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

#include <linux/module.h>

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

#include <net/checksum.h>

#include <asm/unaligned.h>

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

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

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

#define MY_NAME "scsi_debug"

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

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


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

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

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

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

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

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

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

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

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

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

#define DEV_READONLY(TGT)      (0)

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

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

#define SDEBUG_MAX_PARTS 4

#define SCSI_DEBUG_MAX_CMD_LEN 32

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

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

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

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

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


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

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


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

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

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

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

static struct bus_type pseudo_lld_bus;

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

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

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

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

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

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

        return fake_storep + lba * scsi_debug_sector_size;
}

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

        return dif_storep + sector;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return 0;
}

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

        return scsi_sg_copy_to_buffer(scp, arr, arr_len);
}


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

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

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


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

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

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

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

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

        return num;
}

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

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

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

        return num;
}


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

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


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

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

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

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

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

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

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

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

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

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

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

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

        return sizeof(vpdb0_data);
}

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

        return 0x3c;
}

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

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

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

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

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

        return 0x4;
}

#define SDEBUG_LONG_INQ_SZ 96
#define SDEBUG_MAX_INQ_ARR_SZ 584

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

        alloc_len = (cmd[3] << 8) + cmd[4];
        arr = kzalloc(SDEBUG_MAX_INQ_ARR_SZ, GFP_ATOMIC);
        if (! arr)
                return DID_REQUEUE << 16;
        if (devip->wlun)
                pq_pdt = 0x1e;  /* present, wlun */
        else if (scsi_debug_no_lun_0 && (0 == devip->lun))
                pq_pdt = 0x7f;  /* not present, no device type */
        else
                pq_pdt = (scsi_debug_ptype & 0x1f);
        arr[0] = pq_pdt;
        if (0x2 & cmd[1]) {  /* CMDDT bit set */
                mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB,
                                0);
                kfree(arr);
                return check_condition_result;
        } else if (0x1 & cmd[1]) {  /* EVPD bit set */
                int lu_id_num, port_group_id, target_dev_id, len;
                char lu_id_str[6];
                int host_no = devip->sdbg_host->shost->host_no;
                
                port_group_id = (((host_no + 1) & 0x7f) << 8) +
                    (devip->channel & 0x7f);
                if (0 == scsi_debug_vpd_use_hostno)
                        host_no = 0;
                lu_id_num = devip->wlun ? -1 : (((host_no + 1) * 2000) +
                            (devip->target * 1000) + devip->lun);
                target_dev_id = ((host_no + 1) * 2000) +
                                 (devip->target * 1000) - 3;
                len = scnprintf(lu_id_str, 6, "%d", lu_id_num);
                if (0 == cmd[2]) { /* supported vital product data pages */
                        arr[1] = cmd[2];        /*sanity */
                        n = 4;
                        arr[n++] = 0x0;   /* this page */
                        arr[n++] = 0x80;  /* unit serial number */
                        arr[n++] = 0x83;  /* device identification */
                        arr[n++] = 0x84;  /* software interface ident. */
                        arr[n++] = 0x85;  /* management network addresses */
                        arr[n++] = 0x86;  /* extended inquiry */
                        arr[n++] = 0x87;  /* mode page policy */
                        arr[n++] = 0x88;  /* SCSI ports */
                        arr[n++] = 0x89;  /* ATA information */
                        arr[n++] = 0xb0;  /* Block limits (SBC) */
                        arr[n++] = 0xb1;  /* Block characteristics (SBC) */
                        if (scsi_debug_lbp()) /* Logical Block Prov. (SBC) */
                                arr[n++] = 0xb2;
                        arr[3] = n - 4;   /* number of supported VPD pages */
                } else if (0x80 == cmd[2]) { /* unit serial number */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = len;
                        memcpy(&arr[4], lu_id_str, len);
                } else if (0x83 == cmd[2]) { /* device identification */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_83(&arr[4], port_group_id,
                                                 target_dev_id, lu_id_num,
                                                 lu_id_str, len);
                } else if (0x84 == cmd[2]) { /* Software interface ident. */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_84(&arr[4]);
                } else if (0x85 == cmd[2]) { /* Management network addresses */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_85(&arr[4]);
                } else if (0x86 == cmd[2]) { /* extended inquiry */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = 0x3c;  /* number of following entries */
                        if (scsi_debug_dif == SD_DIF_TYPE3_PROTECTION)

