Монтирование device-mapper устройства при загрузке системы

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/version.h>
#include <linux/fs.h>
#include <linux/device-mapper.h>
 
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32)
#include <linux/bio.h>
#endif
 
#include <linux/fs.h>
#include <linux/kdev_t.h>
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
#include <linux/mm.h>
#endif
 
struct Sddm_target
{
    struct dm_dev *dev;
    sector_t start;
};
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
static int sddm_target_map(struct dm_target *ti, struct buffer_head *bh, int rw, union map_info *map_context)
#elif LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32)
static int sddm_target_map(struct dm_target *ti, struct bio *bio, union map_info *map_context)
#else
static int sddm_target_map(struct dm_target *ti, struct bio *bio)
#endif
{
    struct Sddm_target *mdt;
 
    mdt = (struct Sddm_target *) ti->private;
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
    bh->b_dev = mdt->dev->dev;
#else
    bio->bi_bdev = mdt->dev->bdev;
#endif
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
    submit_bh(rw, bh);
#elif LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,32)
    submit_bio(bio->bi_rw, bio);
#else
    submit_bio(bio);
#endif
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
    return 0;
#else
    return DM_MAPIO_SUBMITTED;
#endif
}
 
static int sddm_target_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
    struct Sddm_target *mdt;
    unsigned long start;
    unsigned long len;
    int err;
 
    if (argc != 2)
    {
        ti->error = "Invalid argument count";
        return -EINVAL;
    }
 
    mdt = (struct Sddm_target*)kmalloc(sizeof(struct Sddm_target), GFP_KERNEL);
 
    if (mdt == NULL)
    {
        printk(KERN_CRIT "\n Mdt is null\n");
        ti->error = "dm-basic_target: Cannot allocate linear context";
        return -ENOMEM;
    }       
 
    if (sscanf(argv[1], "%lu", &start) != 1)
    {
        ti->error = "dm-basic_target: Invalid deviceee sector";
        kfree(mdt);
        printk(KERN_CRIT "\n>>out function basic_target_ctr with errorrrrrrrrrr \n");           
        return -EINVAL;
    }
 
    mdt->start = (sector_t)start;
 
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,4,32)
    err = dm_get_device(ti, argv[0], ti->begin, ti->len, dm_table_get_mode(ti->table), &mdt->dev);
#else
    err = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &mdt->dev);
#endif
    if (err)
    {
        ti->error = "dm-basic_target: Device lookup failed";
        kfree(mdt);
        return -EINVAL;
    }
 
    ti->private = mdt;
 
    return 0;
}
 
static void sddm_target_dtr(struct dm_target *ti)
{
    struct Sddm_target *mdt = (struct Sddm_target *) ti->private;
 
    dm_put_device(ti, mdt->dev);
    kfree(mdt);
}
 
static struct target_type sddm_target = {
        .name = "sddm_target",
        .version = {1,0,0},
        .module = THIS_MODULE,
        .ctr = sddm_target_ctr,
        .dtr = sddm_target_dtr,
        .map = sddm_target_map,
};
 
static int __init init_sddm_target(void)
{
    int result;
 
    result = dm_register_target(&sddm_target);
 
    return 0;
}
 
static void __exit cleanup_sddm_target(void)
{
    dm_unregister_target(&sddm_target);
}
 
module_init(init_sddm_target);
 
module_exit(cleanup_sddm_target);
 
MODULE_LICENSE("GPL");