bsd/sys/queue.h

0001 /*-
0002  * SPDX-License-Identifier: BSD-3-Clause
0003  *
0004  * Copyright (c) 1991, 1993
0005  *  The Regents of the University of California.  All rights reserved.
0006  *
0007  * Redistribution and use in source and binary forms, with or without
0008  * modification, are permitted provided that the following conditions
0009  * are met:
0010  * 1. Redistributions of source code must retain the above copyright
0011  *    notice, this list of conditions and the following disclaimer.
0012  * 2. Redistributions in binary form must reproduce the above copyright
0013  *    notice, this list of conditions and the following disclaimer in the
0014  *    documentation and/or other materials provided with the distribution.
0015  * 3. Neither the name of the University nor the names of its contributors
0016  *    may be used to endorse or promote products derived from this software
0017  *    without specific prior written permission.
0018  *
0019  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
0020  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0021  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0022  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
0023  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
0024  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
0025  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
0026  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
0027  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
0028  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
0029  * SUCH DAMAGE.
0030  *
0031  *  @(#)queue.h 8.5 (Berkeley) 8/20/94
0032  * $FreeBSD$
0033  */
0034
0035 #ifndef LIBBSD_SYS_QUEUE_H
0036 #define LIBBSD_SYS_QUEUE_H
0037
0038 #ifdef LIBBSD_OVERLAY
0039 #include <sys/cdefs.h>
0040 #else
0041 #include <bsd/sys/cdefs.h>
0042 #endif
0043
0044 /*
0045  * This file defines four types of data structures: singly-linked lists,
0046  * singly-linked tail queues, lists and tail queues.
0047  *
0048  * A singly-linked list is headed by a single forward pointer. The elements
0049  * are singly linked for minimum space and pointer manipulation overhead at
0050  * the expense of O(n) removal for arbitrary elements. New elements can be
0051  * added to the list after an existing element or at the head of the list.
0052  * Elements being removed from the head of the list should use the explicit
0053  * macro for this purpose for optimum efficiency. A singly-linked list may
0054  * only be traversed in the forward direction.  Singly-linked lists are ideal
0055  * for applications with large datasets and few or no removals or for
0056  * implementing a LIFO queue.
0057  *
0058  * A singly-linked tail queue is headed by a pair of pointers, one to the
0059  * head of the list and the other to the tail of the list. The elements are
0060  * singly linked for minimum space and pointer manipulation overhead at the
0061  * expense of O(n) removal for arbitrary elements. New elements can be added
0062  * to the list after an existing element, at the head of the list, or at the
0063  * end of the list. Elements being removed from the head of the tail queue
0064  * should use the explicit macro for this purpose for optimum efficiency.
0065  * A singly-linked tail queue may only be traversed in the forward direction.
0066  * Singly-linked tail queues are ideal for applications with large datasets
0067  * and few or no removals or for implementing a FIFO queue.
0068  *
0069  * A list is headed by a single forward pointer (or an array of forward
0070  * pointers for a hash table header). The elements are doubly linked
0071  * so that an arbitrary element can be removed without a need to
0072  * traverse the list. New elements can be added to the list before
0073  * or after an existing element or at the head of the list. A list
0074  * may be traversed in either direction.
0075  *
0076  * A tail queue is headed by a pair of pointers, one to the head of the
0077  * list and the other to the tail of the list. The elements are doubly
0078  * linked so that an arbitrary element can be removed without a need to
0079  * traverse the list. New elements can be added to the list before or
0080  * after an existing element, at the head of the list, or at the end of
0081  * the list. A tail queue may be traversed in either direction.
0082  *
0083  * For details on the use of these macros, see the queue(3) manual page.
