summaryrefslogtreecommitdiff
path: root/linux/dev/drivers/block/genhd.c
blob: 3946b39ce1af76d26ac5e1d2648c2c56234aed8d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
/*
 *  Code extracted from
 *  linux/kernel/hd.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *
 *  Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
 *  in the early extended-partition checks and added DM partitions
 *
 *  Support for DiskManager v6.0x added by Mark Lord,
 *  with information provided by OnTrack.  This now works for linux fdisk
 *  and LILO, as well as loadlin and bootln.  Note that disks other than
 *  /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1).
 *
 *  More flexible handling of extended partitions - aeb, 950831
 *
 *  Check partition table on IDE disks for common CHS translations
 */

#include <linux/config.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/string.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif

#include <asm/system.h>

/*
 * Many architectures don't like unaligned accesses, which is
 * frequently the case with the nr_sects and start_sect partition
 * table entries.
 */
#include <asm/unaligned.h>

#ifdef MACH
#include <machine/spl.h>
#endif

#define SYS_IND(p)	get_unaligned(&p->sys_ind)
#define NR_SECTS(p)	get_unaligned(&p->nr_sects)
#define START_SECT(p)	get_unaligned(&p->start_sect)


struct gendisk *gendisk_head = NULL;

static int current_minor = 0;
extern int *blk_size[];
extern void rd_load(void);
extern void initrd_load(void);

extern int chr_dev_init(void);
extern int blk_dev_init(void);
extern int scsi_dev_init(void);
extern int net_dev_init(void);

/*
 * disk_name() is used by genhd.c and md.c.
 * It formats the devicename of the indicated disk
 * into the supplied buffer, and returns a pointer
 * to that same buffer (for convenience).
 */
char *disk_name (struct gendisk *hd, int minor, char *buf)
{
	unsigned int part;
	const char *maj = hd->major_name;
#ifdef MACH
	char unit = (minor >> hd->minor_shift) + '0';
#else
	char unit = (minor >> hd->minor_shift) + 'a';
#endif

#ifdef CONFIG_BLK_DEV_IDE
	/*
	 * IDE devices use multiple major numbers, but the drives
	 * are named as:  {hda,hdb}, {hdc,hdd}, {hde,hdf}, {hdg,hdh}..
	 * This requires special handling here.
	 */
	switch (hd->major) {
		case IDE3_MAJOR:
			unit += 2;
		case IDE2_MAJOR:
			unit += 2;
		case IDE1_MAJOR:
			unit += 2;
		case IDE0_MAJOR:
			maj = "hd";
	}
#endif
	part = minor & ((1 << hd->minor_shift) - 1);
	if (part)
#ifdef MACH
		sprintf(buf, "%s%cs%d", maj, unit, part);
#else
		sprintf(buf, "%s%c%d", maj, unit, part);
#endif
	else
		sprintf(buf, "%s%c", maj, unit);
	return buf;
}

static void add_partition (struct gendisk *hd, int minor, int start, int size)
{
	char buf[8];
	hd->part[minor].start_sect = start;
	hd->part[minor].nr_sects   = size;
	printk(" %s", disk_name(hd, minor, buf));
}

#if defined (MACH) && defined (CONFIG_BSD_DISKLABEL)
static int mach_minor;
static void
add_bsd_partition (struct gendisk *hd, int minor, int slice,
		   int start, int size)
{
  char buf[16];
  hd->part[minor].start_sect = start;
  hd->part[minor].nr_sects = size;
  printk (" %s%c", disk_name (hd, mach_minor, buf), slice);
}
#endif

static inline int is_extended_partition(struct partition *p)
{
	return (SYS_IND(p) == DOS_EXTENDED_PARTITION ||
		SYS_IND(p) == WIN98_EXTENDED_PARTITION ||
		SYS_IND(p) == LINUX_EXTENDED_PARTITION);
}

