Commit | Line | Data |
---|---|---|
00131368 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 | ||
36 | #include <urcu-rbtree.h> | |
37 | #include <urcu-pointer.h> | |
38 | ||
39 | /* | |
40 | * TODO | |
41 | * Deal with memory allocation errors. | |
42 | * Can be ensured by reserving a pool of memory entries before doing the | |
43 | * insertion, which will have to be function of number of | |
44 | * transplantations/rotations required for the operation. | |
45 | */ | |
46 | ||
47 | /* Sentinel (bottom nodes). Don't care about p, left, right and key values */ | |
db5b1669 | 48 | struct rcu_rbtree_node rcu_rbtree_nil = { |
00131368 MD |
49 | .color = COLOR_BLACK, |
50 | }; | |
51 | ||
52 | /* | |
53 | * Iterative rbtree search. | |
54 | */ | |
55 | struct rcu_rbtree_node* rcu_rbtree_search(struct rcu_rbtree_node *x, | |
56 | void *k, rcu_rbtree_comp comp) | |
57 | { | |
58 | x = rcu_dereference(x); | |
59 | ||
60 | while (x != NULL && k != x->key) { | |
61 | if (k < x->key) | |
62 | x = rcu_dereference(x->left); | |
63 | else | |
64 | x = rcu_dereference(x->right); | |
65 | } | |
66 | return x; | |
67 | } | |
68 | ||
69 | struct rcu_rbtree_node *rcu_rbtree_min(struct rcu_rbtree_node *x, | |
70 | rcu_rbtree_comp comp) | |
71 | { | |
72 | struct rcu_rbtree_node *xl; | |
73 | ||
74 | x = rcu_dereference(x); | |
75 | ||
76 | while ((xl = rcu_dereference(x->left)) != NULL) | |
77 | x = xl; | |
78 | return x; | |
79 | } | |
80 | ||
81 | struct rcu_rbtree_node *rcu_rbtree_max(struct rcu_rbtree_node *x, | |
82 | rcu_rbtree_comp comp) | |
83 | { | |
84 | struct rcu_rbtree_node *xr; | |
85 | ||
86 | x = rcu_dereference(x); | |
87 | ||
88 | while ((xr = rcu_dereference(x->right)) != NULL) | |
89 | x = xr; | |
90 | return x; | |
91 | } | |
92 | ||
93 | /* | |
94 | * next and prev need to have mutex held to ensure that parent pointer is | |
95 | * coherent. | |
96 | */ | |
97 | struct rcu_rbtree_node *rcu_rbtree_next(struct rcu_rbtree_node *x, | |
98 | rcu_rbtree_comp comp) | |
99 | { | |
100 | struct rcu_rbtree_node *xr, *y; | |
101 | ||
102 | x = rcu_dereference(x); | |
103 | ||
104 | if ((xr = rcu_dereference(x->right)) != NULL) | |
105 | return rcu_rbtree_min(xr, comp); | |
106 | y = rcu_dereference(x->p); | |
107 | while (y != NULL && x == rcu_dereference(y->right)) { | |
108 | x = y; | |
109 | y = rcu_dereference(y->p); | |
110 | } | |
111 | return y; | |
112 | } | |
113 | ||
114 | struct rcu_rbtree_node *rcu_rbtree_prev(struct rcu_rbtree_node *x, | |
115 | rcu_rbtree_comp comp) | |
116 | { | |
117 | struct rcu_rbtree_node *xl, *y; | |
118 | ||
119 | x = rcu_dereference(x); | |
120 | ||
121 | if ((xl = rcu_dereference(x->left)) != NULL) | |
122 | return rcu_rbtree_max(xl, comp); | |
123 | y = rcu_dereference(x->p); | |
124 | while (y != NULL && x == rcu_dereference(y->left)) { | |
125 | x = y; | |
126 | y = rcu_dereference(y->p); | |
127 | } | |
128 | return y; | |
129 | } | |
130 | ||
131 | /* | |
132 | * We have to ensure these assumptions are correct for prev/next | |