0084  *
0085  * Below is a summary of implemented functions where:
0086  *  +  means the macro is available
0087  *  -  means the macro is not available
0088  *  s  means the macro is available but is slow (runs in O(n) time)
0089  *
0090  *              SLIST   LIST    STAILQ  TAILQ
0091  * _HEAD            +   +   +   +
0092  * _CLASS_HEAD          +   +   +   +
0093  * _HEAD_INITIALIZER        +   +   +   +
0094  * _ENTRY           +   +   +   +
0095  * _CLASS_ENTRY         +   +   +   +
0096  * _INIT            +   +   +   +
0097  * _EMPTY           +   +   +   +
0098  * _END             +   +   +   +
0099  * _FIRST           +   +   +   +
0100  * _NEXT            +   +   +   +
0101  * _PREV            -   +   -   +
0102  * _LAST            -   -   +   +
0103  * _LAST_FAST           -   -   -   +
0104  * _FOREACH         +   +   +   +
0105  * _FOREACH_FROM        +   +   +   +
0106  * _FOREACH_SAFE        +   +   +   +
0107  * _FOREACH_FROM_SAFE       +   +   +   +
0108  * _FOREACH_REVERSE     -   -   -   +
0109  * _FOREACH_REVERSE_FROM    -   -   -   +
0110  * _FOREACH_REVERSE_SAFE    -   -   -   +
0111  * _FOREACH_REVERSE_FROM_SAFE   -   -   -   +
0112  * _INSERT_HEAD         +   +   +   +
0113  * _INSERT_BEFORE       -   +   -   +
0114  * _INSERT_AFTER        +   +   +   +
0115  * _INSERT_TAIL         -   -   +   +
0116  * _CONCAT          s   s   +   +
0117  * _REMOVE_AFTER        +   -   +   -
0118  * _REMOVE_HEAD         +   -   +   -
0119  * _REMOVE          s   +   s   +
0120  * _SWAP            +   +   +   +
0121  *
0122  */
0123 #ifdef QUEUE_MACRO_DEBUG
0124 #warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH
0125 #define QUEUE_MACRO_DEBUG_TRACE
0126 #define QUEUE_MACRO_DEBUG_TRASH
0127 #endif
0128
0129 #ifdef QUEUE_MACRO_DEBUG_TRACE
0130 /* Store the last 2 places the queue element or head was altered */
0131 struct qm_trace {
0132     unsigned long    lastline;
0133     unsigned long    prevline;
0134     const char  *lastfile;
0135     const char  *prevfile;
0136 };
0137
0138 #define TRACEBUF    struct qm_trace trace;
0139 #define TRACEBUF_INITIALIZER    { __LINE__, 0, __FILE__, NULL } ,
0140
0141 #define QMD_TRACE_HEAD(head) do {                   \
0142     (head)->trace.prevline = (head)->trace.lastline;        \
0143     (head)->trace.prevfile = (head)->trace.lastfile;        \
0144     (head)->trace.lastline = __LINE__;              \
0145     (head)->trace.lastfile = __FILE__;              \
0146 } while (0)
0147
0148 #define QMD_TRACE_ELEM(elem) do {                   \
0149     (elem)->trace.prevline = (elem)->trace.lastline;        \
0150     (elem)->trace.prevfile = (elem)->trace.lastfile;        \
0151     (elem)->trace.lastline = __LINE__;              \
0152     (elem)->trace.lastfile = __FILE__;              \
0153 } while (0)
0154
0155 #else   /* !QUEUE_MACRO_DEBUG_TRACE */
0156 #define QMD_TRACE_ELEM(elem)
0157 #define QMD_TRACE_HEAD(head)
0158 #define TRACEBUF
0159 #define TRACEBUF_INITIALIZER
0160 #endif  /* QUEUE_MACRO_DEBUG_TRACE */
0161
0162 #ifdef QUEUE_MACRO_DEBUG_TRASH
0163 #define QMD_SAVELINK(name, link)    void **name = (void *)&(link)
0164 #define TRASHIT(x)      do {(x) = (void *)-1;} while (0)
0165 #define QMD_IS_TRASHED(x)   ((x) == (void *)(intptr_t)-1)
0166 #else   /* !QUEUE_MACRO_DEBUG_TRASH */
0167 #define QMD_SAVELINK(name, link)
0168 #define TRASHIT(x)
0169 #define QMD_IS_TRASHED(x)   0
0170 #endif  /* QUEUE_MACRO_DEBUG_TRASH */
0171
0172 #ifdef __cplusplus
0173 /*
0174  * In C++ there can be structure lists and class lists:
0175  */
0176 #define QUEUE_TYPEOF(type) type
0177 #else
0178 #define QUEUE_TYPEOF(type) struct type
0179 #endif
0180
0181 /*
0182  * Singly-linked List declarations.
0183  */
0184 #define SLIST_HEAD(name, type)                      \
0185 struct name {                               \
0186     struct type *slh_first; /* first element */         \
0187 }
0188
0189 #define SLIST_CLASS_HEAD(name, type)                    \
0190 struct name {                               \
0191     class type *slh_first;  /* first element */         \
0192 }
0193
0194 #define SLIST_HEAD_INITIALIZER(head)                    \
0195     { NULL }
0196
0197 #define SLIST_ENTRY(type)                       \
0198 struct {                                \
0199     struct type *sle_next;  /* next element */          \
0200 }
0201
0202 #define SLIST_CLASS_ENTRY(type)                     \
0203 struct {                                \
0204     class type *sle_next;       /* next element */      \
0205 }
0206
0207 /*
0208  * Singly-linked List functions.