#ifdef CONFIG_MSDOS_PARTITION
/*
 * Create devices for each logical partition in an extended partition.
 * The logical partitions form a linked list, with each entry being
 * a partition table with two entries.  The first entry
 * is the real data partition (with a start relative to the partition
 * table start).  The second is a pointer to the next logical partition
 * (with a start relative to the entire extended partition).
 * We do not create a Linux partition for the partition tables, but
 * only for the actual data partitions.
 */

static void extended_partition(struct gendisk *hd, kdev_t dev)
{
	struct buffer_head *bh;
	struct partition *p;
	unsigned long first_sector, first_size, this_sector, this_size;
	int mask = (1 << hd->minor_shift) - 1;
	int i;

	first_sector = hd->part[MINOR(dev)].start_sect;
	first_size = hd->part[MINOR(dev)].nr_sects;
	this_sector = first_sector;

	while (1) {
		if ((current_minor & mask) == 0)
			return;
		if (!(bh = bread(dev,0,1024)))
			return;
	  /*
	   * This block is from a device that we're about to stomp on.
	   * So make sure nobody thinks this block is usable.
	   */
		bh->b_state = 0;

		if (*(unsigned short *) (bh->b_data+510) != 0xAA55)
			goto done;

		p = (struct partition *) (0x1BE + bh->b_data);

		this_size = hd->part[MINOR(dev)].nr_sects;

		/*
		 * Usually, the first entry is the real data partition,
		 * the 2nd entry is the next extended partition, or empty,
		 * and the 3rd and 4th entries are unused.
		 * However, DRDOS sometimes has the extended partition as
		 * the first entry (when the data partition is empty),
		 * and OS/2 seems to use all four entries.
		 */

		/*
		 * First process the data partition(s)
		 */
		for (i=0; i<4; i++, p++) {
		    if (!NR_SECTS(p) || is_extended_partition(p))
		      continue;

		    /* Check the 3rd and 4th entries -
		       these sometimes contain random garbage */
		    if (i >= 2
			&& START_SECT(p) + NR_SECTS(p) > this_size
			&& (this_sector + START_SECT(p) < first_sector ||
			    this_sector + START_SECT(p) + NR_SECTS(p) >
			     first_sector + first_size))
		      continue;

		    add_partition(hd, current_minor, this_sector+START_SECT(p), NR_SECTS(p));
		    current_minor++;
		    if ((current_minor & mask) == 0)
		      goto done;
		}
		/*
		 * Next, process the (first) extended partition, if present.
		 * (So far, there seems to be no reason to make
		 *  extended_partition()  recursive and allow a tree
		 *  of extended partitions.)
		 * It should be a link to the next logical partition.
		 * Create a minor for this just long enough to get the next
		 * partition table.  The minor will be reused for the next
		 * data partition.
		 */
		p -= 4;
		for (i=0; i<4; i++, p++)
		  if(NR_SECTS(p) && is_extended_partition(p))
		    break;
		if (i == 4)
		  goto done;	 /* nothing left to do */

		hd->part[current_minor].nr_sects = NR_SECTS(p);
		hd->part[current_minor].start_sect = first_sector + START_SECT(p);
		this_sector = first_sector + START_SECT(p);
		dev = MKDEV(hd->major, current_minor);
		brelse(bh);
	}
done:
	brelse(bh);
}

#ifdef CONFIG_BSD_DISKLABEL
/*
 * Create devices for BSD partitions listed in a disklabel, under a
 * dos-like partition. See extended_partition() for more information.
 */
static void bsd_disklabel_partition(struct gendisk *hd, kdev_t dev)
{
	struct buffer_head *bh;
	struct bsd_disklabel *l;
	struct bsd_partition *p;
	int mask = (1 << hd->minor_shift) - 1;

	if (!(bh = bread(dev,0,1024)))
		return;
	bh->b_state = 0;
	l = (struct bsd_disklabel *) (bh->b_data+512);
	if (l->d_magic != BSD_DISKMAGIC) {
		brelse(bh);
		return;
	}

	p = &l->d_partitions[0];
	while (p - &l->d_partitions[0] <= BSD_MAXPARTITIONS) {
		if ((current_minor & mask) >= (4 + hd->max_p))
			break;

		if (p->p_fstype != BSD_FS_UNUSED) {
#ifdef MACH
		  add_bsd_partition (hd, current_minor,
				     p - &l->d_partitions[0] + 'a',
				     p->p_offset, p->p_size);
#else
			add_partition(hd, current_minor, p->p_offset, p->p_size);
#endif
			current_minor++;
		}
		p++;
	}
	brelse(bh);

