sd.c 46.5 KB
Newer Older
L
Linus Torvalds 已提交
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
/*
 *      sd.c Copyright (C) 1992 Drew Eckhardt
 *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
 *
 *      Linux scsi disk driver
 *              Initial versions: Drew Eckhardt
 *              Subsequent revisions: Eric Youngdale
 *	Modification history:
 *       - Drew Eckhardt <drew@colorado.edu> original
 *       - Eric Youngdale <eric@andante.org> add scatter-gather, multiple 
 *         outstanding request, and other enhancements.
 *         Support loadable low-level scsi drivers.
 *       - Jirka Hanika <geo@ff.cuni.cz> support more scsi disks using 
 *         eight major numbers.
 *       - Richard Gooch <rgooch@atnf.csiro.au> support devfs.
 *	 - Torben Mathiasen <tmm@image.dk> Resource allocation fixes in 
 *	   sd_init and cleanups.
 *	 - Alex Davis <letmein@erols.com> Fix problem where partition info
 *	   not being read in sd_open. Fix problem where removable media 
 *	   could be ejected after sd_open.
 *	 - Douglas Gilbert <dgilbert@interlog.com> cleanup for lk 2.5.x
 *	 - Badari Pulavarty <pbadari@us.ibm.com>, Matthew Wilcox 
 *	   <willy@debian.org>, Kurt Garloff <garloff@suse.de>: 
 *	   Support 32k/1M disks.
 *
 *	Logging policy (needs CONFIG_SCSI_LOGGING defined):
 *	 - setting up transfer: SCSI_LOG_HLQUEUE levels 1 and 2
 *	 - end of transfer (bh + scsi_lib): SCSI_LOG_HLCOMPLETE level 1
 *	 - entering sd_ioctl: SCSI_LOG_IOCTL level 1
 *	 - entering other commands: SCSI_LOG_HLQUEUE level 3
 *	Note: when the logging level is set by the user, it must be greater
 *	than the level indicated above to trigger output.	
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/genhd.h>
#include <linux/hdreg.h>
#include <linux/errno.h>
#include <linux/idr.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/kref.h>
#include <linux/delay.h>
#include <asm/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsicam.h>

#include "scsi_logging.h"

/*
 * More than enough for everybody ;)  The huge number of majors
 * is a leftover from 16bit dev_t days, we don't really need that
 * much numberspace.
 */
#define SD_MAJORS	16

/*
 * This is limited by the naming scheme enforced in sd_probe,
 * add another character to it if you really need more disks.
 */
#define SD_MAX_DISKS	(((26 * 26) + 26 + 1) * 26)

/*
 * Time out in seconds for disks and Magneto-opticals (which are slower).
 */
#define SD_TIMEOUT		(30 * HZ)
#define SD_MOD_TIMEOUT		(75 * HZ)

/*
 * Number of allowed retries
 */
#define SD_MAX_RETRIES		5
#define SD_PASSTHROUGH_RETRIES	1

static void scsi_disk_release(struct kref *kref);

struct scsi_disk {
	struct scsi_driver *driver;	/* always &sd_template */
	struct scsi_device *device;
	struct kref	kref;
	struct gendisk	*disk;
	unsigned int	openers;	/* protected by BKL for now, yuck */
	sector_t	capacity;	/* size in 512-byte sectors */
	u32		index;
	u8		media_present;
	u8		write_prot;
	unsigned	WCE : 1;	/* state of disk WCE bit */
	unsigned	RCD : 1;	/* state of disk RCD bit, unused */
};

static DEFINE_IDR(sd_index_idr);
static DEFINE_SPINLOCK(sd_index_lock);

/* This semaphore is used to mediate the 0->1 reference get in the
 * face of object destruction (i.e. we can't allow a get on an
 * object after last put) */
static DECLARE_MUTEX(sd_ref_sem);

static int sd_revalidate_disk(struct gendisk *disk);
static void sd_rw_intr(struct scsi_cmnd * SCpnt);

static int sd_probe(struct device *);
static int sd_remove(struct device *);
static void sd_shutdown(struct device *dev);
static void sd_rescan(struct device *);
static int sd_init_command(struct scsi_cmnd *);
static int sd_issue_flush(struct device *, sector_t *);
static void sd_end_flush(request_queue_t *, struct request *);
static int sd_prepare_flush(request_queue_t *, struct request *);
static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
127
			     unsigned char *buffer);
L
Linus Torvalds 已提交
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

static struct scsi_driver sd_template = {
	.owner			= THIS_MODULE,
	.gendrv = {
		.name		= "sd",
		.probe		= sd_probe,
		.remove		= sd_remove,
		.shutdown	= sd_shutdown,
	},
	.rescan			= sd_rescan,
	.init_command		= sd_init_command,
	.issue_flush		= sd_issue_flush,
	.prepare_flush		= sd_prepare_flush,
	.end_flush		= sd_end_flush,
};

/*
 * Device no to disk mapping:
 * 
 *       major         disc2     disc  p1
 *   |............|.............|....|....| <- dev_t
 *    31        20 19          8 7  4 3  0
 * 
 * Inside a major, we have 16k disks, however mapped non-
 * contiguously. The first 16 disks are for major0, the next
 * ones with major1, ... Disk 256 is for major0 again, disk 272 
 * for major1, ... 
 * As we stay compatible with our numbering scheme, we can reuse 
 * the well-know SCSI majors 8, 65--71, 136--143.
 */
static int sd_major(int major_idx)
{
	switch (major_idx) {
	case 0:
		return SCSI_DISK0_MAJOR;
	case 1 ... 7:
		return SCSI_DISK1_MAJOR + major_idx - 1;
	case 8 ... 15:
		return SCSI_DISK8_MAJOR + major_idx - 8;
	default:
		BUG();
		return 0;	/* shut up gcc */
	}
}

#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,kref)

static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
{
	return container_of(disk->private_data, struct scsi_disk, driver);
}

static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
{
	struct scsi_disk *sdkp = NULL;

	down(&sd_ref_sem);
	if (disk->private_data == NULL)
		goto out;
	sdkp = scsi_disk(disk);
	kref_get(&sdkp->kref);
	if (scsi_device_get(sdkp->device))
		goto out_put;
	up(&sd_ref_sem);
	return sdkp;

 out_put:
	kref_put(&sdkp->kref, scsi_disk_release);
	sdkp = NULL;
 out:
	up(&sd_ref_sem);
	return sdkp;
}

static void scsi_disk_put(struct scsi_disk *sdkp)
{
	struct scsi_device *sdev = sdkp->device;

	down(&sd_ref_sem);
	kref_put(&sdkp->kref, scsi_disk_release);
	scsi_device_put(sdev);
	up(&sd_ref_sem);
}

