Revision 3e1a0699095803e53072699a4a1485af7744601d authored by Joe Thornber on 03 March 2014, 16:03:26 UTC, committed by Mike Snitzer on 05 March 2014, 20:26:58 UTC
Ideally a thin pool would never run out of data space; the low water
mark would trigger userland to extend the pool before we completely run
out of space.  However, many small random IOs to unprovisioned space can
consume data space at an alarming rate.  Adjust your low water mark if
you're frequently seeing "out-of-data-space" mode.

Before this fix, if data space ran out the pool would be put in
PM_READ_ONLY mode which also aborted the pool's current metadata
transaction (data loss for any changes in the transaction).  This had a
side-effect of needlessly compromising data consistency.  And retry of
queued unserviceable bios, once the data pool was resized, could
initiate changes to potentially inconsistent pool metadata.

Now when the pool's data space is exhausted transition to a new pool
mode (PM_OUT_OF_DATA_SPACE) that allows metadata to be changed but data
may not be allocated.  This allows users to remove thin volumes or
discard data to recover data space.

The pool is no longer put in PM_READ_ONLY mode in response to the pool
running out of data space.  And PM_READ_ONLY mode no longer aborts the
pool's current metadata transaction.  Also, set_pool_mode() will now
notify userspace when the pool mode is changed.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 parent 07f2b6e
Raw File
sd.c
/*
 *      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_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_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(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
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] == '\n') {
			ct = i;
			break;
		}
	}
	if (ct < 0)
		return -EINVAL;
	rcd = ct & 0x01 ? 1 : 0;
	wce = ct & 0x02 ? 1 : 0;

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

	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\n", 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\n", 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\n", 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\n", 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\n", 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\n");

	return snprintf(buf, 20, "%s%u\n", 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\n", 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\n", 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\n", 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\n", 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\n", 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 = {
	.owner			= THIS_MODULE,
	.gendrv = {
		.name		= "sd",
		.probe		= sd_probe,
		.remove		= sd_remove,
		.shutdown	= sd_shutdown,
		.pm		= &sd_pm_ops,
	},
	.rescan			= sd_rescan,
	.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;

	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);

	sdkp->provisioning_mode = mode;

	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,
					  (u32)SD_MAX_WS16_BLOCKS);
		break;

	case SD_LBP_WS16:
		max_blocks = min_not_zero(sdkp->max_ws_blocks,
					  (u32)SD_MAX_WS16_BLOCKS);
		break;

	case SD_LBP_WS10:
		max_blocks = min_not_zero(sdkp->max_ws_blocks,
					  (u32)SD_MAX_WS10_BLOCKS);
		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;
	}

	q->limits.max_discard_sectors = 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_device *sdp, struct request *rq)
{
	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;
	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);
	rq->__data_len = nr_bytes;

out:
	if (ret != BLKPREP_OK) {
		__free_page(page);
		rq->buffer = NULL;
	}
	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
 * @sdp: scsi device to operate one
 * @rq: Request 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_device *sdp, struct request *rq)
{
	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_KILL;

	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->__data_len = sdp->sector_size;
	rq->timeout = SD_WRITE_SAME_TIMEOUT;
	memset(rq->cmd, 0, rq->cmd_len);

	if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff) {
		rq->cmd_len = 16;
		rq->cmd[0] = WRITE_SAME_16;
		put_unaligned_be64(sector, &rq->cmd[2]);
		put_unaligned_be32(nr_sectors, &rq->cmd[10]);
	} else {
		rq->cmd_len = 10;
		rq->cmd[0] = WRITE_SAME;
		put_unaligned_be32(sector, &rq->cmd[2]);
		put_unaligned_be16(nr_sectors, &rq->cmd[7]);
	}

	ret = scsi_setup_blk_pc_cmnd(sdp, rq);
	rq->__data_len = nr_bytes;

	return ret;
}

static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
{
	rq->timeout *= SD_FLUSH_TIMEOUT_MULTIPLIER;
	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)
{
	struct scsi_cmnd *SCpnt = rq->special;

	if (rq->cmd_flags & REQ_DISCARD) {
		free_page((unsigned long)rq->buffer);
		rq->buffer = NULL;
	}
	if (SCpnt->cmnd != rq->cmd) {
		mempool_free(SCpnt->cmnd, sd_cdb_pool);
		SCpnt->cmnd = NULL;
		SCpnt->cmd_len = 0;
	}
}

