2 * Copyright (C) 2001 Sistina Software (UK) Limited
4 * This file is released under the GPL.
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/kmod.h>
12 #include <linux/bio.h>
13 #include <linux/slab.h>
15 #define DM_MSG_PREFIX "target"
18 struct target_type tt;
20 struct list_head list;
23 static LIST_HEAD(_targets);
24 static DECLARE_RWSEM(_lock);
26 #define DM_MOD_NAME_SIZE 32
28 static inline struct tt_internal *__find_target_type(const char *name)
30 struct tt_internal *ti;
32 list_for_each_entry (ti, &_targets, list)
33 if (!strcmp(name, ti->tt.name))
39 static struct tt_internal *get_target_type(const char *name)
41 struct tt_internal *ti;
45 ti = __find_target_type(name);
46 if (ti && !try_module_get(ti->tt.module))
53 static void load_module(const char *name)
55 request_module("dm-%s", name);
58 struct target_type *dm_get_target_type(const char *name)
60 struct tt_internal *ti = get_target_type(name);
64 ti = get_target_type(name);
67 return ti ? &ti->tt : NULL;
70 void dm_put_target_type(struct target_type *t)
72 struct tt_internal *ti = (struct tt_internal *) t;
75 module_put(ti->tt.module);
81 static struct tt_internal *alloc_target(struct target_type *t)
83 struct tt_internal *ti = kzalloc(sizeof(*ti), GFP_KERNEL);
92 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
93 void *param), void *param)
95 struct tt_internal *ti;
98 list_for_each_entry (ti, &_targets, list)
99 iter_func(&ti->tt, param);
105 int dm_register_target(struct target_type *t)
108 struct tt_internal *ti = alloc_target(t);
114 if (__find_target_type(t->name))
117 list_add(&ti->list, &_targets);
125 void dm_unregister_target(struct target_type *t)
127 struct tt_internal *ti;
130 if (!(ti = __find_target_type(t->name))) {
131 DMCRIT("Unregistering unrecognised target: %s", t->name);
142 * io-err: always fails an io, useful for bringing
143 * up LVs that have holes in them.
145 static int io_err_ctr(struct dm_target *ti, unsigned int argc, char **args)
150 static void io_err_dtr(struct dm_target *ti)
155 static int io_err_map(struct dm_target *ti, struct bio *bio,
156 union map_info *map_context)
161 static struct target_type error_target = {
163 .version = {1, 0, 1},
169 int __init dm_target_init(void)
171 return dm_register_target(&error_target);
174 void dm_target_exit(void)
176 dm_unregister_target(&error_target);
179 EXPORT_SYMBOL(dm_register_target);
180 EXPORT_SYMBOL(dm_unregister_target);