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 | |
dff86257 MD |
44 | #ifdef DEBUG |
45 | #define dbg_printf(args...) printf(args) | |
9c161ee1 | 46 | #define dbg_usleep(usecs) usleep(usecs) |
dff86257 MD |
47 | #else |
48 | #define dbg_printf(args...) | |
9c161ee1 | 49 | #define dbg_usleep(usecs) |
dff86257 MD |
50 | #endif |
51 | ||
6daf6090 MD |
52 | /* |
53 | * Undefine this to enable the non-RCU rotate and transplant functions | |
54 | * (for debugging). | |
55 | */ | |
dbe4ae98 MD |
56 | #define RBTREE_RCU_SUPPORT_ROTATE_LEFT |
57 | #define RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
6daf6090 MD |
58 | #define RBTREE_RCU_SUPPORT_TRANSPLANT |
59 | ||
230dd288 MD |
60 | #ifdef EXTRA_DEBUG |
61 | static pthread_mutex_t test_mutex = PTHREAD_MUTEX_INITIALIZER; | |
62 | static pthread_mutex_t outer_mutex = PTHREAD_MUTEX_INITIALIZER; | |
63 | ||
64 | static | |
65 | void lock_outer_mutex(void) | |
66 | { | |
67 | pthread_mutex_lock(&outer_mutex); | |
68 | } | |
69 | ||
70 | static | |
71 | void unlock_outer_mutex(void) | |
72 | { | |
73 | pthread_mutex_unlock(&outer_mutex); | |
74 | } | |
75 | ||
76 | static | |
77 | void lock_test_mutex(void) | |
78 | { | |
79 | pthread_mutex_lock(&test_mutex); | |
80 | } | |
81 | ||
82 | static | |
83 | void unlock_test_mutex(void) | |
84 | { | |
85 | pthread_mutex_unlock(&test_mutex); | |
86 | } | |
87 | #endif | |
88 | ||
7ba89e62 MD |
89 | static |
90 | void set_parent(struct rcu_rbtree_node *node, | |
91 | struct rcu_rbtree_node *parent, | |
92 | unsigned int pos) | |
93 | { | |
9606ca85 | 94 | _CMM_STORE_SHARED(node->parent, ((unsigned long) parent) | pos); |
7ba89e62 MD |
95 | } |
96 | ||
97 | static | |
98 | struct rcu_rbtree_node *get_parent(struct rcu_rbtree_node *node) | |
99 | { | |
100 | return (struct rcu_rbtree_node *) (node->parent & ~1UL); | |
101 | } | |
102 | ||
103 | static | |
104 | unsigned int get_pos(struct rcu_rbtree_node *node) | |
105 | { | |
106 | return (unsigned int) (node->parent & 1UL); | |
107 | } | |
108 | ||
109 | static | |
110 | struct rcu_rbtree_node *get_parent_and_pos(struct rcu_rbtree_node *node, | |
111 | unsigned int *pos) | |
112 | { | |
113 | unsigned long parent_pos = rcu_dereference(node->parent); | |
114 | ||
115 | *pos = (unsigned int) (parent_pos & 1UL); | |
116 | return (struct rcu_rbtree_node *) (parent_pos & ~1UL); | |
117 | } | |
118 | ||
269a9ef6 MD |
119 | static |
120 | void set_decay(struct rcu_rbtree_node *x, struct rcu_rbtree_node *xc) | |
121 | { | |
122 | x->decay_next = xc; | |
123 | } | |
124 | ||
125 | static | |
126 | struct rcu_rbtree_node *get_decay(struct rcu_rbtree_node *x) | |
127 | { | |
dbe4ae98 MD |
128 | if (!x) |
129 | return NULL; | |
269a9ef6 MD |
130 | while (x->decay_next) |
131 | x = x->decay_next; | |
132 | return x; | |
133 | } | |
134 | ||
135 | static | |
136 | struct rcu_rbtree_node *is_decay(struct rcu_rbtree_node *x) | |
137 | { | |
138 | return x->decay_next; | |
139 | } | |
140 | ||
141 | static | |
142 | struct rcu_rbtree_node *dup_decay_node(struct rcu_rbtree *rbtree, | |
143 | struct rcu_rbtree_node *x) | |
144 | { | |
145 | struct rcu_rbtree_node *xc; | |
146 | ||
8ded5fe9 | 147 | if (rcu_rbtree_is_nil(rbtree, x)) |
269a9ef6 MD |
148 | return x; |
149 | ||
150 | xc = rbtree->rballoc(); | |
151 | memcpy(xc, x, sizeof(struct rcu_rbtree_node)); | |
152 | xc->decay_next = NULL; | |
153 | set_decay(x, xc); | |
c479601c | 154 | call_rcu(&x->head, rbtree->rbfree); |
269a9ef6 MD |
155 | return xc; |
156 | } | |
157 | ||
dca45c9f MD |
158 | /* |
159 | * Info for range lookups: | |
160 | * Range lookup information is only valid when used when searching for | |
161 | * ranges. It should never be used in next/prev traversal because the | |
162 | * pointers to parents are not in sync with the parent vision of the | |
163 | * children range. | |
164 | */ | |
165 | static | |
a84e8c8e MD |
166 | void set_left(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
167 | struct rcu_rbtree_node *left) | |
dca45c9f | 168 | { |
dca45c9f | 169 | node->_left = left; |
dca45c9f MD |
170 | } |
171 | ||
172 | static | |
a84e8c8e MD |
173 | void set_right(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, |
174 | struct rcu_rbtree_node *right) | |
dca45c9f | 175 | { |
dca45c9f | 176 | node->_right = right; |
dca45c9f MD |
177 | } |
178 | ||
dff86257 MD |
179 | /* |
180 | * TODO | |
181 | * Deal with memory allocation errors. | |
182 | * Can be ensured by reserving a pool of memory entries before doing the | |
183 | * insertion, which will have to be function of number of | |
184 | * transplantations/rotations required for the operation. | |
185 | */ | |
186 | ||
5d2c985d | 187 | #ifdef DEBUG |
dff86257 MD |
188 | static |
189 | void show_tree(struct rcu_rbtree *rbtree) | |
190 | { | |
