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2024-10-02-37-gfa9146
Teaching an old dog new tricks
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queue.h
Go to the documentation of this file.
1
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)queue.h 8.5 (Berkeley) 8/20/94
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* $FreeBSD$
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*/
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35
#ifndef _SYS_QUEUE_H_
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#define _SYS_QUEUE_H_
37
38
/*
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* This file defines four types of data structures: singly-linked lists,
40
* singly-linked tail queues, lists and tail queues.
41
*
42
* A singly-linked list is headed by a single forward pointer. The elements
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* are singly linked for minimum space and pointer manipulation overhead at
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* the expense of O(n) removal for arbitrary elements. New elements can be
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* added to the list after an existing element or at the head of the list.
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* Elements being removed from the head of the list should use the explicit
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* macro for this purpose for optimum efficiency. A singly-linked list may
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* only be traversed in the forward direction. Singly-linked lists are ideal
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* for applications with large datasets and few or no removals or for
50
* implementing a LIFO queue.
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*
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* A singly-linked tail queue is headed by a pair of pointers, one to the
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* head of the list and the other to the tail of the list. The elements are
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* singly linked for minimum space and pointer manipulation overhead at the
55
* expense of O(n) removal for arbitrary elements. New elements can be added
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* to the list after an existing element, at the head of the list, or at the
57
* end of the list. Elements being removed from the head of the tail queue
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* should use the explicit macro for this purpose for optimum efficiency.
59
* A singly-linked tail queue may only be traversed in the forward direction.
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* Singly-linked tail queues are ideal for applications with large datasets
61
* and few or no removals or for implementing a FIFO queue.
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*
63
* A list is headed by a single forward pointer (or an array of forward
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* 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
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* or after an existing element or at the head of the list. A list
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* may be traversed in either direction.
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*
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* A tail queue is headed by a pair of pointers, one to the head of the
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* list and the other to the tail of the list. The elements are doubly
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* linked so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before or
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* after an existing element, at the head of the list, or at the end of
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* the list. A tail queue may be traversed in either direction.
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*
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* For details on the use of these macros, see the queue(3) manual page.
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*
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* Below is a summary of implemented functions where:
80
* + means the macro is available
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* - means the macro is not available
82
* s means the macro is available but is slow (runs in O(n) time)
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*
84
* SLIST LIST STAILQ TAILQ
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* _HEAD + + + +
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* _CLASS_HEAD + + + +
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* _HEAD_INITIALIZER + + + +
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* _ENTRY + + + +
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* _CLASS_ENTRY + + + +
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* _INIT + + + +
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* _EMPTY + + + +
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* _END + + + +
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* _FIRST + + + +
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* _NEXT + + + +
