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 MD |
161 | #define RBTREE_RCU_SUPPORT_TRANSPLANT |
162 | ||
230dd288 MD |
163 | #ifdef EXTRA_DEBUG |
164 | static pthread_mutex_t test_mutex = PTHREAD_MUTEX_INITIALIZER; | |
165 | static pthread_mutex_t outer_mutex = PTHREAD_MUTEX_INITIALIZER; | |
166 | ||
167 | static | |
168 | void lock_outer_mutex(void) | |
169 | { | |
170 | pthread_mutex_lock(&outer_mutex); | |
171 | } | |
172 | ||
173 | static | |
174 | void unlock_outer_mutex(void) | |
175 | { | |
176 | pthread_mutex_unlock(&outer_mutex); | |
177 | } | |
178 | ||
179 | static | |
180 | void lock_test_mutex(void) | |
181 | { | |
182 | pthread_mutex_lock(&test_mutex); | |
183 | } | |
184 | ||
185 | static | |
186 | void unlock_test_mutex(void) | |
187 | { | |
188 | pthread_mutex_unlock(&test_mutex); | |
189 | } | |
190 | #endif | |
191 | ||
7ba89e62 MD |
192 | static |
193 | void set_parent(struct rcu_rbtree_node *node, | |
194 | struct rcu_rbtree_node *parent, | |
195 | unsigned int pos) | |
196 | { | |
9606ca85 | 197 | _CMM_STORE_SHARED(node->parent, ((unsigned long) parent) | pos); |
7ba89e62 MD |
198 | } |
199 | ||
200 | static | |
201 | struct rcu_rbtree_node *get_parent(struct rcu_rbtree_node *node) | |
202 | { | |
203 | return (struct rcu_rbtree_node *) (node->parent & ~1UL); | |
204 | } | |
205 | ||
206 | static | |
207 | unsigned int get_pos(struct rcu_rbtree_node *node) | |
208 | { | |
209 | return (unsigned int) (node->parent & 1UL); | |
210 | } | |
211 | ||
212 | static | |
213 | struct rcu_rbtree_node *get_parent_and_pos(struct rcu_rbtree_node *node, | |
214 | unsigned int *pos) | |
215 | { | |
216 | unsigned long parent_pos = rcu_dereference(node->parent); | |
217 | ||
218 | *pos = (unsigned int) (parent_pos & 1UL); | |
219 | return (struct rcu_rbtree_node *) (parent_pos & ~1UL); | |
220 | } | |
221 | ||
269a9ef6 MD |
222 | static |
223 | void set_decay(struct rcu_rbtree_node *x, struct rcu_rbtree_node *xc) | |
224 | { | |
225 | x->decay_next = xc; | |
226 | } | |
227 | ||
228 | static | |
229 | struct rcu_rbtree_node *get_decay(struct rcu_rbtree_node *x) | |
230 | { | |
dbe4ae98 MD |
231 | if (!x) |
232 | return NULL; | |
269a9ef6 MD |
233 | while (x->decay_next) |
234 | x = x->decay_next; | |
235 | return x; | |
236 | } | |
237 | ||
238 | static | |
239 | struct rcu_rbtree_node *is_decay(struct rcu_rbtree_node *x) | |
240 | { | |
241 | return x->decay_next; | |
242 | } | |
243 | ||
3c672595 | 244 | static |
8f354bc4 MD |
245 | struct rcu_rbtree_node *_rcu_rbtree_alloc_node(struct rcu_rbtree *rbtree) |
246 | { | |
247 | return rbtree->rballoc(sizeof(struct rcu_rbtree_node)); | |
248 | } | |
249 | ||
250 | static | |
251 | void _rcu_rbtree_free_node(struct rcu_head *head) | |
3c672595 MD |
252 | { |
253 | struct rcu_rbtree_node *node = | |
254 | caa_container_of(head, struct rcu_rbtree_node, head); | |
255 | node->rbtree->rbfree(node); | |
256 | } | |
257 | ||
269a9ef6 MD |
258 | static |
259 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
260 | struct rcu_rbtree_node *x) | |
261 | { | |
262 | struct rcu_rbtree_node *xc; | |
263 | ||
8ded5fe9 | 264 | if (rcu_rbtree_is_nil(rbtree, x)) |
269a9ef6 MD |
265 | return x; |
266 | ||
8f354bc4 | 267 | xc = _rcu_rbtree_alloc_node(rbtree); |
3c672595 | 268 | memcpy(xc, x, sizeof(*xc)); |
269a9ef6 MD |
269 | xc->decay_next = NULL; |
270 | set_decay(x, xc); | |
1cdd423d | 271 | rbtree->call_rcu(&x->head, _rcu_rbtree_free_node); |
269a9ef6 MD |
272 | return xc; |
273 | } | |
274 | ||
dca45c9f MD |
275 | /* |
276 | * Info for range lookups: | |
277 | * Range lookup information is only valid when used when searching for | |
278 | * ranges. It should never be used in next/prev traversal because the | |
279 | * pointers to parents are not in sync with the parent vision of the | |
280 | * children range. | |
281 | */ | |
282 | static | |
a84e8c8e MD |
283 | void set_left(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
284 | struct rcu_rbtree_node *left) | |
dca45c9f | 285 | { |
dca45c9f | 286 | node->_left = left; |
dca45c9f MD |
287 | } |
288 | ||
289 | static | |
a84e8c8e MD |
290 | void set_right(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
291 | struct rcu_rbtree_node *right) | |
dca45c9f | 292 | { |
dca45c9f | 293 | node->_right = right; |
dca45c9f MD |
294 | } |
295 | ||
66b64c35 MD |
296 | static |
297 | void *calculate_node_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node) | |
298 | { | |
299 | void *max_end; | |
300 | ||
301 | max_end = node->end; | |
302 | if (!rcu_rbtree_is_nil(rbtree, node->_right)) { | |
303 | if (rbtree->comp(max_end, node->_right->max_end) < 0) | |
304 | max_end = node->_right->max_end; | |
305 | } | |
306 | if (!rcu_rbtree_is_nil(rbtree, node->_left)) { | |
307 | if (rbtree->comp(max_end, node->_left->max_end) < 0) | |
308 | max_end = node->_left->max_end; | |
309 | } | |
310 | return max_end; | |
311 | } | |
312 | ||
dff86257 MD |
313 | /* |
314 | * TODO | |
315 | * Deal with memory allocation errors. | |
316 | * Can be ensured by reserving a pool of memory entries before doing the | |
317 | * insertion, which will have to be function of number of | |
e20fb727 MD |
318 | * transplantations/rotations required for the operation (which is a |
319 | * multiple of the tree height). | |
dff86257 MD |
320 | */ |
321 | ||
5d2c985d | 322 | #ifdef DEBUG |
dff86257 MD |
323 | static |
324 | void show_tree(struct rcu_rbtree *rbtree) | |
