xref: /openbmc/linux/drivers/scsi/aic7xxx/queue.h (revision e594a178)
1 /*
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
27  * $FreeBSD: src/sys/sys/queue.h,v 1.38 2000/05/26 02:06:56 jake Exp $
28  */
29 
30 #ifndef _SYS_QUEUE_H_
31 #define	_SYS_QUEUE_H_
32 
33 /*
34  * This file defines five types of data structures: singly-linked lists,
35  * singly-linked tail queues, lists, tail queues, and circular queues.
36  *
37  * A singly-linked list is headed by a single forward pointer. The elements
38  * are singly linked for minimum space and pointer manipulation overhead at
39  * the expense of O(n) removal for arbitrary elements. New elements can be
40  * added to the list after an existing element or at the head of the list.
41  * Elements being removed from the head of the list should use the explicit
42  * macro for this purpose for optimum efficiency. A singly-linked list may
43  * only be traversed in the forward direction.  Singly-linked lists are ideal
44  * for applications with large datasets and few or no removals or for
45  * implementing a LIFO queue.
46  *
47  * A singly-linked tail queue is headed by a pair of pointers, one to the
48  * head of the list and the other to the tail of the list. The elements are
49  * singly linked for minimum space and pointer manipulation overhead at the
50  * expense of O(n) removal for arbitrary elements. New elements can be added
51  * to the list after an existing element, at the head of the list, or at the
52  * end of the list. Elements being removed from the head of the tail queue
53  * should use the explicit macro for this purpose for optimum efficiency.
54  * A singly-linked tail queue may only be traversed in the forward direction.
55  * Singly-linked tail queues are ideal for applications with large datasets
56  * and few or no removals or for implementing a FIFO queue.
57  *
58  * A list is headed by a single forward pointer (or an array of forward
59  * pointers for a hash table header). The elements are doubly linked
60  * so that an arbitrary element can be removed without a need to
61  * traverse the list. New elements can be added to the list before
62  * or after an existing element or at the head of the list. A list
63  * may only be traversed in the forward direction.
64  *
65  * A tail queue is headed by a pair of pointers, one to the head of the
66  * list and the other to the tail of the list. The elements are doubly
67  * linked so that an arbitrary element can be removed without a need to
68  * traverse the list. New elements can be added to the list before or
69  * after an existing element, at the head of the list, or at the end of
70  * the list. A tail queue may be traversed in either direction.
71  *
72  * A circle queue is headed by a pair of pointers, one to the head of the
73  * list and the other to the tail of the list. The elements are doubly
74  * linked so that an arbitrary element can be removed without a need to
75  * traverse the list. New elements can be added to the list before or after
76  * an existing element, at the head of the list, or at the end of the list.
77  * A circle queue may be traversed in either direction, but has a more
78  * complex end of list detection.
79  *
80  * For details on the use of these macros, see the queue(3) manual page.
81  *
82  *
83  *			SLIST	LIST	STAILQ	TAILQ	CIRCLEQ
84  * _HEAD		+	+	+	+	+
85  * _HEAD_INITIALIZER	+	+	+	+	+
86  * _ENTRY		+	+	+	+	+
87  * _INIT		+	+	+	+	+
88  * _EMPTY		+	+	+	+	+
89  * _FIRST		+	+	+	+	+
90  * _NEXT		+	+	+	+	+
91  * _PREV		-	-	-	+	+
92  * _LAST		-	-	+	+	+
93  * _FOREACH		+	+	+	+	+
94  * _FOREACH_REVERSE	-	-	-	+	+
95  * _INSERT_HEAD		+	+	+	+	+
96  * _INSERT_BEFORE	-	+	-	+	+
97  * _INSERT_AFTER	+	+	+	+	+
98  * _INSERT_TAIL		-	-	+	+	+
99  * _REMOVE_HEAD		+	-	+	-	-
100  * _REMOVE		+	+	+	+	+
101  *
102  */
103 
104 /*
105  * Singly-linked List declarations.
106  */
107 #define	SLIST_HEAD(name, type)						\
108 struct name {								\
109 	struct type *slh_first;	/* first element */			\
110 }
111 
112 #define	SLIST_HEAD_INITIALIZER(head)					\
113 	{ NULL }
114 
115 #define	SLIST_ENTRY(type)						\
116 struct {								\
117 	struct type *sle_next;	/* next element */			\
118 }
119 
120 /*
121  * Singly-linked List functions.
