/*
   *      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/module.h>
  #include <linux/fs.h>
  #include <linux/kernel.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/delay.h>

  #include <linux/mutex.h>

  #include <linux/string_helpers.h>

  #include <linux/async.h>

  #include <linux/slab.h>

  #include <linux/pm_runtime.h>

  #include <asm/uaccess.h>

  #include <asm/unaligned.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 "sd.h"

  #include "scsi_logging.h"

  MODULE_AUTHOR("Eric Youngdale");
  MODULE_DESCRIPTION("SCSI disk (sd) driver");
  MODULE_LICENSE("GPL");
  
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK0_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK1_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK2_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK3_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK4_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK5_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK6_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK7_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK8_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK9_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK10_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK11_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK12_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK13_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK14_MAJOR);
  MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK15_MAJOR);

  MODULE_ALIAS_SCSI_DEVICE(TYPE_DISK);
  MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
  MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);

  #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)

  #define SD_MINORS	16

  #else

  #define SD_MINORS	0

  #endif

  static void sd_config_discard(struct scsi_disk *, unsigned int);

  static int  sd_revalidate_disk(struct gendisk *);

  static void sd_unlock_native_capacity(struct gendisk *disk);

  static int  sd_probe(struct device *);
  static int  sd_remove(struct device *);
  static void sd_shutdown(struct device *);
  static int sd_suspend(struct device *, pm_message_t state);
  static int sd_resume(struct device *);
  static void sd_rescan(struct device *);
  static int sd_done(struct scsi_cmnd *);
  static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);

  static void scsi_disk_release(struct device *cdev);

  static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
  static void sd_print_result(struct scsi_disk *, int);

  static DEFINE_SPINLOCK(sd_index_lock);

  static DEFINE_IDA(sd_index_ida);

  
  /* 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 DEFINE_MUTEX(sd_ref_mutex);

  static struct kmem_cache *sd_cdb_cache;
  static mempool_t *sd_cdb_pool;

  static const char *sd_cache_types[] = {
  	"write through", "none", "write back",
  	"write back, no read (daft)"
  };

  static ssize_t
  sd_store_cache_type(struct device *dev, struct device_attribute *attr,
  		    const char *buf, size_t count)

  {
  	int i, ct = -1, rcd, wce, sp;

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	struct scsi_device *sdp = sdkp->device;
  	char buffer[64];
  	char *buffer_data;
  	struct scsi_mode_data data;
  	struct scsi_sense_hdr sshdr;
  	int len;
  
  	if (sdp->type != TYPE_DISK)
  		/* no cache control on RBC devices; theoretically they
  		 * can do it, but there's probably so many exceptions
  		 * it's not worth the risk */
  		return -EINVAL;

  	for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {

  		len = strlen(sd_cache_types[i]);

  		if (strncmp(sd_cache_types[i], buf, len) == 0 &&
  		    buf[len] == '
  ') {
  			ct = i;
  			break;
  		}
  	}
  	if (ct < 0)
  		return -EINVAL;
  	rcd = ct & 0x01 ? 1 : 0;
  	wce = ct & 0x02 ? 1 : 0;
  	if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
  			    SD_MAX_RETRIES, &data, NULL))
  		return -EINVAL;

  	len = min_t(size_t, sizeof(buffer), data.length - data.header_length -

  		  data.block_descriptor_length);
  	buffer_data = buffer + data.header_length +
  		data.block_descriptor_length;
  	buffer_data[2] &= ~0x05;
  	buffer_data[2] |= wce << 2 | rcd;
  	sp = buffer_data[0] & 0x80 ? 1 : 0;
  
  	if (scsi_mode_select(sdp, 1, sp, 8, buffer_data, len, SD_TIMEOUT,
  			     SD_MAX_RETRIES, &data, &sshdr)) {
  		if (scsi_sense_valid(&sshdr))

  			sd_print_sense_hdr(sdkp, &sshdr);

  		return -EINVAL;
  	}

  	revalidate_disk(sdkp->disk);

  	return count;
  }

  static ssize_t
  sd_store_manage_start_stop(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	struct scsi_device *sdp = sdkp->device;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	sdp->manage_start_stop = simple_strtoul(buf, NULL, 10);
  
  	return count;
  }

  static ssize_t
  sd_store_allow_restart(struct device *dev, struct device_attribute *attr,
  		       const char *buf, size_t count)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	struct scsi_device *sdp = sdkp->device;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	if (sdp->type != TYPE_DISK)
  		return -EINVAL;
  
  	sdp->allow_restart = simple_strtoul(buf, NULL, 10);
  
  	return count;
  }

  static ssize_t
  sd_show_cache_type(struct device *dev, struct device_attribute *attr,
  		   char *buf)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	int ct = sdkp->RCD + 2*sdkp->WCE;
  
  	return snprintf(buf, 40, "%s
  ", sd_cache_types[ct]);
  }

  static ssize_t
  sd_show_fua(struct device *dev, struct device_attribute *attr, char *buf)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  
  	return snprintf(buf, 20, "%u
  ", sdkp->DPOFUA);
  }

  static ssize_t
  sd_show_manage_start_stop(struct device *dev, struct device_attribute *attr,
  			  char *buf)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	struct scsi_device *sdp = sdkp->device;
  
  	return snprintf(buf, 20, "%u
  ", sdp->manage_start_stop);
  }

  static ssize_t
  sd_show_allow_restart(struct device *dev, struct device_attribute *attr,
  		      char *buf)

  {

  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  
  	return snprintf(buf, 40, "%d
  ", sdkp->device->allow_restart);
  }

  static ssize_t
  sd_show_protection_type(struct device *dev, struct device_attribute *attr,
  			char *buf)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  
  	return snprintf(buf, 20, "%u
  ", sdkp->protection_type);
  }
  
  static ssize_t

  sd_show_protection_mode(struct device *dev, struct device_attribute *attr,
  			char *buf)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  	struct scsi_device *sdp = sdkp->device;
  	unsigned int dif, dix;
  
  	dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
  	dix = scsi_host_dix_capable(sdp->host, sdkp->protection_type);
  
  	if (!dix && scsi_host_dix_capable(sdp->host, SD_DIF_TYPE0_PROTECTION)) {
  		dif = 0;
  		dix = 1;
  	}
  
  	if (!dif && !dix)
  		return snprintf(buf, 20, "none
  ");
  
  	return snprintf(buf, 20, "%s%u
  ", dix ? "dix" : "dif", dif);
  }
  
  static ssize_t

  sd_show_app_tag_own(struct device *dev, struct device_attribute *attr,
  		    char *buf)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  
  	return snprintf(buf, 20, "%u
  ", sdkp->ATO);
  }

  static ssize_t
  sd_show_thin_provisioning(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);

  	return snprintf(buf, 20, "%u
  ", sdkp->lbpme);
  }
  
  static const char *lbp_mode[] = {
  	[SD_LBP_FULL]		= "full",
  	[SD_LBP_UNMAP]		= "unmap",
  	[SD_LBP_WS16]		= "writesame_16",
  	[SD_LBP_WS10]		= "writesame_10",
  	[SD_LBP_ZERO]		= "writesame_zero",
  	[SD_LBP_DISABLE]	= "disabled",
  };
  
  static ssize_t
  sd_show_provisioning_mode(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  
  	return snprintf(buf, 20, "%s
  ", lbp_mode[sdkp->provisioning_mode]);
  }
  
  static ssize_t
  sd_store_provisioning_mode(struct device *dev, struct device_attribute *attr,
  			   const char *buf, size_t count)
  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  	struct scsi_device *sdp = sdkp->device;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	if (sdp->type != TYPE_DISK)
  		return -EINVAL;
  
  	if (!strncmp(buf, lbp_mode[SD_LBP_UNMAP], 20))
  		sd_config_discard(sdkp, SD_LBP_UNMAP);
  	else if (!strncmp(buf, lbp_mode[SD_LBP_WS16], 20))
  		sd_config_discard(sdkp, SD_LBP_WS16);
  	else if (!strncmp(buf, lbp_mode[SD_LBP_WS10], 20))
  		sd_config_discard(sdkp, SD_LBP_WS10);
  	else if (!strncmp(buf, lbp_mode[SD_LBP_ZERO], 20))
  		sd_config_discard(sdkp, SD_LBP_ZERO);
  	else if (!strncmp(buf, lbp_mode[SD_LBP_DISABLE], 20))
  		sd_config_discard(sdkp, SD_LBP_DISABLE);
  	else
  		return -EINVAL;
  
  	return count;

  }

  static struct device_attribute sd_disk_attrs[] = {

  	__ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
  	       sd_store_cache_type),
  	__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),

  	__ATTR(allow_restart, S_IRUGO|S_IWUSR, sd_show_allow_restart,
  	       sd_store_allow_restart),

  	__ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
  	       sd_store_manage_start_stop),

  	__ATTR(protection_type, S_IRUGO, sd_show_protection_type, NULL),

  	__ATTR(protection_mode, S_IRUGO, sd_show_protection_mode, NULL),

  	__ATTR(app_tag_own, S_IRUGO, sd_show_app_tag_own, NULL),

  	__ATTR(thin_provisioning, S_IRUGO, sd_show_thin_provisioning, NULL),

  	__ATTR(provisioning_mode, S_IRUGO|S_IWUSR, sd_show_provisioning_mode,
  	       sd_store_provisioning_mode),

  	__ATTR_NULL,
  };
  
  static struct class sd_disk_class = {
  	.name		= "scsi_disk",
  	.owner		= THIS_MODULE,

  	.dev_release	= scsi_disk_release,
  	.dev_attrs	= sd_disk_attrs,

  };

  
  static struct scsi_driver sd_template = {
  	.owner			= THIS_MODULE,
  	.gendrv = {
  		.name		= "sd",
  		.probe		= sd_probe,
  		.remove		= sd_remove,

  		.suspend	= sd_suspend,
  		.resume		= sd_resume,

  		.shutdown	= sd_shutdown,
  	},
  	.rescan			= sd_rescan,

  	.done			= sd_done,

  };
  
  /*
   * 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 */
  	}
  }

  static struct scsi_disk *__scsi_disk_get(struct gendisk *disk)

  {
  	struct scsi_disk *sdkp = NULL;

  	if (disk->private_data) {
  		sdkp = scsi_disk(disk);
  		if (scsi_device_get(sdkp->device) == 0)

  			get_device(&sdkp->dev);

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

  	mutex_lock(&sd_ref_mutex);

  	sdkp = __scsi_disk_get(disk);

  	mutex_unlock(&sd_ref_mutex);

  	return sdkp;

  }

  static struct scsi_disk *scsi_disk_get_from_dev(struct device *dev)
  {
  	struct scsi_disk *sdkp;

  	mutex_lock(&sd_ref_mutex);

  	sdkp = dev_get_drvdata(dev);
  	if (sdkp)
  		sdkp = __scsi_disk_get(sdkp->disk);

  	mutex_unlock(&sd_ref_mutex);

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

  	mutex_lock(&sd_ref_mutex);

  	put_device(&sdkp->dev);

  	scsi_device_put(sdev);

  	mutex_unlock(&sd_ref_mutex);

  }

  static void sd_prot_op(struct scsi_cmnd *scmd, unsigned int dif)
  {
  	unsigned int prot_op = SCSI_PROT_NORMAL;
  	unsigned int dix = scsi_prot_sg_count(scmd);
  
  	if (scmd->sc_data_direction == DMA_FROM_DEVICE) {
  		if (dif && dix)
  			prot_op = SCSI_PROT_READ_PASS;
  		else if (dif && !dix)
  			prot_op = SCSI_PROT_READ_STRIP;
  		else if (!dif && dix)
  			prot_op = SCSI_PROT_READ_INSERT;
  	} else {
  		if (dif && dix)
  			prot_op = SCSI_PROT_WRITE_PASS;
  		else if (dif && !dix)
  			prot_op = SCSI_PROT_WRITE_INSERT;
  		else if (!dif && dix)
  			prot_op = SCSI_PROT_WRITE_STRIP;
  	}
  
  	scsi_set_prot_op(scmd, prot_op);
  	scsi_set_prot_type(scmd, dif);
  }

  static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode)
  {
  	struct request_queue *q = sdkp->disk->queue;
  	unsigned int logical_block_size = sdkp->device->sector_size;
  	unsigned int max_blocks = 0;
  
  	q->limits.discard_zeroes_data = sdkp->lbprz;

  	q->limits.discard_alignment = sdkp->unmap_alignment *
  		logical_block_size;

  	q->limits.discard_granularity =
  		max(sdkp->physical_block_size,
  		    sdkp->unmap_granularity * logical_block_size);
  
  	switch (mode) {
  
  	case SD_LBP_DISABLE:
  		q->limits.max_discard_sectors = 0;
  		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
  		return;
  
  	case SD_LBP_UNMAP:
  		max_blocks = min_not_zero(sdkp->max_unmap_blocks, 0xffffffff);
  		break;
  
  	case SD_LBP_WS16:
  		max_blocks = min_not_zero(sdkp->max_ws_blocks, 0xffffffff);
  		break;
  
  	case SD_LBP_WS10:
  		max_blocks = min_not_zero(sdkp->max_ws_blocks, (u32)0xffff);
  		break;
  
  	case SD_LBP_ZERO:
  		max_blocks = min_not_zero(sdkp->max_ws_blocks, (u32)0xffff);
  		q->limits.discard_zeroes_data = 1;
  		break;
  	}
  
  	q->limits.max_discard_sectors = max_blocks * (logical_block_size >> 9);
  	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
  
  	sdkp->provisioning_mode = mode;
  }

  /**

   * scsi_setup_discard_cmnd - unmap blocks on thinly provisioned device
   * @sdp: scsi device to operate one

   * @rq: Request to prepare
   *
   * Will issue either UNMAP or WRITE SAME(16) depending on preference
   * indicated by target device.
   **/

  static int scsi_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq)

