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 */
dasd_gendisk_alloc(struct dasd_block * block)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 */
dasd_gendisk_free(struct dasd_block * block)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 */
dasd_scan_partitions(struct dasd_block * block)99 int dasd_scan_partitions(struct dasd_block *block)
100 {
101 struct block_device *bdev;
102 int rc;
103
104 bdev = blkdev_get_by_dev(disk_devt(block->gdp), FMODE_READ, NULL);
105 if (IS_ERR(bdev)) {
106 DBF_DEV_EVENT(DBF_ERR, block->base,
107 "scan partitions error, blkdev_get returned %ld",
108 PTR_ERR(bdev));
109 return -ENODEV;
110 }
111
112 mutex_lock(&bdev->bd_mutex);
113 rc = bdev_disk_changed(bdev, false);
114 mutex_unlock(&bdev->bd_mutex);
115 if (rc)
116 DBF_DEV_EVENT(DBF_ERR, block->base,
117 "scan partitions error, rc %d", rc);
118
119 /*
120 * Since the matching blkdev_put call to the blkdev_get in
121 * this function is not called before dasd_destroy_partitions
122 * the offline open_count limit needs to be increased from
123 * 0 to 1. This is done by setting device->bdev (see
124 * dasd_generic_set_offline). As long as the partition
125 * detection is running no offline should be allowed. That
126 * is why the assignment to device->bdev is done AFTER
127 * the BLKRRPART ioctl.
128 */
129 block->bdev = bdev;
130 return 0;
131 }
132
133 /*
134 * Remove all inodes in the system for a device, delete the
135 * partitions and make device unusable by setting its size to zero.
136 */
dasd_destroy_partitions(struct dasd_block * block)137 void dasd_destroy_partitions(struct dasd_block *block)
138 {
139 struct block_device *bdev;
140
141 /*
142 * Get the bdev pointer from the device structure and clear
143 * device->bdev to lower the offline open_count limit again.
144 */
145 bdev = block->bdev;
146 block->bdev = NULL;
147
148 mutex_lock(&bdev->bd_mutex);
149 blk_drop_partitions(bdev);
150 mutex_unlock(&bdev->bd_mutex);
151
152 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
153 blkdev_put(bdev, FMODE_READ);
154 set_capacity(block->gdp, 0);
155 }
156
dasd_gendisk_init(void)157 int dasd_gendisk_init(void)
158 {
159 int rc;
160
161 /* Register to static dasd major 94 */
162 rc = register_blkdev(DASD_MAJOR, "dasd");
163 if (rc != 0) {
164 pr_warn("Registering the device driver with major number %d failed\n",
165 DASD_MAJOR);
166 return rc;
167 }
168 return 0;
169 }
170
dasd_gendisk_exit(void)171 void dasd_gendisk_exit(void)
172 {
173 unregister_blkdev(DASD_MAJOR, "dasd");
174 }
175