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 } 124