}
#endif

static int msdos_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector)
{
	int i, minor = current_minor;
	struct buffer_head *bh;
	struct partition *p;
	unsigned char *data;
	int mask = (1 << hd->minor_shift) - 1;
#ifdef CONFIG_BLK_DEV_IDE
	int tested_for_xlate = 0;

read_mbr:
#endif
	if (!(bh = bread(dev,0,1024))) {
		printk(" unable to read partition table\n");
		return -1;
	}
	data = bh->b_data;
	/* In some cases we modify the geometry    */
	/*  of the drive (below), so ensure that   */
	/*  nobody else tries to re-use this data. */
	bh->b_state = 0;
#ifdef CONFIG_BLK_DEV_IDE
check_table:
#endif
	if (*(unsigned short *)  (0x1fe + data) != 0xAA55) {
		brelse(bh);
		return 0;
	}
	p = (struct partition *) (0x1be + data);

#ifdef CONFIG_BLK_DEV_IDE
	if (!tested_for_xlate++) {	/* Do this only once per disk */
		/*
		 * Look for various forms of IDE disk geometry translation
		 */
		extern int ide_xlate_1024(kdev_t, int, const char *);
		unsigned int sig = *(unsigned short *)(data + 2);
		if (SYS_IND(p) == EZD_PARTITION) {
			/*
			 * The remainder of the disk must be accessed using
			 * a translated geometry that reduces the number of
			 * apparent cylinders to less than 1024 if possible.
			 *
			 * ide_xlate_1024() will take care of the necessary
			 * adjustments to fool fdisk/LILO and partition check.
			 */
			if (ide_xlate_1024(dev, -1, " [EZD]")) {
				data += 512;
				goto check_table;
			}
		} else if (SYS_IND(p) == DM6_PARTITION) {

			/*
			 * Everything on the disk is offset by 63 sectors,
			 * including a "new" MBR with its own partition table,
			 * and the remainder of the disk must be accessed using
			 * a translated geometry that reduces the number of
			 * apparent cylinders to less than 1024 if possible.
			 *
			 * ide_xlate_1024() will take care of the necessary
			 * adjustments to fool fdisk/LILO and partition check.
			 */
			if (ide_xlate_1024(dev, 1, " [DM6:DDO]")) {
				brelse(bh);
				goto read_mbr;	/* start over with new MBR */
			}
		} else if (sig <= 0x1ae && *(unsigned short *)(data + sig) == 0x55AA
			 && (1 & *(unsigned char *)(data + sig + 2)) )
		{
			/*
			 * DM6 signature in MBR, courtesy of OnTrack
			 */
			(void) ide_xlate_1024 (dev, 0, " [DM6:MBR]");
		} else if (SYS_IND(p) == DM6_AUX1PARTITION || SYS_IND(p) == DM6_AUX3PARTITION) {
			/*
			 * DM6 on other than the first (boot) drive
			 */
			(void) ide_xlate_1024(dev, 0, " [DM6:AUX]");
		} else {
			/*
			 * Examine the partition table for common translations.
			 * This is necessary for drives for situations where
			 * the translated geometry is unavailable from the BIOS.
			 */
			for (i = 0; i < 4 ; i++) {
				struct partition *q = &p[i];
				if (NR_SECTS(q)
				   && (q->sector & 63) == 1
				   && (q->end_sector & 63) == 63) {
					unsigned int heads = q->end_head + 1;
					if (heads == 32 || heads == 64 || heads == 128 || heads == 255) {

						(void) ide_xlate_1024(dev, heads, " [PTBL]");
						break;
					}
				}
			}
		}
	}
#endif	/* CONFIG_BLK_DEV_IDE */

	current_minor += 4;  /* first "extra" minor (for extended partitions) */
	for (i=1 ; i<=4 ; minor++,i++,p++) {
		if (!NR_SECTS(p))
			continue;
		add_partition(hd, minor, first_sector+START_SECT(p), NR_SECTS(p));
		if (is_extended_partition(p)) {
			printk(" <");
			/*
			 * If we are rereading the partition table, we need
			 * to set the size of the partition so that we will
			 * be able to bread the block containing the extended
			 * partition info.
			 */
			hd->sizes[minor] = hd->part[minor].nr_sects
			  	>> (BLOCK_SIZE_BITS - 9);
			extended_partition(hd, MKDEV(hd->major, minor));
			printk(" >");
			/* prevent someone doing mkfs or mkswap on an
			   extended partition, but leave room for LILO */
			if (hd->part[minor].nr_sects > 2)
				hd->part[minor].nr_sects = 2;
		}
#ifdef CONFIG_BSD_DISKLABEL
		if (SYS_IND(p) == BSD_PARTITION) {
			printk(" <");
#ifdef MACH
			mach_minor = minor;
#endif
			bsd_disklabel_partition(hd, MKDEV(hd->major, minor));
			printk(" >");
		}
#endif
	}
	/*
	 *  Check for old-style Disk Manager partition table
	 */
	if (*(unsigned short *) (data+0xfc) == 0x55AA) {
		p = (struct partition *) (0x1be + data);
		for (i = 4 ; i < 16 ; i++, current_minor++) {
			p--;
			if ((current_minor & mask) == 0)
				break;
			if (!(START_SECT(p) && NR_SECTS(p)))
				continue;
			add_partition(hd, current_minor, START_SECT(p), NR_SECTS(p));
		}
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif /* CONFIG_MSDOS_PARTITION */

