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 #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 static void dasd_gd_free(struct gendisk *gdp);
26
27 module_param(queue_depth, uint, 0444);
28 MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
29
30 module_param(nr_hw_queues, uint, 0444);
31 MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");
32
33 /*
34 * Set device name.
35 * dasda - dasdz : 26 devices
36 * dasdaa - dasdzz : 676 devices, added up = 702
37 * dasdaaa - dasdzzz : 17576 devices, added up = 18278
38 * dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
39 */
dasd_name_format(char * prefix,int index,char * buf,int buflen)40 static int dasd_name_format(char *prefix, int index, char *buf, int buflen)
41 {
42 const int base = 'z' - 'a' + 1;
43 char *begin = buf + strlen(prefix);
44 char *end = buf + buflen;
45 char *p;
46 int unit;
47
48 p = end - 1;
49 *p = '\0';
50 unit = base;
51 do {
52 if (p == begin)
53 return -EINVAL;
54 *--p = 'a' + (index % unit);
55 index = (index / unit) - 1;
56 } while (index >= 0);
57
58 memmove(begin, p, end - p);
59 memcpy(buf, prefix, strlen(prefix));
60
61 return 0;
62 }
63
64 /*
65 * Allocate and register gendisk structure for device.
66 */
dasd_gendisk_alloc(struct dasd_block * block)67 int dasd_gendisk_alloc(struct dasd_block *block)
68 {
69 struct queue_limits lim = {
70 /*
71 * With page sized segments, each segment can be translated into
72 * one idaw/tidaw.
73 */
74 .max_segment_size = PAGE_SIZE,
75 .seg_boundary_mask = PAGE_SIZE - 1,
76 .max_segments = USHRT_MAX,
77 };
78 struct gendisk *gdp;
79 struct dasd_device *base;
80 unsigned int devindex;
81 int rc;
82
83 /* Make sure the minor for this device exists. */
84 base = block->base;
85 devindex = base->devindex;
86 if (devindex >= DASD_PER_MAJOR)
87 return -EBUSY;
88
89 block->tag_set.ops = &dasd_mq_ops;
90 block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);
91 block->tag_set.nr_hw_queues = nr_hw_queues;
92 block->tag_set.queue_depth = queue_depth;
93 block->tag_set.numa_node = NUMA_NO_NODE;
94 rc = blk_mq_alloc_tag_set(&block->tag_set);
95 if (rc)
96 return rc;
97
98 gdp = blk_mq_alloc_disk(&block->tag_set, &lim, block);
99 if (IS_ERR(gdp)) {
100 blk_mq_free_tag_set(&block->tag_set);
101 return PTR_ERR(gdp);
102 }
103
104 /* Initialize gendisk structure. */
105 gdp->major = DASD_MAJOR;
106 gdp->first_minor = devindex << DASD_PARTN_BITS;
107 gdp->minors = 1 << DASD_PARTN_BITS;
108 gdp->fops = &dasd_device_operations;
109
110 rc = dasd_name_format("dasd", devindex, gdp->disk_name, sizeof(gdp->disk_name));
111 if (rc) {
112 DBF_DEV_EVENT(DBF_ERR, block->base,
113 "setting disk name failed, rc %d", rc);
114 dasd_gd_free(gdp);
115 return rc;
116 }
117
118 if (base->features & DASD_FEATURE_READONLY ||
119 test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
120 set_disk_ro(gdp, 1);
121 dasd_add_link_to_gendisk(gdp, base);
122 block->gdp = gdp;
123 set_capacity(block->gdp, 0);
124
125 rc = device_add_disk(&base->cdev->dev, block->gdp, NULL);
126 if (rc) {
127 dasd_gendisk_free(block);
128 return rc;
129 }
130
131 return 0;
132 }
133
134 /*
135 * Free gendisk structure
136 */
dasd_gd_free(struct gendisk * gd)137 static void dasd_gd_free(struct gendisk *gd)
138 {
139 del_gendisk(gd);
140 gd->private_data = NULL;
141 put_disk(gd);
142 }
143
144 /*
145 * Unregister and free gendisk structure for device.
146 */
dasd_gendisk_free(struct dasd_block * block)147 void dasd_gendisk_free(struct dasd_block *block)
148 {
149 if (block->gdp) {
150 dasd_gd_free(block->gdp);
151 block->gdp = NULL;
152 blk_mq_free_tag_set(&block->tag_set);
153 }
154 }
155
156 /*
157 * Trigger a partition detection.
158 */
dasd_scan_partitions(struct dasd_block * block)159 int dasd_scan_partitions(struct dasd_block *block)
160 {
161 struct file *bdev_file;
162 int rc;
163
164 bdev_file = bdev_file_open_by_dev(disk_devt(block->gdp), BLK_OPEN_READ,
165 NULL, NULL);
166 if (IS_ERR(bdev_file)) {
167 DBF_DEV_EVENT(DBF_ERR, block->base,
168 "scan partitions error, blkdev_get returned %ld",
169 PTR_ERR(bdev_file));
170 return -ENODEV;
171 }
172
173 mutex_lock(&block->gdp->open_mutex);
174 rc = bdev_disk_changed(block->gdp, false);
175 mutex_unlock(&block->gdp->open_mutex);
176 if (rc)
177 DBF_DEV_EVENT(DBF_ERR, block->base,
178 "scan partitions error, rc %d", rc);
179
180 /*
181 * Since the matching fput() call to the
182 * bdev_file_open_by_path() in this function is not called before
183 * dasd_destroy_partitions the offline open_count limit needs to be
184 * increased from 0 to 1. This is done by setting device->bdev_file
185 * (see dasd_generic_set_offline). As long as the partition detection
186 * is running no offline should be allowed. That is why the assignment
187 * to block->bdev_file is done AFTER the BLKRRPART ioctl.
188 */
189 block->bdev_file = bdev_file;
190 return 0;
191 }
192
193 /*
194 * Remove all inodes in the system for a device, delete the
195 * partitions and make device unusable by setting its size to zero.
196 */
dasd_destroy_partitions(struct dasd_block * block)197 void dasd_destroy_partitions(struct dasd_block *block)
198 {
199 struct file *bdev_file;
200
201 /*
202 * Get the bdev_file pointer from the device structure and clear
203 * device->bdev_file to lower the offline open_count limit again.
204 */
205 bdev_file = block->bdev_file;
206 block->bdev_file = NULL;
207
208 mutex_lock(&file_bdev(bdev_file)->bd_disk->open_mutex);
209 bdev_disk_changed(file_bdev(bdev_file)->bd_disk, true);
210 mutex_unlock(&file_bdev(bdev_file)->bd_disk->open_mutex);
211
212 /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
213 fput(bdev_file);
214 }
215
dasd_gendisk_init(void)216 int dasd_gendisk_init(void)
217 {
218 int rc;
219
220 /* Register to static dasd major 94 */
221 rc = register_blkdev(DASD_MAJOR, "dasd");
222 if (rc != 0) {
223 pr_warn("Registering the device driver with major number %d failed\n",
224 DASD_MAJOR);
225 return rc;
226 }
227 return 0;
228 }
229
dasd_gendisk_exit(void)230 void dasd_gendisk_exit(void)
231 {
232 unregister_blkdev(DASD_MAJOR, "dasd");
233 }
234