xref: /freebsd/sys/contrib/openzfs/lib/libuutil/uu_avl.c (revision b197d4b893974c9eb4d7b38704c6d5c486235d6f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 
27 
28 #include "libuutil_common.h"
29 
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <sys/avl.h>
34 
35 static uu_avl_pool_t	uu_null_apool = { &uu_null_apool, &uu_null_apool };
36 static pthread_mutex_t	uu_apool_list_lock = PTHREAD_MUTEX_INITIALIZER;
37 
38 /*
39  * The index mark change on every insert and delete, to catch stale
40  * references.
41  *
42  * We leave the low bit alone, since the avl code uses it.
43  */
44 #define	INDEX_MAX		(sizeof (uintptr_t) - 2)
45 #define	INDEX_NEXT(m)		(((m) == INDEX_MAX)? 2 : ((m) + 2) & INDEX_MAX)
46 
47 #define	INDEX_DECODE(i)		((i) & ~INDEX_MAX)
48 #define	INDEX_ENCODE(p, n)	(((n) & ~INDEX_MAX) | (p)->ua_index)
49 #define	INDEX_VALID(p, i)	(((i) & INDEX_MAX) == (p)->ua_index)
50 #define	INDEX_CHECK(i)		(((i) & INDEX_MAX) != 0)
51 
52 /*
53  * When an element is inactive (not in a tree), we keep a marked pointer to
54  * its containing pool in its first word, and a NULL pointer in its second.
55  *
56  * On insert, we use these to verify that it comes from the correct pool.
57  */
58 #define	NODE_ARRAY(p, n)	((uintptr_t *)((uintptr_t)(n) + \
59 				    (pp)->uap_nodeoffset))
60 
61 #define	POOL_TO_MARKER(pp) (((uintptr_t)(pp) | 1))
62 
63 #define	DEAD_MARKER		0xc4
64 
65 uu_avl_pool_t *
66 uu_avl_pool_create(const char *name, size_t objsize, size_t nodeoffset,
67     uu_compare_fn_t *compare_func, uint32_t flags)
68 {
69 	uu_avl_pool_t *pp, *next, *prev;
70 
71 	if (name == NULL ||
72 	    uu_check_name(name, UU_NAME_DOMAIN) == -1 ||
73 	    nodeoffset + sizeof (uu_avl_node_t) > objsize ||
74 	    compare_func == NULL) {
75 		uu_set_error(UU_ERROR_INVALID_ARGUMENT);
76 		return (NULL);
77 	}
78 
79 	if (flags & ~UU_AVL_POOL_DEBUG) {
80 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
81 		return (NULL);
82 	}
83 
84 	pp = uu_zalloc(sizeof (uu_avl_pool_t));
85 	if (pp == NULL) {
86 		uu_set_error(UU_ERROR_NO_MEMORY);
87 		return (NULL);
88 	}
89 
90 	(void) strlcpy(pp->uap_name, name, sizeof (pp->uap_name));
91 	pp->uap_nodeoffset = nodeoffset;
92 	pp->uap_objsize = objsize;
93 	pp->uap_cmp = compare_func;
94 	if (flags & UU_AVL_POOL_DEBUG)
95 		pp->uap_debug = 1;
96 	pp->uap_last_index = 0;
97 
98 	(void) pthread_mutex_init(&pp->uap_lock, NULL);
99 
100 	pp->uap_null_avl.ua_next_enc = UU_PTR_ENCODE(&pp->uap_null_avl);
101 	pp->uap_null_avl.ua_prev_enc = UU_PTR_ENCODE(&pp->uap_null_avl);
102 
103 	(void) pthread_mutex_lock(&uu_apool_list_lock);
104 	pp->uap_next = next = &uu_null_apool;
105 	pp->uap_prev = prev = next->uap_prev;
106 	next->uap_prev = pp;
107 	prev->uap_next = pp;
108 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
109 
110 	return (pp);
111 }
112 
113 void
114 uu_avl_pool_destroy(uu_avl_pool_t *pp)
