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) || bio_op(bio) == REQ_OP_ZONE_RESET) 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, sector_t sector, 140 struct blk_zone *zones, unsigned int *nr_zones, 141 gfp_t gfp_mask) 142 { 143 struct linear_c *lc = (struct linear_c *) ti->private; 144 int ret; 145 146 /* Do report and remap it */ 147 ret = blkdev_report_zones(lc->dev->bdev, linear_map_sector(ti, sector), 148 zones, nr_zones, gfp_mask); 149 if (ret != 0) 150 return ret; 151 152 if (*nr_zones) 153 dm_remap_zone_report(ti, lc->start, zones, nr_zones); 154 return 0; 155 } 156 #endif 157 158 static int linear_iterate_devices(struct dm_target *ti, 159 iterate_devices_callout_fn fn, void *data) 160 { 161 struct linear_c *lc = ti->private; 162 163 return fn(ti, lc->dev, lc->start, ti->len, data); 164 } 165 166 #if IS_ENABLED(CONFIG_DAX_DRIVER) 167 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 168 long nr_pages, void **kaddr, pfn_t *pfn) 169 { 170 long ret; 171 struct linear_c *lc = ti->private; 172 struct block_device *bdev = lc->dev->bdev; 173 struct dax_device *dax_dev = lc->dev->dax_dev; 174 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 175 176 dev_sector = linear_map_sector(ti, sector); 177 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); 178 if (ret) 179 return ret; 180 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); 181 } 182 183 static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff, 184 void *addr, size_t bytes, struct iov_iter *i) 185 { 186 struct linear_c *lc = ti->private; 187 struct block_device *bdev = lc->dev->bdev; 188 struct dax_device *dax_dev = lc->dev->dax_dev; 189 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 190 191 dev_sector = linear_map_sector(ti, sector); 192 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 193 return 0; 194 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i); 195 } 196 197 static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff, 198 void *addr, size_t bytes, struct iov_iter *i) 199 { 200 struct linear_c *lc = ti->private; 201 struct block_device *bdev = lc->dev->bdev; 202 struct dax_device *dax_dev = lc->dev->dax_dev; 203 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 204 205 dev_sector = linear_map_sector(ti, sector); 206 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 207 return 0; 208 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i); 209 } 210 211 #else 212 #define linear_dax_direct_access NULL 213 #define linear_dax_copy_from_iter NULL 214 #define linear_dax_copy_to_iter NULL 215 #endif 216 217 static struct target_type linear_target = { 218 .name = "linear", 219 .version = {1, 4, 0}, 220 #ifdef CONFIG_BLK_DEV_ZONED 221 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM, 222 .report_zones = linear_report_zones, 223 #else 224 .features = DM_TARGET_PASSES_INTEGRITY, 225 #endif 226 .module = THIS_MODULE, 227 .ctr = linear_ctr, 228 .dtr = linear_dtr, 229 .map = linear_map, 230 .status = linear_status, 231 .prepare_ioctl = linear_prepare_ioctl, 232 .iterate_devices = linear_iterate_devices, 233 .direct_access = linear_dax_direct_access, 234 .dax_copy_from_iter = linear_dax_copy_from_iter, 235 .dax_copy_to_iter = linear_dax_copy_to_iter, 236 }; 237 238 int __init dm_linear_init(void) 239 { 240 int r = dm_register_target(&linear_target); 241 242 if (r < 0) 243 DMERR("register failed %d", r); 244 245 return r; 246 } 247 248 void dm_linear_exit(void) 249 { 250 dm_unregister_target(&linear_target); 251 } 252