/**
 *	sd_init_command - build a scsi (read or write) command from
 *	information in the request structure.
 *	@SCpnt: pointer to mid-level's per scsi command structure that
 *	contains request and into which the scsi command is written
 *
 *	Returns 1 if successful and 0 if error (or cannot be done now).
 **/
static int sd_init_command(struct scsi_cmnd * SCpnt)
{
	unsigned int this_count, timeout;
	struct gendisk *disk;
	sector_t block;
	struct scsi_device *sdp = SCpnt->device;
	struct request *rq = SCpnt->request;

	timeout = sdp->timeout;

	/*
	 * SG_IO from block layer already setup, just copy cdb basically
	 */
	if (blk_pc_request(rq)) {
		if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd))
			return 0;

		memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd));
238
		SCpnt->cmd_len = rq->cmd_len;
L
Linus Torvalds 已提交
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
		if (rq_data_dir(rq) == WRITE)
			SCpnt->sc_data_direction = DMA_TO_DEVICE;
		else if (rq->data_len)
			SCpnt->sc_data_direction = DMA_FROM_DEVICE;
		else
			SCpnt->sc_data_direction = DMA_NONE;

		this_count = rq->data_len;
		if (rq->timeout)
			timeout = rq->timeout;

		SCpnt->transfersize = rq->data_len;
		SCpnt->allowed = SD_PASSTHROUGH_RETRIES;
		goto queue;
	}

	/*
	 * we only do REQ_CMD and REQ_BLOCK_PC
	 */
	if (!blk_fs_request(rq))
		return 0;

	disk = rq->rq_disk;
	block = rq->sector;
	this_count = SCpnt->request_bufflen >> 9;

	SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
			    "count=%d\n", disk->disk_name,
			 (unsigned long long)block, this_count));

	if (!sdp || !scsi_device_online(sdp) ||
 	    block + rq->nr_sectors > get_capacity(disk)) {
		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n", 
				 rq->nr_sectors));
		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
		return 0;
	}

	if (sdp->changed) {
		/*
		 * quietly refuse to do anything to a changed disc until 
		 * the changed bit has been reset
		 */
		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
		return 0;
	}
	SCSI_LOG_HLQUEUE(2, printk("%s : block=%llu\n",
				   disk->disk_name, (unsigned long long)block));

	/*
	 * If we have a 1K hardware sectorsize, prevent access to single
	 * 512 byte sectors.  In theory we could handle this - in fact
	 * the scsi cdrom driver must be able to handle this because
	 * we typically use 1K blocksizes, and cdroms typically have
	 * 2K hardware sectorsizes.  Of course, things are simpler
	 * with the cdrom, since it is read-only.  For performance
	 * reasons, the filesystems should be able to handle this
	 * and not force the scsi disk driver to use bounce buffers
	 * for this.
	 */
	if (sdp->sector_size == 1024) {
		if ((block & 1) || (rq->nr_sectors & 1)) {
			printk(KERN_ERR "sd: Bad block number requested");
			return 0;
		} else {
			block = block >> 1;
			this_count = this_count >> 1;
		}
	}
	if (sdp->sector_size == 2048) {
		if ((block & 3) || (rq->nr_sectors & 3)) {
			printk(KERN_ERR "sd: Bad block number requested");
			return 0;
		} else {
			block = block >> 2;
			this_count = this_count >> 2;
		}
	}
	if (sdp->sector_size == 4096) {
		if ((block & 7) || (rq->nr_sectors & 7)) {
			printk(KERN_ERR "sd: Bad block number requested");
			return 0;
		} else {
			block = block >> 3;
			this_count = this_count >> 3;
		}
	}
	if (rq_data_dir(rq) == WRITE) {
		if (!sdp->writeable) {
			return 0;
		}
		SCpnt->cmnd[0] = WRITE_6;
		SCpnt->sc_data_direction = DMA_TO_DEVICE;
	} else if (rq_data_dir(rq) == READ) {
		SCpnt->cmnd[0] = READ_6;
		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
	} else {
		printk(KERN_ERR "sd: Unknown command %lx\n", rq->flags);
/* overkill 	panic("Unknown sd command %lx\n", rq->flags); */
		return 0;
	}

	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n", 
		disk->disk_name, (rq_data_dir(rq) == WRITE) ? 
		"writing" : "reading", this_count, rq->nr_sectors));

	SCpnt->cmnd[1] = 0;
	
	if (block > 0xffffffff) {
		SCpnt->cmnd[0] += READ_16 - READ_6;
		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
		   SCpnt->device->use_10_for_rw) {
		if (this_count > 0xffff)
			this_count = 0xffff;

		SCpnt->cmnd[0] += READ_10 - READ_6;
		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
	} else {
		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
		SCpnt->cmnd[4] = (unsigned char) this_count;
		SCpnt->cmnd[5] = 0;
	}
	SCpnt->request_bufflen = SCpnt->bufflen =
			this_count * sdp->sector_size;

	/*
	 * We shouldn't disconnect in the middle of a sector, so with a dumb
	 * host adapter, it's safe to assume that we can at least transfer
	 * this many bytes between each connect / disconnect.
	 */
	SCpnt->transfersize = sdp->sector_size;
	SCpnt->underflow = this_count << 9;
	SCpnt->allowed = SD_MAX_RETRIES;

queue:
	SCpnt->timeout_per_command = timeout;

	/*
	 * This is the completion routine we use.  This is matched in terms
	 * of capability to this function.
	 */
	SCpnt->done = sd_rw_intr;

	/*
	 * This indicates that the command is ready from our end to be
	 * queued.
	 */
	return 1;
}

/**
 *	sd_open - open a scsi disk device
 *	@inode: only i_rdev member may be used
 *	@filp: only f_mode and f_flags may be used
 *
 *	Returns 0 if successful. Returns a negated errno value in case 
 *	of error.
 *
 *	Note: This can be called from a user context (e.g. fsck(1) )
 *	or from within the kernel (e.g. as a result of a mount(1) ).
 *	In the latter case @inode and @filp carry an abridged amount
 *	of information as noted above.
 **/
static int sd_open(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct scsi_disk *sdkp;
	struct scsi_device *sdev;
	int retval;

	if (!(sdkp = scsi_disk_get(disk)))
		return -ENXIO;


	SCSI_LOG_HLQUEUE(3, printk("sd_open: disk=%s\n", disk->disk_name));

	sdev = sdkp->device;

	/*
	 * If the device is in error recovery, wait until it is done.
	 * If the device is offline, then disallow any access to it.
	 */
	retval = -ENXIO;
	if (!scsi_block_when_processing_errors(sdev))
		goto error_out;

	if (sdev->removable || sdkp->write_prot)
		check_disk_change(inode->i_bdev);

