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
|
// SPDX-License-Identifier: GPL-2.0-only
#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
* @root: red black tree root
* @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)
* @root: red black tree root
* @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;
}
}
|