0209  */
0210 #if (defined(_KERNEL) && defined(INVARIANTS))
0211 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do {            \
0212     if (*(prevp) != (elm))                      \
0213         panic("Bad prevptr *(%p) == %p != %p",          \
0214             (prevp), *(prevp), (elm));              \
0215 } while (0)
0216 #else
0217 #define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
0218 #endif
0219
0220 #define SLIST_CONCAT(head1, head2, type, field) do {            \
0221     QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1);        \
0222     if (curelm == NULL) {                       \
0223         if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL)  \
0224             SLIST_INIT(head2);              \
0225     } else if (SLIST_FIRST(head2) != NULL) {            \
0226         while (SLIST_NEXT(curelm, field) != NULL)       \
0227             curelm = SLIST_NEXT(curelm, field);     \
0228         SLIST_NEXT(curelm, field) = SLIST_FIRST(head2);     \
0229         SLIST_INIT(head2);                  \
0230     }                               \
0231 } while (0)
0232
0233 #define SLIST_EMPTY(head)   ((head)->slh_first == NULL)
0234
0235 #define SLIST_FIRST(head)   ((head)->slh_first)
0236
0237 #define SLIST_FOREACH(var, head, field)                 \
0238     for ((var) = SLIST_FIRST((head));               \
0239         (var);                          \
0240         (var) = SLIST_NEXT((var), field))
0241
0242 #define SLIST_FOREACH_FROM(var, head, field)                \
0243     for ((var) = ((var) ? (var) : SLIST_FIRST((head)));     \
0244         (var);                          \
0245         (var) = SLIST_NEXT((var), field))
0246
0247 #define SLIST_FOREACH_SAFE(var, head, field, tvar)          \
0248     for ((var) = SLIST_FIRST((head));               \
0249         (var) && ((tvar) = SLIST_NEXT((var), field), 1);        \
0250         (var) = (tvar))
0251
0252 #define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar)         \
0253     for ((var) = ((var) ? (var) : SLIST_FIRST((head)));     \
0254         (var) && ((tvar) = SLIST_NEXT((var), field), 1);        \
0255         (var) = (tvar))
0256
0257 #define SLIST_FOREACH_PREVPTR(var, varp, head, field)           \
0258     for ((varp) = &SLIST_FIRST((head));             \
0259         ((var) = *(varp)) != NULL;                  \
0260         (varp) = &SLIST_NEXT((var), field))
0261
0262 #define SLIST_INIT(head) do {                       \
0263     SLIST_FIRST((head)) = NULL;                 \
0264 } while (0)
0265
0266 #define SLIST_INSERT_AFTER(slistelm, elm, field) do {           \
0267     SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);   \
0268     SLIST_NEXT((slistelm), field) = (elm);              \
0269 } while (0)
0270
0271 #define SLIST_INSERT_HEAD(head, elm, field) do {            \
0272     SLIST_NEXT((elm), field) = SLIST_FIRST((head));         \
0273     SLIST_FIRST((head)) = (elm);                    \
0274 } while (0)
0275
0276 #define SLIST_NEXT(elm, field)  ((elm)->field.sle_next)
0277
0278 #define SLIST_REMOVE(head, elm, type, field) do {           \
0279     QMD_SAVELINK(oldnext, (elm)->field.sle_next);           \
0280     if (SLIST_FIRST((head)) == (elm)) {             \
0281         SLIST_REMOVE_HEAD((head), field);           \
0282     }                               \
0283     else {                              \
0284         QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head);     \
0285         while (SLIST_NEXT(curelm, field) != (elm))      \
0286             curelm = SLIST_NEXT(curelm, field);     \
0287         SLIST_REMOVE_AFTER(curelm, field);          \
0288     }                               \
0289     TRASHIT(*oldnext);                      \
0290 } while (0)
0291
0292 #define SLIST_REMOVE_AFTER(elm, field) do {             \
0293     SLIST_NEXT(elm, field) =                    \
0294         SLIST_NEXT(SLIST_NEXT(elm, field), field);          \
0295 } while (0)
0296
0297 #define SLIST_REMOVE_HEAD(head, field) do {             \
0298     SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);   \
0299 } while (0)
0300
0301 #define SLIST_REMOVE_PREVPTR(prevp, elm, field) do {            \
0302     QMD_SLIST_CHECK_PREVPTR(prevp, elm);                \
0303     *(prevp) = SLIST_NEXT(elm, field);              \
0304     TRASHIT((elm)->field.sle_next);                 \
0305 } while (0)
0306
0307 #define SLIST_SWAP(head1, head2, type) do {             \
0308     QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1);        \
0309     SLIST_FIRST(head1) = SLIST_FIRST(head2);            \
0310     SLIST_FIRST(head2) = swap_first;                \
0311 } while (0)
0312
0313 #define SLIST_END(head)     NULL
0314
0315 /*
0316  * Singly-linked Tail queue declarations.
0317  */
0318 #define STAILQ_HEAD(name, type)                     \
0319 struct name {                               \
0320     struct type *stqh_first;/* first element */         \
0321     struct type **stqh_last;/* addr of last next element */     \
0322 }
0323
0324 #define STAILQ_CLASS_HEAD(name, type)                   \
0325 struct name {                               \
0326     class type *stqh_first; /* first element */         \
0327     class type **stqh_last; /* addr of last next element */     \
0328 }
0329
0330 #define STAILQ_HEAD_INITIALIZER(head)                   \
0331     { NULL, &(head).stqh_first }
0332
0333 #define STAILQ_ENTRY(type)                      \
0334 struct {                                \
0335     struct type *stqe_next; /* next element */          \
0336 }
0337
0338 #define STAILQ_CLASS_ENTRY(type)                    \
0339 struct {                                \
0340     class type *stqe_next;  /* next element */          \
0341 }
0342
0343 /*
0344  * Singly-linked Tail queue functions.
