| 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 | } |