191 | struct rcu_rbtree_node *node; | |
192 | ||
193 | node = rcu_rbtree_min(rbtree, rbtree->root); | |
8ded5fe9 | 194 | while (!rcu_rbtree_is_nil(rbtree, node)) { |
269a9ef6 | 195 | assert(!is_decay(node)); |
fcb4eea8 | 196 | printf("{ b:%lX e:%lX pb: %lX r:%lX l:%lX %s %s %s} ", |
3366b9c0 MD |
197 | (unsigned long) node->begin, |
198 | (unsigned long) node->end, | |
199 | (unsigned long) get_parent(node)->begin, | |
fcb4eea8 MD |
200 | (unsigned long) node->_right->begin, |
201 | (unsigned long) node->_left->begin, | |
dff86257 | 202 | node->color ? "red" : "black", |
7ba89e62 | 203 | get_pos(node) ? "right" : "left", |
a84e8c8e | 204 | rcu_rbtree_is_nil(rbtree, node) ? "nil" : ""); |
dff86257 MD |
205 | node = rcu_rbtree_next(rbtree, node); |
206 | } | |
207 | printf("\n"); | |
208 | } | |
5d2c985d MD |
209 | #else /* DEBUG */ |
210 | static | |
211 | void show_tree(struct rcu_rbtree *rbtree) | |
212 | { | |
213 | } | |
214 | #endif /* DEBUG */ | |
dff86257 MD |
215 | |
216 | static | |
217 | struct rcu_rbtree_node *make_nil(struct rcu_rbtree *rbtree) | |
218 | { | |
219 | return &rbtree->nil_node; | |
220 | } | |
221 | ||
222 | /* | |
223 | * Iterative rbtree search. | |
224 | */ | |
00539351 | 225 | struct rcu_rbtree_node *rcu_rbtree_search(struct rcu_rbtree *rbtree, |
dff86257 MD |
226 | struct rcu_rbtree_node *x, |
227 | void *k) | |
228 | { | |
229 | x = rcu_dereference(x); | |
ac5f3963 | 230 | int comp; |
dff86257 | 231 | |
3366b9c0 | 232 | while (!rcu_rbtree_is_nil(rbtree, x) && (comp = rbtree->comp(k, x->begin)) != 0) { |
9c161ee1 | 233 | dbg_usleep(10); |
ac5f3963 | 234 | if (comp < 0) |
dca45c9f | 235 | x = rcu_dereference(x->_left); |
dff86257 | 236 | else |
dca45c9f | 237 | x = rcu_dereference(x->_right); |
dff86257 MD |
238 | } |
239 | return x; | |
240 | } | |
241 | ||
230dd288 MD |
242 | static |
243 | struct rcu_rbtree_node *rcu_rbtree_min_dup_decay(struct rcu_rbtree *rbtree, | |
244 | struct rcu_rbtree_node *x, | |
245 | struct rcu_rbtree_node **zr) | |
246 | { | |
247 | struct rcu_rbtree_node *xl; | |
248 | ||
249 | x = rcu_dereference(x); | |
250 | ||
8ded5fe9 | 251 | if (rcu_rbtree_is_nil(rbtree, x)) { |
230dd288 MD |
252 | *zr = x; |
253 | return x; | |
254 | } else | |
255 | *zr = x = dup_decay_node(rbtree, x); | |
256 | ||
8ded5fe9 | 257 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 258 | x = dup_decay_node(rbtree, xl); |
7ba89e62 | 259 | set_parent(x, get_decay(get_parent(x)), get_pos(x)); |
dca45c9f | 260 | get_parent(x)->_left = get_decay(get_parent(x)->_left); |
230dd288 MD |
261 | } |
262 | return x; | |
263 | } | |
264 | ||
265 | static | |
266 | struct rcu_rbtree_node *rcu_rbtree_min_update_decay(struct rcu_rbtree *rbtree, | |
267 | struct rcu_rbtree_node *x) | |
268 | { | |
269 | struct rcu_rbtree_node *xl; | |
270 | ||
271 | x = rcu_dereference(x); | |
272 | ||
8ded5fe9 | 273 | if (rcu_rbtree_is_nil(rbtree, x)) |
230dd288 MD |
274 | return x; |
275 | else { | |
dca45c9f MD |
276 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
277 | get_pos(x->_right)); | |
278 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
279 | get_pos(x->_left)); | |
230dd288 MD |
280 | } |
281 | ||
8ded5fe9 | 282 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) { |
230dd288 | 283 | x = xl; |
dca45c9f MD |
284 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
285 | get_pos(x->_right)); | |
286 | set_parent(x->_left, get_decay(get_parent(x->_left)), | |
287 | get_pos(x->_left)); | |
230dd288 MD |
288 | } |
289 | return x; | |
290 | } | |
291 | ||
dff86257 MD |
292 | struct rcu_rbtree_node *rcu_rbtree_min(struct rcu_rbtree *rbtree, |
293 | struct rcu_rbtree_node *x) | |
294 | { | |
295 | struct rcu_rbtree_node *xl; | |
296 | ||
297 | x = rcu_dereference(x); | |
298 | ||
8ded5fe9 | 299 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
300 | return x; |
301 | ||
8ded5fe9 | 302 | while (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
dff86257 MD |
303 | x = xl; |
304 | return x; | |
305 | } | |
306 | ||
307 | struct rcu_rbtree_node *rcu_rbtree_max(struct rcu_rbtree *rbtree, | |
308 | struct rcu_rbtree_node *x) | |
309 | { | |
310 | struct rcu_rbtree_node *xr; | |
311 | ||
312 | x = rcu_dereference(x); | |
313 | ||
8ded5fe9 | 314 | if (rcu_rbtree_is_nil(rbtree, x)) |
dff86257 MD |
315 | return x; |
316 | ||
8ded5fe9 | 317 | while (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 MD |
318 | x = xr; |
319 | return x; | |
320 | } | |
321 | ||
322 | /* | |
323 | * FIXME: | |
324 | * Updates should wait for a grace period between update of the | |
325 | * redirect pointer and update of the parent child pointer. This is to make sure | |
326 | * that no reference to the old entry exist. | |
327 | */ | |
328 | ||
329 | /* | |
7ba89e62 MD |
330 | * RCU read lock must be held across the next/prev calls to ensure validity of |
331 | * the returned node. | |
dff86257 MD |
332 | */ |
333 | struct rcu_rbtree_node *rcu_rbtree_next(struct rcu_rbtree *rbtree, | |
334 | struct rcu_rbtree_node *x) | |
335 | { | |
269a9ef6 | 336 | struct rcu_rbtree_node *xr, *y; |
7ba89e62 | 337 | unsigned int x_pos; |
dff86257 MD |
338 | |
339 | x = rcu_dereference(x); | |
340 | ||
8ded5fe9 | 341 | if (!rcu_rbtree_is_nil(rbtree, xr = rcu_dereference(x->_right))) |
dff86257 | 342 | return rcu_rbtree_min(rbtree, xr); |
7ba89e62 | 343 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 344 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_RIGHT) { |
dff86257 | 345 | x = y; |
7ba89e62 | 346 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
347 | } |
348 | return y; | |
349 | } | |
350 | ||
351 | struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree *rbtree, | |
352 | struct rcu_rbtree_node *x) | |
353 | { | |
269a9ef6 | 354 | struct rcu_rbtree_node *xl, *y; |
7ba89e62 | 355 | unsigned int x_pos; |
dff86257 MD |
356 | |
357 | x = rcu_dereference(x); | |
358 | ||
8ded5fe9 | 359 | if (!rcu_rbtree_is_nil(rbtree, xl = rcu_dereference(x->_left))) |
4aa30442 | 360 | return rcu_rbtree_max(rbtree, xl); |
7ba89e62 | 361 | y = get_parent_and_pos(x, &x_pos); |
8ded5fe9 | 362 | while (!rcu_rbtree_is_nil(rbtree, y) && x_pos == IS_LEFT) { |
dff86257 | 363 | x = y; |
7ba89e62 | 364 | y = get_parent_and_pos(y, &x_pos); |
dff86257 MD |
365 | } |
366 | return y; | |
367 | } | |
368 | ||
7bc64d1d MD |
369 | /* |
370 | * "node" needs to be non-visible by readers. | |
371 | */ | |
372 | static | |
373 | void populate_node_end(struct rcu_rbtree *rbtree, struct rcu_rbtree_node *node, | |
fcb4eea8 | 374 | unsigned int copy_parents, struct rcu_rbtree_node *stop) |
7bc64d1d MD |
375 | { |
376 | struct rcu_rbtree_node *prev = NULL, *orig_node = node, *top; | |
377 | ||
378 | do { | |
379 | void *max_end; | |
380 | ||
fcb4eea8 | 381 | assert(node); |
7bc64d1d MD |
382 | assert(!rcu_rbtree_is_nil(rbtree, node)); |
383 | max_end = node->end; | |
384 | if (!rcu_rbtree_is_nil(rbtree, node->_right)) | |
385 | max_end = max(max_end, node->_right->max_end); | |
386 | if (!rcu_rbtree_is_nil(rbtree, node->_left)) | |
387 | max_end = max(max_end, node->_left->max_end); | |
388 | ||
389 | if (max_end != node->max_end) { | |
fcb4eea8 | 390 | if (prev && copy_parents) { |
7bc64d1d MD |
391 | node = dup_decay_node(rbtree, node); |
392 | if (get_pos(prev) == IS_RIGHT) | |
393 | node->_right = prev; | |
394 | else | |
395 | node->_left = prev; | |
396 | set_parent(prev, node, get_pos(prev)); | |
397 | } | |
398 | node->max_end = max_end; | |
399 | } else { | |
400 | /* | |
401 | * We did not have to change the current node, | |
402 | * so set the pointer to the prev node. If prev | |
403 | * was null, this means we are coming in the | |
404 | * first loop, and must update the parent of the | |
405 | * node received as parameter (node). | |
406 | */ | |
407 | if (prev) | |
408 | node = prev; | |
409 | top = get_parent(node); | |
410 | cmm_smp_wmb(); /* write into node before publish */ | |
411 | /* make new branch visible to readers */ | |
412 | if (rcu_rbtree_is_nil(rbtree, top)) | |
413 | _CMM_STORE_SHARED(rbtree->root, node); | |
414 | if (get_pos(node) == IS_LEFT) | |
415 | _CMM_STORE_SHARED(top->_left, node); | |
416 | else | |
417 | _CMM_STORE_SHARED(top->_right, node); | |
418 | goto end; | |
419 | } | |
fcb4eea8 MD |
420 | |
421 | /* Check for propagation stop */ | |
422 | if (node == stop) | |
423 | return; | |
424 | ||
7bc64d1d | 425 | prev = node; |
fcb4eea8 MD |
426 | node = get_parent(node); |
427 | } while (!rcu_rbtree_is_nil(rbtree, node)); | |
7bc64d1d MD |
428 | |
429 | top = node; /* nil */ | |
430 | cmm_smp_wmb(); /* write into node before publish */ | |
431 | /* make new branch visible to readers */ | |
432 | _CMM_STORE_SHARED(rbtree->root, prev); | |
433 | ||
434 | end: | |
fcb4eea8 MD |
435 | if (!copy_parents) |
436 | return; | |
7bc64d1d MD |
437 | /* update children */ |
438 | node = orig_node; | |
439 | do { | |
440 | assert(!rcu_rbtree_is_nil(rbtree, node)); | |
441 | set_parent(node->_left, get_decay(get_parent(node->_left)), IS_LEFT); | |
442 | set_parent(node->_right, get_decay(get_parent(node->_right)), IS_RIGHT); | |
443 | } while ((node = get_parent(node)) != top); | |
444 | } | |
445 | ||
dff86257 MD |
446 | /* |
447 | * We have to ensure these assumptions are correct for prev/next | |
448 | * traversal: | |
449 | * | |
450 | * with x being a right child, the assumption that: | |
dca45c9f | 451 | * get_parent(x)->_right == x |
dff86257 | 452 | * or if x is a left child, the assumption that: |
dca45c9f | 453 | * get_parent(x)->_left == x |
dff86257 MD |
454 | * |
455 | * This explains why we have to allocate a vc copy of the node for left_rotate, | |
