1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2017 Intel Corporation. |
4 | * |
5 | * This file is released under the GPL. |
6 | */ |
7 | |
8 | #include "dm.h" |
9 | |
10 | #include <linux/module.h> |
11 | |
12 | struct unstripe_c { |
13 | struct dm_dev *dev; |
14 | sector_t physical_start; |
15 | |
16 | uint32_t stripes; |
17 | |
18 | uint32_t unstripe; |
19 | sector_t unstripe_width; |
20 | sector_t unstripe_offset; |
21 | |
22 | uint32_t chunk_size; |
23 | u8 chunk_shift; |
24 | }; |
25 | |
26 | #define DM_MSG_PREFIX "unstriped" |
27 | |
28 | static void cleanup_unstripe(struct unstripe_c *uc, struct dm_target *ti) |
29 | { |
30 | if (uc->dev) |
31 | dm_put_device(ti, d: uc->dev); |
32 | kfree(objp: uc); |
33 | } |
34 | |
35 | /* |
36 | * Contruct an unstriped mapping. |
37 | * <number of stripes> <chunk size> <stripe #> <dev_path> <offset> |
38 | */ |
39 | static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) |
40 | { |
41 | struct unstripe_c *uc; |
42 | sector_t tmp_len; |
43 | unsigned long long start; |
44 | char dummy; |
45 | |
46 | if (argc != 5) { |
47 | ti->error = "Invalid number of arguments" ; |
48 | return -EINVAL; |
49 | } |
50 | |
51 | uc = kzalloc(size: sizeof(*uc), GFP_KERNEL); |
52 | if (!uc) { |
53 | ti->error = "Memory allocation for unstriped context failed" ; |
54 | return -ENOMEM; |
55 | } |
56 | |
57 | if (kstrtouint(s: argv[0], base: 10, res: &uc->stripes) || !uc->stripes) { |
58 | ti->error = "Invalid stripe count" ; |
59 | goto err; |
60 | } |
61 | |
62 | if (kstrtouint(s: argv[1], base: 10, res: &uc->chunk_size) || !uc->chunk_size) { |
63 | ti->error = "Invalid chunk_size" ; |
64 | goto err; |
65 | } |
66 | |
67 | if (kstrtouint(s: argv[2], base: 10, res: &uc->unstripe)) { |
68 | ti->error = "Invalid stripe number" ; |
69 | goto err; |
70 | } |
71 | |
72 | if (uc->unstripe > uc->stripes && uc->stripes > 1) { |
73 | ti->error = "Please provide stripe between [0, # of stripes]" ; |
74 | goto err; |
75 | } |
76 | |
77 | if (dm_get_device(ti, path: argv[3], mode: dm_table_get_mode(t: ti->table), result: &uc->dev)) { |
78 | ti->error = "Couldn't get striped device" ; |
79 | goto err; |
80 | } |
81 | |
82 | if (sscanf(argv[4], "%llu%c" , &start, &dummy) != 1 || start != (sector_t)start) { |
83 | ti->error = "Invalid striped device offset" ; |
84 | goto err; |
85 | } |
86 | uc->physical_start = start; |
87 | |
88 | uc->unstripe_offset = uc->unstripe * uc->chunk_size; |
89 | uc->unstripe_width = (uc->stripes - 1) * uc->chunk_size; |
90 | uc->chunk_shift = is_power_of_2(n: uc->chunk_size) ? fls(x: uc->chunk_size) - 1 : 0; |
91 | |
92 | tmp_len = ti->len; |
93 | if (sector_div(tmp_len, uc->chunk_size)) { |
94 | ti->error = "Target length not divisible by chunk size" ; |
95 | goto err; |
96 | } |
97 | |
98 | if (dm_set_target_max_io_len(ti, len: uc->chunk_size)) { |
99 | ti->error = "Failed to set max io len" ; |
100 | goto err; |
101 | } |
102 | |
103 | ti->private = uc; |
