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) || op_is_zone_mgmt(bio_op(bio))) 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 size_t sz = 0; 110 111 switch (type) { 112 case STATUSTYPE_INFO: 113 result[0] = '\0'; 114 break; 115 116 case STATUSTYPE_TABLE: 117 DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start); 118 break; 119 120 case STATUSTYPE_IMA: 121 DMEMIT_TARGET_NAME_VERSION(ti->type); 122 DMEMIT(",device_name=%s,start=%llu;", lc->dev->name, 123 (unsigned long long)lc->start); 124 break; 125 } 126 } 127 128 static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) 129 { 130 struct linear_c *lc = (struct linear_c *) ti->private; 131 struct dm_dev *dev = lc->dev; 132 133 *bdev = dev->bdev; 134 135 /* 136 * Only pass ioctls through if the device sizes match exactly. 137 */ 138 if (lc->start || ti->len != bdev_nr_sectors(dev->bdev)) 139 return 1; 140 return 0; 141 } 142 143 #ifdef CONFIG_BLK_DEV_ZONED 144 static int linear_report_zones(struct dm_target *ti, 145 struct dm_report_zones_args *args, unsigned int nr_zones) 146 { 147 struct linear_c *lc = ti->private; 148 149 return dm_report_zones(lc->dev->bdev, lc->start, 150 linear_map_sector(ti, args->next_sector), 151 args, nr_zones); 152 } 153 #else 154 #define linear_report_zones NULL 155 #endif 156 157 static int linear_iterate_devices(struct dm_target *ti, 158 iterate_devices_callout_fn fn, void *data) 159 { 160 struct linear_c *lc = ti->private; 161 162 return fn(ti, lc->dev, lc->start, ti->len, data); 163 } 164 165 #if IS_ENABLED(CONFIG_FS_DAX) 166 static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff) 167 { 168 struct linear_c *lc = ti->private; 169 sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT); 170 171 *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT; 172 return lc->dev->dax_dev; 173 } 174 175 static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 176 long nr_pages, void **kaddr, 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, 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