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);
16 #define NODE_END(node) ((node)->sector + ((node)->size >> 9))
18 RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
19 struct drbd_interval, rb, sector_t, end, NODE_END);
22 * drbd_insert_interval - insert a new interval into a tree
25 drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
27 struct rb_node **new = &root->rb_node, *parent = NULL;
28 sector_t this_end = this->sector + (this->size >> 9);
30 BUG_ON(!IS_ALIGNED(this->size, 512));
33 struct drbd_interval *here =
34 rb_entry(*new, struct drbd_interval, rb);
37 if (here->end < this_end)
39 if (this->sector < here->sector)
40 new = &(*new)->rb_left;
41 else if (this->sector > here->sector)
42 new = &(*new)->rb_right;
44 new = &(*new)->rb_left;
46 new = &(*new)->rb_right;
52 rb_link_node(&this->rb, parent, new);
53 rb_insert_augmented(&this->rb, root, &augment_callbacks);
58 * drbd_contains_interval - check if a tree contains a given interval
59 * @root: red black tree root
60 * @sector: start sector of @interval
61 * @interval: may not be a valid pointer
63 * Returns if the tree contains the node @interval with start sector @start.
64 * Does not dereference @interval until @interval is known to be a valid object
65 * in @tree. Returns %false if @interval is in the tree but with a different
69 drbd_contains_interval(struct rb_root *root, sector_t sector,
70 struct drbd_interval *interval)
72 struct rb_node *node = root->rb_node;
75 struct drbd_interval *here =
76 rb_entry(node, struct drbd_interval, rb);
78 if (sector < here->sector)
80 else if (sector > here->sector)
81 node = node->rb_right;
82 else if (interval < here)
84 else if (interval > here)
85 node = node->rb_right;
93 * drbd_remove_interval - remove an interval from a tree
96 drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
98 rb_erase_augmented(&this->rb, root, &augment_callbacks);
102 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
103 * @root: red black tree root
104 * @sector: start sector
105 * @size: size, aligned to 512 bytes
107 * Returns an interval overlapping with [sector, sector + size), or NULL if
108 * there is none. When there is more than one overlapping interval in the
109 * tree, the interval with the lowest start sector is returned, and all other
110 * overlapping intervals will be on the right side of the tree, reachable with
113 struct drbd_interval *
114 drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
116 struct rb_node *node = root->rb_node;
117 struct drbd_interval *overlap = NULL;
118 sector_t end = sector + (size >> 9);
120 BUG_ON(!IS_ALIGNED(size, 512));
123 struct drbd_interval *here =
124 rb_entry(node, struct drbd_interval, rb);
127 sector < interval_end(node->rb_left)) {
128 /* Overlap if any must be on left side */
129 node = node->rb_left;
130 } else if (here->sector < end &&
131 sector < here->sector + (here->size >> 9)) {
134 } else if (sector >= here->sector) {
135 /* Overlap if any must be on right side */
136 node = node->rb_right;
143 struct drbd_interval *
144 drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
146 sector_t end = sector + (size >> 9);
147 struct rb_node *node;
150 node = rb_next(&i->rb);
153 i = rb_entry(node, struct drbd_interval, rb);
154 if (i->sector >= end)
156 if (sector < i->sector + (i->size >> 9))