133 | * traversal: | |
134 | * | |
135 | * with x being a right child, the assumption that: | |
136 | * x->p->right == x | |
137 | * or if x is a left child, the assumption that: | |
138 | * x->p->left == x | |
139 | * | |
140 | * This explains why we have to allocate a vc copy of the node for left_rotate, | |
141 | * right_rotate and transplant operations. | |
142 | * | |
143 | * We always ensure that the right/left child and correct parent is set in the | |
144 | * node copies *before* we reparent the children and make the upper-level point | |
145 | * to the copy. | |
146 | */ | |
147 | ||
148 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
149 | /* Should be eventually followed by a smp_wmc() */ | |
150 | /* Returns the new x. Previous x->right references are changed to yc. */ | |
151 | static struct rcu_rbtree_node *left_rotate(struct rcu_rbtree_node **root, | |
152 | struct rcu_rbtree_node *x, | |
153 | rcu_rbtree_alloc rballoc, | |
154 | rcu_rbtree_free rbfree) | |
155 | { | |
156 | struct rcu_rbtree_node *xc, *y, *yc; | |
157 | ||
158 | y = x->right; | |
159 | ||
160 | yc = rballoc(); | |
161 | xc = rballoc(); | |
162 | *xc = *x; | |
163 | *yc = *y; | |
164 | ||
165 | /* Modify children and parents in the node copies */ | |
166 | xc->right = y->left; | |
167 | xc->p = yc; | |
168 | yc->left = xc; | |
169 | yc->p = x->p; | |
170 | ||
171 | /* | |
172 | * Order stores to node copies (children/parents) before stores that | |
173 | * will make the copies visible to the rest of the tree. | |
174 | */ | |
175 | smp_wmb(); | |
176 | ||
177 | /* Make parents point to the copies */ | |
db5b1669 | 178 | if (x->p == &rcu_rbtree_nil) |
00131368 MD |
179 | _STORE_SHARED(*root, yc); |
180 | else if (x == x->p->left) | |
181 | _STORE_SHARED(x->p->left, yc); | |
182 | else | |
183 | _STORE_SHARED(x->p->right, yc); | |
184 | ||
185 | /* Assign children parents to copies */ | |
186 | _STORE_SHARED(xc->right->p, xc); | |
187 | _STORE_SHARED(xc->left->p, xc); | |
188 | _STORE_SHARED(yc->right->p, yc); | |
189 | /* yc->left is xc, its parent is already set in node copy */ | |
190 | ||
191 | defer_rcu(rbfree, x); | |
192 | defer_rcu(rbfree, y); | |
193 | return xc; | |
194 | } | |
195 | ||
196 | #if 0 /* orig */ | |
197 | static void left_rotate(struct rcu_rbtree_node **root, | |
198 | struct rcu_rbtree_node *x, | |
199 | rcu_rbtree_alloc rballoc) | |
200 | { | |
201 | struct rcu_rbtree_node *y; | |
202 | ||
203 | y = x->right; | |
204 | x->right = y->left; | |
db5b1669 | 205 | if (y->left != &rcu_rbtree_nil) |
00131368 MD |
206 | y->left->p = x; |
207 | y->p = x->p; | |
db5b1669 | 208 | if (x->p == &rcu_rbtree_nil) |
00131368 MD |
209 | *root = y; |
210 | else if (x == x->p->left) | |
211 | x->p->left = y; | |
212 | else | |
213 | x->p->right = y; | |
214 | y->left = x; | |
215 | x->p = y; | |
216 | } | |
217 | #endif //0 | |
218 | ||
219 | /* RCU: copy x and y, atomically point to new versions. GC old. */ | |
220 | /* Should be eventually followed by a smp_wmc() */ | |
