
  90  * _PREV                        -       +       -       +
  91  * _LAST                        -       -       +       +
  92  * _FOREACH                     +       +       +       +
  93  * _FOREACH_FROM                +       +       +       +
  94  * _FOREACH_SAFE                +       +       +       +
  95  * _FOREACH_FROM_SAFE           +       +       +       +
  96  * _FOREACH_REVERSE             -       -       -       +
  97  * _FOREACH_REVERSE_FROM        -       -       -       +
  98  * _FOREACH_REVERSE_SAFE        -       -       -       +
  99  * _FOREACH_REVERSE_FROM_SAFE   -       -       -       +
 100  * _INSERT_HEAD                 +       +       +       +
 101  * _INSERT_BEFORE               -       +       -       +
 102  * _INSERT_AFTER                +       +       +       +
 103  * _INSERT_TAIL                 -       -       +       +
 104  * _CONCAT                      -       -       +       +
 105  * _REMOVE_AFTER                +       -       +       -
 106  * _REMOVE_HEAD                 +       -       +       -
 107  * _REMOVE                      +       +       +       +
 108  * _SWAP                        +       +       +       +
 109  *
 110  */
 111 #ifdef QUEUE_MACRO_DEBUG
 112 /* Store the last 2 places the queue element or head was altered */
 113 struct qm_trace {
 114         char * lastfile;
 115         int lastline;
 116         char * prevfile;
 117         int prevline;
 118 };
 119
 120 #define TRACEBUF        struct qm_trace trace;
 121 #define TRASHIT(x)      do {(x) = (void *)-1;} while (0)
 122 #define QMD_SAVELINK(name, link)        void **name = (void *)&(link)
 123
 124 #define QMD_TRACE_HEAD(head) do {                                       \
 125         (head)->trace.prevline = (head)->trace.lastline;                \
 126         (head)->trace.prevfile = (head)->trace.lastfile;                \
 127         (head)->trace.lastline = __LINE__;                              \
 128         (head)->trace.lastfile = __FILE__;                              \
 129 } while (0)
 130
 131 #define QMD_TRACE_ELEM(elem) do {                                       \
 132         (elem)->trace.prevline = (elem)->trace.lastline;                \
 133         (elem)->trace.prevfile = (elem)->trace.lastfile;                \
 134         (elem)->trace.lastline = __LINE__;                              \
 135         (elem)->trace.lastfile = __FILE__;                              \
 136 } while (0)
 137
 138 #else
 139 #define QMD_TRACE_ELEM(elem)
 140 #define QMD_TRACE_HEAD(head)
 141 #define QMD_SAVELINK(name, link)
 142 #define TRACEBUF
 143 #define TRASHIT(x)
 144 #endif  /* QUEUE_MACRO_DEBUG */
 145
 146 #ifdef __cplusplus
 147 /*
 148  * In C++ there can be structure lists and class lists:
 149  */
 150 #define QUEUE_TYPEOF(type) type
 151 #else
 152 #define QUEUE_TYPEOF(type) struct type
 153 #endif
 154
 155 /*
 156  * Singly-linked List declarations.
 157  */
 158 #define SLIST_HEAD(name, type)                                          \
 159 struct name {                                                           \
 160         struct type *slh_first; /* first element */                     \
 161 }
 162
 163 #define SLIST_CLASS_HEAD(name, type)                                    \
 164 struct name {                                                           \
 165         class type *slh_first;  /* first element */                     \
 166 }
 167
 168 #define SLIST_HEAD_INITIALIZER(head)                                    \
 169         { NULL }
 170
 171 #define SLIST_ENTRY(type)                                               \
 172 struct {                                                                \
 173         struct type *sle_next;  /* next element */                      \
 174 }
 175
 176 #define SLIST_CLASS_ENTRY(type)                                         \
 177 struct {                                                                \
 178         class type *sle_next;           /* next element */              \
 179 }
 180
 181 /*
 182  * Singly-linked List functions.
