/*
 * vvvvvvvvvvvvvvvvvvvvvvv Original vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
 *  Copyright (C) 1992  Eric Youngdale
 *  Simulate a host adapter with 2 disks attached.  Do a lot of checking
 *  to make sure that we are not getting blocks mixed up, and PANIC if
 *  anything out of the ordinary is seen.
 * ^^^^^^^^^^^^^^^^^^^^^^^ Original ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 *
 *  This version is more generic, simulating a variable number of disk
 *  (or disk like devices) sharing a common amount of RAM. To be more
 *  realistic, the simulated devices have the transport attributes of
 *  SAS disks.
 *
 *
 *  For documentation see http://sg.danny.cz/sg/sdebug26.html
 *
 *   D. Gilbert (dpg) work for Magneto-Optical device test [20010421]
 *   dpg: work for devfs large number of disks [20010809]
 *        forked for lk 2.5 series [20011216, 20020101]
 *        use vmalloc() more inquiry+mode_sense [20020302]
 *        add timers for delayed responses [20020721]
 *   Patrick Mansfield <patmans@us.ibm.com> max_luns+scsi_level [20021031]
 *   Mike Anderson <andmike@us.ibm.com> sysfs work [20021118]
 *   dpg: change style of boot options to "scsi_debug.num_tgts=2" and
 *        module options to "modprobe scsi_debug num_tgts=2" [20021221]
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/genhd.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>
#include <linux/scatterlist.h>
#include <linux/blkdev.h>
#include <linux/crc-t10dif.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/atomic.h>
#include <linux/hrtimer.h>

#include <net/checksum.h>

#include <asm/unaligned.h>

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

#include "sd.h"
#include "scsi_logging.h"

#define SCSI_DEBUG_VERSION "1.84"
static const char *scsi_debug_version_date = "20140706";

#define MY_NAME "scsi_debug"

/* Additional Sense Code (ASC) */
#define NO_ADDITIONAL_SENSE 0x0
#define LOGICAL_UNIT_NOT_READY 0x4
#define LOGICAL_UNIT_COMMUNICATION_FAILURE 0x8
#define UNRECOVERED_READ_ERR 0x11
#define PARAMETER_LIST_LENGTH_ERR 0x1a
#define INVALID_OPCODE 0x20
#define ADDR_OUT_OF_RANGE 0x21
#define INVALID_COMMAND_OPCODE 0x20
#define INVALID_FIELD_IN_CDB 0x24
#define INVALID_FIELD_IN_PARAM_LIST 0x26
#define UA_RESET_ASC 0x29
#define UA_CHANGED_ASC 0x2a
#define POWER_ON_RESET_ASCQ 0x0
#define BUS_RESET_ASCQ 0x2	/* scsi bus reset occurred */
#define MODE_CHANGED_ASCQ 0x1	/* mode parameters changed */
#define SAVING_PARAMS_UNSUP 0x39
#define TRANSPORT_PROBLEM 0x4b
#define THRESHOLD_EXCEEDED 0x5d
#define LOW_POWER_COND_ON 0x5e

/* Additional Sense Code Qualifier (ASCQ) */
#define ACK_NAK_TO 0x3


/* Default values for driver parameters */
#define DEF_NUM_HOST   1
#define DEF_NUM_TGTS   1
#define DEF_MAX_LUNS   1
/* With these defaults, this driver will make 1 host with 1 target
 * (id 0) containing 1 logical unit (lun 0). That is 1 device.
 */
#define DEF_ATO 1
#define DEF_DELAY   1		/* if > 0 unit is a jiffy */
#define DEF_DEV_SIZE_MB   8
#define DEF_DIF 0
#define DEF_DIX 0
#define DEF_D_SENSE   0
#define DEF_EVERY_NTH   0
#define DEF_FAKE_RW	0
#define DEF_GUARD 0
#define DEF_HOST_LOCK 0
#define DEF_LBPU 0
#define DEF_LBPWS 0
#define DEF_LBPWS10 0
#define DEF_LBPRZ 1
#define DEF_LOWEST_ALIGNED 0
#define DEF_NDELAY   0		/* if > 0 unit is a nanosecond */
#define DEF_NO_LUN_0   0
#define DEF_NUM_PARTS   0
#define DEF_OPTS   0
#define DEF_OPT_BLKS 64
#define DEF_PHYSBLK_EXP 0
#define DEF_PTYPE   0
#define DEF_REMOVABLE false
#define DEF_SCSI_LEVEL   6    /* INQUIRY, byte2 [6->SPC-4] */
#define DEF_SECTOR_SIZE 512
#define DEF_TAGGED_QUEUING 0 /* 0 | MSG_SIMPLE_TAG | MSG_ORDERED_TAG */
#define DEF_UNMAP_ALIGNMENT 0
#define DEF_UNMAP_GRANULARITY 1
#define DEF_UNMAP_MAX_BLOCKS 0xFFFFFFFF
#define DEF_UNMAP_MAX_DESC 256
#define DEF_VIRTUAL_GB   0
#define DEF_VPD_USE_HOSTNO 1
#define DEF_WRITESAME_LENGTH 0xFFFF
#define DELAY_OVERRIDDEN -9999

/* bit mask values for scsi_debug_opts */
#define SCSI_DEBUG_OPT_NOISE   1
#define SCSI_DEBUG_OPT_MEDIUM_ERR   2
#define SCSI_DEBUG_OPT_TIMEOUT   4
#define SCSI_DEBUG_OPT_RECOVERED_ERR   8
#define SCSI_DEBUG_OPT_TRANSPORT_ERR   16
#define SCSI_DEBUG_OPT_DIF_ERR   32
#define SCSI_DEBUG_OPT_DIX_ERR   64
#define SCSI_DEBUG_OPT_MAC_TIMEOUT  128
#define SCSI_DEBUG_OPT_SHORT_TRANSFER	0x100
#define SCSI_DEBUG_OPT_Q_NOISE	0x200
#define SCSI_DEBUG_OPT_ALL_TSF	0x400
#define SCSI_DEBUG_OPT_RARE_TSF	0x800
#define SCSI_DEBUG_OPT_N_WCE	0x1000
#define SCSI_DEBUG_OPT_RESET_NOISE 0x2000
#define SCSI_DEBUG_OPT_NO_CDB_NOISE 0x4000
#define SCSI_DEBUG_OPT_ALL_NOISE (0x1 | 0x200 | 0x2000)
/* When "every_nth" > 0 then modulo "every_nth" commands:
 *   - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
 *   - a RECOVERED_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_RECOVERED_ERR is set.
 *   - a TRANSPORT_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_TRANSPORT_ERR is set.
 *
 * When "every_nth" < 0 then after "- every_nth" commands:
 *   - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
 *   - a RECOVERED_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_RECOVERED_ERR is set.
 *   - a TRANSPORT_ERROR is simulated on successful read and write
 *     commands if SCSI_DEBUG_OPT_TRANSPORT_ERR is set.
 * This will continue until some other action occurs (e.g. the user
 * writing a new value (other than -1 or 1) to every_nth via sysfs).
 */

/* As indicated in SAM-5 and SPC-4 Unit Attentions (UAs)are returned in
 * priority order. In the subset implemented here lower numbers have higher
 * priority. The UA numbers should be a sequence starting from 0 with
 * SDEBUG_NUM_UAS being 1 higher than the highest numbered UA. */
#define SDEBUG_UA_POR 0		/* Power on, reset, or bus device reset */
#define SDEBUG_UA_BUS_RESET 1
#define SDEBUG_UA_MODE_CHANGED 2
#define SDEBUG_NUM_UAS 3

/* for check_readiness() */
#define UAS_ONLY 1
#define UAS_TUR 0

/* when 1==SCSI_DEBUG_OPT_MEDIUM_ERR, a medium error is simulated at this
 * sector on read commands: */
#define OPT_MEDIUM_ERR_ADDR   0x1234 /* that's sector 4660 in decimal */
#define OPT_MEDIUM_ERR_NUM    10     /* number of consecutive medium errs */

/* If REPORT LUNS has luns >= 256 it can choose "flat space" (value 1)
 * or "peripheral device" addressing (value 0) */
#define SAM2_LUN_ADDRESS_METHOD 0
#define SAM2_WLUN_REPORT_LUNS 0xc101

/* SCSI_DEBUG_CANQUEUE is the maximum number of commands that can be queued
 * (for response) at one time. Can be reduced by max_queue option. Command
 * responses are not queued when delay=0 and ndelay=0. The per-device
 * DEF_CMD_PER_LUN can be changed via sysfs:
 * /sys/class/scsi_device/<h:c:t:l>/device/queue_depth but cannot exceed
 * SCSI_DEBUG_CANQUEUE. */
#define SCSI_DEBUG_CANQUEUE_WORDS  9	/* a WORD is bits in a long */
#define SCSI_DEBUG_CANQUEUE  (SCSI_DEBUG_CANQUEUE_WORDS * BITS_PER_LONG)
#define DEF_CMD_PER_LUN  255

#if DEF_CMD_PER_LUN > SCSI_DEBUG_CANQUEUE
#warning "Expect DEF_CMD_PER_LUN <= SCSI_DEBUG_CANQUEUE"
#endif

static int scsi_debug_add_host = DEF_NUM_HOST;
static int scsi_debug_ato = DEF_ATO;
static int scsi_debug_delay = DEF_DELAY;
static int scsi_debug_dev_size_mb = DEF_DEV_SIZE_MB;
static int scsi_debug_dif = DEF_DIF;
static int scsi_debug_dix = DEF_DIX;
static int scsi_debug_dsense = DEF_D_SENSE;
static int scsi_debug_every_nth = DEF_EVERY_NTH;
static int scsi_debug_fake_rw = DEF_FAKE_RW;
static unsigned int scsi_debug_guard = DEF_GUARD;
static int scsi_debug_lowest_aligned = DEF_LOWEST_ALIGNED;
static int scsi_debug_max_luns = DEF_MAX_LUNS;
static int scsi_debug_max_queue = SCSI_DEBUG_CANQUEUE;
static atomic_t retired_max_queue;	/* if > 0 then was prior max_queue */
static int scsi_debug_ndelay = DEF_NDELAY;
static int scsi_debug_no_lun_0 = DEF_NO_LUN_0;
static int scsi_debug_no_uld = 0;
static int scsi_debug_num_parts = DEF_NUM_PARTS;
static int scsi_debug_num_tgts = DEF_NUM_TGTS; /* targets per host */
static int scsi_debug_opt_blks = DEF_OPT_BLKS;
static int scsi_debug_opts = DEF_OPTS;
static int scsi_debug_physblk_exp = DEF_PHYSBLK_EXP;
static int scsi_debug_ptype = DEF_PTYPE; /* SCSI peripheral type (0==disk) */
static int scsi_debug_scsi_level = DEF_SCSI_LEVEL;
static int scsi_debug_sector_size = DEF_SECTOR_SIZE;
static int scsi_debug_virtual_gb = DEF_VIRTUAL_GB;
static int scsi_debug_vpd_use_hostno = DEF_VPD_USE_HOSTNO;
static unsigned int scsi_debug_lbpu = DEF_LBPU;
static unsigned int scsi_debug_lbpws = DEF_LBPWS;
static unsigned int scsi_debug_lbpws10 = DEF_LBPWS10;
static unsigned int scsi_debug_lbprz = DEF_LBPRZ;
static unsigned int scsi_debug_unmap_alignment = DEF_UNMAP_ALIGNMENT;
static unsigned int scsi_debug_unmap_granularity = DEF_UNMAP_GRANULARITY;
static unsigned int scsi_debug_unmap_max_blocks = DEF_UNMAP_MAX_BLOCKS;
static unsigned int scsi_debug_unmap_max_desc = DEF_UNMAP_MAX_DESC;
static unsigned int scsi_debug_write_same_length = DEF_WRITESAME_LENGTH;
static bool scsi_debug_removable = DEF_REMOVABLE;
static bool scsi_debug_clustering;
static bool scsi_debug_host_lock = DEF_HOST_LOCK;

static atomic_t sdebug_cmnd_count;
static atomic_t sdebug_completions;
static atomic_t sdebug_a_tsf;		/* counter of 'almost' TSFs */

#define DEV_READONLY(TGT)      (0)

static unsigned int sdebug_store_sectors;
static sector_t sdebug_capacity;	/* in sectors */

/* old BIOS stuff, kernel may get rid of them but some mode sense pages
   may still need them */
static int sdebug_heads;		/* heads per disk */
static int sdebug_cylinders_per;	/* cylinders per surface */
static int sdebug_sectors_per;		/* sectors per cylinder */

#define SDEBUG_MAX_PARTS 4

#define SCSI_DEBUG_MAX_CMD_LEN 32

static unsigned int scsi_debug_lbp(void)
{
	return ((0 == scsi_debug_fake_rw) &&
		(scsi_debug_lbpu | scsi_debug_lbpws | scsi_debug_lbpws10));
}

struct sdebug_dev_info {
	struct list_head dev_list;
	unsigned int channel;
	unsigned int target;
	u64 lun;
	struct sdebug_host_info *sdbg_host;
	u64 wlun;
	unsigned long uas_bm[1];
	atomic_t num_in_q;
	char stopped;
	char used;
};

struct sdebug_host_info {
	struct list_head host_list;
	struct Scsi_Host *shost;
	struct device dev;
	struct list_head dev_info_list;
};

#define to_sdebug_host(d)	\
	container_of(d, struct sdebug_host_info, dev)

static LIST_HEAD(sdebug_host_list);
static DEFINE_SPINLOCK(sdebug_host_list_lock);


struct sdebug_hrtimer {		/* ... is derived from hrtimer */
	struct hrtimer hrt;	/* must be first element */
	int qa_indx;
};

struct sdebug_queued_cmd {
	/* in_use flagged by a bit in queued_in_use_bm[] */
	struct timer_list *cmnd_timerp;
	struct tasklet_struct *tletp;
	struct sdebug_hrtimer *sd_hrtp;
	struct scsi_cmnd * a_cmnd;
};
static struct sdebug_queued_cmd queued_arr[SCSI_DEBUG_CANQUEUE];
static unsigned long queued_in_use_bm[SCSI_DEBUG_CANQUEUE_WORDS];


static unsigned char * fake_storep;	/* ramdisk storage */
static struct sd_dif_tuple *dif_storep;	/* protection info */
static void *map_storep;		/* provisioning map */

static unsigned long map_size;
static int num_aborts;
static int num_dev_resets;
static int num_target_resets;
static int num_bus_resets;
static int num_host_resets;
static int dix_writes;
static int dix_reads;
static int dif_errors;

static DEFINE_SPINLOCK(queued_arr_lock);
static DEFINE_RWLOCK(atomic_rw);

static char sdebug_proc_name[] = MY_NAME;
static const char *my_name = MY_NAME;

static struct bus_type pseudo_lld_bus;

static struct device_driver sdebug_driverfs_driver = {
	.name 		= sdebug_proc_name,
	.bus		= &pseudo_lld_bus,
};

static const int check_condition_result =
		(DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;

static const int illegal_condition_result =
	(DRIVER_SENSE << 24) | (DID_ABORT << 16) | SAM_STAT_CHECK_CONDITION;

static const int device_qfull_result =
	(DID_OK << 16) | (COMMAND_COMPLETE << 8) | SAM_STAT_TASK_SET_FULL;

static unsigned char caching_pg[] = {0x8, 18, 0x14, 0, 0xff, 0xff, 0, 0,
				     0xff, 0xff, 0xff, 0xff, 0x80, 0x14, 0, 0,
				     0, 0, 0, 0};
static unsigned char ctrl_m_pg[] = {0xa, 10, 2, 0, 0, 0, 0, 0,
				    0, 0, 0x2, 0x4b};
static unsigned char iec_m_pg[] = {0x1c, 0xa, 0x08, 0, 0, 0, 0, 0,
			           0, 0, 0x0, 0x0};

static void *fake_store(unsigned long long lba)
{
	lba = do_div(lba, sdebug_store_sectors);

	return fake_storep + lba * scsi_debug_sector_size;
}

static struct sd_dif_tuple *dif_store(sector_t sector)
{
	sector = do_div(sector, sdebug_store_sectors);

	return dif_storep + sector;
}

static int sdebug_add_adapter(void);
static void sdebug_remove_adapter(void);

static void sdebug_max_tgts_luns(void)
{
	struct sdebug_host_info *sdbg_host;
	struct Scsi_Host *hpnt;

	spin_lock(&sdebug_host_list_lock);
	list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
		hpnt = sdbg_host->shost;
		if ((hpnt->this_id >= 0) &&
		    (scsi_debug_num_tgts > hpnt->this_id))
			hpnt->max_id = scsi_debug_num_tgts + 1;
		else
			hpnt->max_id = scsi_debug_num_tgts;
		/* scsi_debug_max_luns; */
		hpnt->max_lun = SAM2_WLUN_REPORT_LUNS;
	}
	spin_unlock(&sdebug_host_list_lock);
}

static void mk_sense_buffer(struct scsi_cmnd *scp, int key, int asc, int asq)
{
	unsigned char *sbuff;

	sbuff = scp->sense_buffer;
	if (!sbuff) {
		sdev_printk(KERN_ERR, scp->device,
			    "%s: sense_buffer is NULL\n", __func__);
		return;
	}
	memset(sbuff, 0, SCSI_SENSE_BUFFERSIZE);

	scsi_build_sense_buffer(scsi_debug_dsense, sbuff, key, asc, asq);

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, scp->device,
			    "%s:  [sense_key,asc,ascq]: [0x%x,0x%x,0x%x]\n",
			    my_name, key, asc, asq);
}

static void get_data_transfer_info(unsigned char *cmd,
				   unsigned long long *lba, unsigned int *num,
				   u32 *ei_lba)
{
	*ei_lba = 0;

	switch (*cmd) {
	case VARIABLE_LENGTH_CMD:
		*lba = (u64)cmd[19] | (u64)cmd[18] << 8 |
			(u64)cmd[17] << 16 | (u64)cmd[16] << 24 |
			(u64)cmd[15] << 32 | (u64)cmd[14] << 40 |
			(u64)cmd[13] << 48 | (u64)cmd[12] << 56;

		*ei_lba = (u32)cmd[23] | (u32)cmd[22] << 8 |
			(u32)cmd[21] << 16 | (u32)cmd[20] << 24;

		*num = (u32)cmd[31] | (u32)cmd[30] << 8 | (u32)cmd[29] << 16 |
			(u32)cmd[28] << 24;
		break;

	case WRITE_SAME_16:
	case WRITE_16:
	case READ_16:
		*lba = (u64)cmd[9] | (u64)cmd[8] << 8 |
			(u64)cmd[7] << 16 | (u64)cmd[6] << 24 |
			(u64)cmd[5] << 32 | (u64)cmd[4] << 40 |
			(u64)cmd[3] << 48 | (u64)cmd[2] << 56;

		*num = (u32)cmd[13] | (u32)cmd[12] << 8 | (u32)cmd[11] << 16 |
			(u32)cmd[10] << 24;
		break;
	case WRITE_12:
	case READ_12:
		*lba = (u32)cmd[5] | (u32)cmd[4] << 8 | (u32)cmd[3] << 16 |
			(u32)cmd[2] << 24;

		*num = (u32)cmd[9] | (u32)cmd[8] << 8 | (u32)cmd[7] << 16 |
			(u32)cmd[6] << 24;
		break;
	case WRITE_SAME:
	case WRITE_10:
	case READ_10:
	case XDWRITEREAD_10:
		*lba = (u32)cmd[5] | (u32)cmd[4] << 8 |	(u32)cmd[3] << 16 |
			(u32)cmd[2] << 24;

		*num = (u32)cmd[8] | (u32)cmd[7] << 8;
		break;
	case WRITE_6:
	case READ_6:
		*lba = (u32)cmd[3] | (u32)cmd[2] << 8 |
			(u32)(cmd[1] & 0x1f) << 16;
		*num = (0 == cmd[4]) ? 256 : cmd[4];
		break;
	default:
		break;
	}
}

static int scsi_debug_ioctl(struct scsi_device *dev, int cmd, void __user *arg)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) {
		if (0x1261 == cmd)
			sdev_printk(KERN_INFO, dev,
				    "%s: BLKFLSBUF [0x1261]\n", __func__);
		else if (0x5331 == cmd)
			sdev_printk(KERN_INFO, dev,
				    "%s: CDROM_GET_CAPABILITY [0x5331]\n",
				    __func__);
		else
			sdev_printk(KERN_INFO, dev, "%s: cmd=0x%x\n",
				    __func__, cmd);
	}
	return -EINVAL;
	/* return -ENOTTY; // correct return but upsets fdisk */
}

static int check_readiness(struct scsi_cmnd *SCpnt, int uas_only,
			   struct sdebug_dev_info * devip)
{
	int k;
	bool debug = !!(SCSI_DEBUG_OPT_NOISE & scsi_debug_opts);

	k = find_first_bit(devip->uas_bm, SDEBUG_NUM_UAS);
	if (k != SDEBUG_NUM_UAS) {
		const char *cp = NULL;

		switch (k) {
		case SDEBUG_UA_POR:
			mk_sense_buffer(SCpnt, UNIT_ATTENTION,
					UA_RESET_ASC, POWER_ON_RESET_ASCQ);
			if (debug)
				cp = "power on reset";
			break;
		case SDEBUG_UA_BUS_RESET:
			mk_sense_buffer(SCpnt, UNIT_ATTENTION,
					UA_RESET_ASC, BUS_RESET_ASCQ);
			if (debug)
				cp = "bus reset";
			break;
		case SDEBUG_UA_MODE_CHANGED:
			mk_sense_buffer(SCpnt, UNIT_ATTENTION,
					UA_CHANGED_ASC, MODE_CHANGED_ASCQ);
			if (debug)
				cp = "mode parameters changed";
			break;
		default:
			pr_warn("%s: unexpected unit attention code=%d\n",
				__func__, k);
			if (debug)
				cp = "unknown";
			break;
		}
		clear_bit(k, devip->uas_bm);
		if (debug)
			sdev_printk(KERN_INFO, SCpnt->device,
				   "%s reports: Unit attention: %s\n",
				   my_name, cp);
		return check_condition_result;
	}
	if ((UAS_TUR == uas_only) && devip->stopped) {
		mk_sense_buffer(SCpnt, NOT_READY, LOGICAL_UNIT_NOT_READY,
				0x2);
		if (debug)
			sdev_printk(KERN_INFO, SCpnt->device,
				    "%s reports: Not ready: %s\n", my_name,
				    "initializing command required");
		return check_condition_result;
	}
	return 0;
}

