/*
 * 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 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 *
 * Copyright (C) 2001 - 2018 Douglas Gilbert
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 *  For documentation see http://sg.danny.cz/sg/sdebug26.html
 *
 */


#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/jiffies.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 <linux/uuid.h>
#include <linux/t10-pi.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"

/* make sure inq_product_rev string corresponds to this version */
#define SDEBUG_VERSION "0188"   /* format to fit INQUIRY revision field */
static const char *sdebug_version_date = "20180128";

#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 LBA_OUT_OF_RANGE 0x21
#define INVALID_FIELD_IN_CDB 0x24
#define INVALID_FIELD_IN_PARAM_LIST 0x26
#define UA_RESET_ASC 0x29
#define UA_CHANGED_ASC 0x2a
#define TARGET_CHANGED_ASC 0x3f
#define LUNS_CHANGED_ASCQ 0x0e
#define INSUFF_RES_ASC 0x55
#define INSUFF_RES_ASCQ 0x3
#define POWER_ON_RESET_ASCQ 0x0
#define BUS_RESET_ASCQ 0x2      /* scsi bus reset occurred */
#define MODE_CHANGED_ASCQ 0x1   /* mode parameters changed */
#define CAPACITY_CHANGED_ASCQ 0x9
#define SAVING_PARAMS_UNSUP 0x39
#define TRANSPORT_PROBLEM 0x4b
#define THRESHOLD_EXCEEDED 0x5d
#define LOW_POWER_COND_ON 0x5e
#define MISCOMPARE_VERIFY_ASC 0x1d
#define MICROCODE_CHANGED_ASCQ 0x1      /* with TARGET_CHANGED_ASC */
#define MICROCODE_CHANGED_WO_RESET_ASCQ 0x16
#define WRITE_ERROR_ASC 0xc

/* 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_CDB_LEN 10
#define DEF_JDELAY   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 1024
#define DEF_PHYSBLK_EXP 0
#define DEF_OPT_XFERLEN_EXP 0
#define DEF_PTYPE   TYPE_DISK
#define DEF_REMOVABLE false
#define DEF_SCSI_LEVEL   7    /* INQUIRY, byte2 [6->SPC-4; 7->SPC-5] */
#define DEF_SECTOR_SIZE 512
#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 DEF_STRICT 0
#define DEF_STATISTICS false
#define DEF_SUBMIT_QUEUES 1
#define DEF_UUID_CTL 0
#define JDELAY_OVERRIDDEN -9999

#define SDEBUG_LUN_0_VAL 0

/* bit mask values for sdebug_opts */
#define SDEBUG_OPT_NOISE                1
#define SDEBUG_OPT_MEDIUM_ERR           2
#define SDEBUG_OPT_TIMEOUT              4
#define SDEBUG_OPT_RECOVERED_ERR        8
#define SDEBUG_OPT_TRANSPORT_ERR        16
#define SDEBUG_OPT_DIF_ERR              32
#define SDEBUG_OPT_DIX_ERR              64
#define SDEBUG_OPT_MAC_TIMEOUT          128
#define SDEBUG_OPT_SHORT_TRANSFER       0x100
#define SDEBUG_OPT_Q_NOISE              0x200
#define SDEBUG_OPT_ALL_TSF              0x400
#define SDEBUG_OPT_RARE_TSF             0x800
#define SDEBUG_OPT_N_WCE                0x1000
#define SDEBUG_OPT_RESET_NOISE          0x2000
#define SDEBUG_OPT_NO_CDB_NOISE         0x4000
#define SDEBUG_OPT_HOST_BUSY            0x8000
#define SDEBUG_OPT_CMD_ABORT            0x10000
#define SDEBUG_OPT_ALL_NOISE (SDEBUG_OPT_NOISE | SDEBUG_OPT_Q_NOISE | \
                              SDEBUG_OPT_RESET_NOISE)
#define SDEBUG_OPT_ALL_INJECTING (SDEBUG_OPT_RECOVERED_ERR | \
                                  SDEBUG_OPT_TRANSPORT_ERR | \
                                  SDEBUG_OPT_DIF_ERR | SDEBUG_OPT_DIX_ERR | \
                                  SDEBUG_OPT_SHORT_TRANSFER | \
                                  SDEBUG_OPT_HOST_BUSY | \
                                  SDEBUG_OPT_CMD_ABORT)
/* When "every_nth" > 0 then modulo "every_nth" commands:
 *   - a missing response is simulated if SDEBUG_OPT_TIMEOUT is set
 *   - a RECOVERED_ERROR is simulated on successful read and write
 *     commands if SDEBUG_OPT_RECOVERED_ERR is set.
 *   - a TRANSPORT_ERROR is simulated on successful read and write
 *     commands if SDEBUG_OPT_TRANSPORT_ERR is set.
 *   - similarly for DIF_ERR, DIX_ERR, SHORT_TRANSFER, HOST_BUSY and
 *     CMD_ABORT
 *
 * When "every_nth" < 0 then after "- every_nth" commands the selected
 * error will be injected. The error will be injected on every subsequent
 * command until some other action occurs; for example, the user writing
 * a new value (other than -1 or 1) to every_nth:
 *      echo 0 > /sys/bus/pseudo/drivers/scsi_debug/every_nth
 */

/* 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_UA_CAPACITY_CHANGED 3
#define SDEBUG_UA_LUNS_CHANGED 4
#define SDEBUG_UA_MICROCODE_CHANGED 5   /* simulate firmware change */
#define SDEBUG_UA_MICROCODE_CHANGED_WO_RESET 6
#define SDEBUG_NUM_UAS 7

/* when 1==SDEBUG_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

/* SDEBUG_CANQUEUE is the maximum number of commands that can be queued
 * (for response) per submit queue at one time. Can be reduced by max_queue
 * option. Command responses are not queued when jdelay=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 SDEBUG_CANQUEUE .
 */
#define SDEBUG_CANQUEUE_WORDS  3        /* a WORD is bits in a long */
#define SDEBUG_CANQUEUE  (SDEBUG_CANQUEUE_WORDS * BITS_PER_LONG)
#define DEF_CMD_PER_LUN  255

#define F_D_IN                  1
#define F_D_OUT                 2
#define F_D_OUT_MAYBE           4       /* WRITE SAME, NDOB bit */
#define F_D_UNKN                8
#define F_RL_WLUN_OK            0x10
#define F_SKIP_UA               0x20
#define F_DELAY_OVERR           0x40
#define F_SA_LOW                0x80    /* cdb byte 1, bits 4 to 0 */
#define F_SA_HIGH               0x100   /* as used by variable length cdbs */
#define F_INV_OP                0x200
#define F_FAKE_RW               0x400
#define F_M_ACCESS              0x800   /* media access */
#define F_SSU_DELAY             0x1000
#define F_SYNC_DELAY            0x2000

#define FF_RESPOND (F_RL_WLUN_OK | F_SKIP_UA | F_DELAY_OVERR)
#define FF_MEDIA_IO (F_M_ACCESS | F_FAKE_RW)
#define FF_SA (F_SA_HIGH | F_SA_LOW)
#define F_LONG_DELAY            (F_SSU_DELAY | F_SYNC_DELAY)

#define SDEBUG_MAX_PARTS 4

#define SDEBUG_MAX_CMD_LEN 32


struct sdebug_dev_info {
        struct list_head dev_list;
        unsigned int channel;
        unsigned int target;
        u64 lun;
        uuid_t lu_name;
        struct sdebug_host_info *sdbg_host;
        unsigned long uas_bm[1];
        atomic_t num_in_q;
        atomic_t stopped;
        bool 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)

enum sdeb_defer_type {SDEB_DEFER_NONE = 0, SDEB_DEFER_HRT = 1,
                      SDEB_DEFER_WQ = 2};

struct sdebug_defer {
        struct hrtimer hrt;
        struct execute_work ew;
        int sqa_idx;    /* index of sdebug_queue array */
        int qc_idx;     /* index of sdebug_queued_cmd array within sqa_idx */
        int issuing_cpu;
        bool init_hrt;
        bool init_wq;
        bool aborted;   /* true when blk_abort_request() already called */
        enum sdeb_defer_type defer_t;
};

struct sdebug_queued_cmd {
        /* corresponding bit set in in_use_bm[] in owning struct sdebug_queue
         * instance indicates this slot is in use.
         */
        struct sdebug_defer *sd_dp;
        struct scsi_cmnd *a_cmnd;
        unsigned int inj_recovered:1;
        unsigned int inj_transport:1;
        unsigned int inj_dif:1;
        unsigned int inj_dix:1;
        unsigned int inj_short:1;
        unsigned int inj_host_busy:1;
        unsigned int inj_cmd_abort:1;
};

struct sdebug_queue {
        struct sdebug_queued_cmd qc_arr[SDEBUG_CANQUEUE];
        unsigned long in_use_bm[SDEBUG_CANQUEUE_WORDS];
        spinlock_t qc_lock;
        atomic_t blocked;       /* to temporarily stop more being queued */
};

static atomic_t sdebug_cmnd_count;   /* number of incoming commands */
static atomic_t sdebug_completions;  /* count of deferred completions */
static atomic_t sdebug_miss_cpus;    /* submission + completion cpus differ */
static atomic_t sdebug_a_tsf;        /* 'almost task set full' counter */

struct opcode_info_t {
        u8 num_attached;        /* 0 if this is it (i.e. a leaf); use 0xff */
                                /* for terminating element */
        u8 opcode;              /* if num_attached > 0, preferred */
        u16 sa;                 /* service action */
        u32 flags;              /* OR-ed set of SDEB_F_* */
        int (*pfp)(struct scsi_cmnd *, struct sdebug_dev_info *);
        const struct opcode_info_t *arrp;  /* num_attached elements or NULL */
        u8 len_mask[16];        /* len_mask[0]-->cdb_len, then mask for cdb */
                                /* 1 to min(cdb_len, 15); ignore cdb[15...] */
};