456 | * right_rotate and transplant operations. | |
457 | * | |
458 | * We always ensure that the right/left child and correct parent is set in the | |
459 | * node copies *before* we reparent the children and make the upper-level point | |
460 | * to the copy. | |
461 | */ | |
462 | ||
463 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
464 | /* Should be eventually followed by a cmm_smp_wmc() */ | |
dff86257 | 465 | |
dbe4ae98 MD |
466 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_LEFT |
467 | ||
dff86257 | 468 | static |
269a9ef6 MD |
469 | void left_rotate(struct rcu_rbtree *rbtree, |
470 | struct rcu_rbtree_node *x) | |
dff86257 | 471 | { |
a84e8c8e | 472 | struct rcu_rbtree_node *y, *y_left; |
dff86257 | 473 | |
dca45c9f MD |
474 | y = x->_right; |
475 | y_left = y->_left; | |
269a9ef6 MD |
476 | |
477 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
478 | x = dup_decay_node(rbtree, x); |
479 | y = dup_decay_node(rbtree, y); | |
480 | y_left = dup_decay_node(rbtree, y_left); | |
269a9ef6 | 481 | |
676dd8b6 | 482 | /* Internal node modifications */ |
7ba89e62 MD |
483 | set_parent(y, get_parent(x), get_pos(x)); |
484 | set_parent(x, y, IS_LEFT); | |
a84e8c8e MD |
485 | set_left(rbtree, y, x); |
486 | set_right(rbtree, x, y_left); | |
dca45c9f | 487 | |
8ded5fe9 | 488 | if (!rcu_rbtree_is_nil(rbtree, y_left)) |
7ba89e62 | 489 | set_parent(y_left, x, IS_RIGHT); |
676dd8b6 MD |
490 | |
491 | cmm_smp_wmb(); /* write into node before publish */ | |
492 | ||
493 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
494 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
495 | _CMM_STORE_SHARED(rbtree->root, y); | |
496 | else if (get_pos(y) == IS_LEFT) | |
497 | _CMM_STORE_SHARED(get_parent(y)->_left, y); | |
676dd8b6 | 498 | else |
a84e8c8e | 499 | _CMM_STORE_SHARED(get_parent(y)->_right, y); |
676dd8b6 | 500 | |
dbe4ae98 | 501 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
502 | set_parent(x->_left, get_decay(get_parent(x->_left)), |
503 | get_pos(x->_left)); | |
504 | set_parent(y->_right, get_decay(get_parent(y->_right)), | |
505 | get_pos(y->_right)); | |
8ded5fe9 | 506 | if (!rcu_rbtree_is_nil(rbtree, y_left)) { |
dca45c9f MD |
507 | set_parent(y_left->_right, |
508 | get_decay(get_parent(y_left->_right)), | |
509 | get_pos(y_left->_right)); | |
510 | set_parent(y_left->_left, | |
511 | get_decay(get_parent(y_left->_left)), | |
512 | get_pos(y_left->_left)); | |
dbe4ae98 | 513 | } |
269a9ef6 MD |
514 | |
515 | /* Sanity checks */ | |
dca45c9f MD |
516 | assert(y == rbtree->root || get_parent(y)->_left == y |
517 | || get_parent(y)->_right == y); | |
518 | assert(x == rbtree->root || get_parent(x)->_left == x | |
519 | || get_parent(x)->_right == x); | |
8ded5fe9 MD |
520 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); |
521 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); | |
522 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
523 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
269a9ef6 MD |
524 | assert(!is_decay(rbtree->root)); |
525 | assert(!is_decay(x)); | |
526 | assert(!is_decay(y)); | |
dca45c9f MD |
527 | assert(!is_decay(x->_right)); |
528 | assert(!is_decay(x->_left)); | |
529 | assert(!is_decay(y->_right)); | |
530 | assert(!is_decay(y->_left)); | |
dff86257 MD |
531 | } |
532 | ||
dbe4ae98 MD |
533 | #else |
534 | ||
535 | /* non-rcu version */ | |
536 | static | |
537 | void left_rotate(struct rcu_rbtree *rbtree, | |
538 | struct rcu_rbtree_node *x) | |
539 | { | |
540 | struct rcu_rbtree_node *y; | |
541 | ||
230dd288 | 542 | lock_test_mutex(); |
dca45c9f MD |
543 | y = x->_right; |
544 | x->_right = y->_left; | |
8ded5fe9 | 545 | if (!rcu_rbtree_is_nil(rbtree, y->_left)) |
dca45c9f | 546 | set_parent(y->_left, x, IS_RIGHT); |
7ba89e62 | 547 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 548 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
dbe4ae98 | 549 | rbtree->root = y; |
dca45c9f MD |
550 | else if (x == get_parent(x)->_left) { |
551 | get_parent(x)->_left = y; | |
dbe4ae98 | 552 | } else { |
dca45c9f | 553 | get_parent(x)->_right = y; |
dbe4ae98 | 554 | } |
dca45c9f | 555 | y->_left = x; |
7ba89e62 | 556 | set_parent(x, y, IS_LEFT); |
230dd288 | 557 | unlock_test_mutex(); |
dbe4ae98 MD |
558 | } |
559 | ||
560 | #endif | |
561 | ||
562 | #ifdef RBTREE_RCU_SUPPORT_ROTATE_RIGHT | |
dff86257 | 563 | static |
269a9ef6 MD |
564 | void right_rotate(struct rcu_rbtree *rbtree, |
565 | struct rcu_rbtree_node *x) | |
dff86257 | 566 | { |
a84e8c8e | 567 | struct rcu_rbtree_node *y, *y_right; |
dff86257 | 568 | |
dca45c9f MD |
569 | y = x->_left; |
570 | y_right = y->_right; | |
269a9ef6 MD |
571 | |
572 | /* Now operate on new copy, decay old versions */ | |
dbe4ae98 MD |
573 | x = dup_decay_node(rbtree, x); |