/* Returns 0 if ok else (DID_ERROR << 16). Sets scp->resid . */
static int fill_from_dev_buffer(struct scsi_cmnd *scp, unsigned char *arr,
				int arr_len)
{
	int act_len;
	struct scsi_data_buffer *sdb = scsi_in(scp);

	if (!sdb->length)
		return 0;
	if (!(scsi_bidi_cmnd(scp) || scp->sc_data_direction == DMA_FROM_DEVICE))
		return (DID_ERROR << 16);

	act_len = sg_copy_from_buffer(sdb->table.sgl, sdb->table.nents,
				      arr, arr_len);
	sdb->resid = scsi_bufflen(scp) - act_len;

	return 0;
}

/* Returns number of bytes fetched into 'arr' or -1 if error. */
static int fetch_to_dev_buffer(struct scsi_cmnd *scp, unsigned char *arr,
			       int arr_len)
{
	if (!scsi_bufflen(scp))
		return 0;
	if (!(scsi_bidi_cmnd(scp) || scp->sc_data_direction == DMA_TO_DEVICE))
		return -1;

	return scsi_sg_copy_to_buffer(scp, arr, arr_len);
}


static const char * inq_vendor_id = "Linux   ";
static const char * inq_product_id = "scsi_debug      ";
static const char *inq_product_rev = "0184";	/* version less '.' */

/* Device identification VPD page. Returns number of bytes placed in arr */
static int inquiry_evpd_83(unsigned char * arr, int port_group_id,
			   int target_dev_id, int dev_id_num,
			   const char * dev_id_str,
			   int dev_id_str_len)
{
	int num, port_a;
	char b[32];

	port_a = target_dev_id + 1;
	/* T10 vendor identifier field format (faked) */
	arr[0] = 0x2;	/* ASCII */
	arr[1] = 0x1;
	arr[2] = 0x0;
	memcpy(&arr[4], inq_vendor_id, 8);
	memcpy(&arr[12], inq_product_id, 16);
	memcpy(&arr[28], dev_id_str, dev_id_str_len);
	num = 8 + 16 + dev_id_str_len;
	arr[3] = num;
	num += 4;
	if (dev_id_num >= 0) {
		/* NAA-5, Logical unit identifier (binary) */
		arr[num++] = 0x1;	/* binary (not necessarily sas) */
		arr[num++] = 0x3;	/* PIV=0, lu, naa */
		arr[num++] = 0x0;
		arr[num++] = 0x8;
		arr[num++] = 0x53;  /* naa-5 ieee company id=0x333333 (fake) */
		arr[num++] = 0x33;
		arr[num++] = 0x33;
		arr[num++] = 0x30;
		arr[num++] = (dev_id_num >> 24);
		arr[num++] = (dev_id_num >> 16) & 0xff;
		arr[num++] = (dev_id_num >> 8) & 0xff;
		arr[num++] = dev_id_num & 0xff;
		/* Target relative port number */
		arr[num++] = 0x61;	/* proto=sas, binary */
		arr[num++] = 0x94;	/* PIV=1, target port, rel port */
		arr[num++] = 0x0;	/* reserved */
		arr[num++] = 0x4;	/* length */
		arr[num++] = 0x0;	/* reserved */
		arr[num++] = 0x0;	/* reserved */
		arr[num++] = 0x0;
		arr[num++] = 0x1;	/* relative port A */
	}
	/* NAA-5, Target port identifier */
	arr[num++] = 0x61;	/* proto=sas, binary */
	arr[num++] = 0x93;	/* piv=1, target port, naa */
	arr[num++] = 0x0;
	arr[num++] = 0x8;
	arr[num++] = 0x52;	/* naa-5, company id=0x222222 (fake) */
	arr[num++] = 0x22;
	arr[num++] = 0x22;
	arr[num++] = 0x20;
	arr[num++] = (port_a >> 24);
	arr[num++] = (port_a >> 16) & 0xff;
	arr[num++] = (port_a >> 8) & 0xff;
	arr[num++] = port_a & 0xff;
	/* NAA-5, Target port group identifier */
	arr[num++] = 0x61;	/* proto=sas, binary */
	arr[num++] = 0x95;	/* piv=1, target port group id */
	arr[num++] = 0x0;
	arr[num++] = 0x4;
	arr[num++] = 0;
	arr[num++] = 0;
	arr[num++] = (port_group_id >> 8) & 0xff;
	arr[num++] = port_group_id & 0xff;
	/* NAA-5, Target device identifier */
	arr[num++] = 0x61;	/* proto=sas, binary */
	arr[num++] = 0xa3;	/* piv=1, target device, naa */
	arr[num++] = 0x0;
	arr[num++] = 0x8;
	arr[num++] = 0x52;	/* naa-5, company id=0x222222 (fake) */
	arr[num++] = 0x22;
	arr[num++] = 0x22;
	arr[num++] = 0x20;
	arr[num++] = (target_dev_id >> 24);
	arr[num++] = (target_dev_id >> 16) & 0xff;
	arr[num++] = (target_dev_id >> 8) & 0xff;
	arr[num++] = target_dev_id & 0xff;
	/* SCSI name string: Target device identifier */
	arr[num++] = 0x63;	/* proto=sas, UTF-8 */
	arr[num++] = 0xa8;	/* piv=1, target device, SCSI name string */
	arr[num++] = 0x0;
	arr[num++] = 24;
	memcpy(arr + num, "naa.52222220", 12);
	num += 12;
	snprintf(b, sizeof(b), "%08X", target_dev_id);
	memcpy(arr + num, b, 8);
	num += 8;
	memset(arr + num, 0, 4);
	num += 4;
	return num;
}


static unsigned char vpd84_data[] = {
/* from 4th byte */ 0x22,0x22,0x22,0x0,0xbb,0x0,
    0x22,0x22,0x22,0x0,0xbb,0x1,
    0x22,0x22,0x22,0x0,0xbb,0x2,
};

/*  Software interface identification VPD page */
static int inquiry_evpd_84(unsigned char * arr)
{
	memcpy(arr, vpd84_data, sizeof(vpd84_data));
	return sizeof(vpd84_data);
}

/* Management network addresses VPD page */
static int inquiry_evpd_85(unsigned char * arr)
{
	int num = 0;
	const char * na1 = "https://www.kernel.org/config";
	const char * na2 = "http://www.kernel.org/log";
	int plen, olen;

	arr[num++] = 0x1;	/* lu, storage config */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;
	olen = strlen(na1);
	plen = olen + 1;
	if (plen % 4)
		plen = ((plen / 4) + 1) * 4;
	arr[num++] = plen;	/* length, null termianted, padded */
	memcpy(arr + num, na1, olen);
	memset(arr + num + olen, 0, plen - olen);
	num += plen;

	arr[num++] = 0x4;	/* lu, logging */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;
	olen = strlen(na2);
	plen = olen + 1;
	if (plen % 4)
		plen = ((plen / 4) + 1) * 4;
	arr[num++] = plen;	/* length, null terminated, padded */
	memcpy(arr + num, na2, olen);
	memset(arr + num + olen, 0, plen - olen);
	num += plen;

	return num;
}

/* SCSI ports VPD page */
static int inquiry_evpd_88(unsigned char * arr, int target_dev_id)
{
	int num = 0;
	int port_a, port_b;

	port_a = target_dev_id + 1;
	port_b = port_a + 1;
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;
	arr[num++] = 0x1;	/* relative port 1 (primary) */
	memset(arr + num, 0, 6);
	num += 6;
	arr[num++] = 0x0;
	arr[num++] = 12;	/* length tp descriptor */
	/* naa-5 target port identifier (A) */
	arr[num++] = 0x61;	/* proto=sas, binary */
	arr[num++] = 0x93;	/* PIV=1, target port, NAA */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x8;	/* length */
	arr[num++] = 0x52;	/* NAA-5, company_id=0x222222 (fake) */
	arr[num++] = 0x22;
	arr[num++] = 0x22;
	arr[num++] = 0x20;
	arr[num++] = (port_a >> 24);
	arr[num++] = (port_a >> 16) & 0xff;
	arr[num++] = (port_a >> 8) & 0xff;
	arr[num++] = port_a & 0xff;

	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x0;
	arr[num++] = 0x2;	/* relative port 2 (secondary) */
	memset(arr + num, 0, 6);
	num += 6;
	arr[num++] = 0x0;
	arr[num++] = 12;	/* length tp descriptor */
	/* naa-5 target port identifier (B) */
	arr[num++] = 0x61;	/* proto=sas, binary */
	arr[num++] = 0x93;	/* PIV=1, target port, NAA */
	arr[num++] = 0x0;	/* reserved */
	arr[num++] = 0x8;	/* length */
	arr[num++] = 0x52;	/* NAA-5, company_id=0x222222 (fake) */
	arr[num++] = 0x22;
	arr[num++] = 0x22;
	arr[num++] = 0x20;
	arr[num++] = (port_b >> 24);
	arr[num++] = (port_b >> 16) & 0xff;
	arr[num++] = (port_b >> 8) & 0xff;
	arr[num++] = port_b & 0xff;

	return num;
}


static unsigned char vpd89_data[] = {
/* from 4th byte */ 0,0,0,0,
'l','i','n','u','x',' ',' ',' ',
'S','A','T',' ','s','c','s','i','_','d','e','b','u','g',' ',' ',
'1','2','3','4',
0x34,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,
0xec,0,0,0,
0x5a,0xc,0xff,0x3f,0x37,0xc8,0x10,0,0,0,0,0,0x3f,0,0,0,
0,0,0,0,0x58,0x58,0x58,0x58,0x58,0x58,0x58,0x58,0x20,0x20,0x20,0x20,
0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0,0,0,0x40,0x4,0,0x2e,0x33,
0x38,0x31,0x20,0x20,0x20,0x20,0x54,0x53,0x38,0x33,0x30,0x30,0x33,0x31,
0x53,0x41,
0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,
0x20,0x20,
0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x20,
0x10,0x80,
0,0,0,0x2f,0,0,0,0x2,0,0x2,0x7,0,0xff,0xff,0x1,0,
0x3f,0,0xc1,0xff,0x3e,0,0x10,0x1,0xb0,0xf8,0x50,0x9,0,0,0x7,0,
0x3,0,0x78,0,0x78,0,0xf0,0,0x78,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0x2,0,0,0,0,0,0,0,
0x7e,0,0x1b,0,0x6b,0x34,0x1,0x7d,0x3,0x40,0x69,0x34,0x1,0x3c,0x3,0x40,
0x7f,0x40,0,0,0,0,0xfe,0xfe,0,0,0,0,0,0xfe,0,0,
0,0,0,0,0,0,0,0,0xb0,0xf8,0x50,0x9,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0x1,0,0xb0,0xf8,0x50,0x9,0xb0,0xf8,0x50,0x9,0x20,0x20,0x2,0,0xb6,0x42,
0,0x80,0x8a,0,0x6,0x3c,0xa,0x3c,0xff,0xff,0xc6,0x7,0,0x1,0,0x8,
0xf0,0xf,0,0x10,0x2,0,0x30,0,0,0,0,0,0,0,0x6,0xfe,
0,0,0x2,0,0x50,0,0x8a,0,0x4f,0x95,0,0,0x21,0,0xb,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0xa5,0x51,
};

/* ATA Information VPD page */
static int inquiry_evpd_89(unsigned char * arr)
{
	memcpy(arr, vpd89_data, sizeof(vpd89_data));
	return sizeof(vpd89_data);
}


static unsigned char vpdb0_data[] = {
	/* from 4th byte */ 0,0,0,4, 0,0,0x4,0, 0,0,0,64,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
};

/* Block limits VPD page (SBC-3) */
static int inquiry_evpd_b0(unsigned char * arr)
{
	unsigned int gran;

	memcpy(arr, vpdb0_data, sizeof(vpdb0_data));

	/* Optimal transfer length granularity */
	gran = 1 << scsi_debug_physblk_exp;
	arr[2] = (gran >> 8) & 0xff;
	arr[3] = gran & 0xff;

	/* Maximum Transfer Length */
	if (sdebug_store_sectors > 0x400) {
		arr[4] = (sdebug_store_sectors >> 24) & 0xff;
		arr[5] = (sdebug_store_sectors >> 16) & 0xff;
		arr[6] = (sdebug_store_sectors >> 8) & 0xff;
		arr[7] = sdebug_store_sectors & 0xff;
	}

	/* Optimal Transfer Length */
	put_unaligned_be32(scsi_debug_opt_blks, &arr[8]);

	if (scsi_debug_lbpu) {
		/* Maximum Unmap LBA Count */
		put_unaligned_be32(scsi_debug_unmap_max_blocks, &arr[16]);

		/* Maximum Unmap Block Descriptor Count */
		put_unaligned_be32(scsi_debug_unmap_max_desc, &arr[20]);
	}

	/* Unmap Granularity Alignment */
	if (scsi_debug_unmap_alignment) {
		put_unaligned_be32(scsi_debug_unmap_alignment, &arr[28]);
		arr[28] |= 0x80; /* UGAVALID */
	}

	/* Optimal Unmap Granularity */
	put_unaligned_be32(scsi_debug_unmap_granularity, &arr[24]);

	/* Maximum WRITE SAME Length */
	put_unaligned_be64(scsi_debug_write_same_length, &arr[32]);

	return 0x3c; /* Mandatory page length for Logical Block Provisioning */

	return sizeof(vpdb0_data);
}

/* Block device characteristics VPD page (SBC-3) */
static int inquiry_evpd_b1(unsigned char *arr)
{
	memset(arr, 0, 0x3c);
	arr[0] = 0;
	arr[1] = 1;	/* non rotating medium (e.g. solid state) */
	arr[2] = 0;
	arr[3] = 5;	/* less than 1.8" */

	return 0x3c;
}

/* Logical block provisioning VPD page (SBC-3) */
static int inquiry_evpd_b2(unsigned char *arr)
{
	memset(arr, 0, 0x4);
	arr[0] = 0;			/* threshold exponent */

	if (scsi_debug_lbpu)
		arr[1] = 1 << 7;

	if (scsi_debug_lbpws)
		arr[1] |= 1 << 6;

	if (scsi_debug_lbpws10)
		arr[1] |= 1 << 5;

	if (scsi_debug_lbprz)
		arr[1] |= 1 << 2;

	return 0x4;
}

#define SDEBUG_LONG_INQ_SZ 96
#define SDEBUG_MAX_INQ_ARR_SZ 584

static int resp_inquiry(struct scsi_cmnd *scp, int target,
			struct sdebug_dev_info * devip)
{
	unsigned char pq_pdt;
	unsigned char * arr;
	unsigned char *cmd = scp->cmnd;
	int alloc_len, n, ret;

	alloc_len = (cmd[3] << 8) + cmd[4];
	arr = kzalloc(SDEBUG_MAX_INQ_ARR_SZ, GFP_ATOMIC);
	if (! arr)
		return DID_REQUEUE << 16;
	if (devip->wlun)
		pq_pdt = 0x1e;	/* present, wlun */
	else if (scsi_debug_no_lun_0 && (0 == devip->lun))
		pq_pdt = 0x7f;	/* not present, no device type */
	else
		pq_pdt = (scsi_debug_ptype & 0x1f);
	arr[0] = pq_pdt;
	if (0x2 & cmd[1]) {  /* CMDDT bit set */
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		kfree(arr);
		return check_condition_result;
	} else if (0x1 & cmd[1]) {  /* EVPD bit set */
		int lu_id_num, port_group_id, target_dev_id, len;
		char lu_id_str[6];
		int host_no = devip->sdbg_host->shost->host_no;
		
		port_group_id = (((host_no + 1) & 0x7f) << 8) +
		    (devip->channel & 0x7f);
		if (0 == scsi_debug_vpd_use_hostno)
			host_no = 0;
		lu_id_num = devip->wlun ? -1 : (((host_no + 1) * 2000) +
			    (devip->target * 1000) + devip->lun);
		target_dev_id = ((host_no + 1) * 2000) +
				 (devip->target * 1000) - 3;
		len = scnprintf(lu_id_str, 6, "%d", lu_id_num);
		if (0 == cmd[2]) { /* supported vital product data pages */
			arr[1] = cmd[2];	/*sanity */
			n = 4;
			arr[n++] = 0x0;   /* this page */
			arr[n++] = 0x80;  /* unit serial number */
			arr[n++] = 0x83;  /* device identification */
			arr[n++] = 0x84;  /* software interface ident. */
			arr[n++] = 0x85;  /* management network addresses */
			arr[n++] = 0x86;  /* extended inquiry */
			arr[n++] = 0x87;  /* mode page policy */
			arr[n++] = 0x88;  /* SCSI ports */
			arr[n++] = 0x89;  /* ATA information */
			arr[n++] = 0xb0;  /* Block limits (SBC) */
			arr[n++] = 0xb1;  /* Block characteristics (SBC) */
			if (scsi_debug_lbp()) /* Logical Block Prov. (SBC) */
				arr[n++] = 0xb2;
			arr[3] = n - 4;	  /* number of supported VPD pages */
		} else if (0x80 == cmd[2]) { /* unit serial number */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = len;
			memcpy(&arr[4], lu_id_str, len);
		} else if (0x83 == cmd[2]) { /* device identification */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = inquiry_evpd_83(&arr[4], port_group_id,
						 target_dev_id, lu_id_num,
						 lu_id_str, len);
		} else if (0x84 == cmd[2]) { /* Software interface ident. */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = inquiry_evpd_84(&arr[4]);
		} else if (0x85 == cmd[2]) { /* Management network addresses */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = inquiry_evpd_85(&arr[4]);
		} else if (0x86 == cmd[2]) { /* extended inquiry */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = 0x3c;	/* number of following entries */
			if (scsi_debug_dif == SD_DIF_TYPE3_PROTECTION)
				arr[4] = 0x4;	/* SPT: GRD_CHK:1 */
			else if (scsi_debug_dif)
				arr[4] = 0x5;   /* SPT: GRD_CHK:1, REF_CHK:1 */
			else
				arr[4] = 0x0;   /* no protection stuff */
			arr[5] = 0x7;   /* head of q, ordered + simple q's */
		} else if (0x87 == cmd[2]) { /* mode page policy */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = 0x8;	/* number of following entries */
			arr[4] = 0x2;	/* disconnect-reconnect mp */
			arr[6] = 0x80;	/* mlus, shared */
			arr[8] = 0x18;	 /* protocol specific lu */
			arr[10] = 0x82;	 /* mlus, per initiator port */
		} else if (0x88 == cmd[2]) { /* SCSI Ports */
			arr[1] = cmd[2];	/*sanity */
			arr[3] = inquiry_evpd_88(&arr[4], target_dev_id);
		} else if (0x89 == cmd[2]) { /* ATA information */
			arr[1] = cmd[2];        /*sanity */
			n = inquiry_evpd_89(&arr[4]);
			arr[2] = (n >> 8);
			arr[3] = (n & 0xff);
		} else if (0xb0 == cmd[2]) { /* Block limits (SBC) */
			arr[1] = cmd[2];        /*sanity */
			arr[3] = inquiry_evpd_b0(&arr[4]);
		} else if (0xb1 == cmd[2]) { /* Block characteristics (SBC) */
			arr[1] = cmd[2];        /*sanity */
			arr[3] = inquiry_evpd_b1(&arr[4]);
		} else if (0xb2 == cmd[2]) { /* Logical Block Prov. (SBC) */
			arr[1] = cmd[2];        /*sanity */
			arr[3] = inquiry_evpd_b2(&arr[4]);
		} else {
			/* Illegal request, invalid field in cdb */
			mk_sense_buffer(scp, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			kfree(arr);
			return check_condition_result;
		}
		len = min(((arr[2] << 8) + arr[3]) + 4, alloc_len);
		ret = fill_from_dev_buffer(scp, arr,
			    min(len, SDEBUG_MAX_INQ_ARR_SZ));
		kfree(arr);
		return ret;
	}
	/* drops through here for a standard inquiry */
	arr[1] = scsi_debug_removable ? 0x80 : 0;	/* Removable disk */
	arr[2] = scsi_debug_scsi_level;
	arr[3] = 2;    /* response_data_format==2 */
	arr[4] = SDEBUG_LONG_INQ_SZ - 5;
	arr[5] = scsi_debug_dif ? 1 : 0; /* PROTECT bit */
	if (0 == scsi_debug_vpd_use_hostno)
		arr[5] = 0x10; /* claim: implicit TGPS */
	arr[6] = 0x10; /* claim: MultiP */
	/* arr[6] |= 0x40; ... claim: EncServ (enclosure services) */
	arr[7] = 0xa; /* claim: LINKED + CMDQUE */
	memcpy(&arr[8], inq_vendor_id, 8);
	memcpy(&arr[16], inq_product_id, 16);
	memcpy(&arr[32], inq_product_rev, 4);
	/* version descriptors (2 bytes each) follow */
	arr[58] = 0x0; arr[59] = 0xa2;  /* SAM-5 rev 4 */
	arr[60] = 0x4; arr[61] = 0x68;  /* SPC-4 rev 37 */
	n = 62;
	if (scsi_debug_ptype == 0) {
		arr[n++] = 0x4; arr[n++] = 0xc5; /* SBC-4 rev 36 */
	} else if (scsi_debug_ptype == 1) {
		arr[n++] = 0x5; arr[n++] = 0x25; /* SSC-4 rev 3 */
	}
	arr[n++] = 0x20; arr[n++] = 0xe6;  /* SPL-3 rev 7 */
	ret = fill_from_dev_buffer(scp, arr,
			    min(alloc_len, SDEBUG_LONG_INQ_SZ));
	kfree(arr);
	return ret;
}