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* _PREV - + - +
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* _LAST - - + +
97
* _LAST_FAST - - - +
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* _FOREACH + + + +
99
* _FOREACH_FROM + + + +
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* _FOREACH_SAFE + + + +
101
* _FOREACH_FROM_SAFE + + + +
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* _FOREACH_REVERSE - - - +
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* _FOREACH_REVERSE_FROM - - - +
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* _FOREACH_REVERSE_SAFE - - - +
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* _FOREACH_REVERSE_FROM_SAFE - - - +
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* _INSERT_HEAD + + + +
107
* _INSERT_BEFORE - + - +
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* _INSERT_AFTER + + + +
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* _INSERT_TAIL - - + +
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* _CONCAT s s + +
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* _REMOVE_AFTER + - + -
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* _REMOVE_HEAD + - + -
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* _REMOVE s + s +
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* _SWAP + + + +
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*
116
*/
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#ifdef QUEUE_MACRO_DEBUG
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#warn Use QUEUE_MACRO_DEBUG_TRACE and/or QUEUE_MACRO_DEBUG_TRASH
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#define QUEUE_MACRO_DEBUG_TRACE
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#define QUEUE_MACRO_DEBUG_TRASH
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#endif
122
123
#ifdef QUEUE_MACRO_DEBUG_TRACE
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/* Store the last 2 places the queue element or head was altered */
125
struct
qm_trace {
126
unsigned
long
lastline;
127
unsigned
long
prevline;
128
const
char
*lastfile;
129
const
char
*prevfile;
130
};
131
132
#define TRACEBUF struct qm_trace trace;
133
#define TRACEBUF_INITIALIZER { __LINE__, 0, __FILE__, NULL } ,
134
135
#define QMD_TRACE_HEAD(head) do { \
136
(head)->trace.prevline = (head)->trace.lastline; \
137
(head)->trace.prevfile = (head)->trace.lastfile; \
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(head)->trace.lastline = __LINE__; \
139
(head)->trace.lastfile = __FILE__; \
140
} while (0)
141
142
#define QMD_TRACE_ELEM(elem) do { \
143
(elem)->trace.prevline = (elem)->trace.lastline; \
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(elem)->trace.prevfile = (elem)->trace.lastfile; \
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(elem)->trace.lastline = __LINE__; \
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(elem)->trace.lastfile = __FILE__; \
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} while (0)
148
149
#else
/* !QUEUE_MACRO_DEBUG_TRACE */
150
#define QMD_TRACE_ELEM(elem)
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#define QMD_TRACE_HEAD(head)
152
#define TRACEBUF
153
#define TRACEBUF_INITIALIZER
154
#endif
/* QUEUE_MACRO_DEBUG_TRACE */
155
156
#ifdef QUEUE_MACRO_DEBUG_TRASH
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#define QMD_SAVELINK(name, link) void **name = (void *)&(link)
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#define TRASHIT(x) do {(x) = (void *)-1;} while (0)
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#define QMD_IS_TRASHED(x) ((x) == (void *)(intptr_t)-1)
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#else
/* !QUEUE_MACRO_DEBUG_TRASH */
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#define QMD_SAVELINK(name, link)
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#define TRASHIT(x)
163
#define QMD_IS_TRASHED(x) 0
164
#endif
/* QUEUE_MACRO_DEBUG_TRASH */
165
166
#ifdef __cplusplus
167
/*
168
* In C++ there can be structure lists and class lists:
169
*/
170
#define QUEUE_TYPEOF(type) type
171
#else
172
#define QUEUE_TYPEOF(type) struct type
173
#endif
174
175
/*
176
* Singly-linked List declarations.
177
*/
178
#define SLIST_HEAD(name, type) \
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struct name { \
180
struct type *slh_first;
/* first element */
\
181
}
182
183
#define SLIST_CLASS_HEAD(name, type) \
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struct name { \
185
class type *slh_first;
/* first element */
\
186
}
187
188
#define SLIST_HEAD_INITIALIZER(head) \
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{ NULL }
190
191
#define SLIST_ENTRY(type) \
192
struct { \
193
struct type *sle_next;
/* next element */
\
194
}
195
196
#define SLIST_CLASS_ENTRY(type) \
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struct { \
198
class type *sle_next;
/* next element */
\
199
}
200
201
/*
202
* Singly-linked List functions.
203
*/
204
#if (defined(_KERNEL) && defined(INVARIANTS))
205
#define QMD_SLIST_CHECK_PREVPTR(prevp, elm) do { \
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if (*(prevp) != (elm)) \
207
panic("Bad prevptr *(%p) == %p != %p"
, \
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(prevp), *(prevp), (elm)); \
209
} while (0)
210
#else
211
