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 | |
24b9b19b MD |
164 | #ifdef RBTREE_RCU_SUPPORT |
165 | #define c_rcu_dereference(x) rcu_dereference(x) | |
166 | #else | |
167 | #define c_rcu_dereference(x) (x) | |
168 | #endif | |
169 | ||
1444707c MD |
170 | /* |
171 | * Add internal mutex locking within the RBTree, for debugging. Enable this | |
172 | * define and add mutexes to RCU readers to debug races with with rotation or | |
173 | * transplant. | |
174 | */ | |
175 | /* #define RBTREE_INTERNAL_LOCKING */ | |
176 | ||
177 | #ifdef RBTREE_INTERNAL_LOCKING | |
230dd288 MD |
178 | static pthread_mutex_t test_mutex = PTHREAD_MUTEX_INITIALIZER; |
179 | static pthread_mutex_t outer_mutex = PTHREAD_MUTEX_INITIALIZER; | |
180 | ||
181 | static | |
182 | void lock_outer_mutex(void) | |
183 | { | |
184 | pthread_mutex_lock(&outer_mutex); | |
185 | } | |
186 | ||
187 | static | |
188 | void unlock_outer_mutex(void) | |
189 | { | |
190 | pthread_mutex_unlock(&outer_mutex); | |
191 | } | |
192 | ||
193 | static | |
194 | void lock_test_mutex(void) | |
195 | { | |
196 | pthread_mutex_lock(&test_mutex); | |
197 | } | |
198 | ||
199 | static | |
200 | void unlock_test_mutex(void) | |
201 | { | |
202 | pthread_mutex_unlock(&test_mutex); | |
203 | } | |
1444707c MD |
204 | #else |
205 | static | |
206 | void lock_outer_mutex(void) | |
207 | { | |
208 | } | |
209 | ||
210 | static | |
211 | void unlock_outer_mutex(void) | |
212 | { | |
213 | } | |
214 | ||
215 | static | |
216 | void lock_test_mutex(void) | |
217 | { | |
218 | } | |
219 | ||
220 | static | |
221 | void unlock_test_mutex(void) | |
222 | { | |
223 | } | |
230dd288 MD |
224 | #endif |
225 | ||
7ba89e62 MD |
226 | static |
227 | void set_parent(struct rcu_rbtree_node *node, | |
228 | struct rcu_rbtree_node *parent, | |
229 | unsigned int pos) | |
230 | { | |
9606ca85 | 231 | _CMM_STORE_SHARED(node->parent, ((unsigned long) parent) | pos); |
7ba89e62 MD |
232 | } |
233 | ||
234 | static | |
235 | struct rcu_rbtree_node *get_parent(struct rcu_rbtree_node *node) | |
236 | { | |
237 | return (struct rcu_rbtree_node *) (node->parent & ~1UL); | |
238 | } | |
239 | ||
240 | static | |
241 | unsigned int get_pos(struct rcu_rbtree_node *node) | |
242 | { | |
243 | return (unsigned int) (node->parent & 1UL); | |
244 | } | |
245 | ||
246 | static | |
247 | struct rcu_rbtree_node *get_parent_and_pos(struct rcu_rbtree_node *node, | |
248 | unsigned int *pos) | |
249 | { | |
24b9b19b | 250 | unsigned long parent_pos = c_rcu_dereference(node->parent); |
7ba89e62 MD |
251 | |
252 | *pos = (unsigned int) (parent_pos & 1UL); | |
253 | return (struct rcu_rbtree_node *) (parent_pos & ~1UL); | |
254 | } | |
255 | ||
269a9ef6 MD |
256 | static |
257 | void set_decay(struct rcu_rbtree_node *x, struct rcu_rbtree_node *xc) | |
258 | { | |
259 | x->decay_next = xc; | |
260 | } | |
261 | ||
262 | static | |
263 | struct rcu_rbtree_node *get_decay(struct rcu_rbtree_node *x) | |
264 | { | |
dbe4ae98 MD |
265 | if (!x) |
266 | return NULL; | |
269a9ef6 MD |
267 | while (x->decay_next) |
268 | x = x->decay_next; | |
269 | return x; | |
270 | } | |
271 | ||
272 | static | |
273 | struct rcu_rbtree_node *is_decay(struct rcu_rbtree_node *x) | |
274 | { | |
275 | return x->decay_next; | |
276 | } | |
277 | ||
3c672595 | 278 | static |
8f354bc4 MD |
279 | struct rcu_rbtree_node *_rcu_rbtree_alloc_node(struct rcu_rbtree *rbtree) |
280 | { | |
281 | return rbtree->rballoc(sizeof(struct rcu_rbtree_node)); | |
282 | } | |
283 | ||
284 | static | |
285 | void _rcu_rbtree_free_node(struct rcu_head *head) | |
3c672595 MD |
286 | { |
287 | struct rcu_rbtree_node *node = | |
288 | caa_container_of(head, struct rcu_rbtree_node, head); | |
289 | node->rbtree->rbfree(node); | |
290 | } | |
291 | ||
c2ceb27c MD |
292 | #ifdef RBTREE_RCU_SUPPORT |
293 | ||
269a9ef6 MD |
294 | static |
295 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
296 | struct rcu_rbtree_node *x) | |
297 | { | |
298 | struct rcu_rbtree_node *xc; | |
299 | ||
8ded5fe9 | 300 | if (rcu_rbtree_is_nil(rbtree, x)) |
269a9ef6 MD |
301 | return x; |
302 | ||
8f354bc4 | 303 | xc = _rcu_rbtree_alloc_node(rbtree); |
3c672595 | 304 | memcpy(xc, x, sizeof(*xc)); |
269a9ef6 MD |
305 | xc->decay_next = NULL; |
306 | set_decay(x, xc); | |
1cdd423d | 307 | rbtree->call_rcu(&x->head, _rcu_rbtree_free_node); |
269a9ef6 MD |
308 | return xc; |
309 | } | |
310 | ||
c2ceb27c MD |
311 | #else /* RBTREE_RCU_SUPPORT */ |
312 | ||
313 | static | |
314 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
315 | struct rcu_rbtree_node *x) | |
316 | { | |
317 | return x; | |
318 | } | |
319 | ||
320 | #endif | |
321 | ||
dca45c9f MD |
322 | /* |
323 | * Info for range lookups: | |
324 | * Range lookup information is only valid when used when searching for | |
325 | * ranges. It should never be used in next/prev traversal because the | |
326 | * pointers to parents are not in sync with the parent vision of the | |
327 | * children range. | |
328 | */ | |
329 | static | |
a84e8c8e MD |
330 | void set_left(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
331 | struct rcu_rbtree_node *left) | |
dca45c9f | 332 | { |
dca45c9f | 333 | node->_left = left; |
dca45c9f MD |
334 | } |
335 | ||
336 | static | |
a84e8c8e MD |
337 | void set_right(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
338 | struct rcu_rbtree_node *right) | |
dca45c9f | 339 | { |
dca45c9f | 340 | node->_right = right; |
dca45c9f MD |
341 | } |
342 | ||
66b64c35 MD |
343 | static |
344 | void *calculate_node_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node) | |
345 | { | |
346 | void *max_end; | |
347 | ||
348 | max_end = node->end; | |
349 | if (!rcu_rbtree_is_nil(rbtree, node->_right)) { | |