  {
  	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
  	struct bio *bio = rq->bio;
  	sector_t sector = bio->bi_sector;

  	unsigned int nr_sectors = bio_sectors(bio);
  	unsigned int len;

  	int ret;

  	char *buf;

  	struct page *page;

  
  	if (sdkp->device->sector_size == 4096) {
  		sector >>= 3;

  		nr_sectors >>= 3;

  	}

  	rq->timeout = SD_TIMEOUT;
  
  	memset(rq->cmd, 0, rq->cmd_len);

  	page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
  	if (!page)
  		return BLKPREP_DEFER;

  	switch (sdkp->provisioning_mode) {
  	case SD_LBP_UNMAP:
  		buf = page_address(page);

  		rq->cmd_len = 10;

  		rq->cmd[0] = UNMAP;
  		rq->cmd[8] = 24;

  
  		put_unaligned_be16(6 + 16, &buf[0]);
  		put_unaligned_be16(16, &buf[2]);
  		put_unaligned_be64(sector, &buf[8]);

  		put_unaligned_be32(nr_sectors, &buf[16]);

  		len = 24;

  		break;
  
  	case SD_LBP_WS16:

  		rq->cmd_len = 16;

  		rq->cmd[0] = WRITE_SAME_16;
  		rq->cmd[1] = 0x8; /* UNMAP */
  		put_unaligned_be64(sector, &rq->cmd[2]);

  		put_unaligned_be32(nr_sectors, &rq->cmd[10]);
  
  		len = sdkp->device->sector_size;

  		break;
  
  	case SD_LBP_WS10:
  	case SD_LBP_ZERO:
  		rq->cmd_len = 10;
  		rq->cmd[0] = WRITE_SAME;
  		if (sdkp->provisioning_mode == SD_LBP_WS10)
  			rq->cmd[1] = 0x8; /* UNMAP */
  		put_unaligned_be32(sector, &rq->cmd[2]);
  		put_unaligned_be16(nr_sectors, &rq->cmd[7]);
  
  		len = sdkp->device->sector_size;
  		break;
  
  	default:

  		ret = BLKPREP_KILL;

  		goto out;

  	}

  	blk_add_request_payload(rq, page, len);

  	ret = scsi_setup_blk_pc_cmnd(sdp, rq);
  	rq->buffer = page_address(page);

  
  out:

  	if (ret != BLKPREP_OK) {
  		__free_page(page);
  		rq->buffer = NULL;
  	}

  	return ret;
  }

  static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
  {

  	rq->timeout = SD_FLUSH_TIMEOUT;

  	rq->retries = SD_MAX_RETRIES;
  	rq->cmd[0] = SYNCHRONIZE_CACHE;
  	rq->cmd_len = 10;
  
  	return scsi_setup_blk_pc_cmnd(sdp, rq);
  }

  static void sd_unprep_fn(struct request_queue *q, struct request *rq)
  {

  	if (rq->cmd_flags & REQ_DISCARD) {
  		free_page((unsigned long)rq->buffer);
  		rq->buffer = NULL;
  	}

  }
  
  /**

   *	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_prep_fn(struct request_queue *q, struct request *rq)

  {

  	struct scsi_cmnd *SCpnt;
  	struct scsi_device *sdp = q->queuedata;

  	struct gendisk *disk = rq->rq_disk;

  	struct scsi_disk *sdkp;

  	sector_t block = blk_rq_pos(rq);

  	sector_t threshold;

  	unsigned int this_count = blk_rq_sectors(rq);

  	int ret, host_dif;

  	unsigned char protect;

  	/*
  	 * Discard request come in as REQ_TYPE_FS but we turn them into
  	 * block PC requests to make life easier.
  	 */

  	if (rq->cmd_flags & REQ_DISCARD) {
  		ret = scsi_setup_discard_cmnd(sdp, rq);
  		goto out;

  	} else if (rq->cmd_flags & REQ_FLUSH) {
  		ret = scsi_setup_flush_cmnd(sdp, rq);
  		goto out;

  	} else if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {

  		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
  		goto out;
  	} else if (rq->cmd_type != REQ_TYPE_FS) {
  		ret = BLKPREP_KILL;
  		goto out;
  	}
  	ret = scsi_setup_fs_cmnd(sdp, rq);
  	if (ret != BLKPREP_OK)
  		goto out;
  	SCpnt = rq->special;

  	sdkp = scsi_disk(disk);

  
  	/* from here on until we're complete, any goto out
  	 * is used for a killable error condition */
  	ret = BLKPREP_KILL;

  	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
  					"sd_init_command: block=%llu, "
  					"count=%d
  ",
  					(unsigned long long)block,
  					this_count));

  
  	if (!sdp || !scsi_device_online(sdp) ||

  	    block + blk_rq_sectors(rq) > get_capacity(disk)) {

  		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,

  						"Finishing %u sectors
  ",
  						blk_rq_sectors(rq)));

  		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
  						"Retry with 0x%p
  ", SCpnt));

  		goto out;

  	}
  
  	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 or is not present. Prohibiting further I/O.
  "); */

  		goto out;

  	}

  	/*

  	 * Some SD card readers can't handle multi-sector accesses which touch
  	 * the last one or two hardware sectors.  Split accesses as needed.

  	 */

  	threshold = get_capacity(disk) - SD_LAST_BUGGY_SECTORS *
  		(sdp->sector_size / 512);
  
  	if (unlikely(sdp->last_sector_bug && block + this_count > threshold)) {
  		if (block < threshold) {
  			/* Access up to the threshold but not beyond */
  			this_count = threshold - block;
  		} else {
  			/* Access only a single hardware sector */
  			this_count = sdp->sector_size / 512;
  		}
  	}

  	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu
  ",
  					(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) || (blk_rq_sectors(rq) & 1)) {

  			scmd_printk(KERN_ERR, SCpnt,
  				    "Bad block number requested
  ");

  			goto out;

  		} else {
  			block = block >> 1;
  			this_count = this_count >> 1;
  		}
  	}
  	if (sdp->sector_size == 2048) {

  		if ((block & 3) || (blk_rq_sectors(rq) & 3)) {

  			scmd_printk(KERN_ERR, SCpnt,
  				    "Bad block number requested
  ");

  			goto out;

  		} else {
  			block = block >> 2;
  			this_count = this_count >> 2;
  		}
  	}
  	if (sdp->sector_size == 4096) {

  		if ((block & 7) || (blk_rq_sectors(rq) & 7)) {

  			scmd_printk(KERN_ERR, SCpnt,
  				    "Bad block number requested
  ");

  			goto out;

  		} else {
  			block = block >> 3;
  			this_count = this_count >> 3;
  		}
  	}
  	if (rq_data_dir(rq) == WRITE) {
  		if (!sdp->writeable) {

  			goto out;

  		}
  		SCpnt->cmnd[0] = WRITE_6;
  		SCpnt->sc_data_direction = DMA_TO_DEVICE;

  
  		if (blk_integrity_rq(rq) &&
  		    sd_dif_prepare(rq, block, sdp->sector_size) == -EIO)
  			goto out;

