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_write_same_bios = 1;
71 static void linear_dtr(struct dm_target *ti)
73 struct linear_c *lc = (struct linear_c *) ti->private;
75 dm_put_device(ti, lc->dev);
79 static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
81 struct linear_c *lc = ti->private;
83 return lc->start + dm_target_offset(ti, bi_sector);
86 static void linear_map_bio(struct dm_target *ti, struct bio *bio)
88 struct linear_c *lc = ti->private;
90 bio->bi_bdev = lc->dev->bdev;
92 bio->bi_iter.bi_sector =
93 linear_map_sector(ti, bio->bi_iter.bi_sector);
96 static int linear_map(struct dm_target *ti, struct bio *bio)
98 linear_map_bio(ti, bio);
100 return DM_MAPIO_REMAPPED;
103 static void linear_status(struct dm_target *ti, status_type_t type,
104 unsigned status_flags, char *result, unsigned maxlen)
106 struct linear_c *lc = (struct linear_c *) ti->private;
109 case STATUSTYPE_INFO:
113 case STATUSTYPE_TABLE:
114 snprintf(result, maxlen, "%s %llu", lc->dev->name,
115 (unsigned long long)lc->start);
120 static int linear_prepare_ioctl(struct dm_target *ti,
121 struct block_device **bdev, fmode_t *mode)
123 struct linear_c *lc = (struct linear_c *) ti->private;
124 struct dm_dev *dev = lc->dev;
129 * Only pass ioctls through if the device sizes match exactly.
132 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
137 static int linear_iterate_devices(struct dm_target *ti,
138 iterate_devices_callout_fn fn, void *data)
140 struct linear_c *lc = ti->private;
142 return fn(ti, lc->dev, lc->start, ti->len, data);
145 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
146 long nr_pages, void **kaddr, pfn_t *pfn)
149 struct linear_c *lc = ti->private;
150 struct block_device *bdev = lc->dev->bdev;
151 struct dax_device *dax_dev = lc->dev->dax_dev;
152 sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
154 dev_sector = linear_map_sector(ti, sector);
155 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
158 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
161 static struct target_type linear_target = {
163 .version = {1, 3, 0},
164 .module = THIS_MODULE,
168 .status = linear_status,
169 .prepare_ioctl = linear_prepare_ioctl,
170 .iterate_devices = linear_iterate_devices,
171 .direct_access = linear_dax_direct_access,
174 int __init dm_linear_init(void)
176 int r = dm_register_target(&linear_target);
179 DMERR("register failed %d", r);
184 void dm_linear_exit(void)
186 dm_unregister_target(&linear_target);