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  */
18 static 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 
26 static 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 
32 static 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 
38 static 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 
44 static 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 
51 static 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 
57 static 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 
65 static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
66 {
67 	p->remove_mapping(p, oblock);
68 }
69 
70 static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
71 {
72 	return p->remove_cblock(p, cblock);
73 }
74 
75 static 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 
81 static inline dm_cblock_t policy_residency(struct dm_cache_policy *p)
82 {
83 	return p->residency(p);
84 }
85 
86 static 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 
92 static 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 
104 static 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  */
115 static 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 
120 static 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 
126 static 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 
132 static 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  */
142 struct 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  */
150 void dm_cache_policy_destroy(struct dm_cache_policy *p);
151 
152 /*
153  * In case we've forgotten.
154  */
155 const char *dm_cache_policy_get_name(struct dm_cache_policy *p);
156 
157 const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p);
158 
159 size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);
160 
161 /*----------------------------------------------------------------*/
162 
163 #endif /* DM_CACHE_POLICY_INTERNAL_H */
164