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 /* 28 * Allocate and register gendisk structure for device. 29 */ 30 int dasd_gendisk_alloc(struct dasd_block *block) 31 { 32 struct gendisk *gdp; 33 struct dasd_device *base; 34 int len; 35 36 /* Make sure the minor for this device exists. */ 37 base = block->base; 38 if (base->devindex >= DASD_PER_MAJOR) 39 return -EBUSY; 40 41 gdp = alloc_disk(1 << DASD_PARTN_BITS); 42 if (!gdp) 43 return -ENOMEM; 44 45 /* Initialize gendisk structure. */ 46 gdp->major = DASD_MAJOR; 47 gdp->first_minor = base->devindex << DASD_PARTN_BITS; 48 gdp->fops = &dasd_device_operations; 49 50 /* 51 * Set device name. 52 * dasda - dasdz : 26 devices 53 * dasdaa - dasdzz : 676 devices, added up = 702 54 * dasdaaa - dasdzzz : 17576 devices, added up = 18278 55 * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252 56 */ 57 len = sprintf(gdp->disk_name, "dasd"); 58 if (base->devindex > 25) { 59 if (base->devindex > 701) { 60 if (base->devindex > 18277) 61 len += sprintf(gdp->disk_name + len, "%c", 62 'a'+(((base->devindex-18278) 63 /17576)%26)); 64 len += sprintf(gdp->disk_name + len, "%c", 65 'a'+(((base->devindex-702)/676)%26)); 66 } 67 len += sprintf(gdp->disk_name + len, "%c", 68 'a'+(((base->devindex-26)/26)%26)); 69 } 70 len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26)); 71 72 if (base->features & DASD_FEATURE_READONLY || 73 test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) 74 set_disk_ro(gdp, 1); 75 dasd_add_link_to_gendisk(gdp, base); 76 gdp->queue = block->request_queue; 77 block->gdp = gdp; 78 set_capacity(block->gdp, 0); 79 device_add_disk(&base->cdev->dev, block->gdp, NULL); 80 return 0; 81 } 82 83 /* 84 * Unregister and free gendisk structure for device. 85 */ 86 void dasd_gendisk_free(struct dasd_block *block) 87 { 88 if (block->gdp) { 89 del_gendisk(block->gdp); 90 block->gdp->private_data = NULL; 91 put_disk(block->gdp); 92 block->gdp = NULL; 93 } 94 } 95 96 /* 97 * Trigger a partition detection. 98 */ 99 int dasd_scan_partitions(struct dasd_block *block) 100 { 101 struct block_device *bdev; 102 int rc; 103 104 bdev = bdget_disk(block->gdp, 0); 105 if (!bdev) { 106 DBF_DEV_EVENT(DBF_ERR, block->base, "%s", 107 "scan partitions error, bdget returned NULL"); 108 return -ENODEV; 109 } 110 111 rc = blkdev_get(bdev, FMODE_READ, NULL); 112 if (rc < 0) { 113 DBF_DEV_EVENT(DBF_ERR, block->base, 114 "scan partitions error, blkdev_get returned %d", 115 rc); 116 return -ENODEV; 117 } 118 119 mutex_lock(&bdev->bd_mutex); 120 rc = bdev_disk_changed(bdev, false); 121 mutex_unlock(&bdev->bd_mutex); 122 if (rc) 123 DBF_DEV_EVENT(DBF_ERR, block->base, 124 "scan partitions error, rc %d", rc); 125 126 /* 127 * Since the matching blkdev_put call to the blkdev_get in 128 * this function is not called before dasd_destroy_partitions 129 * the offline open_count limit needs to be increased from 130 * 0 to 1. This is done by setting device->bdev (see 131 * dasd_generic_set_offline). As long as the partition 132 * detection is running no offline should be allowed. That 133 * is why the assignment to device->bdev is done AFTER 134 * the BLKRRPART ioctl. 135 */ 136 block->bdev = bdev; 137 return 0; 138 } 139 140 /* 141 * Remove all inodes in the system for a device, delete the 142 * partitions and make device unusable by setting its size to zero. 143 */ 144 void dasd_destroy_partitions(struct dasd_block *block) 145 { 146 /* The two structs have 168/176 byte on 31/64 bit. */ 147 struct blkpg_partition bpart; 148 struct blkpg_ioctl_arg barg; 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 /* 159 * See fs/partition/check.c:delete_partition 160 * Can't call delete_partitions directly. Use ioctl. 161 * The ioctl also does locking and invalidation. 162 */ 163 memset(&bpart, 0, sizeof(struct blkpg_partition)); 164 memset(&barg, 0, sizeof(struct blkpg_ioctl_arg)); 165 barg.data = (void __force __user *) &bpart; 166 barg.op = BLKPG_DEL_PARTITION; 167 for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--) 168 ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg); 169 170 invalidate_partition(block->gdp, 0); 171 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */ 172 blkdev_put(bdev, FMODE_READ); 173 set_capacity(block->gdp, 0); 174 } 175 176 int dasd_gendisk_init(void) 177 { 178 int rc; 179 180 /* Register to static dasd major 94 */ 181 rc = register_blkdev(DASD_MAJOR, "dasd"); 182 if (rc != 0) { 183 pr_warn("Registering the device driver with major number %d failed\n", 184 DASD_MAJOR); 185 return rc; 186 } 187 return 0; 188 } 189 190 void dasd_gendisk_exit(void) 191 { 192 unregister_blkdev(DASD_MAJOR, "dasd"); 193 } 194