| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2001-2003 Sistina Software (UK) Limited. |
| 3 | * |
| 4 | * This file is released under the GPL. |
| 5 | */ |
| 6 | |
| 7 | #include "dm.h" |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/init.h> |
| 11 | #include <linux/blkdev.h> |
| 12 | #include <linux/bio.h> |
| 13 | #include <linux/slab.h> |
| 14 | |
| 15 | /* |
| 16 | * Linear: maps a linear range of a device. |
| 17 | */ |
| 18 | struct linear_c { |
| 19 | struct dm_dev *dev; |
| 20 | sector_t start; |
| 21 | }; |
| 22 | |
| 23 | /* |
| 24 | * Construct a linear mapping: <dev_path> <offset> |
| 25 | */ |
| 26 | static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 27 | { |
| 28 | struct linear_c *lc; |
| 29 | |
| 30 | if (argc != 2) { |
| 31 | ti->error = "dm-linear: Invalid argument count"; |
| 32 | return -EINVAL; |
| 33 | } |
| 34 | |
| 35 | lc = kmalloc(sizeof(*lc), GFP_KERNEL); |
| 36 | if (lc == NULL) { |
| 37 | ti->error = "dm-linear: Cannot allocate linear context"; |
| 38 | return -ENOMEM; |
| 39 | } |
| 40 | |
| 41 | if (sscanf(argv[1], SECTOR_FORMAT, &lc->start) != 1) { |
| 42 | ti->error = "dm-linear: Invalid device sector"; |
| 43 | goto bad; |
| 44 | } |
| 45 | |
| 46 | if (dm_get_device(ti, argv[0], lc->start, ti->len, |
| 47 | dm_table_get_mode(ti->table), &lc->dev)) { |
| 48 | ti->error = "dm-linear: Device lookup failed"; |
| 49 | goto bad; |
| 50 | } |
| 51 | |
| 52 | ti->private = lc; |
| 53 | return 0; |
| 54 | |
| 55 | bad: |
| 56 | kfree(lc); |
| 57 | return -EINVAL; |
| 58 | } |
| 59 | |
| 60 | static void linear_dtr(struct dm_target *ti) |
| 61 | { |
| 62 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 63 | |
| 64 | dm_put_device(ti, lc->dev); |
| 65 | kfree(lc); |
| 66 | } |
| 67 | |
| 68 | static int linear_map(struct dm_target *ti, struct bio *bio, |
| 69 | union map_info *map_context) |
| 70 | { |
| 71 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 72 | |
| 73 | bio->bi_bdev = lc->dev->bdev; |
| 74 | bio->bi_sector = lc->start + (bio->bi_sector - ti->begin); |
| 75 | |
| 76 | return 1; |
| 77 | } |
| 78 | |
| 79 | static int linear_status(struct dm_target *ti, status_type_t type, |
| 80 | char *result, unsigned int maxlen) |
| 81 | { |
| 82 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 83 | |
| 84 | switch (type) { |
| 85 | case STATUSTYPE_INFO: |
| 86 | result[0] = '\0'; |
| 87 | break; |
| 88 | |
| 89 | case STATUSTYPE_TABLE: |
| 90 | snprintf(result, maxlen, "%s " SECTOR_FORMAT, lc->dev->name, |
| 91 | lc->start); |
| 92 | break; |
| 93 | } |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | static struct target_type linear_target = { |
| 98 | .name = "linear", |
| 99 | .version= {1, 0, 1}, |
| 100 | .module = THIS_MODULE, |
| 101 | .ctr = linear_ctr, |
| 102 | .dtr = linear_dtr, |
| 103 | .map = linear_map, |
| 104 | .status = linear_status, |
| 105 | }; |
| 106 | |
| 107 | int __init dm_linear_init(void) |
| 108 | { |
| 109 | int r = dm_register_target(&linear_target); |
| 110 | |
| 111 | if (r < 0) |
| 112 | DMERR("linear: register failed %d", r); |
| 113 | |
| 114 | return r; |
| 115 | } |
| 116 | |
| 117 | void dm_linear_exit(void) |
| 118 | { |
| 119 | int r = dm_unregister_target(&linear_target); |
| 120 | |
| 121 | if (r < 0) |
| 122 | DMERR("linear: unregister failed %d", r); |
| 123 | } |