#define QMD_SLIST_CHECK_PREVPTR(prevp, elm)
212
#endif
213
214
#define SLIST_CONCAT(head1, head2, type, field) do { \
215
QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \
216
if (curelm == NULL) { \
217
if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \
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SLIST_INIT(head2); \
219
} else if (SLIST_FIRST(head2) != NULL) { \
220
while (SLIST_NEXT(curelm, field) != NULL) \
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curelm = SLIST_NEXT(curelm, field); \
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SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \
223
SLIST_INIT(head2); \
224
} \
225
} while (0)
226
227
#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
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229
#define SLIST_FIRST(head) ((head)->slh_first)
230
231
#define SLIST_FOREACH(var, head, field) \
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for ((var) = SLIST_FIRST((head)); \
233
(var); \
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(var) = SLIST_NEXT((var), field))
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236
#define SLIST_FOREACH_FROM(var, head, field) \
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for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
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(var); \
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(var) = SLIST_NEXT((var), field))
240
241
#define SLIST_FOREACH_SAFE(var, head, field, tvar) \
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for ((var) = SLIST_FIRST((head)); \
243
(var) && ((tvar) = SLIST_NEXT((var), field), 1); \
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(var) = (tvar))
245
246
#define SLIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
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for ((var) = ((var) ? (var) : SLIST_FIRST((head))); \
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(var) && ((tvar) = SLIST_NEXT((var), field), 1); \
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(var) = (tvar))
250
251
#define SLIST_FOREACH_PREVPTR(var, varp, head, field) \
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for ((varp) = &SLIST_FIRST((head)); \
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((var) = *(varp)) != NULL; \
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(varp) = &SLIST_NEXT((var), field))
255
256
#define SLIST_INIT(head) do { \
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SLIST_FIRST((head)) = NULL; \
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} while (0)
259
260
#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
261
SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
262
SLIST_NEXT((slistelm), field) = (elm); \
263
} while (0)
264
265
#define SLIST_INSERT_HEAD(head, elm, field) do { \
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SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
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SLIST_FIRST((head)) = (elm); \
268
} while (0)
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#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
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272
#define SLIST_REMOVE(head, elm, type, field) do { \
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QMD_SAVELINK(oldnext, (elm)->field.sle_next); \
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if (SLIST_FIRST((head)) == (elm)) { \
275
SLIST_REMOVE_HEAD((head), field); \
276
} \
277
else { \
278
QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head); \
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while (SLIST_NEXT(curelm, field) != (elm)) \
280
curelm = SLIST_NEXT(curelm, field); \
281
SLIST_REMOVE_AFTER(curelm, field); \
282
} \
283
TRASHIT(*oldnext); \
284
} while (0)
285
286
#define SLIST_REMOVE_AFTER(elm, field) do { \
287
SLIST_NEXT(elm, field) = \
288
SLIST_NEXT(SLIST_NEXT(elm, field), field); \
289
} while (0)
290
291
#define SLIST_REMOVE_HEAD(head, field) do { \
292
SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
293
} while (0)
294
295
#define SLIST_REMOVE_PREVPTR(prevp, elm, field) do { \
296
QMD_SLIST_CHECK_PREVPTR(prevp, elm); \
297
*(prevp) = SLIST_NEXT(elm, field); \
298
TRASHIT((elm)->field.sle_next); \
299
} while (0)
300
301
#define SLIST_SWAP(head1, head2, type) do { \
302
QUEUE_TYPEOF(type) *swap_first = SLIST_FIRST(head1); \
303
SLIST_FIRST(head1) = SLIST_FIRST(head2); \
304
SLIST_FIRST(head2) = swap_first; \
305
} while (0)
306
307
#define SLIST_END(head) NULL
308
309
/*
310
* Singly-linked Tail queue declarations.
311
*/
312
#define STAILQ_HEAD(name, type) \
313
struct name { \
314
struct type *stqh_first;
/* first element */
\
315
struct type **stqh_last;
/* addr of last next element */
\
316
}
317
318
#define STAILQ_CLASS_HEAD(name, type) \
319
struct name { \
320
class type *stqh_first;
/* first element */
\
321
class type **stqh_last;
/* addr of last next element */
\
322
}
323
324
#define STAILQ_HEAD_INITIALIZER(head) \
325
{ NULL, &(head).stqh_first }
326
327
#define STAILQ_ENTRY(type) \
328
struct { \
329
struct type *stqe_next;
/* next element */
\
330
}
331
332
#define STAILQ_CLASS_ENTRY(type) \
333
struct { \
334
class type *stqe_next;
/* next element */
\
335
}
336
337
/*
338
* Singly-linked Tail queue functions.
