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/config.h>
  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
  30 dasd_gendisk_alloc(struct dasd_device *device)
  31 {
  32         struct gendisk *gdp;
  33         int len;
  34
  35         /* Make sure the minor for this device exists. */
  36         if (device->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 = device->devindex << DASD_PARTN_BITS;
  46         gdp->fops = &dasd_device_operations;
  47         gdp->driverfs_dev = &device->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 (device->devindex > 25) {
  58                 if (device->devindex > 701) {
  59                         if (device->devindex > 18277)
  60                                 len += sprintf(gdp->disk_name + len, "%c",
  61                                                'a'+(((device->devindex-18278)
  62                                                      /17576)%26));
  63                         len += sprintf(gdp->disk_name + len, "%c",
  64                                        'a'+(((device->devindex-702)/676)%26));
  65                 }
  66                 len += sprintf(gdp->disk_name + len, "%c",
  67                                'a'+(((device->devindex-26)/26)%26));
  68         }
  69         len += sprintf(gdp->disk_name + len, "%c", 'a'+(device->devindex%26));
  70
  71         sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
  72
  73         if (device->features & DASD_FEATURE_READONLY)
  74                 set_disk_ro(gdp, 1);
  75         gdp->private_data = device;
  76         gdp->queue = device->request_queue;
  77         device->gdp = gdp;
  78         set_capacity(device->gdp, 0);
  79         add_disk(device->gdp);
  80         return 0;
  81 }
  82
  83 /*
  84  * Unregister and free gendisk structure for device.
  85  */
  86 void
  87 dasd_gendisk_free(struct dasd_device *device)
  88 {
  89         del_gendisk(device->gdp);
  90         device->gdp->queue = 0;
  91         put_disk(device->gdp);
  92         device->gdp = 0;
  93 }
  94
  95 /*
  96  * Trigger a partition detection.
  97  */
  98 int
  99 dasd_scan_partitions(struct dasd_device * device)
 100 {
 101         struct block_device *bdev;
 102
 103         bdev = bdget_disk(device->gdp, 0);
 104         if (!bdev || blkdev_get(bdev, FMODE_READ, 1) < 0)
 105                 return -ENODEV;
 106         /*
 107          * See fs/partition/check.c:register_disk,rescan_partitions
 108          * Can't call rescan_partitions directly. Use ioctl.
 109          */
 110         ioctl_by_bdev(bdev, BLKRRPART, 0);
 111         /*
 112          * Since the matching blkdev_put call to the blkdev_get in
 113          * this function is not called before dasd_destroy_partitions
 114          * the offline open_count limit needs to be increased from
 115          * 0 to 1. This is done by setting device->bdev (see
 116          * dasd_generic_set_offline). As long as the partition
 117          * detection is running no offline should be allowed. That
 118          * is why the assignment to device->bdev is done AFTER
 119          * the BLKRRPART ioctl.
 120          */
 121         device->bdev = bdev;
 122         return 0;
 123 }
 124
 125 /*
 126  * Remove all inodes in the system for a device, delete the
 127  * partitions and make device unusable by setting its size to zero.
 128  */
 129 void
 130 dasd_destroy_partitions(struct dasd_device * device)
 131 {
 132         /* The two structs have 168/176 byte on 31/64 bit. */
 133         struct blkpg_partition bpart;
 134         struct blkpg_ioctl_arg barg;
 135         struct block_device *bdev;
 136
 137         /*
 138          * Get the bdev pointer from the device structure and clear
 139          * device->bdev to lower the offline open_count limit again.
 140          */
 141         bdev = device->bdev;
 142         device->bdev = 0;
 143
 144         /*
 145          * See fs/partition/check.c:delete_partition
 146          * Can't call delete_partitions directly. Use ioctl.
 147          * The ioctl also does locking and invalidation.
 148          */
 149         memset(&bpart, 0, sizeof(struct blkpg_partition));
 150         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 151         barg.data = &bpart;
 152         barg.op = BLKPG_DEL_PARTITION;
 153         for (bpart.pno = device->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 154                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 155
 156         invalidate_partition(device->gdp, 0);
 157         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 158         blkdev_put(bdev);
 159         set_capacity(device->gdp, 0);
 160 }
 161
 162 int
 163 dasd_gendisk_init(void)
 164 {
 165         int rc;
 166
 167         /* Register to static dasd major 94 */
 168         rc = register_blkdev(DASD_MAJOR, "dasd");
 169         if (rc != 0) {
 170                 MESSAGE(KERN_WARNING,
 171                         "Couldn't register successfully to "
 172                         "major no %d", DASD_MAJOR);
 173                 return rc;
 174         }
 175         return 0;
 176 }
 177
 178 void
 179 dasd_gendisk_exit(void)
 180 {
 181         unregister_blkdev(DASD_MAJOR, "dasd");
 182 }