static int resp_requests(struct scsi_cmnd * scp,
			 struct sdebug_dev_info * devip)
{
	unsigned char * sbuff;
	unsigned char *cmd = scp->cmnd;
	unsigned char arr[SCSI_SENSE_BUFFERSIZE];
	int want_dsense;
	int len = 18;

	memset(arr, 0, sizeof(arr));
	want_dsense = !!(cmd[1] & 1) || scsi_debug_dsense;
	sbuff = scp->sense_buffer;
	if ((iec_m_pg[2] & 0x4) && (6 == (iec_m_pg[3] & 0xf))) {
		if (want_dsense) {
			arr[0] = 0x72;
			arr[1] = 0x0;		/* NO_SENSE in sense_key */
			arr[2] = THRESHOLD_EXCEEDED;
			arr[3] = 0xff;		/* TEST set and MRIE==6 */
		} else {
			arr[0] = 0x70;
			arr[2] = 0x0;		/* NO_SENSE in sense_key */
			arr[7] = 0xa;   	/* 18 byte sense buffer */
			arr[12] = THRESHOLD_EXCEEDED;
			arr[13] = 0xff;		/* TEST set and MRIE==6 */
		}
	} else {
		memcpy(arr, sbuff, SCSI_SENSE_BUFFERSIZE);
		if ((cmd[1] & 1) && (! scsi_debug_dsense)) {
			/* DESC bit set and sense_buff in fixed format */
			memset(arr, 0, sizeof(arr));
			arr[0] = 0x72;
			arr[1] = sbuff[2];     /* sense key */
			arr[2] = sbuff[12];    /* asc */
			arr[3] = sbuff[13];    /* ascq */
			len = 8;
		}
	}
	mk_sense_buffer(scp, 0, NO_ADDITIONAL_SENSE, 0);
	return fill_from_dev_buffer(scp, arr, len);
}

static int resp_start_stop(struct scsi_cmnd * scp,
			   struct sdebug_dev_info * devip)
{
	unsigned char *cmd = scp->cmnd;
	int power_cond, errsts, start;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	power_cond = (cmd[4] & 0xf0) >> 4;
	if (power_cond) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	start = cmd[4] & 1;
	if (start == devip->stopped)
		devip->stopped = !start;
	return 0;
}

static sector_t get_sdebug_capacity(void)
{
	if (scsi_debug_virtual_gb > 0)
		return (sector_t)scsi_debug_virtual_gb *
			(1073741824 / scsi_debug_sector_size);
	else
		return sdebug_store_sectors;
}

#define SDEBUG_READCAP_ARR_SZ 8
static int resp_readcap(struct scsi_cmnd * scp,
			struct sdebug_dev_info * devip)
{
	unsigned char arr[SDEBUG_READCAP_ARR_SZ];
	unsigned int capac;
	int errsts;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	/* following just in case virtual_gb changed */
	sdebug_capacity = get_sdebug_capacity();
	memset(arr, 0, SDEBUG_READCAP_ARR_SZ);
	if (sdebug_capacity < 0xffffffff) {
		capac = (unsigned int)sdebug_capacity - 1;
		arr[0] = (capac >> 24);
		arr[1] = (capac >> 16) & 0xff;
		arr[2] = (capac >> 8) & 0xff;
		arr[3] = capac & 0xff;
	} else {
		arr[0] = 0xff;
		arr[1] = 0xff;
		arr[2] = 0xff;
		arr[3] = 0xff;
	}
	arr[6] = (scsi_debug_sector_size >> 8) & 0xff;
	arr[7] = scsi_debug_sector_size & 0xff;
	return fill_from_dev_buffer(scp, arr, SDEBUG_READCAP_ARR_SZ);
}

#define SDEBUG_READCAP16_ARR_SZ 32
static int resp_readcap16(struct scsi_cmnd * scp,
			  struct sdebug_dev_info * devip)
{
	unsigned char *cmd = scp->cmnd;
	unsigned char arr[SDEBUG_READCAP16_ARR_SZ];
	unsigned long long capac;
	int errsts, k, alloc_len;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	alloc_len = ((cmd[10] << 24) + (cmd[11] << 16) + (cmd[12] << 8)
		     + cmd[13]);
	/* following just in case virtual_gb changed */
	sdebug_capacity = get_sdebug_capacity();
	memset(arr, 0, SDEBUG_READCAP16_ARR_SZ);
	capac = sdebug_capacity - 1;
	for (k = 0; k < 8; ++k, capac >>= 8)
		arr[7 - k] = capac & 0xff;
	arr[8] = (scsi_debug_sector_size >> 24) & 0xff;
	arr[9] = (scsi_debug_sector_size >> 16) & 0xff;
	arr[10] = (scsi_debug_sector_size >> 8) & 0xff;
	arr[11] = scsi_debug_sector_size & 0xff;
	arr[13] = scsi_debug_physblk_exp & 0xf;
	arr[14] = (scsi_debug_lowest_aligned >> 8) & 0x3f;

	if (scsi_debug_lbp()) {
		arr[14] |= 0x80; /* LBPME */
		if (scsi_debug_lbprz)
			arr[14] |= 0x40; /* LBPRZ */
	}

	arr[15] = scsi_debug_lowest_aligned & 0xff;

	if (scsi_debug_dif) {
		arr[12] = (scsi_debug_dif - 1) << 1; /* P_TYPE */
		arr[12] |= 1; /* PROT_EN */
	}

	return fill_from_dev_buffer(scp, arr,
				    min(alloc_len, SDEBUG_READCAP16_ARR_SZ));
}

#define SDEBUG_MAX_TGTPGS_ARR_SZ 1412

static int resp_report_tgtpgs(struct scsi_cmnd * scp,
			      struct sdebug_dev_info * devip)
{
	unsigned char *cmd = scp->cmnd;
	unsigned char * arr;
	int host_no = devip->sdbg_host->shost->host_no;
	int n, ret, alen, rlen;
	int port_group_a, port_group_b, port_a, port_b;

	alen = ((cmd[6] << 24) + (cmd[7] << 16) + (cmd[8] << 8)
		+ cmd[9]);

	arr = kzalloc(SDEBUG_MAX_TGTPGS_ARR_SZ, GFP_ATOMIC);
	if (! arr)
		return DID_REQUEUE << 16;
	/*
	 * EVPD page 0x88 states we have two ports, one
	 * real and a fake port with no device connected.
	 * So we create two port groups with one port each
	 * and set the group with port B to unavailable.
	 */
	port_a = 0x1; /* relative port A */
	port_b = 0x2; /* relative port B */
	port_group_a = (((host_no + 1) & 0x7f) << 8) +
	    (devip->channel & 0x7f);
	port_group_b = (((host_no + 1) & 0x7f) << 8) +
	    (devip->channel & 0x7f) + 0x80;

	/*
	 * The asymmetric access state is cycled according to the host_id.
	 */
	n = 4;
	if (0 == scsi_debug_vpd_use_hostno) {
	    arr[n++] = host_no % 3; /* Asymm access state */
	    arr[n++] = 0x0F; /* claim: all states are supported */
	} else {
	    arr[n++] = 0x0; /* Active/Optimized path */
	    arr[n++] = 0x01; /* claim: only support active/optimized paths */
	}
	arr[n++] = (port_group_a >> 8) & 0xff;
	arr[n++] = port_group_a & 0xff;
	arr[n++] = 0;    /* Reserved */
	arr[n++] = 0;    /* Status code */
	arr[n++] = 0;    /* Vendor unique */
	arr[n++] = 0x1;  /* One port per group */
	arr[n++] = 0;    /* Reserved */
	arr[n++] = 0;    /* Reserved */
	arr[n++] = (port_a >> 8) & 0xff;
	arr[n++] = port_a & 0xff;
	arr[n++] = 3;    /* Port unavailable */
	arr[n++] = 0x08; /* claim: only unavailalbe paths are supported */
	arr[n++] = (port_group_b >> 8) & 0xff;
	arr[n++] = port_group_b & 0xff;
	arr[n++] = 0;    /* Reserved */
	arr[n++] = 0;    /* Status code */
	arr[n++] = 0;    /* Vendor unique */
	arr[n++] = 0x1;  /* One port per group */
	arr[n++] = 0;    /* Reserved */
	arr[n++] = 0;    /* Reserved */
	arr[n++] = (port_b >> 8) & 0xff;
	arr[n++] = port_b & 0xff;

	rlen = n - 4;
	arr[0] = (rlen >> 24) & 0xff;
	arr[1] = (rlen >> 16) & 0xff;
	arr[2] = (rlen >> 8) & 0xff;
	arr[3] = rlen & 0xff;

	/*
	 * Return the smallest value of either
	 * - The allocated length
	 * - The constructed command length
	 * - The maximum array size
	 */
	rlen = min(alen,n);
	ret = fill_from_dev_buffer(scp, arr,
				   min(rlen, SDEBUG_MAX_TGTPGS_ARR_SZ));
	kfree(arr);
	return ret;
}

/* <<Following mode page info copied from ST318451LW>> */

static int resp_err_recov_pg(unsigned char * p, int pcontrol, int target)
{	/* Read-Write Error Recovery page for mode_sense */
	unsigned char err_recov_pg[] = {0x1, 0xa, 0xc0, 11, 240, 0, 0, 0,
					5, 0, 0xff, 0xff};

	memcpy(p, err_recov_pg, sizeof(err_recov_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(err_recov_pg) - 2);
	return sizeof(err_recov_pg);
}

static int resp_disconnect_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Disconnect-Reconnect page for mode_sense */
	unsigned char disconnect_pg[] = {0x2, 0xe, 128, 128, 0, 10, 0, 0,
					 0, 0, 0, 0, 0, 0, 0, 0};

	memcpy(p, disconnect_pg, sizeof(disconnect_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(disconnect_pg) - 2);
	return sizeof(disconnect_pg);
}

static int resp_format_pg(unsigned char * p, int pcontrol, int target)
{       /* Format device page for mode_sense */
	unsigned char format_pg[] = {0x3, 0x16, 0, 0, 0, 0, 0, 0,
				     0, 0, 0, 0, 0, 0, 0, 0,
				     0, 0, 0, 0, 0x40, 0, 0, 0};

	memcpy(p, format_pg, sizeof(format_pg));
	p[10] = (sdebug_sectors_per >> 8) & 0xff;
	p[11] = sdebug_sectors_per & 0xff;
	p[12] = (scsi_debug_sector_size >> 8) & 0xff;
	p[13] = scsi_debug_sector_size & 0xff;
	if (scsi_debug_removable)
		p[20] |= 0x20; /* should agree with INQUIRY */
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(format_pg) - 2);
	return sizeof(format_pg);
}

static int resp_caching_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Caching page for mode_sense */
	unsigned char ch_caching_pg[] = {/* 0x8, 18, */ 0x4, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
	unsigned char d_caching_pg[] = {0x8, 18, 0x14, 0, 0xff, 0xff, 0, 0,
		0xff, 0xff, 0xff, 0xff, 0x80, 0x14, 0, 0,     0, 0, 0, 0};

	if (SCSI_DEBUG_OPT_N_WCE & scsi_debug_opts)
		caching_pg[2] &= ~0x4;	/* set WCE=0 (default WCE=1) */
	memcpy(p, caching_pg, sizeof(caching_pg));
	if (1 == pcontrol)
		memcpy(p + 2, ch_caching_pg, sizeof(ch_caching_pg));
	else if (2 == pcontrol)
		memcpy(p, d_caching_pg, sizeof(d_caching_pg));
	return sizeof(caching_pg);
}

static int resp_ctrl_m_pg(unsigned char * p, int pcontrol, int target)
{ 	/* Control mode page for mode_sense */
	unsigned char ch_ctrl_m_pg[] = {/* 0xa, 10, */ 0x6, 0, 0, 0, 0, 0,
				        0, 0, 0, 0};
	unsigned char d_ctrl_m_pg[] = {0xa, 10, 2, 0, 0, 0, 0, 0,
				     0, 0, 0x2, 0x4b};

	if (scsi_debug_dsense)
		ctrl_m_pg[2] |= 0x4;
	else
		ctrl_m_pg[2] &= ~0x4;

	if (scsi_debug_ato)
		ctrl_m_pg[5] |= 0x80; /* ATO=1 */

	memcpy(p, ctrl_m_pg, sizeof(ctrl_m_pg));
	if (1 == pcontrol)
		memcpy(p + 2, ch_ctrl_m_pg, sizeof(ch_ctrl_m_pg));
	else if (2 == pcontrol)
		memcpy(p, d_ctrl_m_pg, sizeof(d_ctrl_m_pg));
	return sizeof(ctrl_m_pg);
}


static int resp_iec_m_pg(unsigned char * p, int pcontrol, int target)
{	/* Informational Exceptions control mode page for mode_sense */
	unsigned char ch_iec_m_pg[] = {/* 0x1c, 0xa, */ 0x4, 0xf, 0, 0, 0, 0,
				       0, 0, 0x0, 0x0};
	unsigned char d_iec_m_pg[] = {0x1c, 0xa, 0x08, 0, 0, 0, 0, 0,
				      0, 0, 0x0, 0x0};

	memcpy(p, iec_m_pg, sizeof(iec_m_pg));
	if (1 == pcontrol)
		memcpy(p + 2, ch_iec_m_pg, sizeof(ch_iec_m_pg));
	else if (2 == pcontrol)
		memcpy(p, d_iec_m_pg, sizeof(d_iec_m_pg));
	return sizeof(iec_m_pg);
}

static int resp_sas_sf_m_pg(unsigned char * p, int pcontrol, int target)
{	/* SAS SSP mode page - short format for mode_sense */
	unsigned char sas_sf_m_pg[] = {0x19, 0x6,
		0x6, 0x0, 0x7, 0xd0, 0x0, 0x0};

	memcpy(p, sas_sf_m_pg, sizeof(sas_sf_m_pg));
	if (1 == pcontrol)
		memset(p + 2, 0, sizeof(sas_sf_m_pg) - 2);
	return sizeof(sas_sf_m_pg);
}


static int resp_sas_pcd_m_spg(unsigned char * p, int pcontrol, int target,
			      int target_dev_id)
{	/* SAS phy control and discover mode page for mode_sense */
	unsigned char sas_pcd_m_pg[] = {0x59, 0x1, 0, 0x64, 0, 0x6, 0, 2,
		    0, 0, 0, 0, 0x10, 0x9, 0x8, 0x0,
		    0x52, 0x22, 0x22, 0x20, 0x0, 0x0, 0x0, 0x0,
		    0x51, 0x11, 0x11, 0x10, 0x0, 0x0, 0x0, 0x1,
		    0x2, 0, 0, 0, 0, 0, 0, 0,
		    0x88, 0x99, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0,
		    0, 1, 0, 0, 0x10, 0x9, 0x8, 0x0,
		    0x52, 0x22, 0x22, 0x20, 0x0, 0x0, 0x0, 0x0,
		    0x51, 0x11, 0x11, 0x10, 0x0, 0x0, 0x0, 0x1,
		    0x3, 0, 0, 0, 0, 0, 0, 0,
		    0x88, 0x99, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0,
		};
	int port_a, port_b;

	port_a = target_dev_id + 1;
	port_b = port_a + 1;
	memcpy(p, sas_pcd_m_pg, sizeof(sas_pcd_m_pg));
	p[20] = (port_a >> 24);
	p[21] = (port_a >> 16) & 0xff;
	p[22] = (port_a >> 8) & 0xff;
	p[23] = port_a & 0xff;
	p[48 + 20] = (port_b >> 24);
	p[48 + 21] = (port_b >> 16) & 0xff;
	p[48 + 22] = (port_b >> 8) & 0xff;
	p[48 + 23] = port_b & 0xff;
	if (1 == pcontrol)
		memset(p + 4, 0, sizeof(sas_pcd_m_pg) - 4);
	return sizeof(sas_pcd_m_pg);
}

static int resp_sas_sha_m_spg(unsigned char * p, int pcontrol)
{	/* SAS SSP shared protocol specific port mode subpage */
	unsigned char sas_sha_m_pg[] = {0x59, 0x2, 0, 0xc, 0, 0x6, 0x10, 0,
		    0, 0, 0, 0, 0, 0, 0, 0,
		};

	memcpy(p, sas_sha_m_pg, sizeof(sas_sha_m_pg));
	if (1 == pcontrol)
		memset(p + 4, 0, sizeof(sas_sha_m_pg) - 4);
	return sizeof(sas_sha_m_pg);
}

#define SDEBUG_MAX_MSENSE_SZ 256

static int resp_mode_sense(struct scsi_cmnd * scp, int target,
			   struct sdebug_dev_info * devip)
{
	unsigned char dbd, llbaa;
	int pcontrol, pcode, subpcode, bd_len;
	unsigned char dev_spec;
	int k, alloc_len, msense_6, offset, len, errsts, target_dev_id;
	unsigned char * ap;
	unsigned char arr[SDEBUG_MAX_MSENSE_SZ];
	unsigned char *cmd = scp->cmnd;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	dbd = !!(cmd[1] & 0x8);
	pcontrol = (cmd[2] & 0xc0) >> 6;
	pcode = cmd[2] & 0x3f;
	subpcode = cmd[3];
	msense_6 = (MODE_SENSE == cmd[0]);
	llbaa = msense_6 ? 0 : !!(cmd[1] & 0x10);
	if ((0 == scsi_debug_ptype) && (0 == dbd))
		bd_len = llbaa ? 16 : 8;
	else
		bd_len = 0;
	alloc_len = msense_6 ? cmd[4] : ((cmd[7] << 8) | cmd[8]);
	memset(arr, 0, SDEBUG_MAX_MSENSE_SZ);
	if (0x3 == pcontrol) {  /* Saving values not supported */
		mk_sense_buffer(scp, ILLEGAL_REQUEST, SAVING_PARAMS_UNSUP, 0);
		return check_condition_result;
	}
	target_dev_id = ((devip->sdbg_host->shost->host_no + 1) * 2000) +
			(devip->target * 1000) - 3;
	/* set DPOFUA bit for disks */
	if (0 == scsi_debug_ptype)
		dev_spec = (DEV_READONLY(target) ? 0x80 : 0x0) | 0x10;
	else
		dev_spec = 0x0;
	if (msense_6) {
		arr[2] = dev_spec;
		arr[3] = bd_len;
		offset = 4;
	} else {
		arr[3] = dev_spec;
		if (16 == bd_len)
			arr[4] = 0x1;	/* set LONGLBA bit */
		arr[7] = bd_len;	/* assume 255 or less */
		offset = 8;
	}
	ap = arr + offset;
	if ((bd_len > 0) && (!sdebug_capacity))
		sdebug_capacity = get_sdebug_capacity();

	if (8 == bd_len) {
		if (sdebug_capacity > 0xfffffffe) {
			ap[0] = 0xff;
			ap[1] = 0xff;
			ap[2] = 0xff;
			ap[3] = 0xff;
		} else {
			ap[0] = (sdebug_capacity >> 24) & 0xff;
			ap[1] = (sdebug_capacity >> 16) & 0xff;
			ap[2] = (sdebug_capacity >> 8) & 0xff;
			ap[3] = sdebug_capacity & 0xff;
		}
		ap[6] = (scsi_debug_sector_size >> 8) & 0xff;
		ap[7] = scsi_debug_sector_size & 0xff;
		offset += bd_len;
		ap = arr + offset;
	} else if (16 == bd_len) {
		unsigned long long capac = sdebug_capacity;

        	for (k = 0; k < 8; ++k, capac >>= 8)
                	ap[7 - k] = capac & 0xff;
		ap[12] = (scsi_debug_sector_size >> 24) & 0xff;
		ap[13] = (scsi_debug_sector_size >> 16) & 0xff;
		ap[14] = (scsi_debug_sector_size >> 8) & 0xff;
		ap[15] = scsi_debug_sector_size & 0xff;
		offset += bd_len;
		ap = arr + offset;
	}

	if ((subpcode > 0x0) && (subpcode < 0xff) && (0x19 != pcode)) {
		/* TODO: Control Extension page */
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	switch (pcode) {
	case 0x1:	/* Read-Write error recovery page, direct access */
		len = resp_err_recov_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x2:	/* Disconnect-Reconnect page, all devices */
		len = resp_disconnect_pg(ap, pcontrol, target);
		offset += len;
		break;
        case 0x3:       /* Format device page, direct access */
                len = resp_format_pg(ap, pcontrol, target);
                offset += len;
                break;
	case 0x8:	/* Caching page, direct access */
		len = resp_caching_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0xa:	/* Control Mode page, all devices */
		len = resp_ctrl_m_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x19:	/* if spc==1 then sas phy, control+discover */
		if ((subpcode > 0x2) && (subpcode < 0xff)) {
			mk_sense_buffer(scp, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			return check_condition_result;
	        }
		len = 0;
		if ((0x0 == subpcode) || (0xff == subpcode))
			len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
		if ((0x1 == subpcode) || (0xff == subpcode))
			len += resp_sas_pcd_m_spg(ap + len, pcontrol, target,
						  target_dev_id);
		if ((0x2 == subpcode) || (0xff == subpcode))
			len += resp_sas_sha_m_spg(ap + len, pcontrol);
		offset += len;
		break;
	case 0x1c:	/* Informational Exceptions Mode page, all devices */
		len = resp_iec_m_pg(ap, pcontrol, target);
		offset += len;
		break;
	case 0x3f:	/* Read all Mode pages */
		if ((0 == subpcode) || (0xff == subpcode)) {
			len = resp_err_recov_pg(ap, pcontrol, target);
			len += resp_disconnect_pg(ap + len, pcontrol, target);
			len += resp_format_pg(ap + len, pcontrol, target);
			len += resp_caching_pg(ap + len, pcontrol, target);
			len += resp_ctrl_m_pg(ap + len, pcontrol, target);
			len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
			if (0xff == subpcode) {
				len += resp_sas_pcd_m_spg(ap + len, pcontrol,
						  target, target_dev_id);
				len += resp_sas_sha_m_spg(ap + len, pcontrol);
			}
			len += resp_iec_m_pg(ap + len, pcontrol, target);
		} else {
			mk_sense_buffer(scp, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			return check_condition_result;
                }
		offset += len;
		break;
	default:
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	if (msense_6)
		arr[0] = offset - 1;
	else {
		arr[0] = ((offset - 2) >> 8) & 0xff;
		arr[1] = (offset - 2) & 0xff;
	}
	return fill_from_dev_buffer(scp, arr, min(alloc_len, offset));
}