122  */
123 #define	SLIST_EMPTY(head)	((head)->slh_first == NULL)
124 
125 #define	SLIST_FIRST(head)	((head)->slh_first)
126 
127 #define	SLIST_FOREACH(var, head, field)					\
128 	for ((var) = SLIST_FIRST((head));				\
129 	    (var);							\
130 	    (var) = SLIST_NEXT((var), field))
131 
132 #define	SLIST_INIT(head) do {						\
133 	SLIST_FIRST((head)) = NULL;					\
134 } while (0)
135 
136 #define	SLIST_INSERT_AFTER(slistelm, elm, field) do {			\
137 	SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field);	\
138 	SLIST_NEXT((slistelm), field) = (elm);				\
139 } while (0)
140 
141 #define	SLIST_INSERT_HEAD(head, elm, field) do {			\
142 	SLIST_NEXT((elm), field) = SLIST_FIRST((head));			\
143 	SLIST_FIRST((head)) = (elm);					\
144 } while (0)
145 
146 #define	SLIST_NEXT(elm, field)	((elm)->field.sle_next)
147 
148 #define	SLIST_REMOVE(head, elm, type, field) do {			\
149 	if (SLIST_FIRST((head)) == (elm)) {				\
150 		SLIST_REMOVE_HEAD((head), field);			\
151 	}								\
152 	else {								\
153 		struct type *curelm = SLIST_FIRST((head));		\
154 		while (SLIST_NEXT(curelm, field) != (elm))		\
155 			curelm = SLIST_NEXT(curelm, field);		\
156 		SLIST_NEXT(curelm, field) =				\
157 		    SLIST_NEXT(SLIST_NEXT(curelm, field), field);	\
158 	}								\
159 } while (0)
160 
161 #define	SLIST_REMOVE_HEAD(head, field) do {				\
162 	SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field);	\
163 } while (0)
164 
165 /*
166  * Singly-linked Tail queue declarations.
167  */
168 #define	STAILQ_HEAD(name, type)						\
169 struct name {								\
170 	struct type *stqh_first;/* first element */			\
171 	struct type **stqh_last;/* addr of last next element */		\
172 }
173 
174 #define	STAILQ_HEAD_INITIALIZER(head)					\
175 	{ NULL, &(head).stqh_first }
176 
177 #define	STAILQ_ENTRY(type)						\
178 struct {								\
179 	struct type *stqe_next;	/* next element */			\
180 }
181 
182 /*
183  * Singly-linked Tail queue functions.
184  */
185 #define	STAILQ_EMPTY(head)	((head)->stqh_first == NULL)
186 
187 #define	STAILQ_FIRST(head)	((head)->stqh_first)
188 
189 #define	STAILQ_FOREACH(var, head, field)				\
190 	for((var) = STAILQ_FIRST((head));				\
191 	   (var);							\
192 	   (var) = STAILQ_NEXT((var), field))
193 
194 #define	STAILQ_INIT(head) do {						\
195 	STAILQ_FIRST((head)) = NULL;					\
196 	(head)->stqh_last = &STAILQ_FIRST((head));			\
197 } while (0)
198 
199 #define	STAILQ_INSERT_AFTER(head, tqelm, elm, field) do {		\
200 	if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
201 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
202 	STAILQ_NEXT((tqelm), field) = (elm);				\
203 } while (0)
204 
205 #define	STAILQ_INSERT_HEAD(head, elm, field) do {			\
206 	if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL)	\
207 		(head)->stqh_last = &STAILQ_NEXT((elm), field);		\
208 	STAILQ_FIRST((head)) = (elm);					\
209 } while (0)
210 
211 #define	STAILQ_INSERT_TAIL(head, elm, field) do {			\
212 	STAILQ_NEXT((elm), field) = NULL;				\
213 	STAILQ_LAST((head)) = (elm);					\
214 	(head)->stqh_last = &STAILQ_NEXT((elm), field);			\
215 } while (0)
216 
217 #define	STAILQ_LAST(head)	(*(head)->stqh_last)
218 
219 #define	STAILQ_NEXT(elm, field)	((elm)->field.stqe_next)
220 
221 #define	STAILQ_REMOVE(head, elm, type, field) do {			\
222 	if (STAILQ_FIRST((head)) == (elm)) {				\
223 		STAILQ_REMOVE_HEAD(head, field);			\
224 	}								\
225 	else {								\
226 		struct type *curelm = STAILQ_FIRST((head));		\
227 		while (STAILQ_NEXT(curelm, field) != (elm))		\
228 			curelm = STAILQ_NEXT(curelm, field);		\
229 		if ((STAILQ_NEXT(curelm, field) =			\
230 		     STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
231 			(head)->stqh_last = &STAILQ_NEXT((curelm), field);\
232 	}								\
233 } while (0)
234 
235 #define	STAILQ_REMOVE_HEAD(head, field) do {				\
236 	if ((STAILQ_FIRST((head)) =					\
237 	     STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL)		\
238 		(head)->stqh_last = &STAILQ_FIRST((head));		\
239 } while (0)
240 
241 #define	STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do {			\
242 	if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL)	\
243 		(head)->stqh_last = &STAILQ_FIRST((head));		\
244 } while (0)
245 
246 /*
247  * List declarations.
