Commit | Line | Data |
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dff86257 MD |
1 | /* |
2 | * urcu-rbtree.c | |
3 | * | |
4 | * Userspace RCU library - Red-Black Tree | |
5 | * | |
6 | * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | * | |
22 | * Implementation of RCU-adapted data structures and operations based on the RB | |
23 | * tree algorithms found in chapter 12 of: | |
24 | * | |
25 | * Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and | |
26 | * Clifford Stein. Introduction to Algorithms, Third Edition. The MIT | |
27 | * Press, September 2009. | |
28 | */ | |
29 | ||
30 | #define _BSD_SOURCE | |
31 | #define _LGPL_SOURCE | |
32 | ||
33 | #include <stdio.h> | |
34 | #include <pthread.h> | |
35 | #include <assert.h> | |
269a9ef6 | 36 | #include <string.h> |
230dd288 | 37 | #include <unistd.h> |
8f354bc4 | 38 | #include <errno.h> |
dff86257 MD |
39 | |
40 | #include <urcu/rcurbtree.h> | |
41 | #include <urcu-pointer.h> | |
c479601c | 42 | #include <urcu-call-rcu.h> |
dca45c9f | 43 | #include <urcu/compiler.h> |
dff86257 | 44 | |
ae46d4ae MD |
45 | /* |
46 | * Explanation of next/prev walk coherency and search coherency when | |
47 | * performed concurrently with updates. | |
48 | * | |
49 | * next/prev walk coherency with respect to concurrent updates: | |
50 | * | |
51 | * There are 3 scenarios for which we need to model and validate this: | |
52 | * rotation, transplant and "teleportation" (the latter being a remote | |
53 | * transplant in a remove non-nil case). | |
54 | * | |
55 | * - rotation left (right is symmetric) | |
56 | * xl and yr point to the same parent nodes before/after left | |
57 | * rotation. yll and ylr also point to the same parent node | |
58 | * before/after left rotation. | |
59 | * As we are copying x, y and yl (the 3 nodes which parent/child | |
60 | * relationship are changed) to "new" version of this node cluster, | |
61 | * all external references to the cluster either point to the old | |
62 | * cluster or the new one. If we take this cluster as a "black box" | |
63 | * from the point of view of next/prev traversal, all we have to | |
64 | * ensure is that the old and the new cluster behave in the exact same | |
65 | * way with respect to traversal order. | |
66 | * | |
67 | * - transplant | |
68 | * In this operation, we transplant a copy of "v" into its parent | |
69 | * location (u), thus replacing it. The children of "v", vl and vr, | |
70 | * still point to v (new version) after the transplant, so it does not | |
71 | * change the behavior when considering the next/prev traversal. "v" | |
72 | * being copied to a new version ensures that the parent pointers of v | |
73 | * are pointing to its new parent (parent of u) before it is published | |
74 | * to readers (by setting the child pointer of u's parent to the new | |
75 | * copy of v). | |
76 | * | |
77 | * - teleportation | |
78 | * This one is probably the most tricky and will require some ascii | |
79 | * art to explain. | |
80 | * | |
81 | * We want to remove z from this tree: | |
82 | * | |
83 | * zp | |
84 | * \ | |
85 | * z | |
86 | * / \ | |
87 | * zl zr | |
88 | * / | |
89 | * a | |
90 | * / \ | |
91 | * b ar | |
92 | * / \ | |
93 | * y br | |
94 | * \ | |
95 | * yr | |
96 | * / \ | |
97 | * yrl yrr | |
98 | * | |
99 | * What we are going to do is to "teleport" y into z's location, | |
100 | * reparenting yr to b. We are taking care to create a new cluster | |
101 | * copy that is isolated from any reader. We will represent the new | |
102 | * members of the cluster with capital letters. | |
103 | * | |
104 | * zp | |
105 | * \ | |
106 | * Y | |
107 | * / \ | |
108 | * zl ZR | |
109 | * / | |
110 | * A | |
111 | * / \ | |
112 | * B ar | |
113 | * / \ | |
114 | * YR br | |
115 | * / \ | |
116 | * yrl yrr | |
117 | * | |
118 | * In this transient state, we notice that the pointers within the | |
119 | * cluster all point to the new cluster nodes, and they point to the | |
120 | * correct external nodes. However, no external pointer point to the | |
121 | * cluster (yet). The first pointer to point to this cluster will be | |
122 | * "zp->right". It will therefore make the cluster visible for search. | |
123 | * | |
124 | * In this intermediate state, we can walk through the new cluster | |
125 | * when coming from the top (in a next/prev traversal), but can come | |
126 | * back to the old cluster when going back up from the children nodes. | |
127 | * All we have to ensure is that the two clusters, taken as a black | |
128 | * box from a next/prev traversal perspective, yield to the exact same | |
129 | * result. | |
130 | * | |
131 | * Search coherency with concurrent updates: | |
132 | * | |
133 | * Simple "search" (only going down the tree) is also handled by this | |
134 | * cluster scheme. The explanation is a subset of the prev/next | |
135 | * explanation, where we don't have to care about the intermediate | |
136 | * stages where the children point to the old cluster, because we only | |
137 | * ever use the top level pointers to go down into the children nodes, | |
138 | * we never go back up. So by simply making sure that all the cluster | |
139 | * internal nodes pointers are setup correctly before making the | |
140 | * cluster visible to the readers (by setting the parent pointer to | |
141 | * the topmost new node in the cluster), we are sure that readers will | |
142 | * see a coherent view of the cluster at all times. | |
143 | */ | |
144 | ||
dff86257 MD |
145 | #ifdef DEBUG |
146 | #define dbg_printf(args...) printf(args) | |
9c161ee1 | 147 | #define dbg_usleep(usecs) usleep(usecs) |
dff86257 MD |
148 | #else |
149 | #define dbg_printf(args...) | |
9c161ee1 | 150 | #define dbg_usleep(usecs) |
dff86257 MD |
151 | #endif |
152 | ||
6daf6090 MD |
153 | /* |
154 | * Undefine this to enable the non-RCU rotate and transplant functions | |
2abaffb0 MD |
155 | * (for debugging). Note that these versions don't support the tree |
156 | * max_end updates, so lookups must be performed with | |
157 | * rcu_rbtree_search_begin_key when using this debug facility. | |
6daf6090 | 158 | */ |
dbe4ae98 MD |
159 | #define RBTREE_RCU_SUPPORT_ROTATE_LEFT |
160 | #define RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
6daf6090 | 161 | #define RBTREE_RCU_SUPPORT_TRANSPLANT |
c2ceb27c | 162 | #define RBTREE_RCU_SUPPORT |
6daf6090 | 163 | |
1444707c MD |
164 | /* |
165 | * Add internal mutex locking within the RBTree, for debugging. Enable this | |
