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  * $Revision: 1.51 $
  13  */
  14
  15 #include <linux/config.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/fs.h>
  18 #include <linux/blkpg.h>
  19
  20 #include <asm/uaccess.h>
  21
  22 /* This is ugly... */
  23 #define PRINTK_HEADER "dasd_gendisk:"
  24
  25 #include "dasd_int.h"
  26
  27 /*
  28  * Allocate and register gendisk structure for device.
  29  */
  30 int
  31 dasd_gendisk_alloc(struct dasd_device *device)
  32 {
  33         struct gendisk *gdp;
  34         int len;
  35
  36         /* Make sure the minor for this device exists. */
  37         if (device->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 = device->devindex << DASD_PARTN_BITS;
  47         gdp->fops = &dasd_device_operations;
  48         gdp->driverfs_dev = &device->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 (device->devindex > 25) {
  59                 if (device->devindex > 701) {
  60                         if (device->devindex > 18277)
  61                                 len += sprintf(gdp->disk_name + len, "%c",
  62                                                'a'+(((device->devindex-18278)
  63                                                      /17576)%26));
  64                         len += sprintf(gdp->disk_name + len, "%c",
  65                                        'a'+(((device->devindex-702)/676)%26));
  66                 }
  67                 len += sprintf(gdp->disk_name + len, "%c",
  68                                'a'+(((device->devindex-26)/26)%26));
  69         }
  70         len += sprintf(gdp->disk_name + len, "%c", 'a'+(device->devindex%26));
  71
  72         sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
  73
  74         if (device->features & DASD_FEATURE_READONLY)
  75                 set_disk_ro(gdp, 1);
  76         gdp->private_data = device;
  77         gdp->queue = device->request_queue;
  78         device->gdp = gdp;
  79         set_capacity(device->gdp, 0);
  80         add_disk(device->gdp);
  81         return 0;
  82 }
  83
  84 /*
  85  * Unregister and free gendisk structure for device.
  86  */
  87 void
  88 dasd_gendisk_free(struct dasd_device *device)
  89 {
  90         del_gendisk(device->gdp);
  91         device->gdp->queue = 0;
  92         put_disk(device->gdp);
  93         device->gdp = 0;
  94 }
  95
  96 /*
  97  * Trigger a partition detection.
  98  */
  99 int
 100 dasd_scan_partitions(struct dasd_device * device)
 101 {
 102         struct block_device *bdev;
 103
 104         /* Make the disk known. */
 105         set_capacity(device->gdp, device->blocks << device->s2b_shift);
 106         bdev = bdget_disk(device->gdp, 0);
 107         if (!bdev || blkdev_get(bdev, FMODE_READ, 1) < 0)
 108                 return -ENODEV;
 109         /*
 110          * See fs/partition/check.c:register_disk,rescan_partitions
 111          * Can't call rescan_partitions directly. Use ioctl.
 112          */
 113         ioctl_by_bdev(bdev, BLKRRPART, 0);
 114         /*
 115          * Since the matching blkdev_put call to the blkdev_get in
 116          * this function is not called before dasd_destroy_partitions
 117          * the offline open_count limit needs to be increased from
 118          * 0 to 1. This is done by setting device->bdev (see
 119          * dasd_generic_set_offline). As long as the partition
 120          * detection is running no offline should be allowed. That
 121          * is why the assignment to device->bdev is done AFTER
 122          * the BLKRRPART ioctl.
 123          */
 124         device->bdev = bdev;
 125         return 0;
 126 }
 127
 128 /*
 129  * Remove all inodes in the system for a device, delete the
 130  * partitions and make device unusable by setting its size to zero.
 131  */
 132 void
 133 dasd_destroy_partitions(struct dasd_device * device)
 134 {
 135         /* The two structs have 168/176 byte on 31/64 bit. */
 136         struct blkpg_partition bpart;
 137         struct blkpg_ioctl_arg barg;
 138         struct block_device *bdev;
 139
 140         /*
 141          * Get the bdev pointer from the device structure and clear
 142          * device->bdev to lower the offline open_count limit again.
 143          */
 144         bdev = device->bdev;
 145         device->bdev = 0;
 146
 147         /*
 148          * See fs/partition/check.c:delete_partition
 149          * Can't call delete_partitions directly. Use ioctl.
 150          * The ioctl also does locking and invalidation.
 151          */
 152         memset(&bpart, 0, sizeof(struct blkpg_partition));
 153         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 154         barg.data = &bpart;
 155         barg.op = BLKPG_DEL_PARTITION;
 156         for (bpart.pno = device->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 157                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 158
 159         invalidate_partition(device->gdp, 0);
 160         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 161         blkdev_put(bdev);
 162         set_capacity(device->gdp, 0);
 163 }
 164
 165 int
 166 dasd_gendisk_init(void)
 167 {
 168         int rc;
 169
 170         /* Register to static dasd major 94 */
 171         rc = register_blkdev(DASD_MAJOR, "dasd");
 172         if (rc != 0) {
 173                 MESSAGE(KERN_WARNING,
 174                         "Couldn't register successfully to "
 175                         "major no %d", DASD_MAJOR);
 176                 return rc;
 177         }
 178         return 0;
 179 }
 180
 181 void
 182 dasd_gendisk_exit(void)
 183 {
 184         unregister_blkdev(DASD_MAJOR, "dasd");
 185 }