                                arr[4] = 0x4;   /* SPT: GRD_CHK:1 */
                        else if (scsi_debug_dif)
                                arr[4] = 0x5;   /* SPT: GRD_CHK:1, REF_CHK:1 */
                        else
                                arr[4] = 0x0;   /* no protection stuff */
                        arr[5] = 0x7;   /* head of q, ordered + simple q's */
                } else if (0x87 == cmd[2]) { /* mode page policy */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = 0x8;   /* number of following entries */
                        arr[4] = 0x2;   /* disconnect-reconnect mp */
                        arr[6] = 0x80;  /* mlus, shared */
                        arr[8] = 0x18;   /* protocol specific lu */
                        arr[10] = 0x82;  /* mlus, per initiator port */
                } else if (0x88 == cmd[2]) { /* SCSI Ports */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_88(&arr[4], target_dev_id);
                } else if (0x89 == cmd[2]) { /* ATA information */
                        arr[1] = cmd[2];        /*sanity */
                        n = inquiry_evpd_89(&arr[4]);
                        arr[2] = (n >> 8);
                        arr[3] = (n & 0xff);
                } else if (0xb0 == cmd[2]) { /* Block limits (SBC) */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_b0(&arr[4]);
                } else if (0xb1 == cmd[2]) { /* Block characteristics (SBC) */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_b1(&arr[4]);
                } else if (0xb2 == cmd[2]) { /* Logical Block Prov. (SBC) */
                        arr[1] = cmd[2];        /*sanity */
                        arr[3] = inquiry_evpd_b2(&arr[4]);
                } else {
                        /* Illegal request, invalid field in cdb */
                        mk_sense_buffer(scp, ILLEGAL_REQUEST,
                                        INVALID_FIELD_IN_CDB, 0);
                        kfree(arr);
                        return check_condition_result;
                }
                len = min(((arr[2] << 8) + arr[3]) + 4, alloc_len);
                ret = fill_from_dev_buffer(scp, arr,
                            min(len, SDEBUG_MAX_INQ_ARR_SZ));
                kfree(arr);
                return ret;
        }
        /* drops through here for a standard inquiry */
        arr[1] = scsi_debug_removable ? 0x80 : 0;       /* Removable disk */
        arr[2] = scsi_debug_scsi_level;
        arr[3] = 2;    /* response_data_format==2 */
        arr[4] = SDEBUG_LONG_INQ_SZ - 5;
        arr[5] = scsi_debug_dif ? 1 : 0; /* PROTECT bit */
        if (0 == scsi_debug_vpd_use_hostno)
                arr[5] = 0x10; /* claim: implicit TGPS */
        arr[6] = 0x10; /* claim: MultiP */
        /* arr[6] |= 0x40; ... claim: EncServ (enclosure services) */
        arr[7] = 0xa; /* claim: LINKED + CMDQUE */
        memcpy(&arr[8], inq_vendor_id, 8);
        memcpy(&arr[16], inq_product_id, 16);
        memcpy(&arr[32], inq_product_rev, 4);
        /* version descriptors (2 bytes each) follow */
        arr[58] = 0x0; arr[59] = 0xa2;  /* SAM-5 rev 4 */
        arr[60] = 0x4; arr[61] = 0x68;  /* SPC-4 rev 37 */
        n = 62;
        if (scsi_debug_ptype == 0) {
                arr[n++] = 0x4; arr[n++] = 0xc5; /* SBC-4 rev 36 */
        } else if (scsi_debug_ptype == 1) {
                arr[n++] = 0x5; arr[n++] = 0x25; /* SSC-4 rev 3 */
        }
        arr[n++] = 0x20; arr[n++] = 0xe6;  /* SPL-3 rev 7 */
        ret = fill_from_dev_buffer(scp, arr,
                            min(alloc_len, SDEBUG_LONG_INQ_SZ));
        kfree(arr);
        return ret;
}

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

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

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

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

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

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

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

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

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

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

        arr[15] = scsi_debug_lowest_aligned & 0xff;

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

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

#define SDEBUG_MAX_TGTPGS_ARR_SZ 1412

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


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

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

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

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


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

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

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

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

#define SDEBUG_MAX_MSENSE_SZ 256

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

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

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

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

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

#define SDEBUG_MAX_MSELECT_SZ 512

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

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

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

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

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

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

#define SDEBUG_MAX_LSENSE_SZ 512

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

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

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

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

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

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

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

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

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

        return ret;
}

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

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

        return csum;
}

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

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

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

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

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

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

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

                paddr = miter.addr;

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

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

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

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

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

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

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

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

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

        return 0;
}

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

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

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

        read_lock_irqsave(&atomic_rw, iflags);

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

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

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

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

        return 0;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

        return 0;

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

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

        return lba;
}

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

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

        return lba;
}

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

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

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

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

        return mapped;
}

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

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

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

                lba = map_index_to_lba(index + 1);
        }
}

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

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

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

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

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

        write_lock_irqsave(&atomic_rw, iflags);

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

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

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

        return 0;
}

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

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

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

        write_lock_irqsave(&atomic_rw, iflags);

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

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

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

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

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

        return 0;
}

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

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

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

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

        descriptors = (payload_len - 8) / 16;

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

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

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

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

        write_lock_irqsave(&atomic_rw, iflags);

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

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

                unmap_region(lba, num);
        }

        ret = 0;

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

        return ret;
}

#define SDEBUG_GET_LBA_STATUS_LEN 32

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

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

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

        if (alloc_len < 24)
                return 0;

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

        mapped = map_state(lba, &num);

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

        return fill_from_dev_buffer(scmd, arr, SDEBUG_GET_LBA_STATUS_LEN);
}

#define SDEBUG_RLUN_ARR_SZ 256

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

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

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

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

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

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

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

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

        return 0;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        return open_devip;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

                pp->end_cyl = end_sec / heads_by_sects;
                pp->end_head = (end_sec - (pp->end_cyl * heads_by_sects))
                               / sdebug_sectors_per;