574 | y = dup_decay_node(rbtree, y); | |
575 | y_right = dup_decay_node(rbtree, y_right); | |
269a9ef6 | 576 | |
676dd8b6 | 577 | /* Internal node modifications */ |
7ba89e62 MD |
578 | set_parent(y, get_parent(x), get_pos(x)); |
579 | set_parent(x, y, IS_RIGHT); | |
a84e8c8e MD |
580 | set_right(rbtree, y, x); |
581 | set_left(rbtree, x, y_right); | |
dca45c9f | 582 | |
8ded5fe9 | 583 | if (!rcu_rbtree_is_nil(rbtree, y_right)) |
7ba89e62 | 584 | set_parent(y_right, x, IS_LEFT); |
676dd8b6 MD |
585 | |
586 | cmm_smp_wmb(); /* write into node before publish */ | |
587 | ||
588 | /* External references update (visible by readers) */ | |
a84e8c8e MD |
589 | if (rcu_rbtree_is_nil(rbtree, get_parent(y))) |
590 | _CMM_STORE_SHARED(rbtree->root, y); | |
591 | else if (get_pos(y) == IS_RIGHT) | |
592 | _CMM_STORE_SHARED(get_parent(y)->_right, y); | |
676dd8b6 | 593 | else |
a84e8c8e | 594 | _CMM_STORE_SHARED(get_parent(y)->_left, y); |
676dd8b6 | 595 | |
dbe4ae98 | 596 | /* Point children to new copy (parent only used by updates/next/prev) */ |
dca45c9f MD |
597 | set_parent(x->_right, get_decay(get_parent(x->_right)), |
598 | get_pos(x->_right)); | |
599 | set_parent(y->_left, get_decay(get_parent(y->_left)), | |
600 | get_pos(y->_left)); | |
8ded5fe9 | 601 | if (!rcu_rbtree_is_nil(rbtree, y_right)) { |
dca45c9f MD |
602 | set_parent(y_right->_left, |
603 | get_decay(get_parent(y_right->_left)), | |
604 | get_pos(y_right->_left)); | |
605 | set_parent(y_right->_right, | |
606 | get_decay(get_parent(y_right->_right)), | |
607 | get_pos(y_right->_right)); | |
dbe4ae98 | 608 | } |
269a9ef6 MD |
609 | |
610 | /* Sanity checks */ | |
dca45c9f MD |
611 | assert(y == rbtree->root || get_parent(y)->_right == y |
612 | || get_parent(y)->_left == y); | |
613 | assert(x == rbtree->root || get_parent(x)->_right == x | |
614 | || get_parent(x)->_left == x); | |
8ded5fe9 MD |
615 | assert(rcu_rbtree_is_nil(rbtree, x->_left) || get_parent(x->_left) == x); |
616 | assert(rcu_rbtree_is_nil(rbtree, x->_right) || get_parent(x->_right) == x); | |
617 | assert(rcu_rbtree_is_nil(rbtree, y->_left) || get_parent(y->_left) == y); | |
618 | assert(rcu_rbtree_is_nil(rbtree, y->_right) || get_parent(y->_right) == y); | |
269a9ef6 MD |
619 | assert(!is_decay(rbtree->root)); |
620 | assert(!is_decay(x)); | |
621 | assert(!is_decay(y)); | |
dca45c9f MD |
622 | assert(!is_decay(x->_left)); |
623 | assert(!is_decay(x->_right)); | |
624 | assert(!is_decay(y->_left)); | |
625 | assert(!is_decay(y->_right)); | |
dff86257 MD |
626 | } |
627 | ||
6daf6090 MD |
628 | #else |
629 | ||
dbe4ae98 | 630 | /* non-rcu version */ |
6daf6090 MD |
631 | static |
632 | void right_rotate(struct rcu_rbtree *rbtree, | |
633 | struct rcu_rbtree_node *x) | |
634 | { | |
635 | struct rcu_rbtree_node *y; | |
636 | ||
230dd288 | 637 | lock_test_mutex(); |
dca45c9f MD |
638 | y = x->_left; |
639 | x->_left = y->_right; | |
8ded5fe9 | 640 | if (!rcu_rbtree_is_nil(rbtree, y->_right)) |
dca45c9f | 641 | set_parent(y->_right, x, IS_LEFT); |
7ba89e62 | 642 | set_parent(y, get_parent(x), get_pos(x)); |
8ded5fe9 | 643 | if (rcu_rbtree_is_nil(rbtree, get_parent(x))) |
6daf6090 | 644 | rbtree->root = y; |
dca45c9f MD |
645 | else if (x == get_parent(x)->_right) { |
646 | get_parent(x)->_right = y; | |
6daf6090 | 647 | } else { |
dca45c9f | 648 | get_parent(x)->_left = y; |
6daf6090 | 649 | } |
dca45c9f | 650 | y->_right = x; |
7ba89e62 | 651 | set_parent(x, y, IS_RIGHT); |
230dd288 | 652 | unlock_test_mutex(); |
6daf6090 MD |
653 | } |
654 | ||
655 | #endif | |
656 | ||
dff86257 MD |
657 | static void rcu_rbtree_insert_fixup(struct rcu_rbtree *rbtree, |
658 | struct rcu_rbtree_node *z) | |
659 | { | |
660 | struct rcu_rbtree_node *y; | |
661 | ||
3366b9c0 | 662 | dbg_printf("insert fixup %p\n", z->begin); |
269a9ef6 | 663 | assert(!is_decay(rbtree->root)); |
dff86257 | 664 | |
7ba89e62 | 665 | while (get_parent(z)->color == COLOR_RED) { |
dca45c9f MD |
666 | if (get_parent(z) == get_parent(get_parent(z))->_left) { |
667 | y = get_parent(get_parent(z))->_right; | |
dff86257 | 668 | if (y->color == COLOR_RED) { |
7ba89e62 | 669 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 670 | y->color = COLOR_BLACK; |
7ba89e62 MD |
671 | get_parent(get_parent(z))->color = COLOR_RED; |
672 | z = get_parent(get_parent(z)); | |
dff86257 | 673 | } else { |
dca45c9f | 674 | if (z == get_parent(z)->_right) { |
7ba89e62 | 675 | z = get_parent(z); |
dff86257 | 676 | left_rotate(rbtree, z); |
269a9ef6 MD |
677 | z = get_decay(z); |
678 | assert(!is_decay(rbtree->root)); | |
dff86257 | 679 | } |
7ba89e62 MD |
680 | get_parent(z)->color = COLOR_BLACK; |
681 | get_parent(get_parent(z))->color = COLOR_RED; | |
269a9ef6 | 682 | assert(!is_decay(z)); |
7ba89e62 MD |
683 | assert(!is_decay(get_parent(z))); |