/* SCSI opcodes (first byte of cdb) of interest mapped onto these indexes */
enum sdeb_opcode_index {
        SDEB_I_INVALID_OPCODE = 0,
        SDEB_I_INQUIRY = 1,
        SDEB_I_REPORT_LUNS = 2,
        SDEB_I_REQUEST_SENSE = 3,
        SDEB_I_TEST_UNIT_READY = 4,
        SDEB_I_MODE_SENSE = 5,          /* 6, 10 */
        SDEB_I_MODE_SELECT = 6,         /* 6, 10 */
        SDEB_I_LOG_SENSE = 7,
        SDEB_I_READ_CAPACITY = 8,       /* 10; 16 is in SA_IN(16) */
        SDEB_I_READ = 9,                /* 6, 10, 12, 16 */
        SDEB_I_WRITE = 10,              /* 6, 10, 12, 16 */
        SDEB_I_START_STOP = 11,
        SDEB_I_SERV_ACT_IN_16 = 12,     /* add ...SERV_ACT_IN_12 if needed */
        SDEB_I_SERV_ACT_OUT_16 = 13,    /* add ...SERV_ACT_OUT_12 if needed */
        SDEB_I_MAINT_IN = 14,
        SDEB_I_MAINT_OUT = 15,
        SDEB_I_VERIFY = 16,             /* 10 only */
        SDEB_I_VARIABLE_LEN = 17,       /* READ(32), WRITE(32), WR_SCAT(32) */
        SDEB_I_RESERVE = 18,            /* 6, 10 */
        SDEB_I_RELEASE = 19,            /* 6, 10 */
        SDEB_I_ALLOW_REMOVAL = 20,      /* PREVENT ALLOW MEDIUM REMOVAL */
        SDEB_I_REZERO_UNIT = 21,        /* REWIND in SSC */
        SDEB_I_ATA_PT = 22,             /* 12, 16 */
        SDEB_I_SEND_DIAG = 23,
        SDEB_I_UNMAP = 24,
        SDEB_I_XDWRITEREAD = 25,        /* 10 only */
        SDEB_I_WRITE_BUFFER = 26,
        SDEB_I_WRITE_SAME = 27,         /* 10, 16 */
        SDEB_I_SYNC_CACHE = 28,         /* 10, 16 */
        SDEB_I_COMP_WRITE = 29,
        SDEB_I_LAST_ELEMENT = 30,       /* keep this last (previous + 1) */
};


static const unsigned char opcode_ind_arr[256] = {
/* 0x0; 0x0->0x1f: 6 byte cdbs */
        SDEB_I_TEST_UNIT_READY, SDEB_I_REZERO_UNIT, 0, SDEB_I_REQUEST_SENSE,
            0, 0, 0, 0,
        SDEB_I_READ, 0, SDEB_I_WRITE, 0, 0, 0, 0, 0,
        0, 0, SDEB_I_INQUIRY, 0, 0, SDEB_I_MODE_SELECT, SDEB_I_RESERVE,
            SDEB_I_RELEASE,
        0, 0, SDEB_I_MODE_SENSE, SDEB_I_START_STOP, 0, SDEB_I_SEND_DIAG,
            SDEB_I_ALLOW_REMOVAL, 0,
/* 0x20; 0x20->0x3f: 10 byte cdbs */
        0, 0, 0, 0, 0, SDEB_I_READ_CAPACITY, 0, 0,
        SDEB_I_READ, 0, SDEB_I_WRITE, 0, 0, 0, 0, SDEB_I_VERIFY,
        0, 0, 0, 0, 0, SDEB_I_SYNC_CACHE, 0, 0,
        0, 0, 0, SDEB_I_WRITE_BUFFER, 0, 0, 0, 0,
/* 0x40; 0x40->0x5f: 10 byte cdbs */
        0, SDEB_I_WRITE_SAME, SDEB_I_UNMAP, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, SDEB_I_LOG_SENSE, 0, 0,
        0, 0, 0, SDEB_I_XDWRITEREAD, 0, SDEB_I_MODE_SELECT, SDEB_I_RESERVE,
            SDEB_I_RELEASE,
        0, 0, SDEB_I_MODE_SENSE, 0, 0, 0, 0, 0,
/* 0x60; 0x60->0x7d are reserved, 0x7e is "extended cdb" */
        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, SDEB_I_VARIABLE_LEN,
/* 0x80; 0x80->0x9f: 16 byte cdbs */
        0, 0, 0, 0, 0, SDEB_I_ATA_PT, 0, 0,
        SDEB_I_READ, SDEB_I_COMP_WRITE, SDEB_I_WRITE, 0, 0, 0, 0, 0,
        0, SDEB_I_SYNC_CACHE, 0, SDEB_I_WRITE_SAME, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, SDEB_I_SERV_ACT_IN_16, SDEB_I_SERV_ACT_OUT_16,
/* 0xa0; 0xa0->0xbf: 12 byte cdbs */
        SDEB_I_REPORT_LUNS, SDEB_I_ATA_PT, 0, SDEB_I_MAINT_IN,
             SDEB_I_MAINT_OUT, 0, 0, 0,
        SDEB_I_READ, 0 /* SDEB_I_SERV_ACT_OUT_12 */, SDEB_I_WRITE,
             0 /* SDEB_I_SERV_ACT_IN_12 */, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
/* 0xc0; 0xc0->0xff: vendor specific */
        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,
};

/*
 * The following "response" functions return the SCSI mid-level's 4 byte
 * tuple-in-an-int. To handle commands with an IMMED bit, for a faster
 * command completion, they can mask their return value with
 * SDEG_RES_IMMED_MASK .
 */
#define SDEG_RES_IMMED_MASK 0x40000000

static int resp_inquiry(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_report_luns(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_requests(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_mode_sense(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_mode_select(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_log_sense(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_readcap(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_read_dt0(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_write_dt0(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_write_scat(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_start_stop(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_readcap16(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_get_lba_status(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_report_tgtpgs(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_unmap(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_rsup_opcodes(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_rsup_tmfs(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_write_same_10(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_write_same_16(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_xdwriteread_10(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_comp_write(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_write_buffer(struct scsi_cmnd *, struct sdebug_dev_info *);
static int resp_sync_cache(struct scsi_cmnd *, struct sdebug_dev_info *);

/*
 * The following are overflow arrays for cdbs that "hit" the same index in
 * the opcode_info_arr array. The most time sensitive (or commonly used) cdb
 * should be placed in opcode_info_arr[], the others should be placed here.
 */
static const struct opcode_info_t msense_iarr[] = {
        {0, 0x1a, 0, F_D_IN, NULL, NULL,
            {6,  0xe8, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

static const struct opcode_info_t mselect_iarr[] = {
        {0, 0x15, 0, F_D_OUT, NULL, NULL,
            {6,  0xf1, 0, 0, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

static const struct opcode_info_t read_iarr[] = {
        {0, 0x28, 0, F_D_IN | FF_MEDIA_IO, resp_read_dt0, NULL,/* READ(10) */
            {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7, 0, 0,
             0, 0, 0, 0} },
        {0, 0x8, 0, F_D_IN | FF_MEDIA_IO, resp_read_dt0, NULL, /* READ(6) */
            {6,  0xff, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0xa8, 0, F_D_IN | FF_MEDIA_IO, resp_read_dt0, NULL,/* READ(12) */
            {12,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xbf,
             0xc7, 0, 0, 0, 0} },
};

static const struct opcode_info_t write_iarr[] = {
        {0, 0x2a, 0, F_D_OUT | FF_MEDIA_IO, resp_write_dt0,  /* WRITE(10) */
            NULL, {10,  0xfb, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7,
                   0, 0, 0, 0, 0, 0} },
        {0, 0xa, 0, F_D_OUT | FF_MEDIA_IO, resp_write_dt0,   /* WRITE(6) */
            NULL, {6,  0xff, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0,
                   0, 0, 0} },
        {0, 0xaa, 0, F_D_OUT | FF_MEDIA_IO, resp_write_dt0,  /* WRITE(12) */
            NULL, {12,  0xfb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                   0xbf, 0xc7, 0, 0, 0, 0} },
};

static const struct opcode_info_t sa_in_16_iarr[] = {
        {0, 0x9e, 0x12, F_SA_LOW | F_D_IN, resp_get_lba_status, NULL,
            {16,  0x12, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
             0xff, 0xff, 0xff, 0, 0xc7} },      /* GET LBA STATUS(16) */
};

static const struct opcode_info_t vl_iarr[] = { /* VARIABLE LENGTH */
        {0, 0x7f, 0xb, F_SA_HIGH | F_D_OUT | FF_MEDIA_IO, resp_write_dt0,
            NULL, {32,  0xc7, 0, 0, 0, 0, 0x3f, 0x18, 0x0, 0xb, 0xfa,
                   0, 0xff, 0xff, 0xff, 0xff} },        /* WRITE(32) */
        {0, 0x7f, 0x11, F_SA_HIGH | F_D_OUT | FF_MEDIA_IO, resp_write_scat,
            NULL, {32,  0xc7, 0, 0, 0, 0, 0x3f, 0x18, 0x0, 0x11, 0xf8,
                   0, 0xff, 0xff, 0x0, 0x0} },  /* WRITE SCATTERED(32) */
};

static const struct opcode_info_t maint_in_iarr[] = {   /* MAINT IN */
        {0, 0xa3, 0xc, F_SA_LOW | F_D_IN, resp_rsup_opcodes, NULL,
            {12,  0xc, 0x87, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0,
             0xc7, 0, 0, 0, 0} }, /* REPORT SUPPORTED OPERATION CODES */
        {0, 0xa3, 0xd, F_SA_LOW | F_D_IN, resp_rsup_tmfs, NULL,
            {12,  0xd, 0x80, 0, 0, 0, 0xff, 0xff, 0xff, 0xff, 0, 0xc7, 0, 0,
             0, 0} },   /* REPORTED SUPPORTED TASK MANAGEMENT FUNCTIONS */
};

static const struct opcode_info_t write_same_iarr[] = {
        {0, 0x93, 0, F_D_OUT_MAYBE | FF_MEDIA_IO, resp_write_same_16, NULL,
            {16,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
             0xff, 0xff, 0xff, 0x3f, 0xc7} },           /* WRITE SAME(16) */
};

static const struct opcode_info_t reserve_iarr[] = {
        {0, 0x16, 0, F_D_OUT, NULL, NULL,               /* RESERVE(6) */
            {6,  0x1f, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

static const struct opcode_info_t release_iarr[] = {
        {0, 0x17, 0, F_D_OUT, NULL, NULL,               /* RELEASE(6) */
            {6,  0x1f, 0xff, 0, 0, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

static const struct opcode_info_t sync_cache_iarr[] = {
        {0, 0x91, 0, F_SYNC_DELAY | F_M_ACCESS, resp_sync_cache, NULL,
            {16,  0x6, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
             0xff, 0xff, 0xff, 0xff, 0x3f, 0xc7} },     /* SYNC_CACHE (16) */
};


