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
|
/*
* Copyright (C) 2012 Red Hat. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm-cache-policy-internal.h"
#include "dm.h"
#include <linux/module.h>
#include <linux/slab.h>
/*----------------------------------------------------------------*/
#define DM_MSG_PREFIX "cache-policy"
static DEFINE_SPINLOCK(register_lock);
static LIST_HEAD(register_list);
static struct dm_cache_policy_type *__find_policy(const char *name)
{
struct dm_cache_policy_type *t;
list_for_each_entry(t, ®ister_list, list)
if (!strcmp(t->name, name))
return t;
return NULL;
}
static struct dm_cache_policy_type *__get_policy_once(const char *name)
{
struct dm_cache_policy_type *t = __find_policy(name);
if (t && !try_module_get(t->owner)) {
DMWARN("couldn't get module %s", name);
t = ERR_PTR(-EINVAL);
}
return t;
}
static struct dm_cache_policy_type *get_policy_once(const char *name)
{
struct dm_cache_policy_type *t;
spin_lock(®ister_lock);
t = __get_policy_once(name);
spin_unlock(®ister_lock);
return t;
}
static struct dm_cache_policy_type *get_policy(const char *name)
{
struct dm_cache_policy_type *t;
t = get_policy_once(name);
if (IS_ERR(t))
return NULL;
if (t)
return t;
request_module("dm-cache-%s", name);
t = get_policy_once(name);
if (IS_ERR(t))
return NULL;
return t;
}
static void put_policy(struct dm_cache_policy_type *t)
{
module_put(t->owner);
}
int dm_cache_policy_register(struct dm_cache_policy_type *type)
{
int r;
/* One size fits all for now */
if (type->hint_size != 0 && type->hint_size != 4) {
DMWARN("hint size must be 0 or 4 but %llu supplied.", (unsigned long long) type->hint_size);
return -EINVAL;
}
spin_lock(®ister_lock);
if (__find_policy(type->name)) {
DMWARN("attempt to register policy under duplicate name %s", type->name);
r = -EINVAL;
} else {
list_add(&type->list, ®ister_list);
r = 0;
}
spin_unlock(®ister_lock);
return r;
}
EXPORT_SYMBOL_GPL(dm_cache_policy_register);
void dm_cache_policy_unregister(struct dm_cache_policy_type *type)
{
spin_lock(®ister_lock);
list_del_init(&type->list);
spin_unlock(®ister_lock);
}
EXPORT_SYMBOL_GPL(dm_cache_policy_unregister);
struct dm_cache_policy *dm_cache_policy_create(const char *name,
dm_cblock_t cache_size,
sector_t origin_size,
sector_t cache_block_size)
{
struct dm_cache_policy *p = NULL;
struct dm_cache_policy_type *type;
type = get_policy(name);
if (!type) {
DMWARN("unknown policy type");
return NULL;
}
p = type->create(cache_size, origin_size, cache_block_size);
if (!p) {
put_policy(type);
return NULL;
}
p->private = type;
return p;
}
EXPORT_SYMBOL_GPL(dm_cache_policy_create);
void dm_cache_policy_destroy(struct dm_cache_policy *p)
{
struct dm_cache_policy_type *t = p->private;
p->destroy(p);
put_policy(t);
}
EXPORT_SYMBOL_GPL(dm_cache_policy_destroy);
const char *dm_cache_policy_get_name(struct dm_cache_policy *p)
{
struct dm_cache_policy_type *t = p->private;
return t->name;
}
EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);
const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p)
{
struct dm_cache_policy_type *t = p->private;
return t->version;
}
EXPORT_SYMBOL_GPL(dm_cache_policy_get_version);
size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p)
{
struct dm_cache_policy_type *t = p->private;
return t->hint_size;
}
EXPORT_SYMBOL_GPL(dm_cache_policy_get_hint_size);
/*----------------------------------------------------------------*/
|