325 | { | |
326 | struct rcu_rbtree_node *node; | |
327 | ||
328 | node = rcu_rbtree_min(rbtree, rbtree->root); | |
8ded5fe9 | 329 | while (!rcu_rbtree_is_nil(rbtree, node)) { |
269a9ef6 | 330 | assert(!is_decay(node)); |
fcb4eea8 | 331 | printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ", |
3366b9c0 MD |
332 | (unsigned long) node->begin, |
333 | (unsigned long) node->end, | |
334 | (unsigned long) get_parent(node)->begin, | |
fcb4eea8 MD |
335 | (unsigned long) node->_right->begin, |
336 | (unsigned long) node->_left->begin, | |
dff86257 | 337 | node->color ? "red" : "black", |
7ba89e62 | 338 | get_pos(node) ? "right" : "left", |
a84e8c8e | 339 | rcu_rbtree_is_nil(rbtree, node) ? "nil" : ""); |
dff86257 MD |
340 | node = rcu_rbtree_next(rbtree, node); |
341 | } | |
342 | printf("\n"); | |
343 | } | |
66b64c35 MD |
344 | |
345 | #define check_max_end(rbtree, x) \ | |
346 | do { \ | |
347 | if (rcu_rbtree_is_nil(rbtree, x)) \ | |
348 | break; \ | |
349 | assert(rbtree->comp(x->max_end, \ | |
350 | calculate_node_max_end(rbtree, x)) == 0); \ | |
351 | } while (0) | |
352 | ||
5d2c985d MD |
353 | #else /* DEBUG */ |
354 | static | |
355 | void show_tree(struct rcu_rbtree *rbtree) | |
356 | { | |
357 | } | |
66b64c35 MD |
358 | |
359 | static | |
360 | void check_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *x) | |
361 | { | |
362 | } | |
5d2c985d | 363 | #endif /* DEBUG */ |
dff86257 MD |
364 | |
365 | static | |
366 | struct rcu_rbtree_node *make_nil(struct rcu_rbtree *rbtree) | |
367 | { | |
368 | return &rbtree->nil_node; | |
369 | } | |
370 | ||
371 | /* | |
372 | * Iterative rbtree search. | |
373 | */ | |
00539351 | 374 | struct rcu_rbtree_node *rcu_rbtree_search(struct rcu_rbtree *rbtree, |
66b64c35 MD |
375 | struct rcu_rbtree_node *x, |
376 | void *point) | |
377 | { | |
378 | struct rcu_rbtree_node *xl; | |
379 | ||
380 | dbg_printf("searching point 0x%lx\n", (unsigned long) point); | |
381 | x = rcu_dereference(x); | |
382 | ||
383 | while (!rcu_rbtree_is_nil(rbtree, x)) { | |
384 | dbg_usleep(10); | |
385 | xl = rcu_dereference(x->_left); | |
386 | dbg_printf("search x %lx x_end %lx x_max_end %lx\n", (unsigned long) x->begin, | |
387 | (unsigned long) x->end, (unsigned long) x->max_end); | |
388 | dbg_printf("search xl %lx xl_end %lx xl_max_end %lx\n", (unsigned long) xl->begin, | |
389 | (unsigned long) xl->end, (unsigned long) xl->max_end); | |
390 | if (!rcu_rbtree_is_nil(rbtree, xl) | |
391 | && (rbtree->comp(xl->max_end, point) > 0)) { | |
392 | dbg_printf("go left\n"); | |
393 | x = xl; | |
3d8a234b | 394 | } else if (rbtree->comp(x->begin, point) <= 0 |
66b64c35 MD |
395 | && rbtree->comp(point, x->end) < 0) { |
396 | dbg_printf("got it!\n"); | |
397 | break; | |
398 | } else if (rbtree->comp(point, x->begin) > 0) { | |
399 | dbg_printf("go right\n"); | |
400 | x = rcu_dereference(x->_right); | |
401 | } else { | |
402 | dbg_printf("not found!\n"); | |
403 | x = make_nil(rbtree); | |
404 | } | |
405 | } | |
406 | if (rcu_rbtree_is_nil(rbtree, x)) | |
407 | dbg_printf("Reached bottom of tree.\n"); | |
408 | ||
409 | return x; | |
410 | } | |
411 | ||
412 | struct rcu_rbtree_node *rcu_rbtree_search_range(struct rcu_rbtree *rbtree, | |
413 | struct rcu_rbtree_node *x, | |
414 | void *begin, void *end) | |
415 | { | |
416 | struct rcu_rbtree_node *node; | |
417 | ||
418 | node = rcu_rbtree_search(rbtree, x, begin); | |
419 | if (rcu_rbtree_is_nil(rbtree, node)) | |
420 | return node; | |
421 | if (rbtree->comp(node->end, end) < 0) | |
422 | return NULL; /* High is outside lookup range */ | |
423 | return node; | |
424 | } | |
425 | ||
426 | /* | |
427 | * Search by exact range start value. | |
428 | */ | |
429 | struct rcu_rbtree_node *rcu_rbtree_search_begin_key(struct rcu_rbtree *rbtree, | |
dff86257 MD |
430 | struct rcu_rbtree_node *x, |
431 | void *k) | |
432 | { | |
433 | x = rcu_dereference(x); | |
ac5f3963 | 434 | int comp; |
dff86257 | 435 | |
3366b9c0 | 436 | while (!rcu_rbtree_is_nil(rbtree, x) && (comp = rbtree->comp(k, x->begin)) != 0) { |
9c161ee1 | 437 | dbg_usleep(10); |
ac5f3963 | 438 | if (comp < 0) |
dca45c9f | 439 | x = rcu_dereference(x->_left); |
dff86257 | 440 | else |
dca45c9f | 441 | x = rcu_dereference(x->_right); |
dff86257 MD |
442 | } |
443 | return x; | |
444 | } | |
445 | ||
230dd288 MD |
446 | static |
447 | struct rcu_rbtree_node *rcu_rbtree_min_dup_decay(struct rcu_rbtree *rbtree, | |
448 | struct rcu_rbtree_node *x, | |
449 | struct rcu_rbtree_node **zr) | |
450 | { | |
451 | struct rcu_rbtree_node *xl; | |
452 | ||
453 | x = rcu_dereference(x); | |
454 | ||
8ded5fe9 | 455 | if (rcu_rbtree_is_nil(rbtree, x)) { |
230dd288 MD |
456 | *zr = x; |
457 | return x; | |
458 | } else | |
459 | *zr = x = dup_decay_node(rbtree, x); | |
460 | ||
8ded5fe9 | 461 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 462 | x = dup_decay_node(rbtree, xl); |
7ba89e62 | 463 | set_parent(x, get_decay(get_parent(x)), get_pos(x)); |
dca45c9f | 464 | get_parent(x)->_left = get_decay(get_parent(x)->_left); |
230dd288 MD |
465 | } |
466 | return x; | |
467 | } | |
468 | ||
469 | static | |
470 | struct rcu_rbtree_node *rcu_rbtree_min_update_decay(struct rcu_rbtree *rbtree, | |
471 | struct rcu_rbtree_node *x) | |
472 | { | |
473 | struct rcu_rbtree_node *xl; | |
474 | ||
475 | x = rcu_dereference(x); | |
476 | ||
8ded5fe9 | 477 | if (rcu_rbtree_is_nil(rbtree, x)) |
230dd288 MD |
