1/*
  2 * Copyright (C) 2012 Red Hat. All rights reserved.
  3 *
  4 * This file is released under the GPL.
  5 */
  6
  7#ifndef DM_CACHE_POLICY_INTERNAL_H
  8#define DM_CACHE_POLICY_INTERNAL_H
  9
 10#include <linux/vmalloc.h>
 11#include "dm-cache-policy.h"
 12
 13/*----------------------------------------------------------------*/
 14
 15/*
 16 * Little inline functions that simplify calling the policy methods.
 17 */
 18static inline int policy_map(struct dm_cache_policy *p, dm_oblock_t oblock,
 19			     bool can_block, bool can_migrate, bool discarded_oblock,
 20			     struct bio *bio, struct policy_locker *locker,
 21			     struct policy_result *result)
 22{
 23	return p->map(p, oblock, can_block, can_migrate, discarded_oblock, bio, locker, result);
 24}
 25
 26static inline int policy_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
 27{
 28	BUG_ON(!p->lookup);
 29	return p->lookup(p, oblock, cblock);
 30}
 31
 32static inline void policy_set_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
 33{
 34	if (p->set_dirty)
 35		p->set_dirty(p, oblock);
 36}
 37
 38static inline void policy_clear_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
 39{
 40	if (p->clear_dirty)
 41		p->clear_dirty(p, oblock);
 42}
 43
 44static inline int policy_load_mapping(struct dm_cache_policy *p,
 45				      dm_oblock_t oblock, dm_cblock_t cblock,
 46				      uint32_t hint, bool hint_valid)
 47{
 48	return p->load_mapping(p, oblock, cblock, hint, hint_valid);
 49}
 50
 51static inline int policy_walk_mappings(struct dm_cache_policy *p,
 52				      policy_walk_fn fn, void *context)
 53{
 54	return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0;
 55}
 56
 57static inline int policy_writeback_work(struct dm_cache_policy *p,
 58					dm_oblock_t *oblock,
 59					dm_cblock_t *cblock,
 60					bool critical_only)
 61{
 62	return p->writeback_work ? p->writeback_work(p, oblock, cblock, critical_only) : -ENOENT;
 63}
 64
 65static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
 66{
 67	p->remove_mapping(p, oblock);
 68}
 69
 70static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
 71{
 72	return p->remove_cblock(p, cblock);
 73}
 74
 75static inline void policy_force_mapping(struct dm_cache_policy *p,
 76					dm_oblock_t current_oblock, dm_oblock_t new_oblock)
 77{
 78	return p->force_mapping(p, current_oblock, new_oblock);
 79}
 80
 81static inline dm_cblock_t policy_residency(struct dm_cache_policy *p)
 82{
 83	return p->residency(p);
 84}
 85
 86static inline void policy_tick(struct dm_cache_policy *p, bool can_block)
 87{
 88	if (p->tick)
 89		return p->tick(p, can_block);
 90}
 91
 92static inline int policy_emit_config_values(struct dm_cache_policy *p, char *result,
 93					    unsigned maxlen, ssize_t *sz_ptr)
 94{
 95	ssize_t sz = *sz_ptr;
 96	if (p->emit_config_values)
 97		return p->emit_config_values(p, result, maxlen, sz_ptr);
 98
 99	DMEMIT("0 ");
100	*sz_ptr = sz;
101	return 0;
102}
103
104static inline int policy_set_config_value(struct dm_cache_policy *p,
105					  const char *key, const char *value)
106{
107	return p->set_config_value ? p->set_config_value(p, key, value) : -EINVAL;
108}
109
110/*----------------------------------------------------------------*/
111
112/*
113 * Some utility functions commonly used by policies and the core target.
114 */
115static inline size_t bitset_size_in_bytes(unsigned nr_entries)
116{
117	return sizeof(unsigned long) * dm_div_up(nr_entries, BITS_PER_LONG);
118}
119
120static inline unsigned long *alloc_bitset(unsigned nr_entries)
121{
122	size_t s = bitset_size_in_bytes(nr_entries);
123	return vzalloc(s);
124}
125
126static inline void clear_bitset(void *bitset, unsigned nr_entries)
127{
128	size_t s = bitset_size_in_bytes(nr_entries);
129	memset(bitset, 0, s);
130}
131
132static inline void free_bitset(unsigned long *bits)
133{
134	vfree(bits);
135}
136
137/*----------------------------------------------------------------*/
138
139/*
140 * Creates a new cache policy given a policy name, a cache size, an origin size and the block size.
141 */
142struct dm_cache_policy *dm_cache_policy_create(const char *name, dm_cblock_t cache_size,
143					       sector_t origin_size, sector_t block_size);
144
145/*
146 * Destroys the policy.  This drops references to the policy module as well
147 * as calling it's destroy method.  So always use this rather than calling
148 * the policy->destroy method directly.
149 */
150void dm_cache_policy_destroy(struct dm_cache_policy *p);
151
152/*
153 * In case we've forgotten.
154 */
155const char *dm_cache_policy_get_name(struct dm_cache_policy *p);
156
157const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p);
158
159size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);
160
161/*----------------------------------------------------------------*/
162
163#endif /* DM_CACHE_POLICY_INTERNAL_H */