/**
 *	sd_prep_fn - 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 = sd_setup_discard_cmnd(sdp, rq);
		goto out;
	} else if (rq->cmd_flags & REQ_WRITE_SAME) {
		ret = sd_setup_write_same_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_prep_fn: block=%llu, "
					"count=%d\n",
					(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\n",
						blk_rq_sectors(rq)));
		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
						"Retry with 0x%p\n", 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.\n"); */
		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\n",
					(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\n");
			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\n");
			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\n");
			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);

	} 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 %llx\n", (unsigned long long) rq->cmd_flags);
		goto out;
	}

	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
					"%s %d/%u 512 byte blocks.\n",
					(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 (sdp->use_16_for_rw) {
		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\n");
			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\n"));

	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\n"));

	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\n", 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_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_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\n"));

	/*
	 * 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, 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) &&
			/* 0x3a is medium not present */
			sshdr.asc == 0x3a)
				/* 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 = 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;
	int ret;

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

	/*
	 * 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) {
		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,
};

/**
 *	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!\n");
		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 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 */
		unsigned int 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);
	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);
	}
#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\n",
						   sshdr.response_code,
						   sshdr.sense_key, sshdr.asc,
						   sshdr.ascq));
	}
#endif
	if (driver_byte(result) != DRIVER_SENSE &&
	    (!sense_valid || sense_deferred))
		goto out;

	sdkp->medium_access_timed_out = 0;

	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) {
			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:
	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_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
				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\n");
				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\n");
		else
			printk("not responding...\n");
	}
}


/*
 * 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!\n",
				  type);
			break;
		case 1:
			sd_printk(KERN_NOTICE, sdkp,
				  "Enabling DIF Type %u protection\n", type);
			break;
		case 0:
			sd_printk(KERN_NOTICE, sdkp,
				  "Disabling DIF Type %u protection\n", 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)
{
	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.\n");

	/*
	 * 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\n");
		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]);

	if (sd_read_protection_type(sdkp, buffer) < 0) {
		sdkp->capacity = 0;
		return -ENODEV;
	}

	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.\n");
		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\n", 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\n");
		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.\n");
		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->try_rc_10_first)
		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).\n");
			sector_size = read_capacity_16(sdkp, sdp, buffer);
			if (sector_size < 0) {
				sd_printk(KERN_NOTICE, sdkp,
					"Using 0xffffffff as device size\n");
				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\n",
				(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.\n");
	}

	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.\n",
			  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)\n",
				  (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\n",
					  sdkp->physical_block_size);
		}
	}

	sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);

	/* 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\n");
		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\n");
	} 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\n",
				  sdkp->write_prot ? "on" : "off");
			sd_printk(KERN_DEBUG, sdkp,
				  "Mode Sense: %02x %02x %02x %02x\n",
				  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;


	if (sdkp->cache_override)
		return;

	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\n");
	}

	/* 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\n", 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\n");
					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\n");
					goto defaults;
				}
			}
		}

		sd_printk(KERN_ERR, sdkp, "No Caching mode page found\n");
		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\n");
			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\n",
				  sdkp->WCE ? "enabled" : "disabled",
				  sdkp->RCD ? "disabled" : "enabled",
				  sdkp->DPOFUA ? "supports DPO and FUA"
				  : "doesn't support DPO or FUA");

		return;
	}

bad_sense:
	if (scsi_sense_valid(&sshdr) &&
	    sshdr.sense_key == ILLEGAL_REQUEST &&
	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
		/* Invalid field in CDB */
		sd_printk(KERN_NOTICE, sdkp, "Cache data unavailable\n");
	else
		sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n");

defaults:
	if (sdp->wce_default_on) {
		sd_printk(KERN_NOTICE, sdkp, "Assuming drive cache: write back\n");
		sdkp->WCE = 1;
	} else {
		sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
		sdkp->WCE = 0;
	}
	sdkp->RCD = 0;
	sdkp->DPOFUA = 0;
}