115 {
116 	if (pp->uap_debug) {
117 		if (pp->uap_null_avl.ua_next_enc !=
118 		    UU_PTR_ENCODE(&pp->uap_null_avl) ||
119 		    pp->uap_null_avl.ua_prev_enc !=
120 		    UU_PTR_ENCODE(&pp->uap_null_avl)) {
121 			uu_panic("uu_avl_pool_destroy: Pool \"%.*s\" (%p) has "
122 			    "outstanding avls, or is corrupt.\n",
123 			    (int)sizeof (pp->uap_name), pp->uap_name,
124 			    (void *)pp);
125 		}
126 	}
127 	(void) pthread_mutex_lock(&uu_apool_list_lock);
128 	pp->uap_next->uap_prev = pp->uap_prev;
129 	pp->uap_prev->uap_next = pp->uap_next;
130 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
131 	(void) pthread_mutex_destroy(&pp->uap_lock);
132 	pp->uap_prev = NULL;
133 	pp->uap_next = NULL;
134 	uu_free(pp);
135 }
136 
137 void
138 uu_avl_node_init(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
139 {
140 	uintptr_t *na = (uintptr_t *)np;
141 
142 	if (pp->uap_debug) {
143 		uintptr_t offset = (uintptr_t)np - (uintptr_t)base;
144 		if (offset + sizeof (*np) > pp->uap_objsize) {
145 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
146 			    "offset %ld doesn't fit in object (size %ld)\n",
147 			    base, (void *)np, (void *)pp, pp->uap_name,
148 			    (long)offset, (long)pp->uap_objsize);
149 		}
150 		if (offset != pp->uap_nodeoffset) {
151 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
152 			    "offset %ld doesn't match pool's offset (%ld)\n",
153 			    base, (void *)np, (void *)pp, pp->uap_name,
154 			    (long)offset, (long)pp->uap_objsize);
155 		}
156 	}
157 
158 	na[0] = POOL_TO_MARKER(pp);
159 	na[1] = 0;
160 }
161 
162 void
163 uu_avl_node_fini(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
164 {
165 	uintptr_t *na = (uintptr_t *)np;
166 
167 	if (pp->uap_debug) {
168 		if (na[0] == DEAD_MARKER && na[1] == DEAD_MARKER) {
169 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
170 			    "node already finied\n",
171 			    base, (void *)np, (void *)pp, pp->uap_name);
172 		}
173 		if (na[0] != POOL_TO_MARKER(pp) || na[1] != 0) {
174 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
175 			    "node corrupt, in tree, or in different pool\n",
176 			    base, (void *)np, (void *)pp, pp->uap_name);
177 		}
178 	}
179 
180 	na[0] = DEAD_MARKER;
181 	na[1] = DEAD_MARKER;
182 	na[2] = DEAD_MARKER;
183 }
184 
185 struct uu_avl_node_compare_info {
186 	uu_compare_fn_t	*ac_compare;
187 	void		*ac_private;
188 	void		*ac_right;
189 	void		*ac_found;
190 };
191 
192 static int
193 uu_avl_node_compare(const void *l, const void *r)
194 {
195 	struct uu_avl_node_compare_info *info =
196 	    (struct uu_avl_node_compare_info *)l;
197 
198 	int res = info->ac_compare(r, info->ac_right, info->ac_private);
199 
200 	if (res == 0) {
201 		if (info->ac_found == NULL)
202 			info->ac_found = (void *)r;
203 		return (-1);
204 	}
205 	if (res < 0)
206 		return (1);
207 	return (-1);
208 }
209 
