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 unsigned int queue_depth = 32; 29 static unsigned int nr_hw_queues = 4; 30 31 module_param(queue_depth, uint, 0444); 32 MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices"); 33 34 module_param(nr_hw_queues, uint, 0444); 35 MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices"); 36 37 /* 38 * Allocate and register gendisk structure for device. 39 */ 40 int dasd_gendisk_alloc(struct dasd_block *block) 41 { 42 struct gendisk *gdp; 43 struct dasd_device *base; 44 int len, rc; 45 46 /* Make sure the minor for this device exists. */ 47 base = block->base; 48 if (base->devindex >= DASD_PER_MAJOR) 49 return -EBUSY; 50 51 block->tag_set.ops = &dasd_mq_ops; 52 block->tag_set.cmd_size = sizeof(struct dasd_ccw_req); 53 block->tag_set.nr_hw_queues = nr_hw_queues; 54 block->tag_set.queue_depth = queue_depth; 55 block->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 56 block->tag_set.numa_node = NUMA_NO_NODE; 57 rc = blk_mq_alloc_tag_set(&block->tag_set); 58 if (rc) 59 return rc; 60 61 gdp = blk_mq_alloc_disk(&block->tag_set, block); 62 if (IS_ERR(gdp)) { 63 blk_mq_free_tag_set(&block->tag_set); 64 return PTR_ERR(gdp); 65 } 66 67 /* Initialize gendisk structure. */ 68 gdp->major = DASD_MAJOR; 69 gdp->first_minor = base->devindex << DASD_PARTN_BITS; 70 gdp->minors = 1 << DASD_PARTN_BITS; 71 gdp->fops = &dasd_device_operations; 72 73 /* 74 * Set device name. 75 * dasda - dasdz : 26 devices 76 * dasdaa - dasdzz : 676 devices, added up = 702 77 * dasdaaa - dasdzzz : 17576 devices, added up = 18278 78 * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252 79 */ 80 len = sprintf(gdp->disk_name, "dasd"); 81 if (base->devindex > 25) { 82 if (base->devindex > 701) { 83 if (base->devindex > 18277) 84 len += sprintf(gdp->disk_name + len, "%c", 85 'a'+(((base->devindex-18278) 86 /17576)%26)); 87 len += sprintf(gdp->disk_name + len, "%c", 88 'a'+(((base->devindex-702)/676)%26)); 89 } 90 len += sprintf(gdp->disk_name + len, "%c", 91 'a'+(((base->devindex-26)/26)%26)); 92 } 93 len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26)); 94 95 if (base->features & DASD_FEATURE_READONLY || 96 test_bit(DASD_FLAG_DEVICE_RO, &base->flags)) 97 set_disk_ro(gdp, 1); 98 dasd_add_link_to_gendisk(gdp, base); 99 block->gdp = gdp; 100 set_capacity(block->gdp, 0); 101 102 rc = device_add_disk(&base->cdev->dev, block->gdp, NULL); 103 if (rc) { 104 dasd_gendisk_free(block); 105 return rc; 106 } 107 108 return 0; 109 } 110 111 /* 112 * Unregister and free gendisk structure for device. 113 */ 114 void dasd_gendisk_free(struct dasd_block *block) 115 { 116 if (block->gdp) { 117 del_gendisk(block->gdp); 118 block->gdp->private_data = NULL; 119 put_disk(block->gdp); 120 block->gdp = NULL; 121 blk_mq_free_tag_set(&block->tag_set); 122 } 123 } 124 125 /* 126 * Trigger a partition detection. 127 */ 128 int dasd_scan_partitions(struct dasd_block *block) 129 { 130 struct block_device *bdev; 131 int rc; 132 133 bdev = blkdev_get_by_dev(disk_devt(block->gdp), BLK_OPEN_READ, NULL, 134 NULL); 135 if (IS_ERR(bdev)) { 136 DBF_DEV_EVENT(DBF_ERR, block->base, 137 "scan partitions error, blkdev_get returned %ld", 138 PTR_ERR(bdev)); 139 return -ENODEV; 140 } 141 142 mutex_lock(&block->gdp->open_mutex); 143 rc = bdev_disk_changed(block->gdp, false); 144 mutex_unlock(&block->gdp->open_mutex); 145 if (rc) 146 DBF_DEV_EVENT(DBF_ERR, block->base, 147 "scan partitions error, rc %d", rc); 148 149 /* 150 * Since the matching blkdev_put call to the blkdev_get in 151 * this function is not called before dasd_destroy_partitions 152 * the offline open_count limit needs to be increased from 153 * 0 to 1. This is done by setting device->bdev (see 154 * dasd_generic_set_offline). As long as the partition 155 * detection is running no offline should be allowed. That 156 * is why the assignment to device->bdev is done AFTER 157 * the BLKRRPART ioctl. 158 */ 159 block->bdev = bdev; 160 return 0; 161 } 162 163 /* 164 * Remove all inodes in the system for a device, delete the 165 * partitions and make device unusable by setting its size to zero. 166 */ 167 void dasd_destroy_partitions(struct dasd_block *block) 168 { 169 struct block_device *bdev; 170 171 /* 172 * Get the bdev pointer from the device structure and clear 173 * device->bdev to lower the offline open_count limit again. 174 */ 175 bdev = block->bdev; 176 block->bdev = NULL; 177 178 mutex_lock(&bdev->bd_disk->open_mutex); 179 bdev_disk_changed(bdev->bd_disk, true); 180 mutex_unlock(&bdev->bd_disk->open_mutex); 181 182 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */ 183 blkdev_put(bdev, NULL); 184 } 185 186 int dasd_gendisk_init(void) 187 { 188 int rc; 189 190 /* Register to static dasd major 94 */ 191 rc = register_blkdev(DASD_MAJOR, "dasd"); 192 if (rc != 0) { 193 pr_warn("Registering the device driver with major number %d failed\n", 194 DASD_MAJOR); 195 return rc; 196 } 197 return 0; 198 } 199 200 void dasd_gendisk_exit(void) 201 { 202 unregister_blkdev(DASD_MAJOR, "dasd"); 203 } 204