drivers/block/linear.c

   1
   2 /*
   3    linear.c : Multiple Devices driver for Linux
   4               Copyright (C) 1994-96 Marc ZYNGIER
   5               <zyngier@ufr-info-p7.ibp.fr> or
   6               <maz@gloups.fdn.fr>
   7
   8    Linear mode management functions.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2, or (at your option)
  13    any later version.
  14
  15    You should have received a copy of the GNU General Public License
  16    (for example /usr/src/linux/COPYING); if not, write to the Free
  17    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #include <linux/module.h>
  21
  22 #include <linux/md.h>
  23 #include <linux/malloc.h>
  24 #include <linux/init.h>
  25
  26 #include "linear.h"
  27
  28 #define MAJOR_NR MD_MAJOR
  29 #define MD_DRIVER
  30 #define MD_PERSONALITY
  31
  32 static int linear_run (int minor, struct md_dev *mddev)
  33 {
  34   int cur=0, i, size, dev0_size, nb_zone;
  35   struct linear_data *data;
  36
  37   MOD_INC_USE_COUNT;
  38
  39   mddev->private=kmalloc (sizeof (struct linear_data), GFP_KERNEL);
  40   data=(struct linear_data *) mddev->private;
  41
  42   /*
  43      Find out the smallest device. This was previously done
  44      at registry time, but since it violates modularity,
  45      I moved it here... Any comment ? ;-)
  46    */
  47
  48   data->smallest=mddev->devices;
  49   for (i=1; i<mddev->nb_dev; i++)
  50     if (data->smallest->size > mddev->devices[i].size)
  51       data->smallest=mddev->devices+i;
  52
  53   nb_zone=data->nr_zones=
  54     md_size[minor]/data->smallest->size +
  55     (md_size[minor]%data->smallest->size ? 1 : 0);
  56
  57   data->hash_table=kmalloc (sizeof (struct linear_hash)*nb_zone, GFP_KERNEL);
  58
  59   size=mddev->devices[cur].size;
  60
  61   i=0;
  62   while (cur<mddev->nb_dev)
  63   {
  64     data->hash_table[i].dev0=mddev->devices+cur;
  65
  66     if (size>=data->smallest->size) /* If we completely fill the slot */
  67     {
  68       data->hash_table[i++].dev1=NULL;
  69       size-=data->smallest->size;
  70
  71       if (!size)
  72       {
  73         if (++cur==mddev->nb_dev) continue;
  74         size=mddev->devices[cur].size;
  75       }
  76
  77       continue;
  78     }
  79
  80     if (++cur==mddev->nb_dev) /* Last dev, set dev1 as NULL */
  81     {
  82       data->hash_table[i].dev1=NULL;
  83       continue;
  84     }
  85
  86     dev0_size=size;             /* Here, we use a 2nd dev to fill the slot */
  87     size=mddev->devices[cur].size;
  88     data->hash_table[i++].dev1=mddev->devices+cur;
  89     size-=(data->smallest->size - dev0_size);
  90   }
  91
  92   return 0;
  93 }
  94
  95 static int linear_stop (int minor, struct md_dev *mddev)
  96 {
  97   struct linear_data *data=(struct linear_data *) mddev->private;
  98
  99   kfree (data->hash_table);
 100   kfree (data);
 101
 102   MOD_DEC_USE_COUNT;
 103
 104   return 0;
 105 }
 106
 107
 108 static int linear_map (struct md_dev *mddev, kdev_t *rdev,
 109                        unsigned long *rsector, unsigned long size)
 110 {
 111   struct linear_data *data=(struct linear_data *) mddev->private;
 112   struct linear_hash *hash;
 113   struct real_dev *tmp_dev;
 114   long block;
 115
 116   block=*rsector >> 1;
 117   hash=data->hash_table+(block/data->smallest->size);
 118
 119   if (block >= (hash->dev0->size + hash->dev0->offset))
 120   {
 121     if (!hash->dev1)
 122     {
 123       printk ("linear_map : hash->dev1==NULL for block %ld\n", block);
 124       return (-1);
 125     }
 126
 127     tmp_dev=hash->dev1;
 128   }
 129   else
 130     tmp_dev=hash->dev0;
 131
 132   if (block >= (tmp_dev->size + tmp_dev->offset) || block < tmp_dev->offset)
 133     printk ("Block %ld out of bounds on dev %s size %d offset %d\n",
 134             block, kdevname(tmp_dev->dev), tmp_dev->size, tmp_dev->offset);
 135
 136   *rdev=tmp_dev->dev;
 137   *rsector=(block-(tmp_dev->offset)) << 1;
 138
 139   return (0);
 140 }
 141
 142 static int linear_status (char *page, int minor, struct md_dev *mddev)
 143 {
 144   int sz=0;
 145
 146 #undef MD_DEBUG
 147 #ifdef MD_DEBUG
 148   int j;
 149   struct linear_data *data=(struct linear_data *) mddev->private;
 150
 151   sz+=sprintf (page+sz, "      ");
 152   for (j=0; j<data->nr_zones; j++)
 153   {
 154     sz+=sprintf (page+sz, "[%s",
 155                  partition_name (data->hash_table[j].dev0->dev));
 156
 157     if (data->hash_table[j].dev1)
 158       sz+=sprintf (page+sz, "/%s] ",
 159                    partition_name(data->hash_table[j].dev1->dev));
 160     else
 161       sz+=sprintf (page+sz, "] ");
 162   }
 163
 164   sz+=sprintf (page+sz, "\n");
 165 #endif
 166   sz+=sprintf (page+sz, " %dk rounding", 1<<FACTOR_SHIFT(FACTOR(mddev)));
 167   return sz;
 168 }
 169
 170
 171 static struct md_personality linear_personality=
 172 {
 173   "linear",
 174   linear_map,
 175   NULL,
 176   NULL,
 177   linear_run,
 178   linear_stop,
 179   linear_status,
 180   NULL,                         /* no ioctls */
 181   0
 182 };
 183
 184
 185 #ifndef MODULE
 186
 187 __initfunc(void linear_init (void))
 188 {
 189   register_md_personality (LINEAR, &linear_personality);
 190 }
 191
 192 #else
 193
 194 int init_module (void)
 195 {
 196   return (register_md_personality (LINEAR, &linear_personality));
 197 }
 198
 199 void cleanup_module (void)
 200 {
 201   unregister_md_personality (LINEAR);
 202 }
 203
 204 #endif