/*
 * The ATO bit indicates whether the DIF application tag is available
 * for use by the operating system.
 */
static void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
{
	int res, offset;
	struct scsi_device *sdp = sdkp->device;
	struct scsi_mode_data data;
	struct scsi_sense_hdr sshdr;

	if (sdp->type != TYPE_DISK)
		return;

	if (sdkp->protection_type == 0)
		return;

	res = scsi_mode_sense(sdp, 1, 0x0a, buffer, 36, SD_TIMEOUT,
			      SD_MAX_RETRIES, &data, &sshdr);

	if (!scsi_status_is_good(res) || !data.header_length ||
	    data.length < 6) {
		sd_printk(KERN_WARNING, sdkp,
			  "getting Control mode page failed, assume no ATO\n");

		if (scsi_sense_valid(&sshdr))
			sd_print_sense_hdr(sdkp, &sshdr);

		return;
	}

	offset = data.header_length + data.block_descriptor_length;

	if ((buffer[offset] & 0x3f) != 0x0a) {
		sd_printk(KERN_ERR, sdkp, "ATO Got wrong page\n");
		return;
	}

	if ((buffer[offset + 5] & 0x80) == 0)
		return;

	sdkp->ATO = 1;

	return;
}

/**
 * sd_read_block_limits - Query disk device for preferred I/O sizes.
 * @disk: disk to query
 */
static void sd_read_block_limits(struct scsi_disk *sdkp)
{
	unsigned int sector_sz = sdkp->device->sector_size;
	const int vpd_len = 64;
	unsigned char *buffer = kmalloc(vpd_len, GFP_KERNEL);

	if (!buffer ||
	    /* Block Limits VPD */
	    scsi_get_vpd_page(sdkp->device, 0xb0, buffer, vpd_len))
		goto out;

	blk_queue_io_min(sdkp->disk->queue,
			 get_unaligned_be16(&buffer[6]) * sector_sz);
	blk_queue_io_opt(sdkp->disk->queue,
			 get_unaligned_be32(&buffer[12]) * sector_sz);

	if (buffer[3] == 0x3c) {
		unsigned int lba_count, desc_count;

		sdkp->max_ws_blocks = (u32)get_unaligned_be64(&buffer[36]);

		if (!sdkp->lbpme)
			goto out;

		lba_count = get_unaligned_be32(&buffer[20]);
		desc_count = get_unaligned_be32(&buffer[24]);

		if (lba_count && desc_count)
			sdkp->max_unmap_blocks = lba_count;

		sdkp->unmap_granularity = get_unaligned_be32(&buffer[28]);

		if (buffer[32] & 0x80)
			sdkp->unmap_alignment =
				get_unaligned_be32(&buffer[32]) & ~(1 << 31);

		if (!sdkp->lbpvpd) { /* LBP VPD page not provided */

			if (sdkp->max_unmap_blocks)
				sd_config_discard(sdkp, SD_LBP_UNMAP);
			else
				sd_config_discard(sdkp, SD_LBP_WS16);

		} else {	/* LBP VPD page tells us what to use */

			if (sdkp->lbpu && sdkp->max_unmap_blocks)
				sd_config_discard(sdkp, SD_LBP_UNMAP);
			else if (sdkp->lbpws)
				sd_config_discard(sdkp, SD_LBP_WS16);
			else if (sdkp->lbpws10)
				sd_config_discard(sdkp, SD_LBP_WS10);
			else
				sd_config_discard(sdkp, SD_LBP_DISABLE);
		}
	}

