1 /* 2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited. 3 * 4 * This file is released under the GPL. 5 */ 6 7 #include "dm.h" 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/blkdev.h> 11 #include <linux/bio.h> 12 #include <linux/dax.h> 13 #include <linux/slab.h> 14 #include <linux/device-mapper.h> 15 16 #define DM_MSG_PREFIX "linear" 17 18 /* 19 * Linear: maps a linear range of a device. 20 */ 21 struct linear_c { 22 struct dm_dev *dev; 23 sector_t start; 24 }; 25 26 /* 27 * Construct a linear mapping: <dev_path> <offset> 28 */ 29 static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) 30 { 31 struct linear_c *lc; 32 unsigned long long tmp; 33 char dummy; 34 int ret; 35 36 if (argc != 2) { 37 ti->error = "Invalid argument count"; 38 return -EINVAL; 39 } 40 41 lc = kmalloc(sizeof(*lc), GFP_KERNEL); 42 if (lc == NULL) { 43 ti->error = "Cannot allocate linear context"; 44 return -ENOMEM; 45 } 46 47 ret = -EINVAL; 48 if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) { 49 ti->error = "Invalid device sector"; 50 goto bad; 51 } 52 lc->start = tmp; 53 54 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev); 55 if (ret) { 56 ti->error = "Device lookup failed"; 57 goto bad; 58 } 59 60 ti->num_flush_bios = 1; 61 ti->num_discard_bios = 1; 62 ti->num_secure_erase_bios = 1; 63 ti->num_write_zeroes_bios = 1; 64 ti->private = lc; 65 return 0; 66 67 bad: 68 kfree(lc); 69 return ret; 70 } 71 72 static void linear_dtr(struct dm_target *ti) 73 { 74 struct linear_c *lc = (struct linear_c *) ti->private; 75 76 dm_put_device(ti, lc->dev); 77 kfree(lc); 78 } 79 80 static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) 81 { 82 struct linear_c *lc = ti->private; 83 84 return lc->start + dm_target_offset(ti, bi_sector); 85 } 86 87 static int linear_map(struct dm_target *ti, struct bio *bio) 88 { 89 struct linear_c *lc = ti->private; 90 91 bio_set_dev(bio, lc->dev->bdev); 92 bio->bi_iter.bi_sector = linear_map_sector(ti, bio->bi_iter.bi_sector); 93 94 return DM_MAPIO_REMAPPED; 95 } 96 97 static void linear_status(struct dm_target *ti, status_type_t type, 98 unsigned status_flags, char *result, unsigned maxlen) 99 { 100 struct linear_c *lc = (struct linear_c *) ti->private; 101 size_t sz = 0; 102 103 switch (type) { 104 case STATUSTYPE_INFO: 105 result[0] = '\0'; 106 break; 107 108 case STATUSTYPE_TABLE: 109 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start); 110 break; 111 112 case STATUSTYPE_IMA: 113 DMEMIT_TARGET_NAME_VERSION(ti->type); 114 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name, 115 (unsigned long long)lc->start); 116 break; 117 } 118 } 119 120 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) 121 { 122 struct linear_c *lc = (struct linear_c *) ti->private; 123 struct dm_dev *dev = lc->dev; 124 125 *bdev = dev->bdev; 126 127 /* 128 * Only pass ioctls through if the device sizes match exactly. 129 */ 130 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev)) 131 return 1; 132 return 0; 133 } 134 135 #ifdef CONFIG_BLK_DEV_ZONED 136 static int linear_report_zones(struct dm_target *ti, 137 struct dm_report_zones_args *args, unsigned int nr_zones) 138 { 139 struct linear_c *lc = ti->private; 140 141 return dm_report_zones(lc->dev->bdev, lc->start, 142 linear_map_sector(ti, args->next_sector), 143 args, nr_zones); 144 } 145 #else 146 #define linear_report_zones NULL 147 #endif 148 149 static int linear_iterate_devices(struct dm_target *ti, 150 iterate_devices_callout_fn fn, void *data) 151 { 152 struct linear_c *lc = ti->private; 153 154 return fn(ti, lc->dev, lc->start, ti->len, data); 155 } 156 157 #if IS_ENABLED(CONFIG_FS_DAX) 158 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff) 159 { 160 struct linear_c *lc = ti->private; 161 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT); 162 163 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT; 164 return lc->dev->dax_dev; 165 } 166 167 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 168 long nr_pages, enum dax_access_mode mode, void **kaddr, 169 pfn_t *pfn) 170 { 171 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 172 173 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn); 174 } 175 176 static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff, 177 size_t nr_pages) 178 { 179 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 180 181 return dax_zero_page_range(dax_dev, pgoff, nr_pages); 182 } 183 184 static size_t linear_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff, 185 void *addr, size_t bytes, struct iov_iter *i) 186 { 187 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 188 189 return dax_recovery_write(dax_dev, pgoff, addr, bytes, i); 190 } 191 192 #else 193 #define linear_dax_direct_access NULL 194 #define linear_dax_zero_page_range NULL 195 #define linear_dax_recovery_write NULL 196 #endif 197 198 static struct target_type linear_target = { 199 .name = "linear", 200 .version = {1, 4, 0}, 201 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT | 202 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO, 203 .report_zones = linear_report_zones, 204 .module = THIS_MODULE, 205 .ctr = linear_ctr, 206 .dtr = linear_dtr, 207 .map = linear_map, 208 .status = linear_status, 209 .prepare_ioctl = linear_prepare_ioctl, 210 .iterate_devices = linear_iterate_devices, 211 .direct_access = linear_dax_direct_access, 212 .dax_zero_page_range = linear_dax_zero_page_range, 213 .dax_recovery_write = linear_dax_recovery_write, 214 }; 215 216 int __init dm_linear_init(void) 217 { 218 int r = dm_register_target(&linear_target); 219 220 if (r < 0) 221 DMERR("register failed %d", r); 222 223 return r; 224 } 225 226 void dm_linear_exit(void) 227 { 228 dm_unregister_target(&linear_target); 229 } 230