221 | /* Returns the new x. Previous x->left references are changed to yc. */ | |
222 | static struct rcu_rbtree_node *right_rotate(struct rcu_rbtree_node **root, | |
223 | struct rcu_rbtree_node *x, | |
224 | rcu_rbtree_alloc rballoc, | |
225 | rcu_rbtree_free rbfree) | |
226 | { | |
227 | struct rcu_rbtree_node *xc, *y, *yc; | |
228 | ||
229 | y = x->left; | |
230 | ||
231 | yc = rballoc(); | |
232 | xc = rballoc(); | |
233 | *xc = *x; | |
234 | *yc = *y; | |
235 | ||
236 | /* Modify children and parents in the node copies */ | |
237 | xc->left = y->right; | |
238 | xc->p = yc; | |
239 | yc->right = xc; | |
240 | yc->p = x->p; | |
241 | ||
242 | /* | |
243 | * Order stores to node copies (children/parents) before stores that | |
244 | * will make the copies visible to the rest of the tree. | |
245 | */ | |
246 | smp_wmb(); | |
247 | ||
248 | /* Make parents point to the copies */ | |
db5b1669 | 249 | if (x->p == &rcu_rbtree_nil) |
00131368 MD |
250 | _STORE_SHARED(*root, yc); |
251 | else if (x == x->p->right) | |
252 | _STORE_SHARED(x->p->right, yc); | |
253 | else | |
254 | _STORE_SHARED(x->p->left, yc); | |
255 | ||
256 | /* Assign children parents to copies */ | |
257 | _STORE_SHARED(xc->left->p, xc); | |
258 | _STORE_SHARED(xc->right->p, xc); | |
259 | _STORE_SHARED(yc->left->p, yc); | |
260 | /* yc->right is xc, its parent is already set in node copy */ | |
261 | ||
262 | defer_rcu(rbfree, x); | |
263 | defer_rcu(rbfree, y); | |
264 | return xc; | |
265 | } | |
266 | ||
267 | #if 0 //orig | |
268 | static void right_rotate(struct rcu_rbtree_node **root, | |
269 | struct rcu_rbtree_node *x, | |
270 | rcu_rbtree_alloc rballoc) | |
271 | { | |
272 | struct rcu_rbtree_node *y; | |
273 | ||
274 | y = x->left; | |
275 | x->left = y->right; | |
db5b1669 | 276 | if (y->right != &rcu_rbtree_nil) |
00131368 MD |
277 | y->right->p = x; |
278 | y->p = x->p; | |
db5b1669 | 279 | if (x->p == &rcu_rbtree_nil) |
00131368 MD |
280 | *root = y; |
281 | else if (x == x->p->right) | |
282 | x->p->right = y; | |
283 | else | |
284 | x->p->left = y; | |
285 | y->right = x; | |
286 | x->p = y; | |
287 | } | |
288 | #endif //0 | |
289 | ||
290 | static void rcu_rbtree_insert_fixup(struct rcu_rbtree_node **root, | |
291 | struct rcu_rbtree_node *z, | |
292 | rcu_rbtree_alloc rballoc, | |
293 | rcu_rbtree_free rbfree) | |
294 | { | |
295 | struct rcu_rbtree_node *y; | |
296 | ||
297 | while (z->p->color == COLOR_RED) { | |
298 | if (z->p == z->p->p->left) { | |
299 | y = z->p->p->right; | |
300 | if (y->color == COLOR_RED) { | |
301 | z->p->color = COLOR_BLACK; | |
302 | y->color = COLOR_BLACK; | |
303 | z->p->p->color = COLOR_RED; | |
304 | z = z->p->p; | |
305 | } else { | |
306 | if (z == z->p->right) { | |
307 | z = z->p; | |
308 | z = left_rotate(root, z, | |
309 | rballoc, rbfree); | |
310 | } | |
311 | z->p->color = COLOR_BLACK; | |
312 | z->p->p->color = COLOR_RED; | |
313 | z = right_rotate(root, z->p->p, | |
314 | rballoc, rbfree); | |
315 | } | |
316 | } else { | |