0345  */
0346 #define STAILQ_CONCAT(head1, head2) do {                \
0347     if (!STAILQ_EMPTY((head2))) {                   \
0348         *(head1)->stqh_last = (head2)->stqh_first;      \
0349         (head1)->stqh_last = (head2)->stqh_last;        \
0350         STAILQ_INIT((head2));                   \
0351     }                               \
0352 } while (0)
0353
0354 #define STAILQ_EMPTY(head)  ((head)->stqh_first == NULL)
0355
0356 #define STAILQ_FIRST(head)  ((head)->stqh_first)
0357
0358 #define STAILQ_FOREACH(var, head, field)                \
0359     for((var) = STAILQ_FIRST((head));               \
0360        (var);                           \
0361        (var) = STAILQ_NEXT((var), field))
0362
0363 #define STAILQ_FOREACH_FROM(var, head, field)               \
0364     for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));        \
0365        (var);                           \
0366        (var) = STAILQ_NEXT((var), field))
0367
0368 #define STAILQ_FOREACH_SAFE(var, head, field, tvar)         \
0369     for ((var) = STAILQ_FIRST((head));              \
0370         (var) && ((tvar) = STAILQ_NEXT((var), field), 1);       \
0371         (var) = (tvar))
0372
0373 #define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)        \
0374     for ((var) = ((var) ? (var) : STAILQ_FIRST((head)));        \
0375         (var) && ((tvar) = STAILQ_NEXT((var), field), 1);       \
0376         (var) = (tvar))
0377
0378 #define STAILQ_INIT(head) do {                      \
0379     STAILQ_FIRST((head)) = NULL;                    \
0380     (head)->stqh_last = &STAILQ_FIRST((head));          \
0381 } while (0)
0382
0383 #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {       \
0384     if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
0385         (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
0386     STAILQ_NEXT((tqelm), field) = (elm);                \
0387 } while (0)
0388
0389 #define STAILQ_INSERT_HEAD(head, elm, field) do {           \
0390     if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
0391         (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
0392     STAILQ_FIRST((head)) = (elm);                   \
0393 } while (0)
0394
0395 #define STAILQ_INSERT_TAIL(head, elm, field) do {           \
0396     STAILQ_NEXT((elm), field) = NULL;               \
0397     *(head)->stqh_last = (elm);                 \
0398     (head)->stqh_last = &STAILQ_NEXT((elm), field);         \
0399 } while (0)
0400
0401 #define STAILQ_LAST(head, type, field)              \
0402     (STAILQ_EMPTY((head)) ? NULL :              \
0403         __containerof((head)->stqh_last,            \
0404         QUEUE_TYPEOF(type), field.stqe_next))
0405
0406 #define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
0407
0408 #define STAILQ_REMOVE(head, elm, type, field) do {          \
0409     QMD_SAVELINK(oldnext, (elm)->field.stqe_next);          \
0410     if (STAILQ_FIRST((head)) == (elm)) {                \
0411         STAILQ_REMOVE_HEAD((head), field);          \
0412     }                               \
0413     else {                              \
0414         QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head);    \
0415         while (STAILQ_NEXT(curelm, field) != (elm))     \
0416             curelm = STAILQ_NEXT(curelm, field);        \
0417         STAILQ_REMOVE_AFTER(head, curelm, field);       \
0418     }                               \
0419     TRASHIT(*oldnext);                      \
0420 } while (0)
0421
0422 #define STAILQ_REMOVE_AFTER(head, elm, field) do {          \
0423     if ((STAILQ_NEXT(elm, field) =                  \
0424          STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL)  \
0425         (head)->stqh_last = &STAILQ_NEXT((elm), field);     \
0426 } while (0)
0427
0428 #define STAILQ_REMOVE_HEAD(head, field) do {                \
0429     if ((STAILQ_FIRST((head)) =                 \
0430          STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)     \
0431         (head)->stqh_last = &STAILQ_FIRST((head));      \
0432 } while (0)
0433
0434 #define STAILQ_SWAP(head1, head2, type) do {                \
0435     QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1);       \
0436     QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last;        \
0437     STAILQ_FIRST(head1) = STAILQ_FIRST(head2);          \
0438     (head1)->stqh_last = (head2)->stqh_last;            \
0439     STAILQ_FIRST(head2) = swap_first;               \
0440     (head2)->stqh_last = swap_last;                 \
0441     if (STAILQ_EMPTY(head1))                    \
0442         (head1)->stqh_last = &STAILQ_FIRST(head1);      \
0443     if (STAILQ_EMPTY(head2))                    \
0444         (head2)->stqh_last = &STAILQ_FIRST(head2);      \
0445 } while (0)
0446
0447 #define STAILQ_END(head)    NULL
0448
0449
0450 /*
0451  * List declarations.
