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 unsigned long long tmp; 30 31 if (argc != 2) { 32 ti->error = "dm-linear: Invalid argument count"; 33 return -EINVAL; 34 } 35 36 lc = kmalloc(sizeof(*lc), GFP_KERNEL); 37 if (lc == NULL) { 38 ti->error = "dm-linear: Cannot allocate linear context"; 39 return -ENOMEM; 40 } 41 42 if (sscanf(argv[1], "%llu", &tmp) != 1) { 43 ti->error = "dm-linear: Invalid device sector"; 44 goto bad; 45 } 46 lc->start = tmp; 47 48 if (dm_get_device(ti, argv[0], lc->start, ti->len, 49 dm_table_get_mode(ti->table), &lc->dev)) { 50 ti->error = "dm-linear: Device lookup failed"; 51 goto bad; 52 } 53 54 ti->private = lc; 55 return 0; 56 57 bad: 58 kfree(lc); 59 return -EINVAL; 60 } 61 62 static void linear_dtr(struct dm_target *ti) 63 { 64 struct linear_c *lc = (struct linear_c *) ti->private; 65 66 dm_put_device(ti, lc->dev); 67 kfree(lc); 68 } 69 70 static int linear_map(struct dm_target *ti, struct bio *bio, 71 union map_info *map_context) 72 { 73 struct linear_c *lc = (struct linear_c *) ti->private; 74 75 bio->bi_bdev = lc->dev->bdev; 76 bio->bi_sector = lc->start + (bio->bi_sector - ti->begin); 77 78 return 1; 79 } 80 81 static int linear_status(struct dm_target *ti, status_type_t type, 82 char *result, unsigned int maxlen) 83 { 84 struct linear_c *lc = (struct linear_c *) ti->private; 85 86 switch (type) { 87 case STATUSTYPE_INFO: 88 result[0] = '\0'; 89 break; 90 91 case STATUSTYPE_TABLE: 92 snprintf(result, maxlen, "%s %llu", lc->dev->name, 93 (unsigned long long)lc->start); 94 break; 95 } 96 return 0; 97 } 98 99 static struct target_type linear_target = { 100 .name = "linear", 101 .version= {1, 0, 1}, 102 .module = THIS_MODULE, 103 .ctr = linear_ctr, 104 .dtr = linear_dtr, 105 .map = linear_map, 106 .status = linear_status, 107 }; 108 109 int __init dm_linear_init(void) 110 { 111 int r = dm_register_target(&linear_target); 112 113 if (r < 0) 114 DMERR("linear: register failed %d", r); 115 116 return r; 117 } 118 119 void dm_linear_exit(void) 120 { 121 int r = dm_unregister_target(&linear_target); 122 123 if (r < 0) 124 DMERR("linear: unregister failed %d", r); 125 } 126