  	} else if (rq_data_dir(rq) == READ) {
  		SCpnt->cmnd[0] = READ_6;
  		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
  	} else {

  		scmd_printk(KERN_ERR, SCpnt, "Unknown command %x
  ", rq->cmd_flags);

  		goto out;

  	}

  	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,

  					"%s %d/%u 512 byte blocks.
  ",

  					(rq_data_dir(rq) == WRITE) ?
  					"writing" : "reading", this_count,

  					blk_rq_sectors(rq)));

  	/* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */

  	host_dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
  	if (host_dif)

  		protect = 1 << 5;

  	else

  		protect = 0;
  
  	if (host_dif == SD_DIF_TYPE2_PROTECTION) {
  		SCpnt->cmnd = mempool_alloc(sd_cdb_pool, GFP_ATOMIC);
  
  		if (unlikely(SCpnt->cmnd == NULL)) {
  			ret = BLKPREP_DEFER;
  			goto out;
  		}

  		SCpnt->cmd_len = SD_EXT_CDB_SIZE;
  		memset(SCpnt->cmnd, 0, SCpnt->cmd_len);
  		SCpnt->cmnd[0] = VARIABLE_LENGTH_CMD;
  		SCpnt->cmnd[7] = 0x18;
  		SCpnt->cmnd[9] = (rq_data_dir(rq) == READ) ? READ_32 : WRITE_32;

  		SCpnt->cmnd[10] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);

  
  		/* LBA */
  		SCpnt->cmnd[12] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
  		SCpnt->cmnd[13] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
  		SCpnt->cmnd[14] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
  		SCpnt->cmnd[15] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
  		SCpnt->cmnd[16] = (unsigned char) (block >> 24) & 0xff;
  		SCpnt->cmnd[17] = (unsigned char) (block >> 16) & 0xff;
  		SCpnt->cmnd[18] = (unsigned char) (block >> 8) & 0xff;
  		SCpnt->cmnd[19] = (unsigned char) block & 0xff;
  
  		/* Expected Indirect LBA */
  		SCpnt->cmnd[20] = (unsigned char) (block >> 24) & 0xff;
  		SCpnt->cmnd[21] = (unsigned char) (block >> 16) & 0xff;
  		SCpnt->cmnd[22] = (unsigned char) (block >> 8) & 0xff;
  		SCpnt->cmnd[23] = (unsigned char) block & 0xff;
  
  		/* Transfer length */
  		SCpnt->cmnd[28] = (unsigned char) (this_count >> 24) & 0xff;
  		SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
  		SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
  		SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
  	} else if (block > 0xffffffff) {

  		SCpnt->cmnd[0] += READ_16 - READ_6;

  		SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);

  		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) ||

  		   scsi_device_protection(SCpnt->device) ||

  		   SCpnt->device->use_10_for_rw) {
  		if (this_count > 0xffff)
  			this_count = 0xffff;
  
  		SCpnt->cmnd[0] += READ_10 - READ_6;

  		SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);

  		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 {

  		if (unlikely(rq->cmd_flags & REQ_FUA)) {

  			/*
  			 * This happens only if this drive failed
  			 * 10byte rw command with ILLEGAL_REQUEST
  			 * during operation and thus turned off
  			 * use_10_for_rw.
  			 */

  			scmd_printk(KERN_ERR, SCpnt,
  				    "FUA write on READ/WRITE(6) drive
  ");

  			goto out;

  		}

  		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->sdb.length = this_count * sdp->sector_size;

  	/* If DIF or DIX is enabled, tell HBA how to handle request */

  	if (host_dif || scsi_prot_sg_count(SCpnt))

  		sd_prot_op(SCpnt, host_dif);

  	/*
  	 * 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;

  
  	/*

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

  	ret = BLKPREP_OK;
   out:
  	return scsi_prep_return(q, rq, ret);

  }
  
  /**
   *	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.

   *
   *	Locking: called with bdev->bd_mutex held.

   **/

  static int sd_open(struct block_device *bdev, fmode_t mode)

  {

  	struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk);

  	struct scsi_device *sdev;
  	int retval;

  	if (!sdkp)

  		return -ENXIO;

  	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open
  "));

  
  	sdev = sdkp->device;

  	retval = scsi_autopm_get_device(sdev);
  	if (retval)
  		goto error_autopm;

  	/*
  	 * 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(bdev);

  
  	/*
  	 * If the drive is empty, just let the open fail.
  	 */
  	retval = -ENOMEDIUM;

  	if (sdev->removable && !sdkp->media_present && !(mode & FMODE_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 && (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 ((atomic_inc_return(&sdkp->openers) == 1) && sdev->removable) {

  		if (scsi_block_when_processing_errors(sdev))
  			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
  	}
  
  	return 0;
  
  error_out:

  	scsi_autopm_put_device(sdev);
  error_autopm:

  	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.

   *
   *	Locking: called with bdev->bd_mutex held.

   **/

  static int sd_release(struct gendisk *disk, fmode_t mode)

  {

  	struct scsi_disk *sdkp = scsi_disk(disk);
  	struct scsi_device *sdev = sdkp->device;

  	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_release
  "));

  	if (atomic_dec_return(&sdkp->openers) == 0 && 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_autopm_put_device(sdev);

  	scsi_disk_put(sdkp);
  	return 0;
  }

  static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo)

  {
  	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);

  	geo->heads = diskinfo[0];
  	geo->sectors = diskinfo[1];
  	geo->cylinders = diskinfo[2];

  	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 positive 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 subsystem.

   **/

  static int sd_ioctl(struct block_device *bdev, fmode_t mode,

  		    unsigned int cmd, unsigned long arg)
  {

  	struct gendisk *disk = bdev->bd_disk;

  	struct scsi_disk *sdkp = scsi_disk(disk);
  	struct scsi_device *sdp = sdkp->device;

  	void __user *p = (void __user *)arg;
  	int error;
      

  	SCSI_LOG_IOCTL(1, sd_printk(KERN_INFO, sdkp, "sd_ioctl: disk=%s, "
  				    "cmd=0x%x
  ", 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,

  					(mode & FMODE_NDELAY) != 0);

  	if (!scsi_block_when_processing_errors(sdp) || !error)

  		goto out;

  	/*
  	 * 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:

  			error = scsi_ioctl(sdp, cmd, p);
  			break;

  		default:

  			error = scsi_cmd_ioctl(disk->queue, disk, mode, cmd, p);

  			if (error != -ENOTTY)

  				break;
  			error = scsi_ioctl(sdp, cmd, p);
  			break;

  	}

  out:

  	return error;

  }
  
  static void set_media_not_present(struct scsi_disk *sdkp)
  {

  	if (sdkp->media_present)
  		sdkp->device->changed = 1;
  
  	if (sdkp->device->removable) {
  		sdkp->media_present = 0;
  		sdkp->capacity = 0;
  	}
  }
  
  static int media_not_present(struct scsi_disk *sdkp,
  			     struct scsi_sense_hdr *sshdr)
  {
  	if (!scsi_sense_valid(sshdr))
  		return 0;
  
  	/* not invoked for commands that could return deferred errors */
  	switch (sshdr->sense_key) {
  	case UNIT_ATTENTION:
  	case NOT_READY:
  		/* medium not present */
  		if (sshdr->asc == 0x3A) {
  			set_media_not_present(sdkp);
  			return 1;
  		}
  	}
  	return 0;

  }
  
  /**

   *	sd_check_events - check media events
   *	@disk: kernel device descriptor
   *	@clearing: disk events currently being cleared

   *

   *	Returns mask of DISK_EVENT_*.

