drivers/usb/gadget/dwc_otg/dwc_list.h

   1 /*      $OpenBSD: queue.h,v 1.26 2004/05/04 16:59:32 grange Exp $       */
   2 /*      $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $       */
   3
   4 /*
   5  * Copyright (c) 1991, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      @(#)queue.h     8.5 (Berkeley) 8/20/94
  33  */
  34
  35 #ifndef _SYS_QUEUE_H_
  36 #define _SYS_QUEUE_H_
  37
  38
  39 /** @file
  40  *
  41  * This file defines linked list operations.  It is derived from BSD with
  42  * only the MACRO names being prefixed with DWC_.  This is because a few of
  43  * these names conflict with those on Linux.  For documentation on use, see the
  44  * inline comments in the source code.  The original license for this source
  45  * code applies and is preserved in the dwc_list.h source file.
  46  */
  47
  48 /*
  49  * This file defines five types of data structures: singly-linked lists,
  50  * lists, simple queues, tail queues, and circular queues.
  51  *
  52  *
  53  * A singly-linked list is headed by a single forward pointer. The elements
  54  * are singly linked for minimum space and pointer manipulation overhead at
  55  * the expense of O(n) removal for arbitrary elements. New elements can be
  56  * added to the list after an existing element or at the head of the list.
  57  * Elements being removed from the head of the list should use the explicit
  58  * macro for this purpose for optimum efficiency. A singly-linked list may
  59  * only be traversed in the forward direction.  Singly-linked lists are ideal
  60  * for applications with large datasets and few or no removals or for
  61  * implementing a LIFO 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 simple queue is headed by a pair of pointers, one the head of the
  71  * list and the other to the tail of the list. The elements are singly
  72  * linked to save space, so elements can only be removed from the
  73  * head of the list. New elements can be added to the list before or after
  74  * an existing element, at the head of the list, or at the end of the
  75  * list. A simple queue may only be traversed in the forward direction.
  76  *
  77  * A tail queue is headed by a pair of pointers, one to the head of the
  78  * list and the other to the tail of the list. The elements are doubly
  79  * linked so that an arbitrary element can be removed without a need to
  80  * traverse the list. New elements can be added to the list before or
  81  * after an existing element, at the head of the list, or at the end of
  82  * the list. A tail queue may be traversed in either direction.
  83  *
  84  * A circle queue is headed by a pair of pointers, one to the head of the
  85  * list and the other to the tail of the list. The elements are doubly
  86  * linked so that an arbitrary element can be removed without a need to
  87  * traverse the list. New elements can be added to the list before or after
  88  * an existing element, at the head of the list, or at the end of the list.
  89  * A circle queue may be traversed in either direction, but has a more
  90  * complex end of list detection.
  91  *
  92  * For details on the use of these macros, see the queue(3) manual page.
  93  */
  94
  95 /*
  96  * Double-linked List.
  97  */
  98
  99 typedef struct dwc_list_link {
 100         struct dwc_list_link *next;
 101         struct dwc_list_link *prev;
 102 } dwc_list_link_t;
 103
 104 #define DWC_LIST_INIT(link) do{         \
 105         (link)->next = (link);          \
 106         (link)->prev = (link);          \
 107 } while(0)
 108
 109 #define DWC_LIST_FIRST(link)    ((link)->next)
 110 #define DWC_LIST_LAST(link)     ((link)->prev)
 111 #define DWC_LIST_END(link)      (link)
 112 #define DWC_LIST_NEXT(link)     ((link)->next)
 113 #define DWC_LIST_PREV(link)     ((link)->prev)
 114 #define DWC_LIST_EMPTY(link)    \
 115         (DWC_LIST_FIRST(link) == DWC_LIST_END(link))
 116 #define DWC_LIST_ENTRY(link, type, field) (type *)              \
 117         ((uint8_t *)(link) - (size_t)(&((type *)0)->field))
 118
