xref: /openbmc/linux/drivers/s390/block/dasd_genhd.c (revision 4800cd83)
1 /*
2  * File...........: linux/drivers/s390/block/dasd_genhd.c
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  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 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 <asm/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  */
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 	gdp->driverfs_dev = &base->cdev->dev;
50 
51 	/*
52 	 * Set device name.
53 	 *   dasda - dasdz : 26 devices
54 	 *   dasdaa - dasdzz : 676 devices, added up = 702
55 	 *   dasdaaa - dasdzzz : 17576 devices, added up = 18278
56 	 *   dasdaaaa - dasdzzzz : 456976 devices, added up = 475252
57 	 */
58 	len = sprintf(gdp->disk_name, "dasd");
59 	if (base->devindex > 25) {
60 		if (base->devindex > 701) {
61 			if (base->devindex > 18277)
62 			        len += sprintf(gdp->disk_name + len, "%c",
63 					       'a'+(((base->devindex-18278)
64 						     /17576)%26));
65 			len += sprintf(gdp->disk_name + len, "%c",
66 				       'a'+(((base->devindex-702)/676)%26));
67 		}
68 		len += sprintf(gdp->disk_name + len, "%c",
69 			       'a'+(((base->devindex-26)/26)%26));
70 	}
71 	len += sprintf(gdp->disk_name + len, "%c", 'a'+(base->devindex%26));
72 
73 	if (base->features & DASD_FEATURE_READONLY ||
74 	    test_bit(DASD_FLAG_DEVICE_RO, &base->flags))
75 		set_disk_ro(gdp, 1);
76 	gdp->private_data = block;
77 	gdp->queue = block->request_queue;
78 	block->gdp = gdp;
79 	set_capacity(block->gdp, 0);
80 	add_disk(block->gdp);
81 	return 0;
82 }
83 
84 /*
85  * Unregister and free gendisk structure for device.
86  */
87 void dasd_gendisk_free(struct dasd_block *block)
88 {
89 	if (block->gdp) {
90 		del_gendisk(block->gdp);
91 		block->gdp->queue = NULL;
92 		block->gdp->private_data = NULL;
93 		put_disk(block->gdp);
94 		block->gdp = NULL;
95 	}
96 }
97 
98 /*
99  * Trigger a partition detection.
100  */
101 int dasd_scan_partitions(struct dasd_block *block)
102 {
103 	struct block_device *bdev;
104 
105 	bdev = bdget_disk(block->gdp, 0);
106 	if (!bdev || blkdev_get(bdev, FMODE_READ, NULL) < 0)
107 		return -ENODEV;
108 	/*
109 	 * See fs/partition/check.c:register_disk,rescan_partitions
110 	 * Can't call rescan_partitions directly. Use ioctl.
111 	 */
112 	ioctl_by_bdev(bdev, BLKRRPART, 0);
113 	/*
114 	 * Since the matching blkdev_put call to the blkdev_get in
115 	 * this function is not called before dasd_destroy_partitions
116 	 * the offline open_count limit needs to be increased from
117 	 * 0 to 1. This is done by setting device->bdev (see
118 	 * dasd_generic_set_offline). As long as the partition
119 	 * detection is running no offline should be allowed. That
120 	 * is why the assignment to device->bdev is done AFTER
121 	 * the BLKRRPART ioctl.
122 	 */
123 	block->bdev = bdev;
124 	return 0;
125 }
126 
127 /*
128  * Remove all inodes in the system for a device, delete the
129  * partitions and make device unusable by setting its size to zero.
130  */
131 void dasd_destroy_partitions(struct dasd_block *block)
132 {
133 	/* The two structs have 168/176 byte on 31/64 bit. */
134 	struct blkpg_partition bpart;
135 	struct blkpg_ioctl_arg barg;
136 	struct block_device *bdev;
137 
138 	/*
139 	 * Get the bdev pointer from the device structure and clear
140 	 * device->bdev to lower the offline open_count limit again.
141 	 */
142 	bdev = block->bdev;
143 	block->bdev = NULL;
144 
145 	/*
146 	 * See fs/partition/check.c:delete_partition
147 	 * Can't call delete_partitions directly. Use ioctl.
148 	 * The ioctl also does locking and invalidation.
149 	 */
150 	memset(&bpart, 0, sizeof(struct blkpg_partition));
151 	memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
152 	barg.data = (void __force __user *) &bpart;
153 	barg.op = BLKPG_DEL_PARTITION;
154 	for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
155 		ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
156 
157 	invalidate_partition(block->gdp, 0);
158 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
159 	blkdev_put(bdev, FMODE_READ);
160 	set_capacity(block->gdp, 0);
161 }
162 
163 int dasd_gendisk_init(void)
164 {
165 	int rc;
166 
167 	/* Register to static dasd major 94 */
168 	rc = register_blkdev(DASD_MAJOR, "dasd");
169 	if (rc != 0) {
170 		pr_warning("Registering the device driver with major number "
171 			   "%d failed\n", DASD_MAJOR);
172 		return rc;
173 	}
174 	return 0;
175 }
176 
177 void dasd_gendisk_exit(void)
178 {
179 	unregister_blkdev(DASD_MAJOR, "dasd");
180 }
181