tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm.h"
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/blkdev.h>
11#include <linux/bio.h>
12#include <linux/dax.h>
13#include <linux/slab.h>
14#include <linux/device-mapper.h>
15
16#define DM_MSG_PREFIX "linear"
17
18/*
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;
32 unsigned long long tmp;
33 char dummy;
34 int ret;
35
36 if (argc != 2) {
37 ti->error = "Invalid argument count";
38 return -EINVAL;
39 }
40
41 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
42 if (lc == NULL) {
43 ti->error = "Cannot allocate linear context";
44 return -ENOMEM;
45 }
46
47 ret = -EINVAL;
48 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
49 ti->error = "Invalid device sector";
50 goto bad;
51 }
52 lc->start = tmp;
53
54 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
55 if (ret) {
56 ti->error = "Device lookup failed";
57 goto bad;
58 }
59
60 ti->num_flush_bios = 1;
61 ti->num_discard_bios = 1;
62 ti->num_secure_erase_bios = 1;
63 ti->num_write_same_bios = 1;
64 ti->num_write_zeroes_bios = 1;
65 ti->private = lc;
66 return 0;
67
68 bad:
69 kfree(lc);
70 return ret;
71}
72
73static void linear_dtr(struct dm_target *ti)
74{
75 struct linear_c *lc = (struct linear_c *) ti->private;
76
77 dm_put_device(ti, lc->dev);
78 kfree(lc);
79}
80
81static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
82{
83 struct linear_c *lc = ti->private;
84
85 return lc->start + dm_target_offset(ti, bi_sector);
86}
87
88static void linear_map_bio(struct dm_target *ti, struct bio *bio)
89{
90 struct linear_c *lc = ti->private;
91
92 bio_set_dev(bio, lc->dev->bdev);
93 if (bio_sectors(bio) || op_is_zone_mgmt(bio_op(bio)))
94 bio->bi_iter.bi_sector =
95 linear_map_sector(ti, bio->bi_iter.bi_sector);
96}
97
98static int linear_map(struct dm_target *ti, struct bio *bio)
99{
100 linear_map_bio(ti, bio);
101
102 return DM_MAPIO_REMAPPED;
103}
104
105static void linear_status(struct dm_target *ti, status_type_t type,
106 unsigned status_flags, char *result, unsigned maxlen)
107{
108 struct linear_c *lc = (struct linear_c *) ti->private;
109 size_t sz = 0;
110
111 switch (type) {
112 case STATUSTYPE_INFO:
113 result[0] = '\0';
114 break;
115
116 case STATUSTYPE_TABLE:
117 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start);
118 break;
119
120 case STATUSTYPE_IMA:
121 DMEMIT_TARGET_NAME_VERSION(ti->type);
122 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name,
123 (unsigned long long)lc->start);
124 break;
125 }
126}
127
128static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
129{
130 struct linear_c *lc = (struct linear_c *) ti->private;
131 struct dm_dev *dev = lc->dev;
132
133 *bdev = dev->bdev;
134
135 /*
136 * Only pass ioctls through if the device sizes match exactly.
137 */
138 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev))
139 return 1;
140 return 0;
141}
142
143#ifdef CONFIG_BLK_DEV_ZONED
144static int linear_report_zones(struct dm_target *ti,
145 struct dm_report_zones_args *args, unsigned int nr_zones)
146{
147 struct linear_c *lc = ti->private;
148
149 return dm_report_zones(lc->dev->bdev, lc->start,
150 linear_map_sector(ti, args->next_sector),
151 args, nr_zones);
152}
153#else
154#define linear_report_zones NULL
155#endif
156
157static int linear_iterate_devices(struct dm_target *ti,
158 iterate_devices_callout_fn fn, void *data)
159{
160 struct linear_c *lc = ti->private;
161
162 return fn(ti, lc->dev, lc->start, ti->len, data);
163}
164
165#if IS_ENABLED(CONFIG_FS_DAX)
166static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
167{
168 struct linear_c *lc = ti->private;
169 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);
170
171 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;
172 return lc->dev->dax_dev;
173}
174
175static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
176 long nr_pages, void **kaddr, pfn_t *pfn)
177{
178 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
179
180 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
181}
182
183static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
184 size_t nr_pages)
185{
186 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
187
188 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
189}
190
191#else
192#define linear_dax_direct_access NULL
193#define linear_dax_zero_page_range NULL
194#endif
195
196static struct target_type linear_target = {
197 .name = "linear",
198 .version = {1, 4, 0},
199 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
200 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
201 .report_zones = linear_report_zones,
202 .module = THIS_MODULE,
203 .ctr = linear_ctr,
204 .dtr = linear_dtr,
205 .map = linear_map,
206 .status = linear_status,
207 .prepare_ioctl = linear_prepare_ioctl,
208 .iterate_devices = linear_iterate_devices,
209 .direct_access = linear_dax_direct_access,
210 .dax_zero_page_range = linear_dax_zero_page_range,
211};
212
213int __init dm_linear_init(void)
214{
215 int r = dm_register_target(&linear_target);
216
217 if (r < 0)
218 DMERR("register failed %d", r);
219
220 return r;
221}
222
223void dm_linear_exit(void)
224{
225 dm_unregister_target(&linear_target);
226}