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->flush_bypasses_map = true; 66 ti->private = lc; 67 return 0; 68 69 bad: 70 kfree(lc); 71 return ret; 72 } 73 74 static 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 82 static 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 89 int 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 99 static 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 } 121 122 static 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_ZONED 138 static 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 #else 148 #define linear_report_zones NULL 149 #endif 150 151 static 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) 160 static 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 } 168 169 static 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 } 177 178 static 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 } 185 186 static 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 #else 195 #define linear_dax_direct_access NULL 196 #define linear_dax_zero_page_range NULL 197 #define linear_dax_recovery_write NULL 198 #endif 199 200 static 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 }; 217 218 int __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 } 227 228 void dm_linear_exit(void) 229 { 230 dm_unregister_target(&linear_target); 231 } 232