drivers/s390/block/dasd_genhd.c

   1 /*
   2  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
   3  *                  Horst Hummel <Horst.Hummel@de.ibm.com>
   4  *                  Carsten Otte <Cotte@de.ibm.com>
   5  *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
   6  * Bugreports.to..: <Linux390@de.ibm.com>
   7  * Copyright IBM Corp. 1999, 2001
   8  *
   9  * gendisk related functions for the dasd driver.
  10  *
  11  */
  12
  13 #define KMSG_COMPONENT "dasd"
  14
  15 #include <linux/interrupt.h>
  16 #include <linux/fs.h>
  17 #include <linux/blkpg.h>
  18
  19 #include <linux/uaccess.h>
  20
  21 /* This is ugly... */
  22 #define PRINTK_HEADER "dasd_gendisk:"
  23
  24 #include "dasd_int.h"
  25
  26 /*
  27  * Allocate and register gendisk structure for device.
  28  */
  29 int dasd_gendisk_alloc(struct dasd_block *block)
  30 {
  31         struct gendisk *gdp;
  32         struct dasd_device *base;
  33         int len;
  34
  35         /* Make sure the minor for this device exists. */
  36         base = block->base;
  37         if (base->devindex >= DASD_PER_MAJOR)
  38                 return -EBUSY;
  39
  40         gdp = alloc_disk(1 << DASD_PARTN_BITS);
  41         if (!gdp)
  42                 return -ENOMEM;
  43
  44         /* Initialize gendisk structure. */
  45         gdp->major = DASD_MAJOR;
  46         gdp->first_minor = base->devindex << DASD_PARTN_BITS;
  47         gdp->fops = &dasd_device_operations;
  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 (base->features & DASD_FEATURE_READONLY ||
  72             test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
  73                 set_disk_ro(gdp, 1);
  74         dasd_add_link_to_gendisk(gdp, base);
  75         gdp->queue = block->request_queue;
  76         block->gdp = gdp;
  77         set_capacity(block->gdp, 0);
  78         device_add_disk(&base->cdev->dev, block->gdp);
  79         return 0;
  80 }
  81
  82 /*
  83  * Unregister and free gendisk structure for device.
  84  */
  85 void dasd_gendisk_free(struct dasd_block *block)
  86 {
  87         if (block->gdp) {
  88                 del_gendisk(block->gdp);
  89                 block->gdp->private_data = NULL;
  90                 put_disk(block->gdp);
  91                 block->gdp = NULL;
  92         }
  93 }
  94
  95 /*
  96  * Trigger a partition detection.
  97  */
  98 int dasd_scan_partitions(struct dasd_block *block)
  99 {
 100         struct block_device *bdev;
 101         int rc;
 102
 103         bdev = bdget_disk(block->gdp, 0);
 104         if (!bdev) {
 105                 DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
 106                               "scan partitions error, bdget returned NULL");
 107                 return -ENODEV;
 108         }
 109
 110         rc = blkdev_get(bdev, FMODE_READ, NULL);
 111         if (rc < 0) {
 112                 DBF_DEV_EVENT(DBF_ERR, block->base,
 113                               "scan partitions error, blkdev_get returned %d",
 114                               rc);
 115                 return -ENODEV;
 116         }
 117
 118         rc = blkdev_reread_part(bdev);
 119         if (rc)
 120                 DBF_DEV_EVENT(DBF_ERR, block->base,
 121                                 "scan partitions error, rc %d", rc);
 122
 123         /*
 124          * Since the matching blkdev_put call to the blkdev_get in
 125          * this function is not called before dasd_destroy_partitions
 126          * the offline open_count limit needs to be increased from
 127          * 0 to 1. This is done by setting device->bdev (see
 128          * dasd_generic_set_offline). As long as the partition
 129          * detection is running no offline should be allowed. That
 130          * is why the assignment to device->bdev is done AFTER
 131          * the BLKRRPART ioctl.
 132          */
 133         block->bdev = bdev;
 134         return 0;
 135 }
 136
 137 /*
 138  * Remove all inodes in the system for a device, delete the
 139  * partitions and make device unusable by setting its size to zero.
 140  */
 141 void dasd_destroy_partitions(struct dasd_block *block)
 142 {
 143         /* The two structs have 168/176 byte on 31/64 bit. */
 144         struct blkpg_partition bpart;
 145         struct blkpg_ioctl_arg barg;
 146         struct block_device *bdev;
 147
 148         /*
 149          * Get the bdev pointer from the device structure and clear
 150          * device->bdev to lower the offline open_count limit again.
 151          */
 152         bdev = block->bdev;
 153         block->bdev = NULL;
 154
 155         /*
 156          * See fs/partition/check.c:delete_partition
 157          * Can't call delete_partitions directly. Use ioctl.
 158          * The ioctl also does locking and invalidation.
 159          */
 160         memset(&bpart, 0, sizeof(struct blkpg_partition));
 161         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 162         barg.data = (void __force __user *) &bpart;
 163         barg.op = BLKPG_DEL_PARTITION;
 164         for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 165                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 166
 167         invalidate_partition(block->gdp, 0);
 168         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 169         blkdev_put(bdev, FMODE_READ);
 170         set_capacity(block->gdp, 0);
 171 }
 172
 173 int dasd_gendisk_init(void)
 174 {
 175         int rc;
 176
 177         /* Register to static dasd major 94 */
 178         rc = register_blkdev(DASD_MAJOR, "dasd");
 179         if (rc != 0) {
 180                 pr_warn("Registering the device driver with major number %d failed\n",
 181                         DASD_MAJOR);
 182                 return rc;
 183         }
 184         return 0;
 185 }
 186
 187 void dasd_gendisk_exit(void)
 188 {
 189         unregister_blkdev(DASD_MAJOR, "dasd");
 190 }