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1// SPDX-License-Identifier: GPL-2.0-only2/*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, uc->dev);32 kfree(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(sizeof(*uc), GFP_KERNEL);52 if (!uc) {53 ti->error = "Memory allocation for unstriped context failed";54 return -ENOMEM;55 }56 57 if (kstrtouint(argv[0], 10, &uc->stripes) || !uc->stripes) {58 ti->error = "Invalid stripe count";59 goto err;60 }61 62 if (kstrtouint(argv[1], 10, &uc->chunk_size) || !uc->chunk_size) {63 ti->error = "Invalid chunk_size";64 goto err;65 }66 67 if (kstrtouint(argv[2], 10, &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, argv[3], dm_table_get_mode(ti->table), &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 = (sector_t)uc->unstripe * uc->chunk_size;89 uc->unstripe_width = (sector_t)(uc->stripes - 1) * uc->chunk_size;90 uc->chunk_shift = is_power_of_2(uc->chunk_size) ? fls(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, 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 else127 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, 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