350 | if (rbtree->comp(max_end, node->_right->max_end) < 0) | |
351 | max_end = node->_right->max_end; | |
352 | } | |
353 | if (!rcu_rbtree_is_nil(rbtree, node->_left)) { | |
354 | if (rbtree->comp(max_end, node->_left->max_end) < 0) | |
355 | max_end = node->_left->max_end; | |
356 | } | |
357 | return max_end; | |
358 | } | |
359 | ||
dff86257 MD |
360 | /* |
361 | * TODO | |
362 | * Deal with memory allocation errors. | |
363 | * Can be ensured by reserving a pool of memory entries before doing the | |
364 | * insertion, which will have to be function of number of | |
e20fb727 MD |
365 | * transplantations/rotations required for the operation (which is a |
366 | * multiple of the tree height). | |
dff86257 MD |
367 | */ |
368 | ||
5d2c985d | 369 | #ifdef DEBUG |
dff86257 MD |
370 | static |
371 | void show_tree(struct rcu_rbtree *rbtree) | |
372 | { | |
373 | struct rcu_rbtree_node *node; | |
374 | ||
375 | node = rcu_rbtree_min(rbtree, rbtree->root); | |
8ded5fe9 | 376 | while (!rcu_rbtree_is_nil(rbtree, node)) { |
269a9ef6 | 377 | assert(!is_decay(node)); |
fcb4eea8 | 378 | printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ", |
3366b9c0 MD |
379 | (unsigned long) node->begin, |
380 | (unsigned long) node->end, | |
381 | (unsigned long) get_parent(node)->begin, | |
fcb4eea8 MD |
382 | (unsigned long) node->_right->begin, |
383 | (unsigned long) node->_left->begin, | |
dff86257 | 384 | node->color ? "red" : "black", |
7ba89e62 | 385 | get_pos(node) ? "right" : "left", |
a84e8c8e | 386 | rcu_rbtree_is_nil(rbtree, node) ? "nil" : ""); |
dff86257 MD |
387 | node = rcu_rbtree_next(rbtree, node); |
388 | } | |
389 | printf("\n"); | |
390 | } | |
66b64c35 MD |
391 | |
392 | #define check_max_end(rbtree, x) \ | |
393 | do { \ | |
394 | if (rcu_rbtree_is_nil(rbtree, x)) \ | |
395 | break; \ | |
396 | assert(rbtree->comp(x->max_end, \ | |
397 | calculate_node_max_end(rbtree, x)) == 0); \ | |
398 | } while (0) | |
399 | ||
5d2c985d MD |
400 | #else /* DEBUG */ |
401 | static | |
402 | void show_tree(struct rcu_rbtree *rbtree) | |
403 | { | |
404 | } | |
66b64c35 MD |
405 | |
406 | static | |
407 | void check_max_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *x) | |
408 | { | |
409 | } | |
5d2c985d | 410 | #endif /* DEBUG */ |
dff86257 MD |
411 | |
412 | static | |
413 | struct rcu_rbtree_node *make_nil(struct rcu_rbtree *rbtree) | |
414 | { | |
415 | return &rbtree->nil_node; | |
416 | } | |
417 | ||
418 | /* | |
419 | * Iterative rbtree search. | |
420 | */ | |
00539351 | 421 | struct rcu_rbtree_node *rcu_rbtree_search(struct rcu_rbtree *rbtree, |
66b64c35 MD |
422 | struct rcu_rbtree_node *x, |
423 | void *point) | |
424 | { | |
425 | struct rcu_rbtree_node *xl; | |
426 | ||
427 | dbg_printf("searching point 0x%lx\n", (unsigned long) point); | |
24b9b19b | 428 | x = c_rcu_dereference(x); |
66b64c35 MD |
429 | |
430 | while (!rcu_rbtree_is_nil(rbtree, x)) { | |
431 | dbg_usleep(10); | |
24b9b19b | 432 | xl = c_rcu_dereference(x->_left); |
66b64c35 MD |
433 | dbg_printf("search x %lx x_end %lx x_max_end %lx\n", (unsigned long) x->begin, |
434 | (unsigned long) x->end, (unsigned long) x->max_end); | |
435 | dbg_printf("search xl %lx xl_end %lx xl_max_end %lx\n", (unsigned long) xl->begin, | |
436 | (unsigned long) xl->end, (unsigned long) xl->max_end); | |
437 | if (!rcu_rbtree_is_nil(rbtree, xl) | |
438 | && (rbtree->comp(xl->max_end, point) > 0)) { | |
439 | dbg_printf("go left\n"); | |
440 | x = xl; | |
3d8a234b | 441 | } else if (rbtree->comp(x->begin, point) <= 0 |
66b64c35 MD |
442 | && rbtree->comp(point, x->end) < 0) { |
443 | dbg_printf("got it!\n"); | |
444 | break; | |
445 | } else if (rbtree->comp(point, x->begin) > 0) { | |
446 | dbg_printf("go right\n"); | |
24b9b19b | 447 | x = c_rcu_dereference(x->_right); |
66b64c35 MD |
448 | } else { |
449 | dbg_printf("not found!\n"); | |
450 | x = make_nil(rbtree); | |
451 | } | |
452 | } | |
453 | if (rcu_rbtree_is_nil(rbtree, x)) | |
454 | dbg_printf("Reached bottom of tree.\n"); | |
455 | ||
456 | return x; | |
457 | } | |
458 | ||
459 | struct rcu_rbtree_node *rcu_rbtree_search_range(struct rcu_rbtree *rbtree, | |
460 | struct rcu_rbtree_node *x, | |
461 | void *begin, void *end) | |
462 | { | |
463 | struct rcu_rbtree_node *node; | |
464 | ||
465 | node = rcu_rbtree_search(rbtree, x, begin); | |
466 | if (rcu_rbtree_is_nil(rbtree, node)) | |
467 | return node; | |
468 | if (rbtree->comp(node->end, end) < 0) | |
469 | return NULL; /* High is outside lookup range */ | |
470 | return node; | |
471 | } | |
472 | ||
473 | /* | |
474 | * Search by exact range start value. | |
475 | */ | |
476 | struct rcu_rbtree_node *rcu_rbtree_search_begin_key(struct rcu_rbtree *rbtree, | |
dff86257 MD |
477 | struct rcu_rbtree_node *x, |
478 | void *k) | |
479 | { | |
24b9b19b | 480 | x = c_rcu_dereference(x); |
ac5f3963 | 481 | int comp; |
dff86257 | 482 | |
3366b9c0 | 483 | while (!rcu_rbtree_is_nil(rbtree, x) && (comp = rbtree->comp(k, x->begin)) != 0) { |
9c161ee1 | 484 | dbg_usleep(10); |
ac5f3963 | 485 | if (comp < 0) |
24b9b19b | 486 | x = c_rcu_dereference(x->_left); |
dff86257 | 487 | else |
24b9b19b | 488 | x = c_rcu_dereference(x->_right); |
dff86257 MD |
489 | } |
490 | return x; | |
491 | } | |
492 | ||
230dd288 MD |
493 | static |
494 | struct rcu_rbtree_node *rcu_rbtree_min_dup_decay(struct rcu_rbtree *rbtree, | |
495 | struct rcu_rbtree_node *x, | |
496 | struct rcu_rbtree_node **zr) | |
497 | { | |
498 | struct rcu_rbtree_node *xl; | |
499 | ||
24b9b19b | 500 | x = c_rcu_dereference(x); |
230dd288 | 501 | |
8ded5fe9 | 502 | if (rcu_rbtree_is_nil(rbtree, x)) { |
230dd288 MD |
503 | *zr = x; |
504 | return x; | |
505 | } else | |
506 | *zr = x = dup_decay_node(rbtree, x); | |
507 | ||
