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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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34 if (argc != 2) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070035 ti->error = "Invalid argument count";
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 return -EINVAL;
37 }
38
39 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
40 if (lc == NULL) {
41 ti->error = "dm-linear: Cannot allocate linear context";
42 return -ENOMEM;
43 }
44
Mikulas Patocka31998ef2012-03-28 18:41:26 +010045 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 ti->error = "dm-linear: Invalid device sector";
47 goto bad;
48 }
Andrew Morton4ee218c2006-03-27 01:17:48 -080049 lc->start = tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Nikanth Karthikesan8215d6e2010-03-06 02:32:27 +000051 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 ti->error = "dm-linear: Device lookup failed";
53 goto bad;
54 }
55
Alasdair G Kergon55a62ee2013-03-01 22:45:47 +000056 ti->num_flush_bios = 1;
57 ti->num_discard_bios = 1;
58 ti->num_write_same_bios = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 ti->private = lc;
60 return 0;
61
62 bad:
63 kfree(lc);
64 return -EINVAL;
65}
66
67static void linear_dtr(struct dm_target *ti)
68{
69 struct linear_c *lc = (struct linear_c *) ti->private;
70
71 dm_put_device(ti, lc->dev);
72 kfree(lc);
73}
74
Milan Broz7bc34472008-07-21 12:00:38 +010075static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
76{
77 struct linear_c *lc = ti->private;
78
Alasdair G Kergonb441a2622010-08-12 04:14:11 +010079 return lc->start + dm_target_offset(ti, bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010080}
81
82static void linear_map_bio(struct dm_target *ti, struct bio *bio)
83{
84 struct linear_c *lc = ti->private;
85
86 bio->bi_bdev = lc->dev->bdev;
Mikulas Patocka433bcac2009-06-22 10:12:22 +010087 if (bio_sectors(bio))
88 bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010089}
90
Mikulas Patocka7de3ee52012-12-21 20:23:41 +000091static int linear_map(struct dm_target *ti, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
Milan Broz7bc34472008-07-21 12:00:38 +010093 linear_map_bio(ti, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Kiyoshi Uedad2a7ad22006-12-08 02:41:06 -080095 return DM_MAPIO_REMAPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096}
97
Mikulas Patockafd7c0922013-03-01 22:45:44 +000098static void linear_status(struct dm_target *ti, status_type_t type,
99 unsigned status_flags, char *result, unsigned maxlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100{
101 struct linear_c *lc = (struct linear_c *) ti->private;
102
103 switch (type) {
104 case STATUSTYPE_INFO:
105 result[0] = '\0';
106 break;
107
108 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -0800109 snprintf(result, maxlen, "%s %llu", lc->dev->name,
110 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 break;
112 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113}
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;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100119 struct dm_dev *dev = lc->dev;
120 int r = 0;
121
122 /*
123 * Only pass ioctls through if the device sizes match exactly.
124 */
125 if (lc->start ||
126 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
127 r = scsi_verify_blk_ioctl(NULL, cmd);
128
129 return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
Milan Brozab17ffa2006-10-03 01:15:18 -0700130}
131
Milan Broz7bc34472008-07-21 12:00:38 +0100132static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
133 struct bio_vec *biovec, int max_size)
134{
135 struct linear_c *lc = ti->private;
136 struct request_queue *q = bdev_get_queue(lc->dev->bdev);
137
138 if (!q->merge_bvec_fn)
139 return max_size;
140
141 bvm->bi_bdev = lc->dev->bdev;
142 bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
143
144 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
145}
146
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100147static int linear_iterate_devices(struct dm_target *ti,
148 iterate_devices_callout_fn fn, void *data)
149{
150 struct linear_c *lc = ti->private;
151
Mike Snitzer5dea2712009-07-23 20:30:42 +0100152 return fn(ti, lc->dev, lc->start, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100153}
154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155static struct target_type linear_target = {
156 .name = "linear",
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000157 .version = {1, 2, 1},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 .module = THIS_MODULE,
159 .ctr = linear_ctr,
160 .dtr = linear_dtr,
161 .map = linear_map,
162 .status = linear_status,
Milan Brozab17ffa2006-10-03 01:15:18 -0700163 .ioctl = linear_ioctl,
Milan Broz7bc34472008-07-21 12:00:38 +0100164 .merge = linear_merge,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100165 .iterate_devices = linear_iterate_devices,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166};
167
168int __init dm_linear_init(void)
169{
170 int r = dm_register_target(&linear_target);
171
172 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700173 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
175 return r;
176}
177
178void dm_linear_exit(void)
179{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000180 dm_unregister_target(&linear_target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181}