317 | y = z->p->p->left; | |
318 | if (y->color == COLOR_RED) { | |
319 | z->p->color = COLOR_BLACK; | |
320 | y->color = COLOR_BLACK; | |
321 | z->p->p->color = COLOR_RED; | |
322 | z = z->p->p; | |
323 | } else { | |
324 | if (z == z->p->left) { | |
325 | z = z->p; | |
326 | z = right_rotate(root, z, | |
327 | rballoc, rbfree); | |
328 | } | |
329 | z->p->color = COLOR_BLACK; | |
330 | z->p->p->color = COLOR_RED; | |
331 | z = left_rotate(root, z->p->p, | |
332 | rballoc, rbfree); | |
333 | } | |
334 | } | |
335 | } | |
336 | (*root)->color = COLOR_BLACK; | |
337 | } | |
338 | ||
339 | /* | |
340 | * rcu_rbtree_insert - Insert a node in the RCU rbtree | |
341 | * | |
342 | * Returns 0 on success, or < 0 on error. | |
343 | */ | |
344 | int rcu_rbtree_insert(struct rcu_rbtree_node **root, | |
345 | struct rcu_rbtree_node *z, | |
346 | rcu_rbtree_comp comp, | |
347 | rcu_rbtree_alloc rballoc, | |
348 | rcu_rbtree_free rbfree) | |
349 | { | |
350 | struct rcu_rbtree_node *x, *y; | |
351 | ||
db5b1669 | 352 | y = &rcu_rbtree_nil; |
00131368 MD |
353 | x = *root; |
354 | ||
db5b1669 | 355 | while (x != &rcu_rbtree_nil) { |
00131368 MD |
356 | y = x; |
357 | if (comp(z->key, x->key) < 0) | |
358 | x = x->left; | |
359 | else | |
360 | x = x->right; | |
361 | } | |
362 | ||
363 | z->p = y; | |
db5b1669 MD |
364 | z->left = &rcu_rbtree_nil; |
365 | z->right = &rcu_rbtree_nil; | |
00131368 MD |
366 | z->color = COLOR_RED; |
367 | ||
368 | /* | |
369 | * Order stores to z (children/parents) before stores that will make it | |
370 | * visible to the rest of the tree. | |
371 | */ | |
372 | smp_wmb(); | |
373 | ||
db5b1669 | 374 | if (y == &rcu_rbtree_nil) |
00131368 MD |
375 | _STORE_SHARED(*root, z); |
376 | else if (comp(z->key, y->key) < 0) | |
377 | _STORE_SHARED(y->left, z); | |
378 | else | |
379 | _STORE_SHARED(y->right, z); | |
380 | rcu_rbtree_insert_fixup(root, z, rballoc, rbfree); | |
381 | /* | |
382 | * Make sure to commit all _STORE_SHARED() for non-coherent caches. | |
383 | */ | |
384 | smp_wmc(); | |
385 | ||
386 | return 0; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Transplant v into u position. | |
391 | * Returns new copy of v. | |
392 | */ | |
393 | static struct rcu_rbtree_node * | |
394 | rcu_rbtree_transplant(struct rcu_rbtree_node **root, | |
395 | struct rcu_rbtree_node *u, | |
396 | struct rcu_rbtree_node *v, | |
397 | rcu_rbtree_alloc rballoc, | |
398 | rcu_rbtree_free rbfree) | |
399 | { | |
400 | struct rcu_rbtree_node *vc; | |
401 | ||
402 | vc = rballoc(); | |
403 | *vc = *v; | |
404 | ||
405 | /* Change vc parent pointer */ | |
406 | vc->p = u->p; | |
407 | ||
408 | /* | |
409 | * Order stores to node copies (children/parents) before stores that | |
410 | * will make the copies visible to the rest of the tree. | |
411 | */ | |
412 | smp_wmb(); | |
413 | ||
414 | /* Assign upper-level pointer to vc, replacing u. */ | |
db5b1669 | 415 | if (u->p == &rcu_rbtree_nil) |
00131368 MD |
416 | _STORE_SHARED(*root, vc); |
417 | else if (u == u->p->left) | |
