158 lines
4.0 KiB
C
158 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#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;
|
|
}
|
|
|
|
#define NODE_END(node) ((node)->sector + ((node)->size >> 9))
|
|
|
|
RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
|
|
struct drbd_interval, rb, sector_t, end, NODE_END);
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
}
|