diff options
Diffstat (limited to 'drivers/s390/block/dasd_genhd.c')
| -rw-r--r-- | drivers/s390/block/dasd_genhd.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c new file mode 100644 index 000000000..a9698fba9 --- /dev/null +++ b/drivers/s390/block/dasd_genhd.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com> + * Horst Hummel <Horst.Hummel@de.ibm.com> + * Carsten Otte <Cotte@de.ibm.com> + * Martin Schwidefsky <schwidefsky@de.ibm.com> + * Bugreports.to..: <Linux390@de.ibm.com> + * Copyright IBM Corp. 1999, 2001 + * + * gendisk related functions for the dasd driver. + * + */ + +#define KMSG_COMPONENT "dasd" + +#include <linux/interrupt.h> +#include <linux/fs.h> +#include <linux/blkpg.h> + +#include <linux/uaccess.h> + +/* This is ugly... */ +#define PRINTK_HEADER "dasd_gendisk:" + +#include "dasd_int.h" + +/* + * Allocate and register gendisk structure for device. + */ +int dasd_gendisk_alloc(struct dasd_block *block) +{ + struct gendisk *gdp; + struct dasd_device *base; + int len; + + /* Make sure the minor for this device exists. */ + base = block->base; + if (base->devindex >= DASD_PER_MAJOR) + return -EBUSY; + + gdp = alloc_disk(1 << DASD_PARTN_BITS); + if (!gdp) + return -ENOMEM; + + /* Initialize gendisk structure. */ + gdp->major = DASD_MAJOR; + gdp->first_minor = base->devindex << DASD_PARTN_BITS; + gdp->fops = &dasd_device_operations; + + /* + * Set device name. + * dasda - dasdz : 26 devices + * dasdaa - dasdzz : 676 devices, added up = 702 + * dasdaaa - dasdzzz : 17576 devices, added up = 18278 + * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252 + */ + len = sprintf(gdp->disk_name, "dasd"); + if (base->devindex > 25) { + if (base->devindex > 701) { + if (base->devindex > 18277) + len += sprintf(gdp->disk_name + len, "%c", + 'a'+(((base->devindex-18278) + /17576)%26)); + len += sprintf(gdp->disk_name + len, "%c", + 'a'+(((base->devindex-702)/676)%26)); + } + len += sprintf(gdp->disk_name + len, "%c", + 'a'+(((base->devindex-26)/26)%26)); + } + len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26)); + + if (base->features & DASD_FEATURE_READONLY || + test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) + set_disk_ro(gdp, 1); + dasd_add_link_to_gendisk(gdp, base); + gdp->queue = block->request_queue; + block->gdp = gdp; + set_capacity(block->gdp, 0); + device_add_disk(&base->cdev->dev, block->gdp, NULL); + return 0; +} + +/* + * Unregister and free gendisk structure for device. + */ +void dasd_gendisk_free(struct dasd_block *block) +{ + if (block->gdp) { + del_gendisk(block->gdp); + block->gdp->private_data = NULL; + put_disk(block->gdp); + block->gdp = NULL; + } +} + +/* + * Trigger a partition detection. + */ +int dasd_scan_partitions(struct dasd_block *block) +{ + struct block_device *bdev; + int rc; + + bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL); + if (IS_ERR(bdev)) { + DBF_DEV_EVENT(DBF_ERR, block->base, + "scan partitions error, blkdev_get returned %ld", + PTR_ERR(bdev)); + return -ENODEV; + } + + mutex_lock(&bdev->bd_mutex); + rc = bdev_disk_changed(bdev, false); + mutex_unlock(&bdev->bd_mutex); + if (rc) + DBF_DEV_EVENT(DBF_ERR, block->base, + "scan partitions error, rc %d", rc); + + /* + * Since the matching blkdev_put call to the blkdev_get in + * this function is not called before dasd_destroy_partitions + * the offline open_count limit needs to be increased from + * 0 to 1. This is done by setting device->bdev (see + * dasd_generic_set_offline). As long as the partition + * detection is running no offline should be allowed. That + * is why the assignment to device->bdev is done AFTER + * the BLKRRPART ioctl. + */ + block->bdev = bdev; + return 0; +} + +/* + * Remove all inodes in the system for a device, delete the + * partitions and make device unusable by setting its size to zero. + */ +void dasd_destroy_partitions(struct dasd_block *block) +{ + struct block_device *bdev; + + /* + * Get the bdev pointer from the device structure and clear + * device->bdev to lower the offline open_count limit again. + */ + bdev = block->bdev; + block->bdev = NULL; + + mutex_lock(&bdev->bd_mutex); + blk_drop_partitions(bdev); + mutex_unlock(&bdev->bd_mutex); + + /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */ + blkdev_put(bdev, FMODE_READ); + set_capacity(block->gdp, 0); +} + +int dasd_gendisk_init(void) +{ + int rc; + + /* Register to static dasd major 94 */ + rc = register_blkdev(DASD_MAJOR, "dasd"); + if (rc != 0) { + pr_warn("Registering the device driver with major number %d failed\n", + DASD_MAJOR); + return rc; + } + return 0; +} + +void dasd_gendisk_exit(void) +{ + unregister_blkdev(DASD_MAJOR, "dasd"); +} |