	/*
	 * If the drive is empty, just let the open fail.
	 */
	retval = -ENOMEDIUM;
	if (sdev->removable && !sdkp->media_present &&
	    !(filp->f_flags & O_NDELAY))
		goto error_out;

	/*
	 * If the device has the write protect tab set, have the open fail
	 * if the user expects to be able to write to the thing.
	 */
	retval = -EROFS;
	if (sdkp->write_prot && (filp->f_mode & FMODE_WRITE))
		goto error_out;

	/*
	 * It is possible that the disk changing stuff resulted in
	 * the device being taken offline.  If this is the case,
	 * report this to the user, and don't pretend that the
	 * open actually succeeded.
	 */
	retval = -ENXIO;
	if (!scsi_device_online(sdev))
		goto error_out;

	if (!sdkp->openers++ && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
	}

	return 0;

error_out:
	scsi_disk_put(sdkp);
	return retval;	
}

/**
 *	sd_release - invoked when the (last) close(2) is called on this
 *	scsi disk.
 *	@inode: only i_rdev member may be used
 *	@filp: only f_mode and f_flags may be used
 *
 *	Returns 0. 
 *
 *	Note: may block (uninterruptible) if error recovery is underway
 *	on this disk.
 **/
static int sd_release(struct inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdev = sdkp->device;

	SCSI_LOG_HLQUEUE(3, printk("sd_release: disk=%s\n", disk->disk_name));

	if (!--sdkp->openers && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
	}

	/*
	 * XXX and what if there are packets in flight and this close()
	 * XXX is followed by a "rmmod sd_mod"?
	 */
	scsi_disk_put(sdkp);
	return 0;
}

static int sd_hdio_getgeo(struct block_device *bdev, struct hd_geometry __user *loc)
{
	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
	struct scsi_device *sdp = sdkp->device;
	struct Scsi_Host *host = sdp->host;
	int diskinfo[4];

	/* default to most commonly used values */
        diskinfo[0] = 0x40;	/* 1 << 6 */
       	diskinfo[1] = 0x20;	/* 1 << 5 */
       	diskinfo[2] = sdkp->capacity >> 11;
	
	/* override with calculated, extended default, or driver values */
	if (host->hostt->bios_param)
		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
	else
		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);

	if (put_user(diskinfo[0], &loc->heads))
		return -EFAULT;
	if (put_user(diskinfo[1], &loc->sectors))
		return -EFAULT;
	if (put_user(diskinfo[2], &loc->cylinders))
		return -EFAULT;
	if (put_user((unsigned)get_start_sect(bdev),
	             (unsigned long __user *)&loc->start))
		return -EFAULT;
	return 0;
}

/**
 *	sd_ioctl - process an ioctl
 *	@inode: only i_rdev/i_bdev members may be used
 *	@filp: only f_mode and f_flags may be used
 *	@cmd: ioctl command number
 *	@arg: this is third argument given to ioctl(2) system call.
 *	Often contains a pointer.
 *
 *	Returns 0 if successful (some ioctls return postive numbers on
 *	success as well). Returns a negated errno value in case of error.
 *
 *	Note: most ioctls are forward onto the block subsystem or further
 *	down in the scsi subsytem.
 **/
static int sd_ioctl(struct inode * inode, struct file * filp, 
		    unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = inode->i_bdev;
	struct gendisk *disk = bdev->bd_disk;
	struct scsi_device *sdp = scsi_disk(disk)->device;
	void __user *p = (void __user *)arg;
	int error;
    
	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
						disk->disk_name, cmd));

	/*
	 * If we are in the middle of error recovery, don't let anyone
	 * else try and use this device.  Also, if error recovery fails, it
	 * may try and take the device offline, in which case all further
	 * access to the device is prohibited.
	 */
	error = scsi_nonblockable_ioctl(sdp, cmd, p, filp);
	if (!scsi_block_when_processing_errors(sdp) || !error)
		return error;

	if (cmd == HDIO_GETGEO) {
		if (!arg)
			return -EINVAL;
		return sd_hdio_getgeo(bdev, p);
	}

	/*
	 * Send SCSI addressing ioctls directly to mid level, send other
	 * ioctls to block level and then onto mid level if they can't be
	 * resolved.
	 */
	switch (cmd) {
		case SCSI_IOCTL_GET_IDLUN:
		case SCSI_IOCTL_GET_BUS_NUMBER:
			return scsi_ioctl(sdp, cmd, p);
		default:
			error = scsi_cmd_ioctl(filp, disk, cmd, p);
			if (error != -ENOTTY)
				return error;
	}
	return scsi_ioctl(sdp, cmd, p);
}

static void set_media_not_present(struct scsi_disk *sdkp)
{
	sdkp->media_present = 0;
	sdkp->capacity = 0;
	sdkp->device->changed = 1;
}

/**
 *	sd_media_changed - check if our medium changed
 *	@disk: kernel device descriptor 
 *
 *	Returns 0 if not applicable or no change; 1 if change
 *
 *	Note: this function is invoked from the block subsystem.
 **/
static int sd_media_changed(struct gendisk *disk)
{
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdp = sdkp->device;
	int retval;

	SCSI_LOG_HLQUEUE(3, printk("sd_media_changed: disk=%s\n",
						disk->disk_name));

	if (!sdp->removable)
		return 0;

	/*
	 * If the device is offline, don't send any commands - just pretend as
	 * if the command failed.  If the device ever comes back online, we
	 * can deal with it then.  It is only because of unrecoverable errors
	 * that we would ever take a device offline in the first place.
	 */
	if (!scsi_device_online(sdp))
		goto not_present;

	/*
	 * Using TEST_UNIT_READY enables differentiation between drive with
	 * no cartridge loaded - NOT READY, drive with changed cartridge -
	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
	 *
	 * Drives that auto spin down. eg iomega jaz 1G, will be started
	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
	 * sd_revalidate() is called.
	 */
	retval = -ENODEV;
	if (scsi_block_when_processing_errors(sdp))
		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);

	/*
	 * Unable to test, unit probably not ready.   This usually
	 * means there is no disc in the drive.  Mark as changed,
	 * and we will figure it out later once the drive is
	 * available again.
	 */
	if (retval)
		 goto not_present;

	/*
	 * For removable scsi disk we have to recognise the presence
	 * of a disk in the drive. This is kept in the struct scsi_disk
	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
	 */
	sdkp->media_present = 1;

	retval = sdp->changed;
	sdp->changed = 0;

	return retval;

not_present:
	set_media_not_present(sdkp);
	return 1;
}

static int sd_sync_cache(struct scsi_device *sdp)
{
	int retries, res;
686
	struct scsi_sense_hdr sshdr;
L
Linus Torvalds 已提交
687 688 689 690 691 692 693 694 695 696 697 698 699

	if (!scsi_device_online(sdp))
		return -ENODEV;


	for (retries = 3; retries > 0; --retries) {
		unsigned char cmd[10] = { 0 };

		cmd[0] = SYNCHRONIZE_CACHE;
		/*
		 * Leave the rest of the command zero to indicate
		 * flush everything.
		 */
700 701 702
		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
				       SD_TIMEOUT, SD_MAX_RETRIES);
		if (res == 0)
L
Linus Torvalds 已提交
703 704 705
			break;
	}