248  */
249 #define	BSD_LIST_HEAD(name, type)					\
250 struct name {								\
251 	struct type *lh_first;	/* first element */			\
252 }
253 
254 #define	LIST_HEAD_INITIALIZER(head)					\
255 	{ NULL }
256 
257 #define	LIST_ENTRY(type)						\
258 struct {								\
259 	struct type *le_next;	/* next element */			\
260 	struct type **le_prev;	/* address of previous next element */	\
261 }
262 
263 /*
264  * List functions.
265  */
266 
267 #define	LIST_EMPTY(head)	((head)->lh_first == NULL)
268 
269 #define	LIST_FIRST(head)	((head)->lh_first)
270 
271 #define	LIST_FOREACH(var, head, field)					\
272 	for ((var) = LIST_FIRST((head));				\
273 	    (var);							\
274 	    (var) = LIST_NEXT((var), field))
275 
276 #define	LIST_INIT(head) do {						\
277 	LIST_FIRST((head)) = NULL;					\
278 } while (0)
279 
280 #define	LIST_INSERT_AFTER(listelm, elm, field) do {			\
281 	if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
282 		LIST_NEXT((listelm), field)->field.le_prev =		\
283 		    &LIST_NEXT((elm), field);				\
284 	LIST_NEXT((listelm), field) = (elm);				\
285 	(elm)->field.le_prev = &LIST_NEXT((listelm), field);		\
286 } while (0)
287 
288 #define	LIST_INSERT_BEFORE(listelm, elm, field) do {			\
289 	(elm)->field.le_prev = (listelm)->field.le_prev;		\
290 	LIST_NEXT((elm), field) = (listelm);				\
291 	*(listelm)->field.le_prev = (elm);				\
292 	(listelm)->field.le_prev = &LIST_NEXT((elm), field);		\
293 } while (0)
294 
295 #define	LIST_INSERT_HEAD(head, elm, field) do {				\
296 	if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL)	\
297 		LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
298 	LIST_FIRST((head)) = (elm);					\
299 	(elm)->field.le_prev = &LIST_FIRST((head));			\
300 } while (0)
301 
302 #define	LIST_NEXT(elm, field)	((elm)->field.le_next)
303 
304 #define	LIST_REMOVE(elm, field) do {					\
305 	if (LIST_NEXT((elm), field) != NULL)				\
306 		LIST_NEXT((elm), field)->field.le_prev = 		\
307 		    (elm)->field.le_prev;				\
308 	*(elm)->field.le_prev = LIST_NEXT((elm), field);		\
309 } while (0)
310 
311 /*
312  * Tail queue declarations.
313  */
314 #define	TAILQ_HEAD(name, type)						\
315 struct name {								\
316 	struct type *tqh_first;	/* first element */			\
317 	struct type **tqh_last;	/* addr of last next element */		\
318 }
319 
320 #define	TAILQ_HEAD_INITIALIZER(head)					\
321 	{ NULL, &(head).tqh_first }
322 
323 #define	TAILQ_ENTRY(type)						\
324 struct {								\
325 	struct type *tqe_next;	/* next element */			\
326 	struct type **tqe_prev;	/* address of previous next element */	\
327 }
328 
329 /*
330  * Tail queue functions.
