kern/include/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 ROS_KERN_SYS_QUEUE_H
  34 #define ROS_KERN_SYS_QUEUE_H
  35
  36 #include <ros/common.h>    /* for __offsetof */
  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 only be traversed in the forward 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  * _HEAD_INITIALIZER            +       +       +       +
  83  * _ENTRY                       +       +       +       +
  84  * _INIT                        +       +       +       +
  85  * _EMPTY                       +       +       +       +
  86  * _FIRST                       +       +       +       +
  87  * _NEXT                        +       +       +       +
  88  * _PREV                        -       -       -       +
  89  * _LAST                        -       -       +       +
  90  * _FOREACH                     +       +       +       +
  91  * _FOREACH_SAFE                +       +       +       +
  92  * _FOREACH_REVERSE             -       -       -       +
  93  * _FOREACH_REVERSE_SAFE        -       -       -       +
  94  * _INSERT_HEAD                 +       +       +       +
  95  * _INSERT_BEFORE               -       +       -       +
  96  * _INSERT_AFTER                +       +       +       +
  97  * _INSERT_TAIL                 -       -       +       +
  98  * _CONCAT                      -       -       +       +
  99  * _REMOVE_AFTER                +       -       +       -
 100  * _REMOVE_HEAD                 +       -       +       -
 101  * _REMOVE                      +       +       +       +
 102  *
 103  */
 104 #ifdef QUEUE_MACRO_DEBUG
 105 /* ROS has TAILQ-sized elements in a vcore, exposed to userspace via the
 106  * vcoremap.  If you have QM tracing turned on, you'll mess it up. */
 107 #error "Don't use sys/queue QUEUE_MACRO_DEBUG without dealing with the vcoremap"
 108 /* Store the last 2 places the queue element or head was altered */
 109 struct qm_trace {
 110         char * lastfile;
 111         int lastline;
 112         char * prevfile;
 113         int prevline;
 114 };
 115
 116 #define TRACEBUF        struct qm_trace trace;
 117 #define TRASHIT(x)      do {(x) = (void *)-1;} while (0)
 118 #define QMD_SAVELINK(name, link)        void **name = (void *)&(link)
 119
 120 #define QMD_TRACE_HEAD(head) do {                                       \
 121         (head)->trace.prevline = (head)->trace.lastline;                \
 122         (head)->trace.prevfile = (head)->trace.lastfile;                \
 123         (head)->trace.lastline = __LINE__;                              \
 124         (head)->trace.lastfile = __FILE__;                              \
 125 } while (0)
 126
 127 #define QMD_TRACE_ELEM(elem) do {                                       \
 128         (elem)->trace.prevline = (elem)->trace.lastline;                \
 129         (elem)->trace.prevfile = (elem)->trace.lastfile;                \
 130         (elem)->trace.lastline = __LINE__;                              \
 131         (elem)->trace.lastfile = __FILE__;                              \
 132 } while (0)
 133
 134 #else
 135 #define QMD_TRACE_ELEM(elem)
 136 #define QMD_TRACE_HEAD(head)
 137 #define QMD_SAVELINK(name, link)
 138 #define TRACEBUF
 139 #define TRASHIT(x)
 140 #endif  /* QUEUE_MACRO_DEBUG */
 141
 142 /*
 143  * Singly-linked List declarations.
 144  */
 145 #define SLIST_HEAD(name, type)                                          \
 146 struct name {                                                           \
 147         struct type *slh_first; /* first element */                     \
 148 }
 149
 150 #define SLIST_HEAD_INITIALIZER(head)                                    \
 151         { NULL }
 152
 153 #define SLIST_ENTRY(type)                                               \
 154 struct {                                                                \
 155         struct type *sle_next;  /* next element */                      \
 156 }
 157
 158 /*
 159  * Singly-linked List functions.
 160  */
 161 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 162
 163 #define SLIST_FIRST(head)       ((head)->slh_first)
 164
 165 #define SLIST_FOREACH(var, head, field)                                 \
 166         for ((var) = SLIST_FIRST((head));                               \
 167             (var);                                                      \
 168             (var) = SLIST_NEXT((var), field))
 169
 170 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 171         for ((var) = SLIST_FIRST((head));                               \
 172             (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 173             (var) = (tvar))
 174
 175 #define SLIST_FOREACH_PREVPTR(var, varp, head, field)                   \
 176         for ((varp) = &SLIST_FIRST((head));                             \
 177             ((var) = *(varp)) != NULL;                                  \
 178             (varp) = &SLIST_NEXT((var), field))
 179
 180 #define SLIST_INIT(head) do {                                           \
 181         SLIST_FIRST((head)) = NULL;                                     \
 182 } while (0)
 183
 184 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 185         SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
 186         SLIST_NEXT((slistelm), field) = (elm);                          \
 187 } while (0)
 188
 189 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 190         SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
 191         SLIST_FIRST((head)) = (elm);                                    \
 192 } while (0)
 193
 194 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 195
 196 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 197         QMD_SAVELINK(oldnext, (elm)->field.sle_next);                   \
 198         if (SLIST_FIRST((head)) == (elm)) {                             \
 199                 SLIST_REMOVE_HEAD((head), field);                       \
 200         }                                                               \
 201         else {                                                          \
 202                 struct type *curelm = SLIST_FIRST((head));              \
 203                 while (SLIST_NEXT(curelm, field) != (elm))              \
 204                         curelm = SLIST_NEXT(curelm, field);             \
 205                 SLIST_REMOVE_AFTER(curelm, field);                      \
 206         }                                                               \
 207         TRASHIT(*oldnext);                                              \
 208 } while (0)
 209
 210 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 211         SLIST_NEXT(elm, field) =                                        \
 212             SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
 213 } while (0)
 214
 215 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 216         SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
 217 } while (0)
 218
 219 /*
 220  * Singly-linked Tail queue declarations.
 221  */
 222 #define STAILQ_HEAD(name, type)                                         \
 223 struct name {                                                           \
 224         struct type *stqh_first;/* first element */                     \
 225         struct type **stqh_last;/* addr of last next element */         \
 226 }
 227
 228 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 229         { NULL, &(head).stqh_first }
 230
 231 #define STAILQ_ENTRY(type)                                              \
 232 struct {                                                                \
 233         struct type *stqe_next; /* next element */                      \
 234 }
 235
 236 /*
 237  * Singly-linked Tail queue functions.
 238  */
 239 #define STAILQ_CONCAT(head1, head2) do {                                \
 240         if (!STAILQ_EMPTY((head2))) {                                   \
 241                 *(head1)->stqh_last = (head2)->stqh_first;              \
 242                 (head1)->stqh_last = (head2)->stqh_last;                \
 243                 STAILQ_INIT((head2));                                   \
 244         }                                                               \
 245 } while (0)
 246
 247 #define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
 248
 249 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 250
 251 #define STAILQ_FOREACH(var, head, field)                                \
 252         for((var) = STAILQ_FIRST((head));                               \
 253            (var);                                                       \
 254            (var) = STAILQ_NEXT((var), field))
 255
 256
 257 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 258         for ((var) = STAILQ_FIRST((head));                              \
 259             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 260             (var) = (tvar))
