fio: fix aio trim completion latencies
[fio.git] / lib / rbtree.c
CommitLineData
4b87898e
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1/*
2 Red Black Trees
3 (C) 1999 Andrea Arcangeli <andrea@suse.de>
4 (C) 2002 David Woodhouse <dwmw2@infradead.org>
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
fa07eaa6 18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
4b87898e
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19
20 linux/lib/rbtree.c
21*/
22
23#include "rbtree.h"
24
e96c0125 25static void __rb_rotate_left(struct fio_rb_node *node, struct rb_root *root)
4b87898e 26{
e96c0125
BVA
27 struct fio_rb_node *right = node->rb_right;
28 struct fio_rb_node *parent = rb_parent(node);
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JA
29
30 if ((node->rb_right = right->rb_left))
44b5374f 31 rb_set_parent(right->rb_left, node);
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32 right->rb_left = node;
33
44b5374f
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34 rb_set_parent(right, parent);
35
36 if (parent)
4b87898e 37 {
44b5374f
JA
38 if (node == parent->rb_left)
39 parent->rb_left = right;
4b87898e 40 else
44b5374f 41 parent->rb_right = right;
4b87898e
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42 }
43 else
44 root->rb_node = right;
44b5374f 45 rb_set_parent(node, right);
4b87898e
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46}
47
e96c0125 48static void __rb_rotate_right(struct fio_rb_node *node, struct rb_root *root)
4b87898e 49{
e96c0125
BVA
50 struct fio_rb_node *left = node->rb_left;
51 struct fio_rb_node *parent = rb_parent(node);
4b87898e
JA
52
53 if ((node->rb_left = left->rb_right))
44b5374f 54 rb_set_parent(left->rb_right, node);
4b87898e
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55 left->rb_right = node;
56
44b5374f
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57 rb_set_parent(left, parent);
58
59 if (parent)
4b87898e 60 {
44b5374f
JA
61 if (node == parent->rb_right)
62 parent->rb_right = left;
4b87898e 63 else
44b5374f 64 parent->rb_left = left;
4b87898e
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65 }
66 else
67 root->rb_node = left;
44b5374f 68 rb_set_parent(node, left);
4b87898e
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69}
70
e96c0125 71void rb_insert_color(struct fio_rb_node *node, struct rb_root *root)
4b87898e 72{
e96c0125 73 struct fio_rb_node *parent, *gparent;
4b87898e 74
44b5374f 75 while ((parent = rb_parent(node)) && rb_is_red(parent))
4b87898e 76 {
44b5374f 77 gparent = rb_parent(parent);
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78
79 if (parent == gparent->rb_left)
80 {
81 {
e96c0125 82 register struct fio_rb_node *uncle = gparent->rb_right;
44b5374f 83 if (uncle && rb_is_red(uncle))
4b87898e 84 {
44b5374f
JA
85 rb_set_black(uncle);
86 rb_set_black(parent);
87 rb_set_red(gparent);
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88 node = gparent;
89 continue;
90 }
91 }
92
93 if (parent->rb_right == node)
94 {
e96c0125 95 register struct fio_rb_node *tmp;
4b87898e
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96 __rb_rotate_left(parent, root);
97 tmp = parent;
98 parent = node;
99 node = tmp;
100 }
101
44b5374f
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102 rb_set_black(parent);
103 rb_set_red(gparent);
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104 __rb_rotate_right(gparent, root);
105 } else {
106 {
e96c0125 107 register struct fio_rb_node *uncle = gparent->rb_left;
44b5374f 108 if (uncle && rb_is_red(uncle))
4b87898e 109 {
44b5374f
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110 rb_set_black(uncle);
111 rb_set_black(parent);
112 rb_set_red(gparent);
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113 node = gparent;
114 continue;
115 }
116 }
117
118 if (parent->rb_left == node)
119 {
e96c0125 120 register struct fio_rb_node *tmp;
4b87898e
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121 __rb_rotate_right(parent, root);
122 tmp = parent;
123 parent = node;
124 node = tmp;
125 }
126
44b5374f
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127 rb_set_black(parent);
128 rb_set_red(gparent);
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129 __rb_rotate_left(gparent, root);
130 }
131 }
132
44b5374f 133 rb_set_black(root->rb_node);
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134}
135
e96c0125
BVA
136static void __rb_erase_color(struct fio_rb_node *node,
137 struct fio_rb_node *parent,
4b87898e
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138 struct rb_root *root)
139{
e96c0125 140 struct fio_rb_node *other;
4b87898e 141
44b5374f 142 while ((!node || rb_is_black(node)) && node != root->rb_node)
4b87898e
JA
143 {
144 if (parent->rb_left == node)
145 {
146 other = parent->rb_right;
44b5374f 147 if (rb_is_red(other))
4b87898e 148 {
44b5374f
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149 rb_set_black(other);
150 rb_set_red(parent);
4b87898e
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151 __rb_rotate_left(parent, root);
152 other = parent->rb_right;
153 }
44b5374f
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154 if ((!other->rb_left || rb_is_black(other->rb_left)) &&
155 (!other->rb_right || rb_is_black(other->rb_right)))
4b87898e 156 {
44b5374f 157 rb_set_red(other);
4b87898e 158 node = parent;
44b5374f 159 parent = rb_parent(node);
4b87898e
JA
160 }
161 else
162 {
44b5374f 163 if (!other->rb_right || rb_is_black(other->rb_right))
4b87898e 164 {
e96c0125 165 struct fio_rb_node *o_left;
4b87898e 166 if ((o_left = other->rb_left))
44b5374f
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167 rb_set_black(o_left);
