lib/librte_eal/windows/include/sys/queue.h

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  *
   3  * Copyright (c) 1991, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  */
   6
   7 #ifndef _SYS_QUEUE_H_
   8 #define _SYS_QUEUE_H_
   9
  10 /*
  11  * This file defines four types of data structures: singly-linked lists,
  12  * singly-linked tail queues, lists and tail queues.
  13  *
  14  * A singly-linked list is headed by a single forward pointer. The elements
  15  * are singly linked for minimum space and pointer manipulation overhead at
  16  * the expense of O(n) removal for arbitrary elements. New elements can be
  17  * added to the list after an existing element or at the head of the list.
  18  * Elements being removed from the head of the list should use the explicit
  19  * macro for this purpose for optimum efficiency. A singly-linked list may
  20  * only be traversed in the forward direction.  Singly-linked lists are ideal
  21  * for applications with large datasets and few or no removals or for
  22  * implementing a LIFO queue.
  23  *
  24  * A singly-linked tail queue is headed by a pair of pointers, one to the
  25  * head of the list and the other to the tail of the list. The elements are
  26  * singly linked for minimum space and pointer manipulation overhead at the
  27  * expense of O(n) removal for arbitrary elements. New elements can be added
  28  * to the list after an existing element, at the head of the list, or at the
  29  * end of the list. Elements being removed from the head of the tail queue
  30  * should use the explicit macro for this purpose for optimum efficiency.
  31  * A singly-linked tail queue may only be traversed in the forward direction.
  32  * Singly-linked tail queues are ideal for applications with large datasets
  33  * and few or no removals or for implementing a FIFO queue.
  34  *
  35  * A list is headed by a single forward pointer (or an array of forward
  36  * pointers for a hash table header). The elements are doubly linked
  37  * so that an arbitrary element can be removed without a need to
  38  * traverse the list. New elements can be added to the list before
  39  * or after an existing element or at the head of the list. A list
  40  * may be traversed in either direction.
  41  *
  42  * A tail queue is headed by a pair of pointers, one to the head of the
  43  * list and the other to the tail of the list. The elements are doubly
  44  * linked so that an arbitrary element can be removed without a need to
  45  * traverse the list. New elements can be added to the list before or
  46  * after an existing element, at the head of the list, or at the end of
  47  * the list. A tail queue may be traversed in either direction.
  48  *
  49  * For details on the use of these macros, see the queue(3) manual page.
  50  *
  51  * Below is a summary of implemented functions where:
  52  *  +  means the macro is available
  53  *  -  means the macro is not available
  54  *  s  means the macro is available but is slow (runs in O(n) time)
  55  *
  56  *                              SLIST   LIST    STAILQ  TAILQ
  57  * _HEAD                        +       +       +       +
  58  * _CLASS_HEAD                  +       +       +       +
  59  * _HEAD_INITIALIZER            +       +       +       +
  60  * _ENTRY                       +       +       +       +
  61  * _CLASS_ENTRY                 +       +       +       +
  62  * _INIT                        +       +       +       +
  63  * _EMPTY                       +       +       +       +
  64  * _FIRST                       +       +       +       +
  65  * _NEXT                        +       +       +       +
  66  * _PREV                        -       +       -       +
  67  * _LAST                        -       -       +       +
  68  * _LAST_FAST                   -       -       -       +
  69  * _FOREACH                     +       +       +       +
  70  * _FOREACH_FROM                +       +       +       +
  71  * _FOREACH_SAFE                +       +       +       +
  72  * _FOREACH_FROM_SAFE           +       +       +       +
  73  * _FOREACH_REVERSE             -       -       -       +
  74  * _FOREACH_REVERSE_FROM        -       -       -       +
