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 */
dasd_gendisk_alloc(struct dasd_block * block)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 */
dasd_gendisk_free(struct dasd_block * block)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 */
dasd_scan_partitions(struct dasd_block * block)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 */
dasd_destroy_partitions(struct dasd_block * block)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
dasd_gendisk_init(void)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
dasd_gendisk_exit(void)173 void dasd_gendisk_exit(void)
174 {
175 unregister_blkdev(DASD_MAJOR, "dasd");
176 }
177