166 | * define and add mutexes to RCU readers to debug races with with rotation or | |
167 | * transplant. | |
168 | */ | |
169 | /* #define RBTREE_INTERNAL_LOCKING */ | |
170 | ||
171 | #ifdef RBTREE_INTERNAL_LOCKING | |
230dd288 MD |
172 | static pthread_mutex_t test_mutex = PTHREAD_MUTEX_INITIALIZER; |
173 | static pthread_mutex_t outer_mutex = PTHREAD_MUTEX_INITIALIZER; | |
174 | ||
175 | static | |
176 | void lock_outer_mutex(void) | |
177 | { | |
178 | pthread_mutex_lock(&outer_mutex); | |
179 | } | |
180 | ||
181 | static | |
182 | void unlock_outer_mutex(void) | |
183 | { | |
184 | pthread_mutex_unlock(&outer_mutex); | |
185 | } | |
186 | ||
187 | static | |
188 | void lock_test_mutex(void) | |
189 | { | |
190 | pthread_mutex_lock(&test_mutex); | |
191 | } | |
192 | ||
193 | static | |
194 | void unlock_test_mutex(void) | |
195 | { | |
196 | pthread_mutex_unlock(&test_mutex); | |
197 | } | |
1444707c MD |
198 | #else |
199 | static | |
200 | void lock_outer_mutex(void) | |
201 | { | |
202 | } | |
203 | ||
204 | static | |
205 | void unlock_outer_mutex(void) | |
206 | { | |
207 | } | |
208 | ||
209 | static | |
210 | void lock_test_mutex(void) | |
211 | { | |
212 | } | |
213 | ||
214 | static | |
215 | void unlock_test_mutex(void) | |
216 | { | |
217 | } | |
230dd288 MD |
218 | #endif |
219 | ||
7ba89e62 MD |
220 | static |
221 | void set_parent(struct rcu_rbtree_node *node, | |
222 | struct rcu_rbtree_node *parent, | |
223 | unsigned int pos) | |
224 | { | |
9606ca85 | 225 | _CMM_STORE_SHARED(node->parent, ((unsigned long) parent) | pos); |
7ba89e62 MD |
226 | } |
227 | ||
228 | static | |
229 | struct rcu_rbtree_node *get_parent(struct rcu_rbtree_node *node) | |
230 | { | |
231 | return (struct rcu_rbtree_node *) (node->parent & ~1UL); | |
232 | } | |
233 | ||
234 | static | |
235 | unsigned int get_pos(struct rcu_rbtree_node *node) | |
236 | { | |
237 | return (unsigned int) (node->parent & 1UL); | |
238 | } | |
239 | ||
240 | static | |
241 | struct rcu_rbtree_node *get_parent_and_pos(struct rcu_rbtree_node *node, | |
242 | unsigned int *pos) | |
243 | { | |
244 | unsigned long parent_pos = rcu_dereference(node->parent); | |
245 | ||
246 | *pos = (unsigned int) (parent_pos & 1UL); | |
247 | return (struct rcu_rbtree_node *) (parent_pos & ~1UL); | |
248 | } | |
249 | ||
269a9ef6 MD |
250 | static |
251 | void set_decay(struct rcu_rbtree_node *x, struct rcu_rbtree_node *xc) | |
252 | { | |
253 | x->decay_next = xc; | |
254 | } | |
255 | ||
256 | static | |
257 | struct rcu_rbtree_node *get_decay(struct rcu_rbtree_node *x) | |
258 | { | |
dbe4ae98 MD |
259 | if (!x) |
260 | return NULL; | |
269a9ef6 MD |
261 | while (x->decay_next) |
262 | x = x->decay_next; | |
263 | return x; | |
264 | } | |
265 | ||
266 | static | |
267 | struct rcu_rbtree_node *is_decay(struct rcu_rbtree_node *x) | |
268 | { | |
269 | return x->decay_next; | |
270 | } | |
271 | ||
3c672595 | 272 | static |
8f354bc4 MD |
273 | struct rcu_rbtree_node *_rcu_rbtree_alloc_node(struct rcu_rbtree *rbtree) |
274 | { | |
275 | return rbtree->rballoc(sizeof(struct rcu_rbtree_node)); | |
276 | } | |
277 | ||
278 | static | |
279 | void _rcu_rbtree_free_node(struct rcu_head *head) | |
3c672595 MD |
280 | { |
281 | struct rcu_rbtree_node *node = | |
282 | caa_container_of(head, struct rcu_rbtree_node, head); | |
283 | node->rbtree->rbfree(node); | |
284 | } | |
285 | ||
c2ceb27c MD |
286 | #ifdef RBTREE_RCU_SUPPORT |
287 | ||
269a9ef6 MD |
288 | static |
289 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
290 | struct rcu_rbtree_node *x) | |
291 | { | |
292 | struct rcu_rbtree_node *xc; | |
293 | ||
8ded5fe9 | 294 | if (rcu_rbtree_is_nil(rbtree, x)) |
269a9ef6 MD |
295 | return x; |
296 | ||
8f354bc4 | 297 | xc = _rcu_rbtree_alloc_node(rbtree); |
3c672595 | 298 | memcpy(xc, x, sizeof(*xc)); |
269a9ef6 MD |
299 | xc->decay_next = NULL; |
300 | set_decay(x, xc); | |
1cdd423d | 301 | rbtree->call_rcu(&x->head, _rcu_rbtree_free_node); |
269a9ef6 MD |
302 | return xc; |
303 | } | |
304 | ||
c2ceb27c MD |
305 | #else /* RBTREE_RCU_SUPPORT */ |
306 | ||
307 | static | |
308 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
309 | struct rcu_rbtree_node *x) | |
310 | { | |
311 | return x; | |
312 | } | |
313 | ||
314 | #endif | |
315 | ||
dca45c9f MD |
316 | /* |
317 | * Info for range lookups: | |
318 | * Range lookup information is only valid when used when searching for | |
319 | * ranges. It should never be used in next/prev traversal because the | |
320 | * pointers to parents are not in sync with the parent vision of the | |
321 | * children range. | |
322 | */ | |
323 | static | |
a84e8c8e MD |
324 | void set_left(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
325 | struct rcu_rbtree_node *left) | |
dca45c9f | 326 | { |
dca45c9f | 327 | node->_left = left; |
dca45c9f MD |
328 | } |
329 | ||
330 | static | |
a84e8c8e MD |
331 | void set_right(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
332 | struct rcu_rbtree_node *right) | |
dca45c9f | 333 | { |
dca45c9f | 334 | node->_right = right; |
dca45c9f MD |
335 | } |
336 | ||
66b64c35 MD |
337 | static |
338 | void *calculate_node_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node) | |
339 | { | |
340 | void *max_end; | |
341 | ||
342 | max_end = node->end; | |
343 | if (!rcu_rbtree_is_nil(rbtree, node->_right)) { | |
344 | if (rbtree->comp(max_end, node->_right->max_end) < 0) | |
345 | max_end = node->_right->max_end; | |
346 | } | |
347 | if (!rcu_rbtree_is_nil(rbtree, node->_left)) { | |
348 | if (rbtree->comp(max_end, node->_left->max_end) < 0) | |
349 | max_end = node->_left->max_end; | |
350 | } | |
351 | return max_end; | |
352 | } | |
353 | ||
dff86257 MD |
354 | /* |
355 | * TODO | |
356 | * Deal with memory allocation errors. | |
357 | * Can be ensured by reserving a pool of memory entries before doing the | |
358 | * insertion, which will have to be function of number of | |
e20fb727 MD |
359 | * transplantations/rotations required for the operation (which is a |
360 | * multiple of the tree height). | |
dff86257 MD |
361 | */ |
362 | ||
5d2c985d | 363 | #ifdef DEBUG |
dff86257 MD |
364 | static |
365 | void show_tree(struct rcu_rbtree *rbtree) | |
366 | { | |
367 | struct rcu_rbtree_node *node; | |
368 | ||
369 | node = rcu_rbtree_min(rbtree, rbtree->root); | |
8ded5fe9 | 370 | while (!rcu_rbtree_is_nil(rbtree, node)) { |
269a9ef6 | 371 | assert(!is_decay(node)); |