  75  * _FOREACH_REVERSE_SAFE        -       -       -       +
  76  * _FOREACH_REVERSE_FROM_SAFE   -       -       -       +
  77  * _INSERT_HEAD                 +       +       +       +
  78  * _INSERT_BEFORE               -       +       -       +
  79  * _INSERT_AFTER                +       +       +       +
  80  * _INSERT_TAIL                 -       -       +       +
  81  * _CONCAT                      s       s       +       +
  82  * _REMOVE_AFTER                +       -       +       -
  83  * _REMOVE_HEAD                 +       -       +       -
  84  * _REMOVE                      s       +       s       +
  85  * _SWAP                        +       +       +       +
  86  *
  87  */
  88 #ifdef QUEUE_MACRO_DEBUG
  89 #warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH
  90 #define QUEUE_MACRO_DEBUG_TRACE
  91 #define QUEUE_MACRO_DEBUG_TRASH
  92 #endif
  93
  94 #ifdef QUEUE_MACRO_DEBUG_TRACE
  95 /* Store the last 2 places the queue element or head was altered */
  96 struct qm_trace {
  97         unsigned long    lastline;
  98         unsigned long    prevline;
  99         const char      *lastfile;
 100         const char      *prevfile;
 101 };
 102
 103 #define TRACEBUF        struct qm_trace trace;
 104 #define TRACEBUF_INITIALIZER    { __LINE__, 0, __FILE__, NULL } ,
 105
 106 #define QMD_TRACE_HEAD(head) do {                                       \
 107         (head)->trace.prevline = (head)->trace.lastline;                \
 108         (head)->trace.prevfile = (head)->trace.lastfile;                \
 109         (head)->trace.lastline = __LINE__;                              \
 110         (head)->trace.lastfile = __FILE__;                              \
 111 } while (0)
 112
 113 #define QMD_TRACE_ELEM(elem) do {                                       \
 114         (elem)->trace.prevline = (elem)->trace.lastline;                \
 115         (elem)->trace.prevfile = (elem)->trace.lastfile;                \
 116         (elem)->trace.lastline = __LINE__;                              \
 117         (elem)->trace.lastfile = __FILE__;                              \
 118 } while (0)
 119
 120 #else   /* !QUEUE_MACRO_DEBUG_TRACE */
 121 #define QMD_TRACE_ELEM(elem)
 122 #define QMD_TRACE_HEAD(head)
 123 #define TRACEBUF
 124 #define TRACEBUF_INITIALIZER
 125 #endif  /* QUEUE_MACRO_DEBUG_TRACE */
 126
 127 #ifdef QUEUE_MACRO_DEBUG_TRASH
 128 #define QMD_SAVELINK(name, link)        void **name = (void *)&(link)
 129 #define TRASHIT(x)              do {(x) = (void *)-1;} while (0)
 130 #define QMD_IS_TRASHED(x)       ((x) == (void *)(intptr_t)-1)
 131 #else   /* !QUEUE_MACRO_DEBUG_TRASH */
 132 #define QMD_SAVELINK(name, link)
 133 #define TRASHIT(x)
 134 #define QMD_IS_TRASHED(x)       0
 135 #endif  /* QUEUE_MACRO_DEBUG_TRASH */
 136
 137 #ifdef __cplusplus
 138 /*
 139  * In C++ there can be structure lists and class lists:
 140  */
 141 #define QUEUE_TYPEOF(type) type
 142 #else
 143 #define QUEUE_TYPEOF(type) struct type
 144 #endif
 145
 146 /*
 147  * Singly-linked List declarations.
 148  */
 149 #define SLIST_HEAD(name, type)                                          \
 150 struct name {                                                           \
 151         struct type *slh_first; /* first element */                     \
 152 }
 153
 154 #define SLIST_CLASS_HEAD(name, type)                                    \
 155 struct name {                                                           \
 156         class type *slh_first;  /* first element */                     \
 157 }
 158
 159 #define SLIST_HEAD_INITIALIZER(head)                                    \
 160         { NULL }
 161
 162 #define SLIST_ENTRY(type)                                               \
 163 struct {                                                                \
 164         struct type *sle_next;  /* next element */                      \
 165 }
 166
 167 #define SLIST_CLASS_ENTRY(type)                                         \
 168 struct {                                                                \
 169         class type *sle_next;           /* next element */              \
 170 }
 171
 172 /*
 173  * Singly-linked List functions.