168 rb_set_red(other);
4b87898e
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169 __rb_rotate_right(other, root);
170 other = parent->rb_right;
171 }
44b5374f
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172 rb_set_color(other, rb_color(parent));
173 rb_set_black(parent);
4b87898e 174 if (other->rb_right)
44b5374f 175 rb_set_black(other->rb_right);
4b87898e
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176 __rb_rotate_left(parent, root);
177 node = root->rb_node;
178 break;
179 }
180 }
181 else
182 {
183 other = parent->rb_left;
44b5374f 184 if (rb_is_red(other))
4b87898e 185 {
44b5374f
JA
186 rb_set_black(other);
187 rb_set_red(parent);
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188 __rb_rotate_right(parent, root);
189 other = parent->rb_left;
190 }
44b5374f
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191 if ((!other->rb_left || rb_is_black(other->rb_left)) &&
192 (!other->rb_right || rb_is_black(other->rb_right)))
4b87898e 193 {
44b5374f 194 rb_set_red(other);
4b87898e 195 node = parent;
44b5374f 196 parent = rb_parent(node);
4b87898e
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197 }
198 else
199 {
44b5374f 200 if (!other->rb_left || rb_is_black(other->rb_left))
4b87898e 201 {
e96c0125 202 register struct fio_rb_node *o_right;
4b87898e 203 if ((o_right = other->rb_right))
44b5374f
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204 rb_set_black(o_right);
205 rb_set_red(other);
4b87898e
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206 __rb_rotate_left(other, root);
207 other = parent->rb_left;
208 }
44b5374f
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209 rb_set_color(other, rb_color(parent));
210 rb_set_black(parent);
4b87898e 211 if (other->rb_left)
44b5374f 212 rb_set_black(other->rb_left);
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213 __rb_rotate_right(parent, root);
214 node = root->rb_node;
215 break;
216 }
217 }
218 }
219 if (node)
44b5374f 220 rb_set_black(node);
4b87898e
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221}
222
e96c0125 223void rb_erase(struct fio_rb_node *node, struct rb_root *root)
4b87898e 224{
e96c0125 225 struct fio_rb_node *child, *parent;
4b87898e
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226 int color;
227
228 if (!node->rb_left)
229 child = node->rb_right;
230 else if (!node->rb_right)
231 child = node->rb_left;
232 else
233 {
e96c0125 234 struct fio_rb_node *old = node, *left;
4b87898e
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235
236 node = node->rb_right;
237 while ((left = node->rb_left) != NULL)
238 node = left;
239 child = node->rb_right;
44b5374f
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240 parent = rb_parent(node);
241 color = rb_color(node);
4b87898e
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242
243 if (child)
44b5374f
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244 rb_set_parent(child, parent);
245 if (parent == old) {
246 parent->rb_right = child;
4b87898e 247 parent = node;
44b5374f
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248 } else
249 parent->rb_left = child;
250
251 node->rb_parent_color = old->rb_parent_color;
4b87898e
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252 node->rb_right = old->rb_right;
253 node->rb_left = old->rb_left;
254
44b5374f 255 if (rb_parent(old))
4b87898e 256 {
44b5374f
JA
257 if (rb_parent(old)->rb_left == old)
258 rb_parent(old)->rb_left = node;
4b87898e 259 else
44b5374f 260 rb_parent(old)->rb_right = node;
4b87898e
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261 } else
262 root->rb_node = node;
263
44b5374f 264 rb_set_parent(old->rb_left, node);
4b87898e 265 if (old->rb_right)
44b5374f 266 rb_set_parent(old->rb_right, node);
4b87898e
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267 goto color;
268 }
269
44b5374f
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270 parent = rb_parent(node);
271 color = rb_color(node);
4b87898e
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272
273 if (child)
44b5374f 274 rb_set_parent(child, parent);
4b87898e
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275 if (parent)
276 {
277 if (parent->rb_left == node)
278 parent->rb_left = child;
279 else
280 parent->rb_right = child;
281 }
282 else
283 root->rb_node = child;
284
285 color:
286 if (color == RB_BLACK)
287 __rb_erase_color(child, parent, root);
288}
289
290/*
291 * This function returns the first node (in sort order) of the tree.
292 */
e96c0125 293struct fio_rb_node *rb_first(struct rb_root *root)
4b87898e 294{
e96c0125 295 struct fio_rb_node *n;
4b87898e
JA
296
297 n = root->rb_node;
298 if (!n)
299 return NULL;
300 while (n->rb_left)
301 n = n->rb_left;
302 return n;
303}
8f2b1374 304
e96c0125 305struct fio_rb_node *rb_next(const struct fio_rb_node *node)
8f2b1374 306{
e96c0125 307 struct fio_rb_node *parent;
8f2b1374
JA
308
309 if (RB_EMPTY_NODE(node))
310 return NULL;
311
312 /*
313 * If we have a right-hand child, go down and then left as far
314 * as we can.
315 */
316 if (node->rb_right) {
317 node = node->rb_right;
318 while (node->rb_left)
319 node=node->rb_left;
e96c0125 320 return (struct fio_rb_node *)node;
8f2b1374
JA
321 }
322
323 /*
324 * No right-hand children. Everything down and left is smaller than us,
325 * so any 'next' node must be in the general direction of our parent.
326 * Go up the tree; any time the ancestor is a right-hand child of its
327 * parent, keep going up. First time it's a left-hand child of its
328 * parent, said parent is our 'next' node.
329 */
330 while ((parent = rb_parent(node)) && node == parent->rb_right)
331 node = parent;
332
333 return parent;
334}