#ifdef CONFIG_OSF_PARTITION

static int osf_partition(struct gendisk *hd, unsigned int dev, unsigned long first_sector)
{
	int i;
	int mask = (1 << hd->minor_shift) - 1;
	struct buffer_head *bh;
	struct disklabel {
		u32 d_magic;
		u16 d_type,d_subtype;
		u8 d_typename[16];
		u8 d_packname[16];
		u32 d_secsize;
		u32 d_nsectors;
		u32 d_ntracks;
		u32 d_ncylinders;
		u32 d_secpercyl;
		u32 d_secprtunit;
		u16 d_sparespertrack;
		u16 d_sparespercyl;
		u32 d_acylinders;
		u16 d_rpm, d_interleave, d_trackskew, d_cylskew;
		u32 d_headswitch, d_trkseek, d_flags;
		u32 d_drivedata[5];
		u32 d_spare[5];
		u32 d_magic2;
		u16 d_checksum;
		u16 d_npartitions;
		u32 d_bbsize, d_sbsize;
		struct d_partition {
			u32 p_size;
			u32 p_offset;
			u32 p_fsize;
			u8  p_fstype;
			u8  p_frag;
			u16 p_cpg;
		} d_partitions[8];
	} * label;
	struct d_partition * partition;
#define DISKLABELMAGIC (0x82564557UL)

	if (!(bh = bread(dev,0,1024))) {
		printk("unable to read partition table\n");
		return -1;
	}
	label = (struct disklabel *) (bh->b_data+64);
	partition = label->d_partitions;
	if (label->d_magic != DISKLABELMAGIC) {
		printk("magic: %08x\n", label->d_magic);
		brelse(bh);
		return 0;
	}
	if (label->d_magic2 != DISKLABELMAGIC) {
		printk("magic2: %08x\n", label->d_magic2);
		brelse(bh);
		return 0;
	}
	for (i = 0 ; i < label->d_npartitions; i++, partition++) {
		if ((current_minor & mask) == 0)
		        break;
		if (partition->p_size)
			add_partition(hd, current_minor,
				first_sector+partition->p_offset,
				partition->p_size);
		current_minor++;
	}
	printk("\n");
	brelse(bh);
	return 1;
}

#endif /* CONFIG_OSF_PARTITION */

#ifdef CONFIG_SUN_PARTITION

static int sun_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector)
{
	int i, csum;
	unsigned short *ush;
	struct buffer_head *bh;
	struct sun_disklabel {
		unsigned char info[128];   /* Informative text string */
		unsigned char spare[292];  /* Boot information etc. */
		unsigned short rspeed;     /* Disk rotational speed */
		unsigned short pcylcount;  /* Physical cylinder count */
		unsigned short sparecyl;   /* extra sects per cylinder */
		unsigned char spare2[4];   /* More magic... */
		unsigned short ilfact;     /* Interleave factor */
		unsigned short ncyl;       /* Data cylinder count */
		unsigned short nacyl;      /* Alt. cylinder count */
		unsigned short ntrks;      /* Tracks per cylinder */
		unsigned short nsect;      /* Sectors per track */
		unsigned char spare3[4];   /* Even more magic... */
		struct sun_partition {
			__u32 start_cylinder;
			__u32 num_sectors;
		} partitions[8];
		unsigned short magic;      /* Magic number */
		unsigned short csum;       /* Label xor'd checksum */
	} * label;
	struct sun_partition *p;
	int other_endian;
	unsigned long spc;
#define SUN_LABEL_MAGIC          0xDABE
#define SUN_LABEL_MAGIC_SWAPPED  0xBEDA
/* No need to optimize these macros since they are called only when reading
 * the partition table. This occurs only at each disk change. */
#define SWAP16(x)  (other_endian ? (((__u16)(x) & 0xFF) << 8) \
				 | (((__u16)(x) & 0xFF00) >> 8) \
				 : (__u16)(x))
#define SWAP32(x)  (other_endian ? (((__u32)(x) & 0xFF) << 24) \
				 | (((__u32)(x) & 0xFF00) << 8) \
				 | (((__u32)(x) & 0xFF0000) >> 8) \
				 | (((__u32)(x) & 0xFF000000) >> 24) \
				 : (__u32)(x))