478 | return x; |
479 | else { | |
dca45c9f MD |
480 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
481 | get_pos(x->_right)); | |
482 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
483 | get_pos(x->_left)); | |
230dd288 MD |
484 | } |
485 | ||
8ded5fe9 | 486 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 487 | x = xl; |
dca45c9f MD |
488 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
489 | get_pos(x->_right)); | |
490 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
491 | get_pos(x->_left)); | |
230dd288 MD |
492 | } |
493 | return x; | |
494 | } | |
495 | ||
dff86257 MD |
496 | struct rcu_rbtree_node *rcu_rbtree_min(struct rcu_rbtree *rbtree, |
497 | struct rcu_rbtree_node *x) | |
498 | { | |
499 | struct rcu_rbtree_node *xl; | |
500 | ||
501 | x = rcu_dereference(x); | |
502 | ||
8ded5fe9 | 503 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
504 | return x; |
505 | ||
8ded5fe9 | 506 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
dff86257 MD |
507 | x = xl; |
508 | return x; | |
509 | } | |
510 | ||
511 | struct rcu_rbtree_node *rcu_rbtree_max(struct rcu_rbtree *rbtree, | |
512 | struct rcu_rbtree_node *x) | |
513 | { | |
514 | struct rcu_rbtree_node *xr; | |
515 | ||
516 | x = rcu_dereference(x); | |
517 | ||
8ded5fe9 | 518 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
519 | return x; |
520 | ||
8ded5fe9 | 521 | while (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 MD |
522 | x = xr; |
523 | return x; | |
524 | } | |
525 | ||
dff86257 | 526 | /* |
7ba89e62 MD |
527 | * RCU read lock must be held across the next/prev calls to ensure validity of |
528 | * the returned node. | |
dff86257 MD |
529 | */ |
530 | struct rcu_rbtree_node *rcu_rbtree_next(struct rcu_rbtree *rbtree, | |
531 | struct rcu_rbtree_node *x) | |
532 | { | |
269a9ef6 | 533 | struct rcu_rbtree_node *xr, *y; |
7ba89e62 | 534 | unsigned int x_pos; |
dff86257 MD |
535 | |
536 | x = rcu_dereference(x); | |
537 | ||
8ded5fe9 | 538 | if (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 | 539 | return rcu_rbtree_min(rbtree, xr); |
7ba89e62 | 540 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 541 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_RIGHT) { |
dff86257 | 542 | x = y; |
7ba89e62 | 543 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
544 | } |
545 | return y; | |
546 | } | |
547 | ||
548 | struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree *rbtree, | |
549 | struct rcu_rbtree_node *x) | |
550 | { | |
269a9ef6 | 551 | struct rcu_rbtree_node *xl, *y; |
7ba89e62 | 552 | unsigned int x_pos; |
dff86257 MD |
553 | |
554 | x = rcu_dereference(x); | |
555 | ||
8ded5fe9 | 556 | if (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
4aa30442 | 557 | return rcu_rbtree_max(rbtree, xl); |
7ba89e62 | 558 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 559 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_LEFT) { |
dff86257 | 560 | x = y; |
7ba89e62 | 561 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
562 | } |
563 | return y; | |
564 | } | |
565 | ||
7bc64d1d MD |
566 | /* |
567 | * "node" needs to be non-visible by readers. | |
568 | */ | |
569 | static | |
570 | void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, | |
fcb4eea8 | 571 | unsigned int copy_parents, struct rcu_rbtree_node *stop) |
7bc64d1d MD |
572 | { |
573 | struct rcu_rbtree_node *prev = NULL, *orig_node = node, *top; | |
574 | ||
575 | do { | |
576 | void *max_end; | |
577 | ||
fcb4eea8 | 578 | assert(node); |
7bc64d1d | 579 | assert(!rcu_rbtree_is_nil(rbtree, node)); |
4459c487 | 580 | |
66b64c35 MD |
581 | if (prev && copy_parents) { |
582 | node = dup_decay_node(rbtree, node); | |
583 | if (get_pos(prev) == IS_RIGHT) | |
584 | node->_right = prev; | |
585 | else | |
586 | node->_left = prev; | |
587 | set_parent(prev, node, get_pos(prev)); | |
588 | } | |
589 | ||
fda7316a | 590 | max_end = calculate_node_max_end(rbtree, node); |
66b64c35 MD |
591 | /* |
592 | * Compare the node max_end keys to make sure we replace | |
593 | * references to a key belonging to a node we remove | |
594 | * from the tree. Otherwise we would still be using this | |
595 | * pointer as an invalid reference after garbage | |
596 | * collection of the node and of its associated | |
597 | * begin/end pointers. | |
598 | */ | |
599 | if (max_end != node->max_end) { | |
7bc64d1d MD |
600 | node->max_end = max_end; |
601 | } else { | |
7bc64d1d MD |
602 | top = get_parent(node); |
603 | cmm_smp_wmb(); /* write into node before publish */ | |
604 | /* make new branch visible to readers */ | |
605 | if (rcu_rbtree_is_nil(rbtree, top)) | |
606 | _CMM_STORE_SHARED(rbtree->root, node); | |
607 | if (get_pos(node) == IS_LEFT) | |
608 | _CMM_STORE_SHARED(top->_left, node); | |
609 | else | |
610 | _CMM_STORE_SHARED(top->_right, node); | |
611 | goto end; | |
612 | } | |
fcb4eea8 MD |
613 | |
614 | /* Check for propagation stop */ | |
615 | if (node == stop) | |
616 | return; | |
617 | ||
7bc64d1d | 618 | prev = node; |
fcb4eea8 MD |
619 | node = get_parent(node); |
620 | } while (!rcu_rbtree_is_nil(rbtree, node)); | |
7bc64d1d MD |
621 | |
622 | top = node; /* nil */ | |
623 | cmm_smp_wmb(); /* write into node before publish */ | |
624 | /* make new branch visible to readers */ | |
625 | _CMM_STORE_SHARED(rbtree->root, prev); | |
626 | ||
627 | end: | |
fcb4eea8 MD |
628 | if (!copy_parents) |
629 | return; | |
7bc64d1d MD |
