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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;
Christoph Hellwigac62d622017-04-05 19:21:05 +020062 ti->num_write_zeroes_bios = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 ti->private = lc;
64 return 0;
65
66 bad:
67 kfree(lc);
Vivek Goyale80d1c82015-07-31 09:20:36 -040068 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069}
70
71static void linear_dtr(struct dm_target *ti)
72{
73 struct linear_c *lc = (struct linear_c *) ti->private;
74
75 dm_put_device(ti, lc->dev);
76 kfree(lc);
77}
78
Milan Broz7bc34472008-07-21 12:00:38 +010079static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
80{
81 struct linear_c *lc = ti->private;
82
Alasdair G Kergonb441a2622010-08-12 04:14:11 +010083 return lc->start + dm_target_offset(ti, bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010084}
85
86static void linear_map_bio(struct dm_target *ti, struct bio *bio)
87{
88 struct linear_c *lc = ti->private;
89
90 bio->bi_bdev = lc->dev->bdev;
Mikulas Patocka433bcac2009-06-22 10:12:22 +010091 if (bio_sectors(bio))
Kent Overstreet4f024f32013-10-11 15:44:27 -070092 bio->bi_iter.bi_sector =
93 linear_map_sector(ti, bio->bi_iter.bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010094}
95
Mikulas Patocka7de3ee52012-12-21 20:23:41 +000096static int linear_map(struct dm_target *ti, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
Milan Broz7bc34472008-07-21 12:00:38 +010098 linear_map_bio(ti, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
Kiyoshi Uedad2a7ad22006-12-08 02:41:06 -0800100 return DM_MAPIO_REMAPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101}
102
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000103static void linear_status(struct dm_target *ti, status_type_t type,
104 unsigned status_flags, char *result, unsigned maxlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105{
106 struct linear_c *lc = (struct linear_c *) ti->private;
107
108 switch (type) {
109 case STATUSTYPE_INFO:
110 result[0] = '\0';
111 break;
112
113 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -0800114 snprintf(result, maxlen, "%s %llu", lc->dev->name,
115 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 break;
117 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118}
119
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200120static int linear_prepare_ioctl(struct dm_target *ti,
121 struct block_device **bdev, fmode_t *mode)
Milan Brozab17ffa2006-10-03 01:15:18 -0700122{
123 struct linear_c *lc = (struct linear_c *) ti->private;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100124 struct dm_dev *dev = lc->dev;
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200125
126 *bdev = dev->bdev;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100127
128 /*
129 * Only pass ioctls through if the device sizes match exactly.
130 */
131 if (lc->start ||
132 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200133 return 1;
134 return 0;
Milan Brozab17ffa2006-10-03 01:15:18 -0700135}
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
Toshi Kani84b22f82016-06-22 17:54:54 -0600145static long linear_direct_access(struct dm_target *ti, sector_t sector,
Linus Torvaldsf0c98eb2016-07-28 17:22:07 -0700146 void **kaddr, pfn_t *pfn, long size)
Toshi Kani84b22f82016-06-22 17:54:54 -0600147{
148 struct linear_c *lc = ti->private;
149 struct block_device *bdev = lc->dev->bdev;
150 struct blk_dax_ctl dax = {
151 .sector = linear_map_sector(ti, sector),
152 .size = size,
153 };
154 long ret;
155
156 ret = bdev_direct_access(bdev, &dax);
157 *kaddr = dax.addr;
158 *pfn = dax.pfn;
159
160 return ret;
161}
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163static struct target_type linear_target = {
164 .name = "linear",
Toshi Kani84b22f82016-06-22 17:54:54 -0600165 .version = {1, 3, 0},
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 .module = THIS_MODULE,
167 .ctr = linear_ctr,
168 .dtr = linear_dtr,
169 .map = linear_map,
170 .status = linear_status,
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200171 .prepare_ioctl = linear_prepare_ioctl,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100172 .iterate_devices = linear_iterate_devices,
Toshi Kani84b22f82016-06-22 17:54:54 -0600173 .direct_access = linear_direct_access,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174};
175
176int __init dm_linear_init(void)
177{
178 int r = dm_register_target(&linear_target);
179
180 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700181 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183 return r;
184}
185
186void dm_linear_exit(void)
187{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000188 dm_unregister_target(&linear_target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189}