331  */
332 #define	TAILQ_EMPTY(head)	((head)->tqh_first == NULL)
333 
334 #define	TAILQ_FIRST(head)	((head)->tqh_first)
335 
336 #define	TAILQ_FOREACH(var, head, field)					\
337 	for ((var) = TAILQ_FIRST((head));				\
338 	    (var);							\
339 	    (var) = TAILQ_NEXT((var), field))
340 
341 #define	TAILQ_FOREACH_REVERSE(var, head, headname, field)		\
342 	for ((var) = TAILQ_LAST((head), headname);			\
343 	    (var);							\
344 	    (var) = TAILQ_PREV((var), headname, field))
345 
346 #define	TAILQ_INIT(head) do {						\
347 	TAILQ_FIRST((head)) = NULL;					\
348 	(head)->tqh_last = &TAILQ_FIRST((head));			\
349 } while (0)
350 
351 #define	TAILQ_INSERT_AFTER(head, listelm, elm, field) do {		\
352 	if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
353 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
354 		    &TAILQ_NEXT((elm), field);				\
355 	else								\
356 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
357 	TAILQ_NEXT((listelm), field) = (elm);				\
358 	(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field);		\
359 } while (0)
360 
361 #define	TAILQ_INSERT_BEFORE(listelm, elm, field) do {			\
362 	(elm)->field.tqe_prev = (listelm)->field.tqe_prev;		\
363 	TAILQ_NEXT((elm), field) = (listelm);				\
364 	*(listelm)->field.tqe_prev = (elm);				\
365 	(listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field);		\
366 } while (0)
367 
368 #define	TAILQ_INSERT_HEAD(head, elm, field) do {			\
369 	if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL)	\
370 		TAILQ_FIRST((head))->field.tqe_prev =			\
371 		    &TAILQ_NEXT((elm), field);				\
372 	else								\
373 		(head)->tqh_last = &TAILQ_NEXT((elm), field);		\
374 	TAILQ_FIRST((head)) = (elm);					\
375 	(elm)->field.tqe_prev = &TAILQ_FIRST((head));			\
376 } while (0)
377 
378 #define	TAILQ_INSERT_TAIL(head, elm, field) do {			\
379 	TAILQ_NEXT((elm), field) = NULL;				\
380 	(elm)->field.tqe_prev = (head)->tqh_last;			\
381 	*(head)->tqh_last = (elm);					\
382 	(head)->tqh_last = &TAILQ_NEXT((elm), field);			\
383 } while (0)
384 
385 #define	TAILQ_LAST(head, headname)					\
386 	(*(((struct headname *)((head)->tqh_last))->tqh_last))
387 
388 #define	TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
389 
390 #define	TAILQ_PREV(elm, headname, field)				\
391 	(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
392 
393 #define	TAILQ_REMOVE(head, elm, field) do {				\
394 	if ((TAILQ_NEXT((elm), field)) != NULL)				\
395 		TAILQ_NEXT((elm), field)->field.tqe_prev = 		\
396 		    (elm)->field.tqe_prev;				\
397 	else								\
398 		(head)->tqh_last = (elm)->field.tqe_prev;		\
399 	*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field);		\
400 } while (0)
401 
402 /*
403  * Circular queue declarations.
404  */
405 #define	CIRCLEQ_HEAD(name, type)					\
406 struct name {								\
407 	struct type *cqh_first;		/* first element */		\
408 	struct type *cqh_last;		/* last element */		\
409 }
410 
411 #define	CIRCLEQ_HEAD_INITIALIZER(head)					\
412 	{ (void *)&(head), (void *)&(head) }
413 
414 #define	CIRCLEQ_ENTRY(type)						\
415 struct {								\
416 	struct type *cqe_next;		/* next element */		\
417 	struct type *cqe_prev;		/* previous element */		\
418 }
419 
420 /*
421  * Circular queue functions.