   *
   *	Note: this function is invoked from the block subsystem.
   **/

  static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)

  {
  	struct scsi_disk *sdkp = scsi_disk(disk);
  	struct scsi_device *sdp = sdkp->device;

  	struct scsi_sense_hdr *sshdr = NULL;

  	int retval;

  	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events
  "));

  
  	/*
  	 * 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)) {
  		set_media_not_present(sdkp);

  		goto out;
  	}

  
  	/*
  	 * 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)) {
  		sshdr  = kzalloc(sizeof(*sshdr), GFP_KERNEL);
  		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES,
  					      sshdr);
  	}

  	/* failed to execute TUR, assume media not present */
  	if (host_byte(retval)) {

  		set_media_not_present(sdkp);

  		goto out;
  	}

  	if (media_not_present(sdkp, sshdr))
  		goto out;

  	/*
  	 * For removable scsi disk we have to recognise the presence

  	 * of a disk in the drive.

  	 */

  	if (!sdkp->media_present)
  		sdp->changed = 1;

  	sdkp->media_present = 1;

  out:

  	/*

  	 * sdp->changed is set under the following conditions:

  	 *

  	 *	Medium present state has changed in either direction.
  	 *	Device has indicated UNIT_ATTENTION.

  	 */

  	kfree(sshdr);

  	retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
  	sdp->changed = 0;

  	return retval;

  }

  static int sd_sync_cache(struct scsi_disk *sdkp)

  {

  	int retries, res;

  	struct scsi_device *sdp = sdkp->device;

  	struct scsi_sense_hdr sshdr;

  
  	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.
  		 */

  		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,

  				       SD_FLUSH_TIMEOUT, SD_MAX_RETRIES, NULL);

  		if (res == 0)

  			break;
  	}

  	if (res) {
  		sd_print_result(sdkp, res);
  		if (driver_byte(res) & DRIVER_SENSE)
  			sd_print_sense_hdr(sdkp, &sshdr);

  	}

  	if (res)
  		return -EIO;
  	return 0;

  }

  static void sd_rescan(struct device *dev)
  {

  	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
  
  	if (sdkp) {

  		revalidate_disk(sdkp->disk);

  		scsi_disk_put(sdkp);
  	}

  }
  
  
  #ifdef CONFIG_COMPAT
  /* 
   * This gets directly called from VFS. When the ioctl 
   * is not recognized we go back to the other translation paths. 
   */

  static int sd_compat_ioctl(struct block_device *bdev, fmode_t mode,
  			   unsigned int cmd, unsigned long arg)

  {

  	struct scsi_device *sdev = scsi_disk(bdev->bd_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 const struct block_device_operations sd_fops = {

  	.owner			= THIS_MODULE,

  	.open			= sd_open,
  	.release		= sd_release,

  	.ioctl			= sd_ioctl,

  	.getgeo			= sd_getgeo,

  #ifdef CONFIG_COMPAT

  	.compat_ioctl		= sd_compat_ioctl,

  #endif

  	.check_events		= sd_check_events,

  	.revalidate_disk	= sd_revalidate_disk,

  	.unlock_native_capacity	= sd_unlock_native_capacity,

  };

  static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
  {

  	u64 start_lba = blk_rq_pos(scmd->request);
  	u64 end_lba = blk_rq_pos(scmd->request) + (scsi_bufflen(scmd) / 512);

  	u64 bad_lba;
  	int info_valid;

  	/*
  	 * resid is optional but mostly filled in.  When it's unused,
  	 * its value is zero, so we assume the whole buffer transferred
  	 */
  	unsigned int transferred = scsi_bufflen(scmd) - scsi_get_resid(scmd);
  	unsigned int good_bytes;

  	if (scmd->request->cmd_type != REQ_TYPE_FS)

  		return 0;
  
  	info_valid = scsi_get_sense_info_fld(scmd->sense_buffer,
  					     SCSI_SENSE_BUFFERSIZE,
  					     &bad_lba);
  	if (!info_valid)
  		return 0;
  
  	if (scsi_bufflen(scmd) <= scmd->device->sector_size)
  		return 0;
  
  	if (scmd->device->sector_size < 512) {
  		/* only legitimate sector_size here is 256 */
  		start_lba <<= 1;
  		end_lba <<= 1;
  	} else {
  		/* be careful ... don't want any overflows */
  		u64 factor = scmd->device->sector_size / 512;
  		do_div(start_lba, factor);
  		do_div(end_lba, factor);
  	}
  
  	/* The bad lba was reported incorrectly, we have no idea where
  	 * the error is.
  	 */
  	if (bad_lba < start_lba  || bad_lba >= end_lba)
  		return 0;
  
  	/* This computation should always be done in terms of
  	 * the resolution of the device's medium.
  	 */

  	good_bytes = (bad_lba - start_lba) * scmd->device->sector_size;
  	return min(good_bytes, transferred);

  }

  /**

   *	sd_done - 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 int sd_done(struct scsi_cmnd *SCpnt)

  {
  	int result = SCpnt->result;

  	unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);

  	struct scsi_sense_hdr sshdr;

  	struct scsi_disk *sdkp = scsi_disk(SCpnt->request->rq_disk);

  	int sense_valid = 0;
  	int sense_deferred = 0;

  	unsigned char op = SCpnt->cmnd[0];

  	if ((SCpnt->request->cmd_flags & REQ_DISCARD) && !result)
  		scsi_set_resid(SCpnt, 0);

  	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, scsi_print_result(SCpnt));

  	if (sense_valid) {

  		SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,

  						   "sd_done: sb[respc,sk,asc,"

  						   "ascq]=%x,%x,%x,%x
  ",
  						   sshdr.response_code,
  						   sshdr.sense_key, sshdr.asc,
  						   sshdr.ascq));

  	}
  #endif

  	if (driver_byte(result) != DRIVER_SENSE &&
  	    (!sense_valid || sense_deferred))
  		goto out;
  
  	switch (sshdr.sense_key) {
  	case HARDWARE_ERROR:
  	case MEDIUM_ERROR:

  		good_bytes = sd_completed_bytes(SCpnt);

  		break;
  	case RECOVERED_ERROR:

  		good_bytes = scsi_bufflen(SCpnt);
  		break;

  	case NO_SENSE:
  		/* This indicates a false check condition, so ignore it.  An
  		 * unknown amount of data was transferred so treat it as an
  		 * error.
  		 */
  		scsi_print_sense("sd", SCpnt);
  		SCpnt->result = 0;
  		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
  		break;

  	case ABORTED_COMMAND:
  		if (sshdr.asc == 0x10)  /* DIF: Target detected corruption */
  			good_bytes = sd_completed_bytes(SCpnt);
  		break;
  	case ILLEGAL_REQUEST:
  		if (sshdr.asc == 0x10)  /* DIX: Host detected corruption */

  			good_bytes = sd_completed_bytes(SCpnt);