210 uu_avl_t *
211 uu_avl_create(uu_avl_pool_t *pp, void *parent, uint32_t flags)
212 {
213 	uu_avl_t *ap, *next, *prev;
214 
215 	if (flags & ~UU_AVL_DEBUG) {
216 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
217 		return (NULL);
218 	}
219 
220 	ap = uu_zalloc(sizeof (*ap));
221 	if (ap == NULL) {
222 		uu_set_error(UU_ERROR_NO_MEMORY);
223 		return (NULL);
224 	}
225 
226 	ap->ua_pool = pp;
227 	ap->ua_parent_enc = UU_PTR_ENCODE(parent);
228 	ap->ua_debug = pp->uap_debug || (flags & UU_AVL_DEBUG);
229 	ap->ua_index = (pp->uap_last_index = INDEX_NEXT(pp->uap_last_index));
230 
231 	avl_create(&ap->ua_tree, &uu_avl_node_compare, pp->uap_objsize,
232 	    pp->uap_nodeoffset);
233 
234 	ap->ua_null_walk.uaw_next = &ap->ua_null_walk;
235 	ap->ua_null_walk.uaw_prev = &ap->ua_null_walk;
236 
237 	(void) pthread_mutex_lock(&pp->uap_lock);
238 	next = &pp->uap_null_avl;
239 	prev = UU_PTR_DECODE(next->ua_prev_enc);
240 	ap->ua_next_enc = UU_PTR_ENCODE(next);
241 	ap->ua_prev_enc = UU_PTR_ENCODE(prev);
242 	next->ua_prev_enc = UU_PTR_ENCODE(ap);
243 	prev->ua_next_enc = UU_PTR_ENCODE(ap);
244 	(void) pthread_mutex_unlock(&pp->uap_lock);
245 
246 	return (ap);
247 }
248 
249 void
250 uu_avl_destroy(uu_avl_t *ap)
251 {
252 	uu_avl_pool_t *pp = ap->ua_pool;
253 
254 	if (ap->ua_debug) {
255 		if (avl_numnodes(&ap->ua_tree) != 0) {
256 			uu_panic("uu_avl_destroy(%p): tree not empty\n",
257 			    (void *)ap);
258 		}
259 		if (ap->ua_null_walk.uaw_next != &ap->ua_null_walk ||
260 		    ap->ua_null_walk.uaw_prev != &ap->ua_null_walk) {
261 			uu_panic("uu_avl_destroy(%p):  outstanding walkers\n",
262 			    (void *)ap);
263 		}
264 	}
265 	(void) pthread_mutex_lock(&pp->uap_lock);
266 	UU_AVL_PTR(ap->ua_next_enc)->ua_prev_enc = ap->ua_prev_enc;
267 	UU_AVL_PTR(ap->ua_prev_enc)->ua_next_enc = ap->ua_next_enc;
268 	(void) pthread_mutex_unlock(&pp->uap_lock);
269 	ap->ua_prev_enc = UU_PTR_ENCODE(NULL);
270 	ap->ua_next_enc = UU_PTR_ENCODE(NULL);
271 
272 	ap->ua_pool = NULL;
273 	avl_destroy(&ap->ua_tree);
274 
275 	uu_free(ap);
276 }
277 
278 size_t
279 uu_avl_numnodes(uu_avl_t *ap)
280 {
281 	return (avl_numnodes(&ap->ua_tree));
282 }
283 
284 void *
285 uu_avl_first(uu_avl_t *ap)
286 {
287 	return (avl_first(&ap->ua_tree));
288 }
289 
290 void *
291 uu_avl_last(uu_avl_t *ap)
292 {
293 	return (avl_last(&ap->ua_tree));
294 }
295 
296 void *
297 uu_avl_next(uu_avl_t *ap, void *node)
298 {
299 	return (AVL_NEXT(&ap->ua_tree, node));
300 }
301 
302 void *
303 uu_avl_prev(uu_avl_t *ap, void *node)
304 {
305 	return (AVL_PREV(&ap->ua_tree, node));
306 }
307 
308 static void
309 _avl_walk_init(uu_avl_walk_t *wp, uu_avl_t *ap, uint32_t flags)
310 {
311 	uu_avl_walk_t *next, *prev;
312 
313 	int robust = (flags & UU_WALK_ROBUST);
314 	int direction = (flags & UU_WALK_REVERSE)? -1 : 1;
315 
316 	(void) memset(wp, 0, sizeof (*wp));
317 	wp->uaw_avl = ap;