 261
 262 #define STAILQ_INIT(head) do {                                          \
 263         STAILQ_FIRST((head)) = NULL;                                    \
 264         (head)->stqh_last = &STAILQ_FIRST((head));                      \
 265 } while (0)
 266
 267 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {               \
 268         if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
 269                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 270         STAILQ_NEXT((tqelm), field) = (elm);                            \
 271 } while (0)
 272
 273 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 274         if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
 275                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 276         STAILQ_FIRST((head)) = (elm);                                   \
 277 } while (0)
 278
 279 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 280         STAILQ_NEXT((elm), field) = NULL;                               \
 281         *(head)->stqh_last = (elm);                                     \
 282         (head)->stqh_last = &STAILQ_NEXT((elm), field);                 \
 283 } while (0)
 284
 285 #define STAILQ_LAST(head, type, field)                                  \
 286         (STAILQ_EMPTY((head)) ?                                         \
 287                 NULL :                                                  \
 288                 ((struct type *)(void *)                                \
 289                 ((char *)((head)->stqh_last) - __offsetof(struct type, field))))
 290
 291 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 292
 293 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 294         QMD_SAVELINK(oldnext, (elm)->field.stqe_next);                  \
 295         if (STAILQ_FIRST((head)) == (elm)) {                            \
 296                 STAILQ_REMOVE_HEAD((head), field);                      \
 297         }                                                               \
 298         else {                                                          \
 299                 struct type *curelm = STAILQ_FIRST((head));             \
 300                 while (STAILQ_NEXT(curelm, field) != (elm))             \
 301                         curelm = STAILQ_NEXT(curelm, field);            \
 302                 STAILQ_REMOVE_AFTER(head, curelm, field);               \
 303         }                                                               \
 304         TRASHIT(*oldnext);                                              \
 305 } while (0)
 306
 307 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 308         if ((STAILQ_FIRST((head)) =                                     \
 309              STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)         \
 310                 (head)->stqh_last = &STAILQ_FIRST((head));              \
 311 } while (0)
 312
 313 #define STAILQ_REMOVE_AFTER(head, elm, field) do {                      \
 314         if ((STAILQ_NEXT(elm, field) =                                  \
 315              STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)      \
 316                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 317 } while (0)
 318
 319 #define STAILQ_SWAP(head1, head2, type) do {                            \
 320         struct type *swap_first = STAILQ_FIRST(head1);                  \
 321         struct type **swap_last = (head1)->stqh_last;                   \
 322         STAILQ_FIRST(head1) = STAILQ_FIRST(head2);                      \
 323         (head1)->stqh_last = (head2)->stqh_last;                        \
 324         STAILQ_FIRST(head2) = swap_first;                               \
 325         (head2)->stqh_last = swap_last;                                 \
 326         if (STAILQ_EMPTY(head1))                                        \
 327                 (head1)->stqh_last = &STAILQ_FIRST(head1);              \
 328         if (STAILQ_EMPTY(head2))                                        \
 329                 (head2)->stqh_last = &STAILQ_FIRST(head2);              \
 330 } while (0)
 331
 332
 333 /*
 334  * List declarations.
 335  */
 336 #define LIST_HEAD(name, type)                                           \
 337 struct name {                                                           \
 338         struct type *lh_first;  /* first element */                     \
 339 }
 340
 341 #define LIST_HEAD_INITIALIZER(head)                                     \
 342         { NULL }
 343
 344 #define LIST_ENTRY(type)                                                \
 345 struct {                                                                \
 346         struct type *le_next;   /* next element */                      \
 347         struct type **le_prev;  /* address of previous next element */  \
 348 }
 349
 350 /*
 351  * List functions.