 119 #define DWC_LIST_INSERT_HEAD(list, link) do {                   \
 120         (link)->next = (list)->next;                            \
 121         (link)->prev = (list);                                  \
 122         (list)->next->prev = link;                              \
 123         (list)->next = link;                                    \
 124 } while(0)
 125
 126 #define DWC_LIST_INSERT_TAIL(list, link) do {                   \
 127         (link)->next = list;                                    \
 128         (link)->prev = (list)->prev;                            \
 129         (list)->prev->next = link;                              \
 130         (list)->prev = link;                                    \
 131 } while(0)
 132
 133 #define DWC_LIST_REMOVE(link) do {                              \
 134         (link)->next->prev = (link)->prev;                      \
 135         (link)->prev->next = (link)->next;                      \
 136 } while(0)
 137
 138 #define DWC_LIST_REMOVE_INIT(link) do {                         \
 139         DWC_LIST_REMOVE(link);                                  \
 140         DWC_LIST_INIT(link);                                    \
 141 } while(0)
 142
 143 #define DWC_LIST_MOVE_HEAD(list, link) do {                     \
 144         DWC_LIST_REMOVE(link);                                  \
 145         DWC_LIST_INSERT_HEAD(list, link);                       \
 146 } while(0)
 147
 148 #define DWC_LIST_MOVE_TAIL(list, link) do {                     \
 149         DWC_LIST_REMOVE(link);                                  \
 150         DWC_LIST_INSERT_TAIL(list, link);                       \
 151 } while(0)
 152
 153 #define DWC_LIST_FOREACH(var, list)                             \
 154         for((var) = DWC_LIST_FIRST(list);                       \
 155             (var) != DWC_LIST_END(list);                        \
 156             (var) = DWC_LIST_NEXT(var))
 157
 158 #define DWC_LIST_FOREACH_SAFE(var, var2, list)                  \
 159         for((var) = DWC_LIST_FIRST(list), var2 = DWC_LIST_NEXT(var);    \
 160             (var) != DWC_LIST_END(list);                        \
 161             (var) = (var2), var2 = DWC_LIST_NEXT(var2))
 162
 163 #define DWC_LIST_FOREACH_REVERSE(var, list)                     \
 164         for((var) = DWC_LIST_LAST(list);                        \
 165             (var) != DWC_LIST_END(list);                        \
 166             (var) = DWC_LIST_PREV(var))
 167
 168 /*
 169  * Singly-linked List definitions.
 170  */
 171 #define DWC_SLIST_HEAD(name, type)                                      \
 172 struct name {                                                           \
 173         struct type *slh_first; /* first element */                     \
 174 }
 175
 176 #define DWC_SLIST_HEAD_INITIALIZER(head)                                        \
 177         { NULL }
 178
 179 #define DWC_SLIST_ENTRY(type)                                           \
 180 struct {                                                                \
 181         struct type *sle_next;  /* next element */                      \
 182 }
 183
 184 /*
 185  * Singly-linked List access methods.
 186  */
 187 #define DWC_SLIST_FIRST(head)   ((head)->slh_first)
 188 #define DWC_SLIST_END(head)             NULL
 189 #define DWC_SLIST_EMPTY(head)   (SLIST_FIRST(head) == SLIST_END(head))
 190 #define DWC_SLIST_NEXT(elm, field)      ((elm)->field.sle_next)
 191
 192 #define DWC_SLIST_FOREACH(var, head, field)                                     \
 193         for((var) = SLIST_FIRST(head);                                  \
 194             (var) != SLIST_END(head);                                   \
 195             (var) = SLIST_NEXT(var, field))
 196
 197 #define DWC_SLIST_FOREACH_PREVPTR(var, varp, head, field)                       \
 198         for ((varp) = &SLIST_FIRST((head));                             \
 199             ((var) = *(varp)) != SLIST_END(head);                       \
 200             (varp) = &SLIST_NEXT((var), field))
 201
 202 /*
 203  * Singly-linked List functions.