  		/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
  		if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
  		    (op == UNMAP || op == WRITE_SAME_16 || op == WRITE_SAME))
  			sd_config_discard(sdkp, SD_LBP_DISABLE);

  		break;
  	default:
  		break;

  	}

   out:

  	if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
  		sd_dif_complete(SCpnt, good_bytes);

  	if (scsi_host_dif_capable(sdkp->device->host, sdkp->protection_type)

  	    == SD_DIF_TYPE2_PROTECTION && SCpnt->cmnd != SCpnt->request->cmd) {
  
  		/* We have to print a failed command here as the
  		 * extended CDB gets freed before scsi_io_completion()
  		 * is called.
  		 */
  		if (result)
  			scsi_print_command(SCpnt);

  		mempool_free(SCpnt->cmnd, sd_cdb_pool);

  		SCpnt->cmnd = NULL;
  		SCpnt->cmd_len = 0;
  	}

  	return good_bytes;

  }

  /*
   * spinup disk - called only in sd_revalidate_disk()
   */
  static void

  sd_spinup_disk(struct scsi_disk *sdkp)

  {

  	unsigned char cmd[10];

  	unsigned long spintime_expire = 0;

  	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);

  			the_result = scsi_execute_req(sdkp->device, cmd,
  						      DMA_NONE, NULL, 0,
  						      &sshdr, SD_TIMEOUT,

  						      SD_MAX_RETRIES, NULL);

  			/*
  			 * If the drive has indicated to us that it
  			 * doesn't have any media in it, don't bother
  			 * with any more polling.
  			 */
  			if (media_not_present(sdkp, &sshdr))
  				return;

  			if (the_result)

  				sense_valid = scsi_sense_valid(&sshdr);

  			retries++;
  		} while (retries < 3 && 
  			 (!scsi_status_is_good(the_result) ||
  			  ((driver_byte(the_result) & DRIVER_SENSE) &&
  			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));

  		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)) {
  				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready
  ");
  				sd_print_result(sdkp, the_result);
  			}

  			break;
  		}
  					
  		/*
  		 * The device does not want the automatic start to be issued.
  		 */

  		if (sdkp->device->no_start_on_add)

  			break;

  		if (sense_valid && sshdr.sense_key == NOT_READY) {
  			if (sshdr.asc == 4 && sshdr.ascq == 3)
  				break;	/* manual intervention required */
  			if (sshdr.asc == 4 && sshdr.ascq == 0xb)
  				break;	/* standby */
  			if (sshdr.asc == 4 && sshdr.ascq == 0xc)
  				break;	/* unavailable */
  			/*
  			 * Issue command to spin up drive when not ready
  			 */

  			if (!spintime) {

  				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");

  				cmd[0] = START_STOP;
  				cmd[1] = 1;	/* Return immediately */
  				memset((void *) &cmd[2], 0, 8);
  				cmd[4] = 1;	/* Start spin cycle */

  				if (sdkp->device->start_stop_pwr_cond)
  					cmd[4] |= 1 << 4;

  				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
  						 NULL, 0, &sshdr,

  						 SD_TIMEOUT, SD_MAX_RETRIES,
  						 NULL);

  				spintime_expire = jiffies + 100 * HZ;
  				spintime = 1;

  			}

  			/* Wait 1 second for next try */
  			msleep(1000);
  			printk(".");

  
  		/*
  		 * 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);

  		} else {
  			/* we don't understand the sense code, so it's
  			 * probably pointless to loop */
  			if(!spintime) {

  				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready
  ");
  				sd_print_sense_hdr(sdkp, &sshdr);

  			}
  			break;
  		}
  				

  	} while (spintime && time_before_eq(jiffies, spintime_expire));

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

  
  /*
   * Determine whether disk supports Data Integrity Field.
   */

  static void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)

  {
  	struct scsi_device *sdp = sdkp->device;
  	u8 type;
  
  	if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)

  		return;
  
  	type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
  
  	if (type == sdkp->protection_type || !sdkp->first_scan)
  		return;

  	sdkp->protection_type = type;

  	if (type > SD_DIF_TYPE3_PROTECTION) {

  		sd_printk(KERN_ERR, sdkp, "formatted with unsupported "	\
  			  "protection type %u. Disabling disk!
  ", type);
  		sdkp->capacity = 0;
  		return;

  	}

  	if (scsi_host_dif_capable(sdp->host, type))
  		sd_printk(KERN_NOTICE, sdkp,
  			  "Enabling DIF Type %u protection
  ", type);
  	else
  		sd_printk(KERN_NOTICE, sdkp,
  			  "Disabling DIF Type %u protection
  ", type);

  }

  static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
  			struct scsi_sense_hdr *sshdr, int sense_valid,
  			int the_result)
  {
  	sd_print_result(sdkp, the_result);
  	if (driver_byte(the_result) & DRIVER_SENSE)
  		sd_print_sense_hdr(sdkp, sshdr);
  	else
  		sd_printk(KERN_NOTICE, sdkp, "Sense not available.
  ");
  
  	/*
  	 * 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)

  		set_media_not_present(sdkp);

  
  	/*
  	 * We used to set media_present to 0 here to indicate no media
  	 * in the drive, but some drives fail read capacity even with
  	 * media present, so we can't do that.
  	 */
  	sdkp->capacity = 0; /* unknown mapped to zero - as usual */
  }
  
  #define RC16_LEN 32
  #if RC16_LEN > SD_BUF_SIZE
  #error RC16_LEN must not be more than SD_BUF_SIZE
  #endif

  #define READ_CAPACITY_RETRIES_ON_RESET	10

  static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
  						unsigned char *buffer)

  {

  	unsigned char cmd[16];

  	struct scsi_sense_hdr sshdr;
  	int sense_valid = 0;

  	int the_result;

  	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;

  	unsigned int alignment;

  	unsigned long long lba;
  	unsigned sector_size;

  	if (sdp->no_read_capacity_16)
  		return -EINVAL;

  	do {

  		memset(cmd, 0, 16);
  		cmd[0] = SERVICE_ACTION_IN;
  		cmd[1] = SAI_READ_CAPACITY_16;
  		cmd[13] = RC16_LEN;
  		memset(buffer, 0, RC16_LEN);

