diff options
Diffstat (limited to 'drivers/md/dm-linear.c')
| -rw-r--r-- | drivers/md/dm-linear.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c new file mode 100644 index 000000000..f4448d520 --- /dev/null +++ b/drivers/md/dm-linear.c @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2001-2003 Sistina Software (UK) Limited. + * + * This file is released under the GPL. + */ + +#include "dm.h" +#include <linux/module.h> +#include <linux/init.h> +#include <linux/blkdev.h> +#include <linux/bio.h> +#include <linux/dax.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "linear" + +/* + * Linear: maps a linear range of a device. + */ +struct linear_c { + struct dm_dev *dev; + sector_t start; +}; + +/* + * Construct a linear mapping: <dev_path> <offset> + */ +static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv) +{ + struct linear_c *lc; + unsigned long long tmp; + char dummy; + int ret; + + if (argc != 2) { + ti->error = "Invalid argument count"; + return -EINVAL; + } + + lc = kmalloc(sizeof(*lc), GFP_KERNEL); + if (lc == NULL) { + ti->error = "Cannot allocate linear context"; + return -ENOMEM; + } + + ret = -EINVAL; + if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) { + ti->error = "Invalid device sector"; + goto bad; + } + lc->start = tmp; + + ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev); + if (ret) { + ti->error = "Device lookup failed"; + goto bad; + } + + ti->num_flush_bios = 1; + ti->num_discard_bios = 1; + ti->num_secure_erase_bios = 1; + ti->num_write_zeroes_bios = 1; + ti->private = lc; + return 0; + +bad: + kfree(lc); + return ret; +} + +static void linear_dtr(struct dm_target *ti) +{ + struct linear_c *lc = ti->private; + + dm_put_device(ti, lc->dev); + kfree(lc); +} + +static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector) +{ + struct linear_c *lc = ti->private; + + return lc->start + dm_target_offset(ti, bi_sector); +} + +static int linear_map(struct dm_target *ti, struct bio *bio) +{ + struct linear_c *lc = ti->private; + + bio_set_dev(bio, lc->dev->bdev); + bio->bi_iter.bi_sector = linear_map_sector(ti, bio->bi_iter.bi_sector); + + return DM_MAPIO_REMAPPED; +} + +static void linear_status(struct dm_target *ti, status_type_t type, + unsigned int status_flags, char *result, unsigned int maxlen) +{ + struct linear_c *lc = ti->private; + size_t sz = 0; + + switch (type) { + case STATUSTYPE_INFO: + result[0] = '\0'; + break; + + case STATUSTYPE_TABLE: + DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start); + break; + + case STATUSTYPE_IMA: + DMEMIT_TARGET_NAME_VERSION(ti->type); + DMEMIT(",device_name=%s,start=%llu;", lc->dev->name, + (unsigned long long)lc->start); + break; + } +} + +static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev) +{ + struct linear_c *lc = ti->private; + struct dm_dev *dev = lc->dev; + + *bdev = dev->bdev; + + /* + * Only pass ioctls through if the device sizes match exactly. + */ + if (lc->start || ti->len != bdev_nr_sectors(dev->bdev)) + return 1; + return 0; +} + +#ifdef CONFIG_BLK_DEV_ZONED +static int linear_report_zones(struct dm_target *ti, + struct dm_report_zones_args *args, unsigned int nr_zones) +{ + struct linear_c *lc = ti->private; + + return dm_report_zones(lc->dev->bdev, lc->start, + linear_map_sector(ti, args->next_sector), + args, nr_zones); +} +#else +#define linear_report_zones NULL +#endif + +static int linear_iterate_devices(struct dm_target *ti, + iterate_devices_callout_fn fn, void *data) +{ + struct linear_c *lc = ti->private; + + return fn(ti, lc->dev, lc->start, ti->len, data); +} + +#if IS_ENABLED(CONFIG_FS_DAX) +static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff) +{ + struct linear_c *lc = ti->private; + sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT); + + *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT; + return lc->dev->dax_dev; +} + +static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, + long nr_pages, enum dax_access_mode mode, void **kaddr, + pfn_t *pfn) +{ + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); + + return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn); +} + +static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff, + size_t nr_pages) +{ + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); + + return dax_zero_page_range(dax_dev, pgoff, nr_pages); +} + +static size_t linear_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff, + void *addr, size_t bytes, struct iov_iter *i) +{ + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff); + + return dax_recovery_write(dax_dev, pgoff, addr, bytes, i); +} + +#else +#define linear_dax_direct_access NULL +#define linear_dax_zero_page_range NULL +#define linear_dax_recovery_write NULL +#endif + +static struct target_type linear_target = { + .name = "linear", + .version = {1, 4, 0}, + .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT | + DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO, + .report_zones = linear_report_zones, + .module = THIS_MODULE, + .ctr = linear_ctr, + .dtr = linear_dtr, + .map = linear_map, + .status = linear_status, + .prepare_ioctl = linear_prepare_ioctl, + .iterate_devices = linear_iterate_devices, + .direct_access = linear_dax_direct_access, + .dax_zero_page_range = linear_dax_zero_page_range, + .dax_recovery_write = linear_dax_recovery_write, +}; + +int __init dm_linear_init(void) +{ + int r = dm_register_target(&linear_target); + + if (r < 0) + DMERR("register failed %d", r); + + return r; +} + +void dm_linear_exit(void) +{ + dm_unregister_target(&linear_target); +} |