/* * Copyright (C) 2001-2003 Sistina Software (UK) Limited. * * This file is released under the GPL. */ #include "dm.h" #include <linux/module.h> #include <linux/init.h> #include <linux/blkdev.h> #include <linux/bio.h> #include <linux/slab.h> /* * Linear: maps a linear range of a device. */ struct linear_c { struct dm_dev *dev; sector_t start; }; /* * Construct a linear mapping: <dev_path> <offset> */ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct linear_c *lc; if (argc != 2) { ti->error = "dm-linear: Invalid argument count"; return -EINVAL; } lc = kmalloc(sizeof(*lc), GFP_KERNEL); if (lc == NULL) { ti->error = "dm-linear: Cannot allocate linear context"; return -ENOMEM; } if (sscanf(argv[1], SECTOR_FORMAT, &lc->start) != 1) { ti->error = "dm-linear: Invalid device sector"; goto bad; } if (dm_get_device(ti, argv[0], lc->start, ti->len, dm_table_get_mode(ti->table), &lc->dev)) { ti->error = "dm-linear: Device lookup failed"; goto bad; } ti->private = lc; return 0; bad: kfree(lc); return -EINVAL; } static void linear_dtr(struct dm_target *ti) { struct linear_c *lc = (struct linear_c *) ti->private; dm_put_device(ti, lc->dev); kfree(lc); } static int linear_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { struct linear_c *lc = (struct linear_c *) ti->private; bio->bi_bdev = lc->dev->bdev; bio->bi_sector = lc->start + (bio->bi_sector - ti->begin); return 1; } static int linear_status(struct dm_target *ti, status_type_t type, char *result, unsigned int maxlen) { struct linear_c *lc = (struct linear_c *) ti->private; switch (type) { case STATUSTYPE_INFO: result[0] = '\0'; break; case STATUSTYPE_TABLE: snprintf(result, maxlen, "%s " SECTOR_FORMAT, lc->dev->name, lc->start); break; } return 0; } static struct target_type linear_target = { .name = "linear", .version= {1, 0, 1}, .module = THIS_MODULE, .ctr = linear_ctr, .dtr = linear_dtr, .map = linear_map, .status = linear_status, }; int __init dm_linear_init(void) { int r = dm_register_target(&linear_target); if (r < 0) DMERR("linear: register failed %d", r); return r; } void dm_linear_exit(void) { int r = dm_unregister_target(&linear_target); if (r < 0) DMERR("linear: unregister failed %d", r); }