/*
   *      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 <linux/pr.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_priv.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 void sd_config_write_same(struct scsi_disk *);

  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_system(struct device *);
  static int sd_suspend_runtime(struct device *);

  static int sd_resume(struct device *);
  static void sd_rescan(struct device *);

  static int sd_init_command(struct scsi_cmnd *SCpnt);
  static void sd_uninit_command(struct scsi_cmnd *SCpnt);

  static int sd_done(struct scsi_cmnd *);

  static int sd_eh_action(struct scsi_cmnd *, int);

  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(const struct scsi_disk *, const char *, 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 void sd_set_flush_flag(struct scsi_disk *sdkp)
  {
  	unsigned flush = 0;
  
  	if (sdkp->WCE) {
  		flush |= REQ_FLUSH;
  		if (sdkp->DPOFUA)
  			flush |= REQ_FUA;
  	}
  
  	blk_queue_flush(sdkp->disk->queue, flush);
  }

  static ssize_t

  cache_type_store(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;

  	static const char temp[] = "temporary ";

  	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;

  	if (strncmp(buf, temp, sizeof(temp) - 1) == 0) {
  		buf += sizeof(temp) - 1;
  		sdkp->cache_override = 1;
  	} else {
  		sdkp->cache_override = 0;
  	}

  	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) && !sdkp->write_prot ? 1 : 0;

  
  	if (sdkp->cache_override) {
  		sdkp->WCE = wce;
  		sdkp->RCD = rcd;

  		sd_set_flush_flag(sdkp);

  		return count;
  	}

  	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;

  	buffer_data[0] &= ~0x80;

  
  	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

  manage_start_stop_show(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
  manage_start_stop_store(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 DEVICE_ATTR_RW(manage_start_stop);

  static ssize_t

  allow_restart_show(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
  allow_restart_store(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 DEVICE_ATTR_RW(allow_restart);

  static ssize_t

  cache_type_show(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 DEVICE_ATTR_RW(cache_type);

  static ssize_t

  FUA_show(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 DEVICE_ATTR_RO(FUA);

  static ssize_t

  protection_type_show(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

  protection_type_store(struct device *dev, struct device_attribute *attr,
  		      const char *buf, size_t count)

  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  	unsigned int val;
  	int err;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	err = kstrtouint(buf, 10, &val);
  
  	if (err)
  		return err;
  
  	if (val >= 0 && val <= SD_DIF_TYPE3_PROTECTION)
  		sdkp->protection_type = val;
  
  	return count;
  }

  static DEVICE_ATTR_RW(protection_type);

  
  static ssize_t

  protection_mode_show(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 DEVICE_ATTR_RO(protection_mode);

  
  static ssize_t

  app_tag_own_show(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 DEVICE_ATTR_RO(app_tag_own);

  static ssize_t

  thin_provisioning_show(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 DEVICE_ATTR_RO(thin_provisioning);

  
  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

  provisioning_mode_show(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

  provisioning_mode_store(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 DEVICE_ATTR_RW(provisioning_mode);

  static ssize_t

  max_medium_access_timeouts_show(struct device *dev,
  				struct device_attribute *attr, char *buf)

  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  
  	return snprintf(buf, 20, "%u
  ", sdkp->max_medium_access_timeouts);
  }
  
  static ssize_t

  max_medium_access_timeouts_store(struct device *dev,
  				 struct device_attribute *attr, const char *buf,
  				 size_t count)

  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  	int err;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	err = kstrtouint(buf, 10, &sdkp->max_medium_access_timeouts);
  
  	return err ? err : count;
  }

  static DEVICE_ATTR_RW(max_medium_access_timeouts);

  static ssize_t

  max_write_same_blocks_show(struct device *dev, struct device_attribute *attr,
  			   char *buf)

  {
  	struct scsi_disk *sdkp = to_scsi_disk(dev);
  
  	return snprintf(buf, 20, "%u
  ", sdkp->max_ws_blocks);
  }
  
  static ssize_t

  max_write_same_blocks_store(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;
  	unsigned long max;
  	int err;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	if (sdp->type != TYPE_DISK)
  		return -EINVAL;
  
  	err = kstrtoul(buf, 10, &max);
  
  	if (err)
  		return err;
  
  	if (max == 0)
  		sdp->no_write_same = 1;

  	else if (max <= SD_MAX_WS16_BLOCKS) {
  		sdp->no_write_same = 0;

  		sdkp->max_ws_blocks = max;

