1 /*
2 * Copyright (c) 2019 Matthew Dillon <dillon@backplane.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <linux/init.h>
28 #include <linux/interval_tree.h>
29 #include <linux/module.h>
30
31 typedef struct interval_tree_node itnode_t;
32
33 void
interval_tree_insert(struct interval_tree_node * node,struct rb_root * root)34 interval_tree_insert(struct interval_tree_node *node, struct rb_root *root)
35 {
36 itnode_t *scan;
37
38 scan = (itnode_t *)root->rb_node;
39 if (scan) {
40 node->next = scan->next;
41 node->atroot = 0;
42 scan->next = node;
43 } else {
44 root->rb_node = (void *)node;
45 node->atroot = 1;
46 node->next = node;
47 }
48 }
49
50 void
interval_tree_remove(struct interval_tree_node * node,struct rb_root * root)51 interval_tree_remove(struct interval_tree_node *node, struct rb_root *root)
52 {
53 itnode_t *scan;
54
55 scan = (itnode_t *)root->rb_node;
56 KKASSERT(scan != NULL);
57 while (scan->next != node) {
58 scan = scan->next;
59 }
60 scan->next = node->next;
61 if (scan == node) {
62 /*
63 * Last element is being removed
64 */
65 root->rb_node = NULL;
66 node->atroot = 0;
67 } else if ((itnode_t *)root->rb_node == node) {
68 /*
69 * Root pointer is the node being removed, move the root
70 * pointer.
71 */
72 node->atroot = 0;
73 scan->atroot = 1;
74 root->rb_node = (void *)scan;
75 }
76 }
77
78 struct interval_tree_node *
interval_tree_iter_first(struct rb_root * root,unsigned long start,unsigned long last)79 interval_tree_iter_first(struct rb_root *root,
80 unsigned long start, unsigned long last)
81 {
82 itnode_t *scan;
83
84 scan = (itnode_t *)root->rb_node;
85 if (scan) {
86 do {
87 if (start <= scan->last &&
88 last >= scan->start) {
89 return scan;
90 }
91 scan = scan->next;
92 } while (scan->atroot == 0);
93 scan = NULL;
94 }
95 return scan;
96 }
97
98 struct interval_tree_node *
interval_tree_iter_next(struct interval_tree_node * node,unsigned long start,unsigned long last)99 interval_tree_iter_next(struct interval_tree_node *node,
100 unsigned long start, unsigned long last)
101 {
102 itnode_t *scan;
103
104 scan = node->next;
105 while (scan->atroot == 0) {
106 if (start <= scan->last &&
107 last >= scan->start) {
108 return scan;
109 }
110 scan = scan->next;
111 }
112 return NULL;
113 }
114