1 // SPDX-License-Identifier: GPL-2.0 2 /* 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, 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/major.h> 18 #include <linux/fs.h> 19 #include <linux/blkpg.h> 20 21 #include <linux/uaccess.h> 22 23 /* This is ugly... */ 24 #define PRINTK_HEADER "dasd_gendisk:" 25 26 #include "dasd_int.h" 27 28 static struct lock_class_key dasd_bio_compl_lkclass; 29 30 /* 31 * Allocate and register gendisk structure for device. 32 */ 33 int dasd_gendisk_alloc(struct dasd_block *block) 34 { 35 struct gendisk *gdp; 36 struct dasd_device *base; 37 int len, rc; 38 39 /* Make sure the minor for this device exists. */ 40 base = block->base; 41 if (base->devindex >= DASD_PER_MAJOR) 42 return -EBUSY; 43 44 gdp = blk_mq_alloc_disk_for_queue(block->request_queue, 45 &dasd_bio_compl_lkclass); 46 if (!gdp) 47 return -ENOMEM; 48 49 /* Initialize gendisk structure. */ 50 gdp->major = DASD_MAJOR; 51 gdp->first_minor = base->devindex << DASD_PARTN_BITS; 52 gdp->minors = 1 << DASD_PARTN_BITS; 53 gdp->fops = &dasd_device_operations; 54 55 /* 56 * Set device name. 57 * dasda - dasdz : 26 devices 58 * dasdaa - dasdzz : 676 devices, added up = 702 59 * dasdaaa - dasdzzz : 17576 devices, added up = 18278 60 * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252 61 */ 62 len = sprintf(gdp->disk_name, "dasd"); 63 if (base->devindex > 25) { 64 if (base->devindex > 701) { 65 if (base->devindex > 18277) 66 len += sprintf(gdp->disk_name + len, "%c", 67 'a'+(((base->devindex-18278) 68 /17576)%26)); 69 len += sprintf(gdp->disk_name + len, "%c", 70 'a'+(((base->devindex-702)/676)%26)); 71 } 72 len += sprintf(gdp->disk_name + len, "%c", 73 'a'+(((base->devindex-26)/26)%26)); 74 } 75 len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26)); 76 77 if (base->features & DASD_FEATURE_READONLY || 78 test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) 79 set_disk_ro(gdp, 1); 80 dasd_add_link_to_gendisk(gdp, base); 81 block->gdp = gdp; 82 set_capacity(block->gdp, 0); 83 84 rc = device_add_disk(&base->cdev->dev, block->gdp, NULL); 85 if (rc) { 86 dasd_gendisk_free(block); 87 return rc; 88 } 89 90 return 0; 91 } 92 93 /* 94 * Unregister and free gendisk structure for device. 95 */ 96 void dasd_gendisk_free(struct dasd_block *block) 97 { 98 if (block->gdp) { 99 del_gendisk(block->gdp); 100 block->gdp->private_data = NULL; 101 put_disk(block->gdp); 102 block->gdp = NULL; 103 } 104 } 105 106 /* 107 * Trigger a partition detection. 108 */ 109 int dasd_scan_partitions(struct dasd_block *block) 110 { 111 struct block_device *bdev; 112 int rc; 113 114 bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL); 115 if (IS_ERR(bdev)) { 116 DBF_DEV_EVENT(DBF_ERR, block->base, 117 "scan partitions error, blkdev_get returned %ld", 118 PTR_ERR(bdev)); 119 return -ENODEV; 120 } 121 122 mutex_lock(&block->gdp->open_mutex); 123 rc = bdev_disk_changed(block->gdp, false); 124 mutex_unlock(&block->gdp->open_mutex); 125 if (rc) 126 DBF_DEV_EVENT(DBF_ERR, block->base, 127 "scan partitions error, rc %d", rc); 128 129 /* 130 * Since the matching blkdev_put call to the blkdev_get in 131 * this function is not called before dasd_destroy_partitions 132 * the offline open_count limit needs to be increased from 133 * 0 to 1. This is done by setting device->bdev (see 134 * dasd_generic_set_offline). As long as the partition 135 * detection is running no offline should be allowed. That 136 * is why the assignment to device->bdev is done AFTER 137 * the BLKRRPART ioctl. 138 */ 139 block->bdev = bdev; 140 return 0; 141 } 142 143 /* 144 * Remove all inodes in the system for a device, delete the 145 * partitions and make device unusable by setting its size to zero. 146 */ 147 void dasd_destroy_partitions(struct dasd_block *block) 148 { 149 struct block_device *bdev; 150 151 /* 152 * Get the bdev pointer from the device structure and clear 153 * device->bdev to lower the offline open_count limit again. 154 */ 155 bdev = block->bdev; 156 block->bdev = NULL; 157 158 mutex_lock(&bdev->bd_disk->open_mutex); 159 bdev_disk_changed(bdev->bd_disk, true); 160 mutex_unlock(&bdev->bd_disk->open_mutex); 161 162 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */ 163 blkdev_put(bdev, FMODE_READ); 164 } 165 166 int dasd_gendisk_init(void) 167 { 168 int rc; 169 170 /* Register to static dasd major 94 */ 171 rc = register_blkdev(DASD_MAJOR, "dasd"); 172 if (rc != 0) { 173 pr_warn("Registering the device driver with major number %d failed\n", 174 DASD_MAJOR); 175 return rc; 176 } 177 return 0; 178 } 179 180 void dasd_gendisk_exit(void) 181 { 182 unregister_blkdev(DASD_MAJOR, "dasd"); 183 } 184