  	}

  
  	sd_config_write_same(sdkp);
  
  	return count;
  }

  static DEVICE_ATTR_RW(max_write_same_blocks);
  
  static struct attribute *sd_disk_attrs[] = {
  	&dev_attr_cache_type.attr,
  	&dev_attr_FUA.attr,
  	&dev_attr_allow_restart.attr,
  	&dev_attr_manage_start_stop.attr,
  	&dev_attr_protection_type.attr,
  	&dev_attr_protection_mode.attr,
  	&dev_attr_app_tag_own.attr,
  	&dev_attr_thin_provisioning.attr,
  	&dev_attr_provisioning_mode.attr,
  	&dev_attr_max_write_same_blocks.attr,
  	&dev_attr_max_medium_access_timeouts.attr,
  	NULL,

  };

  ATTRIBUTE_GROUPS(sd_disk);

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

  	.dev_release	= scsi_disk_release,

  	.dev_groups	= sd_disk_groups,

  };

  static const struct dev_pm_ops sd_pm_ops = {

  	.suspend		= sd_suspend_system,

  	.resume			= sd_resume,

  	.poweroff		= sd_suspend_system,

  	.restore		= sd_resume,

  	.runtime_suspend	= sd_suspend_runtime,

  	.runtime_resume		= sd_resume,
  };

  static struct scsi_driver sd_template = {

  	.gendrv = {
  		.name		= "sd",

  		.owner		= THIS_MODULE,

  		.probe		= sd_probe,
  		.remove		= sd_remove,
  		.shutdown	= sd_shutdown,

  		.pm		= &sd_pm_ops,

  	},
  	.rescan			= sd_rescan,

  	.init_command		= sd_init_command,
  	.uninit_command		= sd_uninit_command,

  	.done			= sd_done,

  	.eh_action		= sd_eh_action,

  };
  
  /*

   * Dummy kobj_map->probe function.
   * The default ->probe function will call modprobe, which is
   * pointless as this module is already loaded.
   */
  static struct kobject *sd_default_probe(dev_t devt, int *partno, void *data)
  {
  	return NULL;
  }
  
  /*

   * 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;

  	mutex_lock(&sd_ref_mutex);

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

  			get_device(&sdkp->dev);

  		else
  			sdkp = NULL;
  	}

  	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 unsigned char sd_setup_protect_cmnd(struct scsi_cmnd *scmd,
  					   unsigned int dix, unsigned int dif)

  {

  	struct bio *bio = scmd->request->bio;
  	unsigned int prot_op = sd_prot_op(rq_data_dir(scmd->request), dix, dif);
  	unsigned int protect = 0;
  
  	if (dix) {				/* DIX Type 0, 1, 2, 3 */
  		if (bio_integrity_flagged(bio, BIP_IP_CHECKSUM))
  			scmd->prot_flags |= SCSI_PROT_IP_CHECKSUM;
  
  		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
  			scmd->prot_flags |= SCSI_PROT_GUARD_CHECK;
  	}
  
  	if (dif != SD_DIF_TYPE3_PROTECTION) {	/* DIX/DIF Type 0, 1, 2 */
  		scmd->prot_flags |= SCSI_PROT_REF_INCREMENT;
  
  		if (bio_integrity_flagged(bio, BIP_CTRL_NOCHECK) == false)
  			scmd->prot_flags |= SCSI_PROT_REF_CHECK;
  	}
  
  	if (dif) {				/* DIX/DIF Type 1, 2, 3 */
  		scmd->prot_flags |= SCSI_PROT_TRANSFER_PI;
  
  		if (bio_integrity_flagged(bio, BIP_DISK_NOCHECK))
  			protect = 3 << 5;	/* Disable target PI checking */
  		else
  			protect = 1 << 5;	/* Enable target PI checking */

  	}
  
  	scsi_set_prot_op(scmd, prot_op);
  	scsi_set_prot_type(scmd, dif);

  	scmd->prot_flags &= sd_prot_flag_mask(prot_op);
  
  	return protect;