 204  */
 205 #define DWC_SLIST_INIT(head) {                                          \
 206         SLIST_FIRST(head) = SLIST_END(head);                            \
 207 }
 208
 209 #define DWC_SLIST_INSERT_AFTER(slistelm, elm, field) do {                       \
 210         (elm)->field.sle_next = (slistelm)->field.sle_next;             \
 211         (slistelm)->field.sle_next = (elm);                             \
 212 } while (0)
 213
 214 #define DWC_SLIST_INSERT_HEAD(head, elm, field) do {                    \
 215         (elm)->field.sle_next = (head)->slh_first;                      \
 216         (head)->slh_first = (elm);                                      \
 217 } while (0)
 218
 219 #define DWC_SLIST_REMOVE_NEXT(head, elm, field) do {                    \
 220         (elm)->field.sle_next = (elm)->field.sle_next->field.sle_next;  \
 221 } while (0)
 222
 223 #define DWC_SLIST_REMOVE_HEAD(head, field) do {                         \
 224         (head)->slh_first = (head)->slh_first->field.sle_next;          \
 225 } while (0)
 226
 227 #define DWC_SLIST_REMOVE(head, elm, type, field) do {                   \
 228         if ((head)->slh_first == (elm)) {                               \
 229                 SLIST_REMOVE_HEAD((head), field);                       \
 230         }                                                               \
 231         else {                                                          \
 232                 struct type *curelm = (head)->slh_first;                \
 233                 while( curelm->field.sle_next != (elm) )                \
 234                         curelm = curelm->field.sle_next;                \
 235                 curelm->field.sle_next =                                \
 236                     curelm->field.sle_next->field.sle_next;             \
 237         }                                                               \
 238 } while (0)
 239
 240 #if 0
 241
 242 /*
 243  * List definitions.
 244  */
 245 #define DWC_LIST_HEAD(name, type)                                               \
 246 struct name {                                                           \
 247         struct type *lh_first;  /* first element */                     \
 248 }
 249
 250 #define DWC_LIST_HEAD_INITIALIZER(head)                                 \
 251         { NULL }
 252
 253 #define DWC_LIST_ENTRY(type)                                            \
 254 struct {                                                                \
 255         struct type *le_next;   /* next element */                      \
 256         struct type **le_prev;  /* address of previous next element */  \
 257 }
 258
 259 /*
 260  * List access methods
 261  */
 262 #define DWC_LIST_FIRST(head)            ((head)->lh_first)
 263 #define DWC_LIST_END(head)                      NULL
 264 #define DWC_LIST_EMPTY(head)            (DWC_LIST_FIRST(head) == DWC_LIST_END(head))
 265 #define DWC_LIST_NEXT(elm, field)               ((elm)->field.le_next)
 266
 267 #define DWC_LIST_FOREACH(var, head, field)                                      \
 268         for((var) = DWC_LIST_FIRST(head);                                       \
 269             (var)!= DWC_LIST_END(head);                                 \
 270             (var) = DWC_LIST_NEXT(var, field))
 271 #define DWC_LIST_FOREACH_SAFE(var, var2, head, field)                           \
 272         for((var) = DWC_LIST_FIRST(head), var2 = DWC_LIST_NEXT(var, field);                             \
 273             (var) != DWC_LIST_END(head);                                        \
 274             (var) = var2, var2 = DWC_LIST_NEXT(var, field))
 275
 276 /*
 277  * List functions.