630 | /* update children */ |
631 | node = orig_node; | |
632 | do { | |
633 | assert(!rcu_rbtree_is_nil(rbtree, node)); | |
634 | set_parent(node->_left, get_decay(get_parent(node->_left)), IS_LEFT); | |
635 | set_parent(node->_right, get_decay(get_parent(node->_right)), IS_RIGHT); | |
636 | } while ((node = get_parent(node)) != top); | |
637 | } | |
638 | ||
dff86257 MD |
639 | /* |
640 | * We have to ensure these assumptions are correct for prev/next | |
641 | * traversal: | |
642 | * | |
643 | * with x being a right child, the assumption that: | |
dca45c9f | 644 | * get_parent(x)->_right == x |
dff86257 | 645 | * or if x is a left child, the assumption that: |
dca45c9f | 646 | * get_parent(x)->_left == x |
dff86257 MD |
647 | * |
648 | * This explains why we have to allocate a vc copy of the node for left_rotate, | |
649 | * right_rotate and transplant operations. | |
650 | * | |
651 | * We always ensure that the right/left child and correct parent is set in the | |
652 | * node copies *before* we reparent the children and make the upper-level point | |
653 | * to the copy. | |
654 | */ | |
655 | ||
656 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
657 | /* Should be eventually followed by a cmm_smp_wmc() */ | |
dff86257 | 658 | |
dbe4ae98 MD |
659 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_LEFT |
660 | ||
dff86257 | 661 | static |
269a9ef6 MD |
662 | void left_rotate(struct rcu_rbtree *rbtree, |
663 | struct rcu_rbtree_node *x) | |
dff86257 | 664 | { |
a84e8c8e | 665 | struct rcu_rbtree_node *y, *y_left; |
dff86257 | 666 | |
66b64c35 MD |
667 | dbg_printf("left rotate %lx\n", (unsigned long) x->begin); |
668 | ||
dca45c9f MD |
669 | y = x->_right; |
670 | y_left = y->_left; | |
269a9ef6 MD |
671 | |
672 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
673 | x = dup_decay_node(rbtree, x); |
674 | y = dup_decay_node(rbtree, y); | |
675 | y_left = dup_decay_node(rbtree, y_left); | |
269a9ef6 | 676 | |
66b64c35 MD |
677 | check_max_end(rbtree, get_parent(x)); |
678 | check_max_end(rbtree, x); | |
679 | check_max_end(rbtree, y); | |
680 | ||
676dd8b6 | 681 | /* Internal node modifications */ |
7ba89e62 MD |
682 | set_parent(y, get_parent(x), get_pos(x)); |
683 | set_parent(x, y, IS_LEFT); | |
a84e8c8e MD |
684 | set_left(rbtree, y, x); |
685 | set_right(rbtree, x, y_left); | |
dca45c9f | 686 | |
8ded5fe9 | 687 | if (!rcu_rbtree_is_nil(rbtree, y_left)) |
7ba89e62 | 688 | set_parent(y_left, x, IS_RIGHT); |
676dd8b6 | 689 | |
fda7316a MD |
690 | /* |
691 | * We only changed the relative position of x and y wrt their | |
692 | * children, and reparented y (but are keeping the same nodes in | |
693 | * place, so its parent does not need to have end value | |
694 | * recalculated). | |
695 | */ | |
696 | x->max_end = calculate_node_max_end(rbtree, x); | |
697 | y->max_end = calculate_node_max_end(rbtree, y); | |
698 | ||
676dd8b6 MD |
699 | cmm_smp_wmb(); /* write into node before publish */ |
700 | ||
701 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
702 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
703 | _CMM_STORE_SHARED(rbtree->root, y); | |
704 | else if (get_pos(y) == IS_LEFT) | |
705 | _CMM_STORE_SHARED(get_parent(y)->_left, y); | |
676dd8b6 | 706 | else |
a84e8c8e | 707 | _CMM_STORE_SHARED(get_parent(y)->_right, y); |
676dd8b6 | 708 | |
dbe4ae98 | 709 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
710 | set_parent(x->_left, get_decay(get_parent(x->_left)), |
711 | get_pos(x->_left)); | |
712 | set_parent(y->_right, get_decay(get_parent(y->_right)), | |
713 | get_pos(y->_right)); | |
8ded5fe9 | 714 | if (!rcu_rbtree_is_nil(rbtree, y_left)) { |
dca45c9f MD |
715 | set_parent(y_left->_right, |
716 | get_decay(get_parent(y_left->_right)), | |
717 | get_pos(y_left->_right)); | |
718 | set_parent(y_left->_left, | |
719 | get_decay(get_parent(y_left->_left)), | |
720 | get_pos(y_left->_left)); | |
dbe4ae98 | 721 | } |
269a9ef6 MD |
722 | |
723 | /* Sanity checks */ | |
dca45c9f MD |
724 | assert(y == rbtree->root || get_parent(y)->_left == y |
725 | || get_parent(y)->_right == y); | |
726 | assert(x == rbtree->root || get_parent(x)->_left == x | |
727 | || get_parent(x)->_right == x); | |
8ded5fe9 MD |
728 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); |
729 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); | |
730 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
731 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
269a9ef6 MD |
732 | assert(!is_decay(rbtree->root)); |
733 | assert(!is_decay(x)); | |
734 | assert(!is_decay(y)); | |
dca45c9f MD |
735 | assert(!is_decay(x->_right)); |
736 | assert(!is_decay(x->_left)); | |
737 | assert(!is_decay(y->_right)); | |
738 | assert(!is_decay(y->_left)); | |
66b64c35 MD |
739 | check_max_end(rbtree, get_parent(y)); |
740 | check_max_end(rbtree, x); | |
741 | check_max_end(rbtree, y); | |
dff86257 MD |
742 | } |
743 | ||
dbe4ae98 MD |
744 | #else |
745 | ||
746 | /* non-rcu version */ | |
747 | static | |
748 | void left_rotate(struct rcu_rbtree *rbtree, | |
749 | struct rcu_rbtree_node *x) | |
750 | { | |
751 | struct rcu_rbtree_node *y; | |
752 | ||
230dd288 | 753 | lock_test_mutex(); |
dca45c9f MD |
754 | y = x->_right; |
755 | x->_right = y->_left; | |
8ded5fe9 | 756 | if (!rcu_rbtree_is_nil(rbtree, y->_left)) |
dca45c9f | 757 | set_parent(y->_left, x, IS_RIGHT); |
7ba89e62 | 758 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 759 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