706
	if (res) {		printk(KERN_WARNING "FAILED\n  status = %x, message = %02x, "
L
Linus Torvalds 已提交
707 708 709 710
				    "host = %d, driver = %02x\n  ",
				    status_byte(res), msg_byte(res),
				    host_byte(res), driver_byte(res));
			if (driver_byte(res) & DRIVER_SENSE)
711
				scsi_print_sense_hdr("sd", &sshdr);
L
Linus Torvalds 已提交
712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951
	}

	return res;
}

static int sd_issue_flush(struct device *dev, sector_t *error_sector)
{
	struct scsi_device *sdp = to_scsi_device(dev);
	struct scsi_disk *sdkp = dev_get_drvdata(dev);

	if (!sdkp)
               return -ENODEV;

	if (!sdkp->WCE)
		return 0;

	return sd_sync_cache(sdp);
}

static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
{
	struct request *rq = flush_rq->end_io_data;
	struct scsi_cmnd *cmd = rq->special;
	unsigned int bytes = rq->hard_nr_sectors << 9;

	if (!flush_rq->errors) {
		spin_unlock(q->queue_lock);
		scsi_io_completion(cmd, bytes, 0);
		spin_lock(q->queue_lock);
	} else if (blk_barrier_postflush(rq)) {
		spin_unlock(q->queue_lock);
		scsi_io_completion(cmd, 0, bytes);
		spin_lock(q->queue_lock);
	} else {
		/*
		 * force journal abort of barriers
		 */
		end_that_request_first(rq, -EOPNOTSUPP, rq->hard_nr_sectors);
		end_that_request_last(rq);
	}
}

static int sd_prepare_flush(request_queue_t *q, struct request *rq)
{
	struct scsi_device *sdev = q->queuedata;
	struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);

	if (sdkp->WCE) {
		memset(rq->cmd, 0, sizeof(rq->cmd));
		rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
		rq->timeout = SD_TIMEOUT;
		rq->cmd[0] = SYNCHRONIZE_CACHE;
		return 1;
	}

	return 0;
}

static void sd_rescan(struct device *dev)
{
	struct scsi_disk *sdkp = dev_get_drvdata(dev);
	sd_revalidate_disk(sdkp->disk);
}


#ifdef CONFIG_COMPAT
/* 
 * This gets directly called from VFS. When the ioctl 
 * is not recognized we go back to the other translation paths. 
 */
static long sd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
	struct gendisk *disk = bdev->bd_disk;
	struct scsi_device *sdev = scsi_disk(disk)->device;

	/*
	 * If we are in the middle of error recovery, don't let anyone
	 * else try and use this device.  Also, if error recovery fails, it
	 * may try and take the device offline, in which case all further
	 * access to the device is prohibited.
	 */
	if (!scsi_block_when_processing_errors(sdev))
		return -ENODEV;
	       
	if (sdev->host->hostt->compat_ioctl) {
		int ret;

		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);

		return ret;
	}

	/* 
	 * Let the static ioctl translation table take care of it.
	 */
	return -ENOIOCTLCMD; 
}
#endif

static struct block_device_operations sd_fops = {
	.owner			= THIS_MODULE,
	.open			= sd_open,
	.release		= sd_release,
	.ioctl			= sd_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl		= sd_compat_ioctl,
#endif
	.media_changed		= sd_media_changed,
	.revalidate_disk	= sd_revalidate_disk,
};

/**
 *	sd_rw_intr - bottom half handler: called when the lower level
 *	driver has completed (successfully or otherwise) a scsi command.
 *	@SCpnt: mid-level's per command structure.
 *
 *	Note: potentially run from within an ISR. Must not block.
 **/
static void sd_rw_intr(struct scsi_cmnd * SCpnt)
{
	int result = SCpnt->result;
	int this_count = SCpnt->bufflen;
	int good_bytes = (result == 0 ? this_count : 0);
	sector_t block_sectors = 1;
	u64 first_err_block;
	sector_t error_sector;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;
	int sense_deferred = 0;
	int info_valid;

	if (result) {
		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
		if (sense_valid)
			sense_deferred = scsi_sense_is_deferred(&sshdr);
	}

#ifdef CONFIG_SCSI_LOGGING
	SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: %s: res=0x%x\n", 
				SCpnt->request->rq_disk->disk_name, result));
	if (sense_valid) {
		SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: sb[respc,sk,asc,"
				"ascq]=%x,%x,%x,%x\n", sshdr.response_code,
				sshdr.sense_key, sshdr.asc, sshdr.ascq));
	}
#endif
	/*
	   Handle MEDIUM ERRORs that indicate partial success.  Since this is a
	   relatively rare error condition, no care is taken to avoid
	   unnecessary additional work such as memcpy's that could be avoided.
	 */

	/* 
	 * If SG_IO from block layer then set good_bytes to stop retries;
	 * else if errors, check them, and if necessary prepare for
	 * (partial) retries.
	 */
	if (blk_pc_request(SCpnt->request))
		good_bytes = this_count;
	else if (driver_byte(result) != 0 &&
		 sense_valid && !sense_deferred) {
		switch (sshdr.sense_key) {
		case MEDIUM_ERROR:
			if (!blk_fs_request(SCpnt->request))
				break;
			info_valid = scsi_get_sense_info_fld(
				SCpnt->sense_buffer, SCSI_SENSE_BUFFERSIZE,
				&first_err_block);
			/*
			 * May want to warn and skip if following cast results
			 * in actual truncation (if sector_t < 64 bits)
			 */
			error_sector = (sector_t)first_err_block;
			if (SCpnt->request->bio != NULL)
				block_sectors = bio_sectors(SCpnt->request->bio);
			switch (SCpnt->device->sector_size) {
			case 1024:
				error_sector <<= 1;
				if (block_sectors < 2)
					block_sectors = 2;
				break;
			case 2048:
				error_sector <<= 2;
				if (block_sectors < 4)
					block_sectors = 4;
				break;
			case 4096:
				error_sector <<=3;
				if (block_sectors < 8)
					block_sectors = 8;
				break;
			case 256:
				error_sector >>= 1;
				break;
			default:
				break;
			}

