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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;
Mikulas Patocka31998ef2012-03-28 18:41:26 +010032 char dummy;
Vivek Goyale80d1c82015-07-31 09:20:36 -040033 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
35 if (argc != 2) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070036 ti->error = "Invalid argument count";
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 return -EINVAL;
38 }
39
40 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
41 if (lc == NULL) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090042 ti->error = "Cannot allocate linear context";
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 return -ENOMEM;
44 }
45
Vivek Goyale80d1c82015-07-31 09:20:36 -040046 ret = -EINVAL;
Mikulas Patocka31998ef2012-03-28 18:41:26 +010047 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090048 ti->error = "Invalid device sector";
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 goto bad;
50 }
Andrew Morton4ee218c2006-03-27 01:17:48 -080051 lc->start = tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
Vivek Goyale80d1c82015-07-31 09:20:36 -040053 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
54 if (ret) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090055 ti->error = "Device lookup failed";
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 goto bad;
57 }
58
Alasdair G Kergon55a62ee2013-03-01 22:45:47 +000059 ti->num_flush_bios = 1;
60 ti->num_discard_bios = 1;
61 ti->num_write_same_bios = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 ti->private = lc;
63 return 0;
64
65 bad:
66 kfree(lc);
Vivek Goyale80d1c82015-07-31 09:20:36 -040067 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068}
69
70static void linear_dtr(struct dm_target *ti)
71{
72 struct linear_c *lc = (struct linear_c *) ti->private;
73
74 dm_put_device(ti, lc->dev);
75 kfree(lc);
76}
77
Milan Broz7bc34472008-07-21 12:00:38 +010078static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
79{
80 struct linear_c *lc = ti->private;
81
Alasdair G Kergonb441a2622010-08-12 04:14:11 +010082 return lc->start + dm_target_offset(ti, bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010083}
84
85static void linear_map_bio(struct dm_target *ti, struct bio *bio)
86{
87 struct linear_c *lc = ti->private;
88
89 bio->bi_bdev = lc->dev->bdev;
Mikulas Patocka433bcac2009-06-22 10:12:22 +010090 if (bio_sectors(bio))
Kent Overstreet4f024f32013-10-11 15:44:27 -070091 bio->bi_iter.bi_sector =
92 linear_map_sector(ti, bio->bi_iter.bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010093}
94
Mikulas Patocka7de3ee52012-12-21 20:23:41 +000095static int linear_map(struct dm_target *ti, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
Milan Broz7bc34472008-07-21 12:00:38 +010097 linear_map_bio(ti, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
Kiyoshi Uedad2a7ad22006-12-08 02:41:06 -080099 return DM_MAPIO_REMAPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100}
101
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000102static void linear_status(struct dm_target *ti, status_type_t type,
103 unsigned status_flags, char *result, unsigned maxlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
105 struct linear_c *lc = (struct linear_c *) ti->private;
106
107 switch (type) {
108 case STATUSTYPE_INFO:
109 result[0] = '\0';
110 break;
111
112 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -0800113 snprintf(result, maxlen, "%s %llu", lc->dev->name,
114 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 break;
116 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117}
118
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200119static int linear_prepare_ioctl(struct dm_target *ti,
120 struct block_device **bdev, fmode_t *mode)
Milan Brozab17ffa2006-10-03 01:15:18 -0700121{
122 struct linear_c *lc = (struct linear_c *) ti->private;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100123 struct dm_dev *dev = lc->dev;
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200124
125 *bdev = dev->bdev;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100126
127 /*
128 * Only pass ioctls through if the device sizes match exactly.
129 */
130 if (lc->start ||
131 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200132 return 1;
133 return 0;
Milan Brozab17ffa2006-10-03 01:15:18 -0700134}
135
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100136static int linear_iterate_devices(struct dm_target *ti,
137 iterate_devices_callout_fn fn, void *data)
138{
139 struct linear_c *lc = ti->private;
140
Mike Snitzer5dea2712009-07-23 20:30:42 +0100141 return fn(ti, lc->dev, lc->start, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100142}
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144static struct target_type linear_target = {
145 .name = "linear",
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000146 .version = {1, 2, 1},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 .module = THIS_MODULE,
148 .ctr = linear_ctr,
149 .dtr = linear_dtr,
150 .map = linear_map,
151 .status = linear_status,
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200152 .prepare_ioctl = linear_prepare_ioctl,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100153 .iterate_devices = linear_iterate_devices,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154};
155
156int __init dm_linear_init(void)
157{
158 int r = dm_register_target(&linear_target);
159
160 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700161 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163 return r;
164}
165
166void dm_linear_exit(void)
167{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000168 dm_unregister_target(&linear_target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169}