dbe4ae98 | 760 | rbtree->root = y; |
dca45c9f MD |
761 | else if (x == get_parent(x)->_left) { |
762 | get_parent(x)->_left = y; | |
dbe4ae98 | 763 | } else { |
dca45c9f | 764 | get_parent(x)->_right = y; |
dbe4ae98 | 765 | } |
dca45c9f | 766 | y->_left = x; |
7ba89e62 | 767 | set_parent(x, y, IS_LEFT); |
230dd288 | 768 | unlock_test_mutex(); |
dbe4ae98 MD |
769 | } |
770 | ||
771 | #endif | |
772 | ||
773 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
dff86257 | 774 | static |
269a9ef6 MD |
775 | void right_rotate(struct rcu_rbtree *rbtree, |
776 | struct rcu_rbtree_node *x) | |
dff86257 | 777 | { |
a84e8c8e | 778 | struct rcu_rbtree_node *y, *y_right; |
dff86257 | 779 | |
66b64c35 MD |
780 | dbg_printf("right rotate %lx\n", (unsigned long) x->begin); |
781 | ||
dca45c9f MD |
782 | y = x->_left; |
783 | y_right = y->_right; | |
269a9ef6 MD |
784 | |
785 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
786 | x = dup_decay_node(rbtree, x); |
787 | y = dup_decay_node(rbtree, y); | |
788 | y_right = dup_decay_node(rbtree, y_right); | |
269a9ef6 | 789 | |
66b64c35 MD |
790 | check_max_end(rbtree, get_parent(x)); |
791 | check_max_end(rbtree, x); | |
792 | check_max_end(rbtree, y); | |
793 | ||
676dd8b6 | 794 | /* Internal node modifications */ |
7ba89e62 MD |
795 | set_parent(y, get_parent(x), get_pos(x)); |
796 | set_parent(x, y, IS_RIGHT); | |
a84e8c8e MD |
797 | set_right(rbtree, y, x); |
798 | set_left(rbtree, x, y_right); | |
dca45c9f | 799 | |
8ded5fe9 | 800 | if (!rcu_rbtree_is_nil(rbtree, y_right)) |
7ba89e62 | 801 | set_parent(y_right, x, IS_LEFT); |
676dd8b6 | 802 | |
fda7316a MD |
803 | /* |
804 | * We only changed the relative position of x and y wrt their | |
805 | * children, and reparented y (but are keeping the same nodes in | |
806 | * place, so its parent does not need to have end value | |
807 | * recalculated). | |
808 | */ | |
809 | x->max_end = calculate_node_max_end(rbtree, x); | |
810 | y->max_end = calculate_node_max_end(rbtree, y); | |
811 | ||
676dd8b6 MD |
812 | cmm_smp_wmb(); /* write into node before publish */ |
813 | ||
814 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
815 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
816 | _CMM_STORE_SHARED(rbtree->root, y); | |
817 | else if (get_pos(y) == IS_RIGHT) | |
818 | _CMM_STORE_SHARED(get_parent(y)->_right, y); | |
676dd8b6 | 819 | else |
a84e8c8e | 820 | _CMM_STORE_SHARED(get_parent(y)->_left, y); |
676dd8b6 | 821 | |
dbe4ae98 | 822 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
823 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
824 | get_pos(x->_right)); | |
825 | set_parent(y->_left, get_decay(get_parent(y->_left)), | |
826 | get_pos(y->_left)); | |
8ded5fe9 | 827 | if (!rcu_rbtree_is_nil(rbtree, y_right)) { |
dca45c9f MD |
828 | set_parent(y_right->_left, |
829 | get_decay(get_parent(y_right->_left)), | |
830 | get_pos(y_right->_left)); | |
831 | set_parent(y_right->_right, | |
832 | get_decay(get_parent(y_right->_right)), | |
833 | get_pos(y_right->_right)); | |
dbe4ae98 | 834 | } |
269a9ef6 MD |
835 | |
836 | /* Sanity checks */ | |
dca45c9f MD |
837 | assert(y == rbtree->root || get_parent(y)->_right == y |
838 | || get_parent(y)->_left == y); | |
839 | assert(x == rbtree->root || get_parent(x)->_right == x | |
840 | || get_parent(x)->_left == x); | |
8ded5fe9 MD |
841 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); |
842 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); | |
843 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
844 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
269a9ef6 MD |
845 | assert(!is_decay(rbtree->root)); |
846 | assert(!is_decay(x)); | |
847 | assert(!is_decay(y)); | |
dca45c9f MD |
848 | assert(!is_decay(x->_left)); |
849 | assert(!is_decay(x->_right)); | |
850 | assert(!is_decay(y->_left)); | |
851 | assert(!is_decay(y->_right)); | |
66b64c35 MD |
852 | check_max_end(rbtree, x); |
853 | check_max_end(rbtree, y); | |
854 | check_max_end(rbtree, get_parent(y)); | |
dff86257 MD |
855 | } |
856 | ||
6daf6090 MD |
857 | #else |
858 | ||
dbe4ae98 | 859 | /* non-rcu version */ |
6daf6090 MD |
860 | static |
861 | void right_rotate(struct rcu_rbtree *rbtree, | |
862 | struct rcu_rbtree_node *x) | |
863 | { | |
864 | struct rcu_rbtree_node *y; | |
865 | ||
230dd288 | 866 | lock_test_mutex(); |
dca45c9f MD |
867 | y = x->_left; |
868 | x->_left = y->_right; | |
8ded5fe9 | 869 | if (!rcu_rbtree_is_nil(rbtree, y->_right)) |
dca45c9f | 870 | set_parent(y->_right, x, IS_LEFT); |
7ba89e62 | 871 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 872 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
6daf6090 | 873 | rbtree->root = y; |
dca45c9f MD |
874 | else if (x == get_parent(x)->_right) { |
875 | get_parent(x)->_right = y; | |
6daf6090 | 876 | } else { |
dca45c9f | 877 | get_parent(x)->_left = y; |
6daf6090 | 878 | } |
dca45c9f | 879 | y->_right = x; |
7ba89e62 | 880 | set_parent(x, y, IS_RIGHT); |
230dd288 | 881 | unlock_test_mutex(); |
6daf6090 MD |
882 | } |
883 | ||
884 | #endif | |
885 | ||
dff86257 MD |
886 | static void rcu_rbtree_insert_fixup(struct rcu_rbtree *rbtree, |
887 | struct rcu_rbtree_node *z) | |
888 | { | |
889 | struct rcu_rbtree_node *y; | |
890 | ||
3366b9c0 | 891 | dbg_printf("insert fixup %p\n", z->begin); |
269a9ef6 | 892 | assert(!is_decay(rbtree->root)); |
dff86257 | 893 | |
