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3bd94003 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
c6b4fcba JT |
2 | /* |
3 | * Copyright (C) 2012 Red Hat. All rights reserved. | |
4 | * | |
5 | * This file is released under the GPL. | |
6 | */ | |
7 | ||
8 | #include "dm-cache-policy-internal.h" | |
9 | #include "dm.h" | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/slab.h> | |
13 | ||
14 | /*----------------------------------------------------------------*/ | |
15 | ||
16 | #define DM_MSG_PREFIX "cache-policy" | |
17 | ||
18 | static DEFINE_SPINLOCK(register_lock); | |
19 | static LIST_HEAD(register_list); | |
20 | ||
21 | static struct dm_cache_policy_type *__find_policy(const char *name) | |
22 | { | |
23 | struct dm_cache_policy_type *t; | |
24 | ||
25 | list_for_each_entry(t, ®ister_list, list) | |
26 | if (!strcmp(t->name, name)) | |
27 | return t; | |
28 | ||
29 | return NULL; | |
30 | } | |
31 | ||
32 | static struct dm_cache_policy_type *__get_policy_once(const char *name) | |
33 | { | |
34 | struct dm_cache_policy_type *t = __find_policy(name); | |
35 | ||
36 | if (t && !try_module_get(t->owner)) { | |
37 | DMWARN("couldn't get module %s", name); | |
38 | t = ERR_PTR(-EINVAL); | |
39 | } | |
40 | ||
41 | return t; | |
42 | } | |
43 | ||
44 | static struct dm_cache_policy_type *get_policy_once(const char *name) | |
45 | { | |
46 | struct dm_cache_policy_type *t; | |
47 | ||
48 | spin_lock(®ister_lock); | |
49 | t = __get_policy_once(name); | |
50 | spin_unlock(®ister_lock); | |
51 | ||
52 | return t; | |
53 | } | |
54 | ||
55 | static struct dm_cache_policy_type *get_policy(const char *name) | |
56 | { | |
57 | struct dm_cache_policy_type *t; | |
58 | ||
59 | t = get_policy_once(name); | |
60 | if (IS_ERR(t)) | |
61 | return NULL; | |
62 | ||
63 | if (t) | |
64 | return t; | |
65 | ||
66 | request_module("dm-cache-%s", name); | |
67 | ||
68 | t = get_policy_once(name); | |
69 | if (IS_ERR(t)) | |
70 | return NULL; | |
71 | ||
72 | return t; | |
73 | } | |
74 | ||
75 | static void put_policy(struct dm_cache_policy_type *t) | |
76 | { | |
77 | module_put(t->owner); | |
78 | } | |
79 | ||
80 | int dm_cache_policy_register(struct dm_cache_policy_type *type) | |
81 | { | |
82 | int r; | |
83 | ||
84 | /* One size fits all for now */ | |
85 | if (type->hint_size != 0 && type->hint_size != 4) { | |
86 | DMWARN("hint size must be 0 or 4 but %llu supplied.", (unsigned long long) type->hint_size); | |
87 | return -EINVAL; | |
88 | } | |
89 | ||
90 | spin_lock(®ister_lock); | |
91 | if (__find_policy(type->name)) { | |
92 | DMWARN("attempt to register policy under duplicate name %s", type->name); | |
93 | r = -EINVAL; | |
94 | } else { | |
95 | list_add(&type->list, ®ister_list); | |
96 | r = 0; | |
97 | } | |
98 | spin_unlock(®ister_lock); | |
99 | ||
100 | return r; | |
101 | } | |
102 | EXPORT_SYMBOL_GPL(dm_cache_policy_register); | |
103 | ||
104 | void dm_cache_policy_unregister(struct dm_cache_policy_type *type) | |
105 | { | |
106 | spin_lock(®ister_lock); | |
107 | list_del_init(&type->list); | |
108 | spin_unlock(®ister_lock); | |
109 | } | |
110 | EXPORT_SYMBOL_GPL(dm_cache_policy_unregister); | |
111 | ||
112 | struct dm_cache_policy *dm_cache_policy_create(const char *name, | |
113 | dm_cblock_t cache_size, | |
114 | sector_t origin_size, | |
115 | sector_t cache_block_size) | |
116 | { | |
117 | struct dm_cache_policy *p = NULL; | |
118 | struct dm_cache_policy_type *type; | |
119 | ||
120 | type = get_policy(name); | |
121 | if (!type) { | |
122 | DMWARN("unknown policy type"); | |
4cb3e1db | 123 | return ERR_PTR(-EINVAL); |
c6b4fcba JT |
124 | } |
125 | ||
126 | p = type->create(cache_size, origin_size, cache_block_size); | |
127 | if (!p) { | |
128 | put_policy(type); | |
4cb3e1db | 129 | return ERR_PTR(-ENOMEM); |
c6b4fcba JT |
130 | } |
131 | p->private = type; | |
132 | ||
133 | return p; | |
134 | } | |
135 | EXPORT_SYMBOL_GPL(dm_cache_policy_create); | |
136 | ||
137 | void dm_cache_policy_destroy(struct dm_cache_policy *p) | |
138 | { | |
139 | struct dm_cache_policy_type *t = p->private; | |
140 | ||
141 | p->destroy(p); | |
142 | put_policy(t); | |
143 | } | |
144 | EXPORT_SYMBOL_GPL(dm_cache_policy_destroy); | |
145 | ||
146 | const char *dm_cache_policy_get_name(struct dm_cache_policy *p) | |
147 | { | |
148 | struct dm_cache_policy_type *t = p->private; | |
149 | ||
2e68c4e6 MS |
150 | /* if t->real is set then an alias was used (e.g. "default") */ |
151 | if (t->real) | |
152 | return t->real->name; | |
153 | ||
c6b4fcba JT |
154 | return t->name; |
155 | } | |
156 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_name); | |
157 | ||
86a3238c | 158 | const unsigned int *dm_cache_policy_get_version(struct dm_cache_policy *p) |
4e7f506f MS |
159 | { |
160 | struct dm_cache_policy_type *t = p->private; | |
161 | ||
162 | return t->version; | |
163 | } | |
164 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_version); | |
165 | ||
c6b4fcba JT |
166 | size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p) |
167 | { | |
168 | struct dm_cache_policy_type *t = p->private; | |
169 | ||
170 | return t->hint_size; | |
171 | } | |
172 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_hint_size); | |
173 | ||
174 | /*----------------------------------------------------------------*/ |