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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"
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/blkdev.h>
11#include <linux/bio.h>
12#include <linux/slab.h>
Mikulas Patocka586e80e2008-10-21 17:44:59 +010013#include <linux/device-mapper.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014
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
Mikulas Patocka433bcac2009-06-22 10:12:22 +010056 ti->num_flush_requests = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 ti->private = lc;
58 return 0;
59
60 bad:
61 kfree(lc);
62 return -EINVAL;
63}
64
65static void linear_dtr(struct dm_target *ti)
66{
67 struct linear_c *lc = (struct linear_c *) ti->private;
68
69 dm_put_device(ti, lc->dev);
70 kfree(lc);
71}
72
Milan Broz7bc34472008-07-21 12:00:38 +010073static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
74{
75 struct linear_c *lc = ti->private;
76
77 return lc->start + (bi_sector - ti->begin);
78}
79
80static void linear_map_bio(struct dm_target *ti, struct bio *bio)
81{
82 struct linear_c *lc = ti->private;
83
84 bio->bi_bdev = lc->dev->bdev;
Mikulas Patocka433bcac2009-06-22 10:12:22 +010085 if (bio_sectors(bio))
86 bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010087}
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089static int linear_map(struct dm_target *ti, struct bio *bio,
90 union map_info *map_context)
91{
Milan Broz7bc34472008-07-21 12:00:38 +010092 linear_map_bio(ti, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Kiyoshi Uedad2a7ad22006-12-08 02:41:06 -080094 return DM_MAPIO_REMAPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095}
96
97static int linear_status(struct dm_target *ti, status_type_t type,
98 char *result, unsigned int maxlen)
99{
100 struct linear_c *lc = (struct linear_c *) ti->private;
101
102 switch (type) {
103 case STATUSTYPE_INFO:
104 result[0] = '\0';
105 break;
106
107 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -0800108 snprintf(result, maxlen, "%s %llu", lc->dev->name,
109 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 break;
111 }
112 return 0;
113}
114
Al Viro647b3d02007-08-28 22:15:59 -0400115static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
Milan Brozab17ffa2006-10-03 01:15:18 -0700116 unsigned long arg)
117{
118 struct linear_c *lc = (struct linear_c *) ti->private;
Al Viro633a08b2007-08-29 20:34:12 -0400119 return __blkdev_driver_ioctl(lc->dev->bdev, lc->dev->mode, cmd, arg);
Milan Brozab17ffa2006-10-03 01:15:18 -0700120}
121
Milan Broz7bc34472008-07-21 12:00:38 +0100122static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
123 struct bio_vec *biovec, int max_size)
124{
125 struct linear_c *lc = ti->private;
126 struct request_queue *q = bdev_get_queue(lc->dev->bdev);
127
128 if (!q->merge_bvec_fn)
129 return max_size;
130
131 bvm->bi_bdev = lc->dev->bdev;
132 bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
133
134 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
135}
136
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100137static int linear_iterate_devices(struct dm_target *ti,
138 iterate_devices_callout_fn fn, void *data)
139{
140 struct linear_c *lc = ti->private;
141
Mike Snitzer5dea2712009-07-23 20:30:42 +0100142 return fn(ti, lc->dev, lc->start, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100143}
144
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145static struct target_type linear_target = {
146 .name = "linear",
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100147 .version = {1, 1, 0},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 .module = THIS_MODULE,
149 .ctr = linear_ctr,
150 .dtr = linear_dtr,
151 .map = linear_map,
152 .status = linear_status,
Milan Brozab17ffa2006-10-03 01:15:18 -0700153 .ioctl = linear_ioctl,
Milan Broz7bc34472008-07-21 12:00:38 +0100154 .merge = linear_merge,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100155 .iterate_devices = linear_iterate_devices,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156};
157
158int __init dm_linear_init(void)
159{
160 int r = dm_register_target(&linear_target);
161
162 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700163 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
165 return r;
166}
167
168void dm_linear_exit(void)
169{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000170 dm_unregister_target(&linear_target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171}