 183  */
 184 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 185
 186 #define SLIST_FIRST(head)       ((head)->slh_first)
 187
 188 #define SLIST_FOREACH(var, head, field)                                 \
 189         for ((var) = SLIST_FIRST((head));                               \
 190             (var);                                                      \
 191             (var) = SLIST_NEXT((var), field))
 192
 193 #define SLIST_FOREACH_FROM(var, head, field)                            \
 194         for ((var) = ((var) ? (var) : SLIST_FIRST((head)));             \
 195             (var);                                                      \
 196             (var) = SLIST_NEXT((var), field))
 197
 198 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 199         for ((var) = SLIST_FIRST((head));                               \
 200             (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 201             (var) = (tvar))
 202
 203 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar)                 \
 204         for ((var) = ((var) ? (var) : SLIST_FIRST((head)));             \
 205             (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 206             (var) = (tvar))
 207
 208 #define SLIST_FOREACH_PREVPTR(var, varp, head, field)                   \
 209         for ((varp) = &SLIST_FIRST((head));                             \
 210             ((var) = *(varp)) != NULL;                                  \
 211             (varp) = &SLIST_NEXT((var), field))
 212
 213 #define SLIST_INIT(head) do {                                           \
 214         SLIST_FIRST((head)) = NULL;                                     \
 215 } while (0)
 216
 217 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 218         SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
 219         SLIST_NEXT((slistelm), field) = (elm);                          \
 220 } while (0)
 221
 222 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 223         SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
 224         SLIST_FIRST((head)) = (elm);                                    \
 225 } while (0)
 226
 227 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 228
 229 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 230         QMD_SAVELINK(oldnext, (elm)->field.sle_next);                   \
 231         if (SLIST_FIRST((head)) == (elm)) {                             \
 232                 SLIST_REMOVE_HEAD((head), field);                       \
 233         }                                                               \
 234         else {                                                          \
 235                 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head);         \
 236                 while (SLIST_NEXT(curelm, field) != (elm))              \
 237                         curelm = SLIST_NEXT(curelm, field);             \
 238                 SLIST_REMOVE_AFTER(curelm, field);                      \
 239         }                                                               \
 240         TRASHIT(*oldnext);                                              \
 241 } while (0)
 242
 243 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 244         SLIST_NEXT(elm, field) =                                        \
 245             SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
 246 } while (0)
 247
 248 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 249         SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
 250 } while (0)
 251
 252 #define SLIST_SWAP(head1, head2, type) do {                             \
 253         QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1);            \
 254         SLIST_FIRST(head1) = SLIST_FIRST(head2);                        \
 255         SLIST_FIRST(head2) = swap_first;                                \
 256 } while (0)
 257
 258 /*
 259  * Singly-linked Tail queue declarations.
 260  */
 261 #define STAILQ_HEAD(name, type)                                         \
 262 struct name {                                                           \
 263         struct type *stqh_first;/* first element */                     \
 264         struct type **stqh_last;/* addr of last next element */         \
 265 }
 266
 267 #define STAILQ_CLASS_HEAD(name, type)                                   \
 268 struct name {                                                           \
 269         class type *stqh_first; /* first element */                     \
 270         class type **stqh_last; /* addr of last next element */         \
 271 }
 272
 273 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 274         { NULL, &(head).stqh_first }
 275
 276 #define STAILQ_ENTRY(type)                                              \
 277 struct {                                                                \
 278         struct type *stqe_next; /* next element */                      \
 279 }
 280
 281 #define STAILQ_CLASS_ENTRY(type)                                        \
 282 struct {                                                                \
 283         class type *stqe_next;  /* next element */                      \
 284 }
 285
 286 /*
 287  * Singly-linked Tail queue functions.