fcb4eea8 | 372 | printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ", |
3366b9c0 MD |
373 | (unsigned long) node->begin, |
374 | (unsigned long) node->end, | |
375 | (unsigned long) get_parent(node)->begin, | |
fcb4eea8 MD |
376 | (unsigned long) node->_right->begin, |
377 | (unsigned long) node->_left->begin, | |
dff86257 | 378 | node->color ? "red" : "black", |
7ba89e62 | 379 | get_pos(node) ? "right" : "left", |
a84e8c8e | 380 | rcu_rbtree_is_nil(rbtree, node) ? "nil" : ""); |
dff86257 MD |
381 | node = rcu_rbtree_next(rbtree, node); |
382 | } | |
383 | printf("\n"); | |
384 | } | |
66b64c35 MD |
385 | |
386 | #define check_max_end(rbtree, x) \ | |
387 | do { \ | |
388 | if (rcu_rbtree_is_nil(rbtree, x)) \ | |
389 | break; \ | |
390 | assert(rbtree->comp(x->max_end, \ | |
391 | calculate_node_max_end(rbtree, x)) == 0); \ | |
392 | } while (0) | |
393 | ||
5d2c985d MD |
394 | #else /* DEBUG */ |
395 | static | |
396 | void show_tree(struct rcu_rbtree *rbtree) | |
397 | { | |
398 | } | |
66b64c35 MD |
399 | |
400 | static | |
401 | void check_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *x) | |
402 | { | |
403 | } | |
5d2c985d | 404 | #endif /* DEBUG */ |
dff86257 MD |
405 | |
406 | static | |
407 | struct rcu_rbtree_node *make_nil(struct rcu_rbtree *rbtree) | |
408 | { | |
409 | return &rbtree->nil_node; | |
410 | } | |
411 | ||
412 | /* | |
413 | * Iterative rbtree search. | |
414 | */ | |
00539351 | 415 | struct rcu_rbtree_node *rcu_rbtree_search(struct rcu_rbtree *rbtree, |
66b64c35 MD |
416 | struct rcu_rbtree_node *x, |
417 | void *point) | |
418 | { | |
419 | struct rcu_rbtree_node *xl; | |
420 | ||
421 | dbg_printf("searching point 0x%lx\n", (unsigned long) point); | |
422 | x = rcu_dereference(x); | |
423 | ||
424 | while (!rcu_rbtree_is_nil(rbtree, x)) { | |
425 | dbg_usleep(10); | |
426 | xl = rcu_dereference(x->_left); | |
427 | dbg_printf("search x %lx x_end %lx x_max_end %lx\n", (unsigned long) x->begin, | |
428 | (unsigned long) x->end, (unsigned long) x->max_end); | |
429 | dbg_printf("search xl %lx xl_end %lx xl_max_end %lx\n", (unsigned long) xl->begin, | |
430 | (unsigned long) xl->end, (unsigned long) xl->max_end); | |
431 | if (!rcu_rbtree_is_nil(rbtree, xl) | |
432 | && (rbtree->comp(xl->max_end, point) > 0)) { | |
433 | dbg_printf("go left\n"); | |
434 | x = xl; | |
3d8a234b | 435 | } else if (rbtree->comp(x->begin, point) <= 0 |
66b64c35 MD |
436 | && rbtree->comp(point, x->end) < 0) { |
437 | dbg_printf("got it!\n"); | |
438 | break; | |
439 | } else if (rbtree->comp(point, x->begin) > 0) { | |
440 | dbg_printf("go right\n"); | |
441 | x = rcu_dereference(x->_right); | |
442 | } else { | |
443 | dbg_printf("not found!\n"); | |
444 | x = make_nil(rbtree); | |
445 | } | |
446 | } | |
447 | if (rcu_rbtree_is_nil(rbtree, x)) | |
448 | dbg_printf("Reached bottom of tree.\n"); | |
449 | ||
450 | return x; | |
451 | } | |
452 | ||
453 | struct rcu_rbtree_node *rcu_rbtree_search_range(struct rcu_rbtree *rbtree, | |
454 | struct rcu_rbtree_node *x, | |
455 | void *begin, void *end) | |
456 | { | |
457 | struct rcu_rbtree_node *node; | |
458 | ||
459 | node = rcu_rbtree_search(rbtree, x, begin); | |
460 | if (rcu_rbtree_is_nil(rbtree, node)) | |
461 | return node; | |
462 | if (rbtree->comp(node->end, end) < 0) | |
463 | return NULL; /* High is outside lookup range */ | |
464 | return node; | |
465 | } | |
466 | ||
467 | /* | |
468 | * Search by exact range start value. | |
469 | */ | |
470 | struct rcu_rbtree_node *rcu_rbtree_search_begin_key(struct rcu_rbtree *rbtree, | |
dff86257 MD |
471 | struct rcu_rbtree_node *x, |
472 | void *k) | |
473 | { | |
474 | x = rcu_dereference(x); | |
ac5f3963 | 475 | int comp; |
dff86257 | 476 | |
3366b9c0 | 477 | while (!rcu_rbtree_is_nil(rbtree, x) && (comp = rbtree->comp(k, x->begin)) != 0) { |
9c161ee1 | 478 | dbg_usleep(10); |
ac5f3963 | 479 | if (comp < 0) |
dca45c9f | 480 | x = rcu_dereference(x->_left); |
dff86257 | 481 | else |
dca45c9f | 482 | x = rcu_dereference(x->_right); |
dff86257 MD |
483 | } |
484 | return x; | |
485 | } | |
486 | ||
230dd288 MD |
487 | static |
488 | struct rcu_rbtree_node *rcu_rbtree_min_dup_decay(struct rcu_rbtree *rbtree, | |
489 | struct rcu_rbtree_node *x, | |
490 | struct rcu_rbtree_node **zr) | |
491 | { | |
492 | struct rcu_rbtree_node *xl; | |
493 | ||
494 | x = rcu_dereference(x); | |
495 | ||
8ded5fe9 | 496 | if (rcu_rbtree_is_nil(rbtree, x)) { |
230dd288 MD |
497 | *zr = x; |
498 | return x; | |
499 | } else | |
500 | *zr = x = dup_decay_node(rbtree, x); | |
501 | ||
8ded5fe9 | 502 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 503 | x = dup_decay_node(rbtree, xl); |
7ba89e62 | 504 | set_parent(x, get_decay(get_parent(x)), get_pos(x)); |
dca45c9f | 505 | get_parent(x)->_left = get_decay(get_parent(x)->_left); |
230dd288 MD |
506 | } |
507 | return x; | |
508 | } | |
509 | ||
510 | static | |
511 | struct rcu_rbtree_node *rcu_rbtree_min_update_decay(struct rcu_rbtree *rbtree, | |
512 | struct rcu_rbtree_node *x) | |
513 | { | |
514 | struct rcu_rbtree_node *xl; | |
515 | ||
516 | x = rcu_dereference(x); | |
517 | ||
8ded5fe9 | 518 | if (rcu_rbtree_is_nil(rbtree, x)) |
230dd288 MD |
519 | return x; |
520 | else { | |
dca45c9f MD |
521 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
522 | get_pos(x->_right)); | |
523 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
524 | get_pos(x->_left)); | |
230dd288 MD |
525 | } |
526 | ||
8ded5fe9 | 527 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 528 | x = xl; |
dca45c9f MD |
529 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
530 | get_pos(x->_right)); | |
531 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
532 | get_pos(x->_left)); | |
230dd288 MD |
533 | } |
534 | return x; | |
535 | } | |
536 | ||
dff86257 MD |
537 | struct rcu_rbtree_node *rcu_rbtree_min(struct rcu_rbtree *rbtree, |
538 | struct rcu_rbtree_node *x) | |
539 | { | |
540 | struct rcu_rbtree_node *xl; | |
541 | ||
542 | x = rcu_dereference(x); | |
543 | ||
8ded5fe9 | 544 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
545 | return x; |
546 | ||
8ded5fe9 | 547 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
dff86257 MD |
548 | x = xl; |
549 | return x; | |
550 | } | |
551 | ||
552 | struct rcu_rbtree_node *rcu_rbtree_max(struct rcu_rbtree *rbtree, | |
553 | struct rcu_rbtree_node *x) | |
554 | { | |
555 | struct rcu_rbtree_node *xr; | |
556 | ||
557 | x = rcu_dereference(x); | |
558 | ||
