Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
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
110 switch (type) {
111 case STATUSTYPE_INFO:
112 result[0] = '\0';
113 break;
114
115 case STATUSTYPE_TABLE:
116 snprintf(result, maxlen, "%s %llu", lc->dev->name,
117 (unsigned long long)lc->start);
118 break;
119 }
120}
121
122static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
123{
124 struct linear_c *lc = (struct linear_c *) ti->private;
125 struct dm_dev *dev = lc->dev;
126
127 *bdev = dev->bdev;
128
129 /*
130 * Only pass ioctls through if the device sizes match exactly.
131 */
132 if (lc->start ||
133 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
134 return 1;
135 return 0;
136}
137
138#ifdef CONFIG_BLK_DEV_ZONED
139static int linear_report_zones(struct dm_target *ti,
140 struct dm_report_zones_args *args, unsigned int nr_zones)
141{
142 struct linear_c *lc = ti->private;
143 sector_t sector = linear_map_sector(ti, args->next_sector);
144
145 args->start = lc->start;
146 return blkdev_report_zones(lc->dev->bdev, sector, nr_zones,
147 dm_report_zones_cb, args);
148}
149#else
150#define linear_report_zones NULL
151#endif
152
153static int linear_iterate_devices(struct dm_target *ti,
154 iterate_devices_callout_fn fn, void *data)
155{
156 struct linear_c *lc = ti->private;
157
158 return fn(ti, lc->dev, lc->start, ti->len, data);
159}
160
161#if IS_ENABLED(CONFIG_DAX_DRIVER)
162static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
163 long nr_pages, void **kaddr, pfn_t *pfn)
164{
165 long ret;
166 struct linear_c *lc = ti->private;
167 struct block_device *bdev = lc->dev->bdev;
168 struct dax_device *dax_dev = lc->dev->dax_dev;
169 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
170
171 dev_sector = linear_map_sector(ti, sector);
172 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
173 if (ret)
174 return ret;
175 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
176}
177
178static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
179 void *addr, size_t bytes, struct iov_iter *i)
180{
181 struct linear_c *lc = ti->private;
182 struct block_device *bdev = lc->dev->bdev;
183 struct dax_device *dax_dev = lc->dev->dax_dev;
184 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
185
186 dev_sector = linear_map_sector(ti, sector);
187 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
188 return 0;
189 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
190}
191
192static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
193 void *addr, size_t bytes, struct iov_iter *i)
194{
195 struct linear_c *lc = ti->private;
196 struct block_device *bdev = lc->dev->bdev;
197 struct dax_device *dax_dev = lc->dev->dax_dev;
198 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
199
200 dev_sector = linear_map_sector(ti, sector);
201 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
202 return 0;
203 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
204}
205
206static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
207 size_t nr_pages)
208{
209 int ret;
210 struct linear_c *lc = ti->private;
211 struct block_device *bdev = lc->dev->bdev;
212 struct dax_device *dax_dev = lc->dev->dax_dev;
213 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
214
215 dev_sector = linear_map_sector(ti, sector);
216 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages << PAGE_SHIFT, &pgoff);
217 if (ret)
218 return ret;
219 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
220}
221
222#else
223#define linear_dax_direct_access NULL
224#define linear_dax_copy_from_iter NULL
225#define linear_dax_copy_to_iter NULL
226#define linear_dax_zero_page_range NULL
227#endif
228
229static struct target_type linear_target = {
230 .name = "linear",
231 .version = {1, 4, 0},
232 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
233 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
234 .report_zones = linear_report_zones,
235 .module = THIS_MODULE,
236 .ctr = linear_ctr,
237 .dtr = linear_dtr,
238 .map = linear_map,
239 .status = linear_status,
240 .prepare_ioctl = linear_prepare_ioctl,
241 .iterate_devices = linear_iterate_devices,
242 .direct_access = linear_dax_direct_access,
243 .dax_copy_from_iter = linear_dax_copy_from_iter,
244 .dax_copy_to_iter = linear_dax_copy_to_iter,
245 .dax_zero_page_range = linear_dax_zero_page_range,
246};
247
248int __init dm_linear_init(void)
249{
250 int r = dm_register_target(&linear_target);
251
252 if (r < 0)
253 DMERR("register failed %d", r);
254
255 return r;
256}
257
258void dm_linear_exit(void)
259{
260 dm_unregister_target(&linear_target);
261}