24b9b19b | 508 | while (!rcu_rbtree_is_nil(rbtree, xl = c_rcu_dereference(x->_left))) { |
230dd288 | 509 | x = dup_decay_node(rbtree, xl); |
7ba89e62 | 510 | set_parent(x, get_decay(get_parent(x)), get_pos(x)); |
dca45c9f | 511 | get_parent(x)->_left = get_decay(get_parent(x)->_left); |
230dd288 MD |
512 | } |
513 | return x; | |
514 | } | |
515 | ||
516 | static | |
517 | struct rcu_rbtree_node *rcu_rbtree_min_update_decay(struct rcu_rbtree *rbtree, | |
518 | struct rcu_rbtree_node *x) | |
519 | { | |
520 | struct rcu_rbtree_node *xl; | |
521 | ||
24b9b19b | 522 | x = c_rcu_dereference(x); |
230dd288 | 523 | |
8ded5fe9 | 524 | if (rcu_rbtree_is_nil(rbtree, x)) |
230dd288 MD |
525 | return x; |
526 | else { | |
dca45c9f MD |
527 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
528 | get_pos(x->_right)); | |
529 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
530 | get_pos(x->_left)); | |
230dd288 MD |
531 | } |
532 | ||
24b9b19b | 533 | while (!rcu_rbtree_is_nil(rbtree, xl = c_rcu_dereference(x->_left))) { |
230dd288 | 534 | x = xl; |
dca45c9f MD |
535 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
536 | get_pos(x->_right)); | |
537 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
538 | get_pos(x->_left)); | |
230dd288 MD |
539 | } |
540 | return x; | |
541 | } | |
542 | ||
dff86257 MD |
543 | struct rcu_rbtree_node *rcu_rbtree_min(struct rcu_rbtree *rbtree, |
544 | struct rcu_rbtree_node *x) | |
545 | { | |
546 | struct rcu_rbtree_node *xl; | |
547 | ||
24b9b19b | 548 | x = c_rcu_dereference(x); |
dff86257 | 549 | |
8ded5fe9 | 550 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
551 | return x; |
552 | ||
24b9b19b | 553 | while (!rcu_rbtree_is_nil(rbtree, xl = c_rcu_dereference(x->_left))) |
dff86257 MD |
554 | x = xl; |
555 | return x; | |
556 | } | |
557 | ||
558 | struct rcu_rbtree_node *rcu_rbtree_max(struct rcu_rbtree *rbtree, | |
559 | struct rcu_rbtree_node *x) | |
560 | { | |
561 | struct rcu_rbtree_node *xr; | |
562 | ||
24b9b19b | 563 | x = c_rcu_dereference(x); |
dff86257 | 564 | |
8ded5fe9 | 565 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
566 | return x; |
567 | ||
24b9b19b | 568 | while (!rcu_rbtree_is_nil(rbtree, xr = c_rcu_dereference(x->_right))) |
dff86257 MD |
569 | x = xr; |
570 | return x; | |
571 | } | |
572 | ||
dff86257 | 573 | /* |
7ba89e62 MD |
574 | * RCU read lock must be held across the next/prev calls to ensure validity of |
575 | * the returned node. | |
dff86257 MD |
576 | */ |
577 | struct rcu_rbtree_node *rcu_rbtree_next(struct rcu_rbtree *rbtree, | |
578 | struct rcu_rbtree_node *x) | |
579 | { | |
269a9ef6 | 580 | struct rcu_rbtree_node *xr, *y; |
7ba89e62 | 581 | unsigned int x_pos; |
dff86257 | 582 | |
24b9b19b | 583 | x = c_rcu_dereference(x); |
dff86257 | 584 | |
24b9b19b | 585 | if (!rcu_rbtree_is_nil(rbtree, xr = c_rcu_dereference(x->_right))) |
dff86257 | 586 | return rcu_rbtree_min(rbtree, xr); |
7ba89e62 | 587 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 588 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_RIGHT) { |
dff86257 | 589 | x = y; |
7ba89e62 | 590 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
591 | } |
592 | return y; | |
593 | } | |
594 | ||
595 | struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree *rbtree, | |
596 | struct rcu_rbtree_node *x) | |
597 | { | |
269a9ef6 | 598 | struct rcu_rbtree_node *xl, *y; |
7ba89e62 | 599 | unsigned int x_pos; |
dff86257 | 600 | |
24b9b19b | 601 | x = c_rcu_dereference(x); |
dff86257 | 602 | |
24b9b19b | 603 | if (!rcu_rbtree_is_nil(rbtree, xl = c_rcu_dereference(x->_left))) |
4aa30442 | 604 | return rcu_rbtree_max(rbtree, xl); |
7ba89e62 | 605 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 606 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_LEFT) { |
dff86257 | 607 | x = y; |
7ba89e62 | 608 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
609 | } |
610 | return y; | |
611 | } | |
612 | ||
7bc64d1d MD |
613 | /* |
614 | * "node" needs to be non-visible by readers. | |
615 | */ | |
616 | static | |
617 | void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, | |
fcb4eea8 | 618 | unsigned int copy_parents, struct rcu_rbtree_node *stop) |
7bc64d1d MD |
619 | { |
620 | struct rcu_rbtree_node *prev = NULL, *orig_node = node, *top; | |
621 | ||
622 | do { | |
623 | void *max_end; | |
624 | ||
fcb4eea8 | 625 | assert(node); |
7bc64d1d | 626 | assert(!rcu_rbtree_is_nil(rbtree, node)); |
4459c487 | 627 | |
66b64c35 MD |
628 | if (prev && copy_parents) { |
629 | node = dup_decay_node(rbtree, node); | |
630 | if (get_pos(prev) == IS_RIGHT) | |
631 | node->_right = prev; | |
632 | else | |
633 | node->_left = prev; | |
634 | set_parent(prev, node, get_pos(prev)); | |
635 | } | |
636 | ||
fda7316a | 637 | max_end = calculate_node_max_end(rbtree, node); |
66b64c35 MD |
638 | /* |
639 | * Compare the node max_end keys to make sure we replace | |
640 | * references to a key belonging to a node we remove | |
641 | * from the tree. Otherwise we would still be using this | |
642 | * pointer as an invalid reference after garbage | |
643 | * collection of the node and of its associated | |
644 | * begin/end pointers. | |
645 | */ | |
646 | if (max_end != node->max_end) { | |
7bc64d1d MD |
647 | node->max_end = max_end; |
648 | } else { | |
7bc64d1d MD |
649 | top = get_parent(node); |
650 | cmm_smp_wmb(); /* write into node before publish */ | |
651 | /* make new branch visible to readers */ | |
652 | if (rcu_rbtree_is_nil(rbtree, top)) | |
653 | _CMM_STORE_SHARED(rbtree->root, node); | |
654 | if (get_pos(node) == IS_LEFT) | |
655 | _CMM_STORE_SHARED(top->_left, node); | |
656 | else | |
657 | _CMM_STORE_SHARED(top->_right, node); | |
658 | goto end; | |
659 | } | |
fcb4eea8 MD |
660 | |
661 | /* Check for propagation stop */ | |