8ded5fe9 | 559 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
560 | return x; |
561 | ||
8ded5fe9 | 562 | while (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 MD |
563 | x = xr; |
564 | return x; | |
565 | } | |
566 | ||
dff86257 | 567 | /* |
7ba89e62 MD |
568 | * RCU read lock must be held across the next/prev calls to ensure validity of |
569 | * the returned node. | |
dff86257 MD |
570 | */ |
571 | struct rcu_rbtree_node *rcu_rbtree_next(struct rcu_rbtree *rbtree, | |
572 | struct rcu_rbtree_node *x) | |
573 | { | |
269a9ef6 | 574 | struct rcu_rbtree_node *xr, *y; |
7ba89e62 | 575 | unsigned int x_pos; |
dff86257 MD |
576 | |
577 | x = rcu_dereference(x); | |
578 | ||
8ded5fe9 | 579 | if (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 | 580 | return rcu_rbtree_min(rbtree, xr); |
7ba89e62 | 581 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 582 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_RIGHT) { |
dff86257 | 583 | x = y; |
7ba89e62 | 584 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
585 | } |
586 | return y; | |
587 | } | |
588 | ||
589 | struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree *rbtree, | |
590 | struct rcu_rbtree_node *x) | |
591 | { | |
269a9ef6 | 592 | struct rcu_rbtree_node *xl, *y; |
7ba89e62 | 593 | unsigned int x_pos; |
dff86257 MD |
594 | |
595 | x = rcu_dereference(x); | |
596 | ||
8ded5fe9 | 597 | if (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
4aa30442 | 598 | return rcu_rbtree_max(rbtree, xl); |
7ba89e62 | 599 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 600 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_LEFT) { |
dff86257 | 601 | x = y; |
7ba89e62 | 602 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
603 | } |
604 | return y; | |
605 | } | |
606 | ||
7bc64d1d MD |
607 | /* |
608 | * "node" needs to be non-visible by readers. | |
609 | */ | |
610 | static | |
611 | void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, | |
fcb4eea8 | 612 | unsigned int copy_parents, struct rcu_rbtree_node *stop) |
7bc64d1d MD |
613 | { |
614 | struct rcu_rbtree_node *prev = NULL, *orig_node = node, *top; | |
615 | ||
616 | do { | |
617 | void *max_end; | |
618 | ||
fcb4eea8 | 619 | assert(node); |
7bc64d1d | 620 | assert(!rcu_rbtree_is_nil(rbtree, node)); |
4459c487 | 621 | |
66b64c35 MD |
622 | if (prev && copy_parents) { |
623 | node = dup_decay_node(rbtree, node); | |
624 | if (get_pos(prev) == IS_RIGHT) | |
625 | node->_right = prev; | |
626 | else | |
627 | node->_left = prev; | |
628 | set_parent(prev, node, get_pos(prev)); | |
629 | } | |
630 | ||
fda7316a | 631 | max_end = calculate_node_max_end(rbtree, node); |
66b64c35 MD |
632 | /* |
633 | * Compare the node max_end keys to make sure we replace | |
634 | * references to a key belonging to a node we remove | |
635 | * from the tree. Otherwise we would still be using this | |
636 | * pointer as an invalid reference after garbage | |
637 | * collection of the node and of its associated | |
638 | * begin/end pointers. | |
639 | */ | |
640 | if (max_end != node->max_end) { | |
7bc64d1d MD |
641 | node->max_end = max_end; |
642 | } else { | |
7bc64d1d MD |
643 | top = get_parent(node); |
644 | cmm_smp_wmb(); /* write into node before publish */ | |
645 | /* make new branch visible to readers */ | |
646 | if (rcu_rbtree_is_nil(rbtree, top)) | |
647 | _CMM_STORE_SHARED(rbtree->root, node); | |
648 | if (get_pos(node) == IS_LEFT) | |
649 | _CMM_STORE_SHARED(top->_left, node); | |
650 | else | |
651 | _CMM_STORE_SHARED(top->_right, node); | |
652 | goto end; | |
653 | } | |
fcb4eea8 MD |
654 | |
655 | /* Check for propagation stop */ | |
656 | if (node == stop) | |
657 | return; | |
658 | ||
7bc64d1d | 659 | prev = node; |
fcb4eea8 MD |
660 | node = get_parent(node); |
661 | } while (!rcu_rbtree_is_nil(rbtree, node)); | |
7bc64d1d MD |
662 | |
663 | top = node; /* nil */ | |
664 | cmm_smp_wmb(); /* write into node before publish */ | |
665 | /* make new branch visible to readers */ | |
666 | _CMM_STORE_SHARED(rbtree->root, prev); | |
667 | ||
668 | end: | |
fcb4eea8 MD |
669 | if (!copy_parents) |
670 | return; | |
7bc64d1d MD |
671 | /* update children */ |
672 | node = orig_node; | |
673 | do { | |
674 | assert(!rcu_rbtree_is_nil(rbtree, node)); | |
675 | set_parent(node->_left, get_decay(get_parent(node->_left)), IS_LEFT); | |
676 | set_parent(node->_right, get_decay(get_parent(node->_right)), IS_RIGHT); | |
677 | } while ((node = get_parent(node)) != top); | |
678 | } | |
679 | ||
dff86257 MD |
680 | /* |
681 | * We have to ensure these assumptions are correct for prev/next | |
682 | * traversal: | |
683 | * | |
684 | * with x being a right child, the assumption that: | |
dca45c9f | 685 | * get_parent(x)->_right == x |
dff86257 | 686 | * or if x is a left child, the assumption that: |
dca45c9f | 687 | * get_parent(x)->_left == x |
dff86257 MD |
688 | * |
689 | * This explains why we have to allocate a vc copy of the node for left_rotate, | |
690 | * right_rotate and transplant operations. | |
691 | * | |
692 | * We always ensure that the right/left child and correct parent is set in the | |
693 | * node copies *before* we reparent the children and make the upper-level point | |
694 | * to the copy. | |
695 | */ | |
696 | ||
697 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
698 | /* Should be eventually followed by a cmm_smp_wmc() */ | |
dff86257 | 699 | |
dbe4ae98 MD |
700 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_LEFT |
701 | ||
dff86257 | 702 | static |
269a9ef6 MD |
703 | void left_rotate(struct rcu_rbtree *rbtree, |
704 | struct rcu_rbtree_node *x) | |
dff86257 | 705 | { |
a84e8c8e | 706 | struct rcu_rbtree_node *y, *y_left; |
dff86257 | 707 | |
66b64c35 MD |
708 | dbg_printf("left rotate %lx\n", (unsigned long) x->begin); |
709 | ||
dca45c9f MD |
710 | y = x->_right; |
711 | y_left = y->_left; | |
269a9ef6 MD |
712 | |
713 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
714 | x = dup_decay_node(rbtree, x); |
715 | y = dup_decay_node(rbtree, y); | |
716 | y_left = dup_decay_node(rbtree, y_left); | |
269a9ef6 | 717 | |
66b64c35 MD |
718 | check_max_end(rbtree, get_parent(x)); |
719 | check_max_end(rbtree, x); | |
720 | check_max_end(rbtree, y); | |
721 | ||
676dd8b6 | 722 | /* Internal node modifications */ |
7ba89e62 MD |
723 | set_parent(y, get_parent(x), get_pos(x)); |
724 | set_parent(x, y, IS_LEFT); | |
a84e8c8e MD |
725 | set_left(rbtree, y, x); |
726 | set_right(rbtree, x, y_left); | |
dca45c9f | 727 | |
