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 <asm/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         gdp->driverfs_dev = &base->cdev->dev;
  49
  50         /*
  51          * Set device name.
  52          *   dasda - dasdz : 26 devices
  53          *   dasdaa - dasdzz : 676 devices, added up = 702
  54          *   dasdaaa - dasdzzz : 17576 devices, added up = 18278
  55          *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
  56          */
  57         len = sprintf(gdp->disk_name, "dasd");
  58         if (base->devindex > 25) {
  59                 if (base->devindex > 701) {
  60                         if (base->devindex > 18277)
  61                                 len += sprintf(gdp->disk_name + len, "%c",
  62                                                'a'+(((base->devindex-18278)
  63                                                      /17576)%26));
  64                         len += sprintf(gdp->disk_name + len, "%c",
  65                                        'a'+(((base->devindex-702)/676)%26));
  66                 }
  67                 len += sprintf(gdp->disk_name + len, "%c",
  68                                'a'+(((base->devindex-26)/26)%26));
  69         }
  70         len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));
  71
  72         if (base->features & DASD_FEATURE_READONLY ||
  73             test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
  74                 set_disk_ro(gdp, 1);
  75         dasd_add_link_to_gendisk(gdp, base);
  76         gdp->queue = block->request_queue;
  77         block->gdp = gdp;
  78         set_capacity(block->gdp, 0);
  79         add_disk(block->gdp);
  80         return 0;
  81 }
  82
  83 /*
  84  * Unregister and free gendisk structure for device.
  85  */
  86 void dasd_gendisk_free(struct dasd_block *block)
  87 {
  88         if (block->gdp) {
  89                 del_gendisk(block->gdp);
  90                 block->gdp->private_data = NULL;
  91                 put_disk(block->gdp);
  92                 block->gdp = NULL;
  93         }
  94 }
  95
  96 /*
  97  * Trigger a partition detection.
  98  */
  99 int dasd_scan_partitions(struct dasd_block *block)
 100 {
 101         struct block_device *bdev;
 102         int retry, rc;
 103
 104         retry = 5;
 105         bdev = bdget_disk(block->gdp, 0);
 106         if (!bdev) {
 107                 DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
 108                               "scan partitions error, bdget returned NULL");
 109                 return -ENODEV;
 110         }
 111
 112         rc = blkdev_get(bdev, FMODE_READ, NULL);
 113         if (rc < 0) {
 114                 DBF_DEV_EVENT(DBF_ERR, block->base,
 115                               "scan partitions error, blkdev_get returned %d",
 116                               rc);
 117                 return -ENODEV;
 118         }
 119         /*
 120          * See fs/partition/check.c:register_disk,rescan_partitions
 121          * Can't call rescan_partitions directly. Use ioctl.
 122          */
 123         rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
 124         while (rc == -EBUSY && retry > 0) {
 125                 schedule();
 126                 rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
 127                 retry--;
 128                 DBF_DEV_EVENT(DBF_ERR, block->base,
 129                               "scan partitions error, retry %d rc %d",
 130                               retry, rc);
 131         }
 132
 133         /*
 134          * Since the matching blkdev_put call to the blkdev_get in
 135          * this function is not called before dasd_destroy_partitions
 136          * the offline open_count limit needs to be increased from
 137          * 0 to 1. This is done by setting device->bdev (see
 138          * dasd_generic_set_offline). As long as the partition
 139          * detection is running no offline should be allowed. That
 140          * is why the assignment to device->bdev is done AFTER
 141          * the BLKRRPART ioctl.
 142          */
 143         block->bdev = bdev;
 144         return 0;
 145 }
 146
 147 /*
 148  * Remove all inodes in the system for a device, delete the
 149  * partitions and make device unusable by setting its size to zero.
 150  */
 151 void dasd_destroy_partitions(struct dasd_block *block)
 152 {
 153         /* The two structs have 168/176 byte on 31/64 bit. */
 154         struct blkpg_partition bpart;
 155         struct blkpg_ioctl_arg barg;
 156         struct block_device *bdev;
 157
 158         /*
 159          * Get the bdev pointer from the device structure and clear
 160          * device->bdev to lower the offline open_count limit again.
 161          */
 162         bdev = block->bdev;
 163         block->bdev = NULL;
 164
 165         /*
 166          * See fs/partition/check.c:delete_partition
 167          * Can't call delete_partitions directly. Use ioctl.
 168          * The ioctl also does locking and invalidation.
 169          */
 170         memset(&bpart, 0, sizeof(struct blkpg_partition));
 171         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 172         barg.data = (void __force __user *) &bpart;
 173         barg.op = BLKPG_DEL_PARTITION;
 174         for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 175                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 176
 177         invalidate_partition(block->gdp, 0);
 178         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 179         blkdev_put(bdev, FMODE_READ);
 180         set_capacity(block->gdp, 0);
 181 }
 182
 183 int dasd_gendisk_init(void)
 184 {
 185         int rc;
 186
 187         /* Register to static dasd major 94 */
 188         rc = register_blkdev(DASD_MAJOR, "dasd");
 189         if (rc != 0) {
 190                 pr_warning("Registering the device driver with major number "
 191                            "%d failed\n", DASD_MAJOR);
 192                 return rc;
 193         }
 194         return 0;
 195 }
 196
 197 void dasd_gendisk_exit(void)
 198 {
 199         unregister_blkdev(DASD_MAJOR, "dasd");
 200 }