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