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