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scsi_debug.c

/*
 * 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://www.torque.net/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/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 <net/checksum.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 "sd.h"
#include "scsi_logging.h"

#define SCSI_DEBUG_VERSION "1.81"
static const char * scsi_debug_version_date = "20070104";

/* Additional Sense Code (ASC) */
#define NO_ADDITIONAL_SENSE 0x0
#define LOGICAL_UNIT_NOT_READY 0x4
#define UNRECOVERED_READ_ERR 0x11
#define PARAMETER_LIST_LENGTH_ERR 0x1a
#define INVALID_OPCODE 0x20
#define ADDR_OUT_OF_RANGE 0x21
#define INVALID_FIELD_IN_CDB 0x24
#define INVALID_FIELD_IN_PARAM_LIST 0x26
#define POWERON_RESET 0x29
#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

#define SDEBUG_TAGGED_QUEUING 0 /* 0 | MSG_SIMPLE_TAG | MSG_ORDERED_TAG */

/* 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_DELAY   1
#define DEF_DEV_SIZE_MB   8
#define DEF_EVERY_NTH   0
#define DEF_NUM_PARTS   0
#define DEF_OPTS   0
#define DEF_SCSI_LEVEL   5    /* INQUIRY, byte2 [5->SPC-3] */
#define DEF_PTYPE   0
#define DEF_D_SENSE   0
#define DEF_NO_LUN_0   0
#define DEF_VIRTUAL_GB   0
#define DEF_FAKE_RW     0
#define DEF_VPD_USE_HOSTNO 1
#define DEF_SECTOR_SIZE 512
#define DEF_DIX 0
#define DEF_DIF 0
#define DEF_GUARD 0
#define DEF_ATO 1
#define DEF_PHYSBLK_EXP 0
#define DEF_LOWEST_ALIGNED 0

/* 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
/* 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).
 */

/* 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 */

/* 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

static int scsi_debug_add_host = DEF_NUM_HOST;
static int scsi_debug_delay = DEF_DELAY;
static int scsi_debug_dev_size_mb = DEF_DEV_SIZE_MB;
static int scsi_debug_every_nth = DEF_EVERY_NTH;
static int scsi_debug_max_luns = DEF_MAX_LUNS;
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_opts = DEF_OPTS;
static int scsi_debug_scsi_level = DEF_SCSI_LEVEL;
static int scsi_debug_ptype = DEF_PTYPE; /* SCSI peripheral type (0==disk) */
static int scsi_debug_dsense = DEF_D_SENSE;
static int scsi_debug_no_lun_0 = DEF_NO_LUN_0;
static int scsi_debug_virtual_gb = DEF_VIRTUAL_GB;
static int scsi_debug_fake_rw = DEF_FAKE_RW;
static int scsi_debug_vpd_use_hostno = DEF_VPD_USE_HOSTNO;
static int scsi_debug_sector_size = DEF_SECTOR_SIZE;
static int scsi_debug_dix = DEF_DIX;
static int scsi_debug_dif = DEF_DIF;
static int scsi_debug_guard = DEF_GUARD;
static int scsi_debug_ato = DEF_ATO;
static int scsi_debug_physblk_exp = DEF_PHYSBLK_EXP;
static int scsi_debug_lowest_aligned = DEF_LOWEST_ALIGNED;

static int scsi_debug_cmnd_count = 0;

#define DEV_READONLY(TGT)      (0)
#define DEV_REMOVEABLE(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 SDEBUG_SENSE_LEN 32

#define SCSI_DEBUG_CANQUEUE  255
#define SCSI_DEBUG_MAX_CMD_LEN 16

00185 struct sdebug_dev_info {
      struct list_head dev_list;
      unsigned char sense_buff[SDEBUG_SENSE_LEN];     /* weak nexus */
      unsigned int channel;
      unsigned int target;
      unsigned int lun;
      struct sdebug_host_info *sdbg_host;
      unsigned int wlun;
      char reset;
      char stopped;
      char used;
};

00198 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);

typedef void (* done_funct_t) (struct scsi_cmnd *);

00213 struct sdebug_queued_cmd {
      int in_use;
      struct timer_list cmnd_timer;
      done_funct_t done_funct;
      struct scsi_cmnd * a_cmnd;
      int scsi_result;
};
static struct sdebug_queued_cmd queued_arr[SCSI_DEBUG_CANQUEUE];

static unsigned char * fake_storep; /* ramdisk storage */
static unsigned char *dif_storep;   /* protection info */

static int num_aborts = 0;
static int num_dev_resets = 0;
static int num_bus_resets = 0;
static int num_host_resets = 0;
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[] = "scsi_debug";

static struct bus_type pseudo_lld_bus;

static inline sector_t dif_offset(sector_t sector)
{
      return sector << 3;
}

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 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 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 sdebug_dev_info *devip, int key,
                      int asc, int asq)
{
      unsigned char *sbuff;

      sbuff = devip->sense_buff;
      memset(sbuff, 0, SDEBUG_SENSE_LEN);

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

      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug:    [sense_key,asc,ascq]: "
                  "[0x%x,0x%x,0x%x]\n", key, asc, asq);
}

static void get_data_transfer_info(unsigned char *cmd,
                           unsigned long long *lba, unsigned int *num)
{
      switch (*cmd) {
      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_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) {
            printk(KERN_INFO "scsi_debug: ioctl: cmd=0x%x\n", cmd);
      }
      return -EINVAL;
      /* return -ENOTTY; // correct return but upsets fdisk */
}

static int check_readiness(struct scsi_cmnd * SCpnt, int reset_only,
                     struct sdebug_dev_info * devip)
{
      if (devip->reset) {
            if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
                  printk(KERN_INFO "scsi_debug: Reporting Unit "
                         "attention: power on reset\n");
            devip->reset = 0;
            mk_sense_buffer(devip, UNIT_ATTENTION, POWERON_RESET, 0);
            return check_condition_result;
      }
      if ((0 == reset_only) && devip->stopped) {
            if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
                  printk(KERN_INFO "scsi_debug: Reporting Not "
                         "ready: initializing command required\n");
            mk_sense_buffer(devip, NOT_READY, LOGICAL_UNIT_NOT_READY,
                        0x2);
            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);
      if (sdb->resid)
            sdb->resid -= act_len;
      else
            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 = "0004";

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,
};

static int inquiry_evpd_84(unsigned char * arr)
{
      memcpy(arr, vpd84_data, sizeof(vpd84_data));
      return sizeof(vpd84_data);
}

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,
};

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,
};

static int inquiry_evpd_b0(unsigned char * arr)
{
      unsigned int gran;

      memcpy(arr, vpdb0_data, sizeof(vpdb0_data));
      gran = 1 << scsi_debug_physblk_exp;
      arr[2] = (gran >> 8) & 0xff;
      arr[3] = gran & 0xff;
      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;
      }
      return sizeof(vpdb0_data);
}

static int inquiry_evpd_b1(unsigned char *arr)
{
      memset(arr, 0, 0x3c);
      arr[0] = 0;
      arr[1] = 1;

      return 0x3c;
}

#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 = (unsigned char *)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(devip, 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) */
                  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 {
                  /* Illegal request, invalid field in cdb */
                  mk_sense_buffer(devip, 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] = DEV_REMOVEABLE(target) ? 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] = 0x77; /* SAM-3 ANSI */
      arr[60] = 0x3; arr[61] = 0x14;  /* SPC-3 ANSI */
      n = 62;
      if (scsi_debug_ptype == 0) {
            arr[n++] = 0x3; arr[n++] = 0x3d; /* SBC-2 ANSI */
      } else if (scsi_debug_ptype == 1) {
            arr[n++] = 0x3; arr[n++] = 0x60; /* SSC-2 no version */
      }
      arr[n++] = 0xc; arr[n++] = 0xf;  /* SAS-1.1 rev 10 */
      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 = (unsigned char *)scp->cmnd;
      unsigned char arr[SDEBUG_SENSE_LEN];
      int want_dsense;
      int len = 18;

      memset(arr, 0, sizeof(arr));
      if (devip->reset == 1)
            mk_sense_buffer(devip, 0, NO_ADDITIONAL_SENSE, 0);
      want_dsense = !!(cmd[1] & 1) || scsi_debug_dsense;
      sbuff = devip->sense_buff;
      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, SDEBUG_SENSE_LEN);
            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(devip, 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 = (unsigned char *)scp->cmnd;
      int power_cond, errsts, start;

      if ((errsts = check_readiness(scp, 1, devip)))
            return errsts;
      power_cond = (cmd[4] & 0xf0) >> 4;
      if (power_cond) {
            mk_sense_buffer(devip, 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 2048 * 1024 * (sector_t)scsi_debug_virtual_gb;
      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;

