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