 out:
	kfree(buffer);
}

/**
 * sd_read_block_characteristics - Query block dev. characteristics
 * @disk: disk to query
 */
static void sd_read_block_characteristics(struct scsi_disk *sdkp)
{
	unsigned char *buffer;
	u16 rot;
	const int vpd_len = 64;

	buffer = kmalloc(vpd_len, GFP_KERNEL);

	if (!buffer ||
	    /* Block Device Characteristics VPD */
	    scsi_get_vpd_page(sdkp->device, 0xb1, buffer, vpd_len))
		goto out;

	rot = get_unaligned_be16(&buffer[4]);

	if (rot == 1)
		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, sdkp->disk->queue);

 out:
	kfree(buffer);
}

/**
 * sd_read_block_provisioning - Query provisioning VPD page
 * @disk: disk to query
 */
static void sd_read_block_provisioning(struct scsi_disk *sdkp)
{
	unsigned char *buffer;
	const int vpd_len = 8;

	if (sdkp->lbpme == 0)
		return;

	buffer = kmalloc(vpd_len, GFP_KERNEL);

	if (!buffer || scsi_get_vpd_page(sdkp->device, 0xb2, buffer, vpd_len))
		goto out;

	sdkp->lbpvpd	= 1;
	sdkp->lbpu	= (buffer[5] >> 7) & 1;	/* UNMAP */
	sdkp->lbpws	= (buffer[5] >> 6) & 1;	/* WRITE SAME(16) with UNMAP */
	sdkp->lbpws10	= (buffer[5] >> 5) & 1;	/* WRITE SAME(10) with UNMAP */

 out:
	kfree(buffer);
}

static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
{
	struct scsi_device *sdev = sdkp->device;

	if (sdev->host->no_write_same) {
		sdev->no_write_same = 1;

		return;
	}

	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, INQUIRY) < 0) {
		/* too large values might cause issues with arcmsr */
		int vpd_buf_len = 64;

		sdev->no_report_opcodes = 1;

		/* Disable WRITE SAME if REPORT SUPPORTED OPERATION
		 * CODES is unsupported and the device has an ATA
		 * Information VPD page (SAT).
		 */
		if (!scsi_get_vpd_page(sdev, 0x89, buffer, vpd_buf_len))
			sdev->no_write_same = 1;
	}

	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME_16) == 1)
		sdkp->ws16 = 1;

	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME) == 1)
		sdkp->ws10 = 1;
}

static int sd_try_extended_inquiry(struct scsi_device *sdp)
{
	/*
	 * Although VPD inquiries can go to SCSI-2 type devices,
	 * some USB ones crash on receiving them, and the pages
	 * we currently ask for are for SPC-3 and beyond
	 */
	if (sdp->scsi_level > SCSI_SPC_2 && !sdp->skip_vpd_pages)
		return 1;
	return 0;
}

/**
 *	sd_revalidate_disk - called the first time a new disk is seen,
 *	performs disk spin up, read_capacity, etc.
 *	@disk: struct gendisk we care about
 **/
static int sd_revalidate_disk(struct gendisk *disk)
{
	struct scsi_disk *sdkp = scsi_disk(disk);
	struct scsi_device *sdp = sdkp->device;
	unsigned char *buffer;
	unsigned flush = 0;

	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
				      "sd_revalidate_disk\n"));

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

	buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL);
	if (!buffer) {
		sd_printk(KERN_WARNING, sdkp, "sd_revalidate_disk: Memory "
			  "allocation failure.\n");
		goto out;
	}

	sd_spinup_disk(sdkp);

	/*
	 * Without media there is no reason to ask; moreover, some devices
	 * react badly if we do.
	 */
	if (sdkp->media_present) {
		sd_read_capacity(sdkp, buffer);

		if (sd_try_extended_inquiry(sdp)) {
			sd_read_block_provisioning(sdkp);
			sd_read_block_limits(sdkp);
			sd_read_block_characteristics(sdkp);
		}

		sd_read_write_protect_flag(sdkp, buffer);
		sd_read_cache_type(sdkp, buffer);
		sd_read_app_tag_own(sdkp, buffer);
		sd_read_write_same(sdkp, buffer);
	}

	sdkp->first_scan = 0;

