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
12struct 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
28static 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 */
39static 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;
105err:
106 cleanup_unstripe(uc, ti);
107 return -EINVAL;
108}
109
110static void unstripe_dtr(struct dm_target *ti)
111{
112 struct unstripe_c *uc = ti->private;
113
114 cleanup_unstripe(uc, ti);
115}
116
117static 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
135static 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
145static 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
167static 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
175static 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
183static 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};
195module_dm(unstripe);
196
197MODULE_DESCRIPTION(DM_NAME " unstriped target");
198MODULE_ALIAS("dm-unstriped");
199MODULE_AUTHOR("Scott Bauer <scott.bauer@intel.com>");
200MODULE_LICENSE("GPL");
201

source code of linux/drivers/md/dm-unstripe.c