 352  */
 353
 354 #if (defined(_KERNEL) && defined(INVARIANTS))
 355 #define QMD_LIST_CHECK_HEAD(head, field) do {                           \
 356         if (LIST_FIRST((head)) != NULL &&                               \
 357             LIST_FIRST((head))->field.le_prev !=                        \
 358              &LIST_FIRST((head)))                                       \
 359                 panic("Bad list head %p first->prev != head", (head));  \
 360 } while (0)
 361
 362 #define QMD_LIST_CHECK_NEXT(elm, field) do {                            \
 363         if (LIST_NEXT((elm), field) != NULL &&                          \
 364             LIST_NEXT((elm), field)->field.le_prev !=                   \
 365              &((elm)->field.le_next))                                   \
 366                 panic("Bad link elm %p next->prev != elm", (elm));      \
 367 } while (0)
 368
 369 #define QMD_LIST_CHECK_PREV(elm, field) do {                            \
 370         if (*(elm)->field.le_prev != (elm))                             \
 371                 panic("Bad link elm %p prev->next != elm", (elm));      \
 372 } while (0)
 373 #else
 374 #define QMD_LIST_CHECK_HEAD(head, field)
 375 #define QMD_LIST_CHECK_NEXT(elm, field)
 376 #define QMD_LIST_CHECK_PREV(elm, field)
 377 #endif /* (_KERNEL && INVARIANTS) */
 378
 379 #define LIST_EMPTY(head)        ((head)->lh_first == NULL)
 380
 381 #define LIST_FIRST(head)        ((head)->lh_first)
 382
 383 #define LIST_FOREACH(var, head, field)                                  \
 384         for ((var) = LIST_FIRST((head));                                \
 385             (var);                                                      \
 386             (var) = LIST_NEXT((var), field))
 387
 388 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 389         for ((var) = LIST_FIRST((head));                                \
 390             (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 391             (var) = (tvar))
 392
 393 #define LIST_INIT(head) do {                                            \
 394         LIST_FIRST((head)) = NULL;                                      \
 395 } while (0)
 396
 397 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 398         QMD_LIST_CHECK_NEXT(listelm, field);                            \
 399         if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
 400                 LIST_NEXT((listelm), field)->field.le_prev =            \
 401                     &LIST_NEXT((elm), field);                           \
 402         LIST_NEXT((listelm), field) = (elm);                            \
 403         (elm)->field.le_prev = &LIST_NEXT((listelm), field);            \
 404 } while (0)
 405
 406 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 407         QMD_LIST_CHECK_PREV(listelm, field);                            \
 408         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 409         LIST_NEXT((elm), field) = (listelm);                            \
 410         *(listelm)->field.le_prev = (elm);                              \
 411         (listelm)->field.le_prev = &LIST_NEXT((elm), field);            \
 412 } while (0)
 413
 414 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 415         QMD_LIST_CHECK_HEAD((head), field);                             \
 416         if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)     \
 417                 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
 418         LIST_FIRST((head)) = (elm);                                     \
 419         (elm)->field.le_prev = &LIST_FIRST((head));                     \
 420 } while (0)
 421
 422 #define LIST_NEXT(elm, field)   ((elm)->field.le_next)
 423
 424 #define LIST_REMOVE(elm, field) do {                                    \
 425         QMD_SAVELINK(oldnext, (elm)->field.le_next);                    \
 426         QMD_SAVELINK(oldprev, (elm)->field.le_prev);                    \
 427         QMD_LIST_CHECK_NEXT(elm, field);                                \
 428         QMD_LIST_CHECK_PREV(elm, field);                                \
 429         if (LIST_NEXT((elm), field) != NULL)                            \
 430                 LIST_NEXT((elm), field)->field.le_prev =                \
 431                     (elm)->field.le_prev;                               \
 432         *(elm)->field.le_prev = LIST_NEXT((elm), field);                \
 433         TRASHIT(*oldnext);                                              \
 434         TRASHIT(*oldprev);                                              \
 435 } while (0)
 436
 437 #define LIST_SWAP(head1, head2, type, field) do {                       \
 438         struct type *swap_tmp = LIST_FIRST((head1));                    \
 439         LIST_FIRST((head1)) = LIST_FIRST((head2));                      \
 440         LIST_FIRST((head2)) = swap_tmp;                                 \
 441         if ((swap_tmp = LIST_FIRST((head1))) != NULL)                   \
 442                 swap_tmp->field.le_prev = &LIST_FIRST((head1));         \
 443         if ((swap_tmp = LIST_FIRST((head2))) != NULL)                   \
 444                 swap_tmp->field.le_prev = &LIST_FIRST((head2));         \
 445 } while (0)
 446
 447 /*
 448  * Tail queue declarations.
 449  */
 450 #define TAILQ_HEAD(name, type)                                          \
 451 struct name {                                                           \
 452         struct type *tqh_first; /* first element */                     \
 453         struct type **tqh_last; /* addr of last next element */         \
 454         TRACEBUF                                                        \
 455 }
 456
 457 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 458         { NULL, &(head).tqh_first }
 459
 460 #define TAILQ_ENTRY(type)                                               \
 461 struct {                                                                \
 462         struct type *tqe_next;  /* next element */                      \
 463         struct type **tqe_prev; /* address of previous next element */  \
 464         TRACEBUF                                                        \
 465 }
 466
 467 /*
 468  * Tail queue functions.
 469  */
 470 #if (defined(_KERNEL) && defined(INVARIANTS))
 471 #define QMD_TAILQ_CHECK_HEAD(head, field) do {                          \
 472         if (!TAILQ_EMPTY(head) &&                                       \
 473             TAILQ_FIRST((head))->field.tqe_prev !=                      \
 474              &TAILQ_FIRST((head)))                                      \
 475                 panic("Bad tailq head %p first->prev != head", (head)); \
 476 } while (0)
 477
 478 #define QMD_TAILQ_CHECK_TAIL(head, field) do {                          \
 479         if (*(head)->tqh_last != NULL)                                  \
 480                 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head));  \
 481 } while (0)
 482
 483 #define QMD_TAILQ_CHECK_NEXT(elm, field) do {                           \
 484         if (TAILQ_NEXT((elm), field) != NULL &&                         \
 485             TAILQ_NEXT((elm), field)->field.tqe_prev !=                 \
 486              &((elm)->field.tqe_next))                                  \
 487                 panic("Bad link elm %p next->prev != elm", (elm));      \
 488 } while (0)
 489
 490 #define QMD_TAILQ_CHECK_PREV(elm, field) do {                           \
 491         if (*(elm)->field.tqe_prev != (elm))                            \
 492                 panic("Bad link elm %p prev->next != elm", (elm));      \
 493 } while (0)
 494 #else
 495 #define QMD_TAILQ_CHECK_HEAD(head, field)
 496 #define QMD_TAILQ_CHECK_TAIL(head, headname)
 497 #define QMD_TAILQ_CHECK_NEXT(elm, field)
 498 #define QMD_TAILQ_CHECK_PREV(elm, field)
 499 #endif /* (_KERNEL && INVARIANTS) */
 500
 501 #define TAILQ_CONCAT(head1, head2, field) do {                          \
 502         if (!TAILQ_EMPTY(head2)) {                                      \
 503                 *(head1)->tqh_last = (head2)->tqh_first;                \
 504                 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 505                 (head1)->tqh_last = (head2)->tqh_last;                  \
 506                 TAILQ_INIT((head2));                                    \
 507                 QMD_TRACE_HEAD(head1);                                  \
 508                 QMD_TRACE_HEAD(head2);                                  \
 509         }                                                               \
 510 } while (0)
 511
 512 #define TAILQ_EMPTY(head)       ((head)->tqh_first == NULL)
 513
 514 #define TAILQ_FIRST(head)       ((head)->tqh_first)
 515
 516 #define TAILQ_FOREACH(var, head, field)                                 \
 517         for ((var) = TAILQ_FIRST((head));                               \
 518             (var);                                                      \
 519             (var) = TAILQ_NEXT((var), field))
 520
 521 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 522         for ((var) = TAILQ_FIRST((head));                               \
 523             (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 524             (var) = (tvar))
 525
 526 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 527         for ((var) = TAILQ_LAST((head), headname);                      \
 528             (var);                                                      \
 529             (var) = TAILQ_PREV((var), headname, field))
 530
 531 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 532         for ((var) = TAILQ_LAST((head), headname);                      \
 533             (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 534             (var) = (tvar))
 535
 536 #define TAILQ_INIT(head) do {                                           \
 537         TAILQ_FIRST((head)) = NULL;                                     \
 538         (head)->tqh_last = &TAILQ_FIRST((head));                        \
 539         QMD_TRACE_HEAD(head);                                           \
 540 } while (0)
 541
 542 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 543         QMD_TAILQ_CHECK_NEXT(listelm, field);                           \
 544         if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
 545                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 546                     &TAILQ_NEXT((elm), field);                          \
 547         else {                                                          \
 548                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 549                 QMD_TRACE_HEAD(head);                                   \
 550         }                                                               \
 551         TAILQ_NEXT((listelm), field) = (elm);                           \
 552         (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);          \
 553         QMD_TRACE_ELEM(&(elm)->field);                                  \
 554         QMD_TRACE_ELEM(&listelm->field);                                \
 555 } while (0)
 556
