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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#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/blkdev.h>
11#include <linux/bio.h>
12#include <linux/slab.h>
13#include <linux/device-mapper.h>
14
15#define DM_MSG_PREFIX "linear"
16
17/*
18 * Linear: maps a linear range of a device.
19 */
20struct linear_c {
21 struct dm_dev *dev;
22 sector_t start;
23};
24
25/*
26 * Construct a linear mapping: <dev_path> <offset>
27 */
28static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
29{
30 struct linear_c *lc;
31 unsigned long long tmp;
32 char dummy;
33
34 if (argc != 2) {
35 ti->error = "Invalid argument count";
36 return -EINVAL;
37 }
38
39 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
40 if (lc == NULL) {
41 ti->error = "dm-linear: Cannot allocate linear context";
42 return -ENOMEM;
43 }
44
45 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
46 ti->error = "dm-linear: Invalid device sector";
47 goto bad;
48 }
49 lc->start = tmp;
50
51 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev)) {
52 ti->error = "dm-linear: Device lookup failed";
53 goto bad;
54 }
55
56 ti->num_flush_requests = 1;
57 ti->num_discard_requests = 1;
58 ti->private = lc;
59 return 0;
60
61 bad:
62 kfree(lc);
63 return -EINVAL;
64}
65
66static void linear_dtr(struct dm_target *ti)
67{
68 struct linear_c *lc = (struct linear_c *) ti->private;
69
70 dm_put_device(ti, lc->dev);
71 kfree(lc);
72}
73
74static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
75{
76 struct linear_c *lc = ti->private;
77
78 return lc->start + dm_target_offset(ti, bi_sector);
79}
80
81static void linear_map_bio(struct dm_target *ti, struct bio *bio)
82{
83 struct linear_c *lc = ti->private;
84
85 bio->bi_bdev = lc->dev->bdev;
86 if (bio_sectors(bio))
87 bio->bi_sector = linear_map_sector(ti, bio->bi_sector);
88}
89
90static int linear_map(struct dm_target *ti, struct bio *bio,
91 union map_info *map_context)
92{
93 linear_map_bio(ti, bio);
94
95 return DM_MAPIO_REMAPPED;
96}
97
98static int linear_status(struct dm_target *ti, status_type_t type,
99 char *result, unsigned int maxlen)
100{
101 struct linear_c *lc = (struct linear_c *) ti->private;
102
103 switch (type) {
104 case STATUSTYPE_INFO:
105 result[0] = '\0';
106 break;
107
108 case STATUSTYPE_TABLE:
109 snprintf(result, maxlen, "%s %llu", lc->dev->name,
110 (unsigned long long)lc->start);
111 break;
112 }
113 return 0;
114}
115
116static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
117 unsigned long arg)
118{
119 struct linear_c *lc = (struct linear_c *) ti->private;
120 struct dm_dev *dev = lc->dev;
121 int r = 0;
122
123 /*
124 * Only pass ioctls through if the device sizes match exactly.
125 */
126 if (lc->start ||
127 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
128 r = scsi_verify_blk_ioctl(NULL, cmd);
129
130 return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
131}
132
133static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
134 struct bio_vec *biovec, int max_size)
135{
136 struct linear_c *lc = ti->private;
137 struct request_queue *q = bdev_get_queue(lc->dev->bdev);
138
139 if (!q->merge_bvec_fn)
140 return max_size;
141
142 bvm->bi_bdev = lc->dev->bdev;
143 bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
144
145 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
146}
147
148static int linear_iterate_devices(struct dm_target *ti,
149 iterate_devices_callout_fn fn, void *data)
150{
151 struct linear_c *lc = ti->private;
152
153 return fn(ti, lc->dev, lc->start, ti->len, data);
154}
155
156static struct target_type linear_target = {
157 .name = "linear",
158 .version = {1, 1, 0},
159 .module = THIS_MODULE,
160 .ctr = linear_ctr,
161 .dtr = linear_dtr,
162 .map = linear_map,
163 .status = linear_status,
164 .ioctl = linear_ioctl,
165 .merge = linear_merge,
166 .iterate_devices = linear_iterate_devices,
167};
168
169int __init dm_linear_init(void)
170{
171 int r = dm_register_target(&linear_target);
172
173 if (r < 0)
174 DMERR("register failed %d", r);
175
176 return r;
177}
178
179void dm_linear_exit(void)
180{
181 dm_unregister_target(&linear_target);
182}
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#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/blkdev.h>
11#include <linux/bio.h>
12#include <linux/slab.h>
13#include <linux/device-mapper.h>
14
15#define DM_MSG_PREFIX "linear"
16
17/*
18 * Linear: maps a linear range of a device.