 278  */
 279 #define DWC_LIST_INIT(head) do {                                                \
 280         DWC_LIST_FIRST(head) = DWC_LIST_END(head);                              \
 281 } while (0)
 282
 283 #define DWC_LIST_INSERT_AFTER(listelm, elm, field) do {                 \
 284         if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)  \
 285                 (listelm)->field.le_next->field.le_prev =               \
 286                     &(elm)->field.le_next;                              \
 287         (listelm)->field.le_next = (elm);                               \
 288         (elm)->field.le_prev = &(listelm)->field.le_next;               \
 289 } while (0)
 290
 291 #define DWC_LIST_INSERT_BEFORE(listelm, elm, field) do {                        \
 292         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 293         (elm)->field.le_next = (listelm);                               \
 294         *(listelm)->field.le_prev = (elm);                              \
 295         (listelm)->field.le_prev = &(elm)->field.le_next;               \
 296 } while (0)
 297
 298 #define DWC_LIST_INSERT_HEAD(head, elm, field) do {                             \
 299         if (((elm)->field.le_next = (head)->lh_first) != NULL)          \
 300                 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
 301         (head)->lh_first = (elm);                                       \
 302         (elm)->field.le_prev = &(head)->lh_first;                       \
 303 } while (0)
 304
 305 #define DWC_LIST_REMOVE(elm, field) do {                                        \
 306         if ((elm)->field.le_next != NULL)                               \
 307                 (elm)->field.le_next->field.le_prev =                   \
 308                     (elm)->field.le_prev;                               \
 309         *(elm)->field.le_prev = (elm)->field.le_next;                   \
 310 } while (0)
 311
 312 #define DWC_LIST_REPLACE(elm, elm2, field) do {                         \
 313         if (((elm2)->field.le_next = (elm)->field.le_next) != NULL)     \
 314                 (elm2)->field.le_next->field.le_prev =                  \
 315                     &(elm2)->field.le_next;                             \
 316         (elm2)->field.le_prev = (elm)->field.le_prev;                   \
 317         *(elm2)->field.le_prev = (elm2);                                \
 318 } while (0)
 319
 320 #endif
 321
 322 /*
 323  * Simple queue definitions.
 324  */
 325 #define DWC_SIMPLEQ_HEAD(name, type)                                    \
 326 struct name {                                                           \
 327         struct type *sqh_first; /* first element */                     \
 328         struct type **sqh_last; /* addr of last next element */         \
 329 }
 330
 331 #define DWC_SIMPLEQ_HEAD_INITIALIZER(head)                                      \
 332         { NULL, &(head).sqh_first }
 333
 334 #define DWC_SIMPLEQ_ENTRY(type)                                         \
 335 struct {                                                                \
 336         struct type *sqe_next;  /* next element */                      \
 337 }
 338
 339 /*
 340  * Simple queue access methods.
 341  */
 342 #define DWC_SIMPLEQ_FIRST(head)     ((head)->sqh_first)
 343 #define DWC_SIMPLEQ_END(head)       NULL
 344 #define DWC_SIMPLEQ_EMPTY(head)     (SIMPLEQ_FIRST(head) == SIMPLEQ_END(head))
 345 #define DWC_SIMPLEQ_NEXT(elm, field)    ((elm)->field.sqe_next)
 346
 347 #define DWC_SIMPLEQ_FOREACH(var, head, field)                           \
 348         for((var) = SIMPLEQ_FIRST(head);                                \
 349             (var) != SIMPLEQ_END(head);                                 \
 350             (var) = SIMPLEQ_NEXT(var, field))
 351
 352 /*
 353  * Simple queue functions.
 354  */
 355 #define DWC_SIMPLEQ_INIT(head) do {                                             \
 356         (head)->sqh_first = NULL;                                       \
 357         (head)->sqh_last = &(head)->sqh_first;                          \
 358 } while (0)
 359
 360 #define DWC_SIMPLEQ_INSERT_HEAD(head, elm, field) do {                  \
 361         if (((elm)->field.sqe_next = (head)->sqh_first) == NULL)        \
 362                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 363         (head)->sqh_first = (elm);                                      \
 364 } while (0)
 365
 366 #define DWC_SIMPLEQ_INSERT_TAIL(head, elm, field) do {                  \
 367         (elm)->field.sqe_next = NULL;                                   \
 368         *(head)->sqh_last = (elm);                                      \
 369         (head)->sqh_last = &(elm)->field.sqe_next;                      \
 370 } while (0)
 371
 372 #define DWC_SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do {                \
 373         if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
 374                 (head)->sqh_last = &(elm)->field.sqe_next;              \
 375         (listelm)->field.sqe_next = (elm);                              \
 376 } while (0)
 377
 378 #define DWC_SIMPLEQ_REMOVE_HEAD(head, field) do {                       \
 379         if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
 380                 (head)->sqh_last = &(head)->sqh_first;                  \
 381 } while (0)
 382
 383 /*
 384  * Tail queue definitions.
