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> | |
817bf402 | 12 | #include <linux/dax.h> |
1da177e4 | 13 | #include <linux/slab.h> |
586e80e6 | 14 | #include <linux/device-mapper.h> |
1da177e4 | 15 | |
72d94861 AK |
16 | #define DM_MSG_PREFIX "linear" |
17 | ||
1da177e4 LT |
18 | /* |
19 | * Linear: maps a linear range of a device. | |
20 | */ | |
21 | struct linear_c { | |
22 | struct dm_dev *dev; | |
23 | sector_t start; | |
24 | }; | |
25 | ||
26 | /* | |
27 | * Construct a linear mapping: <dev_path> <offset> | |
28 | */ | |
29 | static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) | |
30 | { | |
31 | struct linear_c *lc; | |
4ee218cd | 32 | unsigned long long tmp; |
31998ef1 | 33 | char dummy; |
e80d1c80 | 34 | int ret; |
1da177e4 LT |
35 | |
36 | if (argc != 2) { | |
72d94861 | 37 | ti->error = "Invalid argument count"; |
1da177e4 LT |
38 | return -EINVAL; |
39 | } | |
40 | ||
41 | lc = kmalloc(sizeof(*lc), GFP_KERNEL); | |
42 | if (lc == NULL) { | |
00272c85 | 43 | ti->error = "Cannot allocate linear context"; |
1da177e4 LT |
44 | return -ENOMEM; |
45 | } | |
46 | ||
e80d1c80 | 47 | ret = -EINVAL; |
31998ef1 | 48 | if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) { |
00272c85 | 49 | ti->error = "Invalid device sector"; |
1da177e4 LT |
50 | goto bad; |
51 | } | |
4ee218cd | 52 | lc->start = tmp; |
1da177e4 | 53 | |
e80d1c80 VG |
54 | ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev); |
55 | if (ret) { | |
00272c85 | 56 | ti->error = "Device lookup failed"; |
1da177e4 LT |
57 | goto bad; |
58 | } | |
59 | ||
55a62eef AK |
60 | ti->num_flush_bios = 1; |
61 | ti->num_discard_bios = 1; | |
62 | ti->num_write_same_bios = 1; | |
ac62d620 | 63 | ti->num_write_zeroes_bios = 1; |
1da177e4 LT |
64 | ti->private = lc; |
65 | return 0; | |
66 | ||
67 | bad: | |
68 | kfree(lc); | |
e80d1c80 | 69 | return ret; |
1da177e4 LT |
70 | } |
71 | ||
72 | static void linear_dtr(struct dm_target *ti) | |
73 | { | |
74 | struct linear_c *lc = (struct linear_c *) ti->private; | |
75 | ||
76 | dm_put_device(ti, lc->dev); | |
77 | kfree(lc); | |
78 | } | |
79 | ||
7bc3447b | 80 | static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) |
1da177e4 | 81 | { |
7bc3447b MB |
82 | struct linear_c *lc = ti->private; |
83 | ||
b441a262 | 84 | return lc->start + dm_target_offset(ti, bi_sector); |
7bc3447b MB |
85 | } |
86 | ||
87 | static void linear_map_bio(struct dm_target *ti, struct bio *bio) | |
88 | { | |
89 | struct linear_c *lc = ti->private; | |
1da177e4 LT |
90 | |
91 | bio->bi_bdev = lc->dev->bdev; | |
433bcac5 | 92 | if (bio_sectors(bio)) |
4f024f37 KO |
93 | bio->bi_iter.bi_sector = |
94 | linear_map_sector(ti, bio->bi_iter.bi_sector); | |
7bc3447b MB |
95 | } |
96 | ||
7de3ee57 | 97 | static int linear_map(struct dm_target *ti, struct bio *bio) |
7bc3447b MB |
98 | { |
99 | linear_map_bio(ti, bio); | |
1da177e4 | 100 | |
d2a7ad29 | 101 | return DM_MAPIO_REMAPPED; |
1da177e4 LT |
102 | } |
103 | ||
fd7c092e MP |
104 | static void linear_status(struct dm_target *ti, status_type_t type, |
