2 #include <linux/rbtree_augmented.h>
3 #include "drbd_interval.h"
6 * interval_end - return end of @node
9 sector_t interval_end(struct rb_node *node)
11 struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
16 * compute_subtree_last - compute end of @node
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
22 static inline sector_t
23 compute_subtree_last(struct drbd_interval *node)
25 sector_t max = node->sector + (node->size >> 9);
27 if (node->rb.rb_left) {
28 sector_t left = interval_end(node->rb.rb_left);
32 if (node->rb.rb_right) {
33 sector_t right = interval_end(node->rb.rb_right);
40 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct drbd_interval, rb,
41 sector_t, end, compute_subtree_last);
44 * drbd_insert_interval - insert a new interval into a tree
47 drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
49 struct rb_node **new = &root->rb_node, *parent = NULL;
50 sector_t this_end = this->sector + (this->size >> 9);
52 BUG_ON(!IS_ALIGNED(this->size, 512));
55 struct drbd_interval *here =
56 rb_entry(*new, struct drbd_interval, rb);
59 if (here->end < this_end)
61 if (this->sector < here->sector)
62 new = &(*new)->rb_left;
63 else if (this->sector > here->sector)
64 new = &(*new)->rb_right;
66 new = &(*new)->rb_left;
68 new = &(*new)->rb_right;
74 rb_link_node(&this->rb, parent, new);
75 rb_insert_augmented(&this->rb, root, &augment_callbacks);
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
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
90 drbd_contains_interval(struct rb_root *root, sector_t sector,
91 struct drbd_interval *interval)
93 struct rb_node *node = root->rb_node;
96 struct drbd_interval *here =
97 rb_entry(node, struct drbd_interval, rb);
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;
114 * drbd_remove_interval - remove an interval from a tree
117 drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
119 rb_erase_augmented(&this->rb, root, &augment_callbacks);
123 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
124 * @sector: start sector
125 * @size: size, aligned to 512 bytes
127 * 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
133 struct drbd_interval *
134 drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
136 struct rb_node *node = root->rb_node;
137 struct drbd_interval *overlap = NULL;
138 sector_t end = sector + (size >> 9);
140 BUG_ON(!IS_ALIGNED(size, 512));
143 struct drbd_interval *here =
144 rb_entry(node, struct drbd_interval, rb);
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)) {
154 } else if (sector >= here->sector) {
155 /* Overlap if any must be on right side */
156 node = node->rb_right;
163 struct drbd_interval *
164 drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
166 sector_t end = sector + (size >> 9);
167 struct rb_node *node;
170 node = rb_next(&i->rb);
173 i = rb_entry(node, struct drbd_interval, rb);
174 if (i->sector >= end)
176 if (sector < i->sector + (i->size >> 9))