339
*/
340
#define STAILQ_CONCAT(head1, head2) do { \
341
if (!STAILQ_EMPTY((head2))) { \
342
*(head1)->stqh_last = (head2)->stqh_first; \
343
(head1)->stqh_last = (head2)->stqh_last; \
344
STAILQ_INIT((head2)); \
345
} \
346
} while (0)
347
348
#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
349
350
#define STAILQ_FIRST(head) ((head)->stqh_first)
351
352
#define STAILQ_FOREACH(var, head, field) \
353
for((var) = STAILQ_FIRST((head)); \
354
(var); \
355
(var) = STAILQ_NEXT((var), field))
356
357
#define STAILQ_FOREACH_FROM(var, head, field) \
358
for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
359
(var); \
360
(var) = STAILQ_NEXT((var), field))
361
362
#define STAILQ_FOREACH_SAFE(var, head, field, tvar) \
363
for ((var) = STAILQ_FIRST((head)); \
364
(var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
365
(var) = (tvar))
366
367
#define STAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
368
for ((var) = ((var) ? (var) : STAILQ_FIRST((head))); \
369
(var) && ((tvar) = STAILQ_NEXT((var), field), 1); \
370
(var) = (tvar))
371
372
#define STAILQ_INIT(head) do { \
373
STAILQ_FIRST((head)) = NULL; \
374
(head)->stqh_last = &STAILQ_FIRST((head)); \
375
} while (0)
376
377
#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
378
if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
379
(head)->stqh_last = &STAILQ_NEXT((elm), field); \
380
STAILQ_NEXT((tqelm), field) = (elm); \
381
} while (0)
382
383
#define STAILQ_INSERT_HEAD(head, elm, field) do { \
384
if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
385
(head)->stqh_last = &STAILQ_NEXT((elm), field); \
386
STAILQ_FIRST((head)) = (elm); \
387
} while (0)
388
389
#define STAILQ_INSERT_TAIL(head, elm, field) do { \
390
STAILQ_NEXT((elm), field) = NULL; \
391
*(head)->stqh_last = (elm); \
392
(head)->stqh_last = &STAILQ_NEXT((elm), field); \
393
} while (0)
394
395
#define STAILQ_LAST(head, type, field) \
396
(STAILQ_EMPTY((head)) ? NULL : \
397
__containerof((head)->stqh_last, \
398
QUEUE_TYPEOF(type), field.stqe_next))
399
400
#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
401
402
#define STAILQ_REMOVE(head, elm, type, field) do { \
403
QMD_SAVELINK(oldnext, (elm)->field.stqe_next); \
404
if (STAILQ_FIRST((head)) == (elm)) { \
405
STAILQ_REMOVE_HEAD((head), field); \
406
} \
407
else { \
408
QUEUE_TYPEOF(type) *curelm = STAILQ_FIRST(head); \
409
while (STAILQ_NEXT(curelm, field) != (elm)) \
410
curelm = STAILQ_NEXT(curelm, field); \
411
STAILQ_REMOVE_AFTER(head, curelm, field); \
412
} \
413
TRASHIT(*oldnext); \
414
} while (0)
415
416
#define STAILQ_REMOVE_AFTER(head, elm, field) do { \
417
if ((STAILQ_NEXT(elm, field) = \
418
STAILQ_NEXT(STAILQ_NEXT(elm, field), field)) == NULL) \
419
(head)->stqh_last = &STAILQ_NEXT((elm), field); \
420
} while (0)
421
422
#define STAILQ_REMOVE_HEAD(head, field) do { \
423
if ((STAILQ_FIRST((head)) = \
424
STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
425
(head)->stqh_last = &STAILQ_FIRST((head)); \
426
} while (0)
427
428
#define STAILQ_SWAP(head1, head2, type) do { \
429
QUEUE_TYPEOF(type) *swap_first = STAILQ_FIRST(head1); \
430
QUEUE_TYPEOF(type) **swap_last = (head1)->stqh_last; \
431
STAILQ_FIRST(head1) = STAILQ_FIRST(head2); \
432
(head1)->stqh_last = (head2)->stqh_last; \
433
STAILQ_FIRST(head2) = swap_first; \
434
(head2)->stqh_last = swap_last; \
435
if (STAILQ_EMPTY(head1)) \
436
(head1)->stqh_last = &STAILQ_FIRST(head1); \
437
if (STAILQ_EMPTY(head2)) \
438
(head2)->stqh_last = &STAILQ_FIRST(head2); \
439
} while (0)
440
441
#define STAILQ_END(head) NULL
442
443
444
/*
445
* List declarations.
446
*/
447
#define LIST_HEAD(name, type) \
448
struct name { \
449
struct type *lh_first;
/* first element */
\
450
}
451
452
#define LIST_CLASS_HEAD(name, type) \
453
struct name { \
454
class type *lh_first;
/* first element */
\
455
}
456
457
#define LIST_HEAD_INITIALIZER(head) \
458
{ NULL }
459
460
#define LIST_ENTRY(type) \
461
struct { \
462
struct type *le_next;
/* next element */
\
463
struct type **le_prev;
/* address of previous next element */
\
464
}
465
466
#define LIST_CLASS_ENTRY(type) \
467
struct { \
468
class type *le_next;
/* next element */
\
469
class type **le_prev;
/* address of previous next element */
\
470
}
471
472
/*
473
* List functions.
474
*/
475
476
#if (defined(_KERNEL) && defined(INVARIANTS))
477
/*
478
* QMD_LIST_CHECK_HEAD(LIST_HEAD *head, LIST_ENTRY NAME)
479
*
480
* If the list is non-empty, validates that the first element of the list
481
* points back at 'head.'
