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_same_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 = (struct linear_c *) 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 void linear_map_bio(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 if (bio_sectors(bio) || op_is_zone_mgmt(bio_op(bio))) 94 bio->bi_iter.bi_sector = 95 linear_map_sector(ti, bio->bi_iter.bi_sector); 96 } 97 98 static int linear_map(struct dm_target *ti, struct bio *bio) 99 { 100 linear_map_bio(ti, bio); 101 102 return DM_MAPIO_REMAPPED; 103 } 104 105 static void linear_status(struct dm_target *ti, status_type_t type, 106 unsigned status_flags, char *result, unsigned maxlen) 107 { 108 struct linear_c *lc = (struct linear_c *) ti->private; 109 110 switch (type) { 111 case STATUSTYPE_INFO: 112 result[0] = '\0'; 113 break; 114 115 case STATUSTYPE_TABLE: 116 snprintf(result, maxlen, "%s %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 = (struct linear_c *) 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 || 133 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) 134 return 1; 135 return 0; 136 } 137 138 #ifdef CONFIG_BLK_DEV_ZONED 139 static int linear_report_zones(struct dm_target *ti, 140 struct dm_report_zones_args *args, unsigned int nr_zones) 141 { 142 struct linear_c *lc = ti->private; 143 sector_t sector = linear_map_sector(ti, args->next_sector); 144 145 args->start = lc->start; 146 return blkdev_report_zones(lc->dev->bdev, sector, nr_zones, 147 dm_report_zones_cb, args); 148 } 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_DAX_DRIVER) 160 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 161 long nr_pages, void **kaddr, pfn_t *pfn) 162 { 163 long ret; 164 struct linear_c *lc = ti->private; 165 struct block_device *bdev = lc->dev->bdev; 166 struct dax_device *dax_dev = lc->dev->dax_dev; 167 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 168 169 dev_sector = linear_map_sector(ti, sector); 170 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); 171 if (ret) 172 return ret; 173 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); 174 } 175 176 static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff, 177 void *addr, size_t bytes, struct iov_iter *i) 178 { 179 struct linear_c *lc = ti->private; 180 struct block_device *bdev = lc->dev->bdev; 181 struct dax_device *dax_dev = lc->dev->dax_dev; 182 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 183 184 dev_sector = linear_map_sector(ti, sector); 185 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 186 return 0; 187 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i); 188 } 189 190 static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff, 191 void *addr, size_t bytes, struct iov_iter *i) 192 { 193 struct linear_c *lc = ti->private; 194 struct block_device *bdev = lc->dev->bdev; 195 struct dax_device *dax_dev = lc->dev->dax_dev; 196 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 197 198 dev_sector = linear_map_sector(ti, sector); 199 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 200 return 0; 201 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i); 202 } 203 204 #else 205 #define linear_dax_direct_access NULL 206 #define linear_dax_copy_from_iter NULL 207 #define linear_dax_copy_to_iter NULL 208 #endif 209 210 static struct target_type linear_target = { 211 .name = "linear", 212 .version = {1, 4, 0}, 213 #ifdef CONFIG_BLK_DEV_ZONED 214 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM, 215 .report_zones = linear_report_zones, 216 #else 217 .features = DM_TARGET_PASSES_INTEGRITY, 218 #endif 219 .module = THIS_MODULE, 220 .ctr = linear_ctr, 221 .dtr = linear_dtr, 222 .map = linear_map, 223 .status = linear_status, 224 .prepare_ioctl = linear_prepare_ioctl, 225 .iterate_devices = linear_iterate_devices, 226 .direct_access = linear_dax_direct_access, 227 .dax_copy_from_iter = linear_dax_copy_from_iter, 228 .dax_copy_to_iter = linear_dax_copy_to_iter, 229 }; 230 231 int __init dm_linear_init(void) 232 { 233 int r = dm_register_target(&linear_target); 234 235 if (r < 0) 236 DMERR("register failed %d", r); 237 238 return r; 239 } 240 241 void dm_linear_exit(void) 242 { 243 dm_unregister_target(&linear_target); 244 } 245