/* This array is accessed via SDEB_I_* values. Make sure all are mapped,
 * plus the terminating elements for logic that scans this table such as
 * REPORT SUPPORTED OPERATION CODES. */
static const struct opcode_info_t opcode_info_arr[SDEB_I_LAST_ELEMENT + 1] = {
/* 0 */
        {0, 0, 0, F_INV_OP | FF_RESPOND, NULL, NULL,    /* unknown opcodes */
            {0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x12, 0, FF_RESPOND | F_D_IN, resp_inquiry, NULL, /* INQUIRY */
            {6,  0xe3, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0xa0, 0, FF_RESPOND | F_D_IN, resp_report_luns, NULL,
            {12,  0xe3, 0xff, 0, 0, 0, 0xff, 0xff, 0xff, 0xff, 0, 0xc7, 0, 0,
             0, 0} },                                   /* REPORT LUNS */
        {0, 0x3, 0, FF_RESPOND | F_D_IN, resp_requests, NULL,
            {6,  0xe1, 0, 0, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x0, 0, F_M_ACCESS | F_RL_WLUN_OK, NULL, NULL,/* TEST UNIT READY */
            {6,  0, 0, 0, 0, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
/* 5 */
        {ARRAY_SIZE(msense_iarr), 0x5a, 0, F_D_IN,      /* MODE SENSE(10) */
            resp_mode_sense, msense_iarr, {10,  0xf8, 0xff, 0xff, 0, 0, 0,
                0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0} },
        {ARRAY_SIZE(mselect_iarr), 0x55, 0, F_D_OUT,    /* MODE SELECT(10) */
            resp_mode_select, mselect_iarr, {10,  0xf1, 0, 0, 0, 0, 0, 0xff,
                0xff, 0xc7, 0, 0, 0, 0, 0, 0} },
        {0, 0x4d, 0, F_D_IN, resp_log_sense, NULL,      /* LOG SENSE */
            {10,  0xe3, 0xff, 0xff, 0, 0xff, 0xff, 0xff, 0xff, 0xc7, 0, 0, 0,
             0, 0, 0} },
        {0, 0x25, 0, F_D_IN, resp_readcap, NULL,    /* READ CAPACITY(10) */
            {10,  0xe1, 0xff, 0xff, 0xff, 0xff, 0, 0, 0x1, 0xc7, 0, 0, 0, 0,
             0, 0} },
        {ARRAY_SIZE(read_iarr), 0x88, 0, F_D_IN | FF_MEDIA_IO, /* READ(16) */
            resp_read_dt0, read_iarr, {16,  0xfe, 0xff, 0xff, 0xff, 0xff,
            0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7} },
/* 10 */
        {ARRAY_SIZE(write_iarr), 0x8a, 0, F_D_OUT | FF_MEDIA_IO,
            resp_write_dt0, write_iarr,                 /* WRITE(16) */
                {16,  0xfa, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7} },
        {0, 0x1b, 0, F_SSU_DELAY, resp_start_stop, NULL,/* START STOP UNIT */
            {6,  0x1, 0, 0xf, 0xf7, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {ARRAY_SIZE(sa_in_16_iarr), 0x9e, 0x10, F_SA_LOW | F_D_IN,
            resp_readcap16, sa_in_16_iarr, /* SA_IN(16), READ CAPACITY(16) */
                {16,  0x10, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                 0xff, 0xff, 0xff, 0xff, 0x1, 0xc7} },
        {0, 0x9f, 0x12, F_SA_LOW | F_D_OUT | FF_MEDIA_IO, resp_write_scat,
            NULL, {16,  0x12, 0xf9, 0x0, 0xff, 0xff, 0, 0, 0xff, 0xff, 0xff,
            0xff, 0xff, 0xff, 0xff, 0xc7} },  /* SA_OUT(16), WRITE SCAT(16) */
        {ARRAY_SIZE(maint_in_iarr), 0xa3, 0xa, F_SA_LOW | F_D_IN,
            resp_report_tgtpgs, /* MAINT IN, REPORT TARGET PORT GROUPS */
                maint_in_iarr, {12,  0xea, 0, 0, 0, 0, 0xff, 0xff, 0xff,
                                0xff, 0, 0xc7, 0, 0, 0, 0} },
/* 15 */
        {0, 0, 0, F_INV_OP | FF_RESPOND, NULL, NULL, /* MAINT OUT */
            {0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x2f, 0, F_D_OUT_MAYBE | FF_MEDIA_IO, NULL, NULL, /* VERIFY(10) */
            {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7,
             0, 0, 0, 0, 0, 0} },
        {ARRAY_SIZE(vl_iarr), 0x7f, 0x9, F_SA_HIGH | F_D_IN | FF_MEDIA_IO,
            resp_read_dt0, vl_iarr,     /* VARIABLE LENGTH, READ(32) */
            {32,  0xc7, 0, 0, 0, 0, 0x3f, 0x18, 0x0, 0x9, 0xfe, 0, 0xff, 0xff,
             0xff, 0xff} },
        {ARRAY_SIZE(reserve_iarr), 0x56, 0, F_D_OUT,
            NULL, reserve_iarr, /* RESERVE(10) <no response function> */
            {10,  0xff, 0xff, 0xff, 0, 0, 0, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0,
             0} },
        {ARRAY_SIZE(release_iarr), 0x57, 0, F_D_OUT,
            NULL, release_iarr, /* RELEASE(10) <no response function> */
            {10,  0x13, 0xff, 0xff, 0, 0, 0, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0,
             0} },
/* 20 */
        {0, 0x1e, 0, 0, NULL, NULL, /* ALLOW REMOVAL */
            {6,  0, 0, 0, 0x3, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x1, 0, 0, resp_start_stop, NULL, /* REWIND ?? */
            {6,  0x1, 0, 0, 0, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0, 0, F_INV_OP | FF_RESPOND, NULL, NULL, /* ATA_PT */
            {0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x1d, F_D_OUT, 0, NULL, NULL,       /* SEND DIAGNOSTIC */
            {6,  0xf7, 0, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
        {0, 0x42, 0, F_D_OUT | FF_MEDIA_IO, resp_unmap, NULL, /* UNMAP */
            {10,  0x1, 0, 0, 0, 0, 0x3f, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0} },
/* 25 */
        {0, 0x53, 0, F_D_IN | F_D_OUT | FF_MEDIA_IO, resp_xdwriteread_10,
            NULL, {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7,
                   0, 0, 0, 0, 0, 0} },         /* XDWRITEREAD(10) */
        {0, 0x3b, 0, F_D_OUT_MAYBE, resp_write_buffer, NULL,
            {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7, 0, 0,
             0, 0, 0, 0} },                     /* WRITE_BUFFER */
        {ARRAY_SIZE(write_same_iarr), 0x41, 0, F_D_OUT_MAYBE | FF_MEDIA_IO,
            resp_write_same_10, write_same_iarr,        /* WRITE SAME(10) */
                {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7, 0,
                 0, 0, 0, 0, 0} },
        {ARRAY_SIZE(sync_cache_iarr), 0x35, 0, F_SYNC_DELAY | F_M_ACCESS,
            resp_sync_cache, sync_cache_iarr,
            {10,  0x7, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7, 0, 0,
             0, 0, 0, 0} },                     /* SYNC_CACHE (10) */
        {0, 0x89, 0, F_D_OUT | FF_MEDIA_IO, resp_comp_write, NULL,
            {16,  0xf8, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0,
             0, 0xff, 0x3f, 0xc7} },            /* COMPARE AND WRITE */