8ded5fe9 | 728 | if (!rcu_rbtree_is_nil(rbtree, y_left)) |
7ba89e62 | 729 | set_parent(y_left, x, IS_RIGHT); |
676dd8b6 | 730 | |
fda7316a MD |
731 | /* |
732 | * We only changed the relative position of x and y wrt their | |
733 | * children, and reparented y (but are keeping the same nodes in | |
734 | * place, so its parent does not need to have end value | |
735 | * recalculated). | |
736 | */ | |
737 | x->max_end = calculate_node_max_end(rbtree, x); | |
738 | y->max_end = calculate_node_max_end(rbtree, y); | |
739 | ||
676dd8b6 MD |
740 | cmm_smp_wmb(); /* write into node before publish */ |
741 | ||
742 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
743 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
744 | _CMM_STORE_SHARED(rbtree->root, y); | |
745 | else if (get_pos(y) == IS_LEFT) | |
746 | _CMM_STORE_SHARED(get_parent(y)->_left, y); | |
676dd8b6 | 747 | else |
a84e8c8e | 748 | _CMM_STORE_SHARED(get_parent(y)->_right, y); |
676dd8b6 | 749 | |
dbe4ae98 | 750 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
751 | set_parent(x->_left, get_decay(get_parent(x->_left)), |
752 | get_pos(x->_left)); | |
753 | set_parent(y->_right, get_decay(get_parent(y->_right)), | |
754 | get_pos(y->_right)); | |
8ded5fe9 | 755 | if (!rcu_rbtree_is_nil(rbtree, y_left)) { |
dca45c9f MD |
756 | set_parent(y_left->_right, |
757 | get_decay(get_parent(y_left->_right)), | |
758 | get_pos(y_left->_right)); | |
759 | set_parent(y_left->_left, | |
760 | get_decay(get_parent(y_left->_left)), | |
761 | get_pos(y_left->_left)); | |
dbe4ae98 | 762 | } |
269a9ef6 MD |
763 | |
764 | /* Sanity checks */ | |
dca45c9f MD |
765 | assert(y == rbtree->root || get_parent(y)->_left == y |
766 | || get_parent(y)->_right == y); | |
767 | assert(x == rbtree->root || get_parent(x)->_left == x | |
768 | || get_parent(x)->_right == x); | |
8ded5fe9 MD |
769 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); |
770 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); | |
771 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
772 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
269a9ef6 MD |
773 | assert(!is_decay(rbtree->root)); |
774 | assert(!is_decay(x)); | |
775 | assert(!is_decay(y)); | |
dca45c9f MD |
776 | assert(!is_decay(x->_right)); |
777 | assert(!is_decay(x->_left)); | |
778 | assert(!is_decay(y->_right)); | |
779 | assert(!is_decay(y->_left)); | |
66b64c35 MD |
780 | check_max_end(rbtree, get_parent(y)); |
781 | check_max_end(rbtree, x); | |
782 | check_max_end(rbtree, y); | |
dff86257 MD |
783 | } |
784 | ||
dbe4ae98 MD |
785 | #else |
786 | ||
787 | /* non-rcu version */ | |
788 | static | |
789 | void left_rotate(struct rcu_rbtree *rbtree, | |
790 | struct rcu_rbtree_node *x) | |
791 | { | |
792 | struct rcu_rbtree_node *y; | |
793 | ||
230dd288 | 794 | lock_test_mutex(); |
dca45c9f MD |
795 | y = x->_right; |
796 | x->_right = y->_left; | |
8ded5fe9 | 797 | if (!rcu_rbtree_is_nil(rbtree, y->_left)) |
dca45c9f | 798 | set_parent(y->_left, x, IS_RIGHT); |
7ba89e62 | 799 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 800 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
dbe4ae98 | 801 | rbtree->root = y; |
dca45c9f MD |
802 | else if (x == get_parent(x)->_left) { |
803 | get_parent(x)->_left = y; | |
dbe4ae98 | 804 | } else { |
dca45c9f | 805 | get_parent(x)->_right = y; |
dbe4ae98 | 806 | } |
dca45c9f | 807 | y->_left = x; |
7ba89e62 | 808 | set_parent(x, y, IS_LEFT); |
1444707c MD |
809 | |
810 | /* | |
811 | * We only changed the relative position of x and y wrt their | |
812 | * children, and reparented y (but are keeping the same nodes in | |
813 | * place, so its parent does not need to have end value | |
814 | * recalculated). | |
815 | */ | |
816 | x->max_end = calculate_node_max_end(rbtree, x); | |
817 | y->max_end = calculate_node_max_end(rbtree, y); | |
818 | ||
230dd288 | 819 | unlock_test_mutex(); |
dbe4ae98 MD |
820 | } |
821 | ||
822 | #endif | |
823 | ||
824 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
dff86257 | 825 | static |
269a9ef6 MD |
826 | void right_rotate(struct rcu_rbtree *rbtree, |
827 | struct rcu_rbtree_node *x) | |
dff86257 | 828 | { |
a84e8c8e | 829 | struct rcu_rbtree_node *y, *y_right; |
dff86257 | 830 | |
66b64c35 MD |
831 | dbg_printf("right rotate %lx\n", (unsigned long) x->begin); |
832 | ||
dca45c9f MD |
833 | y = x->_left; |
834 | y_right = y->_right; | |
269a9ef6 MD |
835 | |
836 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
837 | x = dup_decay_node(rbtree, x); |
838 | y = dup_decay_node(rbtree, y); | |
839 | y_right = dup_decay_node(rbtree, y_right); | |
269a9ef6 | 840 | |
66b64c35 MD |
841 | check_max_end(rbtree, get_parent(x)); |
842 | check_max_end(rbtree, x); | |
843 | check_max_end(rbtree, y); | |
844 | ||
676dd8b6 | 845 | /* Internal node modifications */ |
7ba89e62 MD |
846 | set_parent(y, get_parent(x), get_pos(x)); |
847 | set_parent(x, y, IS_RIGHT); | |
a84e8c8e MD |
848 | set_right(rbtree, y, x); |
849 | set_left(rbtree, x, y_right); | |
dca45c9f | 850 | |
8ded5fe9 | 851 | if (!rcu_rbtree_is_nil(rbtree, y_right)) |
7ba89e62 | 852 | set_parent(y_right, x, IS_LEFT); |
676dd8b6 | 853 | |
fda7316a MD |
854 | /* |
855 | * We only changed the relative position of x and y wrt their | |
856 | * children, and reparented y (but are keeping the same nodes in | |
857 | * place, so its parent does not need to have end value | |
858 | * recalculated). | |
859 | */ | |
860 | x->max_end = calculate_node_max_end(rbtree, x); | |
861 | y->max_end = calculate_node_max_end(rbtree, y); | |
862 | ||
676dd8b6 MD |
863 | cmm_smp_wmb(); /* write into node before publish */ |
864 | ||
865 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
866 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
867 | _CMM_STORE_SHARED(rbtree->root, y); | |
868 | else if (get_pos(y) == IS_RIGHT) | |
869 | _CMM_STORE_SHARED(get_parent(y)->_right, y); | |
676dd8b6 | 870 | else |
a84e8c8e | 871 | _CMM_STORE_SHARED(get_parent(y)->_left, y); |
676dd8b6 | 872 | |
dbe4ae98 | 873 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
874 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
875 | get_pos(x->_right)); | |
876 | set_parent(y->_left, get_decay(get_parent(y->_left)), | |
877 | get_pos(y->_left)); | |
8ded5fe9 | 878 | if (!rcu_rbtree_is_nil(rbtree, y_right)) { |
dca45c9f MD |
879 | set_parent(y_right->_left, |
880 | get_decay(get_parent(y_right->_left)), | |
881 | get_pos(y_right->_left)); | |
882 | set_parent(y_right->_right, | |
883 | get_decay(get_parent(y_right->_right)), | |
884 | get_pos(y_right->_right)); | |
dbe4ae98 | 885 | } |
269a9ef6 MD |
886 | |
887 | /* Sanity checks */ | |
dca45c9f MD |
888 | assert(y == rbtree->root || get_parent(y)->_right == y |
889 | || get_parent(y)->_left == y); | |
890 | assert(x == rbtree->root || get_parent(x)->_right == x | |
891 | || get_parent(x)->_left == x); | |
8ded5fe9 MD |
892 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); |
893 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); | |
894 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
895 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
269a9ef6 MD |
896 | assert(!is_decay(rbtree->root)); |
897 | assert(!is_decay(x)); | |
898 | assert(!is_decay(y)); | |
dca45c9f MD |
899 | assert(!is_decay(x->_left)); |
900 | assert(!is_decay(x->_right)); | |
901 | assert(!is_decay(y->_left)); | |
902 | assert(!is_decay(y->_right)); | |
66b64c35 MD |
903 | check_max_end(rbtree, x); |
904 | check_max_end(rbtree, y); | |
905 | check_max_end(rbtree, get_parent(y)); | |
dff86257 MD |
906 | } |
907 | ||
6daf6090 MD |
908 | #else |
909 | ||
dbe4ae98 | 910 | /* non-rcu version */ |
6daf6090 MD |
911 | static |
912 | void right_rotate(struct rcu_rbtree *rbtree, | |
913 | struct rcu_rbtree_node *x) | |
914 | { | |
915 | struct rcu_rbtree_node *y; | |
916 | ||
230dd288 | 917 | lock_test_mutex(); |
dca45c9f MD |
918 | y = x->_left; |
919 | x->_left = y->_right; | |
8ded5fe9 | 920 | if (!rcu_rbtree_is_nil(rbtree, y->_right)) |
dca45c9f | 921 | set_parent(y->_right, x, IS_LEFT); |
7ba89e62 | 922 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 923 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
6daf6090 | 924 | rbtree->root = y; |
dca45c9f MD |
925 | else if (x == get_parent(x)->_right) { |
926 | get_parent(x)->_right = y; | |
6daf6090 | 927 | } else { |
dca45c9f | 928 | get_parent(x)->_left = y; |
6daf6090 | 929 | } |
dca45c9f | 930 | y->_right = x; |
7ba89e62 | 931 | set_parent(x, y, IS_RIGHT); |
1444707c MD |
932 | |
933 | /* | |
934 | * We only changed the relative position of x and y wrt their | |
935 | * children, and reparented y (but are keeping the same nodes in | |
936 | * place, so its parent does not need to have end value | |
937 | * recalculated). | |
938 | */ | |
939 | x->max_end = calculate_node_max_end(rbtree, x); | |
940 | y->max_end = calculate_node_max_end(rbtree, y); | |
941 | ||
230dd288 | 942 | unlock_test_mutex(); |
6daf6090 MD |
943 | } |
944 | ||
945 | #endif | |
946 | ||
dff86257 MD |
947 | static void rcu_rbtree_insert_fixup(struct rcu_rbtree *rbtree, |
948 | struct rcu_rbtree_node *z) | |
949 | { | |
950 | struct rcu_rbtree_node *y; | |
951 | ||
3366b9c0 | 952 | dbg_printf("insert fixup %p\n", z->begin); |
269a9ef6 | 953 | assert(!is_decay(rbtree->root)); |
dff86257 | 954 | |
7ba89e62 | 955 | while (get_parent(z)->color == COLOR_RED) { |
dca45c9f MD |
956 | if (get_parent(z) == get_parent(get_parent(z))->_left) { |
957 | y = get_parent(get_parent(z))->_right; | |
dff86257 | 958 | if (y->color == COLOR_RED) { |
7ba89e62 | 959 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 960 | y->color = COLOR_BLACK; |
7ba89e62 MD |
961 | get_parent(get_parent(z))->color = COLOR_RED; |
962 | z = get_parent(get_parent(z)); | |
dff86257 | 963 | } else { |
dca45c9f | 964 | if (z == get_parent(z)->_right) { |
7ba89e62 | 965 | z = get_parent(z); |
dff86257 | 966 | left_rotate(rbtree, z); |
269a9ef6 MD |
967 | z = get_decay(z); |
968 | assert(!is_decay(rbtree->root)); | |
dff86257 | 969 | } |
7ba89e62 MD |
970 | get_parent(z)->color = COLOR_BLACK; |
971 | get_parent(get_parent(z))->color = COLOR_RED; | |
269a9ef6 | 972 | assert(!is_decay(z)); |
7ba89e62 MD |
973 | assert(!is_decay(get_parent(z))); |
974 | assert(!is_decay(get_parent(get_parent(z)))); | |
975 | right_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
976 | assert(!is_decay(z)); |
977 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
978 | } |
979 | } else { | |
dca45c9f | 980 | y = get_parent(get_parent(z))->_left; |
dff86257 | 981 | if (y->color == COLOR_RED) { |
7ba89e62 | 982 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 983 | y->color = COLOR_BLACK; |
7ba89e62 MD |
984 | get_parent(get_parent(z))->color = COLOR_RED; |
985 | z = get_parent(get_parent(z)); | |
dff86257 | 986 | } else { |
dca45c9f | 987 | if (z == get_parent(z)->_left) { |
7ba89e62 | 988 | z = get_parent(z); |
dff86257 | 989 | right_rotate(rbtree, z); |
269a9ef6 MD |
990 | z = get_decay(z); |
991 | assert(!is_decay(rbtree->root)); | |
dff86257 | 992 | } |
7ba89e62 MD |
993 | get_parent(z)->color = COLOR_BLACK; |
994 | get_parent(get_parent(z))->color = COLOR_RED; | |
995 | left_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
996 | assert(!is_decay(z)); |
997 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
998 | } |
999 | } | |
1000 | } | |
1001 | rbtree->root->color = COLOR_BLACK; | |
1002 | } | |
1003 | ||
1004 | /* | |
1005 | * rcu_rbtree_insert - Insert a node in the RCU rbtree | |
1006 | * | |
1007 | * Returns 0 on success, or < 0 on error. | |
1008 | */ | |
1009 | int rcu_rbtree_insert(struct rcu_rbtree *rbtree, | |
3c672595 | 1010 | void *begin, void *end) |
dff86257 | 1011 | { |
3c672595 MD |
1012 | struct rcu_rbtree_node *x, *y, *z; |
1013 | ||
8f354bc4 MD |
1014 | z = _rcu_rbtree_alloc_node(rbtree); |
1015 | if (!z) | |
1016 | return -ENOMEM; | |
3c672595 MD |
1017 | z->begin = begin; |
1018 | z->end = end; | |
dff86257 | 1019 | |
3366b9c0 | 1020 | dbg_printf("insert %p\n", z->begin); |
269a9ef6 | 1021 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1022 | |
1023 | y = make_nil(rbtree); | |
dff86257 | 1024 | x = rbtree->root; |
8ded5fe9 | 1025 | while (!rcu_rbtree_is_nil(rbtree, x)) { |
dff86257 | 1026 | y = x; |
3366b9c0 | 1027 | if (rbtree->comp(z->begin, x->begin) < 0) |
dca45c9f | 1028 | x = x->_left; |
dff86257 | 1029 | else |
dca45c9f | 1030 | x = x->_right; |
dff86257 MD |
1031 | } |
1032 | ||
dca45c9f MD |
1033 | z->_left = make_nil(rbtree); |
1034 | z->_right = make_nil(rbtree); | |
dff86257 | 1035 | z->color = COLOR_RED; |
269a9ef6 | 1036 | z->decay_next = NULL; |
55b5e812 | 1037 | z->max_end = z->end; |
3c672595 | 1038 | z->rbtree = rbtree; |
dff86257 | 1039 | |
8ded5fe9 | 1040 | if (rcu_rbtree_is_nil(rbtree, y)) { |
7bc64d1d | 1041 | set_parent(z, y, IS_RIGHT); /* pos arbitrary for root node */ |
0bd215cc MD |
1042 | /* |
1043 | * Order stores to z (children/parents) before stores | |