#define SDEBUG_MAX_MSELECT_SZ 512

static int resp_mode_select(struct scsi_cmnd * scp, int mselect6,
			    struct sdebug_dev_info * devip)
{
	int pf, sp, ps, md_len, bd_len, off, spf, pg_len;
	int param_len, res, errsts, mpage;
	unsigned char arr[SDEBUG_MAX_MSELECT_SZ];
	unsigned char *cmd = scp->cmnd;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	memset(arr, 0, sizeof(arr));
	pf = cmd[1] & 0x10;
	sp = cmd[1] & 0x1;
	param_len = mselect6 ? cmd[4] : ((cmd[7] << 8) + cmd[8]);
	if ((0 == pf) || sp || (param_len > SDEBUG_MAX_MSELECT_SZ)) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_CDB, 0);
		return check_condition_result;
	}
        res = fetch_to_dev_buffer(scp, arr, param_len);
        if (-1 == res)
                return (DID_ERROR << 16);
        else if ((res < param_len) &&
                 (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
		sdev_printk(KERN_INFO, scp->device,
			    "%s: cdb indicated=%d, IO sent=%d bytes\n",
			    __func__, param_len, res);
	md_len = mselect6 ? (arr[0] + 1) : ((arr[0] << 8) + arr[1] + 2);
	bd_len = mselect6 ? arr[3] : ((arr[6] << 8) + arr[7]);
	if (md_len > 2) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_PARAM_LIST, 0);
		return check_condition_result;
	}
	off = bd_len + (mselect6 ? 4 : 8);
	mpage = arr[off] & 0x3f;
	ps = !!(arr[off] & 0x80);
	if (ps) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_PARAM_LIST, 0);
		return check_condition_result;
	}
	spf = !!(arr[off] & 0x40);
	pg_len = spf ? ((arr[off + 2] << 8) + arr[off + 3] + 4) :
		       (arr[off + 1] + 2);
	if ((pg_len + off) > param_len) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				PARAMETER_LIST_LENGTH_ERR, 0);
		return check_condition_result;
	}
	switch (mpage) {
	case 0x8:      /* Caching Mode page */
		if (caching_pg[1] == arr[off + 1]) {
			memcpy(caching_pg + 2, arr + off + 2,
			       sizeof(caching_pg) - 2);
			goto set_mode_changed_ua;
		}
		break;
	case 0xa:      /* Control Mode page */
		if (ctrl_m_pg[1] == arr[off + 1]) {
			memcpy(ctrl_m_pg + 2, arr + off + 2,
			       sizeof(ctrl_m_pg) - 2);
			scsi_debug_dsense = !!(ctrl_m_pg[2] & 0x4);
			goto set_mode_changed_ua;
		}
		break;
	case 0x1c:      /* Informational Exceptions Mode page */
		if (iec_m_pg[1] == arr[off + 1]) {
			memcpy(iec_m_pg + 2, arr + off + 2,
			       sizeof(iec_m_pg) - 2);
			goto set_mode_changed_ua;
		}
		break;
	default:
		break;
	}
	mk_sense_buffer(scp, ILLEGAL_REQUEST,
			INVALID_FIELD_IN_PARAM_LIST, 0);
	return check_condition_result;
set_mode_changed_ua:
	set_bit(SDEBUG_UA_MODE_CHANGED, devip->uas_bm);
	return 0;
}

static int resp_temp_l_pg(unsigned char * arr)
{
	unsigned char temp_l_pg[] = {0x0, 0x0, 0x3, 0x2, 0x0, 38,
				     0x0, 0x1, 0x3, 0x2, 0x0, 65,
		};

        memcpy(arr, temp_l_pg, sizeof(temp_l_pg));
        return sizeof(temp_l_pg);
}

static int resp_ie_l_pg(unsigned char * arr)
{
	unsigned char ie_l_pg[] = {0x0, 0x0, 0x3, 0x3, 0x0, 0x0, 38,
		};

        memcpy(arr, ie_l_pg, sizeof(ie_l_pg));
	if (iec_m_pg[2] & 0x4) {	/* TEST bit set */
		arr[4] = THRESHOLD_EXCEEDED;
		arr[5] = 0xff;
	}
        return sizeof(ie_l_pg);
}

#define SDEBUG_MAX_LSENSE_SZ 512

static int resp_log_sense(struct scsi_cmnd * scp,
                          struct sdebug_dev_info * devip)
{
	int ppc, sp, pcontrol, pcode, subpcode, alloc_len, errsts, len, n;
	unsigned char arr[SDEBUG_MAX_LSENSE_SZ];
	unsigned char *cmd = scp->cmnd;

	errsts = check_readiness(scp, UAS_ONLY, devip);
	if (errsts)
		return errsts;
	memset(arr, 0, sizeof(arr));
	ppc = cmd[1] & 0x2;
	sp = cmd[1] & 0x1;
	if (ppc || sp) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_CDB, 0);
		return check_condition_result;
	}
	pcontrol = (cmd[2] & 0xc0) >> 6;
	pcode = cmd[2] & 0x3f;
	subpcode = cmd[3] & 0xff;
	alloc_len = (cmd[7] << 8) + cmd[8];
	arr[0] = pcode;
	if (0 == subpcode) {
		switch (pcode) {
		case 0x0:	/* Supported log pages log page */
			n = 4;
			arr[n++] = 0x0;		/* this page */
			arr[n++] = 0xd;		/* Temperature */
			arr[n++] = 0x2f;	/* Informational exceptions */
			arr[3] = n - 4;
			break;
		case 0xd:	/* Temperature log page */
			arr[3] = resp_temp_l_pg(arr + 4);
			break;
		case 0x2f:	/* Informational exceptions log page */
			arr[3] = resp_ie_l_pg(arr + 4);
			break;
		default:
			mk_sense_buffer(scp, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			return check_condition_result;
		}
	} else if (0xff == subpcode) {
		arr[0] |= 0x40;
		arr[1] = subpcode;
		switch (pcode) {
		case 0x0:	/* Supported log pages and subpages log page */
			n = 4;
			arr[n++] = 0x0;
			arr[n++] = 0x0;		/* 0,0 page */
			arr[n++] = 0x0;
			arr[n++] = 0xff;	/* this page */
			arr[n++] = 0xd;
			arr[n++] = 0x0;		/* Temperature */
			arr[n++] = 0x2f;
			arr[n++] = 0x0;	/* Informational exceptions */
			arr[3] = n - 4;
			break;
		case 0xd:	/* Temperature subpages */
			n = 4;
			arr[n++] = 0xd;
			arr[n++] = 0x0;		/* Temperature */
			arr[3] = n - 4;
			break;
		case 0x2f:	/* Informational exceptions subpages */
			n = 4;
			arr[n++] = 0x2f;
			arr[n++] = 0x0;		/* Informational exceptions */
			arr[3] = n - 4;
			break;
		default:
			mk_sense_buffer(scp, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			return check_condition_result;
		}
	} else {
		mk_sense_buffer(scp, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_CDB, 0);
		return check_condition_result;
	}
	len = min(((arr[2] << 8) + arr[3]) + 4, alloc_len);
	return fill_from_dev_buffer(scp, arr,
		    min(len, SDEBUG_MAX_INQ_ARR_SZ));
}

static int check_device_access_params(struct scsi_cmnd *scp,
				      unsigned long long lba, unsigned int num)
{
	if (lba + num > sdebug_capacity) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST, ADDR_OUT_OF_RANGE, 0);
		return check_condition_result;
	}
	/* transfer length excessive (tie in to block limits VPD page) */
	if (num > sdebug_store_sectors) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
		return check_condition_result;
	}
	return 0;
}

/* Returns number of bytes copied or -1 if error. */
static int do_device_access(struct scsi_cmnd *scmd,
			    unsigned long long lba, unsigned int num, int write)
{
	int ret;
	unsigned long long block, rest = 0;
	struct scsi_data_buffer *sdb;
	enum dma_data_direction dir;
	size_t (*func)(struct scatterlist *, unsigned int, void *, size_t,
		       off_t);

	if (write) {
		sdb = scsi_out(scmd);
		dir = DMA_TO_DEVICE;
		func = sg_pcopy_to_buffer;
	} else {
		sdb = scsi_in(scmd);
		dir = DMA_FROM_DEVICE;
		func = sg_pcopy_from_buffer;
	}

	if (!sdb->length)
		return 0;
	if (!(scsi_bidi_cmnd(scmd) || scmd->sc_data_direction == dir))
		return -1;

	block = do_div(lba, sdebug_store_sectors);
	if (block + num > sdebug_store_sectors)
		rest = block + num - sdebug_store_sectors;

	ret = func(sdb->table.sgl, sdb->table.nents,
		   fake_storep + (block * scsi_debug_sector_size),
		   (num - rest) * scsi_debug_sector_size, 0);
	if (ret != (num - rest) * scsi_debug_sector_size)
		return ret;

	if (rest) {
		ret += func(sdb->table.sgl, sdb->table.nents,
			    fake_storep, rest * scsi_debug_sector_size,
			    (num - rest) * scsi_debug_sector_size);
	}

	return ret;
}

static __be16 dif_compute_csum(const void *buf, int len)
{
	__be16 csum;

	if (scsi_debug_guard)
		csum = (__force __be16)ip_compute_csum(buf, len);
	else
		csum = cpu_to_be16(crc_t10dif(buf, len));

	return csum;
}

static int dif_verify(struct sd_dif_tuple *sdt, const void *data,
		      sector_t sector, u32 ei_lba)
{
	__be16 csum = dif_compute_csum(data, scsi_debug_sector_size);

	if (sdt->guard_tag != csum) {
		pr_err("%s: GUARD check failed on sector %lu rcvd 0x%04x, data 0x%04x\n",
			__func__,
			(unsigned long)sector,
			be16_to_cpu(sdt->guard_tag),
			be16_to_cpu(csum));
		return 0x01;
	}
	if (scsi_debug_dif == SD_DIF_TYPE1_PROTECTION &&
	    be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
		pr_err("%s: REF check failed on sector %lu\n",
			__func__, (unsigned long)sector);
		return 0x03;
	}
	if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
	    be32_to_cpu(sdt->ref_tag) != ei_lba) {
		pr_err("%s: REF check failed on sector %lu\n",
			__func__, (unsigned long)sector);
		return 0x03;
	}
	return 0;
}

static void dif_copy_prot(struct scsi_cmnd *SCpnt, sector_t sector,
			  unsigned int sectors, bool read)
{
	size_t resid;
	void *paddr;
	const void *dif_store_end = dif_storep + sdebug_store_sectors;
	struct sg_mapping_iter miter;

	/* Bytes of protection data to copy into sgl */
	resid = sectors * sizeof(*dif_storep);

	sg_miter_start(&miter, scsi_prot_sglist(SCpnt),
			scsi_prot_sg_count(SCpnt), SG_MITER_ATOMIC |
			(read ? SG_MITER_TO_SG : SG_MITER_FROM_SG));

	while (sg_miter_next(&miter) && resid > 0) {
		size_t len = min(miter.length, resid);
		void *start = dif_store(sector);
		size_t rest = 0;

		if (dif_store_end < start + len)
			rest = start + len - dif_store_end;

		paddr = miter.addr;

		if (read)
			memcpy(paddr, start, len - rest);
		else
			memcpy(start, paddr, len - rest);

		if (rest) {
			if (read)
				memcpy(paddr + len - rest, dif_storep, rest);
			else
				memcpy(dif_storep, paddr + len - rest, rest);
		}

		sector += len / sizeof(*dif_storep);
		resid -= len;
	}
	sg_miter_stop(&miter);
}

static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
			    unsigned int sectors, u32 ei_lba)
{
	unsigned int i;
	struct sd_dif_tuple *sdt;
	sector_t sector;

	for (i = 0; i < sectors; i++, ei_lba++) {
		int ret;

		sector = start_sec + i;
		sdt = dif_store(sector);

		if (sdt->app_tag == cpu_to_be16(0xffff))
			continue;

		ret = dif_verify(sdt, fake_store(sector), sector, ei_lba);
		if (ret) {
			dif_errors++;
			return ret;
		}
	}

	dif_copy_prot(SCpnt, start_sec, sectors, true);
	dix_reads++;

	return 0;
}

static int resp_read(struct scsi_cmnd *SCpnt, unsigned long long lba,
		     unsigned int num, u32 ei_lba)
{
	unsigned long iflags;
	int ret;

	ret = check_device_access_params(SCpnt, lba, num);
	if (ret)
		return ret;

	if ((SCSI_DEBUG_OPT_MEDIUM_ERR & scsi_debug_opts) &&
	    (lba <= (OPT_MEDIUM_ERR_ADDR + OPT_MEDIUM_ERR_NUM - 1)) &&
	    ((lba + num) > OPT_MEDIUM_ERR_ADDR)) {
		/* claim unrecoverable read error */
		mk_sense_buffer(SCpnt, MEDIUM_ERROR, UNRECOVERED_READ_ERR, 0);
		/* set info field and valid bit for fixed descriptor */
		if (0x70 == (SCpnt->sense_buffer[0] & 0x7f)) {
			SCpnt->sense_buffer[0] |= 0x80;	/* Valid bit */
			ret = (lba < OPT_MEDIUM_ERR_ADDR)
			      ? OPT_MEDIUM_ERR_ADDR : (int)lba;
			SCpnt->sense_buffer[3] = (ret >> 24) & 0xff;
			SCpnt->sense_buffer[4] = (ret >> 16) & 0xff;
			SCpnt->sense_buffer[5] = (ret >> 8) & 0xff;
			SCpnt->sense_buffer[6] = ret & 0xff;
		}
	        scsi_set_resid(SCpnt, scsi_bufflen(SCpnt));
		return check_condition_result;
	}

	read_lock_irqsave(&atomic_rw, iflags);

	/* DIX + T10 DIF */
	if (scsi_debug_dix && scsi_prot_sg_count(SCpnt)) {
		int prot_ret = prot_verify_read(SCpnt, lba, num, ei_lba);

		if (prot_ret) {
			read_unlock_irqrestore(&atomic_rw, iflags);
			mk_sense_buffer(SCpnt, ABORTED_COMMAND, 0x10, prot_ret);
			return illegal_condition_result;
		}
	}

	ret = do_device_access(SCpnt, lba, num, 0);
	read_unlock_irqrestore(&atomic_rw, iflags);
	if (ret == -1)
		return DID_ERROR << 16;

	scsi_in(SCpnt)->resid = scsi_bufflen(SCpnt) - ret;

	return 0;
}

void dump_sector(unsigned char *buf, int len)
{
	int i, j, n;

	pr_err(">>> Sector Dump <<<\n");
	for (i = 0 ; i < len ; i += 16) {
		char b[128];

		for (j = 0, n = 0; j < 16; j++) {
			unsigned char c = buf[i+j];

			if (c >= 0x20 && c < 0x7e)
				n += scnprintf(b + n, sizeof(b) - n,
					       " %c ", buf[i+j]);
			else
				n += scnprintf(b + n, sizeof(b) - n,
					       "%02x ", buf[i+j]);
		}
		pr_err("%04d: %s\n", i, b);
	}
}

static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec,
			     unsigned int sectors, u32 ei_lba)
{
	int ret;
	struct sd_dif_tuple *sdt;
	void *daddr;
	sector_t sector = start_sec;
	int ppage_offset;
	int dpage_offset;
	struct sg_mapping_iter diter;
	struct sg_mapping_iter piter;

	BUG_ON(scsi_sg_count(SCpnt) == 0);
	BUG_ON(scsi_prot_sg_count(SCpnt) == 0);

	sg_miter_start(&piter, scsi_prot_sglist(SCpnt),
			scsi_prot_sg_count(SCpnt),
			SG_MITER_ATOMIC | SG_MITER_FROM_SG);
	sg_miter_start(&diter, scsi_sglist(SCpnt), scsi_sg_count(SCpnt),
			SG_MITER_ATOMIC | SG_MITER_FROM_SG);

	/* For each protection page */
	while (sg_miter_next(&piter)) {
		dpage_offset = 0;
		if (WARN_ON(!sg_miter_next(&diter))) {
			ret = 0x01;
			goto out;
		}

		for (ppage_offset = 0; ppage_offset < piter.length;
		     ppage_offset += sizeof(struct sd_dif_tuple)) {
			/* If we're at the end of the current
			 * data page advance to the next one
			 */
			if (dpage_offset >= diter.length) {
				if (WARN_ON(!sg_miter_next(&diter))) {
					ret = 0x01;
					goto out;
				}
				dpage_offset = 0;
			}

			sdt = piter.addr + ppage_offset;
			daddr = diter.addr + dpage_offset;

			ret = dif_verify(sdt, daddr, sector, ei_lba);
			if (ret) {
				dump_sector(daddr, scsi_debug_sector_size);
				goto out;
			}

			sector++;
			ei_lba++;
			dpage_offset += scsi_debug_sector_size;
		}
		diter.consumed = dpage_offset;
		sg_miter_stop(&diter);
	}
	sg_miter_stop(&piter);

	dif_copy_prot(SCpnt, start_sec, sectors, false);
	dix_writes++;

	return 0;

out:
	dif_errors++;
	sg_miter_stop(&diter);
	sg_miter_stop(&piter);
	return ret;
}

static unsigned long lba_to_map_index(sector_t lba)
{
	if (scsi_debug_unmap_alignment) {
		lba += scsi_debug_unmap_granularity -
			scsi_debug_unmap_alignment;
	}
	do_div(lba, scsi_debug_unmap_granularity);

	return lba;
}

static sector_t map_index_to_lba(unsigned long index)
{
	sector_t lba = index * scsi_debug_unmap_granularity;

	if (scsi_debug_unmap_alignment) {
		lba -= scsi_debug_unmap_granularity -
			scsi_debug_unmap_alignment;
	}

	return lba;
}

static unsigned int map_state(sector_t lba, unsigned int *num)
{
	sector_t end;
	unsigned int mapped;
	unsigned long index;
	unsigned long next;

	index = lba_to_map_index(lba);
	mapped = test_bit(index, map_storep);

	if (mapped)
		next = find_next_zero_bit(map_storep, map_size, index);
	else
		next = find_next_bit(map_storep, map_size, index);

	end = min_t(sector_t, sdebug_store_sectors,  map_index_to_lba(next));
	*num = end - lba;

	return mapped;
}

static void map_region(sector_t lba, unsigned int len)
{
	sector_t end = lba + len;

	while (lba < end) {
		unsigned long index = lba_to_map_index(lba);

		if (index < map_size)
			set_bit(index, map_storep);

		lba = map_index_to_lba(index + 1);
	}
}

static void unmap_region(sector_t lba, unsigned int len)
{
	sector_t end = lba + len;

	while (lba < end) {
		unsigned long index = lba_to_map_index(lba);

		if (lba == map_index_to_lba(index) &&
		    lba + scsi_debug_unmap_granularity <= end &&
		    index < map_size) {
			clear_bit(index, map_storep);
			if (scsi_debug_lbprz) {
				memset(fake_storep +
				       lba * scsi_debug_sector_size, 0,
				       scsi_debug_sector_size *
				       scsi_debug_unmap_granularity);
			}
			if (dif_storep) {
				memset(dif_storep + lba, 0xff,
				       sizeof(*dif_storep) *
				       scsi_debug_unmap_granularity);
			}
		}
		lba = map_index_to_lba(index + 1);
	}
}

static int resp_write(struct scsi_cmnd *SCpnt, unsigned long long lba,
		      unsigned int num, u32 ei_lba)
{
	unsigned long iflags;
	int ret;

	ret = check_device_access_params(SCpnt, lba, num);
	if (ret)
		return ret;

	write_lock_irqsave(&atomic_rw, iflags);