418 | _STORE_SHARED(u->p->left, vc); | |
419 | else | |
420 | _STORE_SHARED(u->p->right, vc); | |
421 | ||
422 | /* | |
423 | * The children pointers in vc are the same as v. We can therefore | |
424 | * reparent v's children to vc safely. | |
425 | */ | |
426 | _STORE_SHARED(vc->right->p, vc); | |
427 | _STORE_SHARED(vc->left->p, vc); | |
428 | ||
429 | defer_rcu(rbfree, v); | |
430 | return vc; | |
431 | } | |
432 | ||
433 | static void rcu_rbtree_remove_fixup(struct rcu_rbtree_node **root, | |
434 | struct rcu_rbtree_node *x, | |
435 | rcu_rbtree_alloc rballoc, | |
436 | rcu_rbtree_free rbfree) | |
437 | { | |
438 | while (x != *root && x->color == COLOR_BLACK) { | |
439 | if (x == x->p->left) { | |
440 | struct rcu_rbtree_node *w; | |
441 | ||
442 | w = x->p->right; | |
443 | if (w->color == COLOR_RED) { | |
444 | w->color == COLOR_BLACK; | |
445 | x->p->color = COLOR_RED; | |
446 | left_rotate(root, x->p, rballoc, rbfree); | |
447 | /* x is a left node, not copied by rotation */ | |
448 | w = x->p->right; | |
449 | } | |
450 | if (w->left->color == COLOR_BLACK | |
451 | && w->right->color == COLOR_BLACK) { | |
452 | w->color = COLOR_RED; | |
453 | x = x->p; | |
454 | } else { | |
455 | if (w->right->color == COLOR_BLACK) { | |
456 | w->left->color = COLOR_BLACK; | |
457 | w->color = COLOR_RED; | |
458 | right_rotate(root, w, rballoc, rbfree); | |
459 | w = x->p->right; | |
460 | } | |
461 | w->color = x->p->color; | |
462 | x->p->color = COLOR_BLACK; | |
463 | w->right->color = COLOR_BLACK; | |
464 | left_rotate(root, x->p, rballoc, rbfree); | |
465 | x = *root; | |
466 | } | |
467 | } else { | |
468 | struct rcu_rbtree_node *w; | |
469 | ||
470 | w = x->p->left; | |
471 | if (w->color == COLOR_RED) { | |
472 | w->color == COLOR_BLACK; | |
473 | x->p->color = COLOR_RED; | |
474 | right_rotate(root, x->p, rballoc, rbfree); | |
475 | /* x is a right node, not copied by rotation */ | |
476 | w = x->p->left; | |
477 | } | |
478 | if (w->right->color == COLOR_BLACK | |
479 | && w->left->color == COLOR_BLACK) { | |
480 | w->color = COLOR_RED; | |
481 | x = x->p; | |
482 | } else { | |
483 | if (w->left->color == COLOR_BLACK) { | |
484 | w->right->color = COLOR_BLACK; | |
485 | w->color = COLOR_RED; | |
486 | left_rotate(root, w, rballoc, rbfree); | |
487 | w = x->p->left; | |
488 | } | |
489 | w->color = x->p->color; | |
490 | x->p->color = COLOR_BLACK; | |
491 | w->left->color = COLOR_BLACK; | |
492 | right_rotate(root, x->p, rballoc, rbfree); | |
493 | x = *root; | |
494 | } | |
495 | } | |
496 | } | |
497 | x->color = COLOR_BLACK; | |
498 | } | |
499 | ||
500 | /* Returns the new copy of y->right */ | |
501 | static struct rcu_rbtree_node * | |
502 | rcu_rbtree_remove_nonil(struct rcu_rbtree_node **root, | |
503 | struct rcu_rbtree_node *z, | |
504 | struct rcu_rbtree_node *y, | |
505 | rcu_rbtree_comp comp, | |
506 | rcu_rbtree_alloc rballoc, | |
507 | rcu_rbtree_free rbfree) | |
508 | { | |
509 | struct rcu_rbtree_node *x, *xc, *yc; | |
510 | ||