482
*/
483
#define QMD_LIST_CHECK_HEAD(head, field) do { \
484
if (LIST_FIRST((head)) != NULL && \
485
LIST_FIRST((head))->field.le_prev != \
486
&LIST_FIRST((head))) \
487
panic("Bad list head %p first->prev != head"
, (head)); \
488
} while (0)
489
490
/*
491
* QMD_LIST_CHECK_NEXT(TYPE *elm, LIST_ENTRY NAME)
492
*
493
* If an element follows 'elm' in the list, validates that the next element
494
* points back at 'elm.'
495
*/
496
#define QMD_LIST_CHECK_NEXT(elm, field) do { \
497
if (LIST_NEXT((elm), field) != NULL && \
498
LIST_NEXT((elm), field)->field.le_prev != \
499
&((elm)->field.le_next)) \
500
panic("Bad link elm %p next->prev != elm"
, (elm)); \
501
} while (0)
502
503
/*
504
* QMD_LIST_CHECK_PREV(TYPE *elm, LIST_ENTRY NAME)
505
*
506
* Validates that the previous element (or head of the list) points to 'elm.'
507
*/
508
#define QMD_LIST_CHECK_PREV(elm, field) do { \
509
if (*(elm)->field.le_prev != (elm)) \
510
panic("Bad link elm %p prev->next != elm"
, (elm)); \
511
} while (0)
512
#else
513
#define QMD_LIST_CHECK_HEAD(head, field)
514
#define QMD_LIST_CHECK_NEXT(elm, field)
515
#define QMD_LIST_CHECK_PREV(elm, field)
516
#endif
/* (_KERNEL && INVARIANTS) */
517
518
#define LIST_CONCAT(head1, head2, type, field) do { \
519
QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
520
if (curelm == NULL) { \
521
if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
522
LIST_FIRST(head2)->field.le_prev = \
523
&LIST_FIRST((head1)); \
524
LIST_INIT(head2); \
525
} \
526
} else if (LIST_FIRST(head2) != NULL) { \
527
while (LIST_NEXT(curelm, field) != NULL) \
528
curelm = LIST_NEXT(curelm, field); \
529
LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
530
LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
531
LIST_INIT(head2); \
532
} \
533
} while (0)
534
535
#define LIST_EMPTY(head) ((head)->lh_first == NULL)
536
537
#define LIST_FIRST(head) ((head)->lh_first)
538
539
#define LIST_FOREACH(var, head, field) \
540
for ((var) = LIST_FIRST((head)); \
541
(var); \
542
(var) = LIST_NEXT((var), field))
543
544
#define LIST_FOREACH_FROM(var, head, field) \
545
for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
546
(var); \
547
(var) = LIST_NEXT((var), field))
548
549
#define LIST_FOREACH_SAFE(var, head, field, tvar) \
550
for ((var) = LIST_FIRST((head)); \
551
(var) && ((tvar) = LIST_NEXT((var), field), 1); \
552
(var) = (tvar))
553
554
#define LIST_FOREACH_FROM_SAFE(var, head, field, tvar) \
555
for ((var) = ((var) ? (var) : LIST_FIRST((head))); \
556
(var) && ((tvar) = LIST_NEXT((var), field), 1); \
557
(var) = (tvar))
558
559
#define LIST_INIT(head) do { \
560
LIST_FIRST((head)) = NULL; \
561
} while (0)
562
563
#define LIST_INSERT_AFTER(listelm, elm, field) do { \
564
QMD_LIST_CHECK_NEXT(listelm, field); \
565
if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
566
LIST_NEXT((listelm), field)->field.le_prev = \
567
&LIST_NEXT((elm), field); \
568
LIST_NEXT((listelm), field) = (elm); \
569
(elm)->field.le_prev = &LIST_NEXT((listelm), field); \
570
} while (0)
571
572
#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
573
QMD_LIST_CHECK_PREV(listelm, field); \
574
(elm)->field.le_prev = (listelm)->field.le_prev; \
575
LIST_NEXT((elm), field) = (listelm); \
576
*(listelm)->field.le_prev = (elm); \
577
(listelm)->field.le_prev = &LIST_NEXT((elm), field); \
578
} while (0)
579
580
#define LIST_INSERT_HEAD(head, elm, field) do { \
581
QMD_LIST_CHECK_HEAD((head), field); \
582
if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
583
LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
584
LIST_FIRST((head)) = (elm); \
585
(elm)->field.le_prev = &LIST_FIRST((head)); \
586
} while (0)
587
588
#define LIST_NEXT(elm, field) ((elm)->field.le_next)
589
590
#define LIST_PREV(elm, head, type, field) \
591
((elm)->field.le_prev == &LIST_FIRST((head)) ? NULL : \
592
__containerof((elm)->field.le_prev, \
593
QUEUE_TYPEOF(type), field.le_next))
594
595
#define LIST_REMOVE(elm, field) do { \
596
QMD_SAVELINK(oldnext, (elm)->field.le_next); \
597
QMD_SAVELINK(oldprev, (elm)->field.le_prev); \
598
QMD_LIST_CHECK_NEXT(elm, field); \
599
QMD_LIST_CHECK_PREV(elm, field); \
600
if (LIST_NEXT((elm), field) != NULL) \
601
LIST_NEXT((elm), field)->field.le_prev = \
602
(elm)->field.le_prev; \
603
*(elm)->field.le_prev = LIST_NEXT((elm), field); \
604
TRASHIT(*oldnext); \
605
TRASHIT(*oldprev); \
606
} while (0)
607
608
#define LIST_SWAP(head1, head2, type, field) do { \
609
QUEUE_TYPEOF(type) *swap_tmp = LIST_FIRST(head1); \
610
LIST_FIRST((head1)) = LIST_FIRST((head2)); \
611
LIST_FIRST((head2)) = swap_tmp; \
612
if ((swap_tmp = LIST_FIRST((head1))) != NULL) \
613
swap_tmp->field.le_prev = &LIST_FIRST((head1)); \
614
if ((swap_tmp = LIST_FIRST((head2))) != NULL) \
615
swap_tmp->field.le_prev = &LIST_FIRST((head2)); \
616
} while (0)
617
618
#define LIST_END(head) NULL
619
620
/*
621
* Tail queue declarations.
622
*/
623
#define TAILQ_HEAD(name, type) \
624
struct name { \
625
struct type *tqh_first;
/* first element */
\
626
struct type **tqh_last;
/* addr of last next element */
\
627
TRACEBUF \
628
}
629
630
#define TAILQ_CLASS_HEAD(name, type) \
631
struct name { \
632
class type *tqh_first;
/* first element */
\
633
class type **tqh_last;
/* addr of last next element */
\
634
TRACEBUF \
635
}
636
637
#define TAILQ_HEAD_INITIALIZER(head) \
638
{ NULL, &(head).tqh_first, TRACEBUF_INITIALIZER }
639
640
#define TAILQ_ENTRY(type) \
641
struct { \
642
struct type *tqe_next;
/* next element */
\
643
struct type **tqe_prev;
/* address of previous next element */
\
644
TRACEBUF \
645
}
646
647
#define TAILQ_CLASS_ENTRY(type) \
648
struct { \
649
class type *tqe_next;
/* next element */
\
650
class type **tqe_prev;
/* address of previous next element */
\
651
TRACEBUF \
652
}
653
654
/*
655
* Tail queue functions.
656
*/
657
#if (defined(_KERNEL) && defined(INVARIANTS))
658
/*
659
* QMD_TAILQ_CHECK_HEAD(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
660
*
661
* If the tailq is non-empty, validates that the first element of the tailq
662
* points back at 'head.'
663
*/
664
#define QMD_TAILQ_CHECK_HEAD(head, field) do { \
665
if (!TAILQ_EMPTY(head) && \
666
TAILQ_FIRST((head))->field.tqe_prev != \
667
&TAILQ_FIRST((head))) \
668
panic("Bad tailq head %p first->prev != head"
, (head)); \
669
} while (0)
670
671
/*
672
* QMD_TAILQ_CHECK_TAIL(TAILQ_HEAD *head, TAILQ_ENTRY NAME)
673
*
674
* Validates that the tail of the tailq is a pointer to pointer to NULL.
675
*/
676
#define QMD_TAILQ_CHECK_TAIL(head, field) do { \
677
if (*(head)->tqh_last != NULL) \
678
panic("Bad tailq NEXT(%p->tqh_last) != NULL"
, (head)); \
679
} while (0)
680
681
/*
682
* QMD_TAILQ_CHECK_NEXT(TYPE *elm, TAILQ_ENTRY NAME)
683
*
684
* If an element follows 'elm' in the tailq, validates that the next element
685
* points back at 'elm.'