  		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,

  					buffer, RC16_LEN, &sshdr,
  					SD_TIMEOUT, SD_MAX_RETRIES, NULL);

  		if (media_not_present(sdkp, &sshdr))

  			return -ENODEV;

  		if (the_result) {

  			sense_valid = scsi_sense_valid(&sshdr);

  			if (sense_valid &&
  			    sshdr.sense_key == ILLEGAL_REQUEST &&
  			    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
  			    sshdr.ascq == 0x00)
  				/* Invalid Command Operation Code or
  				 * Invalid Field in CDB, just retry
  				 * silently with RC10 */
  				return -EINVAL;

  			if (sense_valid &&
  			    sshdr.sense_key == UNIT_ATTENTION &&
  			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
  				/* Device reset might occur several times,
  				 * give it one more chance */
  				if (--reset_retries > 0)
  					continue;

  		}

  		retries--;
  
  	} while (the_result && retries);

  	if (the_result) {

  		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed
  ");

  		read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
  		return -EINVAL;
  	}

  	sector_size = get_unaligned_be32(&buffer[8]);
  	lba = get_unaligned_be64(&buffer[0]);

  
  	sd_read_protection_type(sdkp, buffer);
  
  	if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
  		sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
  			"kernel compiled with support for large block "
  			"devices.
  ");
  		sdkp->capacity = 0;
  		return -EOVERFLOW;
  	}

  	/* Logical blocks per physical block exponent */

  	sdkp->physical_block_size = (1 << (buffer[13] & 0xf)) * sector_size;

  
  	/* Lowest aligned logical block */
  	alignment = ((buffer[14] & 0x3f) << 8 | buffer[15]) * sector_size;
  	blk_queue_alignment_offset(sdp->request_queue, alignment);
  	if (alignment && sdkp->first_scan)
  		sd_printk(KERN_NOTICE, sdkp,
  			  "physical block alignment offset: %u
  ", alignment);

  	if (buffer[14] & 0x80) { /* LBPME */
  		sdkp->lbpme = 1;

  		if (buffer[14] & 0x40) /* LBPRZ */
  			sdkp->lbprz = 1;

  		sd_config_discard(sdkp, SD_LBP_WS16);

  	}

  	sdkp->capacity = lba + 1;
  	return sector_size;
  }
  
  static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
  						unsigned char *buffer)
  {
  	unsigned char cmd[16];
  	struct scsi_sense_hdr sshdr;
  	int sense_valid = 0;
  	int the_result;

  	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;

  	sector_t lba;
  	unsigned sector_size;
  
  	do {
  		cmd[0] = READ_CAPACITY;
  		memset(&cmd[1], 0, 9);
  		memset(buffer, 0, 8);
  
  		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
  					buffer, 8, &sshdr,
  					SD_TIMEOUT, SD_MAX_RETRIES, NULL);
  
  		if (media_not_present(sdkp, &sshdr))
  			return -ENODEV;

  		if (the_result) {

  			sense_valid = scsi_sense_valid(&sshdr);

  			if (sense_valid &&
  			    sshdr.sense_key == UNIT_ATTENTION &&
  			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
  				/* Device reset might occur several times,
  				 * give it one more chance */
  				if (--reset_retries > 0)
  					continue;
  		}

  		retries--;
  
  	} while (the_result && retries);
  
  	if (the_result) {
  		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed
  ");
  		read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
  		return -EINVAL;
  	}

  	sector_size = get_unaligned_be32(&buffer[4]);
  	lba = get_unaligned_be32(&buffer[0]);

  	if (sdp->no_read_capacity_16 && (lba == 0xffffffff)) {
  		/* Some buggy (usb cardreader) devices return an lba of
  		   0xffffffff when the want to report a size of 0 (with
  		   which they really mean no media is present) */
  		sdkp->capacity = 0;

  		sdkp->physical_block_size = sector_size;

  		return sector_size;
  	}

  	if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
  		sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
  			"kernel compiled with support for large block "
  			"devices.
  ");
  		sdkp->capacity = 0;
  		return -EOVERFLOW;
  	}
  
  	sdkp->capacity = lba + 1;

  	sdkp->physical_block_size = sector_size;

  	return sector_size;
  }

  static int sd_try_rc16_first(struct scsi_device *sdp)
  {

  	if (sdp->host->max_cmd_len < 16)
  		return 0;

  	if (sdp->scsi_level > SCSI_SPC_2)
  		return 1;
  	if (scsi_device_protection(sdp))
  		return 1;
  	return 0;
  }

  /*
   * read disk capacity
   */
  static void
  sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
  {
  	int sector_size;
  	struct scsi_device *sdp = sdkp->device;

  	sector_t old_capacity = sdkp->capacity;

  	if (sd_try_rc16_first(sdp)) {

  		sector_size = read_capacity_16(sdkp, sdp, buffer);
  		if (sector_size == -EOVERFLOW)

  			goto got_data;

  		if (sector_size == -ENODEV)
  			return;
  		if (sector_size < 0)
  			sector_size = read_capacity_10(sdkp, sdp, buffer);

  		if (sector_size < 0)
  			return;

  	} else {

  		sector_size = read_capacity_10(sdkp, sdp, buffer);
  		if (sector_size == -EOVERFLOW)
  			goto got_data;
  		if (sector_size < 0)
  			return;
  		if ((sizeof(sdkp->capacity) > 4) &&
  		    (sdkp->capacity > 0xffffffffULL)) {
  			int old_sector_size = sector_size;
  			sd_printk(KERN_NOTICE, sdkp, "Very big device. "
  					"Trying to use READ CAPACITY(16).
  ");
  			sector_size = read_capacity_16(sdkp, sdp, buffer);
  			if (sector_size < 0) {
  				sd_printk(KERN_NOTICE, sdkp,
  					"Using 0xffffffff as device size
  ");
  				sdkp->capacity = 1 + (sector_t) 0xffffffff;
  				sector_size = old_sector_size;
  				goto got_data;
  			}
  		}
  	}

  	/* Some devices are known to return the total number of blocks,
  	 * not the highest block number.  Some devices have versions
  	 * which do this and others which do not.  Some devices we might
  	 * suspect of doing this but we don't know for certain.
  	 *
  	 * If we know the reported capacity is wrong, decrement it.  If
  	 * we can only guess, then assume the number of blocks is even
  	 * (usually true but not always) and err on the side of lowering
  	 * the capacity.
  	 */
  	if (sdp->fix_capacity ||
  	    (sdp->guess_capacity && (sdkp->capacity & 0x01))) {
  		sd_printk(KERN_INFO, sdkp, "Adjusting the sector count "
  				"from its reported value: %llu
  ",
  				(unsigned long long) sdkp->capacity);

  		--sdkp->capacity;

  	}

  got_data:
  	if (sector_size == 0) {
  		sector_size = 512;

  		sd_printk(KERN_NOTICE, sdkp, "Sector size 0 reported, "
  			  "assuming 512.
  ");

  	}
  
  	if (sector_size != 512 &&
  	    sector_size != 1024 &&
  	    sector_size != 2048 &&
  	    sector_size != 4096 &&
  	    sector_size != 256) {

  		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.
  ",
  			  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;
  	}

  	blk_queue_logical_block_size(sdp->request_queue, sector_size);