	/* DIX + T10 DIF */
	if (scsi_debug_dix && scsi_prot_sg_count(SCpnt)) {
		int prot_ret = prot_verify_write(SCpnt, lba, num, ei_lba);

		if (prot_ret) {
			write_unlock_irqrestore(&atomic_rw, iflags);
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST, 0x10,
					prot_ret);
			return illegal_condition_result;
		}
	}

	ret = do_device_access(SCpnt, lba, num, 1);
	if (scsi_debug_lbp())
		map_region(lba, num);
	write_unlock_irqrestore(&atomic_rw, iflags);
	if (-1 == ret)
		return (DID_ERROR << 16);
	else if ((ret < (num * scsi_debug_sector_size)) &&
		 (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
		sdev_printk(KERN_INFO, SCpnt->device,
			    "%s: write: cdb indicated=%u, IO sent=%d bytes\n",
			    my_name, num * scsi_debug_sector_size, ret);

	return 0;
}

static int resp_write_same(struct scsi_cmnd *scmd, unsigned long long lba,
		      unsigned int num, u32 ei_lba, unsigned int unmap)
{
	unsigned long iflags;
	unsigned long long i;
	int ret;

	ret = check_device_access_params(scmd, lba, num);
	if (ret)
		return ret;

	if (num > scsi_debug_write_same_length) {
		mk_sense_buffer(scmd, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
				0);
		return check_condition_result;
	}

	write_lock_irqsave(&atomic_rw, iflags);

	if (unmap && scsi_debug_lbp()) {
		unmap_region(lba, num);
		goto out;
	}

	/* Else fetch one logical block */
	ret = fetch_to_dev_buffer(scmd,
				  fake_storep + (lba * scsi_debug_sector_size),
				  scsi_debug_sector_size);

	if (-1 == ret) {
		write_unlock_irqrestore(&atomic_rw, iflags);
		return (DID_ERROR << 16);
	} else if ((ret < (num * scsi_debug_sector_size)) &&
		 (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
		sdev_printk(KERN_INFO, scmd->device,
			    "%s: %s: cdb indicated=%u, IO sent=%d bytes\n",
			    my_name, "write same",
			    num * scsi_debug_sector_size, ret);

	/* Copy first sector to remaining blocks */
	for (i = 1 ; i < num ; i++)
		memcpy(fake_storep + ((lba + i) * scsi_debug_sector_size),
		       fake_storep + (lba * scsi_debug_sector_size),
		       scsi_debug_sector_size);

	if (scsi_debug_lbp())
		map_region(lba, num);
out:
	write_unlock_irqrestore(&atomic_rw, iflags);

	return 0;
}

struct unmap_block_desc {
	__be64	lba;
	__be32	blocks;
	__be32	__reserved;
};

static int resp_unmap(struct scsi_cmnd * scmd, struct sdebug_dev_info * devip)
{
	unsigned char *buf;
	struct unmap_block_desc *desc;
	unsigned int i, payload_len, descriptors;
	int ret;
	unsigned long iflags;

	ret = check_readiness(scmd, UAS_ONLY, devip);
	if (ret)
		return ret;

	payload_len = get_unaligned_be16(&scmd->cmnd[7]);
	BUG_ON(scsi_bufflen(scmd) != payload_len);

	descriptors = (payload_len - 8) / 16;

	buf = kmalloc(scsi_bufflen(scmd), GFP_ATOMIC);
	if (!buf)
		return check_condition_result;

	scsi_sg_copy_to_buffer(scmd, buf, scsi_bufflen(scmd));

	BUG_ON(get_unaligned_be16(&buf[0]) != payload_len - 2);
	BUG_ON(get_unaligned_be16(&buf[2]) != descriptors * 16);

	desc = (void *)&buf[8];

	write_lock_irqsave(&atomic_rw, iflags);

	for (i = 0 ; i < descriptors ; i++) {
		unsigned long long lba = get_unaligned_be64(&desc[i].lba);
		unsigned int num = get_unaligned_be32(&desc[i].blocks);

		ret = check_device_access_params(scmd, lba, num);
		if (ret)
			goto out;

		unmap_region(lba, num);
	}

	ret = 0;

out:
	write_unlock_irqrestore(&atomic_rw, iflags);
	kfree(buf);

	return ret;
}

#define SDEBUG_GET_LBA_STATUS_LEN 32

static int resp_get_lba_status(struct scsi_cmnd * scmd,
			       struct sdebug_dev_info * devip)
{
	unsigned long long lba;
	unsigned int alloc_len, mapped, num;
	unsigned char arr[SDEBUG_GET_LBA_STATUS_LEN];
	int ret;

	ret = check_readiness(scmd, UAS_ONLY, devip);
	if (ret)
		return ret;

	lba = get_unaligned_be64(&scmd->cmnd[2]);
	alloc_len = get_unaligned_be32(&scmd->cmnd[10]);

	if (alloc_len < 24)
		return 0;

	ret = check_device_access_params(scmd, lba, 1);
	if (ret)
		return ret;

	mapped = map_state(lba, &num);

	memset(arr, 0, SDEBUG_GET_LBA_STATUS_LEN);
	put_unaligned_be32(20, &arr[0]);	/* Parameter Data Length */
	put_unaligned_be64(lba, &arr[8]);	/* LBA */
	put_unaligned_be32(num, &arr[16]);	/* Number of blocks */
	arr[20] = !mapped;			/* mapped = 0, unmapped = 1 */

	return fill_from_dev_buffer(scmd, arr, SDEBUG_GET_LBA_STATUS_LEN);
}

#define SDEBUG_RLUN_ARR_SZ 256

static int resp_report_luns(struct scsi_cmnd * scp,
			    struct sdebug_dev_info * devip)
{
	unsigned int alloc_len;
	int lun_cnt, i, upper, num, n;
	u64 wlun, lun;
	unsigned char *cmd = scp->cmnd;
	int select_report = (int)cmd[2];
	struct scsi_lun *one_lun;
	unsigned char arr[SDEBUG_RLUN_ARR_SZ];
	unsigned char * max_addr;

	alloc_len = cmd[9] + (cmd[8] << 8) + (cmd[7] << 16) + (cmd[6] << 24);
	if ((alloc_len < 4) || (select_report > 2)) {
		mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
			       	0);
		return check_condition_result;
	}
	/* can produce response with up to 16k luns (lun 0 to lun 16383) */
	memset(arr, 0, SDEBUG_RLUN_ARR_SZ);
	lun_cnt = scsi_debug_max_luns;
	if (1 == select_report)
		lun_cnt = 0;
	else if (scsi_debug_no_lun_0 && (lun_cnt > 0))
		--lun_cnt;
	wlun = (select_report > 0) ? 1 : 0;
	num = lun_cnt + wlun;
	arr[2] = ((sizeof(struct scsi_lun) * num) >> 8) & 0xff;
	arr[3] = (sizeof(struct scsi_lun) * num) & 0xff;
	n = min((int)((SDEBUG_RLUN_ARR_SZ - 8) /
			    sizeof(struct scsi_lun)), num);
	if (n < num) {
		wlun = 0;
		lun_cnt = n;
	}
	one_lun = (struct scsi_lun *) &arr[8];
	max_addr = arr + SDEBUG_RLUN_ARR_SZ;
	for (i = 0, lun = (scsi_debug_no_lun_0 ? 1 : 0);
             ((i < lun_cnt) && ((unsigned char *)(one_lun + i) < max_addr));
	     i++, lun++) {
		upper = (lun >> 8) & 0x3f;
		if (upper)
			one_lun[i].scsi_lun[0] =
			    (upper | (SAM2_LUN_ADDRESS_METHOD << 6));
		one_lun[i].scsi_lun[1] = lun & 0xff;
	}
	if (wlun) {
		one_lun[i].scsi_lun[0] = (SAM2_WLUN_REPORT_LUNS >> 8) & 0xff;
		one_lun[i].scsi_lun[1] = SAM2_WLUN_REPORT_LUNS & 0xff;
		i++;
	}
	alloc_len = (unsigned char *)(one_lun + i) - arr;
	return fill_from_dev_buffer(scp, arr,
				    min((int)alloc_len, SDEBUG_RLUN_ARR_SZ));
}

static int resp_xdwriteread(struct scsi_cmnd *scp, unsigned long long lba,
			    unsigned int num, struct sdebug_dev_info *devip)
{
	int j;
	unsigned char *kaddr, *buf;
	unsigned int offset;
	struct scsi_data_buffer *sdb = scsi_in(scp);
	struct sg_mapping_iter miter;

	/* better not to use temporary buffer. */
	buf = kmalloc(scsi_bufflen(scp), GFP_ATOMIC);
	if (!buf) {
		mk_sense_buffer(scp, NOT_READY,
				LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
		return check_condition_result;
	}

	scsi_sg_copy_to_buffer(scp, buf, scsi_bufflen(scp));

	offset = 0;
	sg_miter_start(&miter, sdb->table.sgl, sdb->table.nents,
			SG_MITER_ATOMIC | SG_MITER_TO_SG);

	while (sg_miter_next(&miter)) {
		kaddr = miter.addr;
		for (j = 0; j < miter.length; j++)
			*(kaddr + j) ^= *(buf + offset + j);

		offset += miter.length;
	}
	sg_miter_stop(&miter);
	kfree(buf);

	return 0;
}

/* When timer or tasklet goes off this function is called. */
static void sdebug_q_cmd_complete(unsigned long indx)
{
	int qa_indx;
	int retiring = 0;
	unsigned long iflags;
	struct sdebug_queued_cmd *sqcp;
	struct scsi_cmnd *scp;
	struct sdebug_dev_info *devip;

	atomic_inc(&sdebug_completions);
	qa_indx = indx;
	if ((qa_indx < 0) || (qa_indx >= SCSI_DEBUG_CANQUEUE)) {
		pr_err("%s: wild qa_indx=%d\n", __func__, qa_indx);
		return;
	}
	spin_lock_irqsave(&queued_arr_lock, iflags);
	sqcp = &queued_arr[qa_indx];
	scp = sqcp->a_cmnd;
	if (NULL == scp) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		pr_err("%s: scp is NULL\n", __func__);
		return;
	}
	devip = (struct sdebug_dev_info *)scp->device->hostdata;
	if (devip)
		atomic_dec(&devip->num_in_q);
	else
		pr_err("%s: devip=NULL\n", __func__);
	if (atomic_read(&retired_max_queue) > 0)
		retiring = 1;

	sqcp->a_cmnd = NULL;
	if (!test_and_clear_bit(qa_indx, queued_in_use_bm)) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		pr_err("%s: Unexpected completion\n", __func__);
		return;
	}

	if (unlikely(retiring)) {	/* user has reduced max_queue */
		int k, retval;

		retval = atomic_read(&retired_max_queue);
		if (qa_indx >= retval) {
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
			pr_err("%s: index %d too large\n", __func__, retval);
			return;
		}
		k = find_last_bit(queued_in_use_bm, retval);
		if ((k < scsi_debug_max_queue) || (k == retval))
			atomic_set(&retired_max_queue, 0);
		else
			atomic_set(&retired_max_queue, k + 1);
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	scp->scsi_done(scp); /* callback to mid level */
}

/* When high resolution timer goes off this function is called. */
static enum hrtimer_restart
sdebug_q_cmd_hrt_complete(struct hrtimer *timer)
{
	int qa_indx;
	int retiring = 0;
	unsigned long iflags;
	struct sdebug_hrtimer *sd_hrtp = (struct sdebug_hrtimer *)timer;
	struct sdebug_queued_cmd *sqcp;
	struct scsi_cmnd *scp;
	struct sdebug_dev_info *devip;

	atomic_inc(&sdebug_completions);
	qa_indx = sd_hrtp->qa_indx;
	if ((qa_indx < 0) || (qa_indx >= SCSI_DEBUG_CANQUEUE)) {
		pr_err("%s: wild qa_indx=%d\n", __func__, qa_indx);
		goto the_end;
	}
	spin_lock_irqsave(&queued_arr_lock, iflags);
	sqcp = &queued_arr[qa_indx];
	scp = sqcp->a_cmnd;
	if (NULL == scp) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		pr_err("%s: scp is NULL\n", __func__);
		goto the_end;
	}
	devip = (struct sdebug_dev_info *)scp->device->hostdata;
	if (devip)
		atomic_dec(&devip->num_in_q);
	else
		pr_err("%s: devip=NULL\n", __func__);
	if (atomic_read(&retired_max_queue) > 0)
		retiring = 1;

	sqcp->a_cmnd = NULL;
	if (!test_and_clear_bit(qa_indx, queued_in_use_bm)) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		pr_err("%s: Unexpected completion\n", __func__);
		goto the_end;
	}

	if (unlikely(retiring)) {	/* user has reduced max_queue */
		int k, retval;

		retval = atomic_read(&retired_max_queue);
		if (qa_indx >= retval) {
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
			pr_err("%s: index %d too large\n", __func__, retval);
			goto the_end;
		}
		k = find_last_bit(queued_in_use_bm, retval);
		if ((k < scsi_debug_max_queue) || (k == retval))
			atomic_set(&retired_max_queue, 0);
		else
			atomic_set(&retired_max_queue, k + 1);
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	scp->scsi_done(scp); /* callback to mid level */
the_end:
	return HRTIMER_NORESTART;
}

static struct sdebug_dev_info *
sdebug_device_create(struct sdebug_host_info *sdbg_host, gfp_t flags)
{
	struct sdebug_dev_info *devip;

	devip = kzalloc(sizeof(*devip), flags);
	if (devip) {
		devip->sdbg_host = sdbg_host;
		list_add_tail(&devip->dev_list, &sdbg_host->dev_info_list);
	}
	return devip;
}

static struct sdebug_dev_info * devInfoReg(struct scsi_device * sdev)
{
	struct sdebug_host_info * sdbg_host;
	struct sdebug_dev_info * open_devip = NULL;
	struct sdebug_dev_info * devip =
			(struct sdebug_dev_info *)sdev->hostdata;

	if (devip)
		return devip;
	sdbg_host = *(struct sdebug_host_info **)shost_priv(sdev->host);
	if (!sdbg_host) {
		pr_err("%s: Host info NULL\n", __func__);
		return NULL;
        }
	list_for_each_entry(devip, &sdbg_host->dev_info_list, dev_list) {
		if ((devip->used) && (devip->channel == sdev->channel) &&
                    (devip->target == sdev->id) &&
                    (devip->lun == sdev->lun))
                        return devip;
		else {
			if ((!devip->used) && (!open_devip))
				open_devip = devip;
		}
	}
	if (!open_devip) { /* try and make a new one */
		open_devip = sdebug_device_create(sdbg_host, GFP_ATOMIC);
		if (!open_devip) {
			printk(KERN_ERR "%s: out of memory at line %d\n",
				__func__, __LINE__);
			return NULL;
		}
	}

	open_devip->channel = sdev->channel;
	open_devip->target = sdev->id;
	open_devip->lun = sdev->lun;
	open_devip->sdbg_host = sdbg_host;
	atomic_set(&open_devip->num_in_q, 0);
	set_bit(SDEBUG_UA_POR, open_devip->uas_bm);
	open_devip->used = 1;
	if (sdev->lun == SAM2_WLUN_REPORT_LUNS)
		open_devip->wlun = SAM2_WLUN_REPORT_LUNS & 0xff;

	return open_devip;
}

static int scsi_debug_slave_alloc(struct scsi_device *sdp)
{
	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: slave_alloc <%u %u %u %llu>\n",
		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
	queue_flag_set_unlocked(QUEUE_FLAG_BIDI, sdp->request_queue);
	return 0;
}

static int scsi_debug_slave_configure(struct scsi_device *sdp)
{
	struct sdebug_dev_info *devip;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: slave_configure <%u %u %u %llu>\n",
		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
	if (sdp->host->max_cmd_len != SCSI_DEBUG_MAX_CMD_LEN)
		sdp->host->max_cmd_len = SCSI_DEBUG_MAX_CMD_LEN;
	devip = devInfoReg(sdp);
	if (NULL == devip)
		return 1;	/* no resources, will be marked offline */
	sdp->hostdata = devip;
	sdp->tagged_supported = 1;
	if (sdp->host->cmd_per_lun)
		scsi_adjust_queue_depth(sdp, DEF_TAGGED_QUEUING,
					DEF_CMD_PER_LUN);
	blk_queue_max_segment_size(sdp->request_queue, -1U);
	if (scsi_debug_no_uld)
		sdp->no_uld_attach = 1;
	return 0;
}

static void scsi_debug_slave_destroy(struct scsi_device *sdp)
{
	struct sdebug_dev_info *devip =
		(struct sdebug_dev_info *)sdp->hostdata;

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
		printk(KERN_INFO "scsi_debug: slave_destroy <%u %u %u %llu>\n",
		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
	if (devip) {
		/* make this slot available for re-use */
		devip->used = 0;
		sdp->hostdata = NULL;
	}
}

/* Returns 1 if cmnd found (deletes its timer or tasklet), else returns 0 */
static int stop_queued_cmnd(struct scsi_cmnd *cmnd)
{
	unsigned long iflags;
	int k, qmax, r_qmax;
	struct sdebug_queued_cmd *sqcp;
	struct sdebug_dev_info *devip;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	qmax = scsi_debug_max_queue;
	r_qmax = atomic_read(&retired_max_queue);
	if (r_qmax > qmax)
		qmax = r_qmax;
	for (k = 0; k < qmax; ++k) {
		if (test_bit(k, queued_in_use_bm)) {
			sqcp = &queued_arr[k];
			if (cmnd == sqcp->a_cmnd) {
				devip = (struct sdebug_dev_info *)
					cmnd->device->hostdata;
				if (devip)
					atomic_dec(&devip->num_in_q);
				sqcp->a_cmnd = NULL;
				spin_unlock_irqrestore(&queued_arr_lock,
						       iflags);
				if (scsi_debug_ndelay > 0) {
					if (sqcp->sd_hrtp)
						hrtimer_cancel(
							&sqcp->sd_hrtp->hrt);
				} else if (scsi_debug_delay > 0) {
					if (sqcp->cmnd_timerp)
						del_timer_sync(
							sqcp->cmnd_timerp);
				} else if (scsi_debug_delay < 0) {
					if (sqcp->tletp)
						tasklet_kill(sqcp->tletp);
				}
				clear_bit(k, queued_in_use_bm);
				return 1;
			}
		}
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	return 0;
}

/* Deletes (stops) timers or tasklets of all queued commands */
static void stop_all_queued(void)
{
	unsigned long iflags;
	int k;
	struct sdebug_queued_cmd *sqcp;
	struct sdebug_dev_info *devip;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
		if (test_bit(k, queued_in_use_bm)) {
			sqcp = &queued_arr[k];
			if (sqcp->a_cmnd) {
				devip = (struct sdebug_dev_info *)
					sqcp->a_cmnd->device->hostdata;
				if (devip)
					atomic_dec(&devip->num_in_q);
				sqcp->a_cmnd = NULL;
				spin_unlock_irqrestore(&queued_arr_lock,
						       iflags);
				if (scsi_debug_ndelay > 0) {
					if (sqcp->sd_hrtp)
						hrtimer_cancel(
							&sqcp->sd_hrtp->hrt);
				} else if (scsi_debug_delay > 0) {
					if (sqcp->cmnd_timerp)
						del_timer_sync(
							sqcp->cmnd_timerp);
				} else if (scsi_debug_delay < 0) {
					if (sqcp->tletp)
						tasklet_kill(sqcp->tletp);
				}
				clear_bit(k, queued_in_use_bm);
				spin_lock_irqsave(&queued_arr_lock, iflags);
			}
		}
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

/* Free queued command memory on heap */
static void free_all_queued(void)
{
	unsigned long iflags;
	int k;
	struct sdebug_queued_cmd *sqcp;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
		sqcp = &queued_arr[k];
		kfree(sqcp->cmnd_timerp);
		sqcp->cmnd_timerp = NULL;
		kfree(sqcp->tletp);
		sqcp->tletp = NULL;
		kfree(sqcp->sd_hrtp);
		sqcp->sd_hrtp = NULL;
	}
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

static int scsi_debug_abort(struct scsi_cmnd *SCpnt)
{
	++num_aborts;
	if (SCpnt) {
		if (SCpnt->device &&
		    (SCSI_DEBUG_OPT_ALL_NOISE & scsi_debug_opts))
			sdev_printk(KERN_INFO, SCpnt->device, "%s\n",
				    __func__);
		stop_queued_cmnd(SCpnt);
	}
	return SUCCESS;
}

static int scsi_debug_device_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_dev_info * devip;