104 | return 0; |
105 | err: |
106 | cleanup_unstripe(uc, ti); |
107 | return -EINVAL; |
108 | } |
109 | |
110 | static void unstripe_dtr(struct dm_target *ti) |
111 | { |
112 | struct unstripe_c *uc = ti->private; |
113 | |
114 | cleanup_unstripe(uc, ti); |
115 | } |
116 | |
117 | static sector_t map_to_core(struct dm_target *ti, struct bio *bio) |
118 | { |
119 | struct unstripe_c *uc = ti->private; |
120 | sector_t sector = bio->bi_iter.bi_sector; |
121 | sector_t tmp_sector = sector; |
122 | |
123 | /* Shift us up to the right "row" on the stripe */ |
124 | if (uc->chunk_shift) |
125 | tmp_sector >>= uc->chunk_shift; |
126 | else |
127 | sector_div(tmp_sector, uc->chunk_size); |
128 | |
129 | sector += uc->unstripe_width * tmp_sector; |
130 | |
131 | /* Account for what stripe we're operating on */ |
132 | return sector + uc->unstripe_offset; |
133 | } |
134 | |
135 | static int unstripe_map(struct dm_target *ti, struct bio *bio) |
136 | { |
137 | struct unstripe_c *uc = ti->private; |
138 | |
139 | bio_set_dev(bio, bdev: uc->dev->bdev); |
140 | bio->bi_iter.bi_sector = map_to_core(ti, bio) + uc->physical_start; |
141 | |
142 | return DM_MAPIO_REMAPPED; |
143 | } |
144 | |
145 | static void unstripe_status(struct dm_target *ti, status_type_t type, |
146 | unsigned int status_flags, char *result, unsigned int maxlen) |
147 | { |
148 | struct unstripe_c *uc = ti->private; |
149 | unsigned int sz = 0; |
150 | |
151 | switch (type) { |
152 | case STATUSTYPE_INFO: |
153 | break; |
154 | |
155 | case STATUSTYPE_TABLE: |
156 | DMEMIT("%d %llu %d %s %llu" , |
157 | uc->stripes, (unsigned long long)uc->chunk_size, uc->unstripe, |
158 | uc->dev->name, (unsigned long long)uc->physical_start); |
159 | break; |
160 | |
161 | case STATUSTYPE_IMA: |
162 | *result = '\0'; |
163 | break; |
164 | } |
165 | } |
166 | |
167 | static int unstripe_iterate_devices(struct dm_target *ti, |
168 | iterate_devices_callout_fn fn, void *data) |
169 | { |
170 | struct unstripe_c *uc = ti->private; |
171 | |
172 | return fn(ti, uc->dev, uc->physical_start, ti->len, data); |
173 | } |
174 | |
175 | static void unstripe_io_hints(struct dm_target *ti, |
176 | struct queue_limits *limits) |
177 | { |
178 | struct unstripe_c *uc = ti->private; |
179 | |
180 | limits->chunk_sectors = uc->chunk_size; |
181 | } |
182 | |
183 | static struct target_type unstripe_target = { |
184 | .name = "unstriped" , |
185 | .version = {1, 1, 0}, |
186 | .features = DM_TARGET_NOWAIT, |
187 | .module = THIS_MODULE, |
188 | .ctr = unstripe_ctr, |
189 | .dtr = unstripe_dtr, |
190 | .map = unstripe_map, |
191 | .status = unstripe_status, |
192 | .iterate_devices = unstripe_iterate_devices, |
193 | .io_hints = unstripe_io_hints, |
194 | }; |
195 | module_dm(unstripe); |
196 | |
197 | MODULE_DESCRIPTION(DM_NAME " unstriped target" ); |
198 | MODULE_ALIAS("dm-unstriped" ); |
199 | MODULE_AUTHOR("Scott Bauer <scott.bauer@intel.com>" ); |
200 | MODULE_LICENSE("GPL" ); |
201 | |