686
*/
687
#define QMD_TAILQ_CHECK_NEXT(elm, field) do { \
688
if (TAILQ_NEXT((elm), field) != NULL && \
689
TAILQ_NEXT((elm), field)->field.tqe_prev != \
690
&((elm)->field.tqe_next)) \
691
panic("Bad link elm %p next->prev != elm"
, (elm)); \
692
} while (0)
693
694
/*
695
* QMD_TAILQ_CHECK_PREV(TYPE *elm, TAILQ_ENTRY NAME)
696
*
697
* Validates that the previous element (or head of the tailq) points to 'elm.'
698
*/
699
#define QMD_TAILQ_CHECK_PREV(elm, field) do { \
700
if (*(elm)->field.tqe_prev != (elm)) \
701
panic("Bad link elm %p prev->next != elm"
, (elm)); \
702
} while (0)
703
#else
704
#define QMD_TAILQ_CHECK_HEAD(head, field)
705
#define QMD_TAILQ_CHECK_TAIL(head, headname)
706
#define QMD_TAILQ_CHECK_NEXT(elm, field)
707
#define QMD_TAILQ_CHECK_PREV(elm, field)
708
#endif
/* (_KERNEL && INVARIANTS) */
709
710
#define TAILQ_CONCAT(head1, head2, field) do { \
711
if (!TAILQ_EMPTY(head2)) { \
712
*(head1)->tqh_last = (head2)->tqh_first; \
713
(head2)->tqh_first->field.tqe_prev = (head1)->tqh_last; \
714
(head1)->tqh_last = (head2)->tqh_last; \
715
TAILQ_INIT((head2)); \
716
QMD_TRACE_HEAD(head1); \
717
QMD_TRACE_HEAD(head2); \
718
} \
719
} while (0)
720
721
#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
722
723
#define TAILQ_FIRST(head) ((head)->tqh_first)
724
725
#define TAILQ_FOREACH(var, head, field) \
726
for ((var) = TAILQ_FIRST((head)); \
727
(var); \
728
(var) = TAILQ_NEXT((var), field))
729
730
#define TAILQ_FOREACH_FROM(var, head, field) \
731
for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
732
(var); \
733
(var) = TAILQ_NEXT((var), field))
734
735
#define TAILQ_FOREACH_SAFE(var, head, field, tvar) \
736
for ((var) = TAILQ_FIRST((head)); \
737
(var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
738
(var) = (tvar))
739
740
#define TAILQ_FOREACH_FROM_SAFE(var, head, field, tvar) \
741
for ((var) = ((var) ? (var) : TAILQ_FIRST((head))); \
742
(var) && ((tvar) = TAILQ_NEXT((var), field), 1); \
743
(var) = (tvar))
744
745
#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
746
for ((var) = TAILQ_LAST((head), headname); \
747
(var); \
748
(var) = TAILQ_PREV((var), headname, field))
749
750
#define TAILQ_FOREACH_REVERSE_FROM(var, head, headname, field) \
751
for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
752
(var); \
753
(var) = TAILQ_PREV((var), headname, field))
754
755
#define TAILQ_FOREACH_REVERSE_SAFE(var, head, headname, field, tvar) \
756
for ((var) = TAILQ_LAST((head), headname); \
757
(var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
758
(var) = (tvar))
759
760
#define TAILQ_FOREACH_REVERSE_FROM_SAFE(var, head, headname, field, tvar) \
761
for ((var) = ((var) ? (var) : TAILQ_LAST((head), headname)); \
762
(var) && ((tvar) = TAILQ_PREV((var), headname, field), 1); \
763
(var) = (tvar))
764
765
#define TAILQ_INIT(head) do { \
766
TAILQ_FIRST((head)) = NULL; \
767
(head)->tqh_last = &TAILQ_FIRST((head)); \
768
QMD_TRACE_HEAD(head); \
769
} while (0)
770
771
#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
772
QMD_TAILQ_CHECK_NEXT(listelm, field); \
773
if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
774
TAILQ_NEXT((elm), field)->field.tqe_prev = \
775
&TAILQ_NEXT((elm), field); \
776
else { \
777
(head)->tqh_last = &TAILQ_NEXT((elm), field); \
778
QMD_TRACE_HEAD(head); \
779
} \
780
TAILQ_NEXT((listelm), field) = (elm); \
781
(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
782
QMD_TRACE_ELEM(&(elm)->field); \
783
QMD_TRACE_ELEM(&(listelm)->field); \
784
} while (0)
785
786
#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