	++num_dev_resets;
	if (SCpnt && SCpnt->device) {
		struct scsi_device *sdp = SCpnt->device;

		if (SCSI_DEBUG_OPT_ALL_NOISE & scsi_debug_opts)
			sdev_printk(KERN_INFO, sdp, "%s\n", __func__);
		devip = devInfoReg(sdp);
		if (devip)
			set_bit(SDEBUG_UA_POR, devip->uas_bm);
	}
	return SUCCESS;
}

static int scsi_debug_target_reset(struct scsi_cmnd *SCpnt)
{
	struct sdebug_host_info *sdbg_host;
	struct sdebug_dev_info *devip;
	struct scsi_device *sdp;
	struct Scsi_Host *hp;
	int k = 0;

	++num_target_resets;
	if (!SCpnt)
		goto lie;
	sdp = SCpnt->device;
	if (!sdp)
		goto lie;
	if (SCSI_DEBUG_OPT_ALL_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp, "%s\n", __func__);
	hp = sdp->host;
	if (!hp)
		goto lie;
	sdbg_host = *(struct sdebug_host_info **)shost_priv(hp);
	if (sdbg_host) {
		list_for_each_entry(devip,
				    &sdbg_host->dev_info_list,
				    dev_list)
			if (devip->target == sdp->id) {
				set_bit(SDEBUG_UA_BUS_RESET, devip->uas_bm);
				++k;
			}
	}
	if (SCSI_DEBUG_OPT_RESET_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp,
			    "%s: %d device(s) found in target\n", __func__, k);
lie:
	return SUCCESS;
}

static int scsi_debug_bus_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_host_info *sdbg_host;
	struct sdebug_dev_info *devip;
        struct scsi_device * sdp;
        struct Scsi_Host * hp;
	int k = 0;

	++num_bus_resets;
	if (!(SCpnt && SCpnt->device))
		goto lie;
	sdp = SCpnt->device;
	if (SCSI_DEBUG_OPT_ALL_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp, "%s\n", __func__);
	hp = sdp->host;
	if (hp) {
		sdbg_host = *(struct sdebug_host_info **)shost_priv(hp);
		if (sdbg_host) {
			list_for_each_entry(devip,
                                            &sdbg_host->dev_info_list,
					    dev_list) {
				set_bit(SDEBUG_UA_BUS_RESET, devip->uas_bm);
				++k;
			}
		}
	}
	if (SCSI_DEBUG_OPT_RESET_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, sdp,
			    "%s: %d device(s) found in host\n", __func__, k);
lie:
	return SUCCESS;
}

static int scsi_debug_host_reset(struct scsi_cmnd * SCpnt)
{
	struct sdebug_host_info * sdbg_host;
	struct sdebug_dev_info *devip;
	int k = 0;

	++num_host_resets;
	if ((SCpnt->device) && (SCSI_DEBUG_OPT_ALL_NOISE & scsi_debug_opts))
		sdev_printk(KERN_INFO, SCpnt->device, "%s\n", __func__);
        spin_lock(&sdebug_host_list_lock);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
		list_for_each_entry(devip, &sdbg_host->dev_info_list,
				    dev_list) {
			set_bit(SDEBUG_UA_BUS_RESET, devip->uas_bm);
			++k;
		}
        }
        spin_unlock(&sdebug_host_list_lock);
	stop_all_queued();
	if (SCSI_DEBUG_OPT_RESET_NOISE & scsi_debug_opts)
		sdev_printk(KERN_INFO, SCpnt->device,
			    "%s: %d device(s) found\n", __func__, k);
	return SUCCESS;
}

static void __init sdebug_build_parts(unsigned char *ramp,
				      unsigned long store_size)
{
	struct partition * pp;
	int starts[SDEBUG_MAX_PARTS + 2];
	int sectors_per_part, num_sectors, k;
	int heads_by_sects, start_sec, end_sec;

	/* assume partition table already zeroed */
	if ((scsi_debug_num_parts < 1) || (store_size < 1048576))
		return;
	if (scsi_debug_num_parts > SDEBUG_MAX_PARTS) {
		scsi_debug_num_parts = SDEBUG_MAX_PARTS;
		pr_warn("%s: reducing partitions to %d\n", __func__,
			SDEBUG_MAX_PARTS);
	}
	num_sectors = (int)sdebug_store_sectors;
	sectors_per_part = (num_sectors - sdebug_sectors_per)
			   / scsi_debug_num_parts;
	heads_by_sects = sdebug_heads * sdebug_sectors_per;
        starts[0] = sdebug_sectors_per;
	for (k = 1; k < scsi_debug_num_parts; ++k)
		starts[k] = ((k * sectors_per_part) / heads_by_sects)
			    * heads_by_sects;
	starts[scsi_debug_num_parts] = num_sectors;
	starts[scsi_debug_num_parts + 1] = 0;

	ramp[510] = 0x55;	/* magic partition markings */
	ramp[511] = 0xAA;
	pp = (struct partition *)(ramp + 0x1be);
	for (k = 0; starts[k + 1]; ++k, ++pp) {
		start_sec = starts[k];
		end_sec = starts[k + 1] - 1;
		pp->boot_ind = 0;

		pp->cyl = start_sec / heads_by_sects;
		pp->head = (start_sec - (pp->cyl * heads_by_sects))
			   / sdebug_sectors_per;
		pp->sector = (start_sec % sdebug_sectors_per) + 1;

		pp->end_cyl = end_sec / heads_by_sects;
		pp->end_head = (end_sec - (pp->end_cyl * heads_by_sects))
			       / sdebug_sectors_per;
		pp->end_sector = (end_sec % sdebug_sectors_per) + 1;

		pp->start_sect = cpu_to_le32(start_sec);
		pp->nr_sects = cpu_to_le32(end_sec - start_sec + 1);
		pp->sys_ind = 0x83;	/* plain Linux partition */
	}
}

static int
schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip,
	      int scsi_result, int delta_jiff)
{
	unsigned long iflags;
	int k, num_in_q, qdepth, inject;
	struct sdebug_queued_cmd *sqcp = NULL;
	struct scsi_device *sdp = cmnd->device;

	if (NULL == cmnd || NULL == devip) {
		pr_warn("%s: called with NULL cmnd or devip pointer\n",
			__func__);
		/* no particularly good error to report back */
		return SCSI_MLQUEUE_HOST_BUSY;
	}
	if ((scsi_result) && (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts))
		sdev_printk(KERN_INFO, sdp, "%s: non-zero result=0x%x\n",
			    __func__, scsi_result);
	if (delta_jiff == 0)
		goto respond_in_thread;

	/* schedule the response at a later time if resources permit */
	spin_lock_irqsave(&queued_arr_lock, iflags);
	num_in_q = atomic_read(&devip->num_in_q);
	qdepth = cmnd->device->queue_depth;
	inject = 0;
	if ((qdepth > 0) && (num_in_q >= qdepth)) {
		if (scsi_result) {
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
			goto respond_in_thread;
		} else
			scsi_result = device_qfull_result;
	} else if ((scsi_debug_every_nth != 0) &&
		   (SCSI_DEBUG_OPT_RARE_TSF & scsi_debug_opts) &&
		   (scsi_result == 0)) {
		if ((num_in_q == (qdepth - 1)) &&
		    (atomic_inc_return(&sdebug_a_tsf) >=
		     abs(scsi_debug_every_nth))) {
			atomic_set(&sdebug_a_tsf, 0);
			inject = 1;
			scsi_result = device_qfull_result;
		}
	}

	k = find_first_zero_bit(queued_in_use_bm, scsi_debug_max_queue);
	if (k >= scsi_debug_max_queue) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		if (scsi_result)
			goto respond_in_thread;
		else if (SCSI_DEBUG_OPT_ALL_TSF & scsi_debug_opts)
			scsi_result = device_qfull_result;
		if (SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts)
			sdev_printk(KERN_INFO, sdp,
				    "%s: max_queue=%d exceeded, %s\n",
				    __func__, scsi_debug_max_queue,
				    (scsi_result ?  "status: TASK SET FULL" :
						    "report: host busy"));
		if (scsi_result)
			goto respond_in_thread;
		else
			return SCSI_MLQUEUE_HOST_BUSY;
	}
	__set_bit(k, queued_in_use_bm);
	atomic_inc(&devip->num_in_q);
	sqcp = &queued_arr[k];
	sqcp->a_cmnd = cmnd;
	cmnd->result = scsi_result;
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	if (delta_jiff > 0) {
		if (NULL == sqcp->cmnd_timerp) {
			sqcp->cmnd_timerp = kmalloc(sizeof(struct timer_list),
						    GFP_ATOMIC);
			if (NULL == sqcp->cmnd_timerp)
				return SCSI_MLQUEUE_HOST_BUSY;
			init_timer(sqcp->cmnd_timerp);
		}
		sqcp->cmnd_timerp->function = sdebug_q_cmd_complete;
		sqcp->cmnd_timerp->data = k;
		sqcp->cmnd_timerp->expires = get_jiffies_64() + delta_jiff;
		add_timer(sqcp->cmnd_timerp);
	} else if (scsi_debug_ndelay > 0) {
		ktime_t kt = ktime_set(0, scsi_debug_ndelay);
		struct sdebug_hrtimer *sd_hp = sqcp->sd_hrtp;

		if (NULL == sd_hp) {
			sd_hp = kmalloc(sizeof(*sd_hp), GFP_ATOMIC);
			if (NULL == sd_hp)
				return SCSI_MLQUEUE_HOST_BUSY;
			sqcp->sd_hrtp = sd_hp;
			hrtimer_init(&sd_hp->hrt, CLOCK_MONOTONIC,
				     HRTIMER_MODE_REL);
			sd_hp->hrt.function = sdebug_q_cmd_hrt_complete;
			sd_hp->qa_indx = k;
		}
		hrtimer_start(&sd_hp->hrt, kt, HRTIMER_MODE_REL);
	} else {	/* delay < 0 */
		if (NULL == sqcp->tletp) {
			sqcp->tletp = kmalloc(sizeof(*sqcp->tletp),
					      GFP_ATOMIC);
			if (NULL == sqcp->tletp)
				return SCSI_MLQUEUE_HOST_BUSY;
			tasklet_init(sqcp->tletp,
				     sdebug_q_cmd_complete, k);
		}
		if (-1 == delta_jiff)
			tasklet_hi_schedule(sqcp->tletp);
		else
			tasklet_schedule(sqcp->tletp);
	}
	if ((SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts) &&
	    (scsi_result == device_qfull_result))
		sdev_printk(KERN_INFO, sdp,
			    "%s: num_in_q=%d +1, %s%s\n", __func__,
			    num_in_q, (inject ? "<inject> " : ""),
			    "status: TASK SET FULL");
	return 0;

respond_in_thread:	/* call back to mid-layer using invocation thread */
	cmnd->result = scsi_result;
	cmnd->scsi_done(cmnd);
	return 0;
}

/* Note: The following macros create attribute files in the
   /sys/module/scsi_debug/parameters directory. Unfortunately this
   driver is unaware of a change and cannot trigger auxiliary actions
   as it can when the corresponding attribute in the
   /sys/bus/pseudo/drivers/scsi_debug directory is changed.
 */
module_param_named(add_host, scsi_debug_add_host, int, S_IRUGO | S_IWUSR);
module_param_named(ato, scsi_debug_ato, int, S_IRUGO);
module_param_named(clustering, scsi_debug_clustering, bool, S_IRUGO | S_IWUSR);
module_param_named(delay, scsi_debug_delay, int, S_IRUGO | S_IWUSR);
module_param_named(dev_size_mb, scsi_debug_dev_size_mb, int, S_IRUGO);
module_param_named(dif, scsi_debug_dif, int, S_IRUGO);
module_param_named(dix, scsi_debug_dix, int, S_IRUGO);
module_param_named(dsense, scsi_debug_dsense, int, S_IRUGO | S_IWUSR);
module_param_named(every_nth, scsi_debug_every_nth, int, S_IRUGO | S_IWUSR);
module_param_named(fake_rw, scsi_debug_fake_rw, int, S_IRUGO | S_IWUSR);
module_param_named(guard, scsi_debug_guard, uint, S_IRUGO);
module_param_named(host_lock, scsi_debug_host_lock, bool, S_IRUGO | S_IWUSR);
module_param_named(lbpu, scsi_debug_lbpu, int, S_IRUGO);
module_param_named(lbpws, scsi_debug_lbpws, int, S_IRUGO);
module_param_named(lbpws10, scsi_debug_lbpws10, int, S_IRUGO);
module_param_named(lbprz, scsi_debug_lbprz, int, S_IRUGO);
module_param_named(lowest_aligned, scsi_debug_lowest_aligned, int, S_IRUGO);
module_param_named(max_luns, scsi_debug_max_luns, int, S_IRUGO | S_IWUSR);
module_param_named(max_queue, scsi_debug_max_queue, int, S_IRUGO | S_IWUSR);
module_param_named(ndelay, scsi_debug_ndelay, int, S_IRUGO | S_IWUSR);
module_param_named(no_lun_0, scsi_debug_no_lun_0, int, S_IRUGO | S_IWUSR);
module_param_named(no_uld, scsi_debug_no_uld, int, S_IRUGO);
module_param_named(num_parts, scsi_debug_num_parts, int, S_IRUGO);
module_param_named(num_tgts, scsi_debug_num_tgts, int, S_IRUGO | S_IWUSR);
module_param_named(opt_blks, scsi_debug_opt_blks, int, S_IRUGO);
module_param_named(opts, scsi_debug_opts, int, S_IRUGO | S_IWUSR);
module_param_named(physblk_exp, scsi_debug_physblk_exp, int, S_IRUGO);
module_param_named(ptype, scsi_debug_ptype, int, S_IRUGO | S_IWUSR);
module_param_named(removable, scsi_debug_removable, bool, S_IRUGO | S_IWUSR);
module_param_named(scsi_level, scsi_debug_scsi_level, int, S_IRUGO);
module_param_named(sector_size, scsi_debug_sector_size, int, S_IRUGO);
module_param_named(unmap_alignment, scsi_debug_unmap_alignment, int, S_IRUGO);
module_param_named(unmap_granularity, scsi_debug_unmap_granularity, int, S_IRUGO);
module_param_named(unmap_max_blocks, scsi_debug_unmap_max_blocks, int, S_IRUGO);
module_param_named(unmap_max_desc, scsi_debug_unmap_max_desc, int, S_IRUGO);
module_param_named(virtual_gb, scsi_debug_virtual_gb, int, S_IRUGO | S_IWUSR);
module_param_named(vpd_use_hostno, scsi_debug_vpd_use_hostno, int,
		   S_IRUGO | S_IWUSR);
module_param_named(write_same_length, scsi_debug_write_same_length, int,
		   S_IRUGO | S_IWUSR);

MODULE_AUTHOR("Eric Youngdale + Douglas Gilbert");
MODULE_DESCRIPTION("SCSI debug adapter driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(SCSI_DEBUG_VERSION);

MODULE_PARM_DESC(add_host, "0..127 hosts allowed(def=1)");
MODULE_PARM_DESC(ato, "application tag ownership: 0=disk 1=host (def=1)");
MODULE_PARM_DESC(clustering, "when set enables larger transfers (def=0)");
MODULE_PARM_DESC(delay, "response delay (def=1 jiffy); 0:imm, -1,-2:tiny");
MODULE_PARM_DESC(dev_size_mb, "size in MB of ram shared by devs(def=8)");
MODULE_PARM_DESC(dif, "data integrity field type: 0-3 (def=0)");
MODULE_PARM_DESC(dix, "data integrity extensions mask (def=0)");
MODULE_PARM_DESC(dsense, "use descriptor sense format(def=0 -> fixed)");
MODULE_PARM_DESC(every_nth, "timeout every nth command(def=0)");
MODULE_PARM_DESC(fake_rw, "fake reads/writes instead of copying (def=0)");
MODULE_PARM_DESC(guard, "protection checksum: 0=crc, 1=ip (def=0)");
MODULE_PARM_DESC(host_lock, "use host_lock around all commands (def=0)");
MODULE_PARM_DESC(lbpu, "enable LBP, support UNMAP command (def=0)");
MODULE_PARM_DESC(lbpws, "enable LBP, support WRITE SAME(16) with UNMAP bit (def=0)");
MODULE_PARM_DESC(lbpws10, "enable LBP, support WRITE SAME(10) with UNMAP bit (def=0)");
MODULE_PARM_DESC(lbprz, "unmapped blocks return 0 on read (def=1)");
MODULE_PARM_DESC(lowest_aligned, "lowest aligned lba (def=0)");
MODULE_PARM_DESC(max_luns, "number of LUNs per target to simulate(def=1)");
MODULE_PARM_DESC(max_queue, "max number of queued commands (1 to max(def))");
MODULE_PARM_DESC(ndelay, "response delay in nanoseconds (def=0 -> ignore)");
MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)");
MODULE_PARM_DESC(no_uld, "stop ULD (e.g. sd driver) attaching (def=0))");
MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");
MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)");
MODULE_PARM_DESC(opt_blks, "optimal transfer length in block (def=64)");
MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)");
MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)");
MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");
MODULE_PARM_DESC(removable, "claim to have removable media (def=0)");
MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=6[SPC-4])");
MODULE_PARM_DESC(sector_size, "logical block size in bytes (def=512)");
MODULE_PARM_DESC(unmap_alignment, "lowest aligned thin provisioning lba (def=0)");
MODULE_PARM_DESC(unmap_granularity, "thin provisioning granularity in blocks (def=1)");
MODULE_PARM_DESC(unmap_max_blocks, "max # of blocks can be unmapped in one cmd (def=0xffffffff)");
MODULE_PARM_DESC(unmap_max_desc, "max # of ranges that can be unmapped in one cmd (def=256)");
MODULE_PARM_DESC(virtual_gb, "virtual gigabyte size (def=0 -> use dev_size_mb)");
MODULE_PARM_DESC(vpd_use_hostno, "0 -> dev ids ignore hostno (def=1 -> unique dev ids)");
MODULE_PARM_DESC(write_same_length, "Maximum blocks per WRITE SAME cmd (def=0xffff)");

static char sdebug_info[256];

static const char * scsi_debug_info(struct Scsi_Host * shp)
{
	sprintf(sdebug_info, "scsi_debug, version %s [%s], "
		"dev_size_mb=%d, opts=0x%x", SCSI_DEBUG_VERSION,
		scsi_debug_version_date, scsi_debug_dev_size_mb,
		scsi_debug_opts);
	return sdebug_info;
}

/* 'echo <val> > /proc/scsi/scsi_debug/<host_id>' writes to opts */
static int scsi_debug_write_info(struct Scsi_Host *host, char *buffer, int length)
{
	char arr[16];
	int opts;
	int minLen = length > 15 ? 15 : length;

	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
		return -EACCES;
	memcpy(arr, buffer, minLen);
	arr[minLen] = '\0';
	if (1 != sscanf(arr, "%d", &opts))
		return -EINVAL;
	scsi_debug_opts = opts;
	if (scsi_debug_every_nth != 0)
		atomic_set(&sdebug_cmnd_count, 0);
	return length;
}

