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/interrupt.h>
  15 #include <linux/fs.h>
  16 #include <linux/blkpg.h>
  17
  18 #include <asm/uaccess.h>
  19
  20 /* This is ugly... */
  21 #define PRINTK_HEADER "dasd_gendisk:"
  22
  23 #include "dasd_int.h"
  24
  25 /*
  26  * Allocate and register gendisk structure for device.
  27  */
  28 int
  29 dasd_gendisk_alloc(struct dasd_device *device)
  30 {
  31         struct gendisk *gdp;
  32         int len;
  33
  34         /* Make sure the minor for this device exists. */
  35         if (device->devindex >= DASD_PER_MAJOR)
  36                 return -EBUSY;
  37
  38         gdp = alloc_disk(1 << DASD_PARTN_BITS);
  39         if (!gdp)
  40                 return -ENOMEM;
  41
  42         /* Initialize gendisk structure. */
  43         gdp->major = DASD_MAJOR;
  44         gdp->first_minor = device->devindex << DASD_PARTN_BITS;
  45         gdp->fops = &dasd_device_operations;
  46         gdp->driverfs_dev = &device->cdev->dev;
  47
  48         /*
  49          * Set device name.
  50          *   dasda - dasdz : 26 devices
  51          *   dasdaa - dasdzz : 676 devices, added up = 702
  52          *   dasdaaa - dasdzzz : 17576 devices, added up = 18278
  53          *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
  54          */
  55         len = sprintf(gdp->disk_name, "dasd");
  56         if (device->devindex > 25) {
  57                 if (device->devindex > 701) {
  58                         if (device->devindex > 18277)
  59                                 len += sprintf(gdp->disk_name + len, "%c",
  60                                                'a'+(((device->devindex-18278)
  61                                                      /17576)%26));
  62                         len += sprintf(gdp->disk_name + len, "%c",
  63                                        'a'+(((device->devindex-702)/676)%26));
  64                 }
  65                 len += sprintf(gdp->disk_name + len, "%c",
  66                                'a'+(((device->devindex-26)/26)%26));
  67         }
  68         len += sprintf(gdp->disk_name + len, "%c", 'a'+(device->devindex%26));
  69
  70         if (device->features & DASD_FEATURE_READONLY)
  71                 set_disk_ro(gdp, 1);
  72         gdp->private_data = device;
  73         gdp->queue = device->request_queue;
  74         device->gdp = gdp;
  75         set_capacity(device->gdp, 0);
  76         add_disk(device->gdp);
  77         return 0;
  78 }
  79
  80 /*
  81  * Unregister and free gendisk structure for device.
  82  */
  83 void
  84 dasd_gendisk_free(struct dasd_device *device)
  85 {
  86         if (device->gdp) {
  87                 del_gendisk(device->gdp);
  88                 device->gdp->queue = NULL;
  89                 put_disk(device->gdp);
  90                 device->gdp = NULL;
  91         }
  92 }
  93
  94 /*
  95  * Trigger a partition detection.
  96  */
  97 int
  98 dasd_scan_partitions(struct dasd_device * device)
  99 {
 100         struct block_device *bdev;
 101
 102         bdev = bdget_disk(device->gdp, 0);
 103         if (!bdev || blkdev_get(bdev, FMODE_READ, 1) < 0)
 104                 return -ENODEV;
 105         /*
 106          * See fs/partition/check.c:register_disk,rescan_partitions
 107          * Can't call rescan_partitions directly. Use ioctl.
 108          */
 109         ioctl_by_bdev(bdev, BLKRRPART, 0);
 110         /*
 111          * Since the matching blkdev_put call to the blkdev_get in
 112          * this function is not called before dasd_destroy_partitions
 113          * the offline open_count limit needs to be increased from
 114          * 0 to 1. This is done by setting device->bdev (see
 115          * dasd_generic_set_offline). As long as the partition
 116          * detection is running no offline should be allowed. That
 117          * is why the assignment to device->bdev is done AFTER
 118          * the BLKRRPART ioctl.
 119          */
 120         device->bdev = bdev;
 121         return 0;
 122 }
 123
 124 /*
 125  * Remove all inodes in the system for a device, delete the
 126  * partitions and make device unusable by setting its size to zero.
 127  */
 128 void
 129 dasd_destroy_partitions(struct dasd_device * device)
 130 {
 131         /* The two structs have 168/176 byte on 31/64 bit. */
 132         struct blkpg_partition bpart;
 133         struct blkpg_ioctl_arg barg;
 134         struct block_device *bdev;
 135
 136         /*
 137          * Get the bdev pointer from the device structure and clear
 138          * device->bdev to lower the offline open_count limit again.
 139          */
 140         bdev = device->bdev;
 141         device->bdev = NULL;
 142
 143         /*
 144          * See fs/partition/check.c:delete_partition
 145          * Can't call delete_partitions directly. Use ioctl.
 146          * The ioctl also does locking and invalidation.
 147          */
 148         memset(&bpart, 0, sizeof(struct blkpg_partition));
 149         memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
 150         barg.data = (void __force __user *) &bpart;
 151         barg.op = BLKPG_DEL_PARTITION;
 152         for (bpart.pno = device->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
 153                 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
 154
 155         invalidate_partition(device->gdp, 0);
 156         /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 157         blkdev_put(bdev);
 158         set_capacity(device->gdp, 0);
 159 }
 160
 161 int
 162 dasd_gendisk_init(void)
 163 {
 164         int rc;
 165
 166         /* Register to static dasd major 94 */
 167         rc = register_blkdev(DASD_MAJOR, "dasd");
 168         if (rc != 0) {
 169                 MESSAGE(KERN_WARNING,
 170                         "Couldn't register successfully to "
 171                         "major no %d", DASD_MAJOR);
 172                 return rc;
 173         }
 174         return 0;
 175 }
 176
 177 void
 178 dasd_gendisk_exit(void)
 179 {
 180         unregister_blkdev(DASD_MAJOR, "dasd");
 181 }