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1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm.h"
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/kmod.h>
12#include <linux/bio.h>
13
14#define DM_MSG_PREFIX "target"
15
16static LIST_HEAD(_targets);
17static DECLARE_RWSEM(_lock);
18
19#define DM_MOD_NAME_SIZE 32
20
21static inline struct target_type *__find_target_type(const char *name)
22{
23 struct target_type *tt;
24
25 list_for_each_entry(tt, &_targets, list)
26 if (!strcmp(name, tt->name))
27 return tt;
28
29 return NULL;
30}
31
32static struct target_type *get_target_type(const char *name)
33{
34 struct target_type *tt;
35
36 down_read(&_lock);
37
38 tt = __find_target_type(name);
39 if (tt && !try_module_get(tt->module))
40 tt = NULL;
41
42 up_read(&_lock);
43 return tt;
44}
45
46static void load_module(const char *name)
47{
48 request_module("dm-%s", name);
49}
50
51struct target_type *dm_get_target_type(const char *name)
52{
53 struct target_type *tt = get_target_type(name);
54
55 if (!tt) {
56 load_module(name);
57 tt = get_target_type(name);
58 }
59
60 return tt;
61}
62
63void dm_put_target_type(struct target_type *tt)
64{
65 down_read(&_lock);
66 module_put(tt->module);
67 up_read(&_lock);
68}
69
70int dm_target_iterate(void (*iter_func)(struct target_type *tt,
71 void *param), void *param)
72{
73 struct target_type *tt;
74
75 down_read(&_lock);
76 list_for_each_entry(tt, &_targets, list)
77 iter_func(tt, param);
78 up_read(&_lock);
79
80 return 0;
81}
82
83int dm_register_target(struct target_type *tt)
84{
85 int rv = 0;
86
87 down_write(&_lock);
88 if (__find_target_type(tt->name))
89 rv = -EEXIST;
90 else
91 list_add(&tt->list, &_targets);
92
93 up_write(&_lock);
94 return rv;
95}
96
97void dm_unregister_target(struct target_type *tt)
98{
99 down_write(&_lock);
100 if (!__find_target_type(tt->name)) {
101 DMCRIT("Unregistering unrecognised target: %s", tt->name);
102 BUG();
103 }
104
105 list_del(&tt->list);
106
107 up_write(&_lock);
108}
109
110/*
111 * io-err: always fails an io, useful for bringing
112 * up LVs that have holes in them.
113 */
114static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
115{
116 /*
117 * Return error for discards instead of -EOPNOTSUPP
118 */
119 tt->num_discard_requests = 1;
120
121 return 0;
122}
123
124static void io_err_dtr(struct dm_target *tt)
125{
126 /* empty */
127}
128
129static int io_err_map(struct dm_target *tt, struct bio *bio,
130 union map_info *map_context)
131{
132 return -EIO;
133}
134
135static struct target_type error_target = {
136 .name = "error",
137 .version = {1, 0, 1},
138 .ctr = io_err_ctr,
139 .dtr = io_err_dtr,
140 .map = io_err_map,
141};
142
143int __init dm_target_init(void)
144{
145 return dm_register_target(&error_target);
146}
147
148void dm_target_exit(void)
149{
150 dm_unregister_target(&error_target);
151}
152
153EXPORT_SYMBOL(dm_register_target);
154EXPORT_SYMBOL(dm_unregister_target);
1/*
2 * Copyright (C) 2001 Sistina Software (UK) Limited
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-core.h"
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/kmod.h>
12#include <linux/bio.h>
13
14#define DM_MSG_PREFIX "target"
15
16static LIST_HEAD(_targets);
17static DECLARE_RWSEM(_lock);
18
19static inline struct target_type *__find_target_type(const char *name)
20{
21 struct target_type *tt;
22
23 list_for_each_entry(tt, &_targets, list)
24 if (!strcmp(name, tt->name))
25 return tt;
26
27 return NULL;
28}
29
30static struct target_type *get_target_type(const char *name)
31{
32 struct target_type *tt;
33
34 down_read(&_lock);
35
36 tt = __find_target_type(name);
37 if (tt && !try_module_get(tt->module))
38 tt = NULL;
39
40 up_read(&_lock);
41 return tt;
42}
43
44static void load_module(const char *name)
45{
46 request_module("dm-%s", name);
47}
48
49struct target_type *dm_get_target_type(const char *name)
50{
51 struct target_type *tt = get_target_type(name);
52
53 if (!tt) {
54 load_module(name);
55 tt = get_target_type(name);
56 }
57
58 return tt;
59}
60
61void dm_put_target_type(struct target_type *tt)
62{
63 down_read(&_lock);
64 module_put(tt->module);
65 up_read(&_lock);
66}
67
68int dm_target_iterate(void (*iter_func)(struct target_type *tt,
69 void *param), void *param)
70{
71 struct target_type *tt;
72
73 down_read(&_lock);
74 list_for_each_entry(tt, &_targets, list)
75 iter_func(tt, param);
76 up_read(&_lock);
77
78 return 0;
79}
80
81int dm_register_target(struct target_type *tt)
82{
83 int rv = 0;
84
85 down_write(&_lock);
86 if (__find_target_type(tt->name))
87 rv = -EEXIST;
88 else
89 list_add(&tt->list, &_targets);
90
91 up_write(&_lock);
92 return rv;
93}
94
95void dm_unregister_target(struct target_type *tt)
96{
97 down_write(&_lock);
98 if (!__find_target_type(tt->name)) {
99 DMCRIT("Unregistering unrecognised target: %s", tt->name);
100 BUG();
101 }
102
103 list_del(&tt->list);
104
105 up_write(&_lock);
106}
107
108/*
109 * io-err: always fails an io, useful for bringing
110 * up LVs that have holes in them.
111 */
112static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
113{
114 /*
115 * Return error for discards instead of -EOPNOTSUPP
116 */
117 tt->num_discard_bios = 1;
118
119 return 0;
120}
121
122static void io_err_dtr(struct dm_target *tt)
123{
124 /* empty */
125}
126
127static int io_err_map(struct dm_target *tt, struct bio *bio)
128{
129 return DM_MAPIO_KILL;
130}
131
132static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
133 union map_info *map_context,
134 struct request **clone)
135{
136 return DM_MAPIO_KILL;
137}
138
139static void io_err_release_clone_rq(struct request *clone,
140 union map_info *map_context)
141{
142}
143
144static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
145 long nr_pages, void **kaddr, pfn_t *pfn)
146{
147 return -EIO;
148}
149
150static struct target_type error_target = {
151 .name = "error",
152 .version = {1, 5, 0},
153 .features = DM_TARGET_WILDCARD,
154 .ctr = io_err_ctr,
155 .dtr = io_err_dtr,
156 .map = io_err_map,
157 .clone_and_map_rq = io_err_clone_and_map_rq,
158 .release_clone_rq = io_err_release_clone_rq,
159 .direct_access = io_err_dax_direct_access,
160};
161
162int __init dm_target_init(void)
163{
164 return dm_register_target(&error_target);
165}
166
167void dm_target_exit(void)
168{
169 dm_unregister_target(&error_target);
170}
171
172EXPORT_SYMBOL(dm_register_target);
173EXPORT_SYMBOL(dm_unregister_target);