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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 | #include <asm/bug.h>
#include <linux/rbtree_augmented.h>
#include "drbd_interval.h"
/**
* interval_end - return end of @node
*/
static inline
sector_t interval_end(struct rb_node *node)
{
struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
return this->end;
}
/**
* compute_subtree_last - compute end of @node
*
* The end of an interval is the highest (start + (size >> 9)) value of this
* node and of its children. Called for @node and its parents whenever the end
* may have changed.
*/
static inline sector_t
compute_subtree_last(struct drbd_interval *node)
{
sector_t max = node->sector + (node->size >> 9);
if (node->rb.rb_left) {
sector_t left = interval_end(node->rb.rb_left);
if (left > max)
max = left;
}
if (node->rb.rb_right) {
sector_t right = interval_end(node->rb.rb_right);
if (right > max)
max = right;
}
return max;
}
RB_DECLARE_CALLBACKS(static, augment_callbacks, struct drbd_interval, rb,
sector_t, end, compute_subtree_last);
/**
* drbd_insert_interval - insert a new interval into a tree
*/
bool
drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
{
struct rb_node **new = &root->rb_node, *parent = NULL;
sector_t this_end = this->sector + (this->size >> 9);
BUG_ON(!IS_ALIGNED(this->size, 512));
while (*new) {
struct drbd_interval *here =
rb_entry(*new, struct drbd_interval, rb);
parent = *new;
if (here->end < this_end)
here->end = this_end;
if (this->sector < here->sector)
new = &(*new)->rb_left;
else if (this->sector > here->sector)
new = &(*new)->rb_right;
else if (this < here)
new = &(*new)->rb_left;
else if (this > here)
new = &(*new)->rb_right;
else
return false;
}
this->end = this_end;
rb_link_node(&this->rb, parent, new);
rb_insert_augmented(&this->rb, root, &augment_callbacks);
return true;
}
/**
* drbd_contains_interval - check if a tree contains a given interval
* @sector: start sector of @interval
* @interval: may not be a valid pointer
*
* Returns if the tree contains the node @interval with start sector @start.
* Does not dereference @interval until @interval is known to be a valid object
* in @tree. Returns %false if @interval is in the tree but with a different
* sector number.
*/
bool
drbd_contains_interval(struct rb_root *root, sector_t sector,
struct drbd_interval *interval)
{
struct rb_node *node = root->rb_node;
while (node) {
struct drbd_interval *here =
rb_entry(node, struct drbd_interval, rb);
if (sector < here->sector)
node = node->rb_left;
else if (sector > here->sector)
node = node->rb_right;
else if (interval < here)
node = node->rb_left;
else if (interval > here)
node = node->rb_right;
else
return true;
}
return false;
}
/**
* drbd_remove_interval - remove an interval from a tree
*/
void
drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
{
rb_erase_augmented(&this->rb, root, &augment_callbacks);
}
/**
* drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
* @sector: start sector
* @size: size, aligned to 512 bytes
*
* Returns an interval overlapping with [sector, sector + size), or NULL if
* there is none. When there is more than one overlapping interval in the
* tree, the interval with the lowest start sector is returned, and all other
* overlapping intervals will be on the right side of the tree, reachable with
* rb_next().
*/
struct drbd_interval *
drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
{
struct rb_node *node = root->rb_node;
struct drbd_interval *overlap = NULL;
sector_t end = sector + (size >> 9);
BUG_ON(!IS_ALIGNED(size, 512));
while (node) {
struct drbd_interval *here =
rb_entry(node, struct drbd_interval, rb);
if (node->rb_left &&
sector < interval_end(node->rb_left)) {
/* Overlap if any must be on left side */
node = node->rb_left;
} else if (here->sector < end &&
sector < here->sector + (here->size >> 9)) {
overlap = here;
break;
} else if (sector >= here->sector) {
/* Overlap if any must be on right side */
node = node->rb_right;
} else
break;
}
return overlap;
}
struct drbd_interval *
drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
{
sector_t end = sector + (size >> 9);
struct rb_node *node;
for (;;) {
node = rb_next(&i->rb);
if (!node)
return NULL;
i = rb_entry(node, struct drbd_interval, rb);
if (i->sector >= end)
return NULL;
if (sector < i->sector + (i->size >> 9))
return i;
}
}
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