	/*
	 * We now have all cache related info, determine how we deal
	 * with flush requests.
	 */
	if (sdkp->WCE) {
		flush |= REQ_FLUSH;
		if (sdkp->DPOFUA)
			flush |= REQ_FUA;
	}

	blk_queue_flush(sdkp->disk->queue, flush);

	set_capacity(disk, sdkp->capacity);
	sd_config_write_same(sdkp);
	kfree(buffer);

 out:
	return 0;
}

/**
 *	sd_unlock_native_capacity - unlock native capacity
 *	@disk: struct gendisk to set capacity for
 *
 *	Block layer calls this function if it detects that partitions
 *	on @disk reach beyond the end of the device.  If the SCSI host
 *	implements ->unlock_native_capacity() method, it's invoked to
 *	give it a chance to adjust the device capacity.
 *
 *	CONTEXT:
 *	Defined by block layer.  Might sleep.
 */
static void sd_unlock_native_capacity(struct gendisk *disk)
{
	struct scsi_device *sdev = scsi_disk(disk)->device;

	if (sdev->host->hostt->unlock_native_capacity)
		sdev->host->hostt->unlock_native_capacity(sdev);
}

/**
 *	sd_format_disk_name - format disk name
 *	@prefix: name prefix - ie. "sd" for SCSI disks
 *	@index: index of the disk to format name for
 *	@buf: output buffer
 *	@buflen: length of the output buffer
 *
 *	SCSI disk names starts at sda.  The 26th device is sdz and the
 *	27th is sdaa.  The last one for two lettered suffix is sdzz
 *	which is followed by sdaaa.
 *
 *	This is basically 26 base counting with one extra 'nil' entry
 *	at the beginning from the second digit on and can be
 *	determined using similar method as 26 base conversion with the
 *	index shifted -1 after each digit is computed.
 *
 *	CONTEXT:
 *	Don't care.
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int sd_format_disk_name(char *prefix, int index, char *buf, int buflen)
{
	const int base = 'z' - 'a' + 1;
	char *begin = buf + strlen(prefix);
	char *end = buf + buflen;
	char *p;
	int unit;

	p = end - 1;
	*p = '\0';
	unit = base;
	do {
		if (p == begin)
			return -EINVAL;
		*--p = 'a' + (index % unit);
		index = (index / unit) - 1;
	} while (index >= 0);

	memmove(begin, p, end - p);
	memcpy(buf, prefix, strlen(prefix));

	return 0;
}

/*
 * The asynchronous part of sd_probe
 */
static void sd_probe_async(void *data, async_cookie_t cookie)
{
	struct scsi_disk *sdkp = data;
	struct scsi_device *sdp;
	struct gendisk *gd;
	u32 index;
	struct device *dev;

	sdp = sdkp->device;
	gd = sdkp->disk;
	index = sdkp->index;
	dev = &sdp->sdev_gendev;

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

	gd->fops = &sd_fops;
	gd->private_data = &sdkp->driver;
	gd->queue = sdkp->device->request_queue;

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

	sd_revalidate_disk(gd);

	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
	blk_queue_unprep_rq(sdp->request_queue, sd_unprep_fn);

	gd->driverfs_dev = &sdp->sdev_gendev;
	gd->flags = GENHD_FL_EXT_DEVT;
	if (sdp->removable) {
		gd->flags |= GENHD_FL_REMOVABLE;
		gd->events |= DISK_EVENT_MEDIA_CHANGE;
	}

	blk_pm_runtime_init(sdp->request_queue, dev);
	add_disk(gd);
	if (sdkp->capacity)
		sd_dif_config_host(sdkp);

	sd_revalidate_disk(gd);

	sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
		  sdp->removable ? "removable " : "");
	scsi_autopm_put_device(sdp);
	put_device(&sdkp->dev);
}

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

	error = -ENODEV;
	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
		goto out;