	if(!(bh = bread(dev, 0, 1024))) {
		printk("Dev %s: unable to read partition table\n",
		       kdevname(dev));
		return -1;
	}
	label = (struct sun_disklabel *) bh->b_data;
	p = label->partitions;
	if (label->magic != SUN_LABEL_MAGIC && label->magic != SUN_LABEL_MAGIC_SWAPPED) {
		printk("Dev %s Sun disklabel: bad magic %04x\n",
		       kdevname(dev), label->magic);
		brelse(bh);
		return 0;
	}
	other_endian = (label->magic == SUN_LABEL_MAGIC_SWAPPED);
	/* Look at the checksum */
	ush = ((unsigned short *) (label+1)) - 1;
	for(csum = 0; ush >= ((unsigned short *) label);)
		csum ^= *ush--;
	if(csum) {
		printk("Dev %s Sun disklabel: Csum bad, label corrupted\n",
		       kdevname(dev));
		brelse(bh);
		return 0;
	}
	/* All Sun disks have 8 partition entries */
	spc = SWAP16(label->ntrks) * SWAP16(label->nsect);
	for(i=0; i < 8; i++, p++) {
		unsigned long st_sector;

		/* We register all partitions, even if zero size, so that
		 * the minor numbers end up ok as per SunOS interpretation.
		 */
		st_sector = first_sector + SWAP32(p->start_cylinder) * spc;
		add_partition(hd, current_minor, st_sector, SWAP32(p->num_sectors));
		current_minor++;
	}
	printk("\n");
	brelse(bh);
	return 1;
#undef SWAP16
#undef SWAP32
}

#endif /* CONFIG_SUN_PARTITION */

#ifdef CONFIG_AMIGA_PARTITION
#include <asm/byteorder.h>
#include <linux/affs_hardblocks.h>

static __inline__ __u32
checksum_block(__u32 *m, int size)
{
	__u32 sum = 0;

	while (size--)
		sum += htonl(*m++);
	return sum;
}

static int
amiga_partition(struct gendisk *hd, unsigned int dev, unsigned long first_sector)
{
	struct buffer_head	*bh;
	struct RigidDiskBlock	*rdb;
	struct PartitionBlock	*pb;
	int			 start_sect;
	int			 nr_sects;
	int			 blk;
	int			 part, res;

	set_blocksize(dev,512);
	res = 0;

	for (blk = 0; blk < RDB_ALLOCATION_LIMIT; blk++) {
		if(!(bh = bread(dev,blk,512))) {
			printk("Dev %d: unable to read RDB block %d\n",dev,blk);
			goto rdb_done;
		}
		if (*(__u32 *)bh->b_data == htonl(IDNAME_RIGIDDISK)) {
			rdb = (struct RigidDiskBlock *)bh->b_data;
			if (checksum_block((__u32 *)bh->b_data,htonl(rdb->rdb_SummedLongs) & 0x7F)) {
				printk("Dev %d: RDB in block %d has bad checksum\n",dev,blk);
				brelse(bh);
				continue;
			}
			printk(" RDSK");
			blk = htonl(rdb->rdb_PartitionList);
			brelse(bh);
			for (part = 1; blk > 0 && part <= 16; part++) {
				if (!(bh = bread(dev,blk,512))) {
					printk("Dev %d: unable to read partition block %d\n",
						       dev,blk);
					goto rdb_done;
				}
				pb  = (struct PartitionBlock *)bh->b_data;
				blk = htonl(pb->pb_Next);
				if (pb->pb_ID == htonl(IDNAME_PARTITION) && checksum_block(
				    (__u32 *)pb,htonl(pb->pb_SummedLongs) & 0x7F) == 0 ) {