7ba89e62 | 894 | while (get_parent(z)->color == COLOR_RED) { |
dca45c9f MD |
895 | if (get_parent(z) == get_parent(get_parent(z))->_left) { |
896 | y = get_parent(get_parent(z))->_right; | |
dff86257 | 897 | if (y->color == COLOR_RED) { |
7ba89e62 | 898 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 899 | y->color = COLOR_BLACK; |
7ba89e62 MD |
900 | get_parent(get_parent(z))->color = COLOR_RED; |
901 | z = get_parent(get_parent(z)); | |
dff86257 | 902 | } else { |
dca45c9f | 903 | if (z == get_parent(z)->_right) { |
7ba89e62 | 904 | z = get_parent(z); |
dff86257 | 905 | left_rotate(rbtree, z); |
269a9ef6 MD |
906 | z = get_decay(z); |
907 | assert(!is_decay(rbtree->root)); | |
dff86257 | 908 | } |
7ba89e62 MD |
909 | get_parent(z)->color = COLOR_BLACK; |
910 | get_parent(get_parent(z))->color = COLOR_RED; | |
269a9ef6 | 911 | assert(!is_decay(z)); |
7ba89e62 MD |
912 | assert(!is_decay(get_parent(z))); |
913 | assert(!is_decay(get_parent(get_parent(z)))); | |
914 | right_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
915 | assert(!is_decay(z)); |
916 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
917 | } |
918 | } else { | |
dca45c9f | 919 | y = get_parent(get_parent(z))->_left; |
dff86257 | 920 | if (y->color == COLOR_RED) { |
7ba89e62 | 921 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 922 | y->color = COLOR_BLACK; |
7ba89e62 MD |
923 | get_parent(get_parent(z))->color = COLOR_RED; |
924 | z = get_parent(get_parent(z)); | |
dff86257 | 925 | } else { |
dca45c9f | 926 | if (z == get_parent(z)->_left) { |
7ba89e62 | 927 | z = get_parent(z); |
dff86257 | 928 | right_rotate(rbtree, z); |
269a9ef6 MD |
929 | z = get_decay(z); |
930 | assert(!is_decay(rbtree->root)); | |
dff86257 | 931 | } |
7ba89e62 MD |
932 | get_parent(z)->color = COLOR_BLACK; |
933 | get_parent(get_parent(z))->color = COLOR_RED; | |
934 | left_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
935 | assert(!is_decay(z)); |
936 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
937 | } |
938 | } | |
939 | } | |
940 | rbtree->root->color = COLOR_BLACK; | |
941 | } | |
942 | ||
943 | /* | |
944 | * rcu_rbtree_insert - Insert a node in the RCU rbtree | |
945 | * | |
946 | * Returns 0 on success, or < 0 on error. | |
947 | */ | |
948 | int rcu_rbtree_insert(struct rcu_rbtree *rbtree, | |
3c672595 | 949 | void *begin, void *end) |
dff86257 | 950 | { |
3c672595 MD |
951 | struct rcu_rbtree_node *x, *y, *z; |
952 | ||
8f354bc4 MD |
953 | z = _rcu_rbtree_alloc_node(rbtree); |
954 | if (!z) | |
955 | return -ENOMEM; | |
3c672595 MD |
956 | z->begin = begin; |
957 | z->end = end; | |
dff86257 | 958 | |
3366b9c0 | 959 | dbg_printf("insert %p\n", z->begin); |
269a9ef6 | 960 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
961 | |
962 | y = make_nil(rbtree); | |
dff86257 | 963 | x = rbtree->root; |
8ded5fe9 | 964 | while (!rcu_rbtree_is_nil(rbtree, x)) { |
dff86257 | 965 | y = x; |
3366b9c0 | 966 | if (rbtree->comp(z->begin, x->begin) < 0) |
dca45c9f | 967 | x = x->_left; |
dff86257 | 968 | else |
dca45c9f | 969 | x = x->_right; |
dff86257 MD |
970 | } |
971 | ||
dca45c9f MD |
972 | z->_left = make_nil(rbtree); |
973 | z->_right = make_nil(rbtree); | |
dff86257 | 974 | z->color = COLOR_RED; |
269a9ef6 | 975 | z->decay_next = NULL; |
55b5e812 | 976 | z->max_end = z->end; |
3c672595 | 977 | z->rbtree = rbtree; |
dff86257 | 978 | |
8ded5fe9 | 979 | if (rcu_rbtree_is_nil(rbtree, y)) { |
7bc64d1d | 980 | set_parent(z, y, IS_RIGHT); /* pos arbitrary for root node */ |
0bd215cc MD |
981 | /* |
982 | * Order stores to z (children/parents) before stores | |
983 | * that will make it visible to the rest of the tree. | |
984 | */ | |
985 | cmm_smp_wmb(); | |
dff86257 | 986 | _CMM_STORE_SHARED(rbtree->root, z); |
3366b9c0 | 987 | } else if (rbtree->comp(z->begin, y->begin) < 0) { |
7bc64d1d MD |
988 | y = dup_decay_node(rbtree, y); |
989 | set_parent(z, y, IS_LEFT); | |
990 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 991 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 992 | else |
a84e8c8e | 993 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 994 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 995 | } else { |
7bc64d1d MD |
996 | y = dup_decay_node(rbtree, y); |
997 | set_parent(z, y, IS_RIGHT); | |
998 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 999 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 1000 | else |
a84e8c8e | 1001 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 1002 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 1003 | } |
dff86257 MD |
1004 | rcu_rbtree_insert_fixup(rbtree, z); |
1005 | /* | |
1006 | * Make sure to commit all _CMM_STORE_SHARED() for non-coherent caches. | |
1007 | */ | |
1008 | cmm_smp_wmc(); | |
1009 | show_tree(rbtree); | |
66b64c35 MD |
1010 | check_max_end(rbtree, z); |
1011 | check_max_end(rbtree, y); | |
dff86257 MD |
1012 | |
1013 | return 0; | |
1014 | } | |
1015 | ||
1016 | /* | |
1017 | * Transplant v into u position. | |
dff86257 | 1018 | */ |
6daf6090 MD |
1019 | |
1020 | #ifdef RBTREE_RCU_SUPPORT_TRANSPLANT | |
1021 | ||
269a9ef6 MD |
1022 | static |
1023 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1024 | struct rcu_rbtree_node *u, | |
dca45c9f | 1025 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1026 | unsigned int copy_parents, |
1027 | struct rcu_rbtree_node *stop) | |
dff86257 | 1028 | { |
3366b9c0 | 1029 | dbg_printf("transplant %p\n", v->begin); |