1044 | * that will make it visible to the rest of the tree. | |
1045 | */ | |
1046 | cmm_smp_wmb(); | |
dff86257 | 1047 | _CMM_STORE_SHARED(rbtree->root, z); |
3366b9c0 | 1048 | } else if (rbtree->comp(z->begin, y->begin) < 0) { |
7bc64d1d MD |
1049 | y = dup_decay_node(rbtree, y); |
1050 | set_parent(z, y, IS_LEFT); | |
1051 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 1052 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 1053 | else |
a84e8c8e | 1054 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 1055 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 1056 | } else { |
7bc64d1d MD |
1057 | y = dup_decay_node(rbtree, y); |
1058 | set_parent(z, y, IS_RIGHT); | |
1059 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 1060 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 1061 | else |
a84e8c8e | 1062 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 1063 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 1064 | } |
dff86257 MD |
1065 | rcu_rbtree_insert_fixup(rbtree, z); |
1066 | /* | |
1067 | * Make sure to commit all _CMM_STORE_SHARED() for non-coherent caches. | |
1068 | */ | |
1069 | cmm_smp_wmc(); | |
1070 | show_tree(rbtree); | |
66b64c35 MD |
1071 | check_max_end(rbtree, z); |
1072 | check_max_end(rbtree, y); | |
dff86257 MD |
1073 | |
1074 | return 0; | |
1075 | } | |
1076 | ||
1077 | /* | |
1078 | * Transplant v into u position. | |
dff86257 | 1079 | */ |
6daf6090 MD |
1080 | |
1081 | #ifdef RBTREE_RCU_SUPPORT_TRANSPLANT | |
1082 | ||
269a9ef6 MD |
1083 | static |
1084 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1085 | struct rcu_rbtree_node *u, | |
dca45c9f | 1086 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1087 | unsigned int copy_parents, |
1088 | struct rcu_rbtree_node *stop) | |
dff86257 | 1089 | { |
3366b9c0 | 1090 | dbg_printf("transplant %p\n", v->begin); |
dff86257 | 1091 | |
8ded5fe9 | 1092 | if (!rcu_rbtree_is_nil(rbtree, v)) |
dbe4ae98 | 1093 | v = dup_decay_node(rbtree, v); |
c479601c | 1094 | |
8ded5fe9 | 1095 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
7ba89e62 MD |
1096 | /* pos is arbitrary for root node */ |
1097 | set_parent(v, get_parent(u), IS_RIGHT); | |
c479601c MD |
1098 | cmm_smp_wmb(); /* write into node before publish */ |
1099 | _CMM_STORE_SHARED(rbtree->root, v); | |
dff86257 | 1100 | } else { |
fcb4eea8 MD |
1101 | struct rcu_rbtree_node *vp; |
1102 | ||
1103 | vp = get_parent(u); | |
1104 | if (copy_parents) | |
1105 | vp = dup_decay_node(rbtree, vp); | |
1106 | set_parent(v, vp, get_pos(u)); | |
1107 | if (get_pos(v) == IS_LEFT) | |
1108 | _CMM_STORE_SHARED(vp->_left, v); | |
806967f3 | 1109 | else |
fcb4eea8 MD |
1110 | _CMM_STORE_SHARED(vp->_right, v); |
1111 | populate_node_end(rbtree, vp, copy_parents, stop); | |
66b64c35 | 1112 | check_max_end(rbtree, vp); |
c479601c | 1113 | } |
806967f3 | 1114 | |
dbe4ae98 | 1115 | /* Point children to new copy (parent only used by updates/next/prev) */ |
8ded5fe9 | 1116 | if (!rcu_rbtree_is_nil(rbtree, v)) { |
dca45c9f MD |
1117 | set_parent(v->_right, get_decay(get_parent(v->_right)), |
1118 | get_pos(v->_right)); | |
1119 | set_parent(v->_left, get_decay(get_parent(v->_left)), | |
1120 | get_pos(v->_left)); | |
dff86257 | 1121 | } |
269a9ef6 | 1122 | assert(!is_decay(rbtree->root)); |
66b64c35 | 1123 | check_max_end(rbtree, v); |
dff86257 MD |
1124 | } |
1125 | ||
6daf6090 MD |
1126 | #else |
1127 | ||
1128 | /* Non-RCU version */ | |
1129 | static | |
1130 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1131 | struct rcu_rbtree_node *u, | |
dca45c9f | 1132 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1133 | unsigned int copy_parents, |
1134 | struct rcu_rbtree_node *stop) | |
6daf6090 | 1135 | { |
3366b9c0 | 1136 | dbg_printf("transplant %p\n", v->begin); |
6daf6090 | 1137 | |
230dd288 | 1138 | lock_test_mutex(); |
1444707c | 1139 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
6daf6090 | 1140 | rbtree->root = v; |
1444707c MD |
1141 | } else { |
1142 | if (u == get_parent(u)->_left) | |
1143 | get_parent(u)->_left = v; | |
1144 | else | |
1145 | get_parent(u)->_right = v; | |
1146 | populate_node_end(rbtree, get_parent(u), copy_parents, stop); | |
1147 | } | |
7ba89e62 | 1148 | set_parent(v, get_parent(u), get_pos(u)); |
230dd288 | 1149 | unlock_test_mutex(); |
6daf6090 MD |
1150 | } |
1151 | ||
1152 | #endif | |
1153 | ||
dff86257 MD |
1154 | static void rcu_rbtree_remove_fixup(struct rcu_rbtree *rbtree, |
1155 | struct rcu_rbtree_node *x) | |
1156 | { | |
3366b9c0 | 1157 | dbg_printf("remove fixup %p\n", x->begin); |
dff86257 MD |
1158 | |
1159 | while (x != rbtree->root && x->color == COLOR_BLACK) { | |
7ba89e62 | 1160 | assert(!is_decay(get_parent(x))); |
dca45c9f MD |
1161 | assert(!is_decay(get_parent(x)->_left)); |
1162 | if (x == get_parent(x)->_left) { | |
269a9ef6 | 1163 | struct rcu_rbtree_node *w; |
dff86257 | 1164 | |
dca45c9f | 1165 | w = get_parent(x)->_right; |
dff86257 MD |
1166 | |
1167 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1168 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1169 | get_parent(x)->color = COLOR_RED; |
1170 | left_rotate(rbtree, get_parent(x)); | |
269a9ef6 MD |
1171 | x = get_decay(x); |
1172 | assert(!is_decay(rbtree->root)); | |
dca45c9f | 1173 | w = get_parent(x)->_right; |
dff86257 | 1174 | } |
dca45c9f MD |
1175 | if (w->_left->color == COLOR_BLACK |
1176 | && w->_right->color == COLOR_BLACK) { | |
dff86257 | 1177 | w->color = COLOR_RED; |
7ba89e62 | 1178 | x = get_parent(x); |
c479601c MD |
1179 | assert(!is_decay(rbtree->root)); |
1180 | assert(!is_decay(x)); | |
dff86257 | 1181 | } else { |
dca45c9f MD |
1182 | if (w->_right->color == COLOR_BLACK) { |
1183 | w->_left->color = COLOR_BLACK; | |
dff86257 MD |
1184 | w->color = COLOR_RED; |
1185 | right_rotate(rbtree, w); | |
c479601c | 1186 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1187 | x = get_decay(x); |
dca45c9f | 1188 | w = get_parent(x)->_right; |
dff86257 | 1189 | } |
7ba89e62 MD |
1190 | w->color = get_parent(x)->color; |
1191 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1192 | w->_right->color = COLOR_BLACK; |
7ba89e62 | 1193 | left_rotate(rbtree, get_parent(x)); |
269a9ef6 | 1194 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1195 | x = rbtree->root; |
1196 | } | |
1197 | } else { | |
269a9ef6 | 1198 | struct rcu_rbtree_node *w; |
dff86257 | 1199 | |
dca45c9f | 1200 | w = get_parent(x)->_left; |
dff86257 MD |
1201 | |