 385  */
 386 #define DWC_TAILQ_HEAD(name, type)                                              \
 387 struct name {                                                           \
 388         struct type *tqh_first; /* first element */                     \
 389         struct type **tqh_last; /* addr of last next element */         \
 390 }
 391
 392 #define DWC_TAILQ_HEAD_INITIALIZER(head)                                        \
 393         { NULL, &(head).tqh_first }
 394
 395 #define DWC_TAILQ_ENTRY(type)                                           \
 396 struct {                                                                \
 397         struct type *tqe_next;  /* next element */                      \
 398         struct type **tqe_prev; /* address of previous next element */  \
 399 }
 400
 401 /*
 402  * tail queue access methods
 403  */
 404 #define DWC_TAILQ_FIRST(head)           ((head)->tqh_first)
 405 #define DWC_TAILQ_END(head)                     NULL
 406 #define DWC_TAILQ_NEXT(elm, field)              ((elm)->field.tqe_next)
 407 #define DWC_TAILQ_LAST(head, headname)                                  \
 408         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 409 /* XXX */
 410 #define DWC_TAILQ_PREV(elm, headname, field)                            \
 411         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 412 #define DWC_TAILQ_EMPTY(head)                                           \
 413         (TAILQ_FIRST(head) == TAILQ_END(head))
 414
 415 #define DWC_TAILQ_FOREACH(var, head, field)                                     \
 416         for((var) = TAILQ_FIRST(head);                                  \
 417             (var) != TAILQ_END(head);                                   \
 418             (var) = TAILQ_NEXT(var, field))
 419
 420 #define DWC_TAILQ_FOREACH_REVERSE(var, head, headname, field)           \
 421         for((var) = TAILQ_LAST(head, headname);                         \
 422             (var) != TAILQ_END(head);                                   \
 423             (var) = TAILQ_PREV(var, headname, field))
 424
 425 /*
 426  * Tail queue functions.
 427  */
 428 #define DWC_TAILQ_INIT(head) do {                                               \
 429         (head)->tqh_first = NULL;                                       \
 430         (head)->tqh_last = &(head)->tqh_first;                          \
 431 } while (0)
 432
 433 #define DWC_TAILQ_INSERT_HEAD(head, elm, field) do {                    \
 434         if (((elm)->field.tqe_next = (head)->tqh_first) != NULL)        \
 435                 (head)->tqh_first->field.tqe_prev =                     \
 436                     &(elm)->field.tqe_next;                             \
 437         else                                                            \
 438                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 439         (head)->tqh_first = (elm);                                      \
 440         (elm)->field.tqe_prev = &(head)->tqh_first;                     \
 441 } while (0)
 442
 443 #define DWC_TAILQ_INSERT_TAIL(head, elm, field) do {                    \
 444         (elm)->field.tqe_next = NULL;                                   \
 445         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 446         *(head)->tqh_last = (elm);                                      \
 447         (head)->tqh_last = &(elm)->field.tqe_next;                      \
 448 } while (0)
 449
 450 #define DWC_TAILQ_INSERT_AFTER(head, listelm, elm, field) do {          \
 451         if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
 452                 (elm)->field.tqe_next->field.tqe_prev =                 \
 453                     &(elm)->field.tqe_next;                             \
 454         else                                                            \
 455                 (head)->tqh_last = &(elm)->field.tqe_next;              \
 456         (listelm)->field.tqe_next = (elm);                              \
 457         (elm)->field.tqe_prev = &(listelm)->field.tqe_next;             \
 458 } while (0)
 459
 460 #define DWC_TAILQ_INSERT_BEFORE(listelm, elm, field) do {                       \
 461         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 462         (elm)->field.tqe_next = (listelm);                              \
 463         *(listelm)->field.tqe_prev = (elm);                             \
 464         (listelm)->field.tqe_prev = &(elm)->field.tqe_next;             \
 465 } while (0)
 466
 467 #define DWC_TAILQ_REMOVE(head, elm, field) do {                         \
 468         if (((elm)->field.tqe_next) != NULL)                            \
 469                 (elm)->field.tqe_next->field.tqe_prev =                 \
 470                     (elm)->field.tqe_prev;                              \
 471         else                                                            \
 472                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 473         *(elm)->field.tqe_prev = (elm)->field.tqe_next;                 \
 474 } while (0)
 475
 476 #define DWC_TAILQ_REPLACE(head, elm, elm2, field) do {                  \
 477         if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL)   \
 478                 (elm2)->field.tqe_next->field.tqe_prev =                \
 479                     &(elm2)->field.tqe_next;                            \
 480         else                                                            \
 481                 (head)->tqh_last = &(elm2)->field.tqe_next;             \
 482         (elm2)->field.tqe_prev = (elm)->field.tqe_prev;                 \
 483         *(elm2)->field.tqe_prev = (elm2);                               \
 484 } while (0)
 485
 486 /*
 487  * Circular queue definitions.
