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/*
* 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) {
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_write_same_bios = 1;
ti->private = lc;
return 0;
bad:
kfree(lc);
return ret;
}
static void linear_dtr(struct dm_target *ti)
{
struct linear_c *lc = (struct linear_c *) 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 void linear_map_bio(struct dm_target *ti, struct bio *bio)
{
struct linear_c *lc = ti->private;
bio->bi_bdev = lc->dev->bdev;
if (bio_sectors(bio))
bio->bi_iter.bi_sector =
linear_map_sector(ti, bio->bi_iter.bi_sector);
}
static int linear_map(struct dm_target *ti, struct bio *bio)
{
linear_map_bio(ti, bio);
return DM_MAPIO_REMAPPED;
}
static void linear_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct linear_c *lc = (struct linear_c *) ti->private;
switch (type) {
case STATUSTYPE_INFO:
result[0] = '\0';
break;
case STATUSTYPE_TABLE:
snprintf(result, maxlen, "%s %llu", lc->dev->name,
(unsigned long long)lc->start);
break;
}
}
static int linear_prepare_ioctl(struct dm_target *ti,
struct block_device **bdev, fmode_t *mode)
{
struct linear_c *lc = (struct linear_c *) 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 != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
return 1;
return 0;
}
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);
}
static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
long ret;
struct linear_c *lc = ti->private;
struct block_device *bdev = lc->dev->bdev;
struct dax_device *dax_dev = lc->dev->dax_dev;
sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
dev_sector = linear_map_sector(ti, sector);
ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
if (ret)
return ret;
return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
}
static struct target_type linear_target = {
.name = "linear",
.version = {1, 3, 0},
.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,
};
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);
}
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