2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
4 * This file is released under the GPL.
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>
16 #define DM_MSG_PREFIX "linear"
19 * Linear: maps a linear range of a device.
27 * Construct a linear mapping: <dev_path> <offset>
29 static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
32 unsigned long long tmp;
37 ti->error = "Invalid argument count";
41 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
43 ti->error = "Cannot allocate linear context";
48 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
49 ti->error = "Invalid device sector";
54 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
56 ti->error = "Device lookup failed";
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;
73 static void linear_dtr(struct dm_target *ti)
75 struct linear_c *lc = (struct linear_c *) ti->private;
77 dm_put_device(ti, lc->dev);
81 static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
83 struct linear_c *lc = ti->private;
85 return lc->start + dm_target_offset(ti, bi_sector);
88 static void linear_map_bio(struct dm_target *ti, struct bio *bio)
90 struct linear_c *lc = ti->private;
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);
98 static int linear_map(struct dm_target *ti, struct bio *bio)
100 linear_map_bio(ti, bio);
102 return DM_MAPIO_REMAPPED;
105 static void linear_status(struct dm_target *ti, status_type_t type,
106 unsigned status_flags, char *result, unsigned maxlen)
108 struct linear_c *lc = (struct linear_c *) ti->private;
112 case STATUSTYPE_INFO:
116 case STATUSTYPE_TABLE:
117 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start);
121 DMEMIT_TARGET_NAME_VERSION(ti->type);
122 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name,
123 (unsigned long long)lc->start);
128 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
130 struct linear_c *lc = (struct linear_c *) ti->private;
131 struct dm_dev *dev = lc->dev;
136 * Only pass ioctls through if the device sizes match exactly.
138 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev))
143 #ifdef CONFIG_BLK_DEV_ZONED
144 static int linear_report_zones(struct dm_target *ti,
145 struct dm_report_zones_args *args, unsigned int nr_zones)
147 struct linear_c *lc = ti->private;
149 return dm_report_zones(lc->dev->bdev, lc->start,
150 linear_map_sector(ti, args->next_sector),
154 #define linear_report_zones NULL
157 static int linear_iterate_devices(struct dm_target *ti,
158 iterate_devices_callout_fn fn, void *data)
160 struct linear_c *lc = ti->private;
162 return fn(ti, lc->dev, lc->start, ti->len, data);
165 #if IS_ENABLED(CONFIG_FS_DAX)
166 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
168 struct linear_c *lc = ti->private;
169 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);
171 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;
172 return lc->dev->dax_dev;
175 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
176 long nr_pages, void **kaddr, pfn_t *pfn)
178 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
180 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
183 static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
186 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
188 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
192 #define linear_dax_direct_access NULL
193 #define linear_dax_zero_page_range NULL
196 static struct target_type linear_target = {
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,
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,
213 int __init dm_linear_init(void)
215 int r = dm_register_target(&linear_target);
218 DMERR("register failed %d", r);
223 void dm_linear_exit(void)
225 dm_unregister_target(&linear_target);