19 */
20struct linear_c {
21 struct dm_dev *dev;
22 sector_t start;
23};
24
25/*
26 * Construct a linear mapping: <dev_path> <offset>
27 */
28static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
29{
30 struct linear_c *lc;
31 unsigned long long tmp;
32 char dummy;
33
34 if (argc != 2) {
35 ti->error = "Invalid argument count";
36 return -EINVAL;
37 }
38
39 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
40 if (lc == NULL) {
41 ti->error = "dm-linear: Cannot allocate linear context";
42 return -ENOMEM;
43 }
44
45 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
46 ti->error = "dm-linear: Invalid device sector";
47 goto bad;
48 }
49 lc->start = tmp;
50
51 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev)) {
52 ti->error = "dm-linear: Device lookup failed";
53 goto bad;
54 }
55
56 ti->num_flush_bios = 1;
57 ti->num_discard_bios = 1;
58 ti->num_write_same_bios = 1;
59 ti->private = lc;
60 return 0;
61
62 bad:
63 kfree(lc);
64 return -EINVAL;
65}
66
67static void linear_dtr(struct dm_target *ti)
68{
69 struct linear_c *lc = (struct linear_c *) ti->private;
70
71 dm_put_device(ti, lc->dev);
72 kfree(lc);
73}
74
75static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
76{
77 struct linear_c *lc = ti->private;
78
79 return lc->start + dm_target_offset(ti, bi_sector);
80}
81
82static void linear_map_bio(struct dm_target *ti, struct bio *bio)
83{
84 struct linear_c *lc = ti->private;
85
86 bio->bi_bdev = lc->dev->bdev;
87 if (bio_sectors(bio))
88 bio->bi_iter.bi_sector =
89 linear_map_sector(ti, bio->bi_iter.bi_sector);
90}
91
92static int linear_map(struct dm_target *ti, struct bio *bio)
93{
94 linear_map_bio(ti, bio);
95
96 return DM_MAPIO_REMAPPED;
97}
98
99static void linear_status(struct dm_target *ti, status_type_t type,
100 unsigned status_flags, char *result, unsigned maxlen)
101{
102 struct linear_c *lc = (struct linear_c *) ti->private;
103
104 switch (type) {
105 case STATUSTYPE_INFO:
106 result[0] = '\0';
107 break;
108
109 case STATUSTYPE_TABLE:
110 snprintf(result, maxlen, "%s %llu", lc->dev->name,
111 (unsigned long long)lc->start);
112 break;
113 }
114}
115
116static int linear_ioctl(struct dm_target *ti, unsigned int cmd,
117 unsigned long arg)
118{
119 struct linear_c *lc = (struct linear_c *) ti->private;
120 struct dm_dev *dev = lc->dev;
121 int r = 0;
122
123 /*
124 * Only pass ioctls through if the device sizes match exactly.
125 */
126 if (lc->start ||
127 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
128 r = scsi_verify_blk_ioctl(NULL, cmd);
129
130 return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
131}
132
133static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
134 struct bio_vec *biovec, int max_size)
135{
136 struct linear_c *lc = ti->private;
137 struct request_queue *q = bdev_get_queue(lc->dev->bdev);
138
139 if (!q->merge_bvec_fn)
140 return max_size;
141
142 bvm->bi_bdev = lc->dev->bdev;
143 bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector);
144
145 return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
146}
147
148static int linear_iterate_devices(struct dm_target *ti,
149 iterate_devices_callout_fn fn, void *data)
150{
151 struct linear_c *lc = ti->private;
152
153 return fn(ti, lc->dev, lc->start, ti->len, data);
154}
155
156static struct target_type linear_target = {
157 .name = "linear",
158 .version = {1, 2, 1},
159 .module = THIS_MODULE,
160 .ctr = linear_ctr,
161 .dtr = linear_dtr,
162 .map = linear_map,
163 .status = linear_status,
164 .ioctl = linear_ioctl,
165 .merge = linear_merge,
166 .iterate_devices = linear_iterate_devices,
167};
168
169int __init dm_linear_init(void)
170{
171 int r = dm_register_target(&linear_target);
172
173 if (r < 0)
174 DMERR("register failed %d", r);
175
176 return r;
177}
178
179void dm_linear_exit(void)
180{
181 dm_unregister_target(&linear_target);
182}