318 	wp->uaw_robust = robust;
319 	wp->uaw_dir = direction;
320 
321 	if (direction > 0)
322 		wp->uaw_next_result = avl_first(&ap->ua_tree);
323 	else
324 		wp->uaw_next_result = avl_last(&ap->ua_tree);
325 
326 	if (ap->ua_debug || robust) {
327 		wp->uaw_next = next = &ap->ua_null_walk;
328 		wp->uaw_prev = prev = next->uaw_prev;
329 		next->uaw_prev = wp;
330 		prev->uaw_next = wp;
331 	}
332 }
333 
334 static void *
335 _avl_walk_advance(uu_avl_walk_t *wp, uu_avl_t *ap)
336 {
337 	void *np = wp->uaw_next_result;
338 
339 	avl_tree_t *t = &ap->ua_tree;
340 
341 	if (np == NULL)
342 		return (NULL);
343 
344 	wp->uaw_next_result = (wp->uaw_dir > 0)? AVL_NEXT(t, np) :
345 	    AVL_PREV(t, np);
346 
347 	return (np);
348 }
349 
350 static void
351 _avl_walk_fini(uu_avl_walk_t *wp)
352 {
353 	if (wp->uaw_next != NULL) {
354 		wp->uaw_next->uaw_prev = wp->uaw_prev;
355 		wp->uaw_prev->uaw_next = wp->uaw_next;
356 		wp->uaw_next = NULL;
357 		wp->uaw_prev = NULL;
358 	}
359 	wp->uaw_avl = NULL;
360 	wp->uaw_next_result = NULL;
361 }
362 
363 uu_avl_walk_t *
364 uu_avl_walk_start(uu_avl_t *ap, uint32_t flags)
365 {
366 	uu_avl_walk_t *wp;
367 
368 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
369 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
370 		return (NULL);
371 	}
372 
373 	wp = uu_zalloc(sizeof (*wp));
374 	if (wp == NULL) {
375 		uu_set_error(UU_ERROR_NO_MEMORY);
376 		return (NULL);
377 	}
378 
379 	_avl_walk_init(wp, ap, flags);
380 	return (wp);
381 }
382 
383 void *
384 uu_avl_walk_next(uu_avl_walk_t *wp)
385 {
386 	return (_avl_walk_advance(wp, wp->uaw_avl));
387 }
388 
389 void
390 uu_avl_walk_end(uu_avl_walk_t *wp)
391 {
392 	_avl_walk_fini(wp);
393 	uu_free(wp);
394 }
395 
396 int
397 uu_avl_walk(uu_avl_t *ap, uu_walk_fn_t *func, void *private, uint32_t flags)
398 {
399 	void *e;
400 	uu_avl_walk_t my_walk;
401 
402 	int status = UU_WALK_NEXT;
403 
404 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
405 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
406 		return (-1);
407 	}
408 
409 	_avl_walk_init(&my_walk, ap, flags);
410 	while (status == UU_WALK_NEXT &&
411 	    (e = _avl_walk_advance(&my_walk, ap)) != NULL)
412 		status = (*func)(e, private);
413 	_avl_walk_fini(&my_walk);
414 
415 	if (status >= 0)
416 		return (0);
417 	uu_set_error(UU_ERROR_CALLBACK_FAILED);
418 	return (-1);
419 }
420 
421 void
422 uu_avl_remove(uu_avl_t *ap, void *elem)
423 {
424 	uu_avl_walk_t *wp;
425 	uu_avl_pool_t *pp = ap->ua_pool;
426 	uintptr_t *na = NODE_ARRAY(pp, elem);
427 
428 	if (ap->ua_debug) {
429 		/*
430 		 * invalidate outstanding uu_avl_index_ts.
431 		 */
432 		ap->ua_index = INDEX_NEXT(ap->ua_index);
433 	}
434 
435 	/*
436 	 * Robust walkers most be advanced, if we are removing the node
437 	 * they are currently using.  In debug mode, non-robust walkers
438 	 * are also on the walker list.
439 	 */
440 	for (wp = ap->ua_null_walk.uaw_next; wp != &ap->ua_null_walk;
441 	    wp = wp->uaw_next) {
442 		if (wp->uaw_robust) {
443 			if (elem == wp->uaw_next_result)
444 				(void) _avl_walk_advance(wp, ap);
445 		} else if (wp->uaw_next_result != NULL) {
446 			uu_panic("uu_avl_remove(%p, %p): active non-robust "
447 			    "walker\n", (void *)ap, elem);
448 		}
449 	}
450 
451 	avl_remove(&ap->ua_tree, elem);
452 
453 	na[0] = POOL_TO_MARKER(pp);
454 	na[1] = 0;
455 }
456 
457 void *
458 uu_avl_teardown(uu_avl_t *ap, void **cookie)
459 {
460 	void *elem = avl_destroy_nodes(&ap->ua_tree, cookie);
461 
462 	if (elem != NULL) {
463 		uu_avl_pool_t *pp = ap->ua_pool;
464 		uintptr_t *na = NODE_ARRAY(pp, elem);
465 
466 		na[0] = POOL_TO_MARKER(pp);
467 		na[1] = 0;
468 	}
469 	return (elem);
470 }
471 
472 void *
473 uu_avl_find(uu_avl_t *ap, void *elem, void *private, uu_avl_index_t *out)
474 {
475 	struct uu_avl_node_compare_info info;
476 	void *result;
477 
478 	info.ac_compare = ap->ua_pool->uap_cmp;
479 	info.ac_private = private;
480 	info.ac_right = elem;
481 	info.ac_found = NULL;
482 
483 	result = avl_find(&ap->ua_tree, &info, out);
484 	if (out != NULL)
485 		*out = INDEX_ENCODE(ap, *out);
486 
487 	if (ap->ua_debug && result != NULL)
488 		uu_panic("uu_avl_find: internal error: avl_find succeeded\n");
489 
490 	return (info.ac_found);
491 }
492 
493 void
494 uu_avl_insert(uu_avl_t *ap, void *elem, uu_avl_index_t idx)
495 {
496 	if (ap->ua_debug) {
497 		uu_avl_pool_t *pp = ap->ua_pool;
498 		uintptr_t *na = NODE_ARRAY(pp, elem);
499 
500 		if (na[1] != 0)
501 			uu_panic("uu_avl_insert(%p, %p, %p): node already "
502 			    "in tree, or corrupt\n",
503 			    (void *)ap, elem, (void *)idx);
504 		if (na[0] == 0)
505 			uu_panic("uu_avl_insert(%p, %p, %p): node not "
506 			    "initialized\n",
507 			    (void *)ap, elem, (void *)idx);
508 		if (na[0] != POOL_TO_MARKER(pp))
509 			uu_panic("uu_avl_insert(%p, %p, %p): node from "
510 			    "other pool, or corrupt\n",
511 			    (void *)ap, elem, (void *)idx);
512 
513 		if (!INDEX_VALID(ap, idx))
514 			uu_panic("uu_avl_insert(%p, %p, %p): %s\n",
515 			    (void *)ap, elem, (void *)idx,
516 			    INDEX_CHECK(idx)? "outdated index" :
517 			    "invalid index");
518 
519 		/*
520 		 * invalidate outstanding uu_avl_index_ts.
521 		 */
522 		ap->ua_index = INDEX_NEXT(ap->ua_index);
523 	}
524 	avl_insert(&ap->ua_tree, elem, INDEX_DECODE(idx));
525 }
526 
527 void *
528 uu_avl_nearest_next(uu_avl_t *ap, uu_avl_index_t idx)
529 {
530 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
531 		uu_panic("uu_avl_nearest_next(%p, %p): %s\n",
532 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
533 		    "outdated index" : "invalid index");
534 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_AFTER));
535 }
536 
537 void *
538 uu_avl_nearest_prev(uu_avl_t *ap, uu_avl_index_t idx)
539 {
540 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
541 		uu_panic("uu_avl_nearest_prev(%p, %p): %s\n",
542 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
543 		    "outdated index" : "invalid index");
544 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_BEFORE));
545 }
546 
547 /*
548  * called from uu_lockup() and uu_release(), as part of our fork1()-safety.
549  */
550 void
551 uu_avl_lockup(void)
552 {
553 	uu_avl_pool_t *pp;
554 
555 	(void) pthread_mutex_lock(&uu_apool_list_lock);
556 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
557 	    pp = pp->uap_next)
558 		(void) pthread_mutex_lock(&pp->uap_lock);
559 }
560 
561 void
562 uu_avl_release(void)
563 {
564 	uu_avl_pool_t *pp;
565 
566 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
567 	    pp = pp->uap_next)
568 		(void) pthread_mutex_unlock(&pp->uap_lock);
569 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
570 }
571