  }

  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 = 0;

  
  	/*
  	 * When LBPRZ is reported, discard alignment and granularity
  	 * must be fixed to the logical block size. Otherwise the block
  	 * layer will drop misaligned portions of the request which can
  	 * lead to data corruption. If LBPRZ is not set, we honor the
  	 * device preference.
  	 */
  	if (sdkp->lbprz) {
  		q->limits.discard_alignment = 0;
  		q->limits.discard_granularity = 1;
  	} else {
  		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);
  	}

  	sdkp->provisioning_mode = mode;

  	switch (mode) {
  
  	case SD_LBP_DISABLE:

  		blk_queue_max_discard_sectors(q, 0);

  		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
  		return;
  
  	case SD_LBP_UNMAP:

  		max_blocks = min_not_zero(sdkp->max_unmap_blocks,
  					  (u32)SD_MAX_WS16_BLOCKS);

  		break;
  
  	case SD_LBP_WS16:

  		max_blocks = min_not_zero(sdkp->max_ws_blocks,
  					  (u32)SD_MAX_WS16_BLOCKS);

  		q->limits.discard_zeroes_data = sdkp->lbprz;

  		break;
  
  	case SD_LBP_WS10:

  		max_blocks = min_not_zero(sdkp->max_ws_blocks,
  					  (u32)SD_MAX_WS10_BLOCKS);

  		q->limits.discard_zeroes_data = sdkp->lbprz;

  		break;
  
  	case SD_LBP_ZERO:

  		max_blocks = min_not_zero(sdkp->max_ws_blocks,
  					  (u32)SD_MAX_WS10_BLOCKS);

  		q->limits.discard_zeroes_data = 1;
  		break;
  	}

  	blk_queue_max_discard_sectors(q, max_blocks * (logical_block_size >> 9));

  	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);

  }

  /**

   * sd_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 sd_setup_discard_cmnd(struct scsi_cmnd *cmd)

  {

  	struct request *rq = cmd->request;
  	struct scsi_device *sdp = cmd->device;

  	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);

  	sector_t sector = blk_rq_pos(rq);
  	unsigned int nr_sectors = blk_rq_sectors(rq);
  	unsigned int nr_bytes = blk_rq_bytes(rq);

  	unsigned int len;

  	int ret;

  	char *buf;

  	struct page *page;

  	sector >>= ilog2(sdp->sector_size) - 9;
  	nr_sectors >>= ilog2(sdp->sector_size) - 9;

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

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

  		cmd->cmd_len = 10;
  		cmd->cmnd[0] = UNMAP;
  		cmd->cmnd[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:

  		cmd->cmd_len = 16;
  		cmd->cmnd[0] = WRITE_SAME_16;
  		cmd->cmnd[1] = 0x8; /* UNMAP */
  		put_unaligned_be64(sector, &cmd->cmnd[2]);
  		put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);

  
  		len = sdkp->device->sector_size;

  		break;
  
  	case SD_LBP_WS10:
  	case SD_LBP_ZERO:

  		cmd->cmd_len = 10;
  		cmd->cmnd[0] = WRITE_SAME;

  		if (sdkp->provisioning_mode == SD_LBP_WS10)

  			cmd->cmnd[1] = 0x8; /* UNMAP */
  		put_unaligned_be32(sector, &cmd->cmnd[2]);
  		put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);

  
  		len = sdkp->device->sector_size;
  		break;
  
  	default:

  		ret = BLKPREP_INVALID;

  		goto out;

  	}

  	rq->completion_data = page;

  	rq->timeout = SD_TIMEOUT;
  
  	cmd->transfersize = len;

  	cmd->allowed = SD_MAX_RETRIES;

  
  	/*
  	 * Initially __data_len is set to the amount of data that needs to be
  	 * transferred to the target. This amount depends on whether WRITE SAME
  	 * or UNMAP is being used. After the scatterlist has been mapped by
  	 * scsi_init_io() we set __data_len to the size of the area to be
  	 * discarded on disk. This allows us to report completion on the full
  	 * amount of blocks described by the request.
  	 */

  	blk_add_request_payload(rq, page, len);

  	ret = scsi_init_io(cmd);

  	rq->__data_len = nr_bytes;

  
  out:

  	if (ret != BLKPREP_OK)