662 | if (node == stop) | |
663 | return; | |
664 | ||
7bc64d1d | 665 | prev = node; |
fcb4eea8 MD |
666 | node = get_parent(node); |
667 | } while (!rcu_rbtree_is_nil(rbtree, node)); | |
7bc64d1d MD |
668 | |
669 | top = node; /* nil */ | |
670 | cmm_smp_wmb(); /* write into node before publish */ | |
671 | /* make new branch visible to readers */ | |
672 | _CMM_STORE_SHARED(rbtree->root, prev); | |
673 | ||
674 | end: | |
fcb4eea8 MD |
675 | if (!copy_parents) |
676 | return; | |
7bc64d1d MD |
677 | /* update children */ |
678 | node = orig_node; | |
679 | do { | |
680 | assert(!rcu_rbtree_is_nil(rbtree, node)); | |
681 | set_parent(node->_left, get_decay(get_parent(node->_left)), IS_LEFT); | |
682 | set_parent(node->_right, get_decay(get_parent(node->_right)), IS_RIGHT); | |
683 | } while ((node = get_parent(node)) != top); | |
684 | } | |
685 | ||
dff86257 MD |
686 | /* |
687 | * We have to ensure these assumptions are correct for prev/next | |
688 | * traversal: | |
689 | * | |
690 | * with x being a right child, the assumption that: | |
dca45c9f | 691 | * get_parent(x)->_right == x |
dff86257 | 692 | * or if x is a left child, the assumption that: |
dca45c9f | 693 | * get_parent(x)->_left == x |
dff86257 MD |
694 | * |
695 | * This explains why we have to allocate a vc copy of the node for left_rotate, | |
696 | * right_rotate and transplant operations. | |
697 | * | |
698 | * We always ensure that the right/left child and correct parent is set in the | |
699 | * node copies *before* we reparent the children and make the upper-level point | |
700 | * to the copy. | |
701 | */ | |
702 | ||
703 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
704 | /* Should be eventually followed by a cmm_smp_wmc() */ | |
dff86257 | 705 | |
dbe4ae98 MD |
706 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_LEFT |
707 | ||
dff86257 | 708 | static |
269a9ef6 MD |
709 | void left_rotate(struct rcu_rbtree *rbtree, |
710 | struct rcu_rbtree_node *x) | |
dff86257 | 711 | { |
a84e8c8e | 712 | struct rcu_rbtree_node *y, *y_left; |
dff86257 | 713 | |
66b64c35 MD |
714 | dbg_printf("left rotate %lx\n", (unsigned long) x->begin); |
715 | ||
dca45c9f MD |
716 | y = x->_right; |
717 | y_left = y->_left; | |
269a9ef6 MD |
718 | |
719 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
720 | x = dup_decay_node(rbtree, x); |
721 | y = dup_decay_node(rbtree, y); | |
722 | y_left = dup_decay_node(rbtree, y_left); | |
269a9ef6 | 723 | |
66b64c35 MD |
724 | check_max_end(rbtree, get_parent(x)); |
725 | check_max_end(rbtree, x); | |
726 | check_max_end(rbtree, y); | |
727 | ||
676dd8b6 | 728 | /* Internal node modifications */ |
7ba89e62 MD |
729 | set_parent(y, get_parent(x), get_pos(x)); |
730 | set_parent(x, y, IS_LEFT); | |
a84e8c8e MD |
731 | set_left(rbtree, y, x); |
732 | set_right(rbtree, x, y_left); | |
dca45c9f | 733 | |
8ded5fe9 | 734 | if (!rcu_rbtree_is_nil(rbtree, y_left)) |
7ba89e62 | 735 | set_parent(y_left, x, IS_RIGHT); |
676dd8b6 | 736 | |
fda7316a MD |
737 | /* |
738 | * We only changed the relative position of x and y wrt their | |
739 | * children, and reparented y (but are keeping the same nodes in | |
740 | * place, so its parent does not need to have end value | |
741 | * recalculated). | |
742 | */ | |
743 | x->max_end = calculate_node_max_end(rbtree, x); | |
744 | y->max_end = calculate_node_max_end(rbtree, y); | |
745 | ||
676dd8b6 MD |
746 | cmm_smp_wmb(); /* write into node before publish */ |
747 | ||
748 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
749 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
750 | _CMM_STORE_SHARED(rbtree->root, y); | |
751 | else if (get_pos(y) == IS_LEFT) | |
752 | _CMM_STORE_SHARED(get_parent(y)->_left, y); | |
676dd8b6 | 753 | else |
a84e8c8e | 754 | _CMM_STORE_SHARED(get_parent(y)->_right, y); |
676dd8b6 | 755 | |
dbe4ae98 | 756 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
757 | set_parent(x->_left, get_decay(get_parent(x->_left)), |
758 | get_pos(x->_left)); | |
759 | set_parent(y->_right, get_decay(get_parent(y->_right)), | |
760 | get_pos(y->_right)); | |
8ded5fe9 | 761 | if (!rcu_rbtree_is_nil(rbtree, y_left)) { |
dca45c9f MD |
762 | set_parent(y_left->_right, |
763 | get_decay(get_parent(y_left->_right)), | |
764 | get_pos(y_left->_right)); | |
765 | set_parent(y_left->_left, | |
766 | get_decay(get_parent(y_left->_left)), | |
767 | get_pos(y_left->_left)); | |
dbe4ae98 | 768 | } |
269a9ef6 MD |
769 | |
770 | /* Sanity checks */ | |
dca45c9f MD |
771 | assert(y == rbtree->root || get_parent(y)->_left == y |
772 | || get_parent(y)->_right == y); | |
773 | assert(x == rbtree->root || get_parent(x)->_left == x | |
774 | || get_parent(x)->_right == x); | |
8ded5fe9 MD |
775 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); |
776 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); | |
777 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
778 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
269a9ef6 MD |
779 | assert(!is_decay(rbtree->root)); |
780 | assert(!is_decay(x)); | |
781 | assert(!is_decay(y)); | |
dca45c9f MD |
782 | assert(!is_decay(x->_right)); |
783 | assert(!is_decay(x->_left)); | |
784 | assert(!is_decay(y->_right)); | |
785 | assert(!is_decay(y->_left)); | |
66b64c35 MD |
786 | check_max_end(rbtree, get_parent(y)); |
787 | check_max_end(rbtree, x); | |
788 | check_max_end(rbtree, y); | |
dff86257 MD |
789 | } |
790 | ||
dbe4ae98 MD |
791 | #else |
792 | ||
793 | /* non-rcu version */ | |
794 | static | |
795 | void left_rotate(struct rcu_rbtree *rbtree, | |
796 | struct rcu_rbtree_node *x) | |
797 | { | |
798 | struct rcu_rbtree_node *y; | |
799 | ||
230dd288 | 800 | lock_test_mutex(); |
dca45c9f MD |
801 | y = x->_right; |