 174  */
 175 #if (defined(_KERNEL) && defined(INVARIANTS))
 176 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do {                        \
 177         if (*(prevp) != (elm))                                          \
 178                 panic("Bad prevptr *(%p) == %p != %p",                  \
 179                     (prevp), *(prevp), (elm));                          \
 180 } while (0)
 181 #else
 182 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
 183 #endif
 184
 185 #define SLIST_CONCAT(head1, head2, type, field) do {                    \
 186         QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1);                \
 187         if (curelm == NULL) {                                           \
 188                 if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL)  \
 189                         SLIST_INIT(head2);                              \
 190         } else if (SLIST_FIRST(head2) != NULL) {                        \
 191                 while (SLIST_NEXT(curelm, field) != NULL)               \
 192                         curelm = SLIST_NEXT(curelm, field);             \
 193                 SLIST_NEXT(curelm, field) = SLIST_FIRST(head2);         \
 194                 SLIST_INIT(head2);                                      \
 195         }                                                               \
 196 } while (0)
 197
 198 #define SLIST_EMPTY(head)       ((head)->slh_first == NULL)
 199
 200 #define SLIST_FIRST(head)       ((head)->slh_first)
 201
 202 #define SLIST_FOREACH(var, head, field)                                 \
 203         for ((var) = SLIST_FIRST((head));                               \
 204             (var);                                                      \
 205             (var) = SLIST_NEXT((var), field))
 206
 207 #define SLIST_FOREACH_FROM(var, head, field)                            \
 208         for ((var) = ((var) ? (var) : SLIST_FIRST((head)));             \
 209             (var);                                                      \
 210             (var) = SLIST_NEXT((var), field))
 211
 212 #define SLIST_FOREACH_SAFE(var, head, field, tvar)                      \
 213         for ((var) = SLIST_FIRST((head));                               \
 214             (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 215             (var) = (tvar))
 216
 217 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar)                 \
 218         for ((var) = ((var) ? (var) : SLIST_FIRST((head)));             \
 219             (var) && ((tvar) = SLIST_NEXT((var), field), 1);            \
 220             (var) = (tvar))
 221
 222 #define SLIST_FOREACH_PREVPTR(var, varp, head, field)                   \
 223         for ((varp) = &SLIST_FIRST((head));                             \
 224             ((var) = *(varp)) != NULL;                                  \
 225             (varp) = &SLIST_NEXT((var), field))
 226
 227 #define SLIST_INIT(head) do {                                           \
 228         SLIST_FIRST((head)) = NULL;                                     \
 229 } while (0)
 230
 231 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {                   \
 232         SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);       \
 233         SLIST_NEXT((slistelm), field) = (elm);                          \
 234 } while (0)
 235
 236 #define SLIST_INSERT_HEAD(head, elm, field) do {                        \
 237         SLIST_NEXT((elm), field) = SLIST_FIRST((head));                 \
 238         SLIST_FIRST((head)) = (elm);                                    \
 239 } while (0)
 240
 241 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
 242
 243 #define SLIST_REMOVE(head, elm, type, field) do {                       \
 244         QMD_SAVELINK(oldnext, (elm)->field.sle_next);                   \
 245         if (SLIST_FIRST((head)) == (elm)) {                             \
 246                 SLIST_REMOVE_HEAD((head), field);                       \
 247         }                                                               \
 248         else {                                                          \
 249                 QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head);         \
 250                 while (SLIST_NEXT(curelm, field) != (elm))              \
 251                         curelm = SLIST_NEXT(curelm, field);             \
 252                 SLIST_REMOVE_AFTER(curelm, field);                      \
 253         }                                                               \
 254         TRASHIT(*oldnext);                                              \
 255 } while (0)
 256
 257 #define SLIST_REMOVE_AFTER(elm, field) do {                             \
 258         SLIST_NEXT(elm, field) =                                        \
 259             SLIST_NEXT(SLIST_NEXT(elm, field), field);                  \
 260 } while (0)
 261
 262 #define SLIST_REMOVE_HEAD(head, field) do {                             \
 263         SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
 264 } while (0)
 265
 266 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do {                    \
 267         QMD_SLIST_CHECK_PREVPTR(prevp, elm);                            \
 268         *(prevp) = SLIST_NEXT(elm, field);                              \
 269         TRASHIT((elm)->field.sle_next);                                 \
 270 } while (0)
 271
 272 #define SLIST_SWAP(head1, head2, type) do {                             \
 273         QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1);            \
 274         SLIST_FIRST(head1) = SLIST_FIRST(head2);                        \
 275         SLIST_FIRST(head2) = swap_first;                                \
 276 } while (0)
 277
 278 /*
 279  * Singly-linked Tail queue declarations.
 280  */
 281 #define STAILQ_HEAD(name, type)                                         \
 282 struct name {                                                           \
 283         struct type *stqh_first;/* first element */                     \
 284         struct type **stqh_last;/* addr of last next element */         \
 285 }
 286
 287 #define STAILQ_CLASS_HEAD(name, type)                                   \
 288 struct name {                                                           \
 289         class type *stqh_first; /* first element */                     \
 290         class type **stqh_last; /* addr of last next element */         \
 291 }
 292
 293 #define STAILQ_HEAD_INITIALIZER(head)                                   \
 294         { NULL, &(head).stqh_first }
 295
 296 #define STAILQ_ENTRY(type)                                              \
 297 struct {                                                                \
 298         struct type *stqe_next; /* next element */                      \
 299 }
 300
 301 #define STAILQ_CLASS_ENTRY(type)                                        \
 302 struct {                                                                \
 303         class type *stqe_next;  /* next element */                      \
 304 }
 305
 306 /*
 307  * Singly-linked Tail queue functions.
