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_zeroes_bios = 1;
72 static void linear_dtr(struct dm_target *ti)
74 struct linear_c *lc = (struct linear_c *) ti->private;
76 dm_put_device(ti, lc->dev);
80 static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
82 struct linear_c *lc = ti->private;
84 return lc->start + dm_target_offset(ti, bi_sector);
87 static void linear_map_bio(struct dm_target *ti, struct bio *bio)
89 struct linear_c *lc = ti->private;
91 bio_set_dev(bio, lc->dev->bdev);
92 if (bio_sectors(bio) || op_is_zone_mgmt(bio_op(bio)))
93 bio->bi_iter.bi_sector =
94 linear_map_sector(ti, bio->bi_iter.bi_sector);
97 static int linear_map(struct dm_target *ti, struct bio *bio)
99 linear_map_bio(ti, bio);
101 return DM_MAPIO_REMAPPED;
104 static void linear_status(struct dm_target *ti, status_type_t type,
105 unsigned status_flags, char *result, unsigned maxlen)
107 struct linear_c *lc = (struct linear_c *) ti->private;
111 case STATUSTYPE_INFO:
115 case STATUSTYPE_TABLE:
116 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start);
120 DMEMIT_TARGET_NAME_VERSION(ti->type);
121 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name,
122 (unsigned long long)lc->start);
127 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
129 struct linear_c *lc = (struct linear_c *) ti->private;
130 struct dm_dev *dev = lc->dev;
135 * Only pass ioctls through if the device sizes match exactly.
137 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev))
142 #ifdef CONFIG_BLK_DEV_ZONED
143 static int linear_report_zones(struct dm_target *ti,
144 struct dm_report_zones_args *args, unsigned int nr_zones)
146 struct linear_c *lc = ti->private;
148 return dm_report_zones(lc->dev->bdev, lc->start,
149 linear_map_sector(ti, args->next_sector),
153 #define linear_report_zones NULL
156 static int linear_iterate_devices(struct dm_target *ti,
157 iterate_devices_callout_fn fn, void *data)
159 struct linear_c *lc = ti->private;
161 return fn(ti, lc->dev, lc->start, ti->len, data);
164 #if IS_ENABLED(CONFIG_FS_DAX)
165 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
167 struct linear_c *lc = ti->private;
168 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);
170 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;
171 return lc->dev->dax_dev;
174 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
175 long nr_pages, void **kaddr, pfn_t *pfn)
177 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
179 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
182 static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
185 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
187 return dax_zero_page_range(dax_dev, pgoff, nr_pages);
191 #define linear_dax_direct_access NULL
192 #define linear_dax_zero_page_range NULL
195 static struct target_type linear_target = {
197 .version = {1, 4, 0},
198 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
199 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
200 .report_zones = linear_report_zones,
201 .module = THIS_MODULE,
205 .status = linear_status,
206 .prepare_ioctl = linear_prepare_ioctl,
207 .iterate_devices = linear_iterate_devices,
208 .direct_access = linear_dax_direct_access,
209 .dax_zero_page_range = linear_dax_zero_page_range,
212 int __init dm_linear_init(void)
214 int r = dm_register_target(&linear_target);
217 DMERR("register failed %d", r);
222 void dm_linear_exit(void)
224 dm_unregister_target(&linear_target);