	SCSI_LOG_HLQUEUE(3, sdev_printk(KERN_INFO, sdp,
					"sd_probe\n"));

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

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

	do {
		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
			goto out_put;

		spin_lock(&sd_index_lock);
		error = ida_get_new(&sd_index_ida, &index);
		spin_unlock(&sd_index_lock);
	} while (error == -EAGAIN);

	if (error) {
		sdev_printk(KERN_WARNING, sdp, "sd_probe: memory exhausted.\n");
		goto out_put;
	}

	error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN);
	if (error) {
		sdev_printk(KERN_WARNING, sdp, "SCSI disk (sd) name length exceeded.\n");
		goto out_free_index;
	}

	sdkp->device = sdp;
	sdkp->driver = &sd_template;
	sdkp->disk = gd;
	sdkp->index = index;
	atomic_set(&sdkp->openers, 0);
	atomic_set(&sdkp->device->ioerr_cnt, 0);

	if (!sdp->request_queue->rq_timeout) {
		if (sdp->type != TYPE_MOD)
			blk_queue_rq_timeout(sdp->request_queue, SD_TIMEOUT);
		else
			blk_queue_rq_timeout(sdp->request_queue,
					     SD_MOD_TIMEOUT);
	}

	device_initialize(&sdkp->dev);
	sdkp->dev.parent = dev;
	sdkp->dev.class = &sd_disk_class;
	dev_set_name(&sdkp->dev, "%s", dev_name(dev));

	if (device_add(&sdkp->dev))
		goto out_free_index;

	get_device(dev);
	dev_set_drvdata(dev, sdkp);

	get_device(&sdkp->dev);	/* prevent release before async_schedule */
	async_schedule_domain(sd_probe_async, sdkp, &scsi_sd_probe_domain);

	return 0;

 out_free_index:
	spin_lock(&sd_index_lock);
	ida_remove(&sd_index_ida, index);
	spin_unlock(&sd_index_lock);
 out_put:
	put_disk(gd);
 out_free:
	kfree(sdkp);
 out:
	return error;
}

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

	sdkp = dev_get_drvdata(dev);
	devt = disk_devt(sdkp->disk);
	scsi_autopm_get_device(sdkp->device);

	async_synchronize_full_domain(&scsi_sd_probe_domain);
	blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn);
	blk_queue_unprep_rq(sdkp->device->request_queue, NULL);
	device_del(&sdkp->dev);
	del_gendisk(sdkp->disk);
	sd_shutdown(dev);

	blk_register_region(devt, SD_MINORS, NULL,
			    sd_default_probe, NULL, NULL);

	mutex_lock(&sd_ref_mutex);
	dev_set_drvdata(dev, NULL);
	put_device(&sdkp->dev);
	mutex_unlock(&sd_ref_mutex);

	return 0;
}

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

	disk->private_data = NULL;
	put_disk(disk);
	put_device(&sdkp->device->sdev_gendev);

	kfree(sdkp);
}

static int sd_start_stop_device(struct scsi_disk *sdkp, int start)
{
	unsigned char cmd[6] = { START_STOP };	/* START_VALID */
	struct scsi_sense_hdr sshdr;
	struct scsi_device *sdp = sdkp->device;
	int res;

	if (start)
		cmd[4] |= 1;	/* START */

	if (sdp->start_stop_pwr_cond)
		cmd[4] |= start ? 1 << 4 : 3 << 4;	/* Active or Standby */

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

	res = scsi_execute_req_flags(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
			       SD_TIMEOUT, SD_MAX_RETRIES, NULL, REQ_PM);
	if (res) {
		sd_printk(KERN_WARNING, sdkp, "START_STOP FAILED\n");
		sd_print_result(sdkp, res);
		if (driver_byte(res) & DRIVER_SENSE)
			sd_print_sense_hdr(sdkp, &sshdr);
		if (scsi_sense_valid(&sshdr) &&
			/* 0x3a is medium not present */
			sshdr.asc == 0x3a)
			res = 0;
	}