			error_sector &= ~(block_sectors - 1);
			good_bytes = (error_sector - SCpnt->request->sector) << 9;
			if (good_bytes < 0 || good_bytes >= this_count)
				good_bytes = 0;
			break;

		case RECOVERED_ERROR: /* an error occurred, but it recovered */
		case NO_SENSE: /* LLDD got sense data */
			/*
			 * Inform the user, but make sure that it's not treated
			 * as a hard error.
			 */
			scsi_print_sense("sd", SCpnt);
			SCpnt->result = 0;
			memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
			good_bytes = this_count;
			break;

		case ILLEGAL_REQUEST:
			if (SCpnt->device->use_10_for_rw &&
			    (SCpnt->cmnd[0] == READ_10 ||
			     SCpnt->cmnd[0] == WRITE_10))
				SCpnt->device->use_10_for_rw = 0;
			if (SCpnt->device->use_10_for_ms &&
			    (SCpnt->cmnd[0] == MODE_SENSE_10 ||
			     SCpnt->cmnd[0] == MODE_SELECT_10))
				SCpnt->device->use_10_for_ms = 0;
			break;

		default:
			break;
		}
	}
	/*
	 * This calls the generic completion function, now that we know
	 * how many actual sectors finished, and how many sectors we need
	 * to say have failed.
	 */
	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
}

952 953
static int media_not_present(struct scsi_disk *sdkp,
			     struct scsi_sense_hdr *sshdr)
L
Linus Torvalds 已提交
954 955
{

956
	if (!scsi_sense_valid(sshdr))
L
Linus Torvalds 已提交
957 958
		return 0;
	/* not invoked for commands that could return deferred errors */
959 960 961 962 963 964
	if (sshdr->sense_key != NOT_READY &&
	    sshdr->sense_key != UNIT_ATTENTION)
		return 0;
	if (sshdr->asc != 0x3A) /* medium not present */
		return 0;

L
Linus Torvalds 已提交
965 966 967 968 969 970 971 972
	set_media_not_present(sdkp);
	return 1;
}

/*
 * spinup disk - called only in sd_revalidate_disk()
 */
static void
973 974
sd_spinup_disk(struct scsi_disk *sdkp, char *diskname)
{
L
Linus Torvalds 已提交
975
	unsigned char cmd[10];
976
	unsigned long spintime_expire = 0;
L
Linus Torvalds 已提交
977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992
	int retries, spintime;
	unsigned int the_result;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;

	spintime = 0;

	/* Spin up drives, as required.  Only do this at boot time */
	/* Spinup needs to be done for module loads too. */
	do {
		retries = 0;

		do {
			cmd[0] = TEST_UNIT_READY;
			memset((void *) &cmd[1], 0, 9);

993 994 995 996
			the_result = scsi_execute_req(sdkp->device, cmd,
						      DMA_NONE, NULL, 0,
						      &sshdr, SD_TIMEOUT,
						      SD_MAX_RETRIES);
L
Linus Torvalds 已提交
997 998

			if (the_result)
999
				sense_valid = scsi_sense_valid(&sshdr);
L
Linus Torvalds 已提交
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010
			retries++;
		} while (retries < 3 && 
			 (!scsi_status_is_good(the_result) ||
			  ((driver_byte(the_result) & DRIVER_SENSE) &&
			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));

		/*
		 * If the drive has indicated to us that it doesn't have
		 * any media in it, don't bother with any of the rest of
		 * this crap.
		 */
1011
		if (media_not_present(sdkp, &sshdr))
L
Linus Torvalds 已提交
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049
			return;

		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
			/* no sense, TUR either succeeded or failed
			 * with a status error */
			if(!spintime && !scsi_status_is_good(the_result))
				printk(KERN_NOTICE "%s: Unit Not Ready, "
				       "error = 0x%x\n", diskname, the_result);
			break;
		}
					
		/*
		 * The device does not want the automatic start to be issued.
		 */
		if (sdkp->device->no_start_on_add) {
			break;
		}

		/*
		 * If manual intervention is required, or this is an
		 * absent USB storage device, a spinup is meaningless.
		 */
		if (sense_valid &&
		    sshdr.sense_key == NOT_READY &&
		    sshdr.asc == 4 && sshdr.ascq == 3) {
			break;		/* manual intervention required */

		/*
		 * Issue command to spin up drive when not ready
		 */
		} else if (sense_valid && sshdr.sense_key == NOT_READY) {
			if (!spintime) {
				printk(KERN_NOTICE "%s: Spinning up disk...",
				       diskname);
				cmd[0] = START_STOP;
				cmd[1] = 1;	/* Return immediately */
				memset((void *) &cmd[2], 0, 8);
				cmd[4] = 1;	/* Start spin cycle */
1050 1051 1052
				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
						 NULL, 0, &sshdr,
						 SD_TIMEOUT, SD_MAX_RETRIES);
1053 1054
				spintime_expire = jiffies + 100 * HZ;
				spintime = 1;
L
Linus Torvalds 已提交
1055 1056 1057 1058
			}
			/* Wait 1 second for next try */
			msleep(1000);
			printk(".");
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073

		/*
		 * Wait for USB flash devices with slow firmware.
		 * Yes, this sense key/ASC combination shouldn't
		 * occur here.  It's characteristic of these devices.
		 */
		} else if (sense_valid &&
				sshdr.sense_key == UNIT_ATTENTION &&
				sshdr.asc == 0x28) {
			if (!spintime) {
				spintime_expire = jiffies + 5 * HZ;
				spintime = 1;
			}
			/* Wait 1 second for next try */
			msleep(1000);
L
Linus Torvalds 已提交
1074 1075 1076 1077 1078 1079
		} else {
			/* we don't understand the sense code, so it's
			 * probably pointless to loop */
			if(!spintime) {
				printk(KERN_NOTICE "%s: Unit Not Ready, "
					"sense:\n", diskname);
1080
				scsi_print_sense_hdr("", &sshdr);
L
Linus Torvalds 已提交
1081 1082 1083 1084
			}
			break;
		}
				
1085
	} while (spintime && time_before_eq(jiffies, spintime_expire));
L
Linus Torvalds 已提交
1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099

	if (spintime) {
		if (scsi_status_is_good(the_result))
			printk("ready\n");
		else
			printk("not responding...\n");
	}
}

/*
 * read disk capacity
 */
static void
sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
1100 1101
		 unsigned char *buffer)
{
L
Linus Torvalds 已提交
1102 1103 1104 1105 1106 1107
	unsigned char cmd[16];
	int the_result, retries;
	int sector_size = 0;
	int longrc = 0;
	struct scsi_sense_hdr sshdr;
	int sense_valid = 0;
1108
	struct scsi_device *sdp = sdkp->device;
L
Linus Torvalds 已提交
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124

repeat:
	retries = 3;
	do {
		if (longrc) {
			memset((void *) cmd, 0, 16);
			cmd[0] = SERVICE_ACTION_IN;
			cmd[1] = SAI_READ_CAPACITY_16;
			cmd[13] = 12;
			memset((void *) buffer, 0, 12);
		} else {
			cmd[0] = READ_CAPACITY;
			memset((void *) &cmd[1], 0, 9);
			memset((void *) buffer, 0, 8);
		}
		
