1 /*
2 * Copyright (C) 2001-2003 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/blkdev.h>
12 #include <linux/bio.h>
13 #include <linux/slab.h>
14
15 /*
16 * Linear: maps a linear range of a device.
17 */
18 struct linear_c {
19 struct dm_dev *dev;
20 sector_t start;
21 };
22
23 /*
24 * Construct a linear mapping: <dev_path> <offset>
25 */
26 static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
27 {
28 struct linear_c *lc;
29 unsigned long long tmp;
30
31 if (argc != 2) {
32 ti->error = "dm-linear: Invalid argument count";
33 return -EINVAL;
34 }
35
36 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
37 if (lc == NULL) {
38 ti->error = "dm-linear: Cannot allocate linear context";
39 return -ENOMEM;
40 }
41
42 if (sscanf(argv[1], "%llu", &tmp) != 1) {
43 ti->error = "dm-linear: Invalid device sector";
44 goto bad;
45 }
46 lc->start = tmp;
47
48 if (dm_get_device(ti, argv[0], lc->start, ti->len,
49 dm_table_get_mode(ti->table), &lc->dev)) {
50 ti->error = "dm-linear: Device lookup failed";
51 goto bad;
52 }
53
54 ti->private = lc;
55 return 0;
56
57 bad:
58 kfree(lc);
59 return -EINVAL;
60 }
61
62 static void linear_dtr(struct dm_target *ti)
63 {
64 struct linear_c *lc = (struct linear_c *) ti->private;
65
66 dm_put_device(ti, lc->dev);
67 kfree(lc);
68 }
69
70 static int linear_map(struct dm_target *ti, struct bio *bio,
71 union map_info *map_context)
72 {
73 struct linear_c *lc = (struct linear_c *) ti->private;
74
75 bio->bi_bdev = lc->dev->bdev;
76 bio->bi_sector = lc->start + (bio->bi_sector - ti->begin);
77
78 return 1;
79 }
80
81 static int linear_status(struct dm_target *ti, status_type_t type,
82 char *result, unsigned int maxlen)
83 {
84 struct linear_c *lc = (struct linear_c *) ti->private;
85
86 switch (type) {
87 case STATUSTYPE_INFO:
88 result[0] = '\0';
89 break;
90
91 case STATUSTYPE_TABLE:
92 snprintf(result, maxlen, "%s %llu", lc->dev->name,
93 (unsigned long long)lc->start);
94 break;
95 }
96 return 0;
97 }
98
99 static struct target_type linear_target = {
100 .name = "linear",
101 .version= {1, 0, 1},
102 .module = THIS_MODULE,
103 .ctr = linear_ctr,
104 .dtr = linear_dtr,
105 .map = linear_map,
106 .status = linear_status,
107 };
108
109 int __init dm_linear_init(void)
110 {
111 int r = dm_register_target(&linear_target);
112
113 if (r < 0)
114 DMERR("linear: register failed %d", r);
115
116 return r;
117 }
118
119 void dm_linear_exit(void)
120 {
121 int r = dm_unregister_target(&linear_target);
122
123 if (r < 0)
124 DMERR("linear: unregister failed %d", r);
125 }
126
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