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/*

   linear.c : Multiple Devices driver for Linux

              Copyright (C) 1994-96 Marc ZYNGIER

              <zyngier@ufr-info-p7.ibp.fr> or

              <maz@gloups.fdn.fr>

   Linear mode management functions.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2, or (at your option)

   any later version.

   You should have received a copy of the GNU General Public License

   (for example /usr/src/linux/COPYING); if not, write to the Free

   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <linux/module.h>

#include <linux/md.h>

#include <linux/linear.h>

#include <linux/malloc.h>

#define MAJOR_NR MD_MAJOR

#define MD_DRIVER

#define MD_PERSONALITY

static int linear_run (int minor, struct md_dev *mddev)

{

  int cur=0, i, size, dev0_size, nb_zone;

  struct linear_data *data;

  MOD_INC_USE_COUNT;

  mddev->private=kmalloc (sizeof (struct linear_data), GFP_KERNEL);

  data=(struct linear_data *) mddev->private;

  /*

     Find out the smallest device. This was previously done

     at registry time, but since it violates modularity,

     I moved it here... Any comment ? ;-)

   */

  data->smallest=mddev->devices;

  for (i=1; i<mddev->nb_dev; i++)

    if (data->smallest->size > mddev->devices[i].size)

      data->smallest=mddev->devices+i;

  nb_zone=data->nr_zones=

    md_size[minor]/data->smallest->size +

    (md_size[minor]%data->smallest->size ? 1 : 0);

  data->hash_table=kmalloc (sizeof (struct linear_hash)*nb_zone, GFP_KERNEL);

  size=mddev->devices[cur].size;

  i=0;

  while (cur<mddev->nb_dev)

  {

    data->hash_table[i].dev0=mddev->devices+cur;

    if (size>=data->smallest->size) /* If we completely fill the slot */

    {

      data->hash_table[i++].dev1=NULL;

      size-=data->smallest->size;

      if (!size)

      {

        if (++cur==mddev->nb_dev) continue;

        size=mddev->devices[cur].size;

      }

      continue;

    }

    if (++cur==mddev->nb_dev) /* Last dev, set dev1 as NULL */

    {

      data->hash_table[i].dev1=NULL;

      continue;

    }

    dev0_size=size;             /* Here, we use a 2nd dev to fill the slot */

    size=mddev->devices[cur].size;

    data->hash_table[i++].dev1=mddev->devices+cur;

    size-=(data->smallest->size - dev0_size);

  }

  return 0;

}

static int linear_stop (int minor, struct md_dev *mddev)

{

  struct linear_data *data=(struct linear_data *) mddev->private;

  kfree (data->hash_table);

  kfree (data);

  MOD_DEC_USE_COUNT;

  return 0;

}

static int linear_map (struct md_dev *mddev, kdev_t *rdev,

                       unsigned long *rsector, unsigned long size)

{

  struct linear_data *data=(struct linear_data *) mddev->private;

  struct linear_hash *hash;

  struct real_dev *tmp_dev;

  long block;

  block=*rsector >> 1;

  hash=data->hash_table+(block/data->smallest->size);

  if (block >= (hash->dev0->size + hash->dev0->offset))

  {

    if (!hash->dev1)

    {

      printk ("linear_map : hash->dev1==NULL for block %ld\n", block);

      return (-1);

    }

    tmp_dev=hash->dev1;

  }

  else

    tmp_dev=hash->dev0;

  if (block >= (tmp_dev->size + tmp_dev->offset) || block < tmp_dev->offset)

    printk ("Block %ld out of bounds on dev %s size %d offset %d\n",

            block, kdevname(tmp_dev->dev), tmp_dev->size, tmp_dev->offset);

  *rdev=tmp_dev->dev;

  *rsector=(block-(tmp_dev->offset)) << 1;

  return (0);

}

static int linear_status (char *page, int minor, struct md_dev *mddev)

{

  int sz=0;

#undef MD_DEBUG

#ifdef MD_DEBUG

  int j;

  struct linear_data *data=(struct linear_data *) mddev->private;

  sz+=sprintf (page+sz, "      ");

  for (j=0; j<data->nr_zones; j++)

  {

    sz+=sprintf (page+sz, "[%s",

                 partition_name (data->hash_table[j].dev0->dev));

    if (data->hash_table[j].dev1)

      sz+=sprintf (page+sz, "/%s] ",

                   partition_name(data->hash_table[j].dev1->dev));

    else

      sz+=sprintf (page+sz, "] ");

  }

  sz+=sprintf (page+sz, "\n");

#endif

  sz+=sprintf (page+sz, " %dk rounding", 1<<FACTOR_SHIFT(FACTOR(mddev)));

  return sz;

}

static struct md_personality linear_personality=

{

  "linear",

  linear_map,

  NULL,

  NULL,

  linear_run,

  linear_stop,

  linear_status,

  NULL,                         /* no ioctls */

};

#ifndef MODULE

void linear_init (void)

{

  register_md_personality (LINEAR, &linear_personality);

}

#else

int init_module (void)

{

  return (register_md_personality (LINEAR, &linear_personality));

}

void cleanup_module (void)

{

  unregister_md_personality (LINEAR);

}

#endif