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: 1.50 $
  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, feature_ro;
  35
  36         /* Make sure the minor for this device exists. */
  37         if (device->devindex >= DASD_PER_MAJOR)
  38                 return -EBUSY;
  39
  40         feature_ro = dasd_get_feature(device->cdev, DASD_FEATURE_READONLY);
  41         if (feature_ro < 0)
  42                 return feature_ro;
  43
  44         gdp = alloc_disk(1 << DASD_PARTN_BITS);
  45         if (!gdp)
  46                 return -ENOMEM;
  47
  48         /* Initialize gendisk structure. */
  49         gdp->major = DASD_MAJOR;
  50         gdp->first_minor = device->devindex << DASD_PARTN_BITS;
  51         gdp->fops = &dasd_device_operations;
  52         gdp->driverfs_dev = &device->cdev->dev;
  53
  54         /*
  55          * Set device name.
  56          *   dasda - dasdz : 26 devices
  57          *   dasdaa - dasdzz : 676 devices, added up = 702
  58          *   dasdaaa - dasdzzz : 17576 devices, added up = 18278
  59          *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
  60          */
  61         len = sprintf(gdp->disk_name, "dasd");
  62         if (device->devindex > 25) {
  63                 if (device->devindex > 701) {
  64                         if (device->devindex > 18277)
  65                                 len += sprintf(gdp->disk_name + len, "%c",
  66                                                'a'+(((device->devindex-18278)
  67                                                      /17576)%26));
  68                         len += sprintf(gdp->disk_name + len, "%c",
  69                                        'a'+(((device->devindex-702)/676)%26));
  70                 }
  71                 len += sprintf(gdp->disk_name + len, "%c",
  72                                'a'+(((device->devindex-26)/26)%26));
  73         }
  74         len += sprintf(gdp->disk_name + len, "%c", 'a'+(device->devindex%26));
  75
  76         sprintf(gdp->devfs_name, "dasd/%s", device->cdev->dev.bus_id);
  77
  78         if (feature_ro)
  79                 set_disk_ro(gdp, 1);
  80         gdp->private_data = device;
  81         gdp->queue = device->request_queue;
  82         device->gdp = gdp;
  83         set_capacity(device->gdp, 0);
  84         add_disk(device->gdp);
  85         return 0;
  86 }
  87
  88 /*
  89  * Unregister and free gendisk structure for device.
  90  */
  91 void
  92 dasd_gendisk_free(struct dasd_device *device)
  93 {
  94         del_gendisk(device->gdp);
  95         device->gdp->queue = 0;
  96         put_disk(device->gdp);
  97         device->gdp = 0;
  98 }
  99
 100 /*
 101  * Trigger a partition detection.
 102  */
 103 int
 104 dasd_scan_partitions(struct dasd_device * device)
 105 {
 106         struct block_device *bdev;
 107
 108         /* Make the disk known. */
 109         set_capacity(device->gdp, device->blocks << device->s2b_shift);
 110         bdev = bdget_disk(device->gdp, 0);
 111         if (!bdev || blkdev_get(bdev, FMODE_READ, 1) < 0)
 112                 return -ENODEV;
 113         /*
 114          * See fs/partition/check.c:register_disk,rescan_partitions
 115          * Can't call rescan_partitions directly. Use ioctl.
 116          */
 117         ioctl_by_bdev(bdev, BLKRRPART, 0);
 118         /*
 119          * Since the matching blkdev_put call to the blkdev_get in
 120          * this function is not called before dasd_destroy_partitions
 121          * the offline open_count limit needs to be increased from
 122          * 0 to 1. This is done by setting device->bdev (see
 123          * dasd_generic_set_offline). As long as the partition
 124          * detection is running no offline should be allowed. That
 125          * is why the assignment to device->bdev is done AFTER
 126          * the BLKRRPART ioctl.
 127          */
 128         device->bdev = bdev;
 129         return 0;
 130 }
 131
 132 /*
 133  * Remove all inodes in the system for a device, delete the
 134  * partitions and make device unusable by setting its size to zero.
 135  */
 136 void
 137 dasd_destroy_partitions(struct dasd_device * device)
 138 {
 139         /* The two structs have 168/176 byte on 31/64 bit. */
 140         struct blkpg_partition bpart;
 141         struct blkpg_ioctl_arg barg;
 142         struct block_device *bdev;
 143
 144         /*
 145          * Get the bdev pointer from the device structure and clear
 146          * device->bdev to lower the offline open_count limit again.
 147          */
 148         bdev = device->bdev;
 149         device->bdev = 0;
 150
 151         /*
 152          * See fs/partition/check.c:delete_partition
 153          * Can't call delete_partitions directly. Use ioctl.
 154          * The ioctl also does locking and invalidation.
 155          */
 156         memset(&bpart, 0, sizeof(struct blkpg_partition));
 157         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 158         barg.data = &bpart;
 159         barg.op = BLKPG_DEL_PARTITION;
 160         for (bpart.pno = device->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 161                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 162
 163         invalidate_partition(device->gdp, 0);
 164         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 165         blkdev_put(bdev);
 166         set_capacity(device->gdp, 0);
 167 }
 168
 169 int
 170 dasd_gendisk_init(void)
 171 {
 172         int rc;
 173
 174         /* Register to static dasd major 94 */
 175         rc = register_blkdev(DASD_MAJOR, "dasd");
 176         if (rc != 0) {
 177                 MESSAGE(KERN_WARNING,
 178                         "Couldn't register successfully to "
 179                         "major no %d", DASD_MAJOR);
 180                 return rc;
 181         }
 182         return 0;
 183 }
 184
 185 void
 186 dasd_gendisk_exit(void)
 187 {
 188         unregister_blkdev(DASD_MAJOR, "dasd");
 189 }