	/* SCSI error codes must not go to the generic layer */
	if (res)
		return -EIO;

	return 0;
}

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

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

	if (pm_runtime_suspended(dev))
		goto exit;

	if (sdkp->WCE && sdkp->media_present) {
		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
		sd_sync_cache(sdkp);
	}

	if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
		sd_start_stop_device(sdkp, 0);
	}

exit:
	scsi_disk_put(sdkp);
}

static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
{
	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
	int ret = 0;

	if (!sdkp)
		return 0;	/* this can happen */

	if (sdkp->WCE && sdkp->media_present) {
		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
		ret = sd_sync_cache(sdkp);
		if (ret) {
			/* ignore OFFLINE device */
			if (ret == -ENODEV)
				ret = 0;
			goto done;
		}
	}

	if (sdkp->device->manage_start_stop) {
		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
		/* an error is not worth aborting a system sleep */
		ret = sd_start_stop_device(sdkp, 0);
		if (ignore_stop_errors)
			ret = 0;
	}

done:
	scsi_disk_put(sdkp);
	return ret;
}

static int sd_suspend_system(struct device *dev)
{
	return sd_suspend_common(dev, true);
}

static int sd_suspend_runtime(struct device *dev)
{
	return sd_suspend_common(dev, false);
}

static int sd_resume(struct device *dev)
{
	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
	int ret = 0;

	if (!sdkp->device->manage_start_stop)
		goto done;

	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
	ret = sd_start_stop_device(sdkp, 1);

done:
	scsi_disk_put(sdkp);
	return ret;
}

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

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

	for (i = 0; i < SD_MAJORS; i++) {
		if (register_blkdev(sd_major(i), "sd") != 0)
			continue;
		majors++;
		blk_register_region(sd_major(i), SD_MINORS, NULL,
				    sd_default_probe, NULL, NULL);
	}

	if (!majors)
		return -ENODEV;

	err = class_register(&sd_disk_class);
	if (err)
		goto err_out;

	sd_cdb_cache = kmem_cache_create("sd_ext_cdb", SD_EXT_CDB_SIZE,
					 0, 0, NULL);
	if (!sd_cdb_cache) {
		printk(KERN_ERR "sd: can't init extended cdb cache\n");
		goto err_out_class;
	}

	sd_cdb_pool = mempool_create_slab_pool(SD_MEMPOOL_SIZE, sd_cdb_cache);
	if (!sd_cdb_pool) {
		printk(KERN_ERR "sd: can't init extended cdb pool\n");
		goto err_out_cache;
	}

	err = scsi_register_driver(&sd_template.gendrv);
	if (err)
		goto err_out_driver;

	return 0;

err_out_driver:
	mempool_destroy(sd_cdb_pool);

err_out_cache:
	kmem_cache_destroy(sd_cdb_cache);

err_out_class:
	class_unregister(&sd_disk_class);
err_out:
	for (i = 0; i < SD_MAJORS; i++)
		unregister_blkdev(sd_major(i), "sd");
	return err;
}

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

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

	scsi_unregister_driver(&sd_template.gendrv);
	mempool_destroy(sd_cdb_pool);
	kmem_cache_destroy(sd_cdb_cache);

	class_unregister(&sd_disk_class);

	for (i = 0; i < SD_MAJORS; i++) {
		blk_unregister_region(sd_major(i), SD_MINORS);
		unregister_blkdev(sd_major(i), "sd");
	}
}

module_init(init_sd);
module_exit(exit_sd);

static void sd_print_sense_hdr(struct scsi_disk *sdkp,
			       struct scsi_sense_hdr *sshdr)
{
	sd_printk(KERN_INFO, sdkp, " ");
	scsi_show_sense_hdr(sshdr);
	sd_printk(KERN_INFO, sdkp, " ");
	scsi_show_extd_sense(sshdr->asc, sshdr->ascq);
}

static void sd_print_result(struct scsi_disk *sdkp, int result)
{
	sd_printk(KERN_INFO, sdkp, " ");
	scsi_show_result(result);
}

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