0452  */
0453 #define LIST_HEAD(name, type)                       \
0454 struct name {                               \
0455     struct type *lh_first;  /* first element */         \
0456 }
0457
0458 #define LIST_CLASS_HEAD(name, type)                 \
0459 struct name {                               \
0460     class type *lh_first;   /* first element */         \
0461 }
0462
0463 #define LIST_HEAD_INITIALIZER(head)                 \
0464     { NULL }
0465
0466 #define LIST_ENTRY(type)                        \
0467 struct {                                \
0468     struct type *le_next;   /* next element */          \
0469     struct type **le_prev;  /* address of previous next element */  \
0470 }
0471
0472 #define LIST_CLASS_ENTRY(type)                      \
0473 struct {                                \
0474     class type *le_next;    /* next element */          \
0475     class type **le_prev;   /* address of previous next element */  \
0476 }
0477
0478 /*
0479  * List functions.
0480  */
0481
0482 #if (defined(_KERNEL) && defined(INVARIANTS))
0483 /*
0484  * QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
0485  *
0486  * If the list is non-empty, validates that the first element of the list
0487  * points back at 'head.'
0488  */
0489 #define QMD_LIST_CHECK_HEAD(head, field) do {               \
0490     if (LIST_FIRST((head)) != NULL &&               \
0491         LIST_FIRST((head))->field.le_prev !=            \
0492          &LIST_FIRST((head)))                   \
0493         panic("Bad list head %p first->prev != head", (head));  \
0494 } while (0)
0495
0496 /*
0497  * QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
0498  *
0499  * If an element follows 'elm' in the list, validates that the next element
0500  * points back at 'elm.'
0501  */
0502 #define QMD_LIST_CHECK_NEXT(elm, field) do {                \
0503     if (LIST_NEXT((elm), field) != NULL &&              \
0504         LIST_NEXT((elm), field)->field.le_prev !=           \
0505          &((elm)->field.le_next))                   \
0506             panic("Bad link elm %p next->prev != elm", (elm));  \
0507 } while (0)
0508
0509 /*
0510  * QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
0511  *
0512  * Validates that the previous element (or head of the list) points to 'elm.'
0513  */
0514 #define QMD_LIST_CHECK_PREV(elm, field) do {                \
0515     if (*(elm)->field.le_prev != (elm))             \
0516         panic("Bad link elm %p prev->next != elm", (elm));  \
0517 } while (0)
0518 #else
0519 #define QMD_LIST_CHECK_HEAD(head, field)
0520 #define QMD_LIST_CHECK_NEXT(elm, field)
0521 #define QMD_LIST_CHECK_PREV(elm, field)
0522 #endif /* (_KERNEL && INVARIANTS) */
0523
0524 #define LIST_CONCAT(head1, head2, type, field) do {               \
0525     QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1);               \
0526     if (curelm == NULL) {                             \
0527         if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) {        \
0528             LIST_FIRST(head2)->field.le_prev =            \
0529                 &LIST_FIRST((head1));                 \
0530             LIST_INIT(head2);                     \
0531         }                                 \
0532     } else if (LIST_FIRST(head2) != NULL) {                   \
0533         while (LIST_NEXT(curelm, field) != NULL)              \
0534             curelm = LIST_NEXT(curelm, field);            \
0535         LIST_NEXT(curelm, field) = LIST_FIRST(head2);             \
0536         LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
0537         LIST_INIT(head2);                         \
0538     }                                     \
0539 } while (0)
0540
0541 #define LIST_EMPTY(head)    ((head)->lh_first == NULL)
0542
0543 #define LIST_FIRST(head)    ((head)->lh_first)
0544
0545 #define LIST_FOREACH(var, head, field)                  \
0546     for ((var) = LIST_FIRST((head));                \
0547         (var);                          \
0548         (var) = LIST_NEXT((var), field))
0549
0550 #define LIST_FOREACH_FROM(var, head, field)             \
0551     for ((var) = ((var) ? (var) : LIST_FIRST((head)));      \
0552         (var);                          \
0553         (var) = LIST_NEXT((var), field))
0554
0555 #define LIST_FOREACH_SAFE(var, head, field, tvar)           \
0556     for ((var) = LIST_FIRST((head));                \
0557         (var) && ((tvar) = LIST_NEXT((var), field), 1);     \
0558         (var) = (tvar))
0559
0560 #define LIST_FOREACH_FROM_SAFE(var, head, field, tvar)          \
0561     for ((var) = ((var) ? (var) : LIST_FIRST((head)));      \
0562         (var) && ((tvar) = LIST_NEXT((var), field), 1);     \
0563         (var) = (tvar))
0564
0565 #define LIST_INIT(head) do {                        \
0566     LIST_FIRST((head)) = NULL;                  \
0567 } while (0)
0568
0569 #define LIST_INSERT_AFTER(listelm, elm, field) do {         \