511 | x = y->right; | |
512 | ||
513 | xc = rballoc(); | |
514 | yc = rballoc(); | |
515 | *xc = *x; | |
516 | *yc = *y; | |
517 | ||
518 | /* Update parent and children pointers within copies */ | |
519 | if (y->p == z) | |
520 | xc->p = yc; | |
521 | else { | |
522 | /* Transplant y->right (xc) into y, within copy */ | |
523 | xc->p = y->p; | |
524 | /* But also change the right pointer of yc */ | |
525 | yc->right = z->right; | |
526 | } | |
527 | /* Transplant y into z, within copy */ | |
528 | yc->p = z->p; | |
529 | ||
530 | yc->left = z->left; | |
531 | yc->color = z->color; | |
532 | ||
533 | /* | |
534 | * Order stores to node copies (children/parents) before stores that | |
535 | * will make the copies visible to the rest of the tree. | |
536 | */ | |
537 | smp_wmb(); | |
538 | ||
539 | /* Update external pointers */ | |
540 | ||
541 | if (y->p != z) { | |
542 | /* Transplant y->right into y, external parent links */ | |
543 | ||
544 | /* Assign upper-level pointer to xc, replacing y. */ | |
db5b1669 | 545 | if (y->p == &rcu_rbtree_nil) |
00131368 MD |
546 | _STORE_SHARED(*root, xc); |
547 | else if (y == y->p->left) | |
548 | _STORE_SHARED(y->p->left, xc); | |
549 | else | |
550 | _STORE_SHARED(y->p->right, xc); | |
551 | } | |
552 | ||
553 | /* Transplant y into z, update external parent links */ | |
db5b1669 | 554 | if (z->p == &rcu_rbtree_nil) |
00131368 MD |
555 | _STORE_SHARED(*root, yc); |
556 | else if (z == z->p->left) | |
557 | _STORE_SHARED(z->p->left, yc); | |
558 | else | |
559 | _STORE_SHARED(z->p->right, yc); | |
560 | ||
561 | /* Reparent xc's children to xc. */ | |
562 | _STORE_SHARED(xc->right->p, xc); | |
563 | _STORE_SHARED(xc->left->p, xc); | |
564 | /* Reparent yc's children to yc */ | |
565 | _STORE_SHARED(yc->right->p, yc); | |
566 | _STORE_SHARED(yc->left->p, yc); | |
567 | ||
568 | defer_rcu(rbfree, x); | |
569 | defer_rcu(rbfree, y); | |
570 | ||
571 | return xc; | |
572 | } | |
573 | ||
574 | int rcu_rbtree_remove(struct rcu_rbtree_node **root, | |
575 | struct rcu_rbtree_node *z, | |
576 | rcu_rbtree_comp comp, | |
577 | rcu_rbtree_alloc rballoc, | |
578 | rcu_rbtree_free rbfree) | |
579 | { | |
580 | struct rcu_rbtree_node *x, *y; | |
581 | unsigned int y_original_color; | |
582 | ||
583 | y = z; | |
584 | y_original_color = y->color; | |
585 | ||
db5b1669 | 586 | if (z->left == &rcu_rbtree_nil) { |
00131368 | 587 | x = rcu_rbtree_transplant(root, z, z->right, rballoc, rbfree); |
db5b1669 | 588 | } else if (z->right == &rcu_rbtree_nil) { |
00131368 MD |
589 | x = rcu_rbtree_transplant(root, z, z->left, rballoc, rbfree); |
590 | } else { | |
591 | y = rcu_rbtree_min(z->right, comp); | |
592 | y_original_color = y->color; | |
593 | x = rcu_rbtree_remove_nonil(root, z, y, comp, rballoc, rbfree); | |
594 | } | |
595 | if (y_original_color == COLOR_BLACK) | |
596 | rcu_rbtree_remove_fixup(root, x, rballoc, rbfree); | |
597 | /* | |
598 | * Commit all _STORE_SHARED(). | |
599 | */ | |
600 | smp_wmc(); | |
601 | ||
602 | return 0; | |
603 | } |