/* Output seen with 'cat /proc/scsi/scsi_debug/<host_id>'. It will be the
 * same for each scsi_debug host (if more than one). Some of the counters
 * output are not atomics so might be inaccurate in a busy system. */
static int scsi_debug_show_info(struct seq_file *m, struct Scsi_Host *host)
{
	int f, l;
	char b[32];

	if (scsi_debug_every_nth > 0)
		snprintf(b, sizeof(b), " (curr:%d)",
			 ((SCSI_DEBUG_OPT_RARE_TSF & scsi_debug_opts) ?
				atomic_read(&sdebug_a_tsf) :
				atomic_read(&sdebug_cmnd_count)));
	else
		b[0] = '\0';

	seq_printf(m, "scsi_debug adapter driver, version %s [%s]\n"
		"num_tgts=%d, shared (ram) size=%d MB, opts=0x%x, "
		"every_nth=%d%s\n"
		"delay=%d, ndelay=%d, max_luns=%d, q_completions=%d\n"
		"sector_size=%d bytes, cylinders=%d, heads=%d, sectors=%d\n"
		"command aborts=%d; RESETs: device=%d, target=%d, bus=%d, "
		"host=%d\ndix_reads=%d dix_writes=%d dif_errors=%d "
		"usec_in_jiffy=%lu\n",
		SCSI_DEBUG_VERSION, scsi_debug_version_date,
		scsi_debug_num_tgts, scsi_debug_dev_size_mb, scsi_debug_opts,
		scsi_debug_every_nth, b, scsi_debug_delay, scsi_debug_ndelay,
		scsi_debug_max_luns, atomic_read(&sdebug_completions),
		scsi_debug_sector_size, sdebug_cylinders_per, sdebug_heads,
		sdebug_sectors_per, num_aborts, num_dev_resets,
		num_target_resets, num_bus_resets, num_host_resets,
		dix_reads, dix_writes, dif_errors, TICK_NSEC / 1000);

	f = find_first_bit(queued_in_use_bm, scsi_debug_max_queue);
	if (f != scsi_debug_max_queue) {
		l = find_last_bit(queued_in_use_bm, scsi_debug_max_queue);
		seq_printf(m, "   %s BUSY: first,last bits set: %d,%d\n",
			   "queued_in_use_bm", f, l);
	}
	return 0;
}

static ssize_t delay_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_delay);
}
/* Returns -EBUSY if delay is being changed and commands are queued */
static ssize_t delay_store(struct device_driver *ddp, const char *buf,
			   size_t count)
{
	int delay, res;

	if ((count > 0) && (1 == sscanf(buf, "%d", &delay))) {
		res = count;
		if (scsi_debug_delay != delay) {
			unsigned long iflags;
			int k;

			spin_lock_irqsave(&queued_arr_lock, iflags);
			k = find_first_bit(queued_in_use_bm,
					   scsi_debug_max_queue);
			if (k != scsi_debug_max_queue)
				res = -EBUSY;	/* have queued commands */
			else {
				scsi_debug_delay = delay;
				scsi_debug_ndelay = 0;
			}
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
		}
		return res;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(delay);

static ssize_t ndelay_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_ndelay);
}
/* Returns -EBUSY if ndelay is being changed and commands are queued */
/* If > 0 and accepted then scsi_debug_delay is set to DELAY_OVERRIDDEN */
static ssize_t ndelay_store(struct device_driver *ddp, const char *buf,
			   size_t count)
{
	unsigned long iflags;
	int ndelay, res, k;

	if ((count > 0) && (1 == sscanf(buf, "%d", &ndelay)) &&
	    (ndelay >= 0) && (ndelay < 1000000000)) {
		res = count;
		if (scsi_debug_ndelay != ndelay) {
			spin_lock_irqsave(&queued_arr_lock, iflags);
			k = find_first_bit(queued_in_use_bm,
					   scsi_debug_max_queue);
			if (k != scsi_debug_max_queue)
				res = -EBUSY;	/* have queued commands */
			else {
				scsi_debug_ndelay = ndelay;
				scsi_debug_delay = ndelay ? DELAY_OVERRIDDEN
							  : DEF_DELAY;
			}
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
		}
		return res;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(ndelay);

static ssize_t opts_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "0x%x\n", scsi_debug_opts);
}

static ssize_t opts_store(struct device_driver *ddp, const char *buf,
			  size_t count)
{
        int opts;
	char work[20];

        if (1 == sscanf(buf, "%10s", work)) {
		if (0 == strncasecmp(work,"0x", 2)) {
			if (1 == sscanf(&work[2], "%x", &opts))
				goto opts_done;
		} else {
			if (1 == sscanf(work, "%d", &opts))
				goto opts_done;
		}
	}
	return -EINVAL;
opts_done:
	scsi_debug_opts = opts;
	atomic_set(&sdebug_cmnd_count, 0);
	atomic_set(&sdebug_a_tsf, 0);
	return count;
}
static DRIVER_ATTR_RW(opts);

static ssize_t ptype_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_ptype);
}
static ssize_t ptype_store(struct device_driver *ddp, const char *buf,
			   size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_ptype = n;
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(ptype);

static ssize_t dsense_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dsense);
}
static ssize_t dsense_store(struct device_driver *ddp, const char *buf,
			    size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_dsense = n;
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(dsense);

static ssize_t fake_rw_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_fake_rw);
}
static ssize_t fake_rw_store(struct device_driver *ddp, const char *buf,
			     size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		n = (n > 0);
		scsi_debug_fake_rw = (scsi_debug_fake_rw > 0);
		if (scsi_debug_fake_rw != n) {
			if ((0 == n) && (NULL == fake_storep)) {
				unsigned long sz =
					(unsigned long)scsi_debug_dev_size_mb *
					1048576;

				fake_storep = vmalloc(sz);
				if (NULL == fake_storep) {
					pr_err("%s: out of memory, 9\n",
					       __func__);
					return -ENOMEM;
				}
				memset(fake_storep, 0, sz);
			}
			scsi_debug_fake_rw = n;
		}
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(fake_rw);

static ssize_t no_lun_0_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_no_lun_0);
}
static ssize_t no_lun_0_store(struct device_driver *ddp, const char *buf,
			      size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_no_lun_0 = n;
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(no_lun_0);

static ssize_t num_tgts_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_num_tgts);
}
static ssize_t num_tgts_store(struct device_driver *ddp, const char *buf,
			      size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_num_tgts = n;
		sdebug_max_tgts_luns();
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(num_tgts);

static ssize_t dev_size_mb_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dev_size_mb);
}
static DRIVER_ATTR_RO(dev_size_mb);

static ssize_t num_parts_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_num_parts);
}
static DRIVER_ATTR_RO(num_parts);

static ssize_t every_nth_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_every_nth);
}
static ssize_t every_nth_store(struct device_driver *ddp, const char *buf,
			       size_t count)
{
        int nth;

	if ((count > 0) && (1 == sscanf(buf, "%d", &nth))) {
		scsi_debug_every_nth = nth;
		atomic_set(&sdebug_cmnd_count, 0);
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(every_nth);

static ssize_t max_luns_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_max_luns);
}
static ssize_t max_luns_store(struct device_driver *ddp, const char *buf,
			      size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_max_luns = n;
		sdebug_max_tgts_luns();
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(max_luns);

static ssize_t max_queue_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_max_queue);
}
/* N.B. max_queue can be changed while there are queued commands. In flight
 * commands beyond the new max_queue will be completed. */
static ssize_t max_queue_store(struct device_driver *ddp, const char *buf,
			       size_t count)
{
	unsigned long iflags;
	int n, k;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n > 0) &&
	    (n <= SCSI_DEBUG_CANQUEUE)) {
		spin_lock_irqsave(&queued_arr_lock, iflags);
		k = find_last_bit(queued_in_use_bm, SCSI_DEBUG_CANQUEUE);
		scsi_debug_max_queue = n;
		if (SCSI_DEBUG_CANQUEUE == k)
			atomic_set(&retired_max_queue, 0);
		else if (k >= n)
			atomic_set(&retired_max_queue, k + 1);
		else
			atomic_set(&retired_max_queue, 0);
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(max_queue);

static ssize_t no_uld_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_no_uld);
}
static DRIVER_ATTR_RO(no_uld);

static ssize_t scsi_level_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_scsi_level);
}
static DRIVER_ATTR_RO(scsi_level);

static ssize_t virtual_gb_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_virtual_gb);
}
static ssize_t virtual_gb_store(struct device_driver *ddp, const char *buf,
				size_t count)
{
        int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_virtual_gb = n;

		sdebug_capacity = get_sdebug_capacity();

		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(virtual_gb);

static ssize_t add_host_show(struct device_driver *ddp, char *buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_add_host);
}

static ssize_t add_host_store(struct device_driver *ddp, const char *buf,
			      size_t count)
{
	int delta_hosts;

	if (sscanf(buf, "%d", &delta_hosts) != 1)
		return -EINVAL;
	if (delta_hosts > 0) {
		do {
			sdebug_add_adapter();
		} while (--delta_hosts);
	} else if (delta_hosts < 0) {
		do {
			sdebug_remove_adapter();
		} while (++delta_hosts);
	}
	return count;
}
static DRIVER_ATTR_RW(add_host);

static ssize_t vpd_use_hostno_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_vpd_use_hostno);
}
static ssize_t vpd_use_hostno_store(struct device_driver *ddp, const char *buf,
				    size_t count)
{
	int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_vpd_use_hostno = n;
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(vpd_use_hostno);

static ssize_t sector_size_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%u\n", scsi_debug_sector_size);
}
static DRIVER_ATTR_RO(sector_size);

static ssize_t dix_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dix);
}
static DRIVER_ATTR_RO(dix);

static ssize_t dif_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_dif);
}
static DRIVER_ATTR_RO(dif);

static ssize_t guard_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%u\n", scsi_debug_guard);
}
static DRIVER_ATTR_RO(guard);

static ssize_t ato_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_ato);
}
static DRIVER_ATTR_RO(ato);

static ssize_t map_show(struct device_driver *ddp, char *buf)
{
	ssize_t count;

	if (!scsi_debug_lbp())
		return scnprintf(buf, PAGE_SIZE, "0-%u\n",
				 sdebug_store_sectors);

	count = bitmap_scnlistprintf(buf, PAGE_SIZE, map_storep, map_size);

	buf[count++] = '\n';
	buf[count++] = 0;

	return count;
}
static DRIVER_ATTR_RO(map);

static ssize_t removable_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_removable ? 1 : 0);
}
static ssize_t removable_store(struct device_driver *ddp, const char *buf,
			       size_t count)
{
	int n;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		scsi_debug_removable = (n > 0);
		return count;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(removable);

static ssize_t host_lock_show(struct device_driver *ddp, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%d\n", !!scsi_debug_host_lock);
}
/* Returns -EBUSY if host_lock is being changed and commands are queued */
static ssize_t host_lock_store(struct device_driver *ddp, const char *buf,
			       size_t count)
{
	int n, res;

	if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
		bool new_host_lock = (n > 0);

		res = count;
		if (new_host_lock != scsi_debug_host_lock) {
			unsigned long iflags;
			int k;

			spin_lock_irqsave(&queued_arr_lock, iflags);
			k = find_first_bit(queued_in_use_bm,
					   scsi_debug_max_queue);
			if (k != scsi_debug_max_queue)
				res = -EBUSY;	/* have queued commands */
			else
				scsi_debug_host_lock = new_host_lock;
			spin_unlock_irqrestore(&queued_arr_lock, iflags);
		}
		return res;
	}
	return -EINVAL;
}
static DRIVER_ATTR_RW(host_lock);


/* Note: The following array creates attribute files in the
   /sys/bus/pseudo/drivers/scsi_debug directory. The advantage of these
   files (over those found in the /sys/module/scsi_debug/parameters
   directory) is that auxiliary actions can be triggered when an attribute
   is changed. For example see: sdebug_add_host_store() above.
 */

static struct attribute *sdebug_drv_attrs[] = {
	&driver_attr_delay.attr,
	&driver_attr_opts.attr,
	&driver_attr_ptype.attr,
	&driver_attr_dsense.attr,
	&driver_attr_fake_rw.attr,
	&driver_attr_no_lun_0.attr,
	&driver_attr_num_tgts.attr,
	&driver_attr_dev_size_mb.attr,
	&driver_attr_num_parts.attr,
	&driver_attr_every_nth.attr,
	&driver_attr_max_luns.attr,
	&driver_attr_max_queue.attr,
	&driver_attr_no_uld.attr,
	&driver_attr_scsi_level.attr,
	&driver_attr_virtual_gb.attr,
	&driver_attr_add_host.attr,
	&driver_attr_vpd_use_hostno.attr,
	&driver_attr_sector_size.attr,
	&driver_attr_dix.attr,
	&driver_attr_dif.attr,
	&driver_attr_guard.attr,
	&driver_attr_ato.attr,
	&driver_attr_map.attr,
	&driver_attr_removable.attr,
	&driver_attr_host_lock.attr,
	&driver_attr_ndelay.attr,
	NULL,
};
ATTRIBUTE_GROUPS(sdebug_drv);

static struct device *pseudo_primary;

static int __init scsi_debug_init(void)
{
	unsigned long sz;
	int host_to_add;
	int k;
	int ret;

	atomic_set(&sdebug_cmnd_count, 0);
	atomic_set(&sdebug_completions, 0);
	atomic_set(&retired_max_queue, 0);

	if (scsi_debug_ndelay >= 1000000000) {
		pr_warn("%s: ndelay must be less than 1 second, ignored\n",
			__func__);
		scsi_debug_ndelay = 0;
	} else if (scsi_debug_ndelay > 0)
		scsi_debug_delay = DELAY_OVERRIDDEN;

	switch (scsi_debug_sector_size) {
	case  512:
	case 1024:
	case 2048:
	case 4096:
		break;
	default:
		pr_err("%s: invalid sector_size %d\n", __func__,
		       scsi_debug_sector_size);
		return -EINVAL;
	}

	switch (scsi_debug_dif) {

	case SD_DIF_TYPE0_PROTECTION:
	case SD_DIF_TYPE1_PROTECTION:
	case SD_DIF_TYPE2_PROTECTION:
	case SD_DIF_TYPE3_PROTECTION:
		break;

	default:
		pr_err("%s: dif must be 0, 1, 2 or 3\n", __func__);
		return -EINVAL;
	}

	if (scsi_debug_guard > 1) {
		pr_err("%s: guard must be 0 or 1\n", __func__);
		return -EINVAL;
	}

	if (scsi_debug_ato > 1) {
		pr_err("%s: ato must be 0 or 1\n", __func__);
		return -EINVAL;
	}

	if (scsi_debug_physblk_exp > 15) {
		pr_err("%s: invalid physblk_exp %u\n", __func__,
		       scsi_debug_physblk_exp);
		return -EINVAL;
	}

	if (scsi_debug_lowest_aligned > 0x3fff) {
		pr_err("%s: lowest_aligned too big: %u\n", __func__,
		       scsi_debug_lowest_aligned);
		return -EINVAL;
	}

	if (scsi_debug_dev_size_mb < 1)
		scsi_debug_dev_size_mb = 1;  /* force minimum 1 MB ramdisk */
	sz = (unsigned long)scsi_debug_dev_size_mb * 1048576;
	sdebug_store_sectors = sz / scsi_debug_sector_size;
	sdebug_capacity = get_sdebug_capacity();

	/* play around with geometry, don't waste too much on track 0 */
	sdebug_heads = 8;
	sdebug_sectors_per = 32;
	if (scsi_debug_dev_size_mb >= 16)
		sdebug_heads = 32;
	else if (scsi_debug_dev_size_mb >= 256)
		sdebug_heads = 64;
	sdebug_cylinders_per = (unsigned long)sdebug_capacity /
			       (sdebug_sectors_per * sdebug_heads);
	if (sdebug_cylinders_per >= 1024) {
		/* other LLDs do this; implies >= 1GB ram disk ... */
		sdebug_heads = 255;
		sdebug_sectors_per = 63;
		sdebug_cylinders_per = (unsigned long)sdebug_capacity /
			       (sdebug_sectors_per * sdebug_heads);
	}

	if (0 == scsi_debug_fake_rw) {
		fake_storep = vmalloc(sz);
		if (NULL == fake_storep) {
			pr_err("%s: out of memory, 1\n", __func__);
			return -ENOMEM;
		}
		memset(fake_storep, 0, sz);
		if (scsi_debug_num_parts > 0)
			sdebug_build_parts(fake_storep, sz);
	}

	if (scsi_debug_dix) {
		int dif_size;

		dif_size = sdebug_store_sectors * sizeof(struct sd_dif_tuple);
		dif_storep = vmalloc(dif_size);

		pr_err("%s: dif_storep %u bytes @ %p\n", __func__, dif_size,
			dif_storep);

		if (dif_storep == NULL) {
			pr_err("%s: out of mem. (DIX)\n", __func__);
			ret = -ENOMEM;
			goto free_vm;
		}

		memset(dif_storep, 0xff, dif_size);
	}

	/* Logical Block Provisioning */
	if (scsi_debug_lbp()) {
		scsi_debug_unmap_max_blocks =
			clamp(scsi_debug_unmap_max_blocks, 0U, 0xffffffffU);

		scsi_debug_unmap_max_desc =
			clamp(scsi_debug_unmap_max_desc, 0U, 256U);

		scsi_debug_unmap_granularity =
			clamp(scsi_debug_unmap_granularity, 1U, 0xffffffffU);

		if (scsi_debug_unmap_alignment &&
		    scsi_debug_unmap_granularity <=
		    scsi_debug_unmap_alignment) {
			pr_err("%s: ERR: unmap_granularity <= unmap_alignment\n",
			       __func__);
			return -EINVAL;
		}

		map_size = lba_to_map_index(sdebug_store_sectors - 1) + 1;
		map_storep = vmalloc(BITS_TO_LONGS(map_size) * sizeof(long));

		pr_info("%s: %lu provisioning blocks\n", __func__, map_size);

		if (map_storep == NULL) {
			pr_err("%s: out of mem. (MAP)\n", __func__);
			ret = -ENOMEM;
			goto free_vm;
		}

		bitmap_zero(map_storep, map_size);

		/* Map first 1KB for partition table */
		if (scsi_debug_num_parts)
			map_region(0, 2);
	}

	pseudo_primary = root_device_register("pseudo_0");
	if (IS_ERR(pseudo_primary)) {
		pr_warn("%s: root_device_register() error\n", __func__);
		ret = PTR_ERR(pseudo_primary);
		goto free_vm;
	}
	ret = bus_register(&pseudo_lld_bus);
	if (ret < 0) {
		pr_warn("%s: bus_register error: %d\n", __func__, ret);
		goto dev_unreg;
	}
	ret = driver_register(&sdebug_driverfs_driver);
	if (ret < 0) {
		pr_warn("%s: driver_register error: %d\n", __func__, ret);
		goto bus_unreg;
	}

	host_to_add = scsi_debug_add_host;
        scsi_debug_add_host = 0;

        for (k = 0; k < host_to_add; k++) {
                if (sdebug_add_adapter()) {
			pr_err("%s: sdebug_add_adapter failed k=%d\n",
				__func__, k);
                        break;
                }
        }

	if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) {
		pr_info("%s: built %d host(s)\n", __func__,
			scsi_debug_add_host);
	}
	return 0;

bus_unreg:
	bus_unregister(&pseudo_lld_bus);
dev_unreg:
	root_device_unregister(pseudo_primary);
free_vm:
	if (map_storep)
		vfree(map_storep);
	if (dif_storep)
		vfree(dif_storep);
	vfree(fake_storep);

	return ret;
}

static void __exit scsi_debug_exit(void)
{
	int k = scsi_debug_add_host;

	stop_all_queued();
	free_all_queued();
	for (; k; k--)
		sdebug_remove_adapter();
	driver_unregister(&sdebug_driverfs_driver);
	bus_unregister(&pseudo_lld_bus);
	root_device_unregister(pseudo_primary);

	if (dif_storep)
		vfree(dif_storep);

	vfree(map_storep);
	vfree(fake_storep);
}

device_initcall(scsi_debug_init);
module_exit(scsi_debug_exit);

static void sdebug_release_adapter(struct device * dev)
{
        struct sdebug_host_info *sdbg_host;

	sdbg_host = to_sdebug_host(dev);
        kfree(sdbg_host);
}

static int sdebug_add_adapter(void)
{
	int k, devs_per_host;
        int error = 0;
        struct sdebug_host_info *sdbg_host;
	struct sdebug_dev_info *sdbg_devinfo, *tmp;

        sdbg_host = kzalloc(sizeof(*sdbg_host),GFP_KERNEL);
        if (NULL == sdbg_host) {
                printk(KERN_ERR "%s: out of memory at line %d\n",
                       __func__, __LINE__);
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&sdbg_host->dev_info_list);

	devs_per_host = scsi_debug_num_tgts * scsi_debug_max_luns;
        for (k = 0; k < devs_per_host; k++) {
		sdbg_devinfo = sdebug_device_create(sdbg_host, GFP_KERNEL);
		if (!sdbg_devinfo) {
                        printk(KERN_ERR "%s: out of memory at line %d\n",
                               __func__, __LINE__);
                        error = -ENOMEM;
			goto clean;
                }
        }

        spin_lock(&sdebug_host_list_lock);
        list_add_tail(&sdbg_host->host_list, &sdebug_host_list);
        spin_unlock(&sdebug_host_list_lock);

        sdbg_host->dev.bus = &pseudo_lld_bus;
        sdbg_host->dev.parent = pseudo_primary;
        sdbg_host->dev.release = &sdebug_release_adapter;
        dev_set_name(&sdbg_host->dev, "adapter%d", scsi_debug_add_host);

        error = device_register(&sdbg_host->dev);

        if (error)
		goto clean;

