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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.4 *5 * This file is released under the GPL.6 */7 8#include "dm.h"9#include <linux/module.h>10#include <linux/init.h>11#include <linux/blkdev.h>12#include <linux/bio.h>13#include <linux/dax.h>14#include <linux/slab.h>15#include <linux/device-mapper.h>16 17#define DM_MSG_PREFIX "linear"18 19/*20 * Linear: maps a linear range of a device.21 */22struct linear_c {23 struct dm_dev *dev;24 sector_t start;25};26 27/*28 * Construct a linear mapping: <dev_path> <offset>29 */30static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)31{32 struct linear_c *lc;33 unsigned long long tmp;34 char dummy;35 int ret;36 37 if (argc != 2) {38 ti->error = "Invalid argument count";39 return -EINVAL;40 }41 42 lc = kmalloc(sizeof(*lc), GFP_KERNEL);43 if (lc == NULL) {44 ti->error = "Cannot allocate linear context";45 return -ENOMEM;46 }47 48 ret = -EINVAL;49 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {50 ti->error = "Invalid device sector";51 goto bad;52 }53 lc->start = tmp;54 55 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);56 if (ret) {57 ti->error = "Device lookup failed";58 goto bad;59 }60 61 ti->num_flush_bios = 1;62 ti->num_discard_bios = 1;63 ti->num_secure_erase_bios = 1;64 ti->num_write_zeroes_bios = 1;65 ti->flush_bypasses_map = true;66 ti->private = lc;67 return 0;68 69bad:70 kfree(lc);71 return ret;72}73 74static void linear_dtr(struct dm_target *ti)75{76 struct linear_c *lc = ti->private;77 78 dm_put_device(ti, lc->dev);79 kfree(lc);80}81 82static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)83{84 struct linear_c *lc = ti->private;85 86 return lc->start + dm_target_offset(ti, bi_sector);87}88 89int linear_map(struct dm_target *ti, struct bio *bio)90{91 struct linear_c *lc = ti->private;92 93 bio_set_dev(bio, lc->dev->bdev);94 bio->bi_iter.bi_sector = linear_map_sector(ti, bio->bi_iter.bi_sector);95 96 return DM_MAPIO_REMAPPED;97}98 99static void linear_status(struct dm_target *ti, status_type_t type,100 unsigned int status_flags, char *result, unsigned int maxlen)101{102 struct linear_c *lc = ti->private;103 size_t sz = 0;104 105 switch (type) {106 case STATUSTYPE_INFO:107 result[0] = '\0';108 break;109 110 case STATUSTYPE_TABLE:111 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start);112 break;113 114 case STATUSTYPE_IMA:115 DMEMIT_TARGET_NAME_VERSION(ti->type);116 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name,117 (unsigned long long)lc->start);118 break;119 }120}121 122static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)123{124 struct linear_c *lc = ti->private;125 struct dm_dev *dev = lc->dev;126 127 *bdev = dev->bdev;128 129 /*130 * Only pass ioctls through if the device sizes match exactly.131 */132 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev))133 return 1;134 return 0;135}136 137#ifdef CONFIG_BLK_DEV_ZONED138static int linear_report_zones(struct dm_target *ti,139 struct dm_report_zones_args *args, unsigned int nr_zones)140{141 struct linear_c *lc = ti->private;142 143 return dm_report_zones(lc->dev->bdev, lc->start,144 linear_map_sector(ti, args->next_sector),145 args, nr_zones);146}147#else148#define linear_report_zones NULL149#endif150 151static int linear_iterate_devices(struct dm_target *ti,152 iterate_devices_callout_fn fn, void *data)153{154 struct linear_c *lc = ti->private;155 156 return fn(ti, lc->dev, lc->start, ti->len, data);157}158 159#if IS_ENABLED(CONFIG_FS_DAX)160static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)161{162 struct linear_c *lc = ti->private;163 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);164 165 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;166 return lc->dev->dax_dev;167}168 169static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,170 long nr_pages, enum dax_access_mode mode, void **kaddr,171 pfn_t *pfn)172{173 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);174 175 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);176}177 178static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,179 size_t nr_pages)180{181 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);182 183 return dax_zero_page_range(dax_dev, pgoff, nr_pages);184}185 186static size_t linear_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,187 void *addr, size_t bytes, struct iov_iter *i)188{189 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);190 191 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);192}193 194#else195#define linear_dax_direct_access NULL196#define linear_dax_zero_page_range NULL197#define linear_dax_recovery_write NULL198#endif199 200static struct target_type linear_target = {201 .name = "linear",202 .version = {1, 4, 0},203 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |204 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,205 .report_zones = linear_report_zones,206 .module = THIS_MODULE,207 .ctr = linear_ctr,208 .dtr = linear_dtr,209 .map = linear_map,210 .status = linear_status,211 .prepare_ioctl = linear_prepare_ioctl,212 .iterate_devices = linear_iterate_devices,213 .direct_access = linear_dax_direct_access,214 .dax_zero_page_range = linear_dax_zero_page_range,215 .dax_recovery_write = linear_dax_recovery_write,216};217 218int __init dm_linear_init(void)219{220 int r = dm_register_target(&linear_target);221 222 if (r < 0)223 DMERR("register failed %d", r);224 225 return r;226}227 228void dm_linear_exit(void)229{230 dm_unregister_target(&linear_target);231}232