dff86257 | 1030 | |
8ded5fe9 | 1031 | if (!rcu_rbtree_is_nil(rbtree, v)) |
dbe4ae98 | 1032 | v = dup_decay_node(rbtree, v); |
c479601c | 1033 | |
8ded5fe9 | 1034 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
7ba89e62 MD |
1035 | /* pos is arbitrary for root node */ |
1036 | set_parent(v, get_parent(u), IS_RIGHT); | |
c479601c MD |
1037 | cmm_smp_wmb(); /* write into node before publish */ |
1038 | _CMM_STORE_SHARED(rbtree->root, v); | |
dff86257 | 1039 | } else { |
fcb4eea8 MD |
1040 | struct rcu_rbtree_node *vp; |
1041 | ||
1042 | vp = get_parent(u); | |
1043 | if (copy_parents) | |
1044 | vp = dup_decay_node(rbtree, vp); | |
1045 | set_parent(v, vp, get_pos(u)); | |
1046 | if (get_pos(v) == IS_LEFT) | |
1047 | _CMM_STORE_SHARED(vp->_left, v); | |
806967f3 | 1048 | else |
fcb4eea8 MD |
1049 | _CMM_STORE_SHARED(vp->_right, v); |
1050 | populate_node_end(rbtree, vp, copy_parents, stop); | |
66b64c35 | 1051 | check_max_end(rbtree, vp); |
c479601c | 1052 | } |
806967f3 | 1053 | |
dbe4ae98 | 1054 | /* Point children to new copy (parent only used by updates/next/prev) */ |
8ded5fe9 | 1055 | if (!rcu_rbtree_is_nil(rbtree, v)) { |
dca45c9f MD |
1056 | set_parent(v->_right, get_decay(get_parent(v->_right)), |
1057 | get_pos(v->_right)); | |
1058 | set_parent(v->_left, get_decay(get_parent(v->_left)), | |
1059 | get_pos(v->_left)); | |
dff86257 | 1060 | } |
269a9ef6 | 1061 | assert(!is_decay(rbtree->root)); |
66b64c35 | 1062 | check_max_end(rbtree, v); |
dff86257 MD |
1063 | } |
1064 | ||
6daf6090 MD |
1065 | #else |
1066 | ||
1067 | /* Non-RCU version */ | |
1068 | static | |
1069 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1070 | struct rcu_rbtree_node *u, | |
dca45c9f | 1071 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1072 | unsigned int copy_parents, |
1073 | struct rcu_rbtree_node *stop) | |
6daf6090 | 1074 | { |
3366b9c0 | 1075 | dbg_printf("transplant %p\n", v->begin); |
6daf6090 | 1076 | |
230dd288 | 1077 | lock_test_mutex(); |
8ded5fe9 | 1078 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) |
6daf6090 | 1079 | rbtree->root = v; |
dca45c9f MD |
1080 | else if (u == get_parent(u)->_left) |
1081 | get_parent(u)->_left = v; | |
7ba89e62 | 1082 | else |
dca45c9f | 1083 | get_parent(u)->_right = v; |
7ba89e62 | 1084 | set_parent(v, get_parent(u), get_pos(u)); |
230dd288 | 1085 | unlock_test_mutex(); |
6daf6090 MD |
1086 | } |
1087 | ||
1088 | #endif | |
1089 | ||
dff86257 MD |
1090 | static void rcu_rbtree_remove_fixup(struct rcu_rbtree *rbtree, |
1091 | struct rcu_rbtree_node *x) | |
1092 | { | |
3366b9c0 | 1093 | dbg_printf("remove fixup %p\n", x->begin); |
dff86257 MD |
1094 | |
1095 | while (x != rbtree->root && x->color == COLOR_BLACK) { | |
7ba89e62 | 1096 | assert(!is_decay(get_parent(x))); |
dca45c9f MD |
1097 | assert(!is_decay(get_parent(x)->_left)); |
1098 | if (x == get_parent(x)->_left) { | |
269a9ef6 | 1099 | struct rcu_rbtree_node *w; |
dff86257 | 1100 | |
dca45c9f | 1101 | w = get_parent(x)->_right; |
dff86257 MD |
1102 | |
1103 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1104 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1105 | get_parent(x)->color = COLOR_RED; |
1106 | left_rotate(rbtree, get_parent(x)); | |
269a9ef6 MD |
1107 | x = get_decay(x); |
1108 | assert(!is_decay(rbtree->root)); | |
dca45c9f | 1109 | w = get_parent(x)->_right; |
dff86257 | 1110 | } |
dca45c9f MD |
1111 | if (w->_left->color == COLOR_BLACK |
1112 | && w->_right->color == COLOR_BLACK) { | |
dff86257 | 1113 | w->color = COLOR_RED; |
7ba89e62 | 1114 | x = get_parent(x); |
c479601c MD |
1115 | assert(!is_decay(rbtree->root)); |
1116 | assert(!is_decay(x)); | |
dff86257 | 1117 | } else { |
dca45c9f MD |
1118 | if (w->_right->color == COLOR_BLACK) { |
1119 | w->_left->color = COLOR_BLACK; | |
dff86257 MD |
1120 | w->color = COLOR_RED; |
1121 | right_rotate(rbtree, w); | |
c479601c | 1122 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1123 | x = get_decay(x); |
dca45c9f | 1124 | w = get_parent(x)->_right; |
dff86257 | 1125 | } |
7ba89e62 MD |
1126 | w->color = get_parent(x)->color; |
1127 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1128 | w->_right->color = COLOR_BLACK; |
7ba89e62 | 1129 | left_rotate(rbtree, get_parent(x)); |
269a9ef6 | 1130 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1131 | x = rbtree->root; |
1132 | } | |
1133 | } else { | |
269a9ef6 | 1134 | struct rcu_rbtree_node *w; |
dff86257 | 1135 | |
dca45c9f | 1136 | w = get_parent(x)->_left; |
dff86257 MD |
1137 | |
1138 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1139 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1140 | get_parent(x)->color = COLOR_RED; |
1141 | right_rotate(rbtree, get_parent(x)); | |
c479601c | 1142 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1143 | x = get_decay(x); |
dca45c9f | 1144 | w = get_parent(x)->_left; |
dff86257 | 1145 | } |
dca45c9f MD |
1146 | if (w->_right->color == COLOR_BLACK |
1147 | && w->_left->color == COLOR_BLACK) { | |
dff86257 | 1148 | w->color = COLOR_RED; |
7ba89e62 | 1149 | x = get_parent(x); |
c479601c MD |
1150 | assert(!is_decay(rbtree->root)); |
1151 | assert(!is_decay(x)); | |
dff86257 | 1152 | } else { |
dca45c9f MD |
1153 | if (w->_left->color == COLOR_BLACK) { |
1154 | w->_right->color = COLOR_BLACK; | |
dff86257 MD |
1155 | w->color = COLOR_RED; |
1156 | left_rotate(rbtree, w); | |
269a9ef6 MD |
1157 | assert(!is_decay(rbtree->root)); |
