1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 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 */ 22 struct linear_c { 23 struct dm_dev *dev; 24 sector_t start; 25 }; 26 27 /* 28 * Construct a linear mapping: <dev_path> <offset> 29 */ 30 static 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->private = lc; 66 return 0; 67 68 bad: 69 kfree(lc); 70 return ret; 71 } 72 73 static void linear_dtr(struct dm_target *ti) 74 { 75 struct linear_c *lc = ti->private; 76 77 dm_put_device(ti, lc->dev); 78 kfree(lc); 79 } 80 81 static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) 82 { 83 struct linear_c *lc = ti->private; 84 85 return lc->start + dm_target_offset(ti, bi_sector); 86 } 87 88 static int linear_map(struct dm_target *ti, struct bio *bio) 89 { 90 struct linear_c *lc = ti->private; 91 92 bio_set_dev(bio, lc->dev->bdev); 93 bio->bi_iter.bi_sector = linear_map_sector(ti, bio->bi_iter.bi_sector); 94 95 return DM_MAPIO_REMAPPED; 96 } 97 98 static void linear_status(struct dm_target *ti, status_type_t type, 99 unsigned int status_flags, char *result, unsigned int maxlen) 100 { 101 struct linear_c *lc = ti->private; 102 size_t sz = 0; 103 104 switch (type) { 105 case STATUSTYPE_INFO: 106 result[0] = '\0'; 107 break; 108 109 case STATUSTYPE_TABLE: 110 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start); 111 break; 112 113 case STATUSTYPE_IMA: 114 DMEMIT_TARGET_NAME_VERSION(ti->type); 115 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name, 116 (unsigned long long)lc->start); 117 break; 118 } 119 } 120 121 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) 122 { 123 struct linear_c *lc = ti->private; 124 struct dm_dev *dev = lc->dev; 125 126 *bdev = dev->bdev; 127 128 /* 129 * Only pass ioctls through if the device sizes match exactly. 130 */ 131 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev)) 132 return 1; 133 return 0; 134 } 135 136 #ifdef CONFIG_BLK_DEV_ZONED 137 static int linear_report_zones(struct dm_target *ti, 138 struct dm_report_zones_args *args, unsigned int nr_zones) 139 { 140 struct linear_c *lc = ti->private; 141 142 return dm_report_zones(lc->dev->bdev, lc->start, 143 linear_map_sector(ti, args->next_sector), 144 args, nr_zones); 145 } 146 #else 147 #define linear_report_zones NULL 148 #endif 149 150 static int linear_iterate_devices(struct dm_target *ti, 151 iterate_devices_callout_fn fn, void *data) 152 { 153 struct linear_c *lc = ti->private; 154 155 return fn(ti, lc->dev, lc->start, ti->len, data); 156 } 157 158 #if IS_ENABLED(CONFIG_FS_DAX) 159 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff) 160 { 161 struct linear_c *lc = ti->private; 162 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT); 163 164 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT; 165 return lc->dev->dax_dev; 166 } 167 168 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 169 long nr_pages, enum dax_access_mode mode, void **kaddr, 170 pfn_t *pfn) 171 { 172 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 173 174 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn); 175 } 176 177 static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff, 178 size_t nr_pages) 179 { 180 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 181 182 return dax_zero_page_range(dax_dev, pgoff, nr_pages); 183 } 184 185 static size_t linear_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff, 186 void *addr, size_t bytes, struct iov_iter *i) 187 { 188 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 189 190 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i); 191 } 192 193 #else 194 #define linear_dax_direct_access NULL 195 #define linear_dax_zero_page_range NULL 196 #define linear_dax_recovery_write NULL 197 #endif 198 199 static struct target_type linear_target = { 200 .name = "linear", 201 .version = {1, 4, 0}, 202 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT | 203 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO, 204 .report_zones = linear_report_zones, 205 .module = THIS_MODULE, 206 .ctr = linear_ctr, 207 .dtr = linear_dtr, 208 .map = linear_map, 209 .status = linear_status, 210 .prepare_ioctl = linear_prepare_ioctl, 211 .iterate_devices = linear_iterate_devices, 212 .direct_access = linear_dax_direct_access, 213 .dax_zero_page_range = linear_dax_zero_page_range, 214 .dax_recovery_write = linear_dax_recovery_write, 215 }; 216 217 int __init dm_linear_init(void) 218 { 219 int r = dm_register_target(&linear_target); 220 221 if (r < 0) 222 DMERR("register failed %d", r); 223 224 return r; 225 } 226 227 void dm_linear_exit(void) 228 { 229 dm_unregister_target(&linear_target); 230 } 231