  	{

  		char cap_str_2[10], cap_str_10[10];

  		u64 sz = (u64)sdkp->capacity << ilog2(sector_size);

  		string_get_size(sz, STRING_UNITS_2, cap_str_2,
  				sizeof(cap_str_2));
  		string_get_size(sz, STRING_UNITS_10, cap_str_10,
  				sizeof(cap_str_10));

  		if (sdkp->first_scan || old_capacity != sdkp->capacity) {

  			sd_printk(KERN_NOTICE, sdkp,

  				  "%llu %d-byte logical blocks: (%s/%s)
  ",

  				  (unsigned long long)sdkp->capacity,
  				  sector_size, cap_str_10, cap_str_2);

  			if (sdkp->physical_block_size != sector_size)

  				sd_printk(KERN_NOTICE, sdkp,
  					  "%u-byte physical blocks
  ",

  					  sdkp->physical_block_size);

  		}

  	}
  
  	/* 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;

  	blk_queue_physical_block_size(sdp->request_queue,
  				      sdkp->physical_block_size);

  	sdkp->device->sector_size = sector_size;
  }
  
  /* called with buffer of length 512 */
  static inline int

  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)

  {

  	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,

  			       SD_TIMEOUT, SD_MAX_RETRIES, data,

  			       sshdr);

  }
  
  /*
   * read write protect setting, if possible - called only in sd_revalidate_disk()

   * called with buffer of length SD_BUF_SIZE

   */
  static void

  sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)

  {

  	int res;

  	struct scsi_device *sdp = sdkp->device;

  	struct scsi_mode_data data;

  	int old_wp = sdkp->write_prot;

  
  	set_disk_ro(sdkp->disk, 0);

  	if (sdp->skip_ms_page_3f) {

  		sd_printk(KERN_NOTICE, sdkp, "Assuming Write Enabled
  ");

  		return;
  	}

  	if (sdp->use_192_bytes_for_3f) {
  		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);

  	} 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.
  		 */

  		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);

  
  		/*
  		 * 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))

  			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);

  
  		/*
  		 * Third attempt: ask 255 bytes, as we did earlier.
  		 */
  		if (!scsi_status_is_good(res))

  			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
  					       &data, NULL);

  	}
  
  	if (!scsi_status_is_good(res)) {

  		sd_printk(KERN_WARNING, sdkp,
  			  "Test WP failed, assume Write Enabled
  ");

  	} else {
  		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
  		set_disk_ro(sdkp->disk, sdkp->write_prot);

  		if (sdkp->first_scan || old_wp != sdkp->write_prot) {
  			sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s
  ",
  				  sdkp->write_prot ? "on" : "off");
  			sd_printk(KERN_DEBUG, sdkp,
  				  "Mode Sense: %02x %02x %02x %02x
  ",
  				  buffer[0], buffer[1], buffer[2], buffer[3]);
  		}

  	}
  }
  
  /*
   * sd_read_cache_type - called only from sd_revalidate_disk()

   * called with buffer of length SD_BUF_SIZE

   */
  static void

  sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)

  {

  	int len = 0, res;

  	struct scsi_device *sdp = sdkp->device;

  	int dbd;
  	int modepage;

  	int first_len;

  	struct scsi_mode_data data;
  	struct scsi_sense_hdr sshdr;

  	int old_wce = sdkp->WCE;
  	int old_rcd = sdkp->RCD;
  	int old_dpofua = sdkp->DPOFUA;

  	first_len = 4;
  	if (sdp->skip_ms_page_8) {
  		if (sdp->type == TYPE_RBC)
  			goto defaults;
  		else {
  			if (sdp->skip_ms_page_3f)
  				goto defaults;
  			modepage = 0x3F;
  			if (sdp->use_192_bytes_for_3f)
  				first_len = 192;
  			dbd = 0;
  		}
  	} else if (sdp->type == TYPE_RBC) {

  		modepage = 6;
  		dbd = 8;
  	} else {
  		modepage = 8;
  		dbd = 0;
  	}

  	/* cautiously ask */

  	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, first_len,
  			&data, &sshdr);

  
  	if (!scsi_status_is_good(res))
  		goto bad_sense;

  	if (!data.header_length) {
  		modepage = 6;

  		first_len = 0;

  		sd_printk(KERN_ERR, sdkp, "Missing header in MODE_SENSE response
  ");

  	}

  	/* 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;

  	else if (len > SD_BUF_SIZE) {
  		sd_printk(KERN_NOTICE, sdkp, "Truncating mode parameter "
  			  "data from %d to %d bytes
  ", len, SD_BUF_SIZE);
  		len = SD_BUF_SIZE;
  	}
  	if (modepage == 0x3F && sdp->use_192_bytes_for_3f)
  		len = 192;

  
  	/* Get the data */

  	if (len > first_len)
  		res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len,
  				&data, &sshdr);

  
  	if (scsi_status_is_good(res)) {

  		int offset = data.header_length + data.block_descriptor_length;

  		while (offset < len) {
  			u8 page_code = buffer[offset] & 0x3F;
  			u8 spf       = buffer[offset] & 0x40;
  
  			if (page_code == 8 || page_code == 6) {
  				/* We're interested only in the first 3 bytes.
  				 */
  				if (len - offset <= 2) {
  					sd_printk(KERN_ERR, sdkp, "Incomplete "
  						  "mode parameter data
  ");
  					goto defaults;
  				} else {
  					modepage = page_code;
  					goto Page_found;
  				}
  			} else {
  				/* Go to the next page */
  				if (spf && len - offset > 3)
  					offset += 4 + (buffer[offset+2] << 8) +
  						buffer[offset+3];
  				else if (!spf && len - offset > 1)
  					offset += 2 + buffer[offset+1];
  				else {
  					sd_printk(KERN_ERR, sdkp, "Incomplete "
  						  "mode parameter data
  ");
  					goto defaults;
  				}
  			}

  		}

  		if (modepage == 0x3F) {
  			sd_printk(KERN_ERR, sdkp, "No Caching mode page "
  				  "present
  ");
  			goto defaults;
  		} else if ((buffer[offset] & 0x3f) != modepage) {

  			sd_printk(KERN_ERR, sdkp, "Got wrong page
  ");

  			goto defaults;
  		}

  	Page_found:

  		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;
  		}

  		sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
  		if (sdkp->DPOFUA && !sdkp->device->use_10_for_rw) {

  			sd_printk(KERN_NOTICE, sdkp,
  				  "Uses READ/WRITE(6), disabling FUA
  ");

  			sdkp->DPOFUA = 0;
  		}

  		if (sdkp->first_scan || old_wce != sdkp->WCE ||
  		    old_rcd != sdkp->RCD || old_dpofua != sdkp->DPOFUA)
  			sd_printk(KERN_NOTICE, sdkp,
  				  "Write cache: %s, read cache: %s, %s
  ",
  				  sdkp->WCE ? "enabled" : "disabled",
  				  sdkp->RCD ? "disabled" : "enabled",
  				  sdkp->DPOFUA ? "supports DPO and FUA"
  				  : "doesn't support DPO or FUA");

  
  		return;
  	}
  
  bad_sense: