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 | |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 15 | #define DM_MSG_PREFIX "linear" |
| 16 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | /* |
| 18 | * Linear: maps a linear range of a device. |
| 19 | */ |
| 20 | struct linear_c { |
| 21 | struct dm_dev *dev; |
| 22 | sector_t start; |
| 23 | }; |
| 24 | |
| 25 | /* |
| 26 | * Construct a linear mapping: <dev_path> <offset> |
| 27 | */ |
| 28 | static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
| 29 | { |
| 30 | struct linear_c *lc; |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 31 | unsigned long long tmp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
| 33 | if (argc != 2) { |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 34 | ti->error = "Invalid argument count"; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | return -EINVAL; |
| 36 | } |
| 37 | |
| 38 | lc = kmalloc(sizeof(*lc), GFP_KERNEL); |
| 39 | if (lc == NULL) { |
| 40 | ti->error = "dm-linear: Cannot allocate linear context"; |
| 41 | return -ENOMEM; |
| 42 | } |
| 43 | |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 44 | if (sscanf(argv[1], "%llu", &tmp) != 1) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | ti->error = "dm-linear: Invalid device sector"; |
| 46 | goto bad; |
| 47 | } |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 48 | lc->start = tmp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | |
| 50 | if (dm_get_device(ti, argv[0], lc->start, ti->len, |
| 51 | dm_table_get_mode(ti->table), &lc->dev)) { |
| 52 | ti->error = "dm-linear: Device lookup failed"; |
| 53 | goto bad; |
| 54 | } |
| 55 | |
| 56 | ti->private = lc; |
| 57 | return 0; |
| 58 | |
| 59 | bad: |
| 60 | kfree(lc); |
| 61 | return -EINVAL; |
| 62 | } |
| 63 | |
| 64 | static void linear_dtr(struct dm_target *ti) |
| 65 | { |
| 66 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 67 | |
| 68 | dm_put_device(ti, lc->dev); |
| 69 | kfree(lc); |
| 70 | } |
| 71 | |
Milan Broz | 7bc3447 | 2008-07-21 12:00:38 +0100 | [diff] [blame] | 72 | static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) |
| 73 | { |
| 74 | struct linear_c *lc = ti->private; |
| 75 | |
| 76 | return lc->start + (bi_sector - ti->begin); |
| 77 | } |
| 78 | |
| 79 | static void linear_map_bio(struct dm_target *ti, struct bio *bio) |
| 80 | { |
| 81 | struct linear_c *lc = ti->private; |
| 82 | |
| 83 | bio->bi_bdev = lc->dev->bdev; |
| 84 | bio->bi_sector = linear_map_sector(ti, bio->bi_sector); |
| 85 | } |
| 86 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | static int linear_map(struct dm_target *ti, struct bio *bio, |
| 88 | union map_info *map_context) |
| 89 | { |
Milan Broz | 7bc3447 | 2008-07-21 12:00:38 +0100 | [diff] [blame] | 90 | linear_map_bio(ti, bio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
Kiyoshi Ueda | d2a7ad2 | 2006-12-08 02:41:06 -0800 | [diff] [blame] | 92 | return DM_MAPIO_REMAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | } |
| 94 | |
| 95 | static int linear_status(struct dm_target *ti, status_type_t type, |
| 96 | char *result, unsigned int maxlen) |
| 97 | { |
| 98 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 99 | |
| 100 | switch (type) { |
| 101 | case STATUSTYPE_INFO: |
| 102 | result[0] = '\0'; |
| 103 | break; |
| 104 | |
| 105 | case STATUSTYPE_TABLE: |
Andrew Morton | 4ee218c | 2006-03-27 01:17:48 -0800 | [diff] [blame] | 106 | snprintf(result, maxlen, "%s %llu", lc->dev->name, |
| 107 | (unsigned long long)lc->start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | break; |
| 109 | } |
| 110 | return 0; |
| 111 | } |
| 112 | |
Milan Broz | ab17ffa | 2006-10-03 01:15:18 -0700 | [diff] [blame] | 113 | static int linear_ioctl(struct dm_target *ti, struct inode *inode, |
| 114 | struct file *filp, unsigned int cmd, |
| 115 | unsigned long arg) |
| 116 | { |
| 117 | struct linear_c *lc = (struct linear_c *) ti->private; |
| 118 | struct block_device *bdev = lc->dev->bdev; |
Milan Broz | e90dae1 | 2006-10-03 01:15:22 -0700 | [diff] [blame] | 119 | struct file fake_file = {}; |
| 120 | struct dentry fake_dentry = {}; |
Milan Broz | ab17ffa | 2006-10-03 01:15:18 -0700 | [diff] [blame] | 121 | |
Milan Broz | e90dae1 | 2006-10-03 01:15:22 -0700 | [diff] [blame] | 122 | fake_file.f_mode = lc->dev->mode; |
Josef Sipek | c649bb9 | 2006-12-08 02:37:19 -0800 | [diff] [blame] | 123 | fake_file.f_path.dentry = &fake_dentry; |
Milan Broz | e90dae1 | 2006-10-03 01:15:22 -0700 | [diff] [blame] | 124 | fake_dentry.d_inode = bdev->bd_inode; |
| 125 | |
| 126 | return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg); |
Milan Broz | ab17ffa | 2006-10-03 01:15:18 -0700 | [diff] [blame] | 127 | } |
| 128 | |
Milan Broz | 7bc3447 | 2008-07-21 12:00:38 +0100 | [diff] [blame] | 129 | static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
| 130 | struct bio_vec *biovec, int max_size) |
| 131 | { |
| 132 | struct linear_c *lc = ti->private; |
| 133 | struct request_queue *q = bdev_get_queue(lc->dev->bdev); |
| 134 | |
| 135 | if (!q->merge_bvec_fn) |
| 136 | return max_size; |
| 137 | |
| 138 | bvm->bi_bdev = lc->dev->bdev; |
| 139 | bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector); |
| 140 | |
| 141 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); |
| 142 | } |
| 143 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | static struct target_type linear_target = { |
| 145 | .name = "linear", |
Milan Broz | 7bc3447 | 2008-07-21 12:00:38 +0100 | [diff] [blame] | 146 | .version= {1, 0, 3}, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | .module = THIS_MODULE, |
| 148 | .ctr = linear_ctr, |
| 149 | .dtr = linear_dtr, |
| 150 | .map = linear_map, |
| 151 | .status = linear_status, |
Milan Broz | ab17ffa | 2006-10-03 01:15:18 -0700 | [diff] [blame] | 152 | .ioctl = linear_ioctl, |
Milan Broz | 7bc3447 | 2008-07-21 12:00:38 +0100 | [diff] [blame] | 153 | .merge = linear_merge, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | }; |
| 155 | |
| 156 | int __init dm_linear_init(void) |
| 157 | { |
| 158 | int r = dm_register_target(&linear_target); |
| 159 | |
| 160 | if (r < 0) |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 161 | DMERR("register failed %d", r); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | |
| 163 | return r; |
| 164 | } |
| 165 | |
| 166 | void dm_linear_exit(void) |
| 167 | { |
| 168 | int r = dm_unregister_target(&linear_target); |
| 169 | |
| 170 | if (r < 0) |
Alasdair G Kergon | 72d9486 | 2006-06-26 00:27:35 -0700 | [diff] [blame] | 171 | DMERR("unregister failed %d", r); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | } |