blob: 47b3c62bbdb8839086466a60439a0651758acd52 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Alasdair G Kergon72d94862006-06-26 00:27:35 -070015#define DM_MSG_PREFIX "linear"
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017/*
18 * Linear: maps a linear range of a device.
19 */
20struct linear_c {
21 struct dm_dev *dev;
22 sector_t start;
23};
24
25/*
26 * Construct a linear mapping: <dev_path> <offset>
27 */
28static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
29{
30 struct linear_c *lc;
Andrew Morton4ee218c2006-03-27 01:17:48 -080031 unsigned long long tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33 if (argc != 2) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070034 ti->error = "Invalid argument count";
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 return -EINVAL;
36 }
37
38 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
39 if (lc == NULL) {
40 ti->error = "dm-linear: Cannot allocate linear context";
41 return -ENOMEM;
42 }
43
Andrew Morton4ee218c2006-03-27 01:17:48 -080044 if (sscanf(argv[1], "%llu", &tmp) != 1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 ti->error = "dm-linear: Invalid device sector";
46 goto bad;
47 }
Andrew Morton4ee218c2006-03-27 01:17:48 -080048 lc->start = tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50 if (dm_get_device(ti, argv[0], lc->start, ti->len,
51 dm_table_get_mode(ti->table), &lc->dev)) {
52 ti->error = "dm-linear: Device lookup failed";
53 goto bad;
54 }
55
56 ti->private = lc;
57 return 0;
58
59 bad:
60 kfree(lc);
61 return -EINVAL;
62}
63
64static void linear_dtr(struct dm_target *ti)
65{
66 struct linear_c *lc = (struct linear_c *) ti->private;
67
68 dm_put_device(ti, lc->dev);
69 kfree(lc);
70}
71
72static int linear_map(struct dm_target *ti, struct bio *bio,
73 union map_info *map_context)
74{
75 struct linear_c *lc = (struct linear_c *) ti->private;
76
77 bio->bi_bdev = lc->dev->bdev;
78 bio->bi_sector = lc->start + (bio->bi_sector - ti->begin);
79
80 return 1;
81}
82
83static int linear_status(struct dm_target *ti, status_type_t type,
84 char *result, unsigned int maxlen)
85{
86 struct linear_c *lc = (struct linear_c *) ti->private;
87
88 switch (type) {
89 case STATUSTYPE_INFO:
90 result[0] = '\0';
91 break;
92
93 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -080094 snprintf(result, maxlen, "%s %llu", lc->dev->name,
95 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 break;
97 }
98 return 0;
99}
100
101static struct target_type linear_target = {
102 .name = "linear",
103 .version= {1, 0, 1},
104 .module = THIS_MODULE,
105 .ctr = linear_ctr,
106 .dtr = linear_dtr,
107 .map = linear_map,
108 .status = linear_status,
109};
110
111int __init dm_linear_init(void)
112{
113 int r = dm_register_target(&linear_target);
114
115 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700116 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
118 return r;
119}
120
121void dm_linear_exit(void)
122{
123 int r = dm_unregister_target(&linear_target);
124
125 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700126 DMERR("unregister failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127}