 288  */
 289 #define STAILQ_CONCAT(head1, head2) do {                                \
 290         if (!STAILQ_EMPTY((head2))) {                                   \
 291                 *(head1)->stqh_last = (head2)->stqh_first;              \
 292                 (head1)->stqh_last = (head2)->stqh_last;                \
 293                 STAILQ_INIT((head2));                                   \
 294         }                                                               \
 295 } while (0)
 296
 297 #define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
 298
 299 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 300
 301 #define STAILQ_FOREACH(var, head, field)                                \
 302         for((var) = STAILQ_FIRST((head));                               \
 303            (var);                                                       \
 304            (var) = STAILQ_NEXT((var), field))
 305
 306 #define STAILQ_FOREACH_FROM(var, head, field)                           \
 307         for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));            \
 308            (var);                                                       \
 309            (var) = STAILQ_NEXT((var), field))
 310
 311 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 312         for ((var) = STAILQ_FIRST((head));                              \
 313             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 314             (var) = (tvar))
 315
 316 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)                \
 317         for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));            \
 318             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 319             (var) = (tvar))
 320
 321 #define STAILQ_INIT(head) do {                                          \
 322         STAILQ_FIRST((head)) = NULL;                                    \
 323         (head)->stqh_last = &STAILQ_FIRST((head));                      \
 324 } while (0)
 325
 326 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {               \
 327         if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
 328                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 329         STAILQ_NEXT((tqelm), field) = (elm);                            \
 330 } while (0)
 331
 332 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 333         if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
 334                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 335         STAILQ_FIRST((head)) = (elm);                                   \
 336 } while (0)
 337
 338 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 339         STAILQ_NEXT((elm), field) = NULL;                               \
 340         *(head)->stqh_last = (elm);                                     \
 341         (head)->stqh_last = &STAILQ_NEXT((elm), field);                 \
 342 } while (0)
 343
 344 #define STAILQ_LAST(head, type, field)                          \
 345         (STAILQ_EMPTY((head)) ? NULL :                          \
 346             __containerof((head)->stqh_last,                    \
 347             QUEUE_TYPEOF(type), field.stqe_next))
 348
 349 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 350
 351 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 352         QMD_SAVELINK(oldnext, (elm)->field.stqe_next);                  \
 353         if (STAILQ_FIRST((head)) == (elm)) {                            \
 354                 STAILQ_REMOVE_HEAD((head), field);                      \
 355         }                                                               \
 356         else {                                                          \
 357                 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head);        \
 358                 while (STAILQ_NEXT(curelm, field) != (elm))             \
 359                         curelm = STAILQ_NEXT(curelm, field);            \
 360                 STAILQ_REMOVE_AFTER(head, curelm, field);               \
 361         }                                                               \
 362         TRASHIT(*oldnext);                                              \
 363 } while (0)
 364
 365 #define STAILQ_REMOVE_AFTER(head, elm, field) do {                      \
 366         if ((STAILQ_NEXT(elm, field) =                                  \
 367              STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)      \
 368                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 369 } while (0)
 370
 371 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 372         if ((STAILQ_FIRST((head)) =                                     \
 373              STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)         \
 374                 (head)->stqh_last = &STAILQ_FIRST((head));              \
 375 } while (0)
 376
 377 #define STAILQ_SWAP(head1, head2, type) do {                            \
 378         QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1);           \
 379         QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last;            \
 380         STAILQ_FIRST(head1) = STAILQ_FIRST(head2);                      \
 381         (head1)->stqh_last = (head2)->stqh_last;                        \
 382         STAILQ_FIRST(head2) = swap_first;                               \
 383         (head2)->stqh_last = swap_last;                                 \
 384         if (STAILQ_EMPTY(head1))                                        \
 385                 (head1)->stqh_last = &STAILQ_FIRST(head1);              \
 386         if (STAILQ_EMPTY(head2))                                        \
 387                 (head2)->stqh_last = &STAILQ_FIRST(head2);              \
 388 } while (0)
 389
 390
 391 /*
 392  * List declarations.