1125 1126 1127
		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
					      buffer, longrc ? 12 : 8, &sshdr,
					      SD_TIMEOUT, SD_MAX_RETRIES);
L
Linus Torvalds 已提交
1128

1129
		if (media_not_present(sdkp, &sshdr))
L
Linus Torvalds 已提交
1130 1131 1132
			return;

		if (the_result)
1133
			sense_valid = scsi_sense_valid(&sshdr);
L
Linus Torvalds 已提交
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147
		retries--;

	} while (the_result && retries);

	if (the_result && !longrc) {
		printk(KERN_NOTICE "%s : READ CAPACITY failed.\n"
		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
		       diskname, diskname,
		       status_byte(the_result),
		       msg_byte(the_result),
		       host_byte(the_result),
		       driver_byte(the_result));

		if (driver_byte(the_result) & DRIVER_SENSE)
1148
			scsi_print_sense_hdr("sd", &sshdr);
L
Linus Torvalds 已提交
1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
		else
			printk("%s : sense not available. \n", diskname);

		/* Set dirty bit for removable devices if not ready -
		 * sometimes drives will not report this properly. */
		if (sdp->removable &&
		    sense_valid && sshdr.sense_key == NOT_READY)
			sdp->changed = 1;

		/* Either no media are present but the drive didn't tell us,
		   or they are present but the read capacity command fails */
		/* sdkp->media_present = 0; -- not always correct */
		sdkp->capacity = 0x200000; /* 1 GB - random */

		return;
	} else if (the_result && longrc) {
		/* READ CAPACITY(16) has been failed */
		printk(KERN_NOTICE "%s : READ CAPACITY(16) failed.\n"
		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
		       diskname, diskname,
		       status_byte(the_result),
		       msg_byte(the_result),
		       host_byte(the_result),
		       driver_byte(the_result));
		printk(KERN_NOTICE "%s : use 0xffffffff as device size\n",
		       diskname);
		
		sdkp->capacity = 1 + (sector_t) 0xffffffff;		
		goto got_data;
	}	
	
	if (!longrc) {
		sector_size = (buffer[4] << 24) |
			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
		if (buffer[0] == 0xff && buffer[1] == 0xff &&
		    buffer[2] == 0xff && buffer[3] == 0xff) {
			if(sizeof(sdkp->capacity) > 4) {
				printk(KERN_NOTICE "%s : very big device. try to use"
				       " READ CAPACITY(16).\n", diskname);
				longrc = 1;
				goto repeat;
			}
			printk(KERN_ERR "%s: too big for this kernel.  Use a "
			       "kernel compiled with support for large block "
			       "devices.\n", diskname);
			sdkp->capacity = 0;
			goto got_data;
		}
		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
			(buffer[1] << 16) |
			(buffer[2] << 8) |
			buffer[3]);			
	} else {
		sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
			((u64)buffer[1] << 48) |
			((u64)buffer[2] << 40) |
			((u64)buffer[3] << 32) |
			((sector_t)buffer[4] << 24) |
			((sector_t)buffer[5] << 16) |
			((sector_t)buffer[6] << 8)  |
			(sector_t)buffer[7]);
			
		sector_size = (buffer[8] << 24) |
			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
	}	

	/* Some devices return the total number of sectors, not the
	 * highest sector number.  Make the necessary adjustment. */
	if (sdp->fix_capacity)
		--sdkp->capacity;

got_data:
	if (sector_size == 0) {
		sector_size = 512;
		printk(KERN_NOTICE "%s : sector size 0 reported, "
		       "assuming 512.\n", diskname);
	}

	if (sector_size != 512 &&
	    sector_size != 1024 &&
	    sector_size != 2048 &&
	    sector_size != 4096 &&
	    sector_size != 256) {
		printk(KERN_NOTICE "%s : unsupported sector size "
		       "%d.\n", diskname, sector_size);
		/*
		 * The user might want to re-format the drive with
		 * a supported sectorsize.  Once this happens, it
		 * would be relatively trivial to set the thing up.
		 * For this reason, we leave the thing in the table.
		 */
		sdkp->capacity = 0;
		/*
		 * set a bogus sector size so the normal read/write
		 * logic in the block layer will eventually refuse any
		 * request on this device without tripping over power
		 * of two sector size assumptions
		 */
		sector_size = 512;
	}
	{
		/*
		 * The msdos fs needs to know the hardware sector size
		 * So I have created this table. See ll_rw_blk.c
		 * Jacques Gelinas (Jacques@solucorp.qc.ca)
		 */
		int hard_sector = sector_size;
		sector_t sz = sdkp->capacity * (hard_sector/256);
		request_queue_t *queue = sdp->request_queue;
		sector_t mb;

		blk_queue_hardsect_size(queue, hard_sector);
		/* avoid 64-bit division on 32-bit platforms */
		mb = sz >> 1;
		sector_div(sz, 1250);
		mb -= sz - 974;
		sector_div(mb, 1950);

		printk(KERN_NOTICE "SCSI device %s: "
		       "%llu %d-byte hdwr sectors (%llu MB)\n",
		       diskname, (unsigned long long)sdkp->capacity,
		       hard_sector, (unsigned long long)mb);
	}

	/* Rescale capacity to 512-byte units */
	if (sector_size == 4096)
		sdkp->capacity <<= 3;
	else if (sector_size == 2048)
		sdkp->capacity <<= 2;
	else if (sector_size == 1024)
		sdkp->capacity <<= 1;
	else if (sector_size == 256)
		sdkp->capacity >>= 1;

	sdkp->device->sector_size = sector_size;
}

/* called with buffer of length 512 */
static inline int
1288 1289 1290
sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
		 unsigned char *buffer, int len, struct scsi_mode_data *data,
		 struct scsi_sense_hdr *sshdr)
L
Linus Torvalds 已提交
1291
{
1292
	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
1293
			       SD_TIMEOUT, SD_MAX_RETRIES, data,
1294
			       sshdr);
L
Linus Torvalds 已提交
1295 1296 1297 1298 1299 1300 1301 1302
}