/* 30 */
        {0xff, 0, 0, 0, NULL, NULL,             /* terminating element */
            {0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
};

static int sdebug_add_host = DEF_NUM_HOST;
static int sdebug_ato = DEF_ATO;
static int sdebug_cdb_len = DEF_CDB_LEN;
static int sdebug_jdelay = DEF_JDELAY;  /* if > 0 then unit is jiffies */
static int sdebug_dev_size_mb = DEF_DEV_SIZE_MB;
static int sdebug_dif = DEF_DIF;
static int sdebug_dix = DEF_DIX;
static int sdebug_dsense = DEF_D_SENSE;
static int sdebug_every_nth = DEF_EVERY_NTH;
static int sdebug_fake_rw = DEF_FAKE_RW;
static unsigned int sdebug_guard = DEF_GUARD;
static int sdebug_lowest_aligned = DEF_LOWEST_ALIGNED;
static int sdebug_max_luns = DEF_MAX_LUNS;
static int sdebug_max_queue = SDEBUG_CANQUEUE;  /* per submit queue */
static unsigned int sdebug_medium_error_start = OPT_MEDIUM_ERR_ADDR;
static int sdebug_medium_error_count = OPT_MEDIUM_ERR_NUM;
static atomic_t retired_max_queue;      /* if > 0 then was prior max_queue */
static int sdebug_ndelay = DEF_NDELAY;  /* if > 0 then unit is nanoseconds */
static int sdebug_no_lun_0 = DEF_NO_LUN_0;
static int sdebug_no_uld;
static int sdebug_num_parts = DEF_NUM_PARTS;
static int sdebug_num_tgts = DEF_NUM_TGTS; /* targets per host */
static int sdebug_opt_blks = DEF_OPT_BLKS;
static int sdebug_opts = DEF_OPTS;
static int sdebug_physblk_exp = DEF_PHYSBLK_EXP;
static int sdebug_opt_xferlen_exp = DEF_OPT_XFERLEN_EXP;
static int sdebug_ptype = DEF_PTYPE; /* SCSI peripheral device type */
static int sdebug_scsi_level = DEF_SCSI_LEVEL;
static int sdebug_sector_size = DEF_SECTOR_SIZE;
static int sdebug_virtual_gb = DEF_VIRTUAL_GB;
static int sdebug_vpd_use_hostno = DEF_VPD_USE_HOSTNO;
static unsigned int sdebug_lbpu = DEF_LBPU;
static unsigned int sdebug_lbpws = DEF_LBPWS;
static unsigned int sdebug_lbpws10 = DEF_LBPWS10;
static unsigned int sdebug_lbprz = DEF_LBPRZ;
static unsigned int sdebug_unmap_alignment = DEF_UNMAP_ALIGNMENT;
static unsigned int sdebug_unmap_granularity = DEF_UNMAP_GRANULARITY;
static unsigned int sdebug_unmap_max_blocks = DEF_UNMAP_MAX_BLOCKS;
static unsigned int sdebug_unmap_max_desc = DEF_UNMAP_MAX_DESC;
static unsigned int sdebug_write_same_length = DEF_WRITESAME_LENGTH;
static int sdebug_uuid_ctl = DEF_UUID_CTL;
static bool sdebug_removable = DEF_REMOVABLE;
static bool sdebug_clustering;
static bool sdebug_host_lock = DEF_HOST_LOCK;
static bool sdebug_strict = DEF_STRICT;
static bool sdebug_any_injecting_opt;
static bool sdebug_verbose;
static bool have_dif_prot;
static bool write_since_sync;
static bool sdebug_statistics = DEF_STATISTICS;

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 */

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

static unsigned char *fake_storep;      /* ramdisk storage */
static struct t10_pi_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 int submit_queues = DEF_SUBMIT_QUEUES;  /* > 1 for multi-queue (mq) */
static struct sdebug_queue *sdebug_q_arr;  /* ptr to array of submit queues */

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;


/* Only do the extra work involved in logical block provisioning if one or
 * more of the lbpu, lbpws or lbpws10 parameters are given and we are doing
 * real reads and writes (i.e. not skipping them for speed).
 */
static inline bool scsi_debug_lbp(void)
{
        return 0 == sdebug_fake_rw &&
                (sdebug_lbpu || sdebug_lbpws || sdebug_lbpws10);
}

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

        return fake_storep + lba * sdebug_sector_size;
}

static struct t10_pi_tuple *dif_store(sector_t sector)
{
        sector = sector_div(sector, sdebug_store_sectors);

        return dif_storep + sector;
}

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) &&
                    (sdebug_num_tgts > hpnt->this_id))
                        hpnt->max_id = sdebug_num_tgts + 1;
                else
                        hpnt->max_id = sdebug_num_tgts;
                /* sdebug_max_luns; */
                hpnt->max_lun = SCSI_W_LUN_REPORT_LUNS + 1;
        }
        spin_unlock(&sdebug_host_list_lock);
}

enum sdeb_cmd_data {SDEB_IN_DATA = 0, SDEB_IN_CDB = 1};

/* Set in_bit to -1 to indicate no bit position of invalid field */
static void mk_sense_invalid_fld(struct scsi_cmnd *scp,
                                 enum sdeb_cmd_data c_d,
                                 int in_byte, int in_bit)
{
        unsigned char *sbuff;
        u8 sks[4];
        int sl, asc;

        sbuff = scp->sense_buffer;
        if (!sbuff) {
                sdev_printk(KERN_ERR, scp->device,
                            "%s: sense_buffer is NULL\n", __func__);
                return;
        }
        asc = c_d ? INVALID_FIELD_IN_CDB : INVALID_FIELD_IN_PARAM_LIST;
        memset(sbuff, 0, SCSI_SENSE_BUFFERSIZE);
        scsi_build_sense_buffer(sdebug_dsense, sbuff, ILLEGAL_REQUEST, asc, 0);
        memset(sks, 0, sizeof(sks));
        sks[0] = 0x80;
        if (c_d)
                sks[0] |= 0x40;
        if (in_bit >= 0) {
                sks[0] |= 0x8;
                sks[0] |= 0x7 & in_bit;
        }
        put_unaligned_be16(in_byte, sks + 1);
        if (sdebug_dsense) {
                sl = sbuff[7] + 8;
                sbuff[7] = sl;
                sbuff[sl] = 0x2;
                sbuff[sl + 1] = 0x6;
                memcpy(sbuff + sl + 4, sks, 3);
        } else
                memcpy(sbuff + 15, sks, 3);
        if (sdebug_verbose)
                sdev_printk(KERN_INFO, scp->device, "%s:  [sense_key,asc,ascq"
                            "]: [0x5,0x%x,0x0] %c byte=%d, bit=%d\n",
                            my_name, asc, c_d ? 'C' : 'D', in_byte, in_bit);
}

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(sdebug_dsense, sbuff, key, asc, asq);

        if (sdebug_verbose)
                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 mk_sense_invalid_opcode(struct scsi_cmnd *scp)
{
        mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_OPCODE, 0);
}

static int scsi_debug_ioctl(struct scsi_device *dev, int cmd, void __user *arg)
{
        if (sdebug_verbose) {
                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 void config_cdb_len(struct scsi_device *sdev)
{
        switch (sdebug_cdb_len) {
        case 6: /* suggest 6 byte READ, WRITE and MODE SENSE/SELECT */
                sdev->use_10_for_rw = false;
                sdev->use_16_for_rw = false;
                sdev->use_10_for_ms = false;
                break;
        case 10: /* suggest 10 byte RWs and 6 byte MODE SENSE/SELECT */
                sdev->use_10_for_rw = true;
                sdev->use_16_for_rw = false;
                sdev->use_10_for_ms = false;
                break;
        case 12: /* suggest 10 byte RWs and 10 byte MODE SENSE/SELECT */
                sdev->use_10_for_rw = true;
                sdev->use_16_for_rw = false;
                sdev->use_10_for_ms = true;
                break;
        case 16:
                sdev->use_10_for_rw = false;
                sdev->use_16_for_rw = true;
                sdev->use_10_for_ms = true;
                break;
        case 32: /* No knobs to suggest this so same as 16 for now */
                sdev->use_10_for_rw = false;
                sdev->use_16_for_rw = true;
                sdev->use_10_for_ms = true;
                break;
        default:
                pr_warn("unexpected cdb_len=%d, force to 10\n",
                        sdebug_cdb_len);
                sdev->use_10_for_rw = true;
                sdev->use_16_for_rw = false;
                sdev->use_10_for_ms = false;
                sdebug_cdb_len = 10;
                break;
        }
}

static void all_config_cdb_len(void)
{
        struct sdebug_host_info *sdbg_host;
        struct Scsi_Host *shost;
        struct scsi_device *sdev;

        spin_lock(&sdebug_host_list_lock);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                shost = sdbg_host->shost;
                shost_for_each_device(sdev, shost) {
                        config_cdb_len(sdev);
                }
        }
        spin_unlock(&sdebug_host_list_lock);
}

static void clear_luns_changed_on_target(struct sdebug_dev_info *devip)
{
        struct sdebug_host_info *sdhp;
        struct sdebug_dev_info *dp;

        spin_lock(&sdebug_host_list_lock);
        list_for_each_entry(sdhp, &sdebug_host_list, host_list) {
                list_for_each_entry(dp, &sdhp->dev_info_list, dev_list) {
                        if ((devip->sdbg_host == dp->sdbg_host) &&
                            (devip->target == dp->target))
                                clear_bit(SDEBUG_UA_LUNS_CHANGED, dp->uas_bm);
                }
        }
        spin_unlock(&sdebug_host_list_lock);
}

static int make_ua(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
{
        int k;

        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(scp, UNIT_ATTENTION, UA_RESET_ASC,
                                        POWER_ON_RESET_ASCQ);
                        if (sdebug_verbose)
                                cp = "power on reset";
                        break;
                case SDEBUG_UA_BUS_RESET:
                        mk_sense_buffer(scp, UNIT_ATTENTION, UA_RESET_ASC,
                                        BUS_RESET_ASCQ);
                        if (sdebug_verbose)
                                cp = "bus reset";
                        break;
                case SDEBUG_UA_MODE_CHANGED:
                        mk_sense_buffer(scp, UNIT_ATTENTION, UA_CHANGED_ASC,
                                        MODE_CHANGED_ASCQ);
                        if (sdebug_verbose)
                                cp = "mode parameters changed";
                        break;
                case SDEBUG_UA_CAPACITY_CHANGED:
                        mk_sense_buffer(scp, UNIT_ATTENTION, UA_CHANGED_ASC,
                                        CAPACITY_CHANGED_ASCQ);
                        if (sdebug_verbose)
                                cp = "capacity data changed";
                        break;
                case SDEBUG_UA_MICROCODE_CHANGED:
                        mk_sense_buffer(scp, UNIT_ATTENTION,
                                        TARGET_CHANGED_ASC,
                                        MICROCODE_CHANGED_ASCQ);
                        if (sdebug_verbose)
                                cp = "microcode has been changed";
                        break;
                case SDEBUG_UA_MICROCODE_CHANGED_WO_RESET:
                        mk_sense_buffer(scp, UNIT_ATTENTION,
                                        TARGET_CHANGED_ASC,
                                        MICROCODE_CHANGED_WO_RESET_ASCQ);
                        if (sdebug_verbose)
                                cp = "microcode has been changed without reset";
                        break;
                case SDEBUG_UA_LUNS_CHANGED:
                        /*
                         * SPC-3 behavior is to report a UNIT ATTENTION with
                         * ASC/ASCQ REPORTED LUNS DATA HAS CHANGED on every LUN
                         * on the target, until a REPORT LUNS command is
                         * received.  SPC-4 behavior is to report it only once.
                         * NOTE:  sdebug_scsi_level does not use the same
                         * values as struct scsi_device->scsi_level.
                         */
                        if (sdebug_scsi_level >= 6)     /* SPC-4 and above */
                                clear_luns_changed_on_target(devip);
                        mk_sense_buffer(scp, UNIT_ATTENTION,
                                        TARGET_CHANGED_ASC,
                                        LUNS_CHANGED_ASCQ);
                        if (sdebug_verbose)
                                cp = "reported luns data has changed";
                        break;
                default:
                        pr_warn("unexpected unit attention code=%d\n", k);
                        if (sdebug_verbose)
                                cp = "unknown";
                        break;
                }
                clear_bit(k, devip->uas_bm);
                if (sdebug_verbose)
                        sdev_printk(KERN_INFO, scp->device,