 393  */
 394 #define LIST_HEAD(name, type)                                           \
 395 struct name {                                                           \
 396         struct type *lh_first;  /* first element */                     \
 397 }
 398
 399 #define LIST_CLASS_HEAD(name, type)                                     \
 400 struct name {                                                           \
 401         class type *lh_first;   /* first element */                     \
 402 }
 403
 404 #define LIST_HEAD_INITIALIZER(head)                                     \
 405         { NULL }
 406
 407 #define LIST_ENTRY(type)                                                \
 408 struct {                                                                \
 409         struct type *le_next;   /* next element */                      \
 410         struct type **le_prev;  /* address of previous next element */  \
 411 }
 412
 413 #define LIST_CLASS_ENTRY(type)                                          \
 414 struct {                                                                \
 415         class type *le_next;    /* next element */                      \
 416         class type **le_prev;   /* address of previous next element */  \
 417 }
 418
 419 /*
 420  * List functions.
 421  */
 422
 423 #if (defined(_KERNEL) && defined(INVARIANTS))
 424 #define QMD_LIST_CHECK_HEAD(head, field) do {                           \
 425         if (LIST_FIRST((head)) != NULL &&                               \
 426             LIST_FIRST((head))->field.le_prev !=                        \
 427              &LIST_FIRST((head)))                                       \
 428                 panic("Bad list head %p first->prev != head", (head));  \
 429 } while (0)
 430
 431 #define QMD_LIST_CHECK_NEXT(elm, field) do {                            \
 432         if (LIST_NEXT((elm), field) != NULL &&                          \
 433             LIST_NEXT((elm), field)->field.le_prev !=                   \
 434              &((elm)->field.le_next))                                   \
 435                 panic("Bad link elm %p next->prev != elm", (elm));      \
 436 } while (0)
 437
 438 #define QMD_LIST_CHECK_PREV(elm, field) do {                            \
 439         if (*(elm)->field.le_prev != (elm))                             \
 440                 panic("Bad link elm %p prev->next != elm", (elm));      \
 441 } while (0)
 442 #else
 443 #define QMD_LIST_CHECK_HEAD(head, field)
 444 #define QMD_LIST_CHECK_NEXT(elm, field)
 445 #define QMD_LIST_CHECK_PREV(elm, field)
 446 #endif /* (_KERNEL && INVARIANTS) */
 447
 448 #define LIST_EMPTY(head)        ((head)->lh_first == NULL)
 449
 450 #define LIST_FIRST(head)        ((head)->lh_first)
 451
 452 #define LIST_FOREACH(var, head, field)                                  \
 453         for ((var) = LIST_FIRST((head));                                \
 454             (var);                                                      \
 455             (var) = LIST_NEXT((var), field))
 456
 457 #define LIST_FOREACH_FROM(var, head, field)                             \
 458         for ((var) = ((var) ? (var) : LIST_FIRST((head)));              \
 459             (var);                                                      \
 460             (var) = LIST_NEXT((var), field))
 461
 462 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 463         for ((var) = LIST_FIRST((head));                                \
 464             (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 465             (var) = (tvar))
 466
 467 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar)                  \
 468         for ((var) = ((var) ? (var) : LIST_FIRST((head)));              \
 469             (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 470             (var) = (tvar))
 471
 472 #define LIST_INIT(head) do {                                            \
 473         LIST_FIRST((head)) = NULL;                                      \
 474 } while (0)
 475
 476 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 477         QMD_LIST_CHECK_NEXT(listelm, field);                            \
 478         if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
 479                 LIST_NEXT((listelm), field)->field.le_prev =            \
 480                     &LIST_NEXT((elm), field);                           \
 481         LIST_NEXT((listelm), field) = (elm);                            \
 482         (elm)->field.le_prev = &LIST_NEXT((listelm), field);            \
 483 } while (0)
 484