/*
 * read write protect setting, if possible - called only in sd_revalidate_disk()
 * called with buffer of length 512
 */
static void
sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
1303 1304
			   unsigned char *buffer)
{
L
Linus Torvalds 已提交
1305
	int res;
1306
	struct scsi_device *sdp = sdkp->device;
L
Linus Torvalds 已提交
1307 1308 1309
	struct scsi_mode_data data;

	set_disk_ro(sdkp->disk, 0);
1310
	if (sdp->skip_ms_page_3f) {
L
Linus Torvalds 已提交
1311 1312 1313 1314
		printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
		return;
	}

1315 1316
	if (sdp->use_192_bytes_for_3f) {
		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
L
Linus Torvalds 已提交
1317 1318 1319 1320 1321 1322
	} else {
		/*
		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
		 * We have to start carefully: some devices hang if we ask
		 * for more than is available.
		 */
1323
		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);
L
Linus Torvalds 已提交
1324 1325 1326 1327 1328 1329 1330 1331

		/*
		 * Second attempt: ask for page 0 When only page 0 is
		 * implemented, a request for page 3F may return Sense Key
		 * 5: Illegal Request, Sense Code 24: Invalid field in
		 * CDB.
		 */
		if (!scsi_status_is_good(res))
1332
			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);
L
Linus Torvalds 已提交
1333 1334 1335 1336 1337

		/*
		 * Third attempt: ask 255 bytes, as we did earlier.
		 */
		if (!scsi_status_is_good(res))
1338 1339
			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
					       &data, NULL);
L
Linus Torvalds 已提交
1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360
	}

	if (!scsi_status_is_good(res)) {
		printk(KERN_WARNING
		       "%s: test WP failed, assume Write Enabled\n", diskname);
	} else {
		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
		set_disk_ro(sdkp->disk, sdkp->write_prot);
		printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname,
		       sdkp->write_prot ? "on" : "off");
		printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n",
		       diskname, buffer[0], buffer[1], buffer[2], buffer[3]);
	}
}

/*
 * sd_read_cache_type - called only from sd_revalidate_disk()
 * called with buffer of length 512
 */
static void
sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
1361
		   unsigned char *buffer)
1362
{
L
Linus Torvalds 已提交
1363
	int len = 0, res;
1364
	struct scsi_device *sdp = sdkp->device;
L
Linus Torvalds 已提交
1365

1366 1367
	int dbd;
	int modepage;
L
Linus Torvalds 已提交
1368 1369 1370
	struct scsi_mode_data data;
	struct scsi_sense_hdr sshdr;

1371
	if (sdp->skip_ms_page_8)
L
Linus Torvalds 已提交
1372 1373
		goto defaults;

1374
	if (sdp->type == TYPE_RBC) {
1375 1376 1377 1378 1379 1380 1381
		modepage = 6;
		dbd = 8;
	} else {
		modepage = 8;
		dbd = 0;
	}

L
Linus Torvalds 已提交
1382
	/* cautiously ask */
1383
	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
L
Linus Torvalds 已提交
1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403

	if (!scsi_status_is_good(res))
		goto bad_sense;

	/* that went OK, now ask for the proper length */
	len = data.length;

	/*
	 * We're only interested in the first three bytes, actually.
	 * But the data cache page is defined for the first 20.
	 */
	if (len < 3)
		goto bad_sense;
	if (len > 20)
		len = 20;

	/* Take headers and block descriptors into account */
	len += data.header_length + data.block_descriptor_length;

	/* Get the data */
1404
	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
L
Linus Torvalds 已提交
1405 1406 1407 1408 1409 1410 1411

	if (scsi_status_is_good(res)) {
		const char *types[] = {
			"write through", "none", "write back",
			"write back, no read (daft)"
		};
		int ct = 0;
1412
		int offset = data.header_length + data.block_descriptor_length;
L
Linus Torvalds 已提交
1413

1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
		if ((buffer[offset] & 0x3f) != modepage) {
			printk(KERN_ERR "%s: got wrong page\n", diskname);
			goto defaults;
		}

		if (modepage == 8) {
			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
		} else {
			sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
			sdkp->RCD = 0;
		}
L
Linus Torvalds 已提交
1426 1427 1428 1429 1430 1431 1432 1433 1434 1435

		ct =  sdkp->RCD + 2*sdkp->WCE;

		printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
		       diskname, types[ct]);

		return;
	}

bad_sense:
1436
	if (scsi_sense_valid(&sshdr) &&
L
Linus Torvalds 已提交
1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475
	    sshdr.sense_key == ILLEGAL_REQUEST &&
	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
		printk(KERN_NOTICE "%s: cache data unavailable\n",
		       diskname);	/* Invalid field in CDB */
	else
		printk(KERN_ERR "%s: asking for cache data failed\n",
		       diskname);

defaults:
	printk(KERN_ERR "%s: assuming drive cache: write through\n",
	       diskname);
	sdkp->WCE = 0;
	sdkp->RCD = 0;
}

/**
 *	sd_revalidate_disk - called the first time a new disk is seen,
 *	performs disk spin up, read_capacity, etc.
 *	@disk: struct gendisk we care about
 **/
static int sd_revalidate_disk(struct gendisk *disk)
{
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdp = sdkp->device;
	unsigned char *buffer;

	SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));

	/*
	 * If the device is offline, don't try and read capacity or any
	 * of the other niceties.
	 */
	if (!scsi_device_online(sdp))
		goto out;

	buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA);
	if (!buffer) {
		printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
		       "failure.\n");
1476
		goto out;
L
Linus Torvalds 已提交
1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
	}

	/* defaults, until the device tells us otherwise */
	sdp->sector_size = 512;
	sdkp->capacity = 0;
	sdkp->media_present = 1;
	sdkp->write_prot = 0;
	sdkp->WCE = 0;
	sdkp->RCD = 0;

1487
	sd_spinup_disk(sdkp, disk->disk_name);
L
Linus Torvalds 已提交
1488 1489 1490 1491 1492 1493

	/*
	 * Without media there is no reason to ask; moreover, some devices
	 * react badly if we do.
	 */
	if (sdkp->media_present) {
1494
		sd_read_capacity(sdkp, disk->disk_name, buffer);
L
Linus Torvalds 已提交
1495 1496
		if (sdp->removable)
			sd_read_write_protect_flag(sdkp, disk->disk_name,
1497 1498
						   buffer);
		sd_read_cache_type(sdkp, disk->disk_name, buffer);
L
Linus Torvalds 已提交
1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534
	}
		
	set_capacity(disk, sdkp->capacity);
	kfree(buffer);

 out:
	return 0;
}

/**
 *	sd_probe - called during driver initialization and whenever a
 *	new scsi device is attached to the system. It is called once
 *	for each scsi device (not just disks) present.
 *	@dev: pointer to device object
 *
 *	Returns 0 if successful (or not interested in this scsi device 
 *	(e.g. scanner)); 1 when there is an error.
 *
 *	Note: this function is invoked from the scsi mid-level.
 *	This function sets up the mapping between a given 
 *	<host,channel,id,lun> (found in sdp) and new device name 
 *	(e.g. /dev/sda). More precisely it is the block device major 
 *	and minor number that is chosen here.
 *
 *	Assume sd_attach is not re-entrant (for time being)
 *	Also think about sd_attach() and sd_remove() running coincidentally.
 **/
static int sd_probe(struct device *dev)
{
	struct scsi_device *sdp = to_scsi_device(dev);
	struct scsi_disk *sdkp;
	struct gendisk *gd;
	u32 index;
	int error;

	error = -ENODEV;
1535
	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
L
Linus Torvalds 已提交
1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571
		goto out;

