1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Author(s)......: Holger Smolinski <[email protected]>
4 * Horst Hummel <[email protected]>
5 * Carsten Otte <[email protected]>
6 * Martin Schwidefsky <[email protected]>
7 * Bugreports.to..: <[email protected]>
8 * Copyright IBM Corp. 1999, 2001
9 *
10 * gendisk related functions for the dasd driver.
11 *
12 */
13
14 #include <linux/interrupt.h>
15 #include <linux/major.h>
16 #include <linux/fs.h>
17 #include <linux/blkpg.h>
18
19 #include <linux/uaccess.h>
20
21 #include "dasd_int.h"
22
23 static unsigned int queue_depth = 32;
24 static unsigned int nr_hw_queues = 4;
25
26 module_param(queue_depth, uint, 0444);
27 MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
28
29 module_param(nr_hw_queues, uint, 0444);
30 MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");
31
32 /*
33 * Allocate and register gendisk structure for device.
34 */
dasd_gendisk_alloc(struct dasd_block * block)35 int dasd_gendisk_alloc(struct dasd_block *block)
36 {
37 struct queue_limits lim = {
38 /*
39 * With page sized segments, each segment can be translated into
40 * one idaw/tidaw.
41 */
42 .max_segment_size = PAGE_SIZE,
43 .seg_boundary_mask = PAGE_SIZE - 1,
44 .max_segments = USHRT_MAX,
45 };
46 struct gendisk *gdp;
47 struct dasd_device *base;
48 int len, rc;
49
50 /* Make sure the minor for this device exists. */
51 base = block->base;
52 if (base->devindex >= DASD_PER_MAJOR)
53 return -EBUSY;
54
55 block->tag_set.ops = &dasd_mq_ops;
56 block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);
57 block->tag_set.nr_hw_queues = nr_hw_queues;
58 block->tag_set.queue_depth = queue_depth;
59 block->tag_set.numa_node = NUMA_NO_NODE;
60 rc = blk_mq_alloc_tag_set(&block->tag_set);
61 if (rc)
62 return rc;
63
64 gdp = blk_mq_alloc_disk(&block->tag_set, &lim, block);
65 if (IS_ERR(gdp)) {
66 blk_mq_free_tag_set(&block->tag_set);
67 return PTR_ERR(gdp);
68 }
69
70 /* Initialize gendisk structure. */
71 gdp->major = DASD_MAJOR;
72 gdp->first_minor = base->devindex << DASD_PARTN_BITS;
73 gdp->minors = 1 << DASD_PARTN_BITS;
74 gdp->fops = &dasd_device_operations;
75
76 /*
77 * Set device name.
78 * dasda - dasdz : 26 devices
79 * dasdaa - dasdzz : 676 devices, added up = 702
80 * dasdaaa - dasdzzz : 17576 devices, added up = 18278
81 * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
82 */
83 len = sprintf(gdp->disk_name, "dasd");
84 if (base->devindex > 25) {
85 if (base->devindex > 701) {
86 if (base->devindex > 18277)
87 len += sprintf(gdp->disk_name + len, "%c",
88 'a'+(((base->devindex-18278)
89 /17576)%26));
90 len += sprintf(gdp->disk_name + len, "%c",
91 'a'+(((base->devindex-702)/676)%26));
92 }
93 len += sprintf(gdp->disk_name + len, "%c",
94 'a'+(((base->devindex-26)/26)%26));
95 }
96 len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));
97
98 if (base->features & DASD_FEATURE_READONLY ||
99 test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
100 set_disk_ro(gdp, 1);
101 dasd_add_link_to_gendisk(gdp, base);
102 block->gdp = gdp;
103 set_capacity(block->gdp, 0);
104
105 rc = device_add_disk(&base->cdev->dev, block->gdp, NULL);
106 if (rc) {
107 dasd_gendisk_free(block);
108 return rc;
109 }
110
111 return 0;
112 }
113
114 /*
115 * Unregister and free gendisk structure for device.
116 */
dasd_gendisk_free(struct dasd_block * block)117 void dasd_gendisk_free(struct dasd_block *block)
118 {
119 if (block->gdp) {
120 del_gendisk(block->gdp);
121 block->gdp->private_data = NULL;
122 put_disk(block->gdp);
123 block->gdp = NULL;
124 blk_mq_free_tag_set(&block->tag_set);
125 }
126 }
127
128 /*
129 * Trigger a partition detection.
130 */
dasd_scan_partitions(struct dasd_block * block)131 int dasd_scan_partitions(struct dasd_block *block)
132 {
133 struct file *bdev_file;
134 int rc;
135
136 bdev_file = bdev_file_open_by_dev(disk_devt(block->gdp), BLK_OPEN_READ,
137 NULL, NULL);
138 if (IS_ERR(bdev_file)) {
139 DBF_DEV_EVENT(DBF_ERR, block->base,
140 "scan partitions error, blkdev_get returned %ld",
141 PTR_ERR(bdev_file));
142 return -ENODEV;
143 }
144
145 mutex_lock(&block->gdp->open_mutex);
146 rc = bdev_disk_changed(block->gdp, false);
147 mutex_unlock(&block->gdp->open_mutex);
148 if (rc)
149 DBF_DEV_EVENT(DBF_ERR, block->base,
150 "scan partitions error, rc %d", rc);
151
152 /*
153 * Since the matching fput() call to the
154 * bdev_file_open_by_path() in this function is not called before
155 * dasd_destroy_partitions the offline open_count limit needs to be
156 * increased from 0 to 1. This is done by setting device->bdev_file
157 * (see dasd_generic_set_offline). As long as the partition detection
158 * is running no offline should be allowed. That is why the assignment
159 * to block->bdev_file is done AFTER the BLKRRPART ioctl.
160 */
161 block->bdev_file = bdev_file;
162 return 0;
163 }
164
165 /*
166 * Remove all inodes in the system for a device, delete the
167 * partitions and make device unusable by setting its size to zero.
168 */
dasd_destroy_partitions(struct dasd_block * block)169 void dasd_destroy_partitions(struct dasd_block *block)
170 {
171 struct file *bdev_file;
172
173 /*
174 * Get the bdev_file pointer from the device structure and clear
175 * device->bdev_file to lower the offline open_count limit again.
176 */
177 bdev_file = block->bdev_file;
178 block->bdev_file = NULL;
179
180 mutex_lock(&file_bdev(bdev_file)->bd_disk->open_mutex);
181 bdev_disk_changed(file_bdev(bdev_file)->bd_disk, true);
182 mutex_unlock(&file_bdev(bdev_file)->bd_disk->open_mutex);
183
184 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
185 fput(bdev_file);
186 }
187
dasd_gendisk_init(void)188 int dasd_gendisk_init(void)
189 {
190 int rc;
191
192 /* Register to static dasd major 94 */
193 rc = register_blkdev(DASD_MAJOR, "dasd");
194 if (rc != 0) {
195 pr_warn("Registering the device driver with major number %d failed\n",
196 DASD_MAJOR);
197 return rc;
198 }
199 return 0;
200 }
201
dasd_gendisk_exit(void)202 void dasd_gendisk_exit(void)
203 {
204 unregister_blkdev(DASD_MAJOR, "dasd");
205 }
206