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1// SPDX-License-Identifier: GPL-2.02/*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 * Copyright IBM Corp. 1999, 20019 *10 * gendisk related functions for the dasd driver.11 *12 */13 14#include <linux/interrupt.h>15#include <linux/major.h>16#include <linux/fs.h>17#include <linux/blkpg.h>18 19#include <linux/uaccess.h>20 21#include "dasd_int.h"22 23static unsigned int queue_depth = 32;24static unsigned int nr_hw_queues = 4;25 26module_param(queue_depth, uint, 0444);27MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");28 29module_param(nr_hw_queues, uint, 0444);30MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");31 32/*33 * Allocate and register gendisk structure for device.34 */35int dasd_gendisk_alloc(struct dasd_block *block)36{37 struct queue_limits lim = {38 /*39 * With page sized segments, each segment can be translated into40 * one idaw/tidaw.41 */42 .max_segment_size = PAGE_SIZE,43 .seg_boundary_mask = PAGE_SIZE - 1,44 .max_segments = USHRT_MAX,45 };46 struct gendisk *gdp;47 struct dasd_device *base;48 int len, rc;49 50 /* Make sure the minor for this device exists. */51 base = block->base;52 if (base->devindex >= DASD_PER_MAJOR)53 return -EBUSY;54 55 block->tag_set.ops = &dasd_mq_ops;56 block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);57 block->tag_set.nr_hw_queues = nr_hw_queues;58 block->tag_set.queue_depth = queue_depth;59 block->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;60 block->tag_set.numa_node = NUMA_NO_NODE;61 rc = blk_mq_alloc_tag_set(&block->tag_set);62 if (rc)63 return rc;64 65 gdp = blk_mq_alloc_disk(&block->tag_set, &lim, block);66 if (IS_ERR(gdp)) {67 blk_mq_free_tag_set(&block->tag_set);68 return PTR_ERR(gdp);69 }70 71 /* Initialize gendisk structure. */72 gdp->major = DASD_MAJOR;73 gdp->first_minor = base->devindex << DASD_PARTN_BITS;74 gdp->minors = 1 << DASD_PARTN_BITS;75 gdp->fops = &dasd_device_operations;76 77 /*78 * Set device name.79 * dasda - dasdz : 26 devices80 * dasdaa - dasdzz : 676 devices, added up = 70281 * dasdaaa - dasdzzz : 17576 devices, added up = 1827882 * dasdaaaa - dasdzzzz : 456976 devices, added up = 47525283 */84 len = sprintf(gdp->disk_name, "dasd");85 if (base->devindex > 25) {86 if (base->devindex > 701) {87 if (base->devindex > 18277)88 len += sprintf(gdp->disk_name + len, "%c",89 'a'+(((base->devindex-18278)90 /17576)%26));91 len += sprintf(gdp->disk_name + len, "%c",92 'a'+(((base->devindex-702)/676)%26));93 }94 len += sprintf(gdp->disk_name + len, "%c",95 'a'+(((base->devindex-26)/26)%26));96 }97 len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));98 99 if (base->features & DASD_FEATURE_READONLY ||100 test_bit(DASD_FLAG_DEVICE_RO, &base->flags))101 set_disk_ro(gdp, 1);102 dasd_add_link_to_gendisk(gdp, base);103 block->gdp = gdp;104 set_capacity(block->gdp, 0);105 106 rc = device_add_disk(&base->cdev->dev, block->gdp, NULL);107 if (rc) {108 dasd_gendisk_free(block);109 return rc;110 }111 112 return 0;113}114 115/*116 * Unregister and free gendisk structure for device.117 */118void dasd_gendisk_free(struct dasd_block *block)119{120 if (block->gdp) {121 del_gendisk(block->gdp);122 block->gdp->private_data = NULL;123 put_disk(block->gdp);124 block->gdp = NULL;125 blk_mq_free_tag_set(&block->tag_set);126 }127}128 129/*130 * Trigger a partition detection.131 */132int dasd_scan_partitions(struct dasd_block *block)133{134 struct file *bdev_file;135 int rc;136 137 bdev_file = bdev_file_open_by_dev(disk_devt(block->gdp), BLK_OPEN_READ,138 NULL, NULL);139 if (IS_ERR(bdev_file)) {140 DBF_DEV_EVENT(DBF_ERR, block->base,141 "scan partitions error, blkdev_get returned %ld",142 PTR_ERR(bdev_file));143 return -ENODEV;144 }145 146 mutex_lock(&block->gdp->open_mutex);147 rc = bdev_disk_changed(block->gdp, false);148 mutex_unlock(&block->gdp->open_mutex);149 if (rc)150 DBF_DEV_EVENT(DBF_ERR, block->base,151 "scan partitions error, rc %d", rc);152 153 /*154 * Since the matching fput() call to the155 * bdev_file_open_by_path() in this function is not called before156 * dasd_destroy_partitions the offline open_count limit needs to be157 * increased from 0 to 1. This is done by setting device->bdev_file158 * (see dasd_generic_set_offline). As long as the partition detection159 * is running no offline should be allowed. That is why the assignment160 * to block->bdev_file is done AFTER the BLKRRPART ioctl.161 */162 block->bdev_file = bdev_file;163 return 0;164}165 166/*167 * Remove all inodes in the system for a device, delete the168 * partitions and make device unusable by setting its size to zero.169 */170void dasd_destroy_partitions(struct dasd_block *block)171{172 struct file *bdev_file;173 174 /*175 * Get the bdev_file pointer from the device structure and clear176 * device->bdev_file to lower the offline open_count limit again.177 */178 bdev_file = block->bdev_file;179 block->bdev_file = NULL;180 181 mutex_lock(&file_bdev(bdev_file)->bd_disk->open_mutex);182 bdev_disk_changed(file_bdev(bdev_file)->bd_disk, true);183 mutex_unlock(&file_bdev(bdev_file)->bd_disk->open_mutex);184 185 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */186 fput(bdev_file);187}188 189int dasd_gendisk_init(void)190{191 int rc;192 193 /* Register to static dasd major 94 */194 rc = register_blkdev(DASD_MAJOR, "dasd");195 if (rc != 0) {196 pr_warn("Registering the device driver with major number %d failed\n",197 DASD_MAJOR);198 return rc;199 }200 return 0;201}202 203void dasd_gendisk_exit(void)204{205 unregister_blkdev(DASD_MAJOR, "dasd");206}207