 308  */
 309 #define STAILQ_CONCAT(head1, head2) do {                                \
 310         if (!STAILQ_EMPTY((head2))) {                                   \
 311                 *(head1)->stqh_last = (head2)->stqh_first;              \
 312                 (head1)->stqh_last = (head2)->stqh_last;                \
 313                 STAILQ_INIT((head2));                                   \
 314         }                                                               \
 315 } while (0)
 316
 317 #define STAILQ_EMPTY(head)      ((head)->stqh_first == NULL)
 318
 319 #define STAILQ_FIRST(head)      ((head)->stqh_first)
 320
 321 #define STAILQ_FOREACH(var, head, field)                                \
 322         for((var) = STAILQ_FIRST((head));                               \
 323            (var);                                                       \
 324            (var) = STAILQ_NEXT((var), field))
 325
 326 #define STAILQ_FOREACH_FROM(var, head, field)                           \
 327         for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));            \
 328            (var);                                                       \
 329            (var) = STAILQ_NEXT((var), field))
 330
 331 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)                     \
 332         for ((var) = STAILQ_FIRST((head));                              \
 333             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 334             (var) = (tvar))
 335
 336 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)                \
 337         for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));            \
 338             (var) && ((tvar) = STAILQ_NEXT((var), field), 1);           \
 339             (var) = (tvar))
 340
 341 #define STAILQ_INIT(head) do {                                          \
 342         STAILQ_FIRST((head)) = NULL;                                    \
 343         (head)->stqh_last = &STAILQ_FIRST((head));                      \
 344 } while (0)
 345
 346 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {               \
 347         if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
 348                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 349         STAILQ_NEXT((tqelm), field) = (elm);                            \
 350 } while (0)
 351
 352 #define STAILQ_INSERT_HEAD(head, elm, field) do {                       \
 353         if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
 354                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 355         STAILQ_FIRST((head)) = (elm);                                   \
 356 } while (0)
 357
 358 #define STAILQ_INSERT_TAIL(head, elm, field) do {                       \
 359         STAILQ_NEXT((elm), field) = NULL;                               \
 360         *(head)->stqh_last = (elm);                                     \
 361         (head)->stqh_last = &STAILQ_NEXT((elm), field);                 \
 362 } while (0)
 363
 364 #define STAILQ_LAST(head, type, field)                          \
 365         (STAILQ_EMPTY((head)) ? NULL :                          \
 366             __containerof((head)->stqh_last,                    \
 367             QUEUE_TYPEOF(type), field.stqe_next))
 368
 369 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
 370
 371 #define STAILQ_REMOVE(head, elm, type, field) do {                      \
 372         QMD_SAVELINK(oldnext, (elm)->field.stqe_next);                  \
 373         if (STAILQ_FIRST((head)) == (elm)) {                            \
 374                 STAILQ_REMOVE_HEAD((head), field);                      \
 375         }                                                               \
 376         else {                                                          \
 377                 QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head);        \
 378                 while (STAILQ_NEXT(curelm, field) != (elm))             \
 379                         curelm = STAILQ_NEXT(curelm, field);            \
 380                 STAILQ_REMOVE_AFTER(head, curelm, field);               \
 381         }                                                               \
 382         TRASHIT(*oldnext);                                              \
 383 } while (0)
 384
 385 #define STAILQ_REMOVE_AFTER(head, elm, field) do {                      \
 386         if ((STAILQ_NEXT(elm, field) =                                  \
 387              STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)      \
 388                 (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
 389 } while (0)
 390
 391 #define STAILQ_REMOVE_HEAD(head, field) do {                            \
 392         if ((STAILQ_FIRST((head)) =                                     \
 393              STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)         \
 394                 (head)->stqh_last = &STAILQ_FIRST((head));              \
 395 } while (0)
 396
 397 #define STAILQ_SWAP(head1, head2, type) do {                            \
 398         QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1);           \
 399         QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last;            \
 400         STAILQ_FIRST(head1) = STAILQ_FIRST(head2);                      \
 401         (head1)->stqh_last = (head2)->stqh_last;                        \
 402         STAILQ_FIRST(head2) = swap_first;                               \
 403         (head2)->stqh_last = swap_last;                                 \
 404         if (STAILQ_EMPTY(head1))                                        \
 405                 (head1)->stqh_last = &STAILQ_FIRST(head1);              \
 406         if (STAILQ_EMPTY(head2))                                        \
 407                 (head2)->stqh_last = &STAILQ_FIRST(head2);              \
 408 } while (0)
 409
 410
 411 /*
 412  * List declarations.
 413  */
 414 #define LIST_HEAD(name, type)                                           \
 415 struct name {                                                           \
 416         struct type *lh_first;  /* first element */                     \
 417 }
 418
 419 #define LIST_CLASS_HEAD(name, type)                                     \
 420 struct name {                                                           \
 421         class type *lh_first;   /* first element */                     \
 422 }
 423
 424 #define LIST_HEAD_INITIALIZER(head)                                     \
 425         { NULL }
 426
 427 #define LIST_ENTRY(type)                                                \
 428 struct {                                                                \
 429         struct type *le_next;   /* next element */                      \
 430         struct type **le_prev;  /* address of previous next element */  \
 431 }
 432
 433 #define LIST_CLASS_ENTRY(type)                                          \
 434 struct {                                                                \
 435         class type *le_next;    /* next element */                      \
 436         class type **le_prev;   /* address of previous next element */  \
 437 }
 438
 439 /*
 440  * List functions.
 441  */
 442
 443 #if (defined(_KERNEL) && defined(INVARIANTS))
 444 /*
 445  * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
 446  *
 447  * If the list is non-empty, validates that the first element of the list
 448  * points back at 'head.'
 449  */
 450 #define QMD_LIST_CHECK_HEAD(head, field) do {                           \
 451         if (LIST_FIRST((head)) != NULL &&                               \
 452             LIST_FIRST((head))->field.le_prev !=                        \
 453              &LIST_FIRST((head)))                                       \
 454                 panic("Bad list head %p first->prev != head", (head));  \
 455 } while (0)
 456
 457 /*
 458  * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
 459  *
 460  * If an element follows 'elm' in the list, validates that the next element
 461  * points back at 'elm.'
 462  */
 463 #define QMD_LIST_CHECK_NEXT(elm, field) do {                            \
 464         if (LIST_NEXT((elm), field) != NULL &&                          \
 465             LIST_NEXT((elm), field)->field.le_prev !=                   \
 466              &((elm)->field.le_next))                                   \
 467                 panic("Bad link elm %p next->prev != elm", (elm));      \
 468 } while (0)
 469
 470 /*
 471  * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
 472  *
 473  * Validates that the previous element (or head of the list) points to 'elm.'
 474  */
 475 #define QMD_LIST_CHECK_PREV(elm, field) do {                            \
 476         if (*(elm)->field.le_prev != (elm))                             \
 477                 panic("Bad link elm %p prev->next != elm", (elm));      \
 478 } while (0)
 479 #else
 480 #define QMD_LIST_CHECK_HEAD(head, field)
 481 #define QMD_LIST_CHECK_NEXT(elm, field)
 482 #define QMD_LIST_CHECK_PREV(elm, field)
 483 #endif /* (_KERNEL && INVARIANTS) */
 484
 485 #define LIST_CONCAT(head1, head2, type, field) do {                           \
 486         QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1);                       \
 487         if (curelm == NULL) {                                                 \
 488                 if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) {        \
 489                         LIST_FIRST(head2)->field.le_prev =                    \
 490                             &LIST_FIRST((head1));                             \
 491                         LIST_INIT(head2);                                     \
 492                 }                                                             \
 493         } else if (LIST_FIRST(head2) != NULL) {                               \
 494                 while (LIST_NEXT(curelm, field) != NULL)                      \
 495                         curelm = LIST_NEXT(curelm, field);                    \
 496                 LIST_NEXT(curelm, field) = LIST_FIRST(head2);                 \
 497                 LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
 498                 LIST_INIT(head2);                                             \
 499         }                                                                     \
 500 } while (0)
 501
 502 #define LIST_EMPTY(head)        ((head)->lh_first == NULL)
 503
 504 #define LIST_FIRST(head)        ((head)->lh_first)
 505
 506 #define LIST_FOREACH(var, head, field)                                  \
 507         for ((var) = LIST_FIRST((head));                                \
 508             (var);                                                      \
 509             (var) = LIST_NEXT((var), field))
 510
 511 #define LIST_FOREACH_FROM(var, head, field)                             \
 512         for ((var) = ((var) ? (var) : LIST_FIRST((head)));              \
 513             (var);                                                      \
 514             (var) = LIST_NEXT((var), field))
 515
 516 #define LIST_FOREACH_SAFE(var, head, field, tvar)                       \
 517         for ((var) = LIST_FIRST((head));                                \
 518             (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 519             (var) = (tvar))
 520
 521 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar)                  \
 522         for ((var) = ((var) ? (var) : LIST_FIRST((head)));              \
 523             (var) && ((tvar) = LIST_NEXT((var), field), 1);             \
 524             (var) = (tvar))
 525
 526 #define LIST_INIT(head) do {                                            \
 527         LIST_FIRST((head)) = NULL;                                      \
 528 } while (0)
 529
 530 #define LIST_INSERT_AFTER(listelm, elm, field) do {                     \
 531         QMD_LIST_CHECK_NEXT(listelm, field);                            \
 532         if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
 533                 LIST_NEXT((listelm), field)->field.le_prev =            \
 534                     &LIST_NEXT((elm), field);                           \
 535         LIST_NEXT((listelm), field) = (elm);                            \
 536         (elm)->field.le_prev = &LIST_NEXT((listelm), field);            \
 537 } while (0)
 538
 539 #define LIST_INSERT_BEFORE(listelm, elm, field) do {                    \
 540         QMD_LIST_CHECK_PREV(listelm, field);                            \
 541         (elm)->field.le_prev = (listelm)->field.le_prev;                \
 542         LIST_NEXT((elm), field) = (listelm);                            \
 543         *(listelm)->field.le_prev = (elm);                              \
 544         (listelm)->field.le_prev = &LIST_NEXT((elm), field);            \
 545 } while (0)
 546
 547 #define LIST_INSERT_HEAD(head, elm, field) do {                         \
 548         QMD_LIST_CHECK_HEAD((head), field);                             \
 549         if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)     \
 550                 LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
 551         LIST_FIRST((head)) = (elm);                                     \
 552         (elm)->field.le_prev = &LIST_FIRST((head));                     \
 553 } while (0)
 554
 555 #define LIST_NEXT(elm, field)   ((elm)->field.le_next)
 556
 557 #define LIST_PREV(elm, head, type, field)                       \
 558         ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL :   \
 559             __containerof((elm)->field.le_prev,                 \
 560             QUEUE_TYPEOF(type), field.le_next))
 561
 562 #define LIST_REMOVE(elm, field) do {                                    \
 563         QMD_SAVELINK(oldnext, (elm)->field.le_next);                    \
 564         QMD_SAVELINK(oldprev, (elm)->field.le_prev);                    \
 565         QMD_LIST_CHECK_NEXT(elm, field);                                \
 566         QMD_LIST_CHECK_PREV(elm, field);                                \
 567         if (LIST_NEXT((elm), field) != NULL)                            \
 568                 LIST_NEXT((elm), field)->field.le_prev =                \
 569                     (elm)->field.le_prev;                               \
 570         *(elm)->field.le_prev = LIST_NEXT((elm), field);                \
 571         TRASHIT(*oldnext);                                              \
 572         TRASHIT(*oldprev);                                              \
 573 } while (0)
 574
 575 #define LIST_SWAP(head1, head2, type, field) do {                       \
 576         QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1);               \
 577         LIST_FIRST((head1)) = LIST_FIRST((head2));                      \
 578         LIST_FIRST((head2)) = swap_tmp;                                 \
 579         if ((swap_tmp = LIST_FIRST((head1))) != NULL)                   \
 580                 swap_tmp->field.le_prev = &LIST_FIRST((head1));         \
 581         if ((swap_tmp = LIST_FIRST((head2))) != NULL)                   \
 582                 swap_tmp->field.le_prev = &LIST_FIRST((head2));         \
 583 } while (0)
 584
 585 /*
 586  * Tail queue declarations.
 587  */
 588 #define TAILQ_HEAD(name, type)                                          \
 589 struct name {                                                           \
 590         struct type *tqh_first; /* first element */                     \
 591         struct type **tqh_last; /* addr of last next element */         \
 592         TRACEBUF                                                        \
 593 }
 594
 595 #define TAILQ_CLASS_HEAD(name, type)                                    \
 596 struct name {                                                           \
 597         class type *tqh_first;  /* first element */                     \
 598         class type **tqh_last;  /* addr of last next element */         \
 599         TRACEBUF                                                        \
 600 }
 601
 602 #define TAILQ_HEAD_INITIALIZER(head)                                    \
 603         { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
 604
 605 #define TAILQ_ENTRY(type)                                               \
 606 struct {                                                                \
 607         struct type *tqe_next;  /* next element */                      \
 608         struct type **tqe_prev; /* address of previous next element */  \
 609         TRACEBUF                                                        \
 610 }
 611
 612 #define TAILQ_CLASS_ENTRY(type)                                         \
 613 struct {                                                                \
 614         class type *tqe_next;   /* next element */                      \
 615         class type **tqe_prev;  /* address of previous next element */  \
 616         TRACEBUF                                                        \
 617 }
 618
 619 /*
 620  * Tail queue functions.
 621  */
 622 #if (defined(_KERNEL) && defined(INVARIANTS))
 623 /*
 624  * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
 625  *
 626  * If the tailq is non-empty, validates that the first element of the tailq
 627  * points back at 'head.'
 628  */
 629 #define QMD_TAILQ_CHECK_HEAD(head, field) do {                          \
 630         if (!TAILQ_EMPTY(head) &&                                       \
 631             TAILQ_FIRST((head))->field.tqe_prev !=                      \
 632              &TAILQ_FIRST((head)))                                      \
 633                 panic("Bad tailq head %p first->prev != head", (head)); \
 634 } while (0)
 635
 636 /*
 637  * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
 638  *
 639  * Validates that the tail of the tailq is a pointer to pointer to NULL.
 640  */
 641 #define QMD_TAILQ_CHECK_TAIL(head, field) do {                          \
 642         if (*(head)->tqh_last != NULL)                                  \
 643                 panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head));  \
 644 } while (0)
 645
 646 /*
 647  * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
 648  *
 649  * If an element follows 'elm' in the tailq, validates that the next element
 650  * points back at 'elm.'
 651  */
 652 #define QMD_TAILQ_CHECK_NEXT(elm, field) do {                           \
 653         if (TAILQ_NEXT((elm), field) != NULL &&                         \
 654             TAILQ_NEXT((elm), field)->field.tqe_prev !=                 \
 655              &((elm)->field.tqe_next))                                  \
 656                 panic("Bad link elm %p next->prev != elm", (elm));      \
 657 } while (0)
 658
 659 /*
 660  * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
 661  *
 662  * Validates that the previous element (or head of the tailq) points to 'elm.'
 663  */
 664 #define QMD_TAILQ_CHECK_PREV(elm, field) do {                           \
 665         if (*(elm)->field.tqe_prev != (elm))                            \
 666                 panic("Bad link elm %p prev->next != elm", (elm));      \
 667 } while (0)
 668 #else
 669 #define QMD_TAILQ_CHECK_HEAD(head, field)
 670 #define QMD_TAILQ_CHECK_TAIL(head, headname)
 671 #define QMD_TAILQ_CHECK_NEXT(elm, field)
 672 #define QMD_TAILQ_CHECK_PREV(elm, field)
 673 #endif /* (_KERNEL && INVARIANTS) */
 674
 675 #define TAILQ_CONCAT(head1, head2, field) do {                          \
 676         if (!TAILQ_EMPTY(head2)) {                                      \
 677                 *(head1)->tqh_last = (head2)->tqh_first;                \
 678                 (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
 679                 (head1)->tqh_last = (head2)->tqh_last;                  \
 680                 TAILQ_INIT((head2));                                    \
 681                 QMD_TRACE_HEAD(head1);                                  \
 682                 QMD_TRACE_HEAD(head2);                                  \
 683         }                                                               \
 684 } while (0)
 685
 686 #define TAILQ_EMPTY(head)       ((head)->tqh_first == NULL)
 687
 688 #define TAILQ_FIRST(head)       ((head)->tqh_first)
 689
 690 #define TAILQ_FOREACH(var, head, field)                                 \
 691         for ((var) = TAILQ_FIRST((head));                               \
 692             (var);                                                      \
 693             (var) = TAILQ_NEXT((var), field))
 694
 695 #define TAILQ_FOREACH_FROM(var, head, field)                            \
 696         for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));             \
 697             (var);                                                      \
 698             (var) = TAILQ_NEXT((var), field))
 699
 700 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
 701         for ((var) = TAILQ_FIRST((head));                               \
 702             (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 703             (var) = (tvar))
 704
 705 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)                 \
 706         for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));             \
 707             (var) && ((tvar) = TAILQ_NEXT((var), field), 1);            \
 708             (var) = (tvar))
 709
 710 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \
 711         for ((var) = TAILQ_LAST((head), headname);                      \
 712             (var);                                                      \
 713             (var) = TAILQ_PREV((var), headname, field))
 714
 715 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field)          \
 716         for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
 717             (var);                                                      \
 718             (var) = TAILQ_PREV((var), headname, field))
 719
 720 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
 721         for ((var) = TAILQ_LAST((head), headname);                      \
 722             (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 723             (var) = (tvar))
 724
 725 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
 726         for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
 727             (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
 728             (var) = (tvar))
 729
 730 #define TAILQ_INIT(head) do {                                           \
 731         TAILQ_FIRST((head)) = NULL;                                     \
 732         (head)->tqh_last = &TAILQ_FIRST((head));                        \
 733         QMD_TRACE_HEAD(head);                                           \
 734 } while (0)
 735
 736 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {              \
 737         QMD_TAILQ_CHECK_NEXT(listelm, field);                           \
 738         if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
 739                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 740                     &TAILQ_NEXT((elm), field);                          \
 741         else {                                                          \
 742                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 743                 QMD_TRACE_HEAD(head);                                   \
 744         }                                                               \
 745         TAILQ_NEXT((listelm), field) = (elm);                           \
 746         (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);          \
 747         QMD_TRACE_ELEM(&(elm)->field);                                  \