                                   "%s reports: Unit attention: %s\n",
                                   my_name, cp);
                return check_condition_result;
        }
        return 0;
}

/* Build SCSI "data-in" buffer. Returns 0 if ok else (DID_ERROR << 16). */
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;
}

/* Partial build of SCSI "data-in" buffer. Returns 0 if ok else
 * (DID_ERROR << 16). Can write to offset in data-in buffer. If multiple
 * calls, not required to write in ascending offset order. Assumes resid
 * set to scsi_bufflen() prior to any calls.
 */
static int p_fill_from_dev_buffer(struct scsi_cmnd *scp, const void *arr,
                                  int arr_len, unsigned int off_dst)
{
        int act_len, n;
        struct scsi_data_buffer *sdb = scsi_in(scp);
        off_t skip = off_dst;

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

        act_len = sg_pcopy_from_buffer(sdb->table.sgl, sdb->table.nents,
                                       arr, arr_len, skip);
        pr_debug("%s: off_dst=%u, scsi_bufflen=%u, act_len=%u, resid=%d\n",
                 __func__, off_dst, scsi_bufflen(scp), act_len, sdb->resid);
        n = (int)scsi_bufflen(scp) - ((int)off_dst + act_len);
        sdb->resid = min(sdb->resid, n);
        return 0;
}

/* Fetches from SCSI "data-out" buffer. 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 char sdebug_inq_vendor_id[9] = "Linux   ";
static char sdebug_inq_product_id[17] = "scsi_debug      ";
static char sdebug_inq_product_rev[5] = SDEBUG_VERSION;
/* Use some locally assigned NAAs for SAS addresses. */
static const u64 naa3_comp_a = 0x3222222000000000ULL;
static const u64 naa3_comp_b = 0x3333333000000000ULL;
static const u64 naa3_comp_c = 0x3111111000000000ULL;

/* Device identification VPD page. Returns number of bytes placed in arr */
static int inquiry_vpd_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,
                          const uuid_t *lu_name)
{
        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], sdebug_inq_vendor_id, 8);
        memcpy(&arr[12], sdebug_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) {
                if (sdebug_uuid_ctl) {
                        /* Locally assigned UUID */
                        arr[num++] = 0x1;  /* binary (not necessarily sas) */
                        arr[num++] = 0xa;  /* PIV=0, lu, naa */
                        arr[num++] = 0x0;
                        arr[num++] = 0x12;
                        arr[num++] = 0x10; /* uuid type=1, locally assigned */
                        arr[num++] = 0x0;
                        memcpy(arr + num, lu_name, 16);
                        num += 16;
                } else {
                        /* NAA-3, Logical unit identifier (binary) */
                        arr[num++] = 0x1;  /* binary (not necessarily sas) */
                        arr[num++] = 0x3;  /* PIV=0, lu, naa */
                        arr[num++] = 0x0;
                        arr[num++] = 0x8;
                        put_unaligned_be64(naa3_comp_b + dev_id_num, arr + num);
                        num += 8;
                }
                /* 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-3, Target port identifier */
        arr[num++] = 0x61;      /* proto=sas, binary */
        arr[num++] = 0x93;      /* piv=1, target port, naa */
        arr[num++] = 0x0;
        arr[num++] = 0x8;
        put_unaligned_be64(naa3_comp_a + port_a, arr + num);
        num += 8;
        /* NAA-3, 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;
        put_unaligned_be16(port_group_id, arr + num);
        num += 2;
        /* NAA-3, Target device identifier */
        arr[num++] = 0x61;      /* proto=sas, binary */
        arr[num++] = 0xa3;      /* piv=1, target device, naa */
        arr[num++] = 0x0;
        arr[num++] = 0x8;
        put_unaligned_be64(naa3_comp_a + target_dev_id, arr + num);
        num += 8;
        /* 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.32222220", 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_vpd_84(unsigned char *arr)
{
        memcpy(arr, vpd84_data, sizeof(vpd84_data));
        return sizeof(vpd84_data);
}

/* Management network addresses VPD page */
static int inquiry_vpd_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_vpd_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 */
        put_unaligned_be64(naa3_comp_a + port_a, arr + num);
        num += 8;
        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 */
        put_unaligned_be64(naa3_comp_a + port_b, arr + num);
        num += 8;

        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_vpd_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_vpd_b0(unsigned char *arr)
{
        unsigned int gran;

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

        /* Optimal transfer length granularity */
        if (sdebug_opt_xferlen_exp != 0 &&
            sdebug_physblk_exp < sdebug_opt_xferlen_exp)
                gran = 1 << sdebug_opt_xferlen_exp;
        else
                gran = 1 << sdebug_physblk_exp;
        put_unaligned_be16(gran, arr + 2);

        /* Maximum Transfer Length */
        if (sdebug_store_sectors > 0x400)
                put_unaligned_be32(sdebug_store_sectors, arr + 4);

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

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

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

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

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

        /* Maximum WRITE SAME Length */
        put_unaligned_be64(sdebug_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_vpd_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-4) */
static int inquiry_vpd_b2(unsigned char *arr)
{
        memset(arr, 0, 0x4);
        arr[0] = 0;                     /* threshold exponent */
        if (sdebug_lbpu)
                arr[1] = 1 << 7;
        if (sdebug_lbpws)
                arr[1] |= 1 << 6;
        if (sdebug_lbpws10)
                arr[1] |= 1 << 5;
        if (sdebug_lbprz && scsi_debug_lbp())
                arr[1] |= (sdebug_lbprz & 0x7) << 2;  /* sbc4r07 and later */
        /* anc_sup=0; dp=0 (no provisioning group descriptor) */
        /* minimum_percentage=0; provisioning_type=0 (unknown) */
        /* threshold_percentage=0 */
        return 0x4;
}

#define SDEBUG_LONG_INQ_SZ 96
#define SDEBUG_MAX_INQ_ARR_SZ 584

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

        alloc_len = get_unaligned_be16(cmd + 3);
        arr = kzalloc(SDEBUG_MAX_INQ_ARR_SZ, GFP_ATOMIC);
        if (! arr)
                return DID_REQUEUE << 16;
        is_disk = (sdebug_ptype == TYPE_DISK);
        have_wlun = scsi_is_wlun(scp->device->lun);
        if (have_wlun)
                pq_pdt = TYPE_WLUN;     /* present, wlun */
        else if (sdebug_no_lun_0 && (devip->lun == SDEBUG_LUN_0_VAL))
                pq_pdt = 0x7f;  /* not present, PQ=3, PDT=0x1f */
        else
                pq_pdt = (sdebug_ptype & 0x1f);
        arr[0] = pq_pdt;
        if (0x2 & cmd[1]) {  /* CMDDT bit set */
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 1, 1);
                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 (sdebug_vpd_use_hostno == 0)
                        host_no = 0;
                lu_id_num = have_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 */
                        if (is_disk) {    /* SBC only */
                                arr[n++] = 0x89;  /* ATA information */
                                arr[n++] = 0xb0;  /* Block limits */
                                arr[n++] = 0xb1;  /* Block characteristics */
                                arr[n++] = 0xb2;  /* Logical Block Prov */
                        }
                        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_vpd_83(&arr[4], port_group_id,
                                                target_dev_id, lu_id_num,
                                                lu_id_str, len,
                                                &devip->lu_name);
                } else if (0x84 == cmd[2]) { /* Software interface ident. */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_vpd_84(&arr[4]);
                } else if (0x85 == cmd[2]) { /* Management network addresses */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_vpd_85(&arr[4]);
                } else if (0x86 == cmd[2]) { /* extended inquiry */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = 0x3c;  /* number of following entries */
                        if (sdebug_dif == T10_PI_TYPE3_PROTECTION)
                                arr[4] = 0x4;   /* SPT: GRD_CHK:1 */
                        else if (have_dif_prot)
                                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_vpd_88(&arr[4], target_dev_id);
                } else if (is_disk && 0x89 == cmd[2]) { /* ATA information */
                        arr[1] = cmd[2];        /*sanity */
                        n = inquiry_vpd_89(&arr[4]);
                        put_unaligned_be16(n, arr + 2);
                } else if (is_disk && 0xb0 == cmd[2]) { /* Block limits */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_vpd_b0(&arr[4]);
                } else if (is_disk && 0xb1 == cmd[2]) { /* Block char. */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_vpd_b1(&arr[4]);
                } else if (is_disk && 0xb2 == cmd[2]) { /* LB Prov. */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_vpd_b2(&arr[4]);
                } else {
                        mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, -1);
                        kfree(arr);
                        return check_condition_result;
                }
                len = min(get_unaligned_be16(arr + 2) + 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] = sdebug_removable ? 0x80 : 0;   /* Removable disk */
        arr[2] = sdebug_scsi_level;
        arr[3] = 2;    /* response_data_format==2 */
        arr[4] = SDEBUG_LONG_INQ_SZ - 5;
        arr[5] = (int)have_dif_prot;    /* PROTECT bit */
        if (sdebug_vpd_use_hostno == 0)
                arr[5] |= 0x10; /* claim: implicit TPGS */
        arr[6] = 0x10; /* claim: MultiP */
        /* arr[6] |= 0x40; ... claim: EncServ (enclosure services) */
        arr[7] = 0xa; /* claim: LINKED + CMDQUE */
        memcpy(&arr[8], sdebug_inq_vendor_id, 8);
        memcpy(&arr[16], sdebug_inq_product_id, 16);
        memcpy(&arr[32], sdebug_inq_product_rev, 4);
        /* Use Vendor Specific area to place driver date in ASCII hex */
        memcpy(&arr[36], sdebug_version_date, 8);
        /* version descriptors (2 bytes each) follow */
        put_unaligned_be16(0xc0, arr + 58);   /* SAM-6 no version claimed */
        put_unaligned_be16(0x5c0, arr + 60);  /* SPC-5 no version claimed */
        n = 62;
        if (is_disk) {          /* SBC-4 no version claimed */
                put_unaligned_be16(0x600, arr + n);
                n += 2;
        } else if (sdebug_ptype == TYPE_TAPE) { /* SSC-4 rev 3 */
                put_unaligned_be16(0x525, arr + n);
                n += 2;
        }
        put_unaligned_be16(0x2100, arr + n);    /* SPL-4 no version claimed */
        ret = fill_from_dev_buffer(scp, arr,
                            min(alloc_len, SDEBUG_LONG_INQ_SZ));
        kfree(arr);
        return ret;
}

