// SPDX-License-Identifier: GPL-2.0
/*
* Author(s)......: Holger Smolinski <[email protected]>
* Horst Hummel <[email protected]>
* Carsten Otte <[email protected]>
* Martin Schwidefsky <[email protected]>
* Bugreports.to..: <[email protected]>
* Copyright IBM Corp. 1999, 2001
*
* gendisk related functions for the dasd driver.
*
*/
#include <linux/interrupt.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/blkpg.h>
#include <linux/uaccess.h>
#include "dasd_int.h"
static unsigned int queue_depth = 32;
static unsigned int nr_hw_queues = 4;
module_param(queue_depth, uint, 0444);
MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
module_param(nr_hw_queues, uint, 0444);
MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");
/*
* Allocate and register gendisk structure for device.
*/
int dasd_gendisk_alloc(struct dasd_block *block)
{
struct queue_limits lim = {
/*
* With page sized segments, each segment can be translated into
* one idaw/tidaw.
*/
.max_segment_size = PAGE_SIZE,
.seg_boundary_mask = PAGE_SIZE - 1,
.dma_alignment = PAGE_SIZE - 1,
.max_segments = USHRT_MAX,
};
struct gendisk *gdp;
struct dasd_device *base;
int len, rc;
/* Make sure the minor for this device exists. */
base = block->base;
if (base->devindex >= DASD_PER_MAJOR)
return -EBUSY;
block->tag_set.ops = &dasd_mq_ops;
block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);
block->tag_set.nr_hw_queues = nr_hw_queues;
block->tag_set.queue_depth = queue_depth;
block->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
block->tag_set.numa_node = NUMA_NO_NODE;
rc = blk_mq_alloc_tag_set(&block->tag_set);
if (rc)
return rc;
gdp = blk_mq_alloc_disk(&block->tag_set, &lim, block);
if (IS_ERR(gdp)) {
blk_mq_free_tag_set(&block->tag_set);
return PTR_ERR(gdp);
}
/* Initialize gendisk structure. */
gdp->major = DASD_MAJOR;
gdp->first_minor = base->devindex << DASD_PARTN_BITS;
gdp->minors = 1 << 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);
block->gdp = gdp;
set_capacity(block->gdp, 0);
rc = device_add_disk(&base->cdev->dev, block->gdp, NULL);
if (rc) {
dasd_gendisk_free(block);
return rc;
}
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;
blk_mq_free_tag_set(&block->tag_set);
}
}
/*
* Trigger a partition detection.
*/
int dasd_scan_partitions(struct dasd_block *block)
{
struct file *bdev_file;
int rc;
bdev_file = bdev_file_open_by_dev(disk_devt(block->gdp), BLK_OPEN_READ,
NULL, NULL);
if (IS_ERR(bdev_file)) {
DBF_DEV_EVENT(DBF_ERR, block->base,
"scan partitions error, blkdev_get returned %ld",
PTR_ERR(bdev_file));
return -ENODEV;
}
mutex_lock(&block->gdp->open_mutex);
rc = bdev_disk_changed(block->gdp, false);
mutex_unlock(&block->gdp->open_mutex);
if (rc)
DBF_DEV_EVENT(DBF_ERR, block->base,
"scan partitions error, rc %d", rc);
/*
* Since the matching fput() call to the
* bdev_file_open_by_path() 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_file
* (see dasd_generic_set_offline). As long as the partition detection
* is running no offline should be allowed. That is why the assignment
* to block->bdev_file is done AFTER the BLKRRPART ioctl.
*/
block->bdev_file = bdev_file;
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 file *bdev_file;
/*
* Get the bdev_file pointer from the device structure and clear
* device->bdev_file to lower the offline open_count limit again.
*/
bdev_file = block->bdev_file;
block->bdev_file = NULL;
mutex_lock(&file_bdev(bdev_file)->bd_disk->open_mutex);
bdev_disk_changed(file_bdev(bdev_file)->bd_disk, true);
mutex_unlock(&file_bdev(bdev_file)->bd_disk->open_mutex);
/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
fput(bdev_file);
}
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");
}
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