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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>
Dan Williams817bf402017-04-12 13:37:44 -070012#include <linux/dax.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/slab.h>
Mikulas Patocka586e80e2008-10-21 17:44:59 +010014#include <linux/device-mapper.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
Alasdair G Kergon72d94862006-06-26 00:27:35 -070016#define DM_MSG_PREFIX "linear"
17
Linus Torvalds1da177e2005-04-16 15:20:36 -070018/*
19 * Linear: maps a linear range of a device.
20 */
21struct linear_c {
22 struct dm_dev *dev;
23 sector_t start;
24};
25
26/*
27 * Construct a linear mapping: <dev_path> <offset>
28 */
29static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
30{
31 struct linear_c *lc;
Andrew Morton4ee218c2006-03-27 01:17:48 -080032 unsigned long long tmp;
Mikulas Patocka31998ef2012-03-28 18:41:26 +010033 char dummy;
Vivek Goyale80d1c82015-07-31 09:20:36 -040034 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36 if (argc != 2) {
Alasdair G Kergon72d94862006-06-26 00:27:35 -070037 ti->error = "Invalid argument count";
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 return -EINVAL;
39 }
40
41 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
42 if (lc == NULL) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090043 ti->error = "Cannot allocate linear context";
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 return -ENOMEM;
45 }
46
Vivek Goyale80d1c82015-07-31 09:20:36 -040047 ret = -EINVAL;
Mikulas Patocka31998ef2012-03-28 18:41:26 +010048 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090049 ti->error = "Invalid device sector";
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 goto bad;
51 }
Andrew Morton4ee218c2006-03-27 01:17:48 -080052 lc->start = tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Vivek Goyale80d1c82015-07-31 09:20:36 -040054 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
55 if (ret) {
Tomohiro Kusumi00272c82015-10-28 04:38:58 +090056 ti->error = "Device lookup failed";
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 goto bad;
58 }
59
Alasdair G Kergon55a62ee2013-03-01 22:45:47 +000060 ti->num_flush_bios = 1;
61 ti->num_discard_bios = 1;
62 ti->num_write_same_bios = 1;
Christoph Hellwigac62d622017-04-05 19:21:05 +020063 ti->num_write_zeroes_bios = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 ti->private = lc;
65 return 0;
66
67 bad:
68 kfree(lc);
Vivek Goyale80d1c82015-07-31 09:20:36 -040069 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070}
71
72static void linear_dtr(struct dm_target *ti)
73{
74 struct linear_c *lc = (struct linear_c *) ti->private;
75
76 dm_put_device(ti, lc->dev);
77 kfree(lc);
78}
79
Milan Broz7bc34472008-07-21 12:00:38 +010080static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
81{
82 struct linear_c *lc = ti->private;
83
Alasdair G Kergonb441a2622010-08-12 04:14:11 +010084 return lc->start + dm_target_offset(ti, bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010085}
86
87static void linear_map_bio(struct dm_target *ti, struct bio *bio)
88{
89 struct linear_c *lc = ti->private;
90
Christoph Hellwig74d46992017-08-23 19:10:32 +020091 bio_set_dev(bio, lc->dev->bdev);
Damien Le Moal0be12c12017-05-08 16:40:50 -070092 if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)
Kent Overstreet4f024f32013-10-11 15:44:27 -070093 bio->bi_iter.bi_sector =
94 linear_map_sector(ti, bio->bi_iter.bi_sector);
Milan Broz7bc34472008-07-21 12:00:38 +010095}
96
Mikulas Patocka7de3ee52012-12-21 20:23:41 +000097static int linear_map(struct dm_target *ti, struct bio *bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
Milan Broz7bc34472008-07-21 12:00:38 +010099 linear_map_bio(ti, bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
Kiyoshi Uedad2a7ad22006-12-08 02:41:06 -0800101 return DM_MAPIO_REMAPPED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102}
103
Damien Le Moalc339fab2018-10-11 11:45:30 +0900104#ifdef CONFIG_BLK_DEV_ZONED
Damien Le Moal0be12c12017-05-08 16:40:50 -0700105static int linear_end_io(struct dm_target *ti, struct bio *bio,
106 blk_status_t *error)
107{
108 struct linear_c *lc = ti->private;
109
110 if (!*error && bio_op(bio) == REQ_OP_ZONE_REPORT)
111 dm_remap_zone_report(ti, bio, lc->start);
112
113 return DM_ENDIO_DONE;
114}
Mike Snitzerefd65372018-10-10 12:01:55 -0400115#endif
Damien Le Moal0be12c12017-05-08 16:40:50 -0700116
Mikulas Patockafd7c0922013-03-01 22:45:44 +0000117static void linear_status(struct dm_target *ti, status_type_t type,
118 unsigned status_flags, char *result, unsigned maxlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
120 struct linear_c *lc = (struct linear_c *) ti->private;
121
122 switch (type) {
123 case STATUSTYPE_INFO:
124 result[0] = '\0';
125 break;
126
127 case STATUSTYPE_TABLE:
Andrew Morton4ee218c2006-03-27 01:17:48 -0800128 snprintf(result, maxlen, "%s %llu", lc->dev->name,
129 (unsigned long long)lc->start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 break;
131 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132}
133
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200134static int linear_prepare_ioctl(struct dm_target *ti,
135 struct block_device **bdev, fmode_t *mode)
Milan Brozab17ffa2006-10-03 01:15:18 -0700136{
137 struct linear_c *lc = (struct linear_c *) ti->private;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100138 struct dm_dev *dev = lc->dev;
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200139
140 *bdev = dev->bdev;
Paolo Bonziniec8013b2012-01-12 16:01:29 +0100141
142 /*
143 * Only pass ioctls through if the device sizes match exactly.