802 | x->_right = y->_left; | |
8ded5fe9 | 803 | if (!rcu_rbtree_is_nil(rbtree, y->_left)) |
dca45c9f | 804 | set_parent(y->_left, x, IS_RIGHT); |
7ba89e62 | 805 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 806 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
dbe4ae98 | 807 | rbtree->root = y; |
dca45c9f MD |
808 | else if (x == get_parent(x)->_left) { |
809 | get_parent(x)->_left = y; | |
dbe4ae98 | 810 | } else { |
dca45c9f | 811 | get_parent(x)->_right = y; |
dbe4ae98 | 812 | } |
dca45c9f | 813 | y->_left = x; |
7ba89e62 | 814 | set_parent(x, y, IS_LEFT); |
1444707c MD |
815 | |
816 | /* | |
817 | * We only changed the relative position of x and y wrt their | |
818 | * children, and reparented y (but are keeping the same nodes in | |
819 | * place, so its parent does not need to have end value | |
820 | * recalculated). | |
821 | */ | |
822 | x->max_end = calculate_node_max_end(rbtree, x); | |
823 | y->max_end = calculate_node_max_end(rbtree, y); | |
824 | ||
230dd288 | 825 | unlock_test_mutex(); |
dbe4ae98 MD |
826 | } |
827 | ||
828 | #endif | |
829 | ||
830 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
dff86257 | 831 | static |
269a9ef6 MD |
832 | void right_rotate(struct rcu_rbtree *rbtree, |
833 | struct rcu_rbtree_node *x) | |
dff86257 | 834 | { |
a84e8c8e | 835 | struct rcu_rbtree_node *y, *y_right; |
dff86257 | 836 | |
66b64c35 MD |
837 | dbg_printf("right rotate %lx\n", (unsigned long) x->begin); |
838 | ||
dca45c9f MD |
839 | y = x->_left; |
840 | y_right = y->_right; | |
269a9ef6 MD |
841 | |
842 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
843 | x = dup_decay_node(rbtree, x); |
844 | y = dup_decay_node(rbtree, y); | |
845 | y_right = dup_decay_node(rbtree, y_right); | |
269a9ef6 | 846 | |
66b64c35 MD |
847 | check_max_end(rbtree, get_parent(x)); |
848 | check_max_end(rbtree, x); | |
849 | check_max_end(rbtree, y); | |
850 | ||
676dd8b6 | 851 | /* Internal node modifications */ |
7ba89e62 MD |
852 | set_parent(y, get_parent(x), get_pos(x)); |
853 | set_parent(x, y, IS_RIGHT); | |
a84e8c8e MD |
854 | set_right(rbtree, y, x); |
855 | set_left(rbtree, x, y_right); | |
dca45c9f | 856 | |
8ded5fe9 | 857 | if (!rcu_rbtree_is_nil(rbtree, y_right)) |
7ba89e62 | 858 | set_parent(y_right, x, IS_LEFT); |
676dd8b6 | 859 | |
fda7316a MD |
860 | /* |
861 | * We only changed the relative position of x and y wrt their | |
862 | * children, and reparented y (but are keeping the same nodes in | |
863 | * place, so its parent does not need to have end value | |
864 | * recalculated). | |
865 | */ | |
866 | x->max_end = calculate_node_max_end(rbtree, x); | |
867 | y->max_end = calculate_node_max_end(rbtree, y); | |
868 | ||
676dd8b6 MD |
869 | cmm_smp_wmb(); /* write into node before publish */ |
870 | ||
871 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
872 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
873 | _CMM_STORE_SHARED(rbtree->root, y); | |
874 | else if (get_pos(y) == IS_RIGHT) | |
875 | _CMM_STORE_SHARED(get_parent(y)->_right, y); | |
676dd8b6 | 876 | else |
a84e8c8e | 877 | _CMM_STORE_SHARED(get_parent(y)->_left, y); |
676dd8b6 | 878 | |
dbe4ae98 | 879 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
880 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
881 | get_pos(x->_right)); | |
882 | set_parent(y->_left, get_decay(get_parent(y->_left)), | |
883 | get_pos(y->_left)); | |
8ded5fe9 | 884 | if (!rcu_rbtree_is_nil(rbtree, y_right)) { |
dca45c9f MD |
885 | set_parent(y_right->_left, |
886 | get_decay(get_parent(y_right->_left)), | |
887 | get_pos(y_right->_left)); | |
888 | set_parent(y_right->_right, | |
889 | get_decay(get_parent(y_right->_right)), | |
890 | get_pos(y_right->_right)); | |
dbe4ae98 | 891 | } |
269a9ef6 MD |
892 | |
893 | /* Sanity checks */ | |
dca45c9f MD |
894 | assert(y == rbtree->root || get_parent(y)->_right == y |
895 | || get_parent(y)->_left == y); | |
896 | assert(x == rbtree->root || get_parent(x)->_right == x | |
897 | || get_parent(x)->_left == x); | |
8ded5fe9 MD |
898 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); |
899 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); | |
900 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
901 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
269a9ef6 MD |
902 | assert(!is_decay(rbtree->root)); |
903 | assert(!is_decay(x)); | |
904 | assert(!is_decay(y)); | |
dca45c9f MD |
905 | assert(!is_decay(x->_left)); |
906 | assert(!is_decay(x->_right)); | |
907 | assert(!is_decay(y->_left)); | |
908 | assert(!is_decay(y->_right)); | |
66b64c35 MD |
909 | check_max_end(rbtree, x); |
910 | check_max_end(rbtree, y); | |
911 | check_max_end(rbtree, get_parent(y)); | |
dff86257 MD |
912 | } |
913 | ||
6daf6090 MD |
914 | #else |
915 | ||
dbe4ae98 | 916 | /* non-rcu version */ |
6daf6090 MD |
917 | static |
918 | void right_rotate(struct rcu_rbtree *rbtree, | |
919 | struct rcu_rbtree_node *x) | |
920 | { | |
921 | struct rcu_rbtree_node *y; | |
922 | ||
230dd288 | 923 | lock_test_mutex(); |
dca45c9f MD |
924 | y = x->_left; |
925 | x->_left = y->_right; | |
8ded5fe9 | 926 | if (!rcu_rbtree_is_nil(rbtree, y->_right)) |
dca45c9f | 927 | set_parent(y->_right, x, IS_LEFT); |
7ba89e62 | 928 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 929 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
6daf6090 | 930 | rbtree->root = y; |
dca45c9f MD |
931 | else if (x == get_parent(x)->_right) { |
932 | get_parent(x)->_right = y; | |
6daf6090 | 933 | } else { |
dca45c9f | 934 | get_parent(x)->_left = y; |
6daf6090 | 935 | } |
dca45c9f | 936 | y->_right = x; |
7ba89e62 | 937 | set_parent(x, y, IS_RIGHT); |
1444707c MD |
938 | |
939 | /* | |
940 | * We only changed the relative position of x and y wrt their | |