  		__free_page(page);

  	return ret;
  }

  static void sd_config_write_same(struct scsi_disk *sdkp)
  {
  	struct request_queue *q = sdkp->disk->queue;
  	unsigned int logical_block_size = sdkp->device->sector_size;

  
  	if (sdkp->device->no_write_same) {
  		sdkp->max_ws_blocks = 0;
  		goto out;
  	}
  
  	/* Some devices can not handle block counts above 0xffff despite
  	 * supporting WRITE SAME(16). Consequently we default to 64k
  	 * blocks per I/O unless the device explicitly advertises a
  	 * bigger limit.
  	 */

  	if (sdkp->max_ws_blocks > SD_MAX_WS10_BLOCKS)
  		sdkp->max_ws_blocks = min_not_zero(sdkp->max_ws_blocks,
  						   (u32)SD_MAX_WS16_BLOCKS);
  	else if (sdkp->ws16 || sdkp->ws10 || sdkp->device->no_report_opcodes)
  		sdkp->max_ws_blocks = min_not_zero(sdkp->max_ws_blocks,
  						   (u32)SD_MAX_WS10_BLOCKS);
  	else {
  		sdkp->device->no_write_same = 1;
  		sdkp->max_ws_blocks = 0;
  	}

  
  out:

  	blk_queue_max_write_same_sectors(q, sdkp->max_ws_blocks *
  					 (logical_block_size >> 9));

  }
  
  /**
   * sd_setup_write_same_cmnd - write the same data to multiple blocks

   * @cmd: command to prepare

   *
   * Will issue either WRITE SAME(10) or WRITE SAME(16) depending on
   * preference indicated by target device.
   **/

  static int sd_setup_write_same_cmnd(struct scsi_cmnd *cmd)

  {

  	struct request *rq = cmd->request;
  	struct scsi_device *sdp = cmd->device;

  	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
  	struct bio *bio = rq->bio;
  	sector_t sector = blk_rq_pos(rq);
  	unsigned int nr_sectors = blk_rq_sectors(rq);
  	unsigned int nr_bytes = blk_rq_bytes(rq);
  	int ret;
  
  	if (sdkp->device->no_write_same)

  		return BLKPREP_INVALID;

  	BUG_ON(bio_offset(bio) || bio_iovec(bio).bv_len != sdp->sector_size);

  
  	sector >>= ilog2(sdp->sector_size) - 9;
  	nr_sectors >>= ilog2(sdp->sector_size) - 9;

  	rq->timeout = SD_WRITE_SAME_TIMEOUT;

  
  	if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff) {

  		cmd->cmd_len = 16;
  		cmd->cmnd[0] = WRITE_SAME_16;
  		put_unaligned_be64(sector, &cmd->cmnd[2]);
  		put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);

  	} else {

  		cmd->cmd_len = 10;
  		cmd->cmnd[0] = WRITE_SAME;
  		put_unaligned_be32(sector, &cmd->cmnd[2]);
  		put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);

  	}

  	cmd->transfersize = sdp->sector_size;

  	cmd->allowed = SD_MAX_RETRIES;

  	/*
  	 * For WRITE_SAME the data transferred in the DATA IN buffer is
  	 * different from the amount of data actually written to the target.
  	 *
  	 * We set up __data_len to the amount of data transferred from the
  	 * DATA IN buffer so that blk_rq_map_sg set up the proper S/G list
  	 * to transfer a single sector of data first, but then reset it to
  	 * the amount of data to be written right after so that the I/O path
  	 * knows how much to actually write.
  	 */
  	rq->__data_len = sdp->sector_size;

  	ret = scsi_init_io(cmd);

  	rq->__data_len = nr_bytes;

  	return ret;
  }

  static int sd_setup_flush_cmnd(struct scsi_cmnd *cmd)

  {

  	struct request *rq = cmd->request;
  
  	/* flush requests don't perform I/O, zero the S/G table */
  	memset(&cmd->sdb, 0, sizeof(cmd->sdb));

  	cmd->cmnd[0] = SYNCHRONIZE_CACHE;
  	cmd->cmd_len = 10;
  	cmd->transfersize = 0;
  	cmd->allowed = SD_MAX_RETRIES;

  	rq->timeout = rq->q->rq_timeout * SD_FLUSH_TIMEOUT_MULTIPLIER;

  	return BLKPREP_OK;