static unsigned char iec_m_pg[] = {0x1c, 0xa, 0x08, 0, 0, 0, 0, 0,
                                   0, 0, 0x0, 0x0};

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];
        bool dsense;
        int len = 18;

        memset(arr, 0, sizeof(arr));
        dsense = !!(cmd[1] & 1);
        sbuff = scp->sense_buffer;
        if ((iec_m_pg[2] & 0x4) && (6 == (iec_m_pg[3] & 0xf))) {
                if (dsense) {
                        arr[0] = 0x72;
                        arr[1] = 0x0;           /* NO_SENSE in sense_key */
                        arr[2] = THRESHOLD_EXCEEDED;
                        arr[3] = 0xff;          /* TEST set and MRIE==6 */
                        len = 8;
                } 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 (arr[0] >= 0x70 && dsense == sdebug_dsense)
                        ;       /* have sense and formats match */
                else if (arr[0] <= 0x70) {
                        if (dsense) {
                                memset(arr, 0, 8);
                                arr[0] = 0x72;
                                len = 8;
                        } else {
                                memset(arr, 0, 18);
                                arr[0] = 0x70;
                                arr[7] = 0xa;
                        }
                } else if (dsense) {
                        memset(arr, 0, 8);
                        arr[0] = 0x72;
                        arr[1] = sbuff[2];     /* sense key */
                        arr[2] = sbuff[12];    /* asc */
                        arr[3] = sbuff[13];    /* ascq */
                        len = 8;
                } else {
                        memset(arr, 0, 18);
                        arr[0] = 0x70;
                        arr[2] = sbuff[1];
                        arr[7] = 0xa;
                        arr[12] = sbuff[1];
                        arr[13] = sbuff[3];
                }

        }
        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, stop;
        bool changing;

        power_cond = (cmd[4] & 0xf0) >> 4;
        if (power_cond) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 4, 7);
                return check_condition_result;
        }
        stop = !(cmd[4] & 1);
        changing = atomic_read(&devip->stopped) == !stop;
        atomic_xchg(&devip->stopped, stop);
        if (!changing || cmd[1] & 0x1)  /* state unchanged or IMMED set */
                return SDEG_RES_IMMED_MASK;
        else
                return 0;
}

static sector_t get_sdebug_capacity(void)
{
        static const unsigned int gibibyte = 1073741824;

        if (sdebug_virtual_gb > 0)
                return (sector_t)sdebug_virtual_gb *
                        (gibibyte / sdebug_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;

        /* 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;
                put_unaligned_be32(capac, arr + 0);
        } else
                put_unaligned_be32(0xffffffff, arr + 0);
        put_unaligned_be16(sdebug_sector_size, arr + 6);
        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];
        int alloc_len;

        alloc_len = get_unaligned_be32(cmd + 10);
        /* following just in case virtual_gb changed */
        sdebug_capacity = get_sdebug_capacity();
        memset(arr, 0, SDEBUG_READCAP16_ARR_SZ);
        put_unaligned_be64((u64)(sdebug_capacity - 1), arr + 0);
        put_unaligned_be32(sdebug_sector_size, arr + 8);
        arr[13] = sdebug_physblk_exp & 0xf;
        arr[14] = (sdebug_lowest_aligned >> 8) & 0x3f;

        if (scsi_debug_lbp()) {
                arr[14] |= 0x80; /* LBPME */
                /* from sbc4r07, this LBPRZ field is 1 bit, but the LBPRZ in
                 * the LB Provisioning VPD page is 3 bits. Note that lbprz=2
                 * in the wider field maps to 0 in this field.
                 */
                if (sdebug_lbprz & 1)   /* precisely what the draft requires */
                        arr[14] |= 0x40;
        }

        arr[15] = sdebug_lowest_aligned & 0xff;

        if (have_dif_prot) {
                arr[12] = (sdebug_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 = get_unaligned_be32(cmd + 6);
        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 (sdebug_vpd_use_hostno == 0) {
                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; /* only support active/optimized paths */
        }
        put_unaligned_be16(port_group_a, arr + n);
        n += 2;
        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 */
        put_unaligned_be16(port_a, arr + n);
        n += 2;
        arr[n++] = 3;    /* Port unavailable */
        arr[n++] = 0x08; /* claim: only unavailalbe paths are supported */
        put_unaligned_be16(port_group_b, arr + n);
        n += 2;
        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 */
        put_unaligned_be16(port_b, arr + n);
        n += 2;

        rlen = n - 4;
        put_unaligned_be32(rlen, arr + 0);

        /*
         * 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;
}

static int resp_rsup_opcodes(struct scsi_cmnd *scp,
                             struct sdebug_dev_info *devip)
{
        bool rctd;
        u8 reporting_opts, req_opcode, sdeb_i, supp;
        u16 req_sa, u;
        u32 alloc_len, a_len;
        int k, offset, len, errsts, count, bump, na;
        const struct opcode_info_t *oip;
        const struct opcode_info_t *r_oip;
        u8 *arr;
        u8 *cmd = scp->cmnd;

        rctd = !!(cmd[2] & 0x80);
        reporting_opts = cmd[2] & 0x7;
        req_opcode = cmd[3];
        req_sa = get_unaligned_be16(cmd + 4);
        alloc_len = get_unaligned_be32(cmd + 6);
        if (alloc_len < 4 || alloc_len > 0xffff) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 6, -1);
                return check_condition_result;
        }
        if (alloc_len > 8192)
                a_len = 8192;
        else
                a_len = alloc_len;
        arr = kzalloc((a_len < 256) ? 320 : a_len + 64, GFP_ATOMIC);
        if (NULL == arr) {
                mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC,
                                INSUFF_RES_ASCQ);
                return check_condition_result;
        }
        switch (reporting_opts) {
        case 0: /* all commands */
                /* count number of commands */
                for (count = 0, oip = opcode_info_arr;
                     oip->num_attached != 0xff; ++oip) {
                        if (F_INV_OP & oip->flags)
                                continue;
                        count += (oip->num_attached + 1);
                }
                bump = rctd ? 20 : 8;
                put_unaligned_be32(count * bump, arr);
                for (offset = 4, oip = opcode_info_arr;
                     oip->num_attached != 0xff && offset < a_len; ++oip) {
                        if (F_INV_OP & oip->flags)
                                continue;
                        na = oip->num_attached;
                        arr[offset] = oip->opcode;
                        put_unaligned_be16(oip->sa, arr + offset + 2);
                        if (rctd)
                                arr[offset + 5] |= 0x2;
                        if (FF_SA & oip->flags)
                                arr[offset + 5] |= 0x1;
                        put_unaligned_be16(oip->len_mask[0], arr + offset + 6);
                        if (rctd)
                                put_unaligned_be16(0xa, arr + offset + 8);
                        r_oip = oip;
                        for (k = 0, oip = oip->arrp; k < na; ++k, ++oip) {
                                if (F_INV_OP & oip->flags)
                                        continue;
                                offset += bump;
                                arr[offset] = oip->opcode;
                                put_unaligned_be16(oip->sa, arr + offset + 2);
                                if (rctd)
                                        arr[offset + 5] |= 0x2;
                                if (FF_SA & oip->flags)
                                        arr[offset + 5] |= 0x1;
                                put_unaligned_be16(oip->len_mask[0],
                                                   arr + offset + 6);
                                if (rctd)
                                        put_unaligned_be16(0xa,
                                                           arr + offset + 8);
                        }
                        oip = r_oip;
                        offset += bump;
                }
                break;
        case 1: /* one command: opcode only */
        case 2: /* one command: opcode plus service action */
        case 3: /* one command: if sa==0 then opcode only else opcode+sa */
                sdeb_i = opcode_ind_arr[req_opcode];
                oip = &opcode_info_arr[sdeb_i];
                if (F_INV_OP & oip->flags) {
                        supp = 1;
                        offset = 4;
                } else {
                        if (1 == reporting_opts) {
                                if (FF_SA & oip->flags) {
                                        mk_sense_invalid_fld(scp, SDEB_IN_CDB,
                                                             2, 2);
                                        kfree(arr);
                                        return check_condition_result;
                                }
                                req_sa = 0;
                        } else if (2 == reporting_opts &&
                                   0 == (FF_SA & oip->flags)) {
                                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 4, -1);
                                kfree(arr);     /* point at requested sa */
                                return check_condition_result;
                        }
                        if (0 == (FF_SA & oip->flags) &&
                            req_opcode == oip->opcode)
                                supp = 3;
                        else if (0 == (FF_SA & oip->flags)) {
                                na = oip->num_attached;
                                for (k = 0, oip = oip->arrp; k < na;
                                     ++k, ++oip) {
                                        if (req_opcode == oip->opcode)
                                                break;
                                }
                                supp = (k >= na) ? 1 : 3;
                        } else if (req_sa != oip->sa) {
                                na = oip->num_attached;
                                for (k = 0, oip = oip->arrp; k < na;
                                     ++k, ++oip) {
                                        if (req_sa == oip->sa)
                                                break;
                                }
                                supp = (k >= na) ? 1 : 3;
                        } else
                                supp = 3;
                        if (3 == supp) {
                                u = oip->len_mask[0];
                                put_unaligned_be16(u, arr + 2);
                                arr[4] = oip->opcode;
                                for (k = 1; k < u; ++k)
                                        arr[4 + k] = (k < 16) ?
                                                 oip->len_mask[k] : 0xff;
                                offset = 4 + u;
                        } else
                                offset = 4;
                }
                arr[1] = (rctd ? 0x80 : 0) | supp;
                if (rctd) {
                        put_unaligned_be16(0xa, arr + offset);
                        offset += 12;
                }
                break;
        default:
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, 2);
                kfree(arr);
                return check_condition_result;
        }
        offset = (offset < a_len) ? offset : a_len;
        len = (offset < alloc_len) ? offset : alloc_len;
        errsts = fill_from_dev_buffer(scp, arr, len);
        kfree(arr);
        return errsts;
}