 485 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 486         QMD_LIST_CHECK_PREV(listelm, field);                            \
 487         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 488         LIST_NEXT((elm), field) = (listelm);                            \
 489         *(listelm)->field.le_prev = (elm);                              \
 490         (listelm)->field.le_prev = &LIST_NEXT((elm), field);            \
 491 } while (0)
 492
 493 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 494         QMD_LIST_CHECK_HEAD((head), field);                             \
 495         if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)     \
 496                 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
 497         LIST_FIRST((head)) = (elm);                                     \
 498         (elm)->field.le_prev = &LIST_FIRST((head));                     \
 499 } while (0)
 500
 501 #define LIST_NEXT(elm, field)   ((elm)->field.le_next)
 502
 503 #define LIST_PREV(elm, head, type, field)                       \
 504         ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL :   \
 505             __containerof((elm)->field.le_prev,                 \
 506             QUEUE_TYPEOF(type), field.le_next))
 507
 508 #define LIST_REMOVE(elm, field) do {                                    \
 509         QMD_SAVELINK(oldnext, (elm)->field.le_next);                    \
 510         QMD_SAVELINK(oldprev, (elm)->field.le_prev);                    \
 511         QMD_LIST_CHECK_NEXT(elm, field);                                \
 512         QMD_LIST_CHECK_PREV(elm, field);                                \
 513         if (LIST_NEXT((elm), field) != NULL)                            \
 514                 LIST_NEXT((elm), field)->field.le_prev =                \
 515                     (elm)->field.le_prev;                               \
 516         *(elm)->field.le_prev = LIST_NEXT((elm), field);                \
 517         TRASHIT(*oldnext);                                              \
 518         TRASHIT(*oldprev);                                              \
 519 } while (0)
 520
 521 #define LIST_SWAP(head1, head2, type, field) do {                       \
 522         QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1);               \
 523         LIST_FIRST((head1)) = LIST_FIRST((head2));                      \
 524         LIST_FIRST((head2)) = swap_tmp;                                 \
 525         if ((swap_tmp = LIST_FIRST((head1))) != NULL)                   \
 526                 swap_tmp->field.le_prev = &LIST_FIRST((head1));         \
 527         if ((swap_tmp = LIST_FIRST((head2))) != NULL)                   \
 528                 swap_tmp->field.le_prev = &LIST_FIRST((head2));         \
 529 } while (0)
 530
 531 /*
 532  * Tail queue declarations.
 533  */
 534 #define TAILQ_HEAD(name, type)                                          \
 535 struct name {                                                           \
 536         struct type *tqh_first; /* first element */                     \
 537         struct type **tqh_last; /* addr of last next element */         \
 538         TRACEBUF                                                        \
 539 }
 540
 541 #define TAILQ_CLASS_HEAD(name, type)                                    \
 542 struct name {                                                           \
 543         class type *tqh_first;  /* first element */                     \
 544         class type **tqh_last;  /* addr of last next element */         \
 545         TRACEBUF                                                        \
 546 }
 547
 548 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 549         { NULL, &(head).tqh_first }
 550
 551 #define TAILQ_ENTRY(type)                                               \
 552 struct {                                                                \
 553         struct type *tqe_next;  /* next element */                      \
 554         struct type **tqe_prev; /* address of previous next element */  \
 555         TRACEBUF                                                        \
 556 }
 557
 558 #define TAILQ_CLASS_ENTRY(type)                                         \
 559 struct {                                                                \
 560         class type *tqe_next;   /* next element */                      \
 561         class type **tqe_prev;  /* address of previous next element */  \
 562         TRACEBUF                                                        \
 563 }
 564
 565 /*
 566  * Tail queue functions.
