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