684 | assert(!is_decay(get_parent(get_parent(z)))); | |
685 | right_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
686 | assert(!is_decay(z)); |
687 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
688 | } |
689 | } else { | |
dca45c9f | 690 | y = get_parent(get_parent(z))->_left; |
dff86257 | 691 | if (y->color == COLOR_RED) { |
7ba89e62 | 692 | get_parent(z)->color = COLOR_BLACK; |
dff86257 | 693 | y->color = COLOR_BLACK; |
7ba89e62 MD |
694 | get_parent(get_parent(z))->color = COLOR_RED; |
695 | z = get_parent(get_parent(z)); | |
dff86257 | 696 | } else { |
dca45c9f | 697 | if (z == get_parent(z)->_left) { |
7ba89e62 | 698 | z = get_parent(z); |
dff86257 | 699 | right_rotate(rbtree, z); |
269a9ef6 MD |
700 | z = get_decay(z); |
701 | assert(!is_decay(rbtree->root)); | |
dff86257 | 702 | } |
7ba89e62 MD |
703 | get_parent(z)->color = COLOR_BLACK; |
704 | get_parent(get_parent(z))->color = COLOR_RED; | |
705 | left_rotate(rbtree, get_parent(get_parent(z))); | |
269a9ef6 MD |
706 | assert(!is_decay(z)); |
707 | assert(!is_decay(rbtree->root)); | |
dff86257 MD |
708 | } |
709 | } | |
710 | } | |
711 | rbtree->root->color = COLOR_BLACK; | |
712 | } | |
713 | ||
714 | /* | |
715 | * rcu_rbtree_insert - Insert a node in the RCU rbtree | |
716 | * | |
717 | * Returns 0 on success, or < 0 on error. | |
718 | */ | |
719 | int rcu_rbtree_insert(struct rcu_rbtree *rbtree, | |
720 | struct rcu_rbtree_node *z) | |
721 | { | |
a84e8c8e | 722 | struct rcu_rbtree_node *x, *y; |
dff86257 | 723 | |
3366b9c0 | 724 | dbg_printf("insert %p\n", z->begin); |
269a9ef6 | 725 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
726 | |
727 | y = make_nil(rbtree); | |
dff86257 | 728 | x = rbtree->root; |
8ded5fe9 | 729 | while (!rcu_rbtree_is_nil(rbtree, x)) { |
dff86257 | 730 | y = x; |
3366b9c0 | 731 | if (rbtree->comp(z->begin, x->begin) < 0) |
dca45c9f | 732 | x = x->_left; |
dff86257 | 733 | else |
dca45c9f | 734 | x = x->_right; |
dff86257 MD |
735 | } |
736 | ||
dca45c9f MD |
737 | z->_left = make_nil(rbtree); |
738 | z->_right = make_nil(rbtree); | |
dff86257 | 739 | z->color = COLOR_RED; |
269a9ef6 | 740 | z->decay_next = NULL; |
55b5e812 | 741 | z->max_end = z->end; |
dff86257 | 742 | |
8ded5fe9 | 743 | if (rcu_rbtree_is_nil(rbtree, y)) { |
7bc64d1d | 744 | set_parent(z, y, IS_RIGHT); /* pos arbitrary for root node */ |
0bd215cc MD |
745 | /* |
746 | * Order stores to z (children/parents) before stores | |
747 | * that will make it visible to the rest of the tree. | |
748 | */ | |
749 | cmm_smp_wmb(); | |
dff86257 | 750 | _CMM_STORE_SHARED(rbtree->root, z); |
3366b9c0 | 751 | } else if (rbtree->comp(z->begin, y->begin) < 0) { |
7bc64d1d MD |
752 | y = dup_decay_node(rbtree, y); |
753 | set_parent(z, y, IS_LEFT); | |
754 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 755 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 756 | else |
a84e8c8e | 757 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 758 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 759 | } else { |
7bc64d1d MD |
760 | y = dup_decay_node(rbtree, y); |
761 | set_parent(z, y, IS_RIGHT); | |
762 | if (get_pos(z) == IS_LEFT) | |
a84e8c8e | 763 | _CMM_STORE_SHARED(y->_left, z); |
dca45c9f | 764 | else |
a84e8c8e | 765 | _CMM_STORE_SHARED(y->_right, z); |
fcb4eea8 | 766 | populate_node_end(rbtree, y, 1, NULL); |
dca45c9f | 767 | } |
dff86257 MD |
768 | rcu_rbtree_insert_fixup(rbtree, z); |
769 | /* | |
770 | * Make sure to commit all _CMM_STORE_SHARED() for non-coherent caches. | |
771 | */ | |
772 | cmm_smp_wmc(); | |
773 | show_tree(rbtree); | |
774 | ||
775 | return 0; | |
776 | } | |
777 | ||
778 | /* | |
779 | * Transplant v into u position. | |
dff86257 | 780 | */ |
6daf6090 MD |
781 | |
782 | #ifdef RBTREE_RCU_SUPPORT_TRANSPLANT | |
783 | ||
269a9ef6 MD |
784 | static |
785 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
786 | struct rcu_rbtree_node *u, | |
dca45c9f | 787 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
788 | unsigned int copy_parents, |
789 | struct rcu_rbtree_node *stop) | |
dff86257 | 790 | { |
3366b9c0 | 791 | dbg_printf("transplant %p\n", v->begin); |
dff86257 | 792 | |
8ded5fe9 | 793 | if (!rcu_rbtree_is_nil(rbtree, v)) |
dbe4ae98 | 794 | v = dup_decay_node(rbtree, v); |
c479601c | 795 | |
8ded5fe9 | 796 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) { |
7ba89e62 MD |
797 | /* pos is arbitrary for root node */ |
798 | set_parent(v, get_parent(u), IS_RIGHT); | |
c479601c MD |
799 | cmm_smp_wmb(); /* write into node before publish */ |
800 | _CMM_STORE_SHARED(rbtree->root, v); | |
dff86257 | 801 | } else { |
fcb4eea8 MD |
802 | struct rcu_rbtree_node *vp; |
803 | ||
804 | vp = get_parent(u); | |
805 | if (copy_parents) | |
806 | vp = dup_decay_node(rbtree, vp); | |