					/* Tell Kernel about it */

					if (!(nr_sects = (htonl(pb->pb_Environment[10]) + 1 -
							  htonl(pb->pb_Environment[9])) *
							 htonl(pb->pb_Environment[3]) *
							 htonl(pb->pb_Environment[5]))) {
						continue;
					}
					start_sect = htonl(pb->pb_Environment[9]) *
						     htonl(pb->pb_Environment[3]) *
						     htonl(pb->pb_Environment[5]);
					add_partition(hd,current_minor,start_sect,nr_sects);
					current_minor++;
					res = 1;
				}
				brelse(bh);
			}
			printk("\n");
			break;
		}
	}

rdb_done:
	set_blocksize(dev,BLOCK_SIZE);
	return res;
}
#endif /* CONFIG_AMIGA_PARTITION */

static void check_partition(struct gendisk *hd, kdev_t dev)
{
	static int first_time = 1;
	unsigned long first_sector;
	char buf[8];

	if (first_time)
		printk("Partition check (DOS partitions):\n");
	first_time = 0;
	first_sector = hd->part[MINOR(dev)].start_sect;

	/*
	 * This is a kludge to allow the partition check to be
	 * skipped for specific drives (e.g. IDE cd-rom drives)
	 */
	if ((int)first_sector == -1) {
		hd->part[MINOR(dev)].start_sect = 0;
		return;
	}

	printk(" %s:", disk_name(hd, MINOR(dev), buf));
#ifdef CONFIG_MSDOS_PARTITION
	if (msdos_partition(hd, dev, first_sector))
		return;
#endif
#ifdef CONFIG_OSF_PARTITION
	if (osf_partition(hd, dev, first_sector))
		return;
#endif
#ifdef CONFIG_SUN_PARTITION
	if(sun_partition(hd, dev, first_sector))
		return;
#endif
#ifdef CONFIG_AMIGA_PARTITION
	if(amiga_partition(hd, dev, first_sector))
		return;
#endif
	printk(" unknown partition table\n");
}

/* This function is used to re-read partition tables for removable disks.
   Much of the cleanup from the old partition tables should have already been
   done */

/* This function will re-read the partition tables for a given device,
and set things back up again.  There are some important caveats,
however.  You must ensure that no one is using the device, and no one
can start using the device while this function is being executed. */

void resetup_one_dev(struct gendisk *dev, int drive)
{
	int i;
	int first_minor	= drive << dev->minor_shift;
	int end_minor	= first_minor + dev->max_p;

	blk_size[dev->major] = NULL;
	current_minor = 1 + first_minor;
	check_partition(dev, MKDEV(dev->major, first_minor));

 	/*
 	 * We need to set the sizes array before we will be able to access
 	 * any of the partitions on this device.
 	 */
	if (dev->sizes != NULL) {	/* optional safeguard in ll_rw_blk.c */
		for (i = first_minor; i < end_minor; i++)
			dev->sizes[i] = dev->part[i].nr_sects >> (BLOCK_SIZE_BITS - 9);
		blk_size[dev->major] = dev->sizes;
	}
}

static void setup_dev(struct gendisk *dev)
{
	int i, drive;
	int end_minor	= dev->max_nr * dev->max_p;

	blk_size[dev->major] = NULL;
	for (i = 0 ; i < end_minor; i++) {
		dev->part[i].start_sect = 0;
		dev->part[i].nr_sects = 0;
	}
	dev->init(dev);
	for (drive = 0 ; drive < dev->nr_real ; drive++) {
		int first_minor	= drive << dev->minor_shift;
		current_minor = 1 + first_minor;
		check_partition(dev, MKDEV(dev->major, first_minor));
	}
	if (dev->sizes != NULL) {	/* optional safeguard in ll_rw_blk.c */
		for (i = 0; i < end_minor; i++)
			dev->sizes[i] = dev->part[i].nr_sects >> (BLOCK_SIZE_BITS - 9);
		blk_size[dev->major] = dev->sizes;
	}
}

void device_setup(void)
{
	extern void console_map_init(void);
	struct gendisk *p;
	int nr=0;
#ifdef MACH
	extern int linux_intr_pri;

	linux_intr_pri = SPL5;
#endif

#ifndef MACH
	chr_dev_init();
#endif
	blk_dev_init();
	sti();
#ifdef CONFIG_SCSI
	scsi_dev_init();
#endif
#ifdef CONFIG_INET
#ifdef MACH
	linux_intr_pri = SPL6;
#endif
	net_dev_init();
#endif
#ifndef MACH
	console_map_init();
#endif

	for (p = gendisk_head ; p ; p=p->next) {
		setup_dev(p);
		nr += p->nr_real;
	}
#ifdef CONFIG_BLK_DEV_RAM
#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start && mount_initrd) initrd_load();
	else
#endif
	rd_load();
#endif
}