0570     QMD_LIST_CHECK_NEXT(listelm, field);                \
0571     if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
0572         LIST_NEXT((listelm), field)->field.le_prev =        \
0573             &LIST_NEXT((elm), field);               \
0574     LIST_NEXT((listelm), field) = (elm);                \
0575     (elm)->field.le_prev = &LIST_NEXT((listelm), field);        \
0576 } while (0)
0577
0578 #define LIST_INSERT_BEFORE(listelm, elm, field) do {            \
0579     QMD_LIST_CHECK_PREV(listelm, field);                \
0580     (elm)->field.le_prev = (listelm)->field.le_prev;        \
0581     LIST_NEXT((elm), field) = (listelm);                \
0582     *(listelm)->field.le_prev = (elm);              \
0583     (listelm)->field.le_prev = &LIST_NEXT((elm), field);        \
0584 } while (0)
0585
0586 #define LIST_INSERT_HEAD(head, elm, field) do {             \
0587     QMD_LIST_CHECK_HEAD((head), field);             \
0588     if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
0589         LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
0590     LIST_FIRST((head)) = (elm);                 \
0591     (elm)->field.le_prev = &LIST_FIRST((head));         \
0592 } while (0)
0593
0594 #define LIST_NEXT(elm, field)   ((elm)->field.le_next)
0595
0596 #define LIST_PREV(elm, head, type, field)           \
0597     ((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL :   \
0598         __containerof((elm)->field.le_prev,         \
0599         QUEUE_TYPEOF(type), field.le_next))
0600
0601 #define LIST_REMOVE(elm, field) do {                    \
0602     QMD_SAVELINK(oldnext, (elm)->field.le_next);            \
0603     QMD_SAVELINK(oldprev, (elm)->field.le_prev);            \
0604     QMD_LIST_CHECK_NEXT(elm, field);                \
0605     QMD_LIST_CHECK_PREV(elm, field);                \
0606     if (LIST_NEXT((elm), field) != NULL)                \
0607         LIST_NEXT((elm), field)->field.le_prev =        \
0608             (elm)->field.le_prev;               \
0609     *(elm)->field.le_prev = LIST_NEXT((elm), field);        \
0610     TRASHIT(*oldnext);                      \
0611     TRASHIT(*oldprev);                      \
0612 } while (0)
0613
0614 #define LIST_SWAP(head1, head2, type, field) do {           \
0615     QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1);       \
0616     LIST_FIRST((head1)) = LIST_FIRST((head2));          \
0617     LIST_FIRST((head2)) = swap_tmp;                 \
0618     if ((swap_tmp = LIST_FIRST((head1))) != NULL)           \
0619         swap_tmp->field.le_prev = &LIST_FIRST((head1));     \
0620     if ((swap_tmp = LIST_FIRST((head2))) != NULL)           \
0621         swap_tmp->field.le_prev = &LIST_FIRST((head2));     \
0622 } while (0)
0623
0624 #define LIST_END(head)  NULL
0625
0626 /*
0627  * Tail queue declarations.
0628  */
0629 #define TAILQ_HEAD(name, type)                      \
0630 struct name {                               \
0631     struct type *tqh_first; /* first element */         \
0632     struct type **tqh_last; /* addr of last next element */     \
0633     TRACEBUF                            \
0634 }
0635
0636 #define TAILQ_CLASS_HEAD(name, type)                    \
0637 struct name {                               \
0638     class type *tqh_first;  /* first element */         \
0639     class type **tqh_last;  /* addr of last next element */     \
0640     TRACEBUF                            \
0641 }
0642
0643 #define TAILQ_HEAD_INITIALIZER(head)                    \
0644     { NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
0645
0646 #define TAILQ_ENTRY(type)                       \
0647 struct {                                \
0648     struct type *tqe_next;  /* next element */          \
0649     struct type **tqe_prev; /* address of previous next element */  \
0650     TRACEBUF                            \
0651 }
0652
0653 #define TAILQ_CLASS_ENTRY(type)                     \
0654 struct {                                \
0655     class type *tqe_next;   /* next element */          \
0656     class type **tqe_prev;  /* address of previous next element */  \
0657     TRACEBUF                            \
0658 }
0659
0660 /*
0661  * Tail queue functions.
0662  */
0663 #if (defined(_KERNEL) && defined(INVARIANTS))
0664 /*
0665  * QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
0666  *
0667  * If the tailq is non-empty, validates that the first element of the tailq
0668  * points back at 'head.'
0669  */
0670 #define QMD_TAILQ_CHECK_HEAD(head, field) do {              \
0671     if (!TAILQ_EMPTY(head) &&                   \
0672         TAILQ_FIRST((head))->field.tqe_prev !=          \
0673          &TAILQ_FIRST((head)))                  \
0674         panic("Bad tailq head %p first->prev != head", (head)); \
0675 } while (0)
0676
0677 /*
0678  * QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
0679  *
0680  * Validates that the tail of the tailq is a pointer to pointer to NULL.
