1/*
2 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
3 *		    Horst Hummel <Horst.Hummel@de.ibm.com>
4 *		    Carsten Otte <Cotte@de.ibm.com>
5 *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
6 * Bugreports.to..: <Linux390@de.ibm.com>
7 * Copyright IBM Corp. 1999, 2001
8 *
9 * gendisk related functions for the dasd driver.
10 *
11 */
12
13#define KMSG_COMPONENT "dasd"
14
15#include <linux/interrupt.h>
16#include <linux/fs.h>
17#include <linux/blkpg.h>
18
19#include <asm/uaccess.h>
20
21/* This is ugly... */
22#define PRINTK_HEADER "dasd_gendisk:"
23
24#include "dasd_int.h"
25
26/*
27 * Allocate and register gendisk structure for device.
28 */
29int dasd_gendisk_alloc(struct dasd_block *block)
30{
31	struct gendisk *gdp;
32	struct dasd_device *base;
33	int len;
34
35	/* Make sure the minor for this device exists. */
36	base = block->base;
37	if (base->devindex >= DASD_PER_MAJOR)
38		return -EBUSY;
39
40	gdp = alloc_disk(1 << DASD_PARTN_BITS);
41	if (!gdp)
42		return -ENOMEM;
43
44	/* Initialize gendisk structure. */
45	gdp->major = DASD_MAJOR;
46	gdp->first_minor = base->devindex << DASD_PARTN_BITS;
47	gdp->fops = &dasd_device_operations;
48	gdp->driverfs_dev = &base->cdev->dev;
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	add_disk(block->gdp);
80	return 0;
81}
82
83/*
84 * Unregister and free gendisk structure for device.
85 */
86void 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 */
99int dasd_scan_partitions(struct dasd_block *block)
100{
101	struct block_device *bdev;
102	int retry, rc;
103
104	retry = 5;
105	bdev = bdget_disk(block->gdp, 0);
106	if (!bdev) {
107		DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
108			      "scan partitions error, bdget returned NULL");
109		return -ENODEV;
110	}
111
112	rc = blkdev_get(bdev, FMODE_READ, NULL);
113	if (rc < 0) {
114		DBF_DEV_EVENT(DBF_ERR, block->base,
115			      "scan partitions error, blkdev_get returned %d",
116			      rc);
117		return -ENODEV;
118	}
119	/*
120	 * See fs/partition/check.c:register_disk,rescan_partitions
121	 * Can't call rescan_partitions directly. Use ioctl.
122	 */
123	rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
124	while (rc == -EBUSY && retry > 0) {
125		schedule();
126		rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
127		retry--;
128		DBF_DEV_EVENT(DBF_ERR, block->base,
129			      "scan partitions error, retry %d rc %d",
130			      retry, rc);
131	}
132
133	/*
134	 * Since the matching blkdev_put call to the blkdev_get in
135	 * this function is not called before dasd_destroy_partitions
136	 * the offline open_count limit needs to be increased from
137	 * 0 to 1. This is done by setting device->bdev (see
138	 * dasd_generic_set_offline). As long as the partition
139	 * detection is running no offline should be allowed. That
140	 * is why the assignment to device->bdev is done AFTER
141	 * the BLKRRPART ioctl.
142	 */
143	block->bdev = bdev;
144	return 0;
145}
146
147/*
148 * Remove all inodes in the system for a device, delete the
149 * partitions and make device unusable by setting its size to zero.
150 */
151void dasd_destroy_partitions(struct dasd_block *block)
152{
153	/* The two structs have 168/176 byte on 31/64 bit. */
154	struct blkpg_partition bpart;
155	struct blkpg_ioctl_arg barg;
156	struct block_device *bdev;
157
158	/*
159	 * Get the bdev pointer from the device structure and clear
160	 * device->bdev to lower the offline open_count limit again.
161	 */
162	bdev = block->bdev;
163	block->bdev = NULL;
164
165	/*
166	 * See fs/partition/check.c:delete_partition
167	 * Can't call delete_partitions directly. Use ioctl.
168	 * The ioctl also does locking and invalidation.
169	 */
170	memset(&bpart, 0, sizeof(struct blkpg_partition));
171	memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
172	barg.data = (void __force __user *) &bpart;
173	barg.op = BLKPG_DEL_PARTITION;
174	for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
175		ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
176
177	invalidate_partition(block->gdp, 0);
178	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
179	blkdev_put(bdev, FMODE_READ);
180	set_capacity(block->gdp, 0);
181}
182
183int dasd_gendisk_init(void)
184{
185	int rc;
186
187	/* Register to static dasd major 94 */
188	rc = register_blkdev(DASD_MAJOR, "dasd");
189	if (rc != 0) {
190		pr_warning("Registering the device driver with major number "
191			   "%d failed\n", DASD_MAJOR);
192		return rc;
193	}
194	return 0;
195}
196
197void dasd_gendisk_exit(void)
198{
199	unregister_blkdev(DASD_MAJOR, "dasd");
200}
201