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; |
31998ef1 | 32 | char dummy; |
1da177e4 LT |
33 | |
34 | if (argc != 2) { | |
72d94861 | 35 | ti->error = "Invalid argument count"; |
1da177e4 LT |
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 | ||
31998ef1 | 45 | if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) { |
1da177e4 LT |
46 | ti->error = "dm-linear: Invalid device sector"; |
47 | goto bad; | |
48 | } | |
4ee218cd | 49 | lc->start = tmp; |
1da177e4 | 50 | |
8215d6ec | 51 | if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev)) { |
1da177e4 LT |
52 | ti->error = "dm-linear: Device lookup failed"; |
53 | goto bad; | |
54 | } | |
55 | ||
55a62eef AK |
56 | ti->num_flush_bios = 1; |
57 | ti->num_discard_bios = 1; | |
58 | ti->num_write_same_bios = 1; | |
1da177e4 LT |
59 | ti->private = lc; |
60 | return 0; | |
61 | ||
62 | bad: | |
63 | kfree(lc); | |
64 | return -EINVAL; | |
65 | } | |
66 | ||
67 | static 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 | ||
7bc3447b | 75 | static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) |
1da177e4 | 76 | { |
7bc3447b MB |
77 | struct linear_c *lc = ti->private; |
78 | ||
b441a262 | 79 | return lc->start + dm_target_offset(ti, bi_sector); |
7bc3447b MB |
80 | } |
81 | ||
82 | static void linear_map_bio(struct dm_target *ti, struct bio *bio) | |
83 | { | |
84 | struct linear_c *lc = ti->private; | |
1da177e4 LT |
85 | |
86 | bio->bi_bdev = lc->dev->bdev; | |
433bcac5 | 87 | if (bio_sectors(bio)) |
4f024f37 KO |
88 | bio->bi_iter.bi_sector = |
89 | linear_map_sector(ti, bio->bi_iter.bi_sector); | |
7bc3447b MB |
90 | } |
91 | ||
7de3ee57 | 92 | static int linear_map(struct dm_target *ti, struct bio *bio) |
7bc3447b MB |
93 | { |
94 | linear_map_bio(ti, bio); | |
1da177e4 | 95 | |
d2a7ad29 | 96 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
97 | } |
98 | ||
fd7c092e MP |
99 | static void linear_status(struct dm_target *ti, status_type_t type, |
100 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
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: | |
4ee218cd AM |
110 | snprintf(result, maxlen, "%s %llu", lc->dev->name, |
111 | (unsigned long long)lc->start); | |
1da177e4 LT |
112 | break; |
113 | } | |
1da177e4 LT |
114 | } |
115 | ||
647b3d00 | 116 | static int linear_ioctl(struct dm_target *ti, unsigned int cmd, |
ab17ffa4 MB |
117 | unsigned long arg) |
118 | { | |
119 | struct linear_c *lc = (struct linear_c *) ti->private; | |
ec8013be PB |
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); | |
ab17ffa4 MB |
131 | } |
132 | ||
7bc3447b MB |
133 | static 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 | ||
af4874e0 MS |
148 | static 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 | ||
5dea271b | 153 | return fn(ti, lc->dev, lc->start, ti->len, data); |
af4874e0 MS |
154 | } |
155 | ||
1da177e4 LT |
156 | static struct target_type linear_target = { |
157 | .name = "linear", | |
fd7c092e | 158 | .version = {1, 2, 1}, |
1da177e4 LT |
159 | .module = THIS_MODULE, |
160 | .ctr = linear_ctr, | |
161 | .dtr = linear_dtr, | |
162 | .map = linear_map, | |
163 | .status = linear_status, | |
ab17ffa4 | 164 | .ioctl = linear_ioctl, |
7bc3447b | 165 | .merge = linear_merge, |
af4874e0 | 166 | .iterate_devices = linear_iterate_devices, |
1da177e4 LT |
167 | }; |
168 | ||
169 | int __init dm_linear_init(void) | |
170 | { | |
171 | int r = dm_register_target(&linear_target); | |
172 | ||
173 | if (r < 0) | |
72d94861 | 174 | DMERR("register failed %d", r); |
1da177e4 LT |
175 | |
176 | return r; | |
177 | } | |
178 | ||
179 | void dm_linear_exit(void) | |
180 | { | |
10d3bd09 | 181 | dm_unregister_target(&linear_target); |
1da177e4 | 182 | } |