 557 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 558         QMD_TAILQ_CHECK_PREV(listelm, field);                           \
 559         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 560         TAILQ_NEXT((elm), field) = (listelm);                           \
 561         *(listelm)->field.tqe_prev = (elm);                             \
 562         (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);          \
 563         QMD_TRACE_ELEM(&(elm)->field);                                  \
 564         QMD_TRACE_ELEM(&listelm->field);                                \
 565 } while (0)
 566
 567 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 568         QMD_TAILQ_CHECK_HEAD(head, field);                              \
 569         if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)   \
 570                 TAILQ_FIRST((head))->field.tqe_prev =                   \
 571                     &TAILQ_NEXT((elm), field);                          \
 572         else                                                            \
 573                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 574         TAILQ_FIRST((head)) = (elm);                                    \
 575         (elm)->field.tqe_prev = &TAILQ_FIRST((head));                   \
 576         QMD_TRACE_HEAD(head);                                           \
 577         QMD_TRACE_ELEM(&(elm)->field);                                  \
 578 } while (0)
 579
 580 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 581         QMD_TAILQ_CHECK_TAIL(head, field);                              \
 582         TAILQ_NEXT((elm), field) = NULL;                                \
 583         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 584         *(head)->tqh_last = (elm);                                      \
 585         (head)->tqh_last = &TAILQ_NEXT((elm), field);                   \
 586         QMD_TRACE_HEAD(head);                                           \
 587         QMD_TRACE_ELEM(&(elm)->field);                                  \
 588 } while (0)
 589
 590 #define TAILQ_LAST(head, headname)                                      \
 591         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 592
 593 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 594
 595 #define TAILQ_PREV(elm, headname, field)                                \
 596         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 597
 598 #define TAILQ_REMOVE(head, elm, field) do {                             \
 599         QMD_SAVELINK(oldnext, (elm)->field.tqe_next);                   \
 600         QMD_SAVELINK(oldprev, (elm)->field.tqe_prev);                   \
 601         QMD_TAILQ_CHECK_NEXT(elm, field);                               \
 602         QMD_TAILQ_CHECK_PREV(elm, field);                               \
 603         if ((TAILQ_NEXT((elm), field)) != NULL)                         \
 604                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 605                     (elm)->field.tqe_prev;                              \
 606         else {                                                          \
 607                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 608                 QMD_TRACE_HEAD(head);                                   \
 609         }                                                               \
 610         *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);              \
 611         TRASHIT(*oldnext);                                              \
 612         TRASHIT(*oldprev);                                              \
 613         QMD_TRACE_ELEM(&(elm)->field);                                  \
 614 } while (0)
 615
 616 #define TAILQ_SWAP(head1, head2, type, field) do {                      \
 617         struct type *swap_first = (head1)->tqh_first;                   \
 618         struct type **swap_last = (head1)->tqh_last;                    \
 619         (head1)->tqh_first = (head2)->tqh_first;                        \
 620         (head1)->tqh_last = (head2)->tqh_last;                          \
 621         (head2)->tqh_first = swap_first;                                \
 622         (head2)->tqh_last = swap_last;                                  \
 623         if ((swap_first = (head1)->tqh_first) != NULL)                  \
 624                 swap_first->field.tqe_prev = &(head1)->tqh_first;       \
 625         else                                                            \
 626                 (head1)->tqh_last = &(head1)->tqh_first;                \
 627         if ((swap_first = (head2)->tqh_first) != NULL)                  \
 628                 swap_first->field.tqe_prev = &(head2)->tqh_first;       \
 629         else                                                            \
 630                 (head2)->tqh_last = &(head2)->tqh_first;                \
 631 } while (0)
 632
 633 #endif /* ROS_KERN_SYS_QUEUE_H */