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) {
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) || bio_op(bio) == REQ_OP_ZONE_RESET)
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 int linear_end_io(struct dm_target *ti, struct bio *bio,
108 struct linear_c *lc = ti->private;
110 if (!*error && bio_op(bio) == REQ_OP_ZONE_REPORT)
111 dm_remap_zone_report(ti, bio, lc->start);
113 return DM_ENDIO_DONE;
116 static void linear_status(struct dm_target *ti, status_type_t type,
117 unsigned status_flags, char *result, unsigned maxlen)
119 struct linear_c *lc = (struct linear_c *) ti->private;
122 case STATUSTYPE_INFO:
126 case STATUSTYPE_TABLE:
127 snprintf(result, maxlen, "%s %llu", lc->dev->name,
128 (unsigned long long)lc->start);
133 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
135 struct linear_c *lc = (struct linear_c *) ti->private;
136 struct dm_dev *dev = lc->dev;
141 * Only pass ioctls through if the device sizes match exactly.
144 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
149 static int linear_iterate_devices(struct dm_target *ti,
150 iterate_devices_callout_fn fn, void *data)
152 struct linear_c *lc = ti->private;
154 return fn(ti, lc->dev, lc->start, ti->len, data);
157 #if IS_ENABLED(CONFIG_DAX_DRIVER)
158 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
159 long nr_pages, void **kaddr, pfn_t *pfn)
162 struct linear_c *lc = ti->private;
163 struct block_device *bdev = lc->dev->bdev;
164 struct dax_device *dax_dev = lc->dev->dax_dev;
165 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
167 dev_sector = linear_map_sector(ti, sector);
168 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
171 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
174 static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
175 void *addr, size_t bytes, struct iov_iter *i)
177 struct linear_c *lc = ti->private;
178 struct block_device *bdev = lc->dev->bdev;
179 struct dax_device *dax_dev = lc->dev->dax_dev;
180 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
182 dev_sector = linear_map_sector(ti, sector);
183 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
185 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
188 static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
189 void *addr, size_t bytes, struct iov_iter *i)
191 struct linear_c *lc = ti->private;
192 struct block_device *bdev = lc->dev->bdev;
193 struct dax_device *dax_dev = lc->dev->dax_dev;
194 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
196 dev_sector = linear_map_sector(ti, sector);
197 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
199 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
203 #define linear_dax_direct_access NULL
204 #define linear_dax_copy_from_iter NULL
205 #define linear_dax_copy_to_iter NULL
208 static struct target_type linear_target = {
210 .version = {1, 4, 0},
211 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
212 .module = THIS_MODULE,
216 .end_io = linear_end_io,
217 .status = linear_status,
218 .prepare_ioctl = linear_prepare_ioctl,
219 .iterate_devices = linear_iterate_devices,
220 .direct_access = linear_dax_direct_access,
221 .dax_copy_from_iter = linear_dax_copy_from_iter,
222 .dax_copy_to_iter = linear_dax_copy_to_iter,
225 int __init dm_linear_init(void)
227 int r = dm_register_target(&linear_target);
230 DMERR("register failed %d", r);
235 void dm_linear_exit(void)
237 dm_unregister_target(&linear_target);