941 | * children, and reparented y (but are keeping the same nodes in | |
942 | * place, so its parent does not need to have end value | |
943 | * recalculated). | |
944 | */ | |
945 | x->max_end = calculate_node_max_end(rbtree, x); | |
946 | y->max_end = calculate_node_max_end(rbtree, y); | |
947 | ||
230dd288 | 948 | unlock_test_mutex(); |
6daf6090 MD |
949 | } |
950 | ||
951 | #endif | |
952 | ||
dff86257 MD |
953 | static void rcu_rbtree_insert_fixup(struct rcu_rbtree *rbtree, |
954 | struct rcu_rbtree_node *z) | |
955 | { | |
956 | struct rcu_rbtree_node *y; | |
957 | ||
3366b9c0 | 958 | dbg_printf("insert fixup %p\n", z->begin); |
269a9ef6 | 959 | assert(!is_decay(rbtree->root)); |
dff86257 | 960 | |
7ba89e62 | 961 | while (get_parent(z)->color == COLOR_RED) { |
dca45c9f MD |
962 | if (get_parent(z) == get_parent(get_parent(z))->_left) { |
963 | y = get_parent(get_parent(z))->_right; | |
dff86257 | 964 | if (y->color == COLOR_RED) { |
7ba89e62 | 965 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 966 | y->color = COLOR_BLACK; |
7ba89e62 MD |
967 | get_parent(get_parent(z))->color = COLOR_RED; |
968 | z = get_parent(get_parent(z)); | |
dff86257 | 969 | } else { |
dca45c9f | 970 | if (z == get_parent(z)->_right) { |
7ba89e62 | 971 | z = get_parent(z); |
dff86257 | 972 | left_rotate(rbtree, z); |
269a9ef6 MD |
973 | z = get_decay(z); |
974 | assert(!is_decay(rbtree->root)); | |
dff86257 | 975 | } |
7ba89e62 MD |
976 | get_parent(z)->color = COLOR_BLACK; |
977 | get_parent(get_parent(z))->color = COLOR_RED; | |
269a9ef6 | 978 | assert(!is_decay(z)); |
7ba89e62 MD |
979 | assert(!is_decay(get_parent(z))); |
980 | assert(!is_decay(get_parent(get_parent(z)))); | |
981 | right_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
982 | assert(!is_decay(z)); |
983 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
984 | } |
985 | } else { | |
dca45c9f | 986 | y = get_parent(get_parent(z))->_left; |
dff86257 | 987 | if (y->color == COLOR_RED) { |
7ba89e62 | 988 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 989 | y->color = COLOR_BLACK; |
7ba89e62 MD |
990 | get_parent(get_parent(z))->color = COLOR_RED; |
991 | z = get_parent(get_parent(z)); | |
dff86257 | 992 | } else { |
dca45c9f | 993 | if (z == get_parent(z)->_left) { |
7ba89e62 | 994 | z = get_parent(z); |
dff86257 | 995 | right_rotate(rbtree, z); |
269a9ef6 MD |
996 | z = get_decay(z); |
997 | assert(!is_decay(rbtree->root)); | |
dff86257 | 998 | } |
7ba89e62 MD |
999 | get_parent(z)->color = COLOR_BLACK; |
1000 | get_parent(get_parent(z))->color = COLOR_RED; | |
1001 | left_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
1002 | assert(!is_decay(z)); |
1003 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
1004 | } |
1005 | } | |
1006 | } | |
1007 | rbtree->root->color = COLOR_BLACK; | |
1008 | } | |
1009 | ||
1010 | /* | |
1011 | * rcu_rbtree_insert - Insert a node in the RCU rbtree | |
1012 | * | |
1013 | * Returns 0 on success, or < 0 on error. | |
1014 | */ | |
1015 | int rcu_rbtree_insert(struct rcu_rbtree *rbtree, | |
3c672595 | 1016 | void *begin, void *end) |
dff86257 | 1017 | { |
3c672595 MD |
1018 | struct rcu_rbtree_node *x, *y, *z; |
1019 | ||
8f354bc4 MD |
1020 | z = _rcu_rbtree_alloc_node(rbtree); |
1021 | if (!z) | |
1022 | return -ENOMEM; | |
3c672595 MD |
1023 | z->begin = begin; |
1024 | z->end = end; | |
dff86257 | 1025 | |
3366b9c0 | 1026 | dbg_printf("insert %p\n", z->begin); |
269a9ef6 | 1027 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1028 | |
1029 | y = make_nil(rbtree); | |
dff86257 | 1030 | x = rbtree->root; |
8ded5fe9 | 1031 | while (!rcu_rbtree_is_nil(rbtree, x)) { |
dff86257 | 1032 | y = x; |
3366b9c0 | 1033 | if (rbtree->comp(z->begin, x->begin) < 0) |
dca45c9f | 1034 | x = x->_left; |
dff86257 | 1035 | else |
dca45c9f | 1036 | x = x->_right; |
dff86257 MD |
1037 | } |
1038 | ||
dca45c9f MD |
1039 | z->_left = make_nil(rbtree); |
1040 | z->_right = make_nil(rbtree); | |
dff86257 | 1041 | z->color = COLOR_RED; |
269a9ef6 | 1042 | z->decay_next = NULL; |
55b5e812 | 1043 | z->max_end = z->end; |
3c672595 | 1044 | z->rbtree = rbtree; |
dff86257 | 1045 | |
8ded5fe9 | 1046 | if (rcu_rbtree_is_nil(rbtree, y)) { |
7bc64d1d | 1047 | set_parent(z, y, IS_RIGHT); /* pos arbitrary for root node */ |
0bd215cc MD |
1048 | /* |
1049 | * Order stores to z (children/parents) before stores | |
1050 | * that will make it visible to the rest of the tree. | |
1051 | */ | |
1052 | cmm_smp_wmb(); | |
dff86257 | 1053 | _CMM_STORE_SHARED(rbtree->root, z); |
3366b9c0 | 1054 | } else if (rbtree->comp(z->begin, y->begin) < 0) { |
7bc64d1d MD |
1055 | y = dup_decay_node(rbtree, y); |
1056 | set_parent(z, y, IS_LEFT); | |
1057 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 1058 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 1059 | else |
a84e8c8e | 1060 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 1061 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 1062 | } else { |
7bc64d1d MD |
1063 | y = dup_decay_node(rbtree, y); |
1064 | set_parent(z, y, IS_RIGHT); | |
1065 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 1066 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 1067 | else |
a84e8c8e | 1068 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 1069 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 1070 | } |
dff86257 MD |
1071 | rcu_rbtree_insert_fixup(rbtree, z); |
1072 | /* | |
1073 | * Make sure to commit all _CMM_STORE_SHARED() for non-coherent caches. | |
1074 | */ | |
1075 | cmm_smp_wmc(); | |
1076 | show_tree(rbtree); | |
66b64c35 MD |
1077 | check_max_end(rbtree, z); |
1078 | check_max_end(rbtree, y); | |
dff86257 MD |
1079 | |
1080 | return 0; | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * Transplant v into u position. | |
