drivers/s390/block/dasd_genhd.c

   1 /*
   2  * File...........: linux/drivers/s390/block/dasd_genhd.c
   3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   4  *                  Horst Hummel <Horst.Hummel@de.ibm.com>
   5  *                  Carsten Otte <Cotte@de.ibm.com>
   6  *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
   7  * Bugreports.to..: <Linux390@de.ibm.com>
   8  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
   9  *
  10  * gendisk related functions for the dasd driver.
  11  *
  12  */
  13
  14 #include <linux/interrupt.h>
  15 #include <linux/fs.h>
  16 #include <linux/blkpg.h>
  17
  18 #include <asm/uaccess.h>
  19
  20 /* This is ugly... */
  21 #define PRINTK_HEADER "dasd_gendisk:"
  22
  23 #include "dasd_int.h"
  24
  25 /*
  26  * Allocate and register gendisk structure for device.
  27  */
  28 int dasd_gendisk_alloc(struct dasd_block *block)
  29 {
  30         struct gendisk *gdp;
  31         struct dasd_device *base;
  32         int len;
  33
  34         /* Make sure the minor for this device exists. */
  35         base = block->base;
  36         if (base->devindex >= DASD_PER_MAJOR)
  37                 return -EBUSY;
  38
  39         gdp = alloc_disk(1 << DASD_PARTN_BITS);
  40         if (!gdp)
  41                 return -ENOMEM;
  42
  43         /* Initialize gendisk structure. */
  44         gdp->major = DASD_MAJOR;
  45         gdp->first_minor = base->devindex << DASD_PARTN_BITS;
  46         gdp->fops = &dasd_device_operations;
  47         gdp->driverfs_dev = &base->cdev->dev;
  48
  49         /*
  50          * Set device name.
  51          *   dasda - dasdz : 26 devices
  52          *   dasdaa - dasdzz : 676 devices, added up = 702
  53          *   dasdaaa - dasdzzz : 17576 devices, added up = 18278
  54          *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
  55          */
  56         len = sprintf(gdp->disk_name, "dasd");
  57         if (base->devindex > 25) {
  58                 if (base->devindex > 701) {
  59                         if (base->devindex > 18277)
  60                                 len += sprintf(gdp->disk_name + len, "%c",
  61                                                'a'+(((base->devindex-18278)
  62                                                      /17576)%26));
  63                         len += sprintf(gdp->disk_name + len, "%c",
  64                                        'a'+(((base->devindex-702)/676)%26));
  65                 }
  66                 len += sprintf(gdp->disk_name + len, "%c",
  67                                'a'+(((base->devindex-26)/26)%26));
  68         }
  69         len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));
  70
  71         if (block->base->features & DASD_FEATURE_READONLY)
  72                 set_disk_ro(gdp, 1);
  73         gdp->private_data = block;
  74         gdp->queue = block->request_queue;
  75         block->gdp = gdp;
  76         set_capacity(block->gdp, 0);
  77         add_disk(block->gdp);
  78         return 0;
  79 }
  80
  81 /*
  82  * Unregister and free gendisk structure for device.
  83  */
  84 void dasd_gendisk_free(struct dasd_block *block)
  85 {
  86         if (block->gdp) {
  87                 del_gendisk(block->gdp);
  88                 block->gdp->queue = NULL;
  89                 put_disk(block->gdp);
  90                 block->gdp = NULL;
  91         }
  92 }
  93
  94 /*
  95  * Trigger a partition detection.
  96  */
  97 int dasd_scan_partitions(struct dasd_block *block)
  98 {
  99         struct block_device *bdev;
 100
 101         bdev = bdget_disk(block->gdp, 0);
 102         if (!bdev || blkdev_get(bdev, FMODE_READ) < 0)
 103                 return -ENODEV;
 104         /*
 105          * See fs/partition/check.c:register_disk,rescan_partitions
 106          * Can't call rescan_partitions directly. Use ioctl.
 107          */
 108         ioctl_by_bdev(bdev, BLKRRPART, 0);
 109         /*
 110          * Since the matching blkdev_put call to the blkdev_get in
 111          * this function is not called before dasd_destroy_partitions
 112          * the offline open_count limit needs to be increased from
 113          * 0 to 1. This is done by setting device->bdev (see
 114          * dasd_generic_set_offline). As long as the partition
 115          * detection is running no offline should be allowed. That
 116          * is why the assignment to device->bdev is done AFTER
 117          * the BLKRRPART ioctl.
 118          */
 119         block->bdev = bdev;
 120         return 0;
 121 }
 122
 123 /*
 124  * Remove all inodes in the system for a device, delete the
 125  * partitions and make device unusable by setting its size to zero.
 126  */
 127 void dasd_destroy_partitions(struct dasd_block *block)
 128 {
 129         /* The two structs have 168/176 byte on 31/64 bit. */
 130         struct blkpg_partition bpart;
 131         struct blkpg_ioctl_arg barg;
 132         struct block_device *bdev;
 133
 134         /*
 135          * Get the bdev pointer from the device structure and clear
 136          * device->bdev to lower the offline open_count limit again.
 137          */
 138         bdev = block->bdev;
 139         block->bdev = NULL;
 140
 141         /*
 142          * See fs/partition/check.c:delete_partition
 143          * Can't call delete_partitions directly. Use ioctl.
 144          * The ioctl also does locking and invalidation.
 145          */
 146         memset(&bpart, 0, sizeof(struct blkpg_partition));
 147         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 148         barg.data = (void __force __user *) &bpart;
 149         barg.op = BLKPG_DEL_PARTITION;
 150         for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 151                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 152
 153         invalidate_partition(block->gdp, 0);
 154         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 155         blkdev_put(bdev, FMODE_READ);
 156         set_capacity(block->gdp, 0);
 157 }
 158
 159 int dasd_gendisk_init(void)
 160 {
 161         int rc;
 162
 163         /* Register to static dasd major 94 */
 164         rc = register_blkdev(DASD_MAJOR, "dasd");
 165         if (rc != 0) {
 166                 MESSAGE(KERN_WARNING,
 167                         "Couldn't register successfully to "
 168                         "major no %d", DASD_MAJOR);
 169                 return rc;
 170         }
 171         return 0;
 172 }
 173
 174 void dasd_gendisk_exit(void)
 175 {
 176         unregister_blkdev(DASD_MAJOR, "dasd");
 177 }