static int resp_rsup_tmfs(struct scsi_cmnd *scp,
                          struct sdebug_dev_info *devip)
{
        bool repd;
        u32 alloc_len, len;
        u8 arr[16];
        u8 *cmd = scp->cmnd;

        memset(arr, 0, sizeof(arr));
        repd = !!(cmd[2] & 0x80);
        alloc_len = get_unaligned_be32(cmd + 6);
        if (alloc_len < 4) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 6, -1);
                return check_condition_result;
        }
        arr[0] = 0xc8;          /* ATS | ATSS | LURS */
        arr[1] = 0x1;           /* ITNRS */
        if (repd) {
                arr[3] = 0xc;
                len = 16;
        } else
                len = 4;

        len = (len < alloc_len) ? len : alloc_len;
        return fill_from_dev_buffer(scp, arr, len);
}

/* <<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));
        put_unaligned_be16(sdebug_sectors_per, p + 10);
        put_unaligned_be16(sdebug_sector_size, p + 12);
        if (sdebug_removable)
                p[20] |= 0x20; /* should agree with INQUIRY */
        if (1 == pcontrol)
                memset(p + 2, 0, sizeof(format_pg) - 2);
        return sizeof(format_pg);
}

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 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 (SDEBUG_OPT_N_WCE & sdebug_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 unsigned char ctrl_m_pg[] = {0xa, 10, 2, 0, 0, 0, 0, 0,
                                    0, 0, 0x2, 0x4b};

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

        if (sdebug_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,
                    0, 0, 0, 0, 0, 0, 0, 0,     /* insert SAS addr */
                    0, 0, 0, 0, 0, 0, 0, 0,     /* insert SAS addr */
                    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,
                    0, 0, 0, 0, 0, 0, 0, 0,     /* insert SAS addr */
                    0, 0, 0, 0, 0, 0, 0, 0,     /* insert SAS addr */
                    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;

        put_unaligned_be64(naa3_comp_a, sas_pcd_m_pg + 16);
        put_unaligned_be64(naa3_comp_c + 1, sas_pcd_m_pg + 24);
        put_unaligned_be64(naa3_comp_a, sas_pcd_m_pg + 64);
        put_unaligned_be64(naa3_comp_c + 1, sas_pcd_m_pg + 72);
        port_a = target_dev_id + 1;
        port_b = port_a + 1;
        memcpy(p, sas_pcd_m_pg, sizeof(sas_pcd_m_pg));
        put_unaligned_be32(port_a, p + 20);
        put_unaligned_be32(port_b, p + 48 + 20);
        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,
                           struct sdebug_dev_info *devip)
{
        int pcontrol, pcode, subpcode, bd_len;
        unsigned char dev_spec;
        int alloc_len, offset, len, target_dev_id;
        int target = scp->device->id;
        unsigned char *ap;
        unsigned char arr[SDEBUG_MAX_MSENSE_SZ];
        unsigned char *cmd = scp->cmnd;
        bool dbd, llbaa, msense_6, is_disk, bad_pcode;

        dbd = !!(cmd[1] & 0x8);         /* disable block descriptors */
        pcontrol = (cmd[2] & 0xc0) >> 6;
        pcode = cmd[2] & 0x3f;
        subpcode = cmd[3];
        msense_6 = (MODE_SENSE == cmd[0]);
        llbaa = msense_6 ? false : !!(cmd[1] & 0x10);
        is_disk = (sdebug_ptype == TYPE_DISK);
        if (is_disk && !dbd)
                bd_len = llbaa ? 16 : 8;
        else
                bd_len = 0;
        alloc_len = msense_6 ? cmd[4] : get_unaligned_be16(cmd + 7);
        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;
        /* for disks set DPOFUA bit and clear write protect (WP) bit */
        if (is_disk)
                dev_spec = 0x10;        /* =0x90 if WP=1 implies read-only */
        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)
                        put_unaligned_be32(0xffffffff, ap + 0);
                else
                        put_unaligned_be32(sdebug_capacity, ap + 0);
                put_unaligned_be16(sdebug_sector_size, ap + 6);
                offset += bd_len;
                ap = arr + offset;
        } else if (16 == bd_len) {
                put_unaligned_be64((u64)sdebug_capacity, ap + 0);
                put_unaligned_be32(sdebug_sector_size, ap + 12);
                offset += bd_len;
                ap = arr + offset;
        }

        if ((subpcode > 0x0) && (subpcode < 0xff) && (0x19 != pcode)) {
                /* TODO: Control Extension page */
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
                return check_condition_result;
        }
        bad_pcode = false;

        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 */
                if (is_disk) {
                        len = resp_format_pg(ap, pcontrol, target);
                        offset += len;
                } else
                        bad_pcode = true;
                break;
        case 0x8:       /* Caching page, direct access */
                if (is_disk) {
                        len = resp_caching_pg(ap, pcontrol, target);
                        offset += len;
                } else
                        bad_pcode = true;
                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_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
                        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);
                        if (is_disk) {
                                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);
                        offset += len;
                } else {
                        mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
                        return check_condition_result;
                }
                break;
        default:
                bad_pcode = true;
                break;
        }
        if (bad_pcode) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, 5);
                return check_condition_result;
        }
        if (msense_6)
                arr[0] = offset - 1;
        else
                put_unaligned_be16((offset - 2), arr + 0);
        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,
                            struct sdebug_dev_info *devip)
{
        int pf, sp, ps, md_len, bd_len, off, spf, pg_len;
        int param_len, res, mpage;
        unsigned char arr[SDEBUG_MAX_MSELECT_SZ];
        unsigned char *cmd = scp->cmnd;
        int mselect6 = (MODE_SELECT == cmd[0]);

        memset(arr, 0, sizeof(arr));
        pf = cmd[1] & 0x10;
        sp = cmd[1] & 0x1;
        param_len = mselect6 ? cmd[4] : get_unaligned_be16(cmd + 7);
        if ((0 == pf) || sp || (param_len > SDEBUG_MAX_MSELECT_SZ)) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, mselect6 ? 4 : 7, -1);
                return check_condition_result;
        }
        res = fetch_to_dev_buffer(scp, arr, param_len);
        if (-1 == res)
                return DID_ERROR << 16;
        else if (sdebug_verbose && (res < param_len))
                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) : (get_unaligned_be16(arr + 0) + 2);
        bd_len = mselect6 ? arr[3] : get_unaligned_be16(arr + 6);
        if (md_len > 2) {
                mk_sense_invalid_fld(scp, SDEB_IN_DATA, 0, -1);
                return check_condition_result;
        }
        off = bd_len + (mselect6 ? 4 : 8);
        mpage = arr[off] & 0x3f;
        ps = !!(arr[off] & 0x80);
        if (ps) {
                mk_sense_invalid_fld(scp, SDEB_IN_DATA, off, 7);
                return check_condition_result;
        }
        spf = !!(arr[off] & 0x40);
        pg_len = spf ? (get_unaligned_be16(arr + off + 2) + 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);
                        sdebug_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_invalid_fld(scp, SDEB_IN_DATA, off, 5);
        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, pcode, subpcode, alloc_len, len, n;
        unsigned char arr[SDEBUG_MAX_LSENSE_SZ];
        unsigned char *cmd = scp->cmnd;

        memset(arr, 0, sizeof(arr));
        ppc = cmd[1] & 0x2;
        sp = cmd[1] & 0x1;
        if (ppc || sp) {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 1, ppc ? 1 : 0);
                return check_condition_result;
        }
        pcode = cmd[2] & 0x3f;
        subpcode = cmd[3] & 0xff;
        alloc_len = get_unaligned_be16(cmd + 7);
        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_invalid_fld(scp, SDEB_IN_CDB, 2, 5);
                        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_invalid_fld(scp, SDEB_IN_CDB, 2, 5);
                        return check_condition_result;
                }
        } else {
                mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
                return check_condition_result;
        }
        len = min(get_unaligned_be16(arr + 2) + 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, LBA_OUT_OF_RANGE, 0);
                return check_condition_result;
        }
        /* transfer length excessive (tie in to block limits VPD page) */
        if (num > sdebug_store_sectors) {
                /* needs work to find which cdb byte 'num' comes from */
                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, u32 sg_skip, u64 lba,
                            u32 num, bool do_write)
{
        int ret;
        u64 block, rest = 0;
        struct scsi_data_buffer *sdb;
        enum dma_data_direction dir;

        if (do_write) {
                sdb = scsi_out(scmd);
                dir = DMA_TO_DEVICE;
                write_since_sync = true;
        } else {
                sdb = scsi_in(scmd);
                dir = DMA_FROM_DEVICE;
        }