dff86257 | 1085 | */ |
6daf6090 MD |
1086 | |
1087 | #ifdef RBTREE_RCU_SUPPORT_TRANSPLANT | |
1088 | ||
269a9ef6 MD |
1089 | static |
1090 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1091 | struct rcu_rbtree_node *u, | |
dca45c9f | 1092 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1093 | unsigned int copy_parents, |
1094 | struct rcu_rbtree_node *stop) | |
dff86257 | 1095 | { |
3366b9c0 | 1096 | dbg_printf("transplant %p\n", v->begin); |
dff86257 | 1097 | |
8ded5fe9 | 1098 | if (!rcu_rbtree_is_nil(rbtree, v)) |
dbe4ae98 | 1099 | v = dup_decay_node(rbtree, v); |
c479601c | 1100 | |
8ded5fe9 | 1101 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
7ba89e62 MD |
1102 | /* pos is arbitrary for root node */ |
1103 | set_parent(v, get_parent(u), IS_RIGHT); | |
c479601c MD |
1104 | cmm_smp_wmb(); /* write into node before publish */ |
1105 | _CMM_STORE_SHARED(rbtree->root, v); | |
dff86257 | 1106 | } else { |
fcb4eea8 MD |
1107 | struct rcu_rbtree_node *vp; |
1108 | ||
1109 | vp = get_parent(u); | |
1110 | if (copy_parents) | |
1111 | vp = dup_decay_node(rbtree, vp); | |
1112 | set_parent(v, vp, get_pos(u)); | |
1113 | if (get_pos(v) == IS_LEFT) | |
1114 | _CMM_STORE_SHARED(vp->_left, v); | |
806967f3 | 1115 | else |
fcb4eea8 MD |
1116 | _CMM_STORE_SHARED(vp->_right, v); |
1117 | populate_node_end(rbtree, vp, copy_parents, stop); | |
66b64c35 | 1118 | check_max_end(rbtree, vp); |
c479601c | 1119 | } |
806967f3 | 1120 | |
dbe4ae98 | 1121 | /* Point children to new copy (parent only used by updates/next/prev) */ |
8ded5fe9 | 1122 | if (!rcu_rbtree_is_nil(rbtree, v)) { |
dca45c9f MD |
1123 | set_parent(v->_right, get_decay(get_parent(v->_right)), |
1124 | get_pos(v->_right)); | |
1125 | set_parent(v->_left, get_decay(get_parent(v->_left)), | |
1126 | get_pos(v->_left)); | |
dff86257 | 1127 | } |
269a9ef6 | 1128 | assert(!is_decay(rbtree->root)); |
66b64c35 | 1129 | check_max_end(rbtree, v); |
dff86257 MD |
1130 | } |
1131 | ||
6daf6090 MD |
1132 | #else |
1133 | ||
1134 | /* Non-RCU version */ | |
1135 | static | |
1136 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
1137 | struct rcu_rbtree_node *u, | |
dca45c9f | 1138 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
1139 | unsigned int copy_parents, |
1140 | struct rcu_rbtree_node *stop) | |
6daf6090 | 1141 | { |
3366b9c0 | 1142 | dbg_printf("transplant %p\n", v->begin); |
6daf6090 | 1143 | |
230dd288 | 1144 | lock_test_mutex(); |
1444707c | 1145 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
6daf6090 | 1146 | rbtree->root = v; |
1444707c MD |
1147 | } else { |
1148 | if (u == get_parent(u)->_left) | |
1149 | get_parent(u)->_left = v; | |
1150 | else | |
1151 | get_parent(u)->_right = v; | |
1152 | populate_node_end(rbtree, get_parent(u), copy_parents, stop); | |
1153 | } | |
7ba89e62 | 1154 | set_parent(v, get_parent(u), get_pos(u)); |
230dd288 | 1155 | unlock_test_mutex(); |
6daf6090 MD |
1156 | } |
1157 | ||
1158 | #endif | |
1159 | ||
dff86257 MD |
1160 | static void rcu_rbtree_remove_fixup(struct rcu_rbtree *rbtree, |
1161 | struct rcu_rbtree_node *x) | |
1162 | { | |
3366b9c0 | 1163 | dbg_printf("remove fixup %p\n", x->begin); |
dff86257 MD |
1164 | |
1165 | while (x != rbtree->root && x->color == COLOR_BLACK) { | |
7ba89e62 | 1166 | assert(!is_decay(get_parent(x))); |
dca45c9f MD |
1167 | assert(!is_decay(get_parent(x)->_left)); |
1168 | if (x == get_parent(x)->_left) { | |
269a9ef6 | 1169 | struct rcu_rbtree_node *w; |
dff86257 | 1170 | |
dca45c9f | 1171 | w = get_parent(x)->_right; |
dff86257 MD |
1172 | |
1173 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1174 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1175 | get_parent(x)->color = COLOR_RED; |
1176 | left_rotate(rbtree, get_parent(x)); | |
269a9ef6 MD |
1177 | x = get_decay(x); |
1178 | assert(!is_decay(rbtree->root)); | |
dca45c9f | 1179 | w = get_parent(x)->_right; |
dff86257 | 1180 | } |
dca45c9f MD |
1181 | if (w->_left->color == COLOR_BLACK |
1182 | && w->_right->color == COLOR_BLACK) { | |
dff86257 | 1183 | w->color = COLOR_RED; |
7ba89e62 | 1184 | x = get_parent(x); |
c479601c MD |
1185 | assert(!is_decay(rbtree->root)); |
1186 | assert(!is_decay(x)); | |
dff86257 | 1187 | } else { |
dca45c9f MD |
1188 | if (w->_right->color == COLOR_BLACK) { |
1189 | w->_left->color = COLOR_BLACK; | |
dff86257 MD |
1190 | w->color = COLOR_RED; |
1191 | right_rotate(rbtree, w); | |
c479601c | 1192 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1193 | x = get_decay(x); |
dca45c9f | 1194 | w = get_parent(x)->_right; |
dff86257 | 1195 | } |
7ba89e62 MD |
1196 | w->color = get_parent(x)->color; |
1197 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1198 | w->_right->color = COLOR_BLACK; |
7ba89e62 | 1199 | left_rotate(rbtree, get_parent(x)); |
269a9ef6 | 1200 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1201 | x = rbtree->root; |
1202 | } | |
1203 | } else { | |
269a9ef6 | 1204 | struct rcu_rbtree_node *w; |
dff86257 | 1205 | |
dca45c9f | 1206 | w = get_parent(x)->_left; |
dff86257 MD |
1207 | |
1208 | if (w->color == COLOR_RED) { | |
269a9ef6 | 1209 | w->color = COLOR_BLACK; |
7ba89e62 MD |
1210 | get_parent(x)->color = COLOR_RED; |
1211 | right_rotate(rbtree, get_parent(x)); | |
c479601c | 1212 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 1213 | x = get_decay(x); |
dca45c9f | 1214 | w = get_parent(x)->_left; |
dff86257 | 1215 | } |
dca45c9f MD |
1216 | if (w->_right->color == COLOR_BLACK |
1217 | && w->_left->color == COLOR_BLACK) { | |
dff86257 | 1218 | w->color = COLOR_RED; |
7ba89e62 | 1219 | x = get_parent(x); |
c479601c MD |
1220 | assert(!is_decay(rbtree->root)); |
1221 | assert(!is_decay(x)); | |
dff86257 | 1222 | } else { |
dca45c9f MD |
1223 | if (w->_left->color == COLOR_BLACK) { |
