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Philipp Reisner98683652012-11-09 14:18:43 +01001#include <asm/bug.h>
2#include <linux/rbtree_augmented.h>
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +01003#include "drbd_interval.h"
4
5/**
6 * interval_end - return end of @node
7 */
8static inline
9sector_t interval_end(struct rb_node *node)
10{
11 struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
12 return this->end;
13}
14
15/**
Philipp Reisner98683652012-11-09 14:18:43 +010016 * compute_subtree_last - compute end of @node
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010017 *
18 * The end of an interval is the highest (start + (size >> 9)) value of this
19 * node and of its children. Called for @node and its parents whenever the end
20 * may have changed.
21 */
Philipp Reisner98683652012-11-09 14:18:43 +010022static inline sector_t
23compute_subtree_last(struct drbd_interval *node)
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010024{
Philipp Reisner98683652012-11-09 14:18:43 +010025 sector_t max = node->sector + (node->size >> 9);
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010026
Philipp Reisner98683652012-11-09 14:18:43 +010027 if (node->rb.rb_left) {
28 sector_t left = interval_end(node->rb.rb_left);
29 if (left > max)
30 max = left;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010031 }
Philipp Reisner98683652012-11-09 14:18:43 +010032 if (node->rb.rb_right) {
33 sector_t right = interval_end(node->rb.rb_right);
34 if (right > max)
35 max = right;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010036 }
Philipp Reisner98683652012-11-09 14:18:43 +010037 return max;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010038}
39
Lai Jiangshane9f05b42014-09-18 16:49:42 +020040RB_DECLARE_CALLBACKS(static, augment_callbacks, struct drbd_interval, rb,
41 sector_t, end, compute_subtree_last);
Philipp Reisner98683652012-11-09 14:18:43 +010042
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010043/**
44 * drbd_insert_interval - insert a new interval into a tree
45 */
46bool
47drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
48{
49 struct rb_node **new = &root->rb_node, *parent = NULL;
Lai Jiangshan82cfb902014-09-18 16:49:41 +020050 sector_t this_end = this->sector + (this->size >> 9);
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010051
52 BUG_ON(!IS_ALIGNED(this->size, 512));
53
54 while (*new) {
55 struct drbd_interval *here =
56 rb_entry(*new, struct drbd_interval, rb);
57
58 parent = *new;
Lai Jiangshan82cfb902014-09-18 16:49:41 +020059 if (here->end < this_end)
60 here->end = this_end;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010061 if (this->sector < here->sector)
62 new = &(*new)->rb_left;
63 else if (this->sector > here->sector)
64 new = &(*new)->rb_right;
65 else if (this < here)
66 new = &(*new)->rb_left;
Andreas Gruenbacher6618bf12011-01-26 13:06:08 +010067 else if (this > here)
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010068 new = &(*new)->rb_right;
Andreas Gruenbacher6618bf12011-01-26 13:06:08 +010069 else
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010070 return false;
71 }
72
Lai Jiangshan82cfb902014-09-18 16:49:41 +020073 this->end = this_end;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010074 rb_link_node(&this->rb, parent, new);
Philipp Reisner98683652012-11-09 14:18:43 +010075 rb_insert_augmented(&this->rb, root, &augment_callbacks);
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +010076 return true;
77}
78
79/**
80 * drbd_contains_interval - check if a tree contains a given interval
81 * @sector: start sector of @interval
82 * @interval: may not be a valid pointer
83 *
84 * Returns if the tree contains the node @interval with start sector @start.
85 * Does not dereference @interval until @interval is known to be a valid object
86 * in @tree. Returns %false if @interval is in the tree but with a different
87 * sector number.
88 */
89bool
90drbd_contains_interval(struct rb_root *root, sector_t sector,
91 struct drbd_interval *interval)
92{
93 struct rb_node *node = root->rb_node;
94
95 while (node) {
96 struct drbd_interval *here =
97 rb_entry(node, struct drbd_interval, rb);
98
99 if (sector < here->sector)
100 node = node->rb_left;
101 else if (sector > here->sector)
102 node = node->rb_right;
103 else if (interval < here)
104 node = node->rb_left;
105 else if (interval > here)
106 node = node->rb_right;
107 else
Andreas Gruenbacher3e051462011-01-27 16:20:57 +0100108 return true;
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +0100109 }
110 return false;
111}
112
113/**
114 * drbd_remove_interval - remove an interval from a tree
115 */
116void
117drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
118{
Philipp Reisner98683652012-11-09 14:18:43 +0100119 rb_erase_augmented(&this->rb, root, &augment_callbacks);
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +0100120}
121
122/**
123 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
124 * @sector: start sector
125 * @size: size, aligned to 512 bytes
126 *
Andreas Gruenbacher70b19872011-02-04 12:11:05 +0100127 * Returns an interval overlapping with [sector, sector + size), or NULL if
128 * there is none. When there is more than one overlapping interval in the
129 * tree, the interval with the lowest start sector is returned, and all other
130 * overlapping intervals will be on the right side of the tree, reachable with
131 * rb_next().
Andreas Gruenbacher0939b0e2011-01-03 17:42:00 +0100132 */
133struct drbd_interval *
134drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
135{
136 struct rb_node *node = root->rb_node;
137 struct drbd_interval *overlap = NULL;
138 sector_t end = sector + (size >> 9);
139
140 BUG_ON(!IS_ALIGNED(size, 512));
141
142 while (node) {
143 struct drbd_interval *here =
144 rb_entry(node, struct drbd_interval, rb);
145
146 if (node->rb_left &&
147 sector < interval_end(node->rb_left)) {
148 /* Overlap if any must be on left side */
149 node = node->rb_left;
150 } else if (here->sector < end &&
151 sector < here->sector + (here->size >> 9)) {
152 overlap = here;
153 break;
154 } else if (sector >= here->sector) {
155 /* Overlap if any must be on right side */
156 node = node->rb_right;
157 } else
158 break;
159 }
160 return overlap;
161}
Andreas Gruenbacherd0e22a22011-02-17 18:11:24 +0100162
163struct drbd_interval *
164drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
165{
166 sector_t end = sector + (size >> 9);
167 struct rb_node *node;
168
169 for (;;) {
170 node = rb_next(&i->rb);
171 if (!node)
172 return NULL;
173 i = rb_entry(node, struct drbd_interval, rb);
174 if (i->sector >= end)
175 return NULL;
176 if (sector < i->sector + (i->size >> 9))
177 return i;
178 }
179}