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