1224 | w->_right->color = COLOR_BLACK; | |
dff86257 MD |
1225 | w->color = COLOR_RED; |
1226 | left_rotate(rbtree, w); | |
269a9ef6 MD |
1227 | assert(!is_decay(rbtree->root)); |
1228 | x = get_decay(x); | |
dca45c9f | 1229 | w = get_parent(x)->_left; |
dff86257 | 1230 | } |
7ba89e62 MD |
1231 | w->color = get_parent(x)->color; |
1232 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 1233 | w->_left->color = COLOR_BLACK; |
7ba89e62 | 1234 | right_rotate(rbtree, get_parent(x)); |
c479601c | 1235 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
1236 | x = rbtree->root; |
1237 | } | |
1238 | } | |
1239 | } | |
1240 | x->color = COLOR_BLACK; | |
1241 | } | |
1242 | ||
1243 | /* | |
269a9ef6 MD |
1244 | * Delete z. All non-copied children left/right positions are unchanged. |
1245 | */ | |
1246 | static | |
1247 | void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, | |
1248 | struct rcu_rbtree_node *z, | |
1249 | struct rcu_rbtree_node *y) | |
dff86257 | 1250 | { |
a84e8c8e | 1251 | struct rcu_rbtree_node *x; |
dff86257 | 1252 | |
3366b9c0 | 1253 | dbg_printf("remove nonil %p\n", z->begin); |
dff86257 MD |
1254 | show_tree(rbtree); |
1255 | ||
c479601c MD |
1256 | assert(!is_decay(z)); |
1257 | assert(!is_decay(y)); | |
dca45c9f | 1258 | assert(!is_decay(y->_right)); |
7ba89e62 | 1259 | assert(!is_decay(get_parent(y))); |
dca45c9f | 1260 | x = y->_right; |
c479601c | 1261 | assert(!is_decay(x)); |
7ba89e62 | 1262 | if (get_parent(y) == z) { |
230dd288 | 1263 | y = dup_decay_node(rbtree, y); |
7ba89e62 | 1264 | set_parent(x, y, get_pos(x)); /* parent for nil */ |
66b64c35 | 1265 | /* y is z's right node */ |
a84e8c8e | 1266 | set_left(rbtree, y, z->_left); |
66b64c35 | 1267 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1268 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 MD |
1269 | } else { |
1270 | struct rcu_rbtree_node *oy_right, *z_right; | |
1271 | ||
1272 | /* | |
1273 | * Need to make sure y is always visible by readers. | |
1274 | */ | |
dca45c9f | 1275 | y = rcu_rbtree_min_dup_decay(rbtree, z->_right, &z_right); |
269a9ef6 MD |
1276 | assert(!is_decay(y)); |
1277 | assert(!is_decay(z)); | |
dca45c9f MD |
1278 | oy_right = y->_right; |
1279 | ||
1280 | /* | |
3366b9c0 | 1281 | * The max child begin of z_right does not change, because |
dca45c9f MD |
1282 | * we're only changing its left children. |
1283 | */ | |
1284 | y->_right = z_right; | |
1285 | set_parent(y->_right, y, IS_RIGHT); | |
dca45c9f MD |
1286 | assert(!is_decay(z->_left)); |
1287 | y->_left = z->_left; | |
230dd288 | 1288 | assert(!is_decay(oy_right)); |
dca45c9f MD |
1289 | /* |
1290 | * Transplant of oy_right to old y's location will only | |
fcb4eea8 | 1291 | * trigger a "end" value update of the already copied branch |
dca45c9f MD |
1292 | * (which is not visible yet). We are transplanting |
1293 | * oy_right as a left child of old y's parent, so the | |
1294 | * min values update propagated upward necessarily stops | |
1295 | * at z_right. | |
1296 | */ | |
fcb4eea8 | 1297 | rcu_rbtree_transplant(rbtree, y, oy_right, 0, y); |
66b64c35 | 1298 | y->max_end = calculate_node_max_end(rbtree, y); |
fcb4eea8 | 1299 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 | 1300 | /* Update children */ |
dca45c9f | 1301 | (void) rcu_rbtree_min_update_decay(rbtree, y->_right); |
dff86257 | 1302 | } |
c479601c | 1303 | y = get_decay(y); |
269a9ef6 | 1304 | assert(!is_decay(z)); |
dca45c9f | 1305 | assert(!is_decay(z->_left)); |
dff86257 | 1306 | y->color = z->color; |
dca45c9f MD |
1307 | set_parent(y->_left, y, IS_LEFT); |
1308 | set_parent(y->_right, get_decay(get_parent(y->_right)), IS_RIGHT); | |
1309 | assert(!is_decay(y->_left)); | |
1310 | assert(!is_decay(y->_right)); | |
dff86257 MD |
1311 | } |
1312 | ||
1313 | int rcu_rbtree_remove(struct rcu_rbtree *rbtree, | |
1314 | struct rcu_rbtree_node *z) | |
1315 | { | |
1316 | struct rcu_rbtree_node *x, *y; | |
1317 | unsigned int y_original_color; | |
1318 | ||
269a9ef6 | 1319 | assert(!is_decay(rbtree->root)); |
3366b9c0 | 1320 | dbg_printf("remove %p\n", z->begin); |
dff86257 MD |
1321 | show_tree(rbtree); |
1322 | ||
c479601c | 1323 | assert(!is_decay(z)); |
dff86257 MD |
1324 | y = z; |
1325 | y_original_color = y->color; | |
1326 | ||
8ded5fe9 | 1327 | if (rcu_rbtree_is_nil(rbtree, z->_left)) { |
fcb4eea8 | 1328 | rcu_rbtree_transplant(rbtree, z, z->_right, 1, NULL); |
269a9ef6 | 1329 | assert(!is_decay(z)); |
dca45c9f | 1330 | x = get_decay(z->_right); |
dff86257 | 1331 | show_tree(rbtree); |
8ded5fe9 | 1332 | } else if (rcu_rbtree_is_nil(rbtree, z->_right)) { |
fcb4eea8 | 1333 | rcu_rbtree_transplant(rbtree, z, z->_left, 1, NULL); |
269a9ef6 | 1334 | assert(!is_decay(z)); |
dca45c9f | 1335 | x = get_decay(z->_left); |
dff86257 MD |
1336 | show_tree(rbtree); |
1337 | } else { | |
dca45c9f | 1338 | y = rcu_rbtree_min(rbtree, z->_right); |
c479601c | 1339 | assert(!is_decay(y)); |
dff86257 | 1340 | y_original_color = y->color; |
dca45c9f | 1341 | x = y->_right; |
269a9ef6 | 1342 | rcu_rbtree_remove_nonil(rbtree, z, y); |
6daf6090 | 1343 | x = get_decay(x); |
dff86257 MD |
1344 | show_tree(rbtree); |
1345 | } | |
1346 | if (y_original_color == COLOR_BLACK) | |
1347 | rcu_rbtree_remove_fixup(rbtree, x); | |
1348 | show_tree(rbtree); | |
66b64c35 MD |
1349 | check_max_end(rbtree, x); |
1350 | check_max_end(rbtree, get_decay(y)); | |
dff86257 MD |
1351 | /* |
1352 | * Commit all _CMM_STORE_SHARED(). | |
1353 | */ | |
1354 | cmm_smp_wmc(); | |
c2ceb27c | 1355 | #ifdef RBTREE_RCU_SUPPORT |
1cdd423d | 1356 | rbtree->call_rcu(&z->head, _rcu_rbtree_free_node); |
c2ceb27c MD |
1357 | #else |
1358 | _rcu_rbtree_free_node(&z->head); | |
1359 | #endif | |
dff86257 MD |
1360 | |
1361 | return 0; | |
1362 | } |