 488  */
 489 #define DWC_CIRCLEQ_HEAD(name, type)                                    \
 490 struct name {                                                           \
 491         struct type *cqh_first;         /* first element */             \
 492         struct type *cqh_last;          /* last element */              \
 493 }
 494
 495 #define DWC_CIRCLEQ_HEAD_INITIALIZER(head)                                      \
 496         { DWC_CIRCLEQ_END(&head), DWC_CIRCLEQ_END(&head) }
 497
 498 #define DWC_CIRCLEQ_ENTRY(type)                                         \
 499 struct {                                                                \
 500         struct type *cqe_next;          /* next element */              \
 501         struct type *cqe_prev;          /* previous element */          \
 502 }
 503
 504 /*
 505  * Circular queue access methods
 506  */
 507 #define DWC_CIRCLEQ_FIRST(head)         ((head)->cqh_first)
 508 #define DWC_CIRCLEQ_LAST(head)          ((head)->cqh_last)
 509 #define DWC_CIRCLEQ_END(head)           ((void *)(head))
 510 #define DWC_CIRCLEQ_NEXT(elm, field)    ((elm)->field.cqe_next)
 511 #define DWC_CIRCLEQ_PREV(elm, field)    ((elm)->field.cqe_prev)
 512 #define DWC_CIRCLEQ_EMPTY(head)                                         \
 513         (DWC_CIRCLEQ_FIRST(head) == DWC_CIRCLEQ_END(head))
 514
 515 #define DWC_CIRCLEQ_EMPTY_ENTRY(elm, field) (((elm)->field.cqe_next == NULL) && ((elm)->field.cqe_prev == NULL))
 516
 517 #define DWC_CIRCLEQ_FOREACH(var, head, field)                           \
 518         for((var) = DWC_CIRCLEQ_FIRST(head);                            \
 519             (var) != DWC_CIRCLEQ_END(head);                                     \
 520             (var) = DWC_CIRCLEQ_NEXT(var, field))
 521
 522 #define DWC_CIRCLEQ_FOREACH_SAFE(var, var2, head, field)                                \
 523         for((var) = DWC_CIRCLEQ_FIRST(head), var2 = DWC_CIRCLEQ_NEXT(var, field);                               \
 524             (var) != DWC_CIRCLEQ_END(head);                                     \
 525             (var) = var2, var2 = DWC_CIRCLEQ_NEXT(var, field))
 526
 527 #define DWC_CIRCLEQ_FOREACH_REVERSE(var, head, field)                   \
 528         for((var) = DWC_CIRCLEQ_LAST(head);                                     \
 529             (var) != DWC_CIRCLEQ_END(head);                                     \
 530             (var) = DWC_CIRCLEQ_PREV(var, field))
 531
 532 /*
 533  * Circular queue functions.
