Heinz Mauelshagen | 3bd9400 | 2023-01-25 21:00:44 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 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"); |
Mikulas Patocka | 4cb3e1d | 2013-10-01 18:35:39 -0400 | [diff] [blame] | 123 | return ERR_PTR(-EINVAL); |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 124 | } |
| 125 | |
| 126 | p = type->create(cache_size, origin_size, cache_block_size); |
| 127 | if (!p) { |
| 128 | put_policy(type); |
Mikulas Patocka | 4cb3e1d | 2013-10-01 18:35:39 -0400 | [diff] [blame] | 129 | return ERR_PTR(-ENOMEM); |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 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 | |
Mike Snitzer | 2e68c4e | 2014-01-15 21:06:55 -0500 | [diff] [blame] | 150 | /* if t->real is set then an alias was used (e.g. "default") */ |
| 151 | if (t->real) |
| 152 | return t->real->name; |
| 153 | |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 154 | return t->name; |
| 155 | } |
| 156 | EXPORT_SYMBOL_GPL(dm_cache_policy_get_name); |
| 157 | |
Heinz Mauelshagen | 86a3238 | 2023-01-25 21:14:58 +0100 | [diff] [blame] | 158 | const unsigned int *dm_cache_policy_get_version(struct dm_cache_policy *p) |
Mike Snitzer | 4e7f506 | 2013-03-20 17:21:27 +0000 | [diff] [blame] | 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 | |
Joe Thornber | c6b4fcb | 2013-03-01 22:45:51 +0000 | [diff] [blame] | 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 | /*----------------------------------------------------------------*/ |