807 | set_parent(v, vp, get_pos(u)); | |
808 | if (get_pos(v) == IS_LEFT) | |
809 | _CMM_STORE_SHARED(vp->_left, v); | |
806967f3 | 810 | else |
fcb4eea8 MD |
811 | _CMM_STORE_SHARED(vp->_right, v); |
812 | populate_node_end(rbtree, vp, copy_parents, stop); | |
c479601c | 813 | } |
806967f3 | 814 | |
dbe4ae98 | 815 | /* Point children to new copy (parent only used by updates/next/prev) */ |
8ded5fe9 | 816 | if (!rcu_rbtree_is_nil(rbtree, v)) { |
dca45c9f MD |
817 | set_parent(v->_right, get_decay(get_parent(v->_right)), |
818 | get_pos(v->_right)); | |
819 | set_parent(v->_left, get_decay(get_parent(v->_left)), | |
820 | get_pos(v->_left)); | |
dff86257 | 821 | } |
269a9ef6 | 822 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
823 | } |
824 | ||
6daf6090 MD |
825 | #else |
826 | ||
827 | /* Non-RCU version */ | |
828 | static | |
829 | void rcu_rbtree_transplant(struct rcu_rbtree *rbtree, | |
830 | struct rcu_rbtree_node *u, | |
dca45c9f | 831 | struct rcu_rbtree_node *v, |
fcb4eea8 MD |
832 | unsigned int copy_parents, |
833 | struct rcu_rbtree_node *stop) | |
6daf6090 | 834 | { |
3366b9c0 | 835 | dbg_printf("transplant %p\n", v->begin); |
6daf6090 | 836 | |
230dd288 | 837 | lock_test_mutex(); |
8ded5fe9 | 838 | if (rcu_rbtree_is_nil(rbtree, get_parent(u))) |
6daf6090 | 839 | rbtree->root = v; |
dca45c9f MD |
840 | else if (u == get_parent(u)->_left) |
841 | get_parent(u)->_left = v; | |
7ba89e62 | 842 | else |
dca45c9f | 843 | get_parent(u)->_right = v; |
7ba89e62 | 844 | set_parent(v, get_parent(u), get_pos(u)); |
230dd288 | 845 | unlock_test_mutex(); |
6daf6090 MD |
846 | } |
847 | ||
848 | #endif | |
849 | ||
dff86257 MD |
850 | static void rcu_rbtree_remove_fixup(struct rcu_rbtree *rbtree, |
851 | struct rcu_rbtree_node *x) | |
852 | { | |
3366b9c0 | 853 | dbg_printf("remove fixup %p\n", x->begin); |
dff86257 MD |
854 | |
855 | while (x != rbtree->root && x->color == COLOR_BLACK) { | |
7ba89e62 | 856 | assert(!is_decay(get_parent(x))); |
dca45c9f MD |
857 | assert(!is_decay(get_parent(x)->_left)); |
858 | if (x == get_parent(x)->_left) { | |
269a9ef6 | 859 | struct rcu_rbtree_node *w; |
dff86257 | 860 | |
dca45c9f | 861 | w = get_parent(x)->_right; |
dff86257 MD |
862 | |
863 | if (w->color == COLOR_RED) { | |
269a9ef6 | 864 | w->color = COLOR_BLACK; |
7ba89e62 MD |
865 | get_parent(x)->color = COLOR_RED; |
866 | left_rotate(rbtree, get_parent(x)); | |
269a9ef6 MD |
867 | x = get_decay(x); |
868 | assert(!is_decay(rbtree->root)); | |
dca45c9f | 869 | w = get_parent(x)->_right; |
dff86257 | 870 | } |
dca45c9f MD |
871 | if (w->_left->color == COLOR_BLACK |
872 | && w->_right->color == COLOR_BLACK) { | |
dff86257 | 873 | w->color = COLOR_RED; |
7ba89e62 | 874 | x = get_parent(x); |
c479601c MD |
875 | assert(!is_decay(rbtree->root)); |
876 | assert(!is_decay(x)); | |
dff86257 | 877 | } else { |
dca45c9f MD |
878 | if (w->_right->color == COLOR_BLACK) { |
879 | w->_left->color = COLOR_BLACK; | |
dff86257 MD |
880 | w->color = COLOR_RED; |
881 | right_rotate(rbtree, w); | |
c479601c | 882 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 883 | x = get_decay(x); |
dca45c9f | 884 | w = get_parent(x)->_right; |
dff86257 | 885 | } |
7ba89e62 MD |
886 | w->color = get_parent(x)->color; |
887 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 888 | w->_right->color = COLOR_BLACK; |
7ba89e62 | 889 | left_rotate(rbtree, get_parent(x)); |
269a9ef6 | 890 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
891 | x = rbtree->root; |
892 | } | |
893 | } else { | |
269a9ef6 | 894 | struct rcu_rbtree_node *w; |
dff86257 | 895 | |
dca45c9f | 896 | w = get_parent(x)->_left; |
dff86257 MD |
897 | |
898 | if (w->color == COLOR_RED) { | |
269a9ef6 | 899 | w->color = COLOR_BLACK; |
7ba89e62 MD |
900 | get_parent(x)->color = COLOR_RED; |
901 | right_rotate(rbtree, get_parent(x)); | |
c479601c | 902 | assert(!is_decay(rbtree->root)); |
269a9ef6 | 903 | x = get_decay(x); |
dca45c9f | 904 | w = get_parent(x)->_left; |
dff86257 | 905 | } |
dca45c9f MD |
906 | if (w->_right->color == COLOR_BLACK |
907 | && w->_left->color == COLOR_BLACK) { | |
dff86257 | 908 | w->color = COLOR_RED; |
7ba89e62 | 909 | x = get_parent(x); |
c479601c MD |
910 | assert(!is_decay(rbtree->root)); |
911 | assert(!is_decay(x)); | |
dff86257 | 912 | } else { |
dca45c9f MD |
913 | if (w->_left->color == COLOR_BLACK) { |
914 | w->_right->color = COLOR_BLACK; | |
dff86257 MD |
915 | w->color = COLOR_RED; |
916 | left_rotate(rbtree, w); | |
269a9ef6 MD |
917 | assert(!is_decay(rbtree->root)); |
918 | x = get_decay(x); | |
dca45c9f | 919 | w = get_parent(x)->_left; |
dff86257 | 920 | } |
7ba89e62 MD |
921 | w->color = get_parent(x)->color; |
922 | get_parent(x)->color = COLOR_BLACK; | |
dca45c9f | 923 | w->_left->color = COLOR_BLACK; |