144 */
145 if (lc->start ||
146 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200147 return 1;
148 return 0;
Milan Brozab17ffa2006-10-03 01:15:18 -0700149}
150
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100151static int linear_iterate_devices(struct dm_target *ti,
152 iterate_devices_callout_fn fn, void *data)
153{
154 struct linear_c *lc = ti->private;
155
Mike Snitzer5dea2712009-07-23 20:30:42 +0100156 return fn(ti, lc->dev, lc->start, ti->len, data);
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100157}
158
Dan Williams817bf402017-04-12 13:37:44 -0700159static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
160 long nr_pages, void **kaddr, pfn_t *pfn)
Toshi Kani84b22f82016-06-22 17:54:54 -0600161{
Dan Williams817bf402017-04-12 13:37:44 -0700162 long ret;
Toshi Kani84b22f82016-06-22 17:54:54 -0600163 struct linear_c *lc = ti->private;
164 struct block_device *bdev = lc->dev->bdev;
Dan Williams817bf402017-04-12 13:37:44 -0700165 struct dax_device *dax_dev = lc->dev->dax_dev;
166 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
Toshi Kani84b22f82016-06-22 17:54:54 -0600167
Dan Williams817bf402017-04-12 13:37:44 -0700168 dev_sector = linear_map_sector(ti, sector);
169 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
170 if (ret)
171 return ret;
172 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
Toshi Kani84b22f82016-06-22 17:54:54 -0600173}
174
Dan Williams7e026c82017-05-29 12:57:56 -0700175static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
176 void *addr, size_t bytes, struct iov_iter *i)
177{
178 struct linear_c *lc = ti->private;
179 struct block_device *bdev = lc->dev->bdev;
180 struct dax_device *dax_dev = lc->dev->dax_dev;
181 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
182
183 dev_sector = linear_map_sector(ti, sector);
184 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
185 return 0;
186 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
187}
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189static struct target_type linear_target = {
190 .name = "linear",
Damien Le Moal0be12c12017-05-08 16:40:50 -0700191 .version = {1, 4, 0},
Damien Le Moalc339fab2018-10-11 11:45:30 +0900192#ifdef CONFIG_BLK_DEV_ZONED
Mike Snitzerefd65372018-10-10 12:01:55 -0400193 .end_io = linear_end_io,
Damien Le Moal0be12c12017-05-08 16:40:50 -0700194 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
Mike Snitzerefd65372018-10-10 12:01:55 -0400195#else
196 .features = DM_TARGET_PASSES_INTEGRITY,
197#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 .module = THIS_MODULE,
199 .ctr = linear_ctr,
200 .dtr = linear_dtr,
201 .map = linear_map,
202 .status = linear_status,
Christoph Hellwige56f81e2015-10-15 14:10:50 +0200203 .prepare_ioctl = linear_prepare_ioctl,
Mike Snitzeraf4874e2009-06-22 10:12:33 +0100204 .iterate_devices = linear_iterate_devices,
Dan Williams817bf402017-04-12 13:37:44 -0700205 .direct_access = linear_dax_direct_access,
Dan Williams7e026c82017-05-29 12:57:56 -0700206 .dax_copy_from_iter = linear_dax_copy_from_iter,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207};
208
209int __init dm_linear_init(void)
210{
211 int r = dm_register_target(&linear_target);
212
213 if (r < 0)
Alasdair G Kergon72d94862006-06-26 00:27:35 -0700214 DMERR("register failed %d", r);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
216 return r;
217}
218
219void dm_linear_exit(void)
220{
Mikulas Patocka10d3bd02009-01-06 03:04:58 +0000221 dm_unregister_target(&linear_target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}