	++scsi_debug_add_host;
        return error;

clean:
	list_for_each_entry_safe(sdbg_devinfo, tmp, &sdbg_host->dev_info_list,
				 dev_list) {
		list_del(&sdbg_devinfo->dev_list);
		kfree(sdbg_devinfo);
	}

	kfree(sdbg_host);
        return error;
}

static void sdebug_remove_adapter(void)
{
        struct sdebug_host_info * sdbg_host = NULL;

        spin_lock(&sdebug_host_list_lock);
        if (!list_empty(&sdebug_host_list)) {
                sdbg_host = list_entry(sdebug_host_list.prev,
                                       struct sdebug_host_info, host_list);
		list_del(&sdbg_host->host_list);
	}
        spin_unlock(&sdebug_host_list_lock);

	if (!sdbg_host)
		return;

        device_unregister(&sdbg_host->dev);
        --scsi_debug_add_host;
}

static int
scsi_debug_queuecommand(struct scsi_cmnd *SCpnt)
{
	unsigned char *cmd = SCpnt->cmnd;
	int len, k;
	unsigned int num;
	unsigned long long lba;
	u32 ei_lba;
	int errsts = 0;
	int target = SCpnt->device->id;
	struct sdebug_dev_info *devip = NULL;
	int inj_recovered = 0;
	int inj_transport = 0;
	int inj_dif = 0;
	int inj_dix = 0;
	int inj_short = 0;
	int delay_override = 0;
	int unmap = 0;

	scsi_set_resid(SCpnt, 0);
	if ((SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) &&
	    !(SCSI_DEBUG_OPT_NO_CDB_NOISE & scsi_debug_opts)) {
		char b[120];
		int n;

		len = SCpnt->cmd_len;
		if (len > 32)
			strcpy(b, "too long, over 32 bytes");
		else {
			for (k = 0, n = 0; k < len; ++k)
				n += scnprintf(b + n, sizeof(b) - n, "%02x ",
					       (unsigned int)cmd[k]);
		}
		sdev_printk(KERN_INFO, SCpnt->device, "%s: cmd %s\n", my_name,
			    b);
	}

	if ((SCpnt->device->lun >= scsi_debug_max_luns) &&
	    (SCpnt->device->lun != SAM2_WLUN_REPORT_LUNS))
		return schedule_resp(SCpnt, NULL, DID_NO_CONNECT << 16, 0);
	devip = devInfoReg(SCpnt->device);
	if (NULL == devip)
		return schedule_resp(SCpnt, NULL, DID_NO_CONNECT << 16, 0);

	if ((scsi_debug_every_nth != 0) &&
	    (atomic_inc_return(&sdebug_cmnd_count) >=
	     abs(scsi_debug_every_nth))) {
		atomic_set(&sdebug_cmnd_count, 0);
		if (scsi_debug_every_nth < -1)
			scsi_debug_every_nth = -1;
		if (SCSI_DEBUG_OPT_TIMEOUT & scsi_debug_opts)
			return 0; /* ignore command causing timeout */
		else if (SCSI_DEBUG_OPT_MAC_TIMEOUT & scsi_debug_opts &&
			 scsi_medium_access_command(SCpnt))
			return 0; /* time out reads and writes */
		else if (SCSI_DEBUG_OPT_RECOVERED_ERR & scsi_debug_opts)
			inj_recovered = 1; /* to reads and writes below */
		else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & scsi_debug_opts)
			inj_transport = 1; /* to reads and writes below */
		else if (SCSI_DEBUG_OPT_DIF_ERR & scsi_debug_opts)
			inj_dif = 1; /* to reads and writes below */
		else if (SCSI_DEBUG_OPT_DIX_ERR & scsi_debug_opts)
			inj_dix = 1; /* to reads and writes below */
		else if (SCSI_DEBUG_OPT_SHORT_TRANSFER & scsi_debug_opts)
			inj_short = 1;
	}

	if (devip->wlun) {
		switch (*cmd) {
		case INQUIRY:
		case REQUEST_SENSE:
		case TEST_UNIT_READY:
		case REPORT_LUNS:
			break;  /* only allowable wlun commands */
		default:
			if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
				printk(KERN_INFO "scsi_debug: Opcode: 0x%x "
				       "not supported for wlun\n", *cmd);
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_OPCODE, 0);
			errsts = check_condition_result;
			return schedule_resp(SCpnt, devip, errsts, 0);
		}
	}

	switch (*cmd) {
	case INQUIRY:     /* mandatory, ignore unit attention */
		delay_override = 1;
		errsts = resp_inquiry(SCpnt, target, devip);
		break;
	case REQUEST_SENSE:	/* mandatory, ignore unit attention */
		delay_override = 1;
		errsts = resp_requests(SCpnt, devip);
		break;
	case REZERO_UNIT:	/* actually this is REWIND for SSC */
	case START_STOP:
		errsts = resp_start_stop(SCpnt, devip);
		break;
	case ALLOW_MEDIUM_REMOVAL:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		if (errsts)
			break;
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			printk(KERN_INFO "scsi_debug: Medium removal %s\n",
			       cmd[4] ? "inhibited" : "enabled");
		break;
	case SEND_DIAGNOSTIC:     /* mandatory */
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case TEST_UNIT_READY:     /* mandatory */
		/* delay_override = 1; */
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		break;
	case RESERVE:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case RESERVE_10:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case RELEASE:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case RELEASE_10:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case READ_CAPACITY:
		errsts = resp_readcap(SCpnt, devip);
		break;
	case SERVICE_ACTION_IN:
		if (cmd[1] == SAI_READ_CAPACITY_16)
			errsts = resp_readcap16(SCpnt, devip);
		else if (cmd[1] == SAI_GET_LBA_STATUS) {

			if (scsi_debug_lbp() == 0) {
				mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
						INVALID_COMMAND_OPCODE, 0);
				errsts = check_condition_result;
			} else
				errsts = resp_get_lba_status(SCpnt, devip);
		} else {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_OPCODE, 0);
			errsts = check_condition_result;
		}
		break;
	case MAINTENANCE_IN:
		if (MI_REPORT_TARGET_PGS != cmd[1]) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_OPCODE, 0);
			errsts = check_condition_result;
			break;
		}
		errsts = resp_report_tgtpgs(SCpnt, devip);
		break;
	case READ_16:
	case READ_12:
	case READ_10:
		/* READ{10,12,16} and DIF Type 2 are natural enemies */
		if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
		    cmd[1] & 0xe0) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_COMMAND_OPCODE, 0);
			errsts = check_condition_result;
			break;
		}

		if ((scsi_debug_dif == SD_DIF_TYPE1_PROTECTION ||
		     scsi_debug_dif == SD_DIF_TYPE3_PROTECTION) &&
		    (cmd[1] & 0xe0) == 0)
			printk(KERN_ERR "Unprotected RD/WR to DIF device\n");

		/* fall through */
	case READ_6:
read:
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		if (errsts)
			break;
		if (scsi_debug_fake_rw)
			break;
		get_data_transfer_info(cmd, &lba, &num, &ei_lba);

		if (inj_short)
			num /= 2;

		errsts = resp_read(SCpnt, lba, num, ei_lba);
		if (inj_recovered && (0 == errsts)) {
			mk_sense_buffer(SCpnt, RECOVERED_ERROR,
					THRESHOLD_EXCEEDED, 0);
			errsts = check_condition_result;
		} else if (inj_transport && (0 == errsts)) {
			mk_sense_buffer(SCpnt, ABORTED_COMMAND,
					TRANSPORT_PROBLEM, ACK_NAK_TO);
			errsts = check_condition_result;
		} else if (inj_dif && (0 == errsts)) {
			/* Logical block guard check failed */
			mk_sense_buffer(SCpnt, ABORTED_COMMAND, 0x10, 1);
			errsts = illegal_condition_result;
		} else if (inj_dix && (0 == errsts)) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST, 0x10, 1);
			errsts = illegal_condition_result;
		}
		break;
	case REPORT_LUNS:	/* mandatory, ignore unit attention */
		delay_override = 1;
		errsts = resp_report_luns(SCpnt, devip);
		break;
	case VERIFY:		/* 10 byte SBC-2 command */
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		break;
	case WRITE_16:
	case WRITE_12:
	case WRITE_10:
		/* WRITE{10,12,16} and DIF Type 2 are natural enemies */
		if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
		    cmd[1] & 0xe0) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_COMMAND_OPCODE, 0);
			errsts = check_condition_result;
			break;
		}

		if ((scsi_debug_dif == SD_DIF_TYPE1_PROTECTION ||
		     scsi_debug_dif == SD_DIF_TYPE3_PROTECTION) &&
		    (cmd[1] & 0xe0) == 0)
			printk(KERN_ERR "Unprotected RD/WR to DIF device\n");

		/* fall through */
	case WRITE_6:
write:
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		if (errsts)
			break;
		if (scsi_debug_fake_rw)
			break;
		get_data_transfer_info(cmd, &lba, &num, &ei_lba);
		errsts = resp_write(SCpnt, lba, num, ei_lba);
		if (inj_recovered && (0 == errsts)) {
			mk_sense_buffer(SCpnt, RECOVERED_ERROR,
					THRESHOLD_EXCEEDED, 0);
			errsts = check_condition_result;
		} else if (inj_dif && (0 == errsts)) {
			mk_sense_buffer(SCpnt, ABORTED_COMMAND, 0x10, 1);
			errsts = illegal_condition_result;
		} else if (inj_dix && (0 == errsts)) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST, 0x10, 1);
			errsts = illegal_condition_result;
		}
		break;
	case WRITE_SAME_16:
	case WRITE_SAME:
		if (cmd[1] & 0x8) {
			if ((*cmd == WRITE_SAME_16 && scsi_debug_lbpws == 0) ||
			    (*cmd == WRITE_SAME && scsi_debug_lbpws10 == 0)) {
				mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
						INVALID_FIELD_IN_CDB, 0);
				errsts = check_condition_result;
			} else
				unmap = 1;
		}
		if (errsts)
			break;
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		if (errsts)
			break;
		if (scsi_debug_fake_rw)
			break;
		get_data_transfer_info(cmd, &lba, &num, &ei_lba);
		errsts = resp_write_same(SCpnt, lba, num, ei_lba, unmap);
		break;
	case UNMAP:
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		if (errsts)
			break;
		if (scsi_debug_fake_rw)
			break;

		if (scsi_debug_unmap_max_desc == 0 || scsi_debug_lbpu == 0) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_COMMAND_OPCODE, 0);
			errsts = check_condition_result;
		} else
			errsts = resp_unmap(SCpnt, devip);
		break;
	case MODE_SENSE:
	case MODE_SENSE_10:
		errsts = resp_mode_sense(SCpnt, target, devip);
		break;
	case MODE_SELECT:
		errsts = resp_mode_select(SCpnt, 1, devip);
		break;
	case MODE_SELECT_10:
		errsts = resp_mode_select(SCpnt, 0, devip);
		break;
	case LOG_SENSE:
		errsts = resp_log_sense(SCpnt, devip);
		break;
	case SYNCHRONIZE_CACHE:
		delay_override = 1;
		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		break;
	case WRITE_BUFFER:
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		break;
	case XDWRITEREAD_10:
		if (!scsi_bidi_cmnd(SCpnt)) {
			mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
					INVALID_FIELD_IN_CDB, 0);
			errsts = check_condition_result;
			break;
		}

		errsts = check_readiness(SCpnt, UAS_TUR, devip);
		if (errsts)
			break;
		if (scsi_debug_fake_rw)
			break;
		get_data_transfer_info(cmd, &lba, &num, &ei_lba);
		errsts = resp_read(SCpnt, lba, num, ei_lba);
		if (errsts)
			break;
		errsts = resp_write(SCpnt, lba, num, ei_lba);
		if (errsts)
			break;
		errsts = resp_xdwriteread(SCpnt, lba, num, devip);
		break;
	case VARIABLE_LENGTH_CMD:
		if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION) {

			if ((cmd[10] & 0xe0) == 0)
				printk(KERN_ERR
				       "Unprotected RD/WR to DIF device\n");

			if (cmd[9] == READ_32) {
				BUG_ON(SCpnt->cmd_len < 32);
				goto read;
			}

			if (cmd[9] == WRITE_32) {
				BUG_ON(SCpnt->cmd_len < 32);
				goto write;
			}
		}

		mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
				INVALID_FIELD_IN_CDB, 0);
		errsts = check_condition_result;
		break;
	case 0x85:
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			sdev_printk(KERN_INFO, SCpnt->device,
			"%s: ATA PASS-THROUGH(16) not supported\n", my_name);
		mk_sense_buffer(SCpnt, ILLEGAL_REQUEST,
				INVALID_OPCODE, 0);
		errsts = check_condition_result;
		break;
	default:
		if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
			sdev_printk(KERN_INFO, SCpnt->device,
				    "%s: Opcode: 0x%x not supported\n",
				    my_name, *cmd);
		errsts = check_readiness(SCpnt, UAS_ONLY, devip);
		if (errsts)
			break;	/* Unit attention takes precedence */
		mk_sense_buffer(SCpnt, ILLEGAL_REQUEST, INVALID_OPCODE, 0);
		errsts = check_condition_result;
		break;
	}
	return schedule_resp(SCpnt, devip, errsts,
			     (delay_override ? 0 : scsi_debug_delay));
}

static int
sdebug_queuecommand_lock_or_not(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
	if (scsi_debug_host_lock) {
		unsigned long iflags;
		int rc;

		spin_lock_irqsave(shost->host_lock, iflags);
		rc = scsi_debug_queuecommand(cmd);
		spin_unlock_irqrestore(shost->host_lock, iflags);
		return rc;
	} else
		return scsi_debug_queuecommand(cmd);
}

static int
sdebug_change_qdepth(struct scsi_device *sdev, int qdepth, int reason)
{
	int num_in_q = 0;
	int bad = 0;
	unsigned long iflags;
	struct sdebug_dev_info *devip;

	spin_lock_irqsave(&queued_arr_lock, iflags);
	devip = (struct sdebug_dev_info *)sdev->hostdata;
	if (NULL == devip) {
		spin_unlock_irqrestore(&queued_arr_lock, iflags);
		return	-ENODEV;
	}
	num_in_q = atomic_read(&devip->num_in_q);
	spin_unlock_irqrestore(&queued_arr_lock, iflags);
	if (reason == SCSI_QDEPTH_DEFAULT || reason == SCSI_QDEPTH_RAMP_UP) {
		if (qdepth < 1)
			qdepth = 1;
		/* allow to exceed max host queued_arr elements for testing */
		if (qdepth > SCSI_DEBUG_CANQUEUE + 10)
			qdepth = SCSI_DEBUG_CANQUEUE + 10;
		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), qdepth);
	} else if (reason == SCSI_QDEPTH_QFULL)
		scsi_track_queue_full(sdev, qdepth);
	else
		bad = 1;
	if (bad)
		sdev_printk(KERN_WARNING, sdev,
			    "%s: unknown reason=0x%x\n", __func__, reason);
	if (SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts) {
		if (SCSI_QDEPTH_QFULL == reason)
			sdev_printk(KERN_INFO, sdev,
			    "%s: -> %d, num_in_q=%d, reason: queue full\n",
				    __func__, qdepth, num_in_q);
		else {
			const char *cp;

			switch (reason) {
			case SCSI_QDEPTH_DEFAULT:
				cp = "default (sysfs ?)";
				break;
			case SCSI_QDEPTH_RAMP_UP:
				cp = "ramp up";
				break;
			default:
				cp = "unknown";
				break;
			}
			sdev_printk(KERN_INFO, sdev,
				    "%s: qdepth=%d, num_in_q=%d, reason: %s\n",
				    __func__, qdepth, num_in_q, cp);
		}
	}
	return sdev->queue_depth;
}

static int
sdebug_change_qtype(struct scsi_device *sdev, int qtype)
{
	if (sdev->tagged_supported) {
		scsi_set_tag_type(sdev, qtype);
		if (qtype)
			scsi_activate_tcq(sdev, sdev->queue_depth);
		else
			scsi_deactivate_tcq(sdev, sdev->queue_depth);
	} else
		qtype = 0;
	if (SCSI_DEBUG_OPT_Q_NOISE & scsi_debug_opts) {
		const char *cp;

		switch (qtype) {
		case 0:
			cp = "untagged";
			break;
		case MSG_SIMPLE_TAG:
			cp = "simple tags";
			break;
		case MSG_ORDERED_TAG:
			cp = "ordered tags";
			break;
		default:
			cp = "unknown";
			break;
		}
		sdev_printk(KERN_INFO, sdev, "%s: to %s\n", __func__, cp);
	}
	return qtype;
}

static struct scsi_host_template sdebug_driver_template = {
	.show_info =		scsi_debug_show_info,
	.write_info =		scsi_debug_write_info,
	.proc_name =		sdebug_proc_name,
	.name =			"SCSI DEBUG",
	.info =			scsi_debug_info,
	.slave_alloc =		scsi_debug_slave_alloc,
	.slave_configure =	scsi_debug_slave_configure,
	.slave_destroy =	scsi_debug_slave_destroy,
	.ioctl =		scsi_debug_ioctl,
	.queuecommand =		sdebug_queuecommand_lock_or_not,
	.change_queue_depth =	sdebug_change_qdepth,
	.change_queue_type =	sdebug_change_qtype,
	.eh_abort_handler =	scsi_debug_abort,
	.eh_device_reset_handler = scsi_debug_device_reset,
	.eh_target_reset_handler = scsi_debug_target_reset,
	.eh_bus_reset_handler = scsi_debug_bus_reset,
	.eh_host_reset_handler = scsi_debug_host_reset,
	.can_queue =		SCSI_DEBUG_CANQUEUE,
	.this_id =		7,
	.sg_tablesize =		SCSI_MAX_SG_CHAIN_SEGMENTS,
	.cmd_per_lun =		DEF_CMD_PER_LUN,
	.max_sectors =		-1U,
	.use_clustering = 	DISABLE_CLUSTERING,
	.module =		THIS_MODULE,
};

static int sdebug_driver_probe(struct device * dev)
{
        int error = 0;
        struct sdebug_host_info *sdbg_host;
        struct Scsi_Host *hpnt;
	int host_prot;

	sdbg_host = to_sdebug_host(dev);

	sdebug_driver_template.can_queue = scsi_debug_max_queue;
	if (scsi_debug_clustering)
		sdebug_driver_template.use_clustering = ENABLE_CLUSTERING;
	hpnt = scsi_host_alloc(&sdebug_driver_template, sizeof(sdbg_host));
	if (NULL == hpnt) {
		printk(KERN_ERR "%s: scsi_register failed\n", __func__);
		error = -ENODEV;
		return error;
	}

        sdbg_host->shost = hpnt;
	*((struct sdebug_host_info **)hpnt->hostdata) = sdbg_host;
	if ((hpnt->this_id >= 0) && (scsi_debug_num_tgts > hpnt->this_id))
		hpnt->max_id = scsi_debug_num_tgts + 1;
	else
		hpnt->max_id = scsi_debug_num_tgts;
	hpnt->max_lun = SAM2_WLUN_REPORT_LUNS;	/* = scsi_debug_max_luns; */

	host_prot = 0;

	switch (scsi_debug_dif) {

	case SD_DIF_TYPE1_PROTECTION:
		host_prot = SHOST_DIF_TYPE1_PROTECTION;
		if (scsi_debug_dix)
			host_prot |= SHOST_DIX_TYPE1_PROTECTION;
		break;

	case SD_DIF_TYPE2_PROTECTION:
		host_prot = SHOST_DIF_TYPE2_PROTECTION;
		if (scsi_debug_dix)
			host_prot |= SHOST_DIX_TYPE2_PROTECTION;
		break;

	case SD_DIF_TYPE3_PROTECTION:
		host_prot = SHOST_DIF_TYPE3_PROTECTION;
		if (scsi_debug_dix)
			host_prot |= SHOST_DIX_TYPE3_PROTECTION;
		break;

	default:
		if (scsi_debug_dix)
			host_prot |= SHOST_DIX_TYPE0_PROTECTION;
		break;
	}

	scsi_host_set_prot(hpnt, host_prot);

	printk(KERN_INFO "scsi_debug: host protection%s%s%s%s%s%s%s\n",
	       (host_prot & SHOST_DIF_TYPE1_PROTECTION) ? " DIF1" : "",
	       (host_prot & SHOST_DIF_TYPE2_PROTECTION) ? " DIF2" : "",
	       (host_prot & SHOST_DIF_TYPE3_PROTECTION) ? " DIF3" : "",
	       (host_prot & SHOST_DIX_TYPE0_PROTECTION) ? " DIX0" : "",
	       (host_prot & SHOST_DIX_TYPE1_PROTECTION) ? " DIX1" : "",
	       (host_prot & SHOST_DIX_TYPE2_PROTECTION) ? " DIX2" : "",
	       (host_prot & SHOST_DIX_TYPE3_PROTECTION) ? " DIX3" : "");

	if (scsi_debug_guard == 1)
		scsi_host_set_guard(hpnt, SHOST_DIX_GUARD_IP);
	else
		scsi_host_set_guard(hpnt, SHOST_DIX_GUARD_CRC);

        error = scsi_add_host(hpnt, &sdbg_host->dev);
        if (error) {
                printk(KERN_ERR "%s: scsi_add_host failed\n", __func__);
                error = -ENODEV;
		scsi_host_put(hpnt);
        } else
		scsi_scan_host(hpnt);

	return error;
}

static int sdebug_driver_remove(struct device * dev)
{
        struct sdebug_host_info *sdbg_host;
	struct sdebug_dev_info *sdbg_devinfo, *tmp;

	sdbg_host = to_sdebug_host(dev);

	if (!sdbg_host) {
		printk(KERN_ERR "%s: Unable to locate host info\n",
		       __func__);
		return -ENODEV;
	}

        scsi_remove_host(sdbg_host->shost);

	list_for_each_entry_safe(sdbg_devinfo, tmp, &sdbg_host->dev_info_list,
				 dev_list) {
                list_del(&sdbg_devinfo->dev_list);
                kfree(sdbg_devinfo);
        }

        scsi_host_put(sdbg_host->shost);
        return 0;
}

static int pseudo_lld_bus_match(struct device *dev,
				struct device_driver *dev_driver)
{
	return 1;
}

static struct bus_type pseudo_lld_bus = {
	.name = "pseudo",
	.match = pseudo_lld_bus_match,
	.probe = sdebug_driver_probe,
	.remove = sdebug_driver_remove,
	.drv_groups = sdebug_drv_groups,
};