7ba89e62 | 924 | right_rotate(rbtree, get_parent(x)); |
c479601c | 925 | assert(!is_decay(rbtree->root)); |
dff86257 MD |
926 | x = rbtree->root; |
927 | } | |
928 | } | |
929 | } | |
930 | x->color = COLOR_BLACK; | |
931 | } | |
932 | ||
933 | /* | |
269a9ef6 MD |
934 | * Delete z. All non-copied children left/right positions are unchanged. |
935 | */ | |
936 | static | |
937 | void rcu_rbtree_remove_nonil(struct rcu_rbtree *rbtree, | |
938 | struct rcu_rbtree_node *z, | |
939 | struct rcu_rbtree_node *y) | |
dff86257 | 940 | { |
a84e8c8e | 941 | struct rcu_rbtree_node *x; |
dff86257 | 942 | |
3366b9c0 | 943 | dbg_printf("remove nonil %p\n", z->begin); |
dff86257 MD |
944 | show_tree(rbtree); |
945 | ||
c479601c MD |
946 | assert(!is_decay(z)); |
947 | assert(!is_decay(y)); | |
dca45c9f | 948 | assert(!is_decay(y->_right)); |
7ba89e62 | 949 | assert(!is_decay(get_parent(y))); |
dca45c9f | 950 | x = y->_right; |
c479601c | 951 | assert(!is_decay(x)); |
7ba89e62 | 952 | if (get_parent(y) == z) { |
230dd288 | 953 | y = dup_decay_node(rbtree, y); |
7ba89e62 | 954 | set_parent(x, y, get_pos(x)); /* parent for nil */ |
dca45c9f | 955 | /* y is z's right node: set left will just update y */ |
a84e8c8e | 956 | set_left(rbtree, y, z->_left); |
fcb4eea8 | 957 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); |
230dd288 MD |
958 | } else { |
959 | struct rcu_rbtree_node *oy_right, *z_right; | |
960 | ||
961 | /* | |
962 | * Need to make sure y is always visible by readers. | |
963 | */ | |
dca45c9f | 964 | y = rcu_rbtree_min_dup_decay(rbtree, z->_right, &z_right); |
269a9ef6 MD |
965 | assert(!is_decay(y)); |
966 | assert(!is_decay(z)); | |
dca45c9f MD |
967 | oy_right = y->_right; |
968 | ||
969 | /* | |
3366b9c0 | 970 | * The max child begin of z_right does not change, because |
dca45c9f MD |
971 | * we're only changing its left children. |
972 | */ | |
973 | y->_right = z_right; | |
974 | set_parent(y->_right, y, IS_RIGHT); | |
dca45c9f MD |
975 | assert(!is_decay(z->_left)); |
976 | y->_left = z->_left; | |
230dd288 | 977 | assert(!is_decay(oy_right)); |
dca45c9f MD |
978 | /* |
979 | * Transplant of oy_right to old y's location will only | |
fcb4eea8 | 980 | * trigger a "end" value update of the already copied branch |
dca45c9f MD |
981 | * (which is not visible yet). We are transplanting |
982 | * oy_right as a left child of old y's parent, so the | |
983 | * min values update propagated upward necessarily stops | |
984 | * at z_right. | |
985 | */ | |
fcb4eea8 MD |
986 | rcu_rbtree_transplant(rbtree, y, oy_right, 0, y); |
987 | rcu_rbtree_transplant(rbtree, z, y, 1, NULL); | |
230dd288 | 988 | /* Update children */ |
dca45c9f | 989 | (void) rcu_rbtree_min_update_decay(rbtree, y->_right); |
dff86257 | 990 | } |
c479601c | 991 | y = get_decay(y); |
269a9ef6 | 992 | assert(!is_decay(z)); |
dca45c9f | 993 | assert(!is_decay(z->_left)); |
dff86257 | 994 | y->color = z->color; |
dca45c9f MD |
995 | set_parent(y->_left, y, IS_LEFT); |
996 | set_parent(y->_right, get_decay(get_parent(y->_right)), IS_RIGHT); | |
997 | assert(!is_decay(y->_left)); | |
998 | assert(!is_decay(y->_right)); | |
dff86257 MD |
999 | } |
1000 | ||
1001 | int rcu_rbtree_remove(struct rcu_rbtree *rbtree, | |
1002 | struct rcu_rbtree_node *z) | |
1003 | { | |
1004 | struct rcu_rbtree_node *x, *y; | |
1005 | unsigned int y_original_color; | |
1006 | ||
269a9ef6 | 1007 | assert(!is_decay(rbtree->root)); |
3366b9c0 | 1008 | dbg_printf("remove %p\n", z->begin); |
dff86257 MD |
1009 | show_tree(rbtree); |
1010 | ||
c479601c | 1011 | assert(!is_decay(z)); |
dff86257 MD |
1012 | y = z; |
1013 | y_original_color = y->color; | |
1014 | ||
8ded5fe9 | 1015 | if (rcu_rbtree_is_nil(rbtree, z->_left)) { |
fcb4eea8 | 1016 | rcu_rbtree_transplant(rbtree, z, z->_right, 1, NULL); |
269a9ef6 | 1017 | assert(!is_decay(z)); |
dca45c9f | 1018 | x = get_decay(z->_right); |
dff86257 | 1019 | show_tree(rbtree); |
8ded5fe9 | 1020 | } else if (rcu_rbtree_is_nil(rbtree, z->_right)) { |
fcb4eea8 | 1021 | rcu_rbtree_transplant(rbtree, z, z->_left, 1, NULL); |
269a9ef6 | 1022 | assert(!is_decay(z)); |
dca45c9f | 1023 | x = get_decay(z->_left); |
dff86257 MD |
1024 | show_tree(rbtree); |
1025 | } else { | |
dca45c9f | 1026 | y = rcu_rbtree_min(rbtree, z->_right); |
c479601c | 1027 | assert(!is_decay(y)); |
dff86257 | 1028 | y_original_color = y->color; |
dca45c9f | 1029 | x = y->_right; |
269a9ef6 | 1030 | rcu_rbtree_remove_nonil(rbtree, z, y); |
6daf6090 | 1031 | x = get_decay(x); |
dff86257 MD |
1032 | show_tree(rbtree); |
1033 | } | |
1034 | if (y_original_color == COLOR_BLACK) | |
1035 | rcu_rbtree_remove_fixup(rbtree, x); | |
1036 | show_tree(rbtree); | |
1037 | /* | |
1038 | * Commit all _CMM_STORE_SHARED(). | |
1039 | */ | |
1040 | cmm_smp_wmc(); | |
1041 | ||
1042 | return 0; | |
1043 | } |