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_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) || op_is_zone_mgmt(bio_op(bio))) 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 void linear_status(struct dm_target *ti, status_type_t type, 105 unsigned status_flags, char *result, unsigned maxlen) 106 { 107 struct linear_c *lc = (struct linear_c *) ti->private; 108 size_t sz = 0; 109 110 switch (type) { 111 case STATUSTYPE_INFO: 112 result[0] = '\0'; 113 break; 114 115 case STATUSTYPE_TABLE: 116 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start); 117 break; 118 119 case STATUSTYPE_IMA: 120 DMEMIT_TARGET_NAME_VERSION(ti->type); 121 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name, 122 (unsigned long long)lc->start); 123 break; 124 } 125 } 126 127 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) 128 { 129 struct linear_c *lc = (struct linear_c *) ti->private; 130 struct dm_dev *dev = lc->dev; 131 132 *bdev = dev->bdev; 133 134 /* 135 * Only pass ioctls through if the device sizes match exactly. 136 */ 137 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev)) 138 return 1; 139 return 0; 140 } 141 142 #ifdef CONFIG_BLK_DEV_ZONED 143 static int linear_report_zones(struct dm_target *ti, 144 struct dm_report_zones_args *args, unsigned int nr_zones) 145 { 146 struct linear_c *lc = ti->private; 147 148 return dm_report_zones(lc->dev->bdev, lc->start, 149 linear_map_sector(ti, args->next_sector), 150 args, nr_zones); 151 } 152 #else 153 #define linear_report_zones NULL 154 #endif 155 156 static int linear_iterate_devices(struct dm_target *ti, 157 iterate_devices_callout_fn fn, void *data) 158 { 159 struct linear_c *lc = ti->private; 160 161 return fn(ti, lc->dev, lc->start, ti->len, data); 162 } 163 164 #if IS_ENABLED(CONFIG_FS_DAX) 165 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff) 166 { 167 struct linear_c *lc = ti->private; 168 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT); 169 170 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT; 171 return lc->dev->dax_dev; 172 } 173 174 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 175 long nr_pages, enum dax_access_mode mode, void **kaddr, 176 pfn_t *pfn) 177 { 178 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 179 180 return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn); 181 } 182 183 static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff, 184 size_t nr_pages) 185 { 186 struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); 187 188 return dax_zero_page_range(dax_dev, pgoff, nr_pages); 189 } 190 191 #else 192 #define linear_dax_direct_access NULL 193 #define linear_dax_zero_page_range NULL 194 #endif 195 196 static struct target_type linear_target = { 197 .name = "linear", 198 .version = {1, 4, 0}, 199 .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT | 200 DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO, 201 .report_zones = linear_report_zones, 202 .module = THIS_MODULE, 203 .ctr = linear_ctr, 204 .dtr = linear_dtr, 205 .map = linear_map, 206 .status = linear_status, 207 .prepare_ioctl = linear_prepare_ioctl, 208 .iterate_devices = linear_iterate_devices, 209 .direct_access = linear_dax_direct_access, 210 .dax_zero_page_range = linear_dax_zero_page_range, 211 }; 212 213 int __init dm_linear_init(void) 214 { 215 int r = dm_register_target(&linear_target); 216 217 if (r < 0) 218 DMERR("register failed %d", r); 219 220 return r; 221 } 222 223 void dm_linear_exit(void) 224 { 225 dm_unregister_target(&linear_target); 226 } 227