Commit | Line | Data |
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1da177e4 LT |
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" | |
1da177e4 LT |
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> | |
586e80e6 | 13 | #include <linux/device-mapper.h> |
1da177e4 | 14 | |
72d94861 AK |
15 | #define DM_MSG_PREFIX "linear" |
16 | ||
1da177e4 LT |
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; | |
4ee218cd | 31 | unsigned long long tmp; |
1da177e4 LT |
32 | |
33 | if (argc != 2) { | |
72d94861 | 34 | ti->error = "Invalid argument count"; |
1da177e4 LT |
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 | ||
4ee218cd | 44 | if (sscanf(argv[1], "%llu", &tmp) != 1) { |
1da177e4 LT |
45 | ti->error = "dm-linear: Invalid device sector"; |
46 | goto bad; | |
47 | } | |
4ee218cd | 48 | lc->start = tmp; |
1da177e4 LT |
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 | ||
7bc3447b | 72 | static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) |
1da177e4 | 73 | { |
7bc3447b MB |
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; | |
1da177e4 LT |
82 | |
83 | bio->bi_bdev = lc->dev->bdev; | |
7bc3447b MB |
84 | bio->bi_sector = linear_map_sector(ti, bio->bi_sector); |
85 | } | |
86 | ||
87 | static int linear_map(struct dm_target *ti, struct bio *bio, | |
88 | union map_info *map_context) | |
89 | { | |
90 | linear_map_bio(ti, bio); | |
1da177e4 | 91 | |
d2a7ad29 | 92 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
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: | |
4ee218cd AM |
106 | snprintf(result, maxlen, "%s %llu", lc->dev->name, |
107 | (unsigned long long)lc->start); | |
1da177e4 LT |
108 | break; |
109 | } | |
110 | return 0; | |
111 | } | |
112 | ||
647b3d00 | 113 | static int linear_ioctl(struct dm_target *ti, unsigned int cmd, |
ab17ffa4 MB |
114 | unsigned long arg) |
115 | { | |
116 | struct linear_c *lc = (struct linear_c *) ti->private; | |
633a08b8 | 117 | return __blkdev_driver_ioctl(lc->dev->bdev, lc->dev->mode, cmd, arg); |
ab17ffa4 MB |
118 | } |
119 | ||
7bc3447b MB |
120 | static int linear_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
121 | struct bio_vec *biovec, int max_size) | |
122 | { | |
123 | struct linear_c *lc = ti->private; | |
124 | struct request_queue *q = bdev_get_queue(lc->dev->bdev); | |
125 | ||
126 | if (!q->merge_bvec_fn) | |
127 | return max_size; | |
128 | ||
129 | bvm->bi_bdev = lc->dev->bdev; | |
130 | bvm->bi_sector = linear_map_sector(ti, bvm->bi_sector); | |
131 | ||
132 | return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); | |
133 | } | |
134 | ||
1da177e4 LT |
135 | static struct target_type linear_target = { |
136 | .name = "linear", | |
7bc3447b | 137 | .version= {1, 0, 3}, |
1da177e4 LT |
138 | .module = THIS_MODULE, |
139 | .ctr = linear_ctr, | |
140 | .dtr = linear_dtr, | |
141 | .map = linear_map, | |
142 | .status = linear_status, | |
ab17ffa4 | 143 | .ioctl = linear_ioctl, |
7bc3447b | 144 | .merge = linear_merge, |
ab4c1424 | 145 | .features = DM_TARGET_SUPPORTS_BARRIERS, |
1da177e4 LT |
146 | }; |
147 | ||
148 | int __init dm_linear_init(void) | |
149 | { | |
150 | int r = dm_register_target(&linear_target); | |
151 | ||
152 | if (r < 0) | |
72d94861 | 153 | DMERR("register failed %d", r); |
1da177e4 LT |
154 | |
155 | return r; | |
156 | } | |
157 | ||
158 | void dm_linear_exit(void) | |
159 | { | |
10d3bd09 | 160 | dm_unregister_target(&linear_target); |
1da177e4 | 161 | } |