1158 | x = get_decay(x); | |
dca45c9f | 1159 | w = get_parent(x)->_left; |
dff86257 | 1160 | } |
7ba89e62 MD |
1161 | w->color = get_parent(x)->color; |
1162 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1163 | w->_left->color = COLOR_BLACK; |
7ba89e62 | 1164 | right_rotate(rbtree, get_parent(x)); |
c479601c | 1165 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1166 | x = rbtree->root; |
1167 | } | |
1168 | } | |
1169 | } | |
1170 | x->color = COLOR_BLACK; | |
1171 | } | |
1172 | ||
1173 | /* | |
269a9ef6 MD |
1174 | * Delete z. All non-copied children left/right positions are unchanged. |
1175 | */ | |
1176 | static | |
1177 | void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, | |
1178 | struct rcu_rbtree_node *z, | |
1179 | struct rcu_rbtree_node *y) | |
dff86257 | 1180 | { |
a84e8c8e | 1181 | struct rcu_rbtree_node *x; |
dff86257 | 1182 | |
3366b9c0 | 1183 | dbg_printf("remove nonil %p\n", z->begin); |
dff86257 MD |
1184 | show_tree(rbtree); |
1185 | ||
c479601c MD |
1186 | assert(!is_decay(z)); |
1187 | assert(!is_decay(y)); | |
dca45c9f | 1188 | assert(!is_decay(y->_right)); |
7ba89e62 | 1189 | assert(!is_decay(get_parent(y))); |
dca45c9f | 1190 | x = y->_right; |
c479601c | 1191 | assert(!is_decay(x)); |
7ba89e62 | 1192 | if (get_parent(y) == z) { |
230dd288 | 1193 | y = dup_decay_node(rbtree, y); |
7ba89e62 | 1194 | set_parent(x, y, get_pos(x)); /* parent for nil */ |
66b64c35 | 1195 | /* y is z's right node */ |
a84e8c8e | 1196 | set_left(rbtree, y, z->_left); |
66b64c35 | 1197 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1198 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 MD |
1199 | } else { |
1200 | struct rcu_rbtree_node *oy_right, *z_right; | |
1201 | ||
1202 | /* | |
1203 | * Need to make sure y is always visible by readers. | |
1204 | */ | |
dca45c9f | 1205 | y = rcu_rbtree_min_dup_decay(rbtree, z->_right, &z_right); |
269a9ef6 MD |
1206 | assert(!is_decay(y)); |
1207 | assert(!is_decay(z)); | |
dca45c9f MD |
1208 | oy_right = y->_right; |
1209 | ||
1210 | /* | |
3366b9c0 | 1211 | * The max child begin of z_right does not change, because |
dca45c9f MD |
1212 | * we're only changing its left children. |
1213 | */ | |
1214 | y->_right = z_right; | |
1215 | set_parent(y->_right, y, IS_RIGHT); | |
dca45c9f MD |
1216 | assert(!is_decay(z->_left)); |
1217 | y->_left = z->_left; | |
230dd288 | 1218 | assert(!is_decay(oy_right)); |
dca45c9f MD |
1219 | /* |
1220 | * Transplant of oy_right to old y's location will only | |
fcb4eea8 | 1221 | * trigger a "end" value update of the already copied branch |
dca45c9f MD |
1222 | * (which is not visible yet). We are transplanting |
1223 | * oy_right as a left child of old y's parent, so the | |
1224 | * min values update propagated upward necessarily stops | |
1225 | * at z_right. | |
1226 | */ | |
fcb4eea8 | 1227 | rcu_rbtree_transplant(rbtree, y, oy_right, 0, y); |
66b64c35 | 1228 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1229 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 | 1230 | /* Update children */ |
dca45c9f | 1231 | (void) rcu_rbtree_min_update_decay(rbtree, y->_right); |
dff86257 | 1232 | } |
c479601c | 1233 | y = get_decay(y); |
269a9ef6 | 1234 | assert(!is_decay(z)); |
dca45c9f | 1235 | assert(!is_decay(z->_left)); |
dff86257 | 1236 | y->color = z->color; |
dca45c9f MD |
1237 | set_parent(y->_left, y, IS_LEFT); |
1238 | set_parent(y->_right, get_decay(get_parent(y->_right)), IS_RIGHT); | |
1239 | assert(!is_decay(y->_left)); | |
1240 | assert(!is_decay(y->_right)); | |
dff86257 MD |
1241 | } |
1242 | ||
1243 | int rcu_rbtree_remove(struct rcu_rbtree *rbtree, | |
1244 | struct rcu_rbtree_node *z) | |
1245 | { | |
1246 | struct rcu_rbtree_node *x, *y; | |
1247 | unsigned int y_original_color; | |
1248 | ||
269a9ef6 | 1249 | assert(!is_decay(rbtree->root)); |
3366b9c0 | 1250 | dbg_printf("remove %p\n", z->begin); |
dff86257 MD |
1251 | show_tree(rbtree); |
1252 | ||
c479601c | 1253 | assert(!is_decay(z)); |
dff86257 MD |
1254 | y = z; |
1255 | y_original_color = y->color; | |
1256 | ||
8ded5fe9 | 1257 | if (rcu_rbtree_is_nil(rbtree, z->_left)) { |
fcb4eea8 | 1258 | rcu_rbtree_transplant(rbtree, z, z->_right, 1, NULL); |
269a9ef6 | 1259 | assert(!is_decay(z)); |
dca45c9f | 1260 | x = get_decay(z->_right); |
dff86257 | 1261 | show_tree(rbtree); |
8ded5fe9 | 1262 | } else if (rcu_rbtree_is_nil(rbtree, z->_right)) { |
fcb4eea8 | 1263 | rcu_rbtree_transplant(rbtree, z, z->_left, 1, NULL); |
269a9ef6 | 1264 | assert(!is_decay(z)); |
dca45c9f | 1265 | x = get_decay(z->_left); |
dff86257 MD |
1266 | show_tree(rbtree); |
1267 | } else { | |
dca45c9f | 1268 | y = rcu_rbtree_min(rbtree, z->_right); |
c479601c | 1269 | assert(!is_decay(y)); |
dff86257 | 1270 | y_original_color = y->color; |
dca45c9f | 1271 | x = y->_right; |
269a9ef6 | 1272 | rcu_rbtree_remove_nonil(rbtree, z, y); |
6daf6090 | 1273 | x = get_decay(x); |
dff86257 MD |
1274 | show_tree(rbtree); |
1275 | } | |
1276 | if (y_original_color == COLOR_BLACK) | |
1277 | rcu_rbtree_remove_fixup(rbtree, x); | |
1278 | show_tree(rbtree); | |
66b64c35 MD |
1279 | check_max_end(rbtree, x); |
1280 | check_max_end(rbtree, get_decay(y)); | |
dff86257 MD |
1281 | /* |
1282 | * Commit all _CMM_STORE_SHARED(). | |
1283 | */ | |
1284 | cmm_smp_wmc(); | |
1cdd423d | 1285 | rbtree->call_rcu(&z->head, _rcu_rbtree_free_node); |
dff86257 MD |
1286 | |
1287 | return 0; | |
1288 | } |