105 | unsigned status_flags, char *result, unsigned maxlen) | |
1da177e4 LT |
106 | { |
107 | struct linear_c *lc = (struct linear_c *) ti->private; | |
108 | ||
109 | switch (type) { | |
110 | case STATUSTYPE_INFO: | |
111 | result[0] = '\0'; | |
112 | break; | |
113 | ||
114 | case STATUSTYPE_TABLE: | |
4ee218cd AM |
115 | snprintf(result, maxlen, "%s %llu", lc->dev->name, |
116 | (unsigned long long)lc->start); | |
1da177e4 LT |
117 | break; |
118 | } | |
1da177e4 LT |
119 | } |
120 | ||
e56f81e0 CH |
121 | static int linear_prepare_ioctl(struct dm_target *ti, |
122 | struct block_device **bdev, fmode_t *mode) | |
ab17ffa4 MB |
123 | { |
124 | struct linear_c *lc = (struct linear_c *) ti->private; | |
ec8013be | 125 | struct dm_dev *dev = lc->dev; |
e56f81e0 CH |
126 | |
127 | *bdev = dev->bdev; | |
ec8013be PB |
128 | |
129 | /* | |
130 | * Only pass ioctls through if the device sizes match exactly. | |
131 | */ | |
132 | if (lc->start || | |
133 | ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
e56f81e0 CH |
134 | return 1; |
135 | return 0; | |
ab17ffa4 MB |
136 | } |
137 | ||
af4874e0 MS |
138 | static int linear_iterate_devices(struct dm_target *ti, |
139 | iterate_devices_callout_fn fn, void *data) | |
140 | { | |
141 | struct linear_c *lc = ti->private; | |
142 | ||
5dea271b | 143 | return fn(ti, lc->dev, lc->start, ti->len, data); |
af4874e0 MS |
144 | } |
145 | ||
817bf402 DW |
146 | static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, |
147 | long nr_pages, void **kaddr, pfn_t *pfn) | |
84b22f83 | 148 | { |
817bf402 | 149 | long ret; |
84b22f83 TK |
150 | struct linear_c *lc = ti->private; |
151 | struct block_device *bdev = lc->dev->bdev; | |
817bf402 DW |
152 | struct dax_device *dax_dev = lc->dev->dax_dev; |
153 | sector_t dev_sector, sector = pgoff * PAGE_SECTORS; | |
154 | ||
155 | dev_sector = linear_map_sector(ti, sector); | |
156 | ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); | |
157 | if (ret) | |
158 | return ret; | |
159 | return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); | |
84b22f83 TK |
160 | } |
161 | ||
1da177e4 LT |
162 | static struct target_type linear_target = { |
163 | .name = "linear", | |
84b22f83 | 164 | .version = {1, 3, 0}, |
e2460f2a | 165 | .features = DM_TARGET_PASSES_INTEGRITY, |
1da177e4 LT |
166 | .module = THIS_MODULE, |
167 | .ctr = linear_ctr, | |
168 | .dtr = linear_dtr, | |
169 | .map = linear_map, | |
170 | .status = linear_status, | |
e56f81e0 | 171 | .prepare_ioctl = linear_prepare_ioctl, |
af4874e0 | 172 | .iterate_devices = linear_iterate_devices, |
817bf402 | 173 | .direct_access = linear_dax_direct_access, |
1da177e4 LT |
174 | }; |
175 | ||
176 | int __init dm_linear_init(void) | |
177 | { | |
178 | int r = dm_register_target(&linear_target); | |
179 | ||
180 | if (r < 0) | |
72d94861 | 181 | DMERR("register failed %d", r); |
1da177e4 LT |
182 | |
183 | return r; | |
184 | } | |
185 | ||
186 | void dm_linear_exit(void) | |
187 | { | |
10d3bd09 | 188 | dm_unregister_target(&linear_target); |
1da177e4 | 189 | } |