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 */
dasd_gendisk_alloc(struct dasd_block * block)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 = __alloc_disk_node(block->request_queue, NUMA_NO_NODE,
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 */
dasd_gendisk_free(struct dasd_block * block)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 */
dasd_scan_partitions(struct dasd_block * block)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 */
dasd_destroy_partitions(struct dasd_block * block)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
dasd_gendisk_init(void)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
dasd_gendisk_exit(void)180 void dasd_gendisk_exit(void)
181 {
182 unregister_blkdev(DASD_MAJOR, "dasd");
183 }
184