source: GPL/trunk/include/linux/rbtree_augmented.h

Last change on this file was 679, checked in by David Azarewicz, 4 years ago

Merge changes from Paul's uniaud32next branch.
File size: 9.5 KB
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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 Red Black Trees
4 (C) 1999 Andrea Arcangeli <andrea@suse.de>
5 (C) 2002 David Woodhouse <dwmw2@infradead.org>
6 (C) 2012 Michel Lespinasse <walken@google.com>
7
8
9 linux/include/linux/rbtree_augmented.h
10*/
11
12/* from 5.10.10 */
13
14#ifndef _LINUX_RBTREE_AUGMENTED_H
15#define _LINUX_RBTREE_AUGMENTED_H
16
17#include <linux/compiler.h>
18#include <linux/rbtree.h>
19//#include <linux/rcupdate.h>
20
21/*
22 * Please note - only struct rb_augment_callbacks and the prototypes for
23 * rb_insert_augmented() and rb_erase_augmented() are intended to be public.
24 * The rest are implementation details you are not expected to depend on.
25 *
26 * See Documentation/core-api/rbtree.rst for documentation and samples.
27 */
28
29struct rb_augment_callbacks {
30 void (*propagate)(struct rb_node *node, struct rb_node *stop);
31 void (*copy)(struct rb_node *old, struct rb_node *new);
32 void (*rotate)(struct rb_node *old, struct rb_node *new);
33};
34
35extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
36 void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
37
38/*
39 * Fixup the rbtree and update the augmented information when rebalancing.
40 *
41 * On insertion, the user must update the augmented information on the path
42 * leading to the inserted node, then call rb_link_node() as usual and
43 * rb_insert_augmented() instead of the usual rb_insert_color() call.
44 * If rb_insert_augmented() rebalances the rbtree, it will callback into
45 * a user provided function to update the augmented information on the
46 * affected subtrees.
47 */
48static inline void
49rb_insert_augmented(struct rb_node *node, struct rb_root *root,
50 const struct rb_augment_callbacks *augment)
51{
52 __rb_insert_augmented(node, root, augment->rotate);
53}
54
55static inline void
56rb_insert_augmented_cached(struct rb_node *node,
57 struct rb_root_cached *root, bool newleft,
58 const struct rb_augment_callbacks *augment)
59{
60 if (newleft)
61 root->rb_leftmost = node;
62 rb_insert_augmented(node, &root->rb_root, augment);
63}
64
65/*
66 * Template for declaring augmented rbtree callbacks (generic case)
67 *
68 * RBSTATIC: 'static' or empty
69 * RBNAME: name of the rb_augment_callbacks structure
70 * RBSTRUCT: struct type of the tree nodes
71 * RBFIELD: name of struct rb_node field within RBSTRUCT
72 * RBAUGMENTED: name of field within RBSTRUCT holding data for subtree
73 * RBCOMPUTE: name of function that recomputes the RBAUGMENTED data
74 */
75
76#define RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \
77 RBSTRUCT, RBFIELD, RBAUGMENTED, RBCOMPUTE) \
78static inline void \
79RBNAME ## _propagate(struct rb_node *rb, struct rb_node *stop) \
80{ \
81 while (rb != stop) { \
82 RBSTRUCT *node = rb_entry(rb, RBSTRUCT, RBFIELD); \
83 if (RBCOMPUTE(node, true)) \
84 break; \
85 rb = rb_parent(&node->RBFIELD); \
86 } \
87} \
88static inline void \
89RBNAME ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
90{ \
91 RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
92 RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
93 new->RBAUGMENTED = old->RBAUGMENTED; \
94} \
95static void \
96RBNAME ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
97{ \
98 RBSTRUCT *old = rb_entry(rb_old, RBSTRUCT, RBFIELD); \
99 RBSTRUCT *new = rb_entry(rb_new, RBSTRUCT, RBFIELD); \
100 new->RBAUGMENTED = old->RBAUGMENTED; \
101 RBCOMPUTE(old, false); \
102} \
103RBSTATIC const struct rb_augment_callbacks RBNAME = { \
104 .propagate = RBNAME ## _propagate, \
105 .copy = RBNAME ## _copy, \
106 .rotate = RBNAME ## _rotate \
107};
108
109/*
110 * Template for declaring augmented rbtree callbacks,
111 * computing RBAUGMENTED scalar as max(RBCOMPUTE(node)) for all subtree nodes.
112 *
113 * RBSTATIC: 'static' or empty
114 * RBNAME: name of the rb_augment_callbacks structure
115 * RBSTRUCT: struct type of the tree nodes
116 * RBFIELD: name of struct rb_node field within RBSTRUCT
117 * RBTYPE: type of the RBAUGMENTED field
118 * RBAUGMENTED: name of RBTYPE field within RBSTRUCT holding data for subtree
119 * RBCOMPUTE: name of function that returns the per-node RBTYPE scalar
120 */
121
122#define RB_DECLARE_CALLBACKS_MAX(RBSTATIC, RBNAME, RBSTRUCT, RBFIELD, \
123 RBTYPE, RBAUGMENTED, RBCOMPUTE) \
124static inline bool RBNAME ## _compute_max(RBSTRUCT *node, bool exit) \
125{ \
126 RBSTRUCT *child; \
127 RBTYPE max = RBCOMPUTE(node); \
128 if (node->RBFIELD.rb_left) { \
129 child = rb_entry(node->RBFIELD.rb_left, RBSTRUCT, RBFIELD); \
130 if (child->RBAUGMENTED > max) \
131 max = child->RBAUGMENTED; \
132 } \
133 if (node->RBFIELD.rb_right) { \
134 child = rb_entry(node->RBFIELD.rb_right, RBSTRUCT, RBFIELD); \
135 if (child->RBAUGMENTED > max) \
136 max = child->RBAUGMENTED; \
137 } \
138 if (exit && node->RBAUGMENTED == max) \
139 return true; \
140 node->RBAUGMENTED = max; \
141 return false; \
142} \
143RB_DECLARE_CALLBACKS(RBSTATIC, RBNAME, \
144 RBSTRUCT, RBFIELD, RBAUGMENTED, RBNAME ## _compute_max)
145
146
147#define RB_RED 0
148#define RB_BLACK 1
149
150#define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
151
152#define __rb_color(pc) ((pc) & 1)
153#define __rb_is_black(pc) __rb_color(pc)
154#define __rb_is_red(pc) (!__rb_color(pc))
155#define rb_color(rb) __rb_color((rb)->__rb_parent_color)
156#define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
157#define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
158
159static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
160{
161 rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
162}
163
164static inline void rb_set_parent_color(struct rb_node *rb,
165 struct rb_node *p, int color)
166{
167 rb->__rb_parent_color = (unsigned long)p | color;
168}
169
170static inline void
171__rb_change_child(struct rb_node *old, struct rb_node *new,
172 struct rb_node *parent, struct rb_root *root)
173{
174 if (parent) {
175 if (parent->rb_left == old)
176 WRITE_ONCE(parent->rb_left, new);
177 else
178 WRITE_ONCE(parent->rb_right, new);
179 } else
180 WRITE_ONCE(root->rb_node, new);
181}
182
183#ifndef TARGET_OS2
184static inline void
185__rb_change_child_rcu(struct rb_node *old, struct rb_node *new,
186 struct rb_node *parent, struct rb_root *root)
187{
188 if (parent) {
189 if (parent->rb_left == old)
190 rcu_assign_pointer(parent->rb_left, new);
191 else
192 rcu_assign_pointer(parent->rb_right, new);
193 } else
194 rcu_assign_pointer(root->rb_node, new);
195}
196#endif
197
198extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
199 void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
200
201static inline struct rb_node *
202__rb_erase_augmented(struct rb_node *node, struct rb_root *root,
203 const struct rb_augment_callbacks *augment)
204{
205 struct rb_node *child = node->rb_right;
206 struct rb_node *tmp = node->rb_left;
207 struct rb_node *parent, *rebalance;
208 unsigned long pc;
209
210 if (!tmp) {
211 /*
212 * Case 1: node to erase has no more than 1 child (easy!)
213 *
214 * Note that if there is one child it must be red due to 5)
215 * and node must be black due to 4). We adjust colors locally
216 * so as to bypass __rb_erase_color() later on.
217 */
218 pc = node->__rb_parent_color;
219 parent = __rb_parent(pc);
220 __rb_change_child(node, child, parent, root);
221 if (child) {
222 child->__rb_parent_color = pc;
223 rebalance = NULL;
224 } else
225 rebalance = __rb_is_black(pc) ? parent : NULL;
226 tmp = parent;
227 } else if (!child) {
228 /* Still case 1, but this time the child is node->rb_left */
229 tmp->__rb_parent_color = pc = node->__rb_parent_color;
230 parent = __rb_parent(pc);
231 __rb_change_child(node, tmp, parent, root);
232 rebalance = NULL;
233 tmp = parent;
234 } else {
235 struct rb_node *successor = child, *child2;
236
237 tmp = child->rb_left;
238 if (!tmp) {
239 /*
240 * Case 2: node's successor is its right child
241 *
242 * (n) (s)
243 * / \ / \
244 * (x) (s) -> (x) (c)
245 * \
246 * (c)
247 */
248 parent = successor;
249 child2 = successor->rb_right;
250
251 augment->copy(node, successor);
252 } else {
253 /*
254 * Case 3: node's successor is leftmost under
255 * node's right child subtree
256 *
257 * (n) (s)
258 * / \ / \
259 * (x) (y) -> (x) (y)
260 * / /
261 * (p) (p)
262 * / /
263 * (s) (c)
264 * \
265 * (c)
266 */
267 do {
268 parent = successor;
269 successor = tmp;
270 tmp = tmp->rb_left;
271 } while (tmp);
272 child2 = successor->rb_right;
273 WRITE_ONCE(parent->rb_left, child2);
274 WRITE_ONCE(successor->rb_right, child);
275 rb_set_parent(child, successor);
276
277 augment->copy(node, successor);
278 augment->propagate(parent, successor);
279 }
280
281 tmp = node->rb_left;
282 WRITE_ONCE(successor->rb_left, tmp);
283 rb_set_parent(tmp, successor);
284
285 pc = node->__rb_parent_color;
286 tmp = __rb_parent(pc);
287 __rb_change_child(node, successor, tmp, root);
288
289 if (child2) {
290 rb_set_parent_color(child2, parent, RB_BLACK);
291 rebalance = NULL;
292 } else {
293 rebalance = rb_is_black(successor) ? parent : NULL;
294 }
295 successor->__rb_parent_color = pc;
296 tmp = successor;
297 }
298
299 augment->propagate(tmp, NULL);
300 return rebalance;
301}
302
303static inline void
304rb_erase_augmented(struct rb_node *node, struct rb_root *root,
305 const struct rb_augment_callbacks *augment)
306{
307 struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
308 if (rebalance)
309 __rb_erase_color(rebalance, root, augment->rotate);
310}
311
312static inline void
313rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root,
314 const struct rb_augment_callbacks *augment)
315{
316 if (root->rb_leftmost == node)
317 root->rb_leftmost = rb_next(node);
318 rb_erase_augmented(node, &root->rb_root, augment);
319}
320
321#endif /* _LINUX_RBTREE_AUGMENTED_H */
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