1202 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1203 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1204 | get_parent(x)->color = COLOR_RED; |
1205 | right_rotate(rbtree, get_parent(x)); | |
c479601c | 1206 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1207 | x = get_decay(x); |
dca45c9f | 1208 | w = get_parent(x)->_left; |
dff86257 | 1209 | } |
dca45c9f MD |
1210 | if (w->_right->color == COLOR_BLACK |
1211 | && w->_left->color == COLOR_BLACK) { | |
dff86257 | 1212 | w->color = COLOR_RED; |
7ba89e62 | 1213 | x = get_parent(x); |
c479601c MD |
1214 | assert(!is_decay(rbtree->root)); |
1215 | assert(!is_decay(x)); | |
dff86257 | 1216 | } else { |
dca45c9f MD |
1217 | if (w->_left->color == COLOR_BLACK) { |
1218 | w->_right->color = COLOR_BLACK; | |
dff86257 MD |
1219 | w->color = COLOR_RED; |
1220 | left_rotate(rbtree, w); | |
269a9ef6 MD |
1221 | assert(!is_decay(rbtree->root)); |
1222 | x = get_decay(x); | |
dca45c9f | 1223 | w = get_parent(x)->_left; |
dff86257 | 1224 | } |
7ba89e62 MD |
1225 | w->color = get_parent(x)->color; |
1226 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1227 | w->_left->color = COLOR_BLACK; |
7ba89e62 | 1228 | right_rotate(rbtree, get_parent(x)); |
c479601c | 1229 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1230 | x = rbtree->root; |
1231 | } | |
1232 | } | |
1233 | } | |
1234 | x->color = COLOR_BLACK; | |
1235 | } | |
1236 | ||
1237 | /* | |
269a9ef6 MD |
1238 | * Delete z. All non-copied children left/right positions are unchanged. |
1239 | */ | |
1240 | static | |
1241 | void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, | |
1242 | struct rcu_rbtree_node *z, | |
1243 | struct rcu_rbtree_node *y) | |
dff86257 | 1244 | { |
a84e8c8e | 1245 | struct rcu_rbtree_node *x; |
dff86257 | 1246 | |
3366b9c0 | 1247 | dbg_printf("remove nonil %p\n", z->begin); |
dff86257 MD |
1248 | show_tree(rbtree); |
1249 | ||
c479601c MD |
1250 | assert(!is_decay(z)); |
1251 | assert(!is_decay(y)); | |
dca45c9f | 1252 | assert(!is_decay(y->_right)); |
7ba89e62 | 1253 | assert(!is_decay(get_parent(y))); |
dca45c9f | 1254 | x = y->_right; |
c479601c | 1255 | assert(!is_decay(x)); |
7ba89e62 | 1256 | if (get_parent(y) == z) { |
230dd288 | 1257 | y = dup_decay_node(rbtree, y); |
7ba89e62 | 1258 | set_parent(x, y, get_pos(x)); /* parent for nil */ |
66b64c35 | 1259 | /* y is z's right node */ |
a84e8c8e | 1260 | set_left(rbtree, y, z->_left); |
66b64c35 | 1261 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1262 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 MD |
1263 | } else { |
1264 | struct rcu_rbtree_node *oy_right, *z_right; | |
1265 | ||
1266 | /* | |
1267 | * Need to make sure y is always visible by readers. | |
1268 | */ | |
dca45c9f | 1269 | y = rcu_rbtree_min_dup_decay(rbtree, z->_right, &z_right); |
269a9ef6 MD |
1270 | assert(!is_decay(y)); |
1271 | assert(!is_decay(z)); | |
dca45c9f MD |
1272 | oy_right = y->_right; |
1273 | ||
1274 | /* | |
3366b9c0 | 1275 | * The max child begin of z_right does not change, because |
dca45c9f MD |
1276 | * we're only changing its left children. |
1277 | */ | |
1278 | y->_right = z_right; | |
1279 | set_parent(y->_right, y, IS_RIGHT); | |
dca45c9f MD |
1280 | assert(!is_decay(z->_left)); |
1281 | y->_left = z->_left; | |
230dd288 | 1282 | assert(!is_decay(oy_right)); |
dca45c9f MD |
1283 | /* |
1284 | * Transplant of oy_right to old y's location will only | |
fcb4eea8 | 1285 | * trigger a "end" value update of the already copied branch |
dca45c9f MD |
1286 | * (which is not visible yet). We are transplanting |
1287 | * oy_right as a left child of old y's parent, so the | |
1288 | * min values update propagated upward necessarily stops | |
1289 | * at z_right. | |
1290 | */ | |
fcb4eea8 | 1291 | rcu_rbtree_transplant(rbtree, y, oy_right, 0, y); |
66b64c35 | 1292 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1293 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 | 1294 | /* Update children */ |
dca45c9f | 1295 | (void) rcu_rbtree_min_update_decay(rbtree, y->_right); |
dff86257 | 1296 | } |
c479601c | 1297 | y = get_decay(y); |
269a9ef6 | 1298 | assert(!is_decay(z)); |
dca45c9f | 1299 | assert(!is_decay(z->_left)); |
dff86257 | 1300 | y->color = z->color; |
dca45c9f MD |
1301 | set_parent(y->_left, y, IS_LEFT); |
1302 | set_parent(y->_right, get_decay(get_parent(y->_right)), IS_RIGHT); | |
1303 | assert(!is_decay(y->_left)); | |
1304 | assert(!is_decay(y->_right)); | |
dff86257 MD |
1305 | } |
1306 | ||
1307 | int rcu_rbtree_remove(struct rcu_rbtree *rbtree, | |
1308 | struct rcu_rbtree_node *z) | |
1309 | { | |
1310 | struct rcu_rbtree_node *x, *y; | |
1311 | unsigned int y_original_color; | |
1312 | ||
269a9ef6 | 1313 | assert(!is_decay(rbtree->root)); |
3366b9c0 | 1314 | dbg_printf("remove %p\n", z->begin); |
dff86257 MD |
1315 | show_tree(rbtree); |
1316 | ||
c479601c | 1317 | assert(!is_decay(z)); |
dff86257 MD |
1318 | y = z; |
1319 | y_original_color = y->color; | |
1320 | ||
8ded5fe9 | 1321 | if (rcu_rbtree_is_nil(rbtree, z->_left)) { |
fcb4eea8 | 1322 | rcu_rbtree_transplant(rbtree, z, z->_right, 1, NULL); |
269a9ef6 | 1323 | assert(!is_decay(z)); |
dca45c9f | 1324 | x = get_decay(z->_right); |
dff86257 | 1325 | show_tree(rbtree); |
8ded5fe9 | 1326 | } else if (rcu_rbtree_is_nil(rbtree, z->_right)) { |
fcb4eea8 | 1327 | rcu_rbtree_transplant(rbtree, z, z->_left, 1, NULL); |
269a9ef6 | 1328 | assert(!is_decay(z)); |
dca45c9f | 1329 | x = get_decay(z->_left); |
dff86257 MD |
1330 | show_tree(rbtree); |
1331 | } else { | |
dca45c9f | 1332 | y = rcu_rbtree_min(rbtree, z->_right); |
c479601c | 1333 | assert(!is_decay(y)); |
dff86257 | 1334 | y_original_color = y->color; |
dca45c9f | 1335 | x = y->_right; |
269a9ef6 | 1336 | rcu_rbtree_remove_nonil(rbtree, z, y); |
6daf6090 | 1337 | x = get_decay(x); |
dff86257 MD |
1338 | show_tree(rbtree); |
1339 | } | |
1340 | if (y_original_color == COLOR_BLACK) | |
1341 | rcu_rbtree_remove_fixup(rbtree, x); | |
1342 | show_tree(rbtree); | |
66b64c35 MD |
1343 | check_max_end(rbtree, x); |
1344 | check_max_end(rbtree, get_decay(y)); | |
dff86257 MD |
1345 | /* |
1346 | * Commit all _CMM_STORE_SHARED(). | |
1347 | */ | |
1348 | cmm_smp_wmc(); | |
c2ceb27c | 1349 | #ifdef RBTREE_RCU_SUPPORT |
1cdd423d | 1350 | rbtree->call_rcu(&z->head, _rcu_rbtree_free_node); |
c2ceb27c MD |
1351 | #else |
1352 | _rcu_rbtree_free_node(&z->head); | |
1353 | #endif | |
dff86257 MD |
1354 | |
1355 | return 0; | |
1356 | } |