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
28static unsigned int queue_depth = 32;
29static unsigned int nr_hw_queues = 4;
30
31module_param(queue_depth, uint, 0444);
32MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
33
34module_param(nr_hw_queues, uint, 0444);
35MODULE_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 */
40int 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 */
114void 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 */
128int 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 */
167void 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
186int 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
200void dasd_gendisk_exit(void)
201{
202	unregister_blkdev(DASD_MAJOR, "dasd");
203}
204