 534  */
 535 #define DWC_CIRCLEQ_INIT(head) do {                                             \
 536         (head)->cqh_first = DWC_CIRCLEQ_END(head);                              \
 537         (head)->cqh_last = DWC_CIRCLEQ_END(head);                               \
 538 } while (0)
 539
 540 #define DWC_CIRCLEQ_INIT_ENTRY(elm, field) do { \
 541         (elm)->field.cqe_next = NULL; \
 542         (elm)->field.cqe_prev = NULL; \
 543 } while (0)
 544
 545 #define DWC_CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {                \
 546         (elm)->field.cqe_next = (listelm)->field.cqe_next;              \
 547         (elm)->field.cqe_prev = (listelm);                              \
 548         if ((listelm)->field.cqe_next == DWC_CIRCLEQ_END(head))         \
 549                 (head)->cqh_last = (elm);                               \
 550         else                                                            \
 551                 (listelm)->field.cqe_next->field.cqe_prev = (elm);      \
 552         (listelm)->field.cqe_next = (elm);                              \
 553 } while (0)
 554
 555 #define DWC_CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {               \
 556         (elm)->field.cqe_next = (listelm);                              \
 557         (elm)->field.cqe_prev = (listelm)->field.cqe_prev;              \
 558         if ((listelm)->field.cqe_prev == DWC_CIRCLEQ_END(head))         \
 559                 (head)->cqh_first = (elm);                              \
 560         else                                                            \
 561                 (listelm)->field.cqe_prev->field.cqe_next = (elm);      \
 562         (listelm)->field.cqe_prev = (elm);                              \
 563 } while (0)
 564
 565 #define DWC_CIRCLEQ_INSERT_HEAD(head, elm, field) do {                  \
 566         (elm)->field.cqe_next = (head)->cqh_first;                      \
 567         (elm)->field.cqe_prev = DWC_CIRCLEQ_END(head);                  \
 568         if ((head)->cqh_last == DWC_CIRCLEQ_END(head))                  \
 569                 (head)->cqh_last = (elm);                               \
 570         else                                                            \
 571                 (head)->cqh_first->field.cqe_prev = (elm);              \
 572         (head)->cqh_first = (elm);                                      \
 573 } while (0)
 574
 575 #define DWC_CIRCLEQ_INSERT_TAIL(head, elm, field) do {                  \
 576         (elm)->field.cqe_next = DWC_CIRCLEQ_END(head);                  \
 577         (elm)->field.cqe_prev = (head)->cqh_last;                       \
 578         if ((head)->cqh_first == DWC_CIRCLEQ_END(head))                 \
 579                 (head)->cqh_first = (elm);                              \
 580         else                                                            \
 581                 (head)->cqh_last->field.cqe_next = (elm);               \
 582         (head)->cqh_last = (elm);                                       \
 583 } while (0)
 584
 585 #define DWC_CIRCLEQ_REMOVE(head, elm, field) do {                               \
 586         if ((elm)->field.cqe_next == DWC_CIRCLEQ_END(head))                     \
 587                 (head)->cqh_last = (elm)->field.cqe_prev;               \
 588         else                                                            \
 589                 (elm)->field.cqe_next->field.cqe_prev =                 \
 590                     (elm)->field.cqe_prev;                              \
 591         if ((elm)->field.cqe_prev == DWC_CIRCLEQ_END(head))                     \
 592                 (head)->cqh_first = (elm)->field.cqe_next;              \
 593         else                                                            \
 594                 (elm)->field.cqe_prev->field.cqe_next =                 \
 595                     (elm)->field.cqe_next;                              \
 596 } while (0)
 597
 598 #define DWC_CIRCLEQ_REMOVE_INIT(head, elm, field) do { \
 599         DWC_CIRCLEQ_REMOVE(head, elm, field); \
 600         DWC_CIRCLEQ_INIT_ENTRY(elm, field); \
 601 } while (0)
 602
 603 #define DWC_CIRCLEQ_REPLACE(head, elm, elm2, field) do {                        \
 604         if (((elm2)->field.cqe_next = (elm)->field.cqe_next) ==         \
 605             DWC_CIRCLEQ_END(head))                                              \
 606                 (head).cqh_last = (elm2);                               \
 607         else                                                            \
 608                 (elm2)->field.cqe_next->field.cqe_prev = (elm2);        \
 609         if (((elm2)->field.cqe_prev = (elm)->field.cqe_prev) ==         \
 610             DWC_CIRCLEQ_END(head))                                              \
 611                 (head).cqh_first = (elm2);                              \
 612         else                                                            \
 613                 (elm2)->field.cqe_prev->field.cqe_next = (elm2);        \
 614 } while (0)
 615
 616 #endif  /* !_SYS_QUEUE_H_ */