  }

  static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)

  {

  	struct request *rq = SCpnt->request;
  	struct scsi_device *sdp = SCpnt->device;

  	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);

  	unsigned int dif, dix;
  	int ret;

  	unsigned char protect;

  	ret = scsi_init_io(SCpnt);

  	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,
  			"%s: block=%llu, count=%d
  ",
  			__func__, (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) {

  		SCpnt->cmnd[0] = WRITE_6;

  		if (blk_integrity_rq(rq))

  			sd_dif_prepare(SCpnt);

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

  	} else {

  		scmd_printk(KERN_ERR, SCpnt, "Unknown command %llx
  ", (unsigned long long) 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)));

  	dix = scsi_prot_sg_count(SCpnt);
  	dif = scsi_host_dif_capable(SCpnt->device->host, sdkp->protection_type);
  
  	if (dif || dix)
  		protect = sd_setup_protect_cmnd(SCpnt, dix, dif);

  	else

  		protect = 0;

  	if (protect && sdkp->protection_type == 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 (sdp->use_16_for_rw || (this_count > 0xffff)) {

  		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) {

  		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;

  
  	/*
  	 * 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 ret;

  }

  static int sd_init_command(struct scsi_cmnd *cmd)
  {
  	struct request *rq = cmd->request;
  
  	if (rq->cmd_flags & REQ_DISCARD)
  		return sd_setup_discard_cmnd(cmd);
  	else if (rq->cmd_flags & REQ_WRITE_SAME)
  		return sd_setup_write_same_cmnd(cmd);
  	else if (rq->cmd_flags & REQ_FLUSH)
  		return sd_setup_flush_cmnd(cmd);
  	else
  		return sd_setup_read_write_cmnd(cmd);
  }
  
  static void sd_uninit_command(struct scsi_cmnd *SCpnt)
  {
  	struct request *rq = SCpnt->request;
  
  	if (rq->cmd_flags & REQ_DISCARD)
  		__free_page(rq->completion_data);
  
  	if (SCpnt->cmnd != rq->cmd) {
  		mempool_free(SCpnt->cmnd, sd_cdb_pool);
  		SCpnt->cmnd = NULL;
  		SCpnt->cmd_len = 0;
  	}
  }

  /**
   *	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;
  
  	/*
  	 * 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_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 void 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_disk_put(sdkp);

  }

  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));

  	error = scsi_verify_blk_ioctl(bdev, cmd);
  	if (error < 0)
  		return error;

  	/*
  	 * 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_ioctl_block_when_processing_errors(sdp, cmd,
  			(mode & FMODE_NDELAY) != 0);
  	if (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_blk_ioctl(bdev, 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;

  	const int timeout = sdp->request_queue->rq_timeout
  		* SD_FLUSH_TIMEOUT_MULTIPLIER;

  	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_flags(sdp, cmd, DMA_NONE, NULL, 0,

  					     &sshdr, timeout, SD_MAX_RETRIES,
  					     NULL, REQ_PM);

  		if (res == 0)

  			break;
  	}

  	if (res) {

  		sd_print_result(sdkp, "Synchronize Cache(10) failed", res);

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

  		/* we need to evaluate the error return  */
  		if (scsi_sense_valid(&sshdr) &&

  			(sshdr.asc == 0x3a ||	/* medium not present */
  			 sshdr.asc == 0x20))	/* invalid command */

  				/* this is no error here */
  				return 0;
  
  		switch (host_byte(res)) {
  		/* ignore errors due to racing a disconnection */
  		case DID_BAD_TARGET:
  		case DID_NO_CONNECT:
  			return 0;
  		/* signal the upper layer it might try again */
  		case DID_BUS_BUSY:
  		case DID_IMM_RETRY:
  		case DID_REQUEUE:
  		case DID_SOFT_ERROR:
  			return -EBUSY;
  		default:
  			return -EIO;
  		}

  	}

  	return 0;

  }

  static void sd_rescan(struct device *dev)
  {

  	struct scsi_disk *sdkp = dev_get_drvdata(dev);

