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/*
* Copyright (C) 2017 Intel Corporation.
*
* 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/slab.h>
#include <linux/bitops.h>
#include <linux/device-mapper.h>
struct unstripe_c {
struct dm_dev *dev;
sector_t physical_start;
uint32_t stripes;
uint32_t unstripe;
sector_t unstripe_width;
sector_t unstripe_offset;
uint32_t chunk_size;
u8 chunk_shift;
};
#define DM_MSG_PREFIX "unstriped"
static void cleanup_unstripe(struct unstripe_c *uc, struct dm_target *ti)
{
if (uc->dev)
dm_put_device(ti, uc->dev);
kfree(uc);
}
/*
* Contruct an unstriped mapping.
* <number of stripes> <chunk size> <stripe #> <dev_path> <offset>
*/
static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct unstripe_c *uc;
sector_t tmp_len;
unsigned long long start;
char dummy;
if (argc != 5) {
ti->error = "Invalid number of arguments";
return -EINVAL;
}
uc = kzalloc(sizeof(*uc), GFP_KERNEL);
if (!uc) {
ti->error = "Memory allocation for unstriped context failed";
return -ENOMEM;
}
if (kstrtouint(argv[0], 10, &uc->stripes) || !uc->stripes) {
ti->error = "Invalid stripe count";
goto err;
}
if (kstrtouint(argv[1], 10, &uc->chunk_size) || !uc->chunk_size) {
ti->error = "Invalid chunk_size";
goto err;
}
// FIXME: must support non power of 2 chunk_size, dm-stripe.c does
if (!is_power_of_2(uc->chunk_size)) {
ti->error = "Non power of 2 chunk_size is not supported yet";
goto err;
}
if (kstrtouint(argv[2], 10, &uc->unstripe)) {
ti->error = "Invalid stripe number";
goto err;
}
if (uc->unstripe > uc->stripes && uc->stripes > 1) {
ti->error = "Please provide stripe between [0, # of stripes]";
goto err;
}
if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &uc->dev)) {
ti->error = "Couldn't get striped device";
goto err;
}
if (sscanf(argv[4], "%llu%c", &start, &dummy) != 1) {
ti->error = "Invalid striped device offset";
goto err;
}
uc->physical_start = start;
uc->unstripe_offset = uc->unstripe * uc->chunk_size;
uc->unstripe_width = (uc->stripes - 1) * uc->chunk_size;
uc->chunk_shift = fls(uc->chunk_size) - 1;
tmp_len = ti->len;
if (sector_div(tmp_len, uc->chunk_size)) {
ti->error = "Target length not divisible by chunk size";
goto err;
}
if (dm_set_target_max_io_len(ti, uc->chunk_size)) {
ti->error = "Failed to set max io len";
goto err;
}
ti->private = uc;
return 0;
err:
cleanup_unstripe(uc, ti);
return -EINVAL;
}
static void unstripe_dtr(struct dm_target *ti)
{
struct unstripe_c *uc = ti->private;
cleanup_unstripe(uc, ti);
}
static sector_t map_to_core(struct dm_target *ti, struct bio *bio)
{
struct unstripe_c *uc = ti->private;
sector_t sector = bio->bi_iter.bi_sector;
/* Shift us up to the right "row" on the stripe */
sector += uc->unstripe_width * (sector >> uc->chunk_shift);
/* Account for what stripe we're operating on */
sector += uc->unstripe_offset;
return sector;
}
static int unstripe_map(struct dm_target *ti, struct bio *bio)
{
struct unstripe_c *uc = ti->private;
bio_set_dev(bio, uc->dev->bdev);
bio->bi_iter.bi_sector = map_to_core(ti, bio) + uc->physical_start;
return DM_MAPIO_REMAPPED;
}
static void unstripe_status(struct dm_target *ti, status_type_t type,
unsigned int status_flags, char *result, unsigned int maxlen)
{
struct unstripe_c *uc = ti->private;
unsigned int sz = 0;
switch (type) {
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
DMEMIT("%d %llu %d %s %llu",
uc->stripes, (unsigned long long)uc->chunk_size, uc->unstripe,
uc->dev->name, (unsigned long long)uc->physical_start);
break;
}
}
static int unstripe_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct unstripe_c *uc = ti->private;
return fn(ti, uc->dev, uc->physical_start, ti->len, data);
}
static void unstripe_io_hints(struct dm_target *ti,
struct queue_limits *limits)
{
struct unstripe_c *uc = ti->private;
limits->chunk_sectors = uc->chunk_size;
}
static struct target_type unstripe_target = {
.name = "unstriped",
.version = {1, 0, 0},
.module = THIS_MODULE,
.ctr = unstripe_ctr,
.dtr = unstripe_dtr,
.map = unstripe_map,
.status = unstripe_status,
.iterate_devices = unstripe_iterate_devices,
.io_hints = unstripe_io_hints,
};
static int __init dm_unstripe_init(void)
{
int r;
r = dm_register_target(&unstripe_target);
if (r < 0)
DMERR("target registration failed");
return r;
}
static void __exit dm_unstripe_exit(void)
{
dm_unregister_target(&unstripe_target);
}
module_init(dm_unstripe_init);
module_exit(dm_unstripe_exit);
MODULE_DESCRIPTION(DM_NAME " unstriped target");
MODULE_AUTHOR("Scott Bauer <scott.bauer@intel.com>");
MODULE_LICENSE("GPL");
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