1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/rbtree_augmented.h>
4 #include "drbd_interval.h"
7 * interval_end - return end of @node
10 sector_t interval_end(struct rb_node *node)
12 struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
17 * compute_subtree_last - compute end of @node
19 * The end of an interval is the highest (start + (size >> 9)) value of this
20 * node and of its children. Called for @node and its parents whenever the end
23 static inline sector_t
24 compute_subtree_last(struct drbd_interval *node)
26 sector_t max = node->sector + (node->size >> 9);
28 if (node->rb.rb_left) {
29 sector_t left = interval_end(node->rb.rb_left);
33 if (node->rb.rb_right) {
34 sector_t right = interval_end(node->rb.rb_right);
41 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct drbd_interval, rb,
42 sector_t, end, compute_subtree_last);
45 * drbd_insert_interval - insert a new interval into a tree
48 drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
50 struct rb_node **new = &root->rb_node, *parent = NULL;
51 sector_t this_end = this->sector + (this->size >> 9);
53 BUG_ON(!IS_ALIGNED(this->size, 512));
56 struct drbd_interval *here =
57 rb_entry(*new, struct drbd_interval, rb);
60 if (here->end < this_end)
62 if (this->sector < here->sector)
63 new = &(*new)->rb_left;
64 else if (this->sector > here->sector)
65 new = &(*new)->rb_right;
67 new = &(*new)->rb_left;
69 new = &(*new)->rb_right;
75 rb_link_node(&this->rb, parent, new);
76 rb_insert_augmented(&this->rb, root, &augment_callbacks);
81 * drbd_contains_interval - check if a tree contains a given interval
82 * @sector: start sector of @interval
83 * @interval: may not be a valid pointer
85 * Returns if the tree contains the node @interval with start sector @start.
86 * Does not dereference @interval until @interval is known to be a valid object
87 * in @tree. Returns %false if @interval is in the tree but with a different
91 drbd_contains_interval(struct rb_root *root, sector_t sector,
92 struct drbd_interval *interval)
94 struct rb_node *node = root->rb_node;
97 struct drbd_interval *here =
98 rb_entry(node, struct drbd_interval, rb);
100 if (sector < here->sector)
101 node = node->rb_left;
102 else if (sector > here->sector)
103 node = node->rb_right;
104 else if (interval < here)
105 node = node->rb_left;
106 else if (interval > here)
107 node = node->rb_right;
115 * drbd_remove_interval - remove an interval from a tree
118 drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
120 rb_erase_augmented(&this->rb, root, &augment_callbacks);
124 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
125 * @sector: start sector
126 * @size: size, aligned to 512 bytes
128 * Returns an interval overlapping with [sector, sector + size), or NULL if
129 * there is none. When there is more than one overlapping interval in the
130 * tree, the interval with the lowest start sector is returned, and all other
131 * overlapping intervals will be on the right side of the tree, reachable with
134 struct drbd_interval *
135 drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
137 struct rb_node *node = root->rb_node;
138 struct drbd_interval *overlap = NULL;
139 sector_t end = sector + (size >> 9);
141 BUG_ON(!IS_ALIGNED(size, 512));
144 struct drbd_interval *here =
145 rb_entry(node, struct drbd_interval, rb);
148 sector < interval_end(node->rb_left)) {
149 /* Overlap if any must be on left side */
150 node = node->rb_left;
151 } else if (here->sector < end &&
152 sector < here->sector + (here->size >> 9)) {
155 } else if (sector >= here->sector) {
156 /* Overlap if any must be on right side */
157 node = node->rb_right;
164 struct drbd_interval *
165 drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
167 sector_t end = sector + (size >> 9);
168 struct rb_node *node;
171 node = rb_next(&i->rb);
174 i = rb_entry(node, struct drbd_interval, rb);
175 if (i->sector >= end)
177 if (sector < i->sector + (i->size >> 9))