  	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 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;

  	int error;

  	error = scsi_ioctl_block_when_processing_errors(sdev, cmd,
  			(mode & FMODE_NDELAY) != 0);
  	if (error)
  		return error;

  	/* 
  	 * Let the static ioctl translation table take care of it.
  	 */

  	if (!sdev->host->hostt->compat_ioctl)
  		return -ENOIOCTLCMD; 
  	return sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);

  }
  #endif

  static char sd_pr_type(enum pr_type type)
  {
  	switch (type) {
  	case PR_WRITE_EXCLUSIVE:
  		return 0x01;
  	case PR_EXCLUSIVE_ACCESS:
  		return 0x03;
  	case PR_WRITE_EXCLUSIVE_REG_ONLY:
  		return 0x05;
  	case PR_EXCLUSIVE_ACCESS_REG_ONLY:
  		return 0x06;
  	case PR_WRITE_EXCLUSIVE_ALL_REGS:
  		return 0x07;
  	case PR_EXCLUSIVE_ACCESS_ALL_REGS:
  		return 0x08;
  	default:
  		return 0;
  	}
  };
  
  static int sd_pr_command(struct block_device *bdev, u8 sa,
  		u64 key, u64 sa_key, u8 type, u8 flags)
  {
  	struct scsi_device *sdev = scsi_disk(bdev->bd_disk)->device;
  	struct scsi_sense_hdr sshdr;
  	int result;
  	u8 cmd[16] = { 0, };
  	u8 data[24] = { 0, };
  
  	cmd[0] = PERSISTENT_RESERVE_OUT;
  	cmd[1] = sa;
  	cmd[2] = type;
  	put_unaligned_be32(sizeof(data), &cmd[5]);
  
  	put_unaligned_be64(key, &data[0]);
  	put_unaligned_be64(sa_key, &data[8]);
  	data[20] = flags;
  
  	result = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, &data, sizeof(data),
  			&sshdr, SD_TIMEOUT, SD_MAX_RETRIES, NULL);
  
  	if ((driver_byte(result) & DRIVER_SENSE) &&
  	    (scsi_sense_valid(&sshdr))) {
  		sdev_printk(KERN_INFO, sdev, "PR command failed: %d
  ", result);
  		scsi_print_sense_hdr(sdev, NULL, &sshdr);
  	}
  
  	return result;
  }
  
  static int sd_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
  		u32 flags)
  {
  	if (flags & ~PR_FL_IGNORE_KEY)
  		return -EOPNOTSUPP;
  	return sd_pr_command(bdev, (flags & PR_FL_IGNORE_KEY) ? 0x06 : 0x00,
  			old_key, new_key, 0,
  			(1 << 0) /* APTPL */ |
  			(1 << 2) /* ALL_TG_PT */);
  }
  
  static int sd_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
  		u32 flags)
  {
  	if (flags)
  		return -EOPNOTSUPP;
  	return sd_pr_command(bdev, 0x01, key, 0, sd_pr_type(type), 0);
  }
  
  static int sd_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
  {
  	return sd_pr_command(bdev, 0x02, key, 0, sd_pr_type(type), 0);
  }
  
  static int sd_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
  		enum pr_type type, bool abort)
  {
  	return sd_pr_command(bdev, abort ? 0x05 : 0x04, old_key, new_key,
  			     sd_pr_type(type), 0);
  }
  
  static int sd_pr_clear(struct block_device *bdev, u64 key)
  {
  	return sd_pr_command(bdev, 0x03, key, 0, 0, 0);
  }
  
  static const struct pr_ops sd_pr_ops = {
  	.pr_register	= sd_pr_register,
  	.pr_reserve	= sd_pr_reserve,
  	.pr_release	= sd_pr_release,
  	.pr_preempt	= sd_pr_preempt,
  	.pr_clear	= sd_pr_clear,
  };

  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,

  	.pr_ops			= &sd_pr_ops,

  };

  /**
   *	sd_eh_action - error handling callback
   *	@scmd:		sd-issued command that has failed