422  */
423 #define	CIRCLEQ_EMPTY(head)	((head)->cqh_first == (void *)(head))
424 
425 #define	CIRCLEQ_FIRST(head)	((head)->cqh_first)
426 
427 #define	CIRCLEQ_FOREACH(var, head, field)				\
428 	for ((var) = CIRCLEQ_FIRST((head));				\
429 	    (var) != (void *)(head);					\
430 	    (var) = CIRCLEQ_NEXT((var), field))
431 
432 #define	CIRCLEQ_FOREACH_REVERSE(var, head, field)			\
433 	for ((var) = CIRCLEQ_LAST((head));				\
434 	    (var) != (void *)(head);					\
435 	    (var) = CIRCLEQ_PREV((var), field))
436 
437 #define	CIRCLEQ_INIT(head) do {						\
438 	CIRCLEQ_FIRST((head)) = (void *)(head);				\
439 	CIRCLEQ_LAST((head)) = (void *)(head);				\
440 } while (0)
441 
442 #define	CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do {		\
443 	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_NEXT((listelm), field);	\
444 	CIRCLEQ_PREV((elm), field) = (listelm);				\
445 	if (CIRCLEQ_NEXT((listelm), field) == (void *)(head))		\
446 		CIRCLEQ_LAST((head)) = (elm);				\
447 	else								\
448 		CIRCLEQ_PREV(CIRCLEQ_NEXT((listelm), field), field) = (elm);\
449 	CIRCLEQ_NEXT((listelm), field) = (elm);				\
450 } while (0)
451 
452 #define	CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do {		\
453 	CIRCLEQ_NEXT((elm), field) = (listelm);				\
454 	CIRCLEQ_PREV((elm), field) = CIRCLEQ_PREV((listelm), field);	\
455 	if (CIRCLEQ_PREV((listelm), field) == (void *)(head))		\
456 		CIRCLEQ_FIRST((head)) = (elm);				\
457 	else								\
458 		CIRCLEQ_NEXT(CIRCLEQ_PREV((listelm), field), field) = (elm);\
459 	CIRCLEQ_PREV((listelm), field) = (elm);				\
460 } while (0)
461 
462 #define	CIRCLEQ_INSERT_HEAD(head, elm, field) do {			\
463 	CIRCLEQ_NEXT((elm), field) = CIRCLEQ_FIRST((head));		\
464 	CIRCLEQ_PREV((elm), field) = (void *)(head);			\
465 	if (CIRCLEQ_LAST((head)) == (void *)(head))			\
466 		CIRCLEQ_LAST((head)) = (elm);				\
467 	else								\
468 		CIRCLEQ_PREV(CIRCLEQ_FIRST((head)), field) = (elm);	\
469 	CIRCLEQ_FIRST((head)) = (elm);					\
470 } while (0)
471 
472 #define	CIRCLEQ_INSERT_TAIL(head, elm, field) do {			\
473 	CIRCLEQ_NEXT((elm), field) = (void *)(head);			\
474 	CIRCLEQ_PREV((elm), field) = CIRCLEQ_LAST((head));		\
475 	if (CIRCLEQ_FIRST((head)) == (void *)(head))			\
476 		CIRCLEQ_FIRST((head)) = (elm);				\
477 	else								\
478 		CIRCLEQ_NEXT(CIRCLEQ_LAST((head)), field) = (elm);	\
479 	CIRCLEQ_LAST((head)) = (elm);					\
480 } while (0)
481 
482 #define	CIRCLEQ_LAST(head)	((head)->cqh_last)
483 
484 #define	CIRCLEQ_NEXT(elm,field)	((elm)->field.cqe_next)
485 
486 #define	CIRCLEQ_PREV(elm,field)	((elm)->field.cqe_prev)
487 
488 #define	CIRCLEQ_REMOVE(head, elm, field) do {				\
489 	if (CIRCLEQ_NEXT((elm), field) == (void *)(head))		\
490 		CIRCLEQ_LAST((head)) = CIRCLEQ_PREV((elm), field);	\
491 	else								\
492 		CIRCLEQ_PREV(CIRCLEQ_NEXT((elm), field), field) =	\
493 		    CIRCLEQ_PREV((elm), field);				\
494 	if (CIRCLEQ_PREV((elm), field) == (void *)(head))		\
495 		CIRCLEQ_FIRST((head)) = CIRCLEQ_NEXT((elm), field);	\
496 	else								\
497 		CIRCLEQ_NEXT(CIRCLEQ_PREV((elm), field), field) =	\
498 		    CIRCLEQ_NEXT((elm), field);				\
499 } while (0)
500 
501 #endif /* !_SYS_QUEUE_H_ */
502