 567  */
 568 #if (defined(_KERNEL) && defined(INVARIANTS))
 569 #define QMD_TAILQ_CHECK_HEAD(head, field) do {                          \
 570         if (!TAILQ_EMPTY(head) &&                                       \
 571             TAILQ_FIRST((head))->field.tqe_prev !=                      \
 572              &TAILQ_FIRST((head)))                                      \
 573                 panic("Bad tailq head %p first->prev != head", (head)); \
 574 } while (0)
 575
 576 #define QMD_TAILQ_CHECK_TAIL(head, field) do {                          \
 577         if (*(head)->tqh_last != NULL)                                  \
 578                 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head));  \
 579 } while (0)
 580
 581 #define QMD_TAILQ_CHECK_NEXT(elm, field) do {                           \
 582         if (TAILQ_NEXT((elm), field) != NULL &&                         \
 583             TAILQ_NEXT((elm), field)->field.tqe_prev !=                 \
 584              &((elm)->field.tqe_next))                                  \
 585                 panic("Bad link elm %p next->prev != elm", (elm));      \
 586 } while (0)
 587
 588 #define QMD_TAILQ_CHECK_PREV(elm, field) do {                           \
 589         if (*(elm)->field.tqe_prev != (elm))                            \
 590                 panic("Bad link elm %p prev->next != elm", (elm));      \
 591 } while (0)
 592 #else
 593 #define QMD_TAILQ_CHECK_HEAD(head, field)
 594 #define QMD_TAILQ_CHECK_TAIL(head, headname)
 595 #define QMD_TAILQ_CHECK_NEXT(elm, field)
 596 #define QMD_TAILQ_CHECK_PREV(elm, field)
 597 #endif /* (_KERNEL && INVARIANTS) */
 598
 599 #define TAILQ_CONCAT(head1, head2, field) do {                          \
 600         if (!TAILQ_EMPTY(head2)) {                                      \
 601                 *(head1)->tqh_last = (head2)->tqh_first;                \
 602                 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 603                 (head1)->tqh_last = (head2)->tqh_last;                  \
 604                 TAILQ_INIT((head2));                                    \
 605                 QMD_TRACE_HEAD(head1);                                  \
 606                 QMD_TRACE_HEAD(head2);                                  \
 607         }                                                               \
 608 } while (0)
 609
 610 #define TAILQ_EMPTY(head)       ((head)->tqh_first == NULL)
 611
 612 #define TAILQ_FIRST(head)       ((head)->tqh_first)
 613
 614 #define TAILQ_FOREACH(var, head, field)                                 \
 615         for ((var) = TAILQ_FIRST((head));                               \
 616             (var);                                                      \
 617             (var) = TAILQ_NEXT((var), field))
 618
 619 #define TAILQ_FOREACH_FROM(var, head, field)                            \
 620         for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));             \
 621             (var);                                                      \
 622             (var) = TAILQ_NEXT((var), field))
 623
 624 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 625         for ((var) = TAILQ_FIRST((head));                               \
 626             (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 627             (var) = (tvar))
 628
 629 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)                 \
 630         for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));             \
 631             (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 632             (var) = (tvar))
 633
 634 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 635         for ((var) = TAILQ_LAST((head), headname);                      \
 636             (var);                                                      \
 637             (var) = TAILQ_PREV((var), headname, field))
 638
 639 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field)          \
 640         for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
 641             (var);                                                      \
 642             (var) = TAILQ_PREV((var), headname, field))
 643
 644 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 645         for ((var) = TAILQ_LAST((head), headname);                      \
 646             (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 647             (var) = (tvar))
 648
 649 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
 650         for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
 651             (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 652             (var) = (tvar))
 653
 654 #define TAILQ_INIT(head) do {                                           \
 655         TAILQ_FIRST((head)) = NULL;                                     \
 656         (head)->tqh_last = &TAILQ_FIRST((head));                        \
 657         QMD_TRACE_HEAD(head);                                           \
 658 } while (0)
 659
 660 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 661         QMD_TAILQ_CHECK_NEXT(listelm, field);                           \
 662         if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
 663                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 664                     &TAILQ_NEXT((elm), field);                          \
 665         else {                                                          \
 666                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 667                 QMD_TRACE_HEAD(head);                                   \
 668         }                                                               \
 669         TAILQ_NEXT((listelm), field) = (elm);                           \
 670         (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);          \
 671         QMD_TRACE_ELEM(&(elm)->field);                                  \
 672         QMD_TRACE_ELEM(&(listelm)->field);                              \
 673 } while (0)
 674
 675 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 676         QMD_TAILQ_CHECK_PREV(listelm, field);                           \
 677         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 678         TAILQ_NEXT((elm), field) = (listelm);                           \
 679         *(listelm)->field.tqe_prev = (elm);                             \
 680         (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);          \
 681         QMD_TRACE_ELEM(&(elm)->field);                                  \
 682         QMD_TRACE_ELEM(&(listelm)->field);                              \
 683 } while (0)
 684
 685 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 686         QMD_TAILQ_CHECK_HEAD(head, field);                              \
 687         if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)   \
 688                 TAILQ_FIRST((head))->field.tqe_prev =                   \
 689                     &TAILQ_NEXT((elm), field);                          \
 690         else                                                            \
 691                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 692         TAILQ_FIRST((head)) = (elm);                                    \
 693         (elm)->field.tqe_prev = &TAILQ_FIRST((head));                   \
 694         QMD_TRACE_HEAD(head);                                           \
 695         QMD_TRACE_ELEM(&(elm)->field);                                  \
 696 } while (0)
 697
 698 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 699         QMD_TAILQ_CHECK_TAIL(head, field);                              \
 700         TAILQ_NEXT((elm), field) = NULL;                                \
 701         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 702         *(head)->tqh_last = (elm);                                      \
 703         (head)->tqh_last = &TAILQ_NEXT((elm), field);                   \
 704         QMD_TRACE_HEAD(head);                                           \
 705         QMD_TRACE_ELEM(&(elm)->field);                                  \
 706 } while (0)
 707
 708 #define TAILQ_LAST(head, headname)                                      \
 709         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 710
 711 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 712
 713 #define TAILQ_PREV(elm, headname, field)                                \
 714         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 715
 716 #define TAILQ_REMOVE(head, elm, field) do {                             \
 717         QMD_SAVELINK(oldnext, (elm)->field.tqe_next);                   \
 718         QMD_SAVELINK(oldprev, (elm)->field.tqe_prev);                   \
 719         QMD_TAILQ_CHECK_NEXT(elm, field);                               \
 720         QMD_TAILQ_CHECK_PREV(elm, field);                               \
 721         if ((TAILQ_NEXT((elm), field)) != NULL)                         \
 722                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 723                     (elm)->field.tqe_prev;                              \
 724         else {                                                          \
 725                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 726                 QMD_TRACE_HEAD(head);                                   \
 727         }                                                               \
 728         *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);              \
 729         TRASHIT(*oldnext);                                              \
 730         TRASHIT(*oldprev);                                              \
 731         QMD_TRACE_ELEM(&(elm)->field);                                  \
 732 } while (0)
 733
 734 #define TAILQ_SWAP(head1, head2, type, field) do {                      \
 735         QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first;            \
 736         QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last;             \
 737         (head1)->tqh_first = (head2)->tqh_first;                        \
 738         (head1)->tqh_last = (head2)->tqh_last;                          \
 739         (head2)->tqh_first = swap_first;                                \
 740         (head2)->tqh_last = swap_last;                                  \
 741         if ((swap_first = (head1)->tqh_first) != NULL)                  \
 742                 swap_first->field.tqe_prev = &(head1)->tqh_first;       \
 743         else                                                            \
 744                 (head1)->tqh_last = &(head1)->tqh_first;                \
 745         if ((swap_first = (head2)->tqh_first) != NULL)                  \
 746                 swap_first->field.tqe_prev = &(head2)->tqh_first;       \
 747         else                                                            \
 748                 (head2)->tqh_last = &(head2)->tqh_first;                \
 749 } while (0)
 750
 751 #endif /* !_SYS_QUEUE_H_ */