   *	@eh_disp:	The recovery disposition suggested by the midlayer
   *

   *	This function is called by the SCSI midlayer upon completion of an
   *	error test command (currently TEST UNIT READY). The result of sending
   *	the eh command is passed in eh_disp.  We're looking for devices that
   *	fail medium access commands but are OK with non access commands like
   *	test unit ready (so wrongly see the device as having a successful
   *	recovery)

   **/

  static int sd_eh_action(struct scsi_cmnd *scmd, int eh_disp)

  {
  	struct scsi_disk *sdkp = scsi_disk(scmd->request->rq_disk);
  
  	if (!scsi_device_online(scmd->device) ||

  	    !scsi_medium_access_command(scmd) ||
  	    host_byte(scmd->result) != DID_TIME_OUT ||
  	    eh_disp != SUCCESS)

  		return eh_disp;
  
  	/*
  	 * The device has timed out executing a medium access command.
  	 * However, the TEST UNIT READY command sent during error
  	 * handling completed successfully. Either the device is in the
  	 * process of recovering or has it suffered an internal failure
  	 * that prevents access to the storage medium.
  	 */

  	sdkp->medium_access_timed_out++;

  
  	/*
  	 * If the device keeps failing read/write commands but TEST UNIT
  	 * READY always completes successfully we assume that medium
  	 * access is no longer possible and take the device offline.
  	 */
  	if (sdkp->medium_access_timed_out >= sdkp->max_medium_access_timeouts) {
  		scmd_printk(KERN_ERR, scmd,
  			    "Medium access timeout failure. Offlining disk!
  ");
  		scsi_device_set_state(scmd->device, SDEV_OFFLINE);
  
  		return FAILED;
  	}
  
  	return eh_disp;
  }

  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 factor = scmd->device->sector_size / 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;

  	/* be careful ... don't want any overflows */
  	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);

  	struct request *req = SCpnt->request;

  	int sense_valid = 0;
  	int sense_deferred = 0;

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

  	unsigned char unmap = SCpnt->cmnd[1] & 8;

  	if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME) {

  		if (!result) {
  			good_bytes = blk_rq_bytes(req);
  			scsi_set_resid(SCpnt, 0);
  		} else {
  			good_bytes = 0;
  			scsi_set_resid(SCpnt, blk_rq_bytes(req));
  		}
  	}

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

  	sdkp->medium_access_timed_out = 0;

  	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.
  		 */

  		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) {
  			switch (op) {
  			case UNMAP:
  				sd_config_discard(sdkp, SD_LBP_DISABLE);
  				break;
  			case WRITE_SAME_16:
  			case WRITE_SAME:
  				if (unmap)
  					sd_config_discard(sdkp, SD_LBP_DISABLE);
  				else {
  					sdkp->device->no_write_same = 1;
  					sd_config_write_same(sdkp);
  
  					good_bytes = 0;
  					req->__data_len = blk_rq_bytes(req);
  					req->cmd_flags |= REQ_QUIET;
  				}
  			}
  		}

  		break;
  	default:
  		break;

  	}

   out:

  	SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
  					   "sd_done: completed %d of %d bytes
  ",
  					   good_bytes, scsi_bufflen(SCpnt)));

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

  	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_print_result(sdkp, "Test Unit Ready failed",
  						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 int sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)

  {
  	struct scsi_device *sdp = sdkp->device;
  	u8 type;

  	int ret = 0;

  
  	if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)

  		return ret;

  
  	type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */

  	if (type > SD_DIF_TYPE3_PROTECTION)
  		ret = -ENODEV;
  	else if (scsi_host_dif_capable(sdp->host, type))
  		ret = 1;
  
  	if (sdkp->first_scan || type != sdkp->protection_type)
  		switch (ret) {
  		case -ENODEV:
  			sd_printk(KERN_ERR, sdkp, "formatted with unsupported" \
  				  " protection type %u. Disabling disk!
  ",
  				  type);
  			break;
  		case 1:
  			sd_printk(KERN_NOTICE, sdkp,
  				  "Enabling DIF Type %u protection
  ", type);
  			break;
  		case 0:
  			sd_printk(KERN_NOTICE, sdkp,
  				  "Disabling DIF Type %u protection
  ", type);
  			break;
  		}

  	sdkp->protection_type = type;

  	return ret;

  }

  static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
  			struct scsi_sense_hdr *sshdr, int sense_valid,
  			int 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 {