 748         QMD_TRACE_ELEM(&(listelm)->field);                              \
 749 } while (0)
 750
 751 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {                   \
 752         QMD_TAILQ_CHECK_PREV(listelm, field);                           \
 753         (elm)->field.tqe_prev = (listelm)->field.tqe_prev;              \
 754         TAILQ_NEXT((elm), field) = (listelm);                           \
 755         *(listelm)->field.tqe_prev = (elm);                             \
 756         (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);          \
 757         QMD_TRACE_ELEM(&(elm)->field);                                  \
 758         QMD_TRACE_ELEM(&(listelm)->field);                              \
 759 } while (0)
 760
 761 #define TAILQ_INSERT_HEAD(head, elm, field) do {                        \
 762         QMD_TAILQ_CHECK_HEAD(head, field);                              \
 763         if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)   \
 764                 TAILQ_FIRST((head))->field.tqe_prev =                   \
 765                     &TAILQ_NEXT((elm), field);                          \
 766         else                                                            \
 767                 (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
 768         TAILQ_FIRST((head)) = (elm);                                    \
 769         (elm)->field.tqe_prev = &TAILQ_FIRST((head));                   \
 770         QMD_TRACE_HEAD(head);                                           \
 771         QMD_TRACE_ELEM(&(elm)->field);                                  \
 772 } while (0)
 773
 774 #define TAILQ_INSERT_TAIL(head, elm, field) do {                        \
 775         QMD_TAILQ_CHECK_TAIL(head, field);                              \
 776         TAILQ_NEXT((elm), field) = NULL;                                \
 777         (elm)->field.tqe_prev = (head)->tqh_last;                       \
 778         *(head)->tqh_last = (elm);                                      \
 779         (head)->tqh_last = &TAILQ_NEXT((elm), field);                   \
 780         QMD_TRACE_HEAD(head);                                           \
 781         QMD_TRACE_ELEM(&(elm)->field);                                  \
 782 } while (0)
 783
 784 #define TAILQ_LAST(head, headname)                                      \
 785         (*(((struct headname *)((head)->tqh_last))->tqh_last))
 786
 787 /*
 788  * The FAST function is fast in that it causes no data access other
 789  * then the access to the head. The standard LAST function above
 790  * will cause a data access of both the element you want and
 791  * the previous element. FAST is very useful for instances when
 792  * you may want to prefetch the last data element.
 793  */
 794 #define TAILQ_LAST_FAST(head, type, field)                      \
 795     (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
 796
 797 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
 798
 799 #define TAILQ_PREV(elm, headname, field)                                \
 800         (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
 801
 802 #define TAILQ_PREV_FAST(elm, head, type, field)                         \
 803     ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL :               \
 804      __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
 805
 806 #define TAILQ_REMOVE(head, elm, field) do {                             \
 807         QMD_SAVELINK(oldnext, (elm)->field.tqe_next);                   \
 808         QMD_SAVELINK(oldprev, (elm)->field.tqe_prev);                   \
 809         QMD_TAILQ_CHECK_NEXT(elm, field);                               \
 810         QMD_TAILQ_CHECK_PREV(elm, field);                               \
 811         if ((TAILQ_NEXT((elm), field)) != NULL)                         \
 812                 TAILQ_NEXT((elm), field)->field.tqe_prev =              \
 813                     (elm)->field.tqe_prev;                              \
 814         else {                                                          \
 815                 (head)->tqh_last = (elm)->field.tqe_prev;               \
 816                 QMD_TRACE_HEAD(head);                                   \
 817         }                                                               \
 818         *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);              \
 819         TRASHIT(*oldnext);                                              \
 820         TRASHIT(*oldprev);                                              \
 821         QMD_TRACE_ELEM(&(elm)->field);                                  \
 822 } while (0)
 823
 824 #define TAILQ_SWAP(head1, head2, type, field) do {                      \
 825         QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first;            \
 826         QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last;             \
 827         (head1)->tqh_first = (head2)->tqh_first;                        \
 828         (head1)->tqh_last = (head2)->tqh_last;                          \
 829         (head2)->tqh_first = swap_first;                                \
 830         (head2)->tqh_last = swap_last;                                  \
 831         if ((swap_first = (head1)->tqh_first) != NULL)                  \
 832                 swap_first->field.tqe_prev = &(head1)->tqh_first;       \
 833         else                                                            \
 834                 (head1)->tqh_last = &(head1)->tqh_first;                \
 835         if ((swap_first = (head2)->tqh_first) != NULL)                  \
 836                 swap_first->field.tqe_prev = &(head2)->tqh_first;       \
 837         else                                                            \
 838                 (head2)->tqh_last = &(head2)->tqh_first;                \
 839 } while (0)
 840
 841 #endif /* !_SYS_QUEUE_H_ */