0681  */
0682 #define QMD_TAILQ_CHECK_TAIL(head, field) do {              \
0683     if (*(head)->tqh_last != NULL)                  \
0684             panic("Bad tailq NEXT(%p->tqh_last) != NULL", (head));  \
0685 } while (0)
0686
0687 /*
0688  * QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
0689  *
0690  * If an element follows 'elm' in the tailq, validates that the next element
0691  * points back at 'elm.'
0692  */
0693 #define QMD_TAILQ_CHECK_NEXT(elm, field) do {               \
0694     if (TAILQ_NEXT((elm), field) != NULL &&             \
0695         TAILQ_NEXT((elm), field)->field.tqe_prev !=         \
0696          &((elm)->field.tqe_next))                  \
0697         panic("Bad link elm %p next->prev != elm", (elm));  \
0698 } while (0)
0699
0700 /*
0701  * QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
0702  *
0703  * Validates that the previous element (or head of the tailq) points to 'elm.'
0704  */
0705 #define QMD_TAILQ_CHECK_PREV(elm, field) do {               \
0706     if (*(elm)->field.tqe_prev != (elm))                \
0707         panic("Bad link elm %p prev->next != elm", (elm));  \
0708 } while (0)
0709 #else
0710 #define QMD_TAILQ_CHECK_HEAD(head, field)
0711 #define QMD_TAILQ_CHECK_TAIL(head, headname)
0712 #define QMD_TAILQ_CHECK_NEXT(elm, field)
0713 #define QMD_TAILQ_CHECK_PREV(elm, field)
0714 #endif /* (_KERNEL && INVARIANTS) */
0715
0716 #define TAILQ_CONCAT(head1, head2, field) do {              \
0717     if (!TAILQ_EMPTY(head2)) {                  \
0718         *(head1)->tqh_last = (head2)->tqh_first;        \
0719         (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
0720         (head1)->tqh_last = (head2)->tqh_last;          \
0721         TAILQ_INIT((head2));                    \
0722         QMD_TRACE_HEAD(head1);                  \
0723         QMD_TRACE_HEAD(head2);                  \
0724     }                               \
0725 } while (0)
0726
0727 #define TAILQ_EMPTY(head)   ((head)->tqh_first == NULL)
0728
0729 #define TAILQ_FIRST(head)   ((head)->tqh_first)
0730
0731 #define TAILQ_FOREACH(var, head, field)                 \
0732     for ((var) = TAILQ_FIRST((head));               \
0733         (var);                          \
0734         (var) = TAILQ_NEXT((var), field))
0735
0736 #define TAILQ_FOREACH_FROM(var, head, field)                \
0737     for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));     \
0738         (var);                          \
0739         (var) = TAILQ_NEXT((var), field))
0740
0741 #define TAILQ_FOREACH_SAFE(var, head, field, tvar)          \
0742     for ((var) = TAILQ_FIRST((head));               \
0743         (var) && ((tvar) = TAILQ_NEXT((var), field), 1);        \
0744         (var) = (tvar))
0745
0746 #define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar)         \
0747     for ((var) = ((var) ? (var) : TAILQ_FIRST((head)));     \
0748         (var) && ((tvar) = TAILQ_NEXT((var), field), 1);        \
0749         (var) = (tvar))
0750
0751 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)       \
0752     for ((var) = TAILQ_LAST((head), headname);          \
0753         (var);                          \
0754         (var) = TAILQ_PREV((var), headname, field))
0755
0756 #define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field)      \
0757     for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
0758         (var);                          \
0759         (var) = TAILQ_PREV((var), headname, field))
0760
0761 #define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar)    \
0762     for ((var) = TAILQ_LAST((head), headname);          \
0763         (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
0764         (var) = (tvar))
0765
0766 #define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
0767     for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname));    \
0768         (var) && ((tvar) = TAILQ_PREV((var), headname, field), 1);  \
0769         (var) = (tvar))
0770
0771 #define TAILQ_INIT(head) do {                       \
0772     TAILQ_FIRST((head)) = NULL;                 \
0773     (head)->tqh_last = &TAILQ_FIRST((head));            \
0774     QMD_TRACE_HEAD(head);                       \
0775 } while (0)
0776
0777 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) do {      \
0778     QMD_TAILQ_CHECK_NEXT(listelm, field);               \
0779     if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
0780         TAILQ_NEXT((elm), field)->field.tqe_prev =      \
0781             &TAILQ_NEXT((elm), field);              \
0782     else {                              \
0783         (head)->tqh_last = &TAILQ_NEXT((elm), field);       \
0784         QMD_TRACE_HEAD(head);                   \
0785     }                               \
0786     TAILQ_NEXT((listelm), field) = (elm);               \
0787     (elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);      \
