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) { 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 int linear_end_io(struct dm_target *ti, struct bio *bio, 106 blk_status_t *error) 107 { 108 struct linear_c *lc = ti->private; 109 110 if (!*error && bio_op(bio) == REQ_OP_ZONE_REPORT) 111 dm_remap_zone_report(ti, bio, lc->start); 112 113 return DM_ENDIO_DONE; 114 } 115 116 static void linear_status(struct dm_target *ti, status_type_t type, 117 unsigned status_flags, char *result, unsigned maxlen) 118 { 119 struct linear_c *lc = (struct linear_c *) ti->private; 120 121 switch (type) { 122 case STATUSTYPE_INFO: 123 result[0] = '\0'; 124 break; 125 126 case STATUSTYPE_TABLE: 127 snprintf(result, maxlen, "%s %llu", lc->dev->name, 128 (unsigned long long)lc->start); 129 break; 130 } 131 } 132 133 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) 134 { 135 struct linear_c *lc = (struct linear_c *) ti->private; 136 struct dm_dev *dev = lc->dev; 137 138 *bdev = dev->bdev; 139 140 /* 141 * Only pass ioctls through if the device sizes match exactly. 142 */ 143 if (lc->start || 144 ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT) 145 return 1; 146 return 0; 147 } 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_DAX_DRIVER) 158 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 159 long nr_pages, void **kaddr, pfn_t *pfn) 160 { 161 long ret; 162 struct linear_c *lc = ti->private; 163 struct block_device *bdev = lc->dev->bdev; 164 struct dax_device *dax_dev = lc->dev->dax_dev; 165 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 166 167 dev_sector = linear_map_sector(ti, sector); 168 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); 169 if (ret) 170 return ret; 171 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); 172 } 173 174 static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff, 175 void *addr, size_t bytes, struct iov_iter *i) 176 { 177 struct linear_c *lc = ti->private; 178 struct block_device *bdev = lc->dev->bdev; 179 struct dax_device *dax_dev = lc->dev->dax_dev; 180 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 181 182 dev_sector = linear_map_sector(ti, sector); 183 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 184 return 0; 185 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i); 186 } 187 188 static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff, 189 void *addr, size_t bytes, struct iov_iter *i) 190 { 191 struct linear_c *lc = ti->private; 192 struct block_device *bdev = lc->dev->bdev; 193 struct dax_device *dax_dev = lc->dev->dax_dev; 194 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 195 196 dev_sector = linear_map_sector(ti, sector); 197 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 198 return 0; 199 return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i); 200 } 201 202 #else 203 #define linear_dax_direct_access NULL 204 #define linear_dax_copy_from_iter NULL 205 #define linear_dax_copy_to_iter NULL 206 #endif 207 208 static struct target_type linear_target = { 209 .name = "linear", 210 .version = {1, 4, 0}, 211 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM, 212 .module = THIS_MODULE, 213 .ctr = linear_ctr, 214 .dtr = linear_dtr, 215 .map = linear_map, 216 .end_io = linear_end_io, 217 .status = linear_status, 218 .prepare_ioctl = linear_prepare_ioctl, 219 .iterate_devices = linear_iterate_devices, 220 .direct_access = linear_dax_direct_access, 221 .dax_copy_from_iter = linear_dax_copy_from_iter, 222 .dax_copy_to_iter = linear_dax_copy_to_iter, 223 }; 224 225 int __init dm_linear_init(void) 226 { 227 int r = dm_register_target(&linear_target); 228 229 if (r < 0) 230 DMERR("register failed %d", r); 231 232 return r; 233 } 234 235 void dm_linear_exit(void) 236 { 237 dm_unregister_target(&linear_target); 238 } 239