summaryrefslogtreecommitdiffstats
path: root/drivers/md/dm-linear.c
blob: fc9c4272c10dbac2b5a76ab59379bbf1e00f26e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
/*
 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
 *
 * This file is released under the GPL.
 */

#include "dm.h"
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "linear"

/*
 * Linear: maps a linear range of a device.
 */
struct linear_c {
	struct dm_dev *dev;
	sector_t start;
};

/*
 * Construct a linear mapping: <dev_path> <offset>
 */
static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
	struct linear_c *lc;
	unsigned long long tmp;
	char dummy;
	int ret;

	if (argc != 2) {
		ti->error = "Invalid argument count";
		return -EINVAL;
	}

	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
	if (lc == NULL) {
		ti->error = "Cannot allocate linear context";
		return -ENOMEM;
	}

	ret = -EINVAL;
	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
		ti->error = "Invalid device sector";
		goto bad;
	}
	lc->start = tmp;

	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
	if (ret) {
		ti->error = "Device lookup failed";
		goto bad;
	}

	ti->num_flush_bios = 1;
	ti->num_discard_bios = 1;
	ti->num_secure_erase_bios = 1;
	ti->num_write_same_bios = 1;
	ti->num_write_zeroes_bios = 1;
	ti->private = lc;
	return 0;

      bad:
	kfree(lc);
	return ret;
}

static void linear_dtr(struct dm_target *ti)
{
	struct linear_c *lc = (struct linear_c *) ti->private;

	dm_put_device(ti, lc->dev);
	kfree(lc);
}

static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
{
	struct linear_c *lc = ti->private;

	return lc->start + dm_target_offset(ti, bi_sector);
}

static void linear_map_bio(struct dm_target *ti, struct bio *bio)
{
	struct linear_c *lc = ti->private;

	bio_set_dev(bio, lc->dev->bdev);
	if (bio_sectors(bio) || op_is_zone_mgmt(bio_op(bio)))
		bio->bi_iter.bi_sector =
			linear_map_sector(ti, bio->bi_iter.bi_sector);
}

static int linear_map(struct dm_target *ti, struct bio *bio)
{
	linear_map_bio(ti, bio);

	return DM_MAPIO_REMAPPED;
}

static void linear_status(struct dm_target *ti, status_type_t type,
			  unsigned status_flags, char *result, unsigned maxlen)
{
	struct linear_c *lc = (struct linear_c *) ti->private;

	switch (type) {
	case STATUSTYPE_INFO:
		result[0] = '\0';
		break;

	case STATUSTYPE_TABLE:
		snprintf(result, maxlen, "%s %llu", lc->dev->name,
				(unsigned long long)lc->start);
		break;
	}
}

static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
{
	struct linear_c *lc = (struct linear_c *) ti->private;
	struct dm_dev *dev = lc->dev;

	*bdev = dev->bdev;

	/*
	 * Only pass ioctls through if the device sizes match exactly.
	 */
	if (lc->start ||
	    ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
		return 1;
	return 0;
}

#ifdef CONFIG_BLK_DEV_ZONED
static int linear_report_zones(struct dm_target *ti,
		struct dm_report_zones_args *args, unsigned int nr_zones)
{
	struct linear_c *lc = ti->private;
	sector_t sector = linear_map_sector(ti, args->next_sector);

	args->start = lc->start;
	return blkdev_report_zones(lc->dev->bdev, sector, nr_zones,
				   dm_report_zones_cb, args);
}
#endif

static int linear_iterate_devices(struct dm_target *ti,
				  iterate_devices_callout_fn fn, void *data)
{
	struct linear_c *lc = ti->private;

	return fn(ti, lc->dev, lc->start, ti->len, data);
}

#if IS_ENABLED(CONFIG_DAX_DRIVER)
static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
		long nr_pages, void **kaddr, pfn_t *pfn)
{
	long ret;
	struct linear_c *lc = ti->private;
	struct block_device *bdev = lc->dev->bdev;
	struct dax_device *dax_dev = lc->dev->dax_dev;
	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;

	dev_sector = linear_map_sector(ti, sector);
	ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
	if (ret)
		return ret;
	return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
}

static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
		void *addr, size_t bytes, struct iov_iter *i)
{
	struct linear_c *lc = ti->private;
	struct block_device *bdev = lc->dev->bdev;
	struct dax_device *dax_dev = lc->dev->dax_dev;
	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;

	dev_sector = linear_map_sector(ti, sector);
	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
		return 0;
	return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}

static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
		void *addr, size_t bytes, struct iov_iter *i)
{
	struct linear_c *lc = ti->private;
	struct block_device *bdev = lc->dev->bdev;
	struct dax_device *dax_dev = lc->dev->dax_dev;
	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;

	dev_sector = linear_map_sector(ti, sector);
	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
		return 0;
	return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
}

static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
				      size_t nr_pages)
{
	int ret;
	struct linear_c *lc = ti->private;
	struct block_device *bdev = lc->dev->bdev;
	struct dax_device *dax_dev = lc->dev->dax_dev;
	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;

	dev_sector = linear_map_sector(ti, sector);
	ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages << PAGE_SHIFT, &pgoff);
	if (ret)
		return ret;
	return dax_zero_page_range(dax_dev, pgoff, nr_pages);
}

#else
#define linear_dax_direct_access NULL
#define linear_dax_copy_from_iter NULL
#define linear_dax_copy_to_iter NULL
#define linear_dax_zero_page_range NULL
#endif

static struct target_type linear_target = {
	.name   = "linear",
	.version = {1, 4, 0},
#ifdef CONFIG_BLK_DEV_ZONED
	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
		    DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
	.report_zones = linear_report_zones,
#else
	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
		    DM_TARGET_PASSES_CRYPTO,
#endif
	.module = THIS_MODULE,
	.ctr    = linear_ctr,
	.dtr    = linear_dtr,
	.map    = linear_map,
	.status = linear_status,
	.prepare_ioctl = linear_prepare_ioctl,
	.iterate_devices = linear_iterate_devices,
	.direct_access = linear_dax_direct_access,
	.dax_copy_from_iter = linear_dax_copy_from_iter,
	.dax_copy_to_iter = linear_dax_copy_to_iter,
	.dax_zero_page_range = linear_dax_zero_page_range,
};

int __init dm_linear_init(void)
{
	int r = dm_register_target(&linear_target);

	if (r < 0)
		DMERR("register failed %d", r);

	return r;
}

void dm_linear_exit(void)
{
	dm_unregister_target(&linear_target);
}