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_write_same_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 void linear_map_bio(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 if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) 93 bio->bi_iter.bi_sector = 94 linear_map_sector(ti, bio->bi_iter.bi_sector); 95 } 96 97 static int linear_map(struct dm_target *ti, struct bio *bio) 98 { 99 linear_map_bio(ti, bio); 100 101 return DM_MAPIO_REMAPPED; 102 } 103 104 static int linear_end_io(struct dm_target *ti, struct bio *bio, 105 blk_status_t *error) 106 { 107 struct linear_c *lc = ti->private; 108 109 if (!*error && bio_op(bio) == REQ_OP_ZONE_REPORT) 110 dm_remap_zone_report(ti, bio, lc->start); 111 112 return DM_ENDIO_DONE; 113 } 114 115 static void linear_status(struct dm_target *ti, status_type_t type, 116 unsigned status_flags, char *result, unsigned maxlen) 117 { 118 struct linear_c *lc = (struct linear_c *) ti->private; 119 120 switch (type) { 121 case STATUSTYPE_INFO: 122 result[0] = '\0'; 123 break; 124 125 case STATUSTYPE_TABLE: 126 snprintf(result, maxlen, "%s %llu", lc->dev->name, 127 (unsigned long long)lc->start); 128 break; 129 } 130 } 131 132 static int linear_prepare_ioctl(struct dm_target *ti, 133 struct block_device **bdev, fmode_t *mode) 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 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 158 long nr_pages, void **kaddr, pfn_t *pfn) 159 { 160 long ret; 161 struct linear_c *lc = ti->private; 162 struct block_device *bdev = lc->dev->bdev; 163 struct dax_device *dax_dev = lc->dev->dax_dev; 164 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 165 166 dev_sector = linear_map_sector(ti, sector); 167 ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff); 168 if (ret) 169 return ret; 170 return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); 171 } 172 173 static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff, 174 void *addr, size_t bytes, struct iov_iter *i) 175 { 176 struct linear_c *lc = ti->private; 177 struct block_device *bdev = lc->dev->bdev; 178 struct dax_device *dax_dev = lc->dev->dax_dev; 179 sector_t dev_sector, sector = pgoff * PAGE_SECTORS; 180 181 dev_sector = linear_map_sector(ti, sector); 182 if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff)) 183 return 0; 184 return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i); 185 } 186 187 static struct target_type linear_target = { 188 .name = "linear", 189 .version = {1, 4, 0}, 190 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM, 191 .module = THIS_MODULE, 192 .ctr = linear_ctr, 193 .dtr = linear_dtr, 194 .map = linear_map, 195 .end_io = linear_end_io, 196 .status = linear_status, 197 .prepare_ioctl = linear_prepare_ioctl, 198 .iterate_devices = linear_iterate_devices, 199 .direct_access = linear_dax_direct_access, 200 .dax_copy_from_iter = linear_dax_copy_from_iter, 201 }; 202 203 int __init dm_linear_init(void) 204 { 205 int r = dm_register_target(&linear_target); 206 207 if (r < 0) 208 DMERR("register failed %d", r); 209 210 return r; 211 } 212 213 void dm_linear_exit(void) 214 { 215 dm_unregister_target(&linear_target); 216 } 217