787
QMD_TAILQ_CHECK_PREV(listelm, field); \
788
(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
789
TAILQ_NEXT((elm), field) = (listelm); \
790
*(listelm)->field.tqe_prev = (elm); \
791
(listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
792
QMD_TRACE_ELEM(&(elm)->field); \
793
QMD_TRACE_ELEM(&(listelm)->field); \
794
} while (0)
795
796
#define TAILQ_INSERT_HEAD(head, elm, field) do { \
797
QMD_TAILQ_CHECK_HEAD(head, field); \
798
if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
799
TAILQ_FIRST((head))->field.tqe_prev = \
800
&TAILQ_NEXT((elm), field); \
801
else \
802
(head)->tqh_last = &TAILQ_NEXT((elm), field); \
803
TAILQ_FIRST((head)) = (elm); \
804
(elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
805
QMD_TRACE_HEAD(head); \
806
QMD_TRACE_ELEM(&(elm)->field); \
807
} while (0)
808
809
#define TAILQ_INSERT_TAIL(head, elm, field) do { \
810
QMD_TAILQ_CHECK_TAIL(head, field); \
811
TAILQ_NEXT((elm), field) = NULL; \
812
(elm)->field.tqe_prev = (head)->tqh_last; \
813
*(head)->tqh_last = (elm); \
814
(head)->tqh_last = &TAILQ_NEXT((elm), field); \
815
QMD_TRACE_HEAD(head); \
816
QMD_TRACE_ELEM(&(elm)->field); \
817
} while (0)
818
819
#define TAILQ_LAST(head, headname) \
820
(*(((struct headname *)((head)->tqh_last))->tqh_last))
821
822
/*
823
* The FAST function is fast in that it causes no data access other
824
* then the access to the head. The standard LAST function above
825
* will cause a data access of both the element you want and
826
* the previous element. FAST is very useful for instances when
827
* you may want to prefetch the last data element.
828
*/
829
#define TAILQ_LAST_FAST(head, type, field) \
830
(TAILQ_EMPTY(head) ? NULL : __containerof((head)->tqh_last, QUEUE_TYPEOF(type), field.tqe_next))
831
832
#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
833
834
#define TAILQ_PREV(elm, headname, field) \
835
(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
836
837
#define TAILQ_PREV_FAST(elm, head, type, field) \
838
((elm)->field.tqe_prev == &(head)->tqh_first ? NULL : \
839
__containerof((elm)->field.tqe_prev, QUEUE_TYPEOF(type), field.tqe_next))
840
841
#define TAILQ_REMOVE(head, elm, field) do { \
842
QMD_SAVELINK(oldnext, (elm)->field.tqe_next); \
843
QMD_SAVELINK(oldprev, (elm)->field.tqe_prev); \
844
QMD_TAILQ_CHECK_NEXT(elm, field); \
845
QMD_TAILQ_CHECK_PREV(elm, field); \
846
if ((TAILQ_NEXT((elm), field)) != NULL) \
847
TAILQ_NEXT((elm), field)->field.tqe_prev = \
848
(elm)->field.tqe_prev; \
849
else { \
850
(head)->tqh_last = (elm)->field.tqe_prev; \
851
QMD_TRACE_HEAD(head); \
852
} \
853
*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
854
TRASHIT(*oldnext); \
855
TRASHIT(*oldprev); \
856
QMD_TRACE_ELEM(&(elm)->field); \
857
} while (0)
858
859
#define TAILQ_SWAP(head1, head2, type, field) do { \
860
QUEUE_TYPEOF(type) *swap_first = (head1)->tqh_first; \
861
QUEUE_TYPEOF(type) **swap_last = (head1)->tqh_last; \
862
(head1)->tqh_first = (head2)->tqh_first; \
863
(head1)->tqh_last = (head2)->tqh_last; \
864
(head2)->tqh_first = swap_first; \
865
(head2)->tqh_last = swap_last; \
866
if ((swap_first = (head1)->tqh_first) != NULL) \
867
swap_first->field.tqe_prev = &(head1)->tqh_first; \
868
else \
869
(head1)->tqh_last = &(head1)->tqh_first; \
870
if ((swap_first = (head2)->tqh_first) != NULL) \
871
swap_first->field.tqe_prev = &(head2)->tqh_first; \
872
else \
873
(head2)->tqh_last = &(head2)->tqh_first; \
874
} while (0)
875
876
#define TAILQ_END(head) NULL
877
878
#endif
/* !_SYS_QUEUE_H_ */