0788     QMD_TRACE_ELEM(&(elm)->field);                  \
0789     QMD_TRACE_ELEM(&(listelm)->field);              \
0790 } while (0)
0791
0792 #define TAILQ_INSERT_BEFORE(listelm, elm, field) do {           \
0793     QMD_TAILQ_CHECK_PREV(listelm, field);               \
0794     (elm)->field.tqe_prev = (listelm)->field.tqe_prev;      \
0795     TAILQ_NEXT((elm), field) = (listelm);               \
0796     *(listelm)->field.tqe_prev = (elm);             \
0797     (listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);      \
0798     QMD_TRACE_ELEM(&(elm)->field);                  \
0799     QMD_TRACE_ELEM(&(listelm)->field);              \
0800 } while (0)
0801
0802 #define TAILQ_INSERT_HEAD(head, elm, field) do {            \
0803     QMD_TAILQ_CHECK_HEAD(head, field);              \
0804     if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)   \
0805         TAILQ_FIRST((head))->field.tqe_prev =           \
0806             &TAILQ_NEXT((elm), field);              \
0807     else                                \
0808         (head)->tqh_last = &TAILQ_NEXT((elm), field);       \
0809     TAILQ_FIRST((head)) = (elm);                    \
0810     (elm)->field.tqe_prev = &TAILQ_FIRST((head));           \
0811     QMD_TRACE_HEAD(head);                       \
0812     QMD_TRACE_ELEM(&(elm)->field);                  \
0813 } while (0)
0814
0815 #define TAILQ_INSERT_TAIL(head, elm, field) do {            \
0816     QMD_TAILQ_CHECK_TAIL(head, field);              \
0817     TAILQ_NEXT((elm), field) = NULL;                \
0818     (elm)->field.tqe_prev = (head)->tqh_last;           \
0819     *(head)->tqh_last = (elm);                  \
0820     (head)->tqh_last = &TAILQ_NEXT((elm), field);           \
0821     QMD_TRACE_HEAD(head);                       \
0822     QMD_TRACE_ELEM(&(elm)->field);                  \
0823 } while (0)
0824
0825 #define TAILQ_LAST(head, headname)                  \
0826     (*(((struct headname *)((head)->tqh_last))->tqh_last))
0827
0828 /*
0829  * The FAST function is fast in that it causes no data access other
0830  * then the access to the head. The standard LAST function above
0831  * will cause a data access of both the element you want and
0832  * the previous element. FAST is very useful for instances when
0833  * you may want to prefetch the last data element.
0834  */
0835 #define TAILQ_LAST_FAST(head, type, field)          \
0836     (TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
0837
0838 #define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
0839
0840 #define TAILQ_PREV(elm, headname, field)                \
0841     (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
0842
0843 #define TAILQ_PREV_FAST(elm, head, type, field)             \
0844     ((elm)->field.tqe_prev == &(head)->tqh_first ? NULL :       \
0845      __containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
0846
0847 #define TAILQ_REMOVE(head, elm, field) do {             \
0848     QMD_SAVELINK(oldnext, (elm)->field.tqe_next);           \
0849     QMD_SAVELINK(oldprev, (elm)->field.tqe_prev);           \
0850     QMD_TAILQ_CHECK_NEXT(elm, field);               \
0851     QMD_TAILQ_CHECK_PREV(elm, field);               \
0852     if ((TAILQ_NEXT((elm), field)) != NULL)             \
0853         TAILQ_NEXT((elm), field)->field.tqe_prev =      \
0854             (elm)->field.tqe_prev;              \
0855     else {                              \
0856         (head)->tqh_last = (elm)->field.tqe_prev;       \
0857         QMD_TRACE_HEAD(head);                   \
0858     }                               \
0859     *(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);      \
0860     TRASHIT(*oldnext);                      \
0861     TRASHIT(*oldprev);                      \
0862     QMD_TRACE_ELEM(&(elm)->field);                  \
0863 } while (0)
0864
0865 #define TAILQ_SWAP(head1, head2, type, field) do {          \
0866     QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first;        \
0867     QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last;     \
0868     (head1)->tqh_first = (head2)->tqh_first;            \
0869     (head1)->tqh_last = (head2)->tqh_last;              \
0870     (head2)->tqh_first = swap_first;                \
0871     (head2)->tqh_last = swap_last;                  \
0872     if ((swap_first = (head1)->tqh_first) != NULL)          \
0873         swap_first->field.tqe_prev = &(head1)->tqh_first;   \
0874     else                                \
0875         (head1)->tqh_last = &(head1)->tqh_first;        \
0876     if ((swap_first = (head2)->tqh_first) != NULL)          \
0877         swap_first->field.tqe_prev = &(head2)->tqh_first;   \
0878     else                                \
0879         (head2)->tqh_last = &(head2)->tqh_first;        \
0880 } while (0)
0881
0882 #define TAILQ_END(head)     NULL
0883
0884 #endif /* !LIBBSD_SYS_QUEUE_H */