        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 = sg_copy_buffer(sdb->table.sgl, sdb->table.nents,
                   fake_storep + (block * sdebug_sector_size),
                   (num - rest) * sdebug_sector_size, sg_skip, do_write);
        if (ret != (num - rest) * sdebug_sector_size)
                return ret;

        if (rest) {
                ret += sg_copy_buffer(sdb->table.sgl, sdb->table.nents,
                            fake_storep, rest * sdebug_sector_size,
                            sg_skip + ((num - rest) * sdebug_sector_size),
                            do_write);
        }

        return ret;
}

/* If fake_store(lba,num) compares equal to arr(num), then copy top half of
 * arr into fake_store(lba,num) and return true. If comparison fails then
 * return false. */
static bool comp_write_worker(u64 lba, u32 num, const u8 *arr)
{
        bool res;
        u64 block, rest = 0;
        u32 store_blks = sdebug_store_sectors;
        u32 lb_size = sdebug_sector_size;

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

        res = !memcmp(fake_storep + (block * lb_size), arr,
                      (num - rest) * lb_size);
        if (!res)
                return res;
        if (rest)
                res = memcmp(fake_storep, arr + ((num - rest) * lb_size),
                             rest * lb_size);
        if (!res)
                return res;
        arr += num * lb_size;
        memcpy(fake_storep + (block * lb_size), arr, (num - rest) * lb_size);
        if (rest)
                memcpy(fake_storep, arr + ((num - rest) * lb_size),
                       rest * lb_size);
        return res;
}

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

        if (sdebug_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 t10_pi_tuple *sdt, const void *data,
                      sector_t sector, u32 ei_lba)
{
        __be16 csum = dif_compute_csum(data, sdebug_sector_size);

        if (sdt->guard_tag != csum) {
                pr_err("GUARD check failed on sector %lu rcvd 0x%04x, data 0x%04x\n",
                        (unsigned long)sector,
                        be16_to_cpu(sdt->guard_tag),
                        be16_to_cpu(csum));
                return 0x01;
        }
        if (sdebug_dif == T10_PI_TYPE1_PROTECTION &&
            be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
                pr_err("REF check failed on sector %lu\n",
                        (unsigned long)sector);
                return 0x03;
        }
        if (sdebug_dif == T10_PI_TYPE2_PROTECTION &&
            be32_to_cpu(sdt->ref_tag) != ei_lba) {
                pr_err("REF check failed on sector %lu\n",
                        (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 t10_pi_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_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
{
        u8 *cmd = scp->cmnd;
        struct sdebug_queued_cmd *sqcp;
        u64 lba;
        u32 num;
        u32 ei_lba;
        unsigned long iflags;
        int ret;
        bool check_prot;

        switch (cmd[0]) {
        case READ_16:
                ei_lba = 0;
                lba = get_unaligned_be64(cmd + 2);
                num = get_unaligned_be32(cmd + 10);
                check_prot = true;
                break;
        case READ_10:
                ei_lba = 0;
                lba = get_unaligned_be32(cmd + 2);
                num = get_unaligned_be16(cmd + 7);
                check_prot = true;
                break;
        case READ_6:
                ei_lba = 0;
                lba = (u32)cmd[3] | (u32)cmd[2] << 8 |
                      (u32)(cmd[1] & 0x1f) << 16;
                num = (0 == cmd[4]) ? 256 : cmd[4];
                check_prot = true;
                break;
        case READ_12:
                ei_lba = 0;
                lba = get_unaligned_be32(cmd + 2);
                num = get_unaligned_be32(cmd + 6);
                check_prot = true;
                break;
        case XDWRITEREAD_10:
                ei_lba = 0;
                lba = get_unaligned_be32(cmd + 2);
                num = get_unaligned_be16(cmd + 7);
                check_prot = false;
                break;
        default:        /* assume READ(32) */
                lba = get_unaligned_be64(cmd + 12);
                ei_lba = get_unaligned_be32(cmd + 20);
                num = get_unaligned_be32(cmd + 28);
                check_prot = false;
                break;
        }
        if (unlikely(have_dif_prot && check_prot)) {
                if (sdebug_dif == T10_PI_TYPE2_PROTECTION &&
                    (cmd[1] & 0xe0)) {
                        mk_sense_invalid_opcode(scp);
                        return check_condition_result;
                }
                if ((sdebug_dif == T10_PI_TYPE1_PROTECTION ||
                     sdebug_dif == T10_PI_TYPE3_PROTECTION) &&
                    (cmd[1] & 0xe0) == 0)
                        sdev_printk(KERN_ERR, scp->device, "Unprotected RD "
                                    "to DIF device\n");
        }
        if (unlikely(sdebug_any_injecting_opt)) {
                sqcp = (struct sdebug_queued_cmd *)scp->host_scribble;

                if (sqcp) {
                        if (sqcp->inj_short)
                                num /= 2;
                }
        } else
                sqcp = NULL;

        /* inline check_device_access_params() */
        if (unlikely(lba + num > sdebug_capacity)) {
                mk_sense_buffer(scp, ILLEGAL_REQUEST, LBA_OUT_OF_RANGE, 0);
                return check_condition_result;
        }
        /* transfer length excessive (tie in to block limits VPD page) */
        if (unlikely(num > sdebug_store_sectors)) {
                /* needs work to find which cdb byte 'num' comes from */
                mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
                return check_condition_result;
        }

        if (unlikely((SDEBUG_OPT_MEDIUM_ERR & sdebug_opts) &&
                     (lba <= (sdebug_medium_error_start + sdebug_medium_error_count - 1)) &&
                     ((lba + num) > sdebug_medium_error_start))) {
                /* claim unrecoverable read error */
                mk_sense_buffer(scp, MEDIUM_ERROR, UNRECOVERED_READ_ERR, 0);
                /* set info field and valid bit for fixed descriptor */
                if (0x70 == (scp->sense_buffer[0] & 0x7f)) {
                        scp->sense_buffer[0] |= 0x80;   /* Valid bit */
                        ret = (lba < OPT_MEDIUM_ERR_ADDR)
                              ? OPT_MEDIUM_ERR_ADDR : (int)lba;
                        put_unaligned_be32(ret, scp->sense_buffer + 3);
                }
                scsi_set_resid(scp, scsi_bufflen(scp));
                return check_condition_result;
        }

        read_lock_irqsave(&atomic_rw, iflags);

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

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

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

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

        if (unlikely(sqcp)) {
                if (sqcp->inj_recovered) {
                        mk_sense_buffer(scp, RECOVERED_ERROR,
                                        THRESHOLD_EXCEEDED, 0);
                        return check_condition_result;
                } else if (sqcp->inj_transport) {
                        mk_sense_buffer(scp, ABORTED_COMMAND,
                                        TRANSPORT_PROBLEM, ACK_NAK_TO);
                        return check_condition_result;
                } else if (sqcp->inj_dif) {
                        /* Logical block guard check failed */
                        mk_sense_buffer(scp, ABORTED_COMMAND, 0x10, 1);
                        return illegal_condition_result;
                } else if (sqcp->inj_dix) {
                        mk_sense_buffer(scp, ILLEGAL_REQUEST, 0x10, 1);
                        return illegal_condition_result;
                }
        }
        return 0;
}

static 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 t10_pi_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 t10_pi_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, sdebug_sector_size);
                                goto out;
                        }

                        sector++;
                        ei_lba++;
                        dpage_offset += sdebug_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 (sdebug_unmap_alignment)
                lba += sdebug_unmap_granularity - sdebug_unmap_alignment;
        sector_div(lba, sdebug_unmap_granularity);
        return lba;
}

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

        if (sdebug_unmap_alignment)
                lba -= sdebug_unmap_granularity - sdebug_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 + sdebug_unmap_granularity <= end &&
                    index < map_size) {
                        clear_bit(index, map_storep);
                        if (sdebug_lbprz) {  /* for LBPRZ=2 return 0xff_s */
                                memset(fake_storep +
                                       lba * sdebug_sector_size,
                                       (sdebug_lbprz & 1) ? 0 : 0xff,
                                       sdebug_sector_size *
                                       sdebug_unmap_granularity);
                        }
                        if (dif_storep) {
                                memset(dif_storep + lba, 0xff,
                                       sizeof(*dif_storep) *
                                       sdebug_unmap_granularity);
                        }
                }
                lba = map_index_to_lba(index + 1);
        }
}

static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
{
        u8 *cmd = scp->cmnd;
        u64 lba;
        u32 num;
        u32 ei_lba;
        unsigned long iflags;
        int ret;
        bool check_prot;

        switch (cmd[0]) {
        case WRITE_16:
                ei_lba = 0;
                lba = get_unaligned_be64(cmd + 2);
                num = get_unaligned_be32(cmd + 10);
                check_prot = true;
                break;
        case WRITE_10:
                ei_lba = 0;
                lba = get_unaligned_be32(cmd + 2);
                num = get_unaligned_be16(cmd + 7);
                check_prot = true;
                break;
        case WRITE_6:
                ei_lba = 0;
                lba = (u32)cmd[3] | (u32)cmd[2] << 8 |
                      (u32)(cmd[1] & 0x1f) << 16;
                num = (0 == cmd[4]) ? 256 : cmd[4];