	SCSI_LOG_HLQUEUE(3, printk("sd_attach: scsi device: <%d,%d,%d,%d>\n", 
			 sdp->host->host_no, sdp->channel, sdp->id, sdp->lun));

	error = -ENOMEM;
	sdkp = kmalloc(sizeof(*sdkp), GFP_KERNEL);
	if (!sdkp)
		goto out;

	memset (sdkp, 0, sizeof(*sdkp));
	kref_init(&sdkp->kref);

	gd = alloc_disk(16);
	if (!gd)
		goto out_free;

	if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))
		goto out_put;

	spin_lock(&sd_index_lock);
	error = idr_get_new(&sd_index_idr, NULL, &index);
	spin_unlock(&sd_index_lock);

	if (index >= SD_MAX_DISKS)
		error = -EBUSY;
	if (error)
		goto out_put;

	sdkp->device = sdp;
	sdkp->driver = &sd_template;
	sdkp->disk = gd;
	sdkp->index = index;
	sdkp->openers = 0;

	if (!sdp->timeout) {
1572
		if (sdp->type != TYPE_MOD)
L
Linus Torvalds 已提交
1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739
			sdp->timeout = SD_TIMEOUT;
		else
			sdp->timeout = SD_MOD_TIMEOUT;
	}

	gd->major = sd_major((index & 0xf0) >> 4);
	gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
	gd->minors = 16;
	gd->fops = &sd_fops;

	if (index < 26) {
		sprintf(gd->disk_name, "sd%c", 'a' + index % 26);
	} else if (index < (26 + 1) * 26) {
		sprintf(gd->disk_name, "sd%c%c",
			'a' + index / 26 - 1,'a' + index % 26);
	} else {
		const unsigned int m1 = (index / 26 - 1) / 26 - 1;
		const unsigned int m2 = (index / 26 - 1) % 26;
		const unsigned int m3 =  index % 26;
		sprintf(gd->disk_name, "sd%c%c%c",
			'a' + m1, 'a' + m2, 'a' + m3);
	}

	strcpy(gd->devfs_name, sdp->devfs_name);

	gd->private_data = &sdkp->driver;

	sd_revalidate_disk(gd);

	gd->driverfs_dev = &sdp->sdev_gendev;
	gd->flags = GENHD_FL_DRIVERFS;
	if (sdp->removable)
		gd->flags |= GENHD_FL_REMOVABLE;
	gd->queue = sdkp->device->request_queue;

	dev_set_drvdata(dev, sdkp);
	add_disk(gd);

	printk(KERN_NOTICE "Attached scsi %sdisk %s at scsi%d, channel %d, "
	       "id %d, lun %d\n", sdp->removable ? "removable " : "",
	       gd->disk_name, sdp->host->host_no, sdp->channel,
	       sdp->id, sdp->lun);

	return 0;

out_put:
	put_disk(gd);
out_free:
	kfree(sdkp);
out:
	return error;
}

/**
 *	sd_remove - called whenever a scsi disk (previously recognized by
 *	sd_probe) is detached from the system. It is called (potentially
 *	multiple times) during sd module unload.
 *	@sdp: pointer to mid level scsi device object
 *
 *	Note: this function is invoked from the scsi mid-level.
 *	This function potentially frees up a device name (e.g. /dev/sdc)
 *	that could be re-used by a subsequent sd_probe().
 *	This function is not called when the built-in sd driver is "exit-ed".
 **/
static int sd_remove(struct device *dev)
{
	struct scsi_disk *sdkp = dev_get_drvdata(dev);

	del_gendisk(sdkp->disk);
	sd_shutdown(dev);
	down(&sd_ref_sem);
	kref_put(&sdkp->kref, scsi_disk_release);
	up(&sd_ref_sem);

	return 0;
}

/**
 *	scsi_disk_release - Called to free the scsi_disk structure
 *	@kref: pointer to embedded kref
 *
 *	sd_ref_sem must be held entering this routine.  Because it is
 *	called on last put, you should always use the scsi_disk_get()
 *	scsi_disk_put() helpers which manipulate the semaphore directly
 *	and never do a direct kref_put().
 **/
static void scsi_disk_release(struct kref *kref)
{
	struct scsi_disk *sdkp = to_scsi_disk(kref);
	struct gendisk *disk = sdkp->disk;
	
	spin_lock(&sd_index_lock);
	idr_remove(&sd_index_idr, sdkp->index);
	spin_unlock(&sd_index_lock);

	disk->private_data = NULL;

	put_disk(disk);

	kfree(sdkp);
}

/*
 * Send a SYNCHRONIZE CACHE instruction down to the device through
 * the normal SCSI command structure.  Wait for the command to
 * complete.
 */
static void sd_shutdown(struct device *dev)
{
	struct scsi_device *sdp = to_scsi_device(dev);
	struct scsi_disk *sdkp = dev_get_drvdata(dev);

	if (!sdkp)
		return;         /* this can happen */

	if (!sdkp->WCE)
		return;

	printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
			sdkp->disk->disk_name);
	sd_sync_cache(sdp);
}	

/**
 *	init_sd - entry point for this driver (both when built in or when
 *	a module).
 *
 *	Note: this function registers this driver with the scsi mid-level.
 **/
static int __init init_sd(void)
{
	int majors = 0, i;

	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));

	for (i = 0; i < SD_MAJORS; i++)
		if (register_blkdev(sd_major(i), "sd") == 0)
			majors++;

	if (!majors)
		return -ENODEV;

	return scsi_register_driver(&sd_template.gendrv);
}

/**
 *	exit_sd - exit point for this driver (when it is a module).
 *
 *	Note: this function unregisters this driver from the scsi mid-level.
 **/
static void __exit exit_sd(void)
{
	int i;

	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));

	scsi_unregister_driver(&sd_template.gendrv);
	for (i = 0; i < SD_MAJORS; i++)
		unregister_blkdev(sd_major(i), "sd");
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eric Youngdale");
MODULE_DESCRIPTION("SCSI disk (sd) driver");

module_init(init_sd);
module_exit(exit_sd);