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

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