      if ((errsts = check_readiness(scp, 1, devip)))
            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 = (unsigned char *)scp->cmnd;
      unsigned char arr[SDEBUG_READCAP16_ARR_SZ];
      unsigned long long capac;
      int errsts, k, alloc_len;

      if ((errsts = check_readiness(scp, 1, devip)))
            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;
      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 = (unsigned char *)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 (DEV_REMOVEABLE(target))
            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 caching_pg[] = {0x8, 18, 0x14, 0, 0xff, 0xff, 0, 0,
            0xff, 0xff, 0xff, 0xff, 0x80, 0x14, 0, 0,     0, 0, 0, 0};

      memcpy(p, caching_pg, sizeof(caching_pg));
      if (1 == pcontrol)
            memset(p + 2, 0, sizeof(caching_pg) - 2);
      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 = (unsigned char *)scp->cmnd;

      if ((errsts = check_readiness(scp, 1, devip)))
            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(devip, 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(devip, 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(devip, 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(devip, ILLEGAL_REQUEST,
                              INVALID_FIELD_IN_CDB, 0);
                  return check_condition_result;
                }
            offset += len;
            break;
      default:
            mk_sense_buffer(devip, 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 = (unsigned char *)scp->cmnd;

      if ((errsts = check_readiness(scp, 1, devip)))
            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(devip, 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))
                printk(KERN_INFO "scsi_debug: mode_select: cdb indicated=%d, "
                       " IO sent=%d bytes\n", 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(devip, 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(devip, 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(devip, ILLEGAL_REQUEST,
                        PARAMETER_LIST_LENGTH_ERR, 0);
            return check_condition_result;
      }
      switch (mpage) {
      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);
                  return 0;
            }
            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);
                  return 0;
            }
            break;
      default:
            break;
      }
      mk_sense_buffer(devip, ILLEGAL_REQUEST,
                  INVALID_FIELD_IN_PARAM_LIST, 0);
      return check_condition_result;
}

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 = (unsigned char *)scp->cmnd;

      if ((errsts = check_readiness(scp, 1, devip)))
            return errsts;
      memset(arr, 0, sizeof(arr));
      ppc = cmd[1] & 0x2;
      sp = cmd[1] & 0x1;
      if (ppc || sp) {
            mk_sense_buffer(devip, 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(devip, 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(devip, ILLEGAL_REQUEST,
                              INVALID_FIELD_IN_CDB, 0);
                  return check_condition_result;
            }
      } else {
            mk_sense_buffer(devip, 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 sdebug_dev_info *devi,
                              unsigned long long lba, unsigned int num)
{
      if (lba + num > sdebug_capacity) {
            mk_sense_buffer(devi, 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(devi, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0);
            return check_condition_result;
      }
      return 0;
}

static int do_device_access(struct scsi_cmnd *scmd,
                      struct sdebug_dev_info *devi,
                      unsigned long long lba, unsigned int num, int write)
{
      int ret;
      unsigned int block, rest = 0;
      int (*func)(struct scsi_cmnd *, unsigned char *, int);

      func = write ? fetch_to_dev_buffer : fill_from_dev_buffer;

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

      ret = func(scmd, fake_storep + (block * scsi_debug_sector_size),
               (num - rest) * scsi_debug_sector_size);
      if (!ret && rest)
            ret = func(scmd, fake_storep, rest * scsi_debug_sector_size);

      return ret;
}

static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
                      unsigned int sectors)
{
      unsigned int i, resid;
      struct scatterlist *psgl;
      struct sd_dif_tuple *sdt;
      sector_t sector;
      sector_t tmp_sec = start_sec;
      void *paddr;

      start_sec = do_div(tmp_sec, sdebug_store_sectors);

      sdt = (struct sd_dif_tuple *)(dif_storep + dif_offset(start_sec));

      for (i = 0 ; i < sectors ; i++) {
            u16 csum;

            if (sdt[i].app_tag == 0xffff)
                  continue;

            sector = start_sec + i;

            switch (scsi_debug_guard) {
            case 1:
                  csum = ip_compute_csum(fake_storep +
                                     sector * scsi_debug_sector_size,
                                     scsi_debug_sector_size);
                  break;
            case 0:
                  csum = crc_t10dif(fake_storep +
                                sector * scsi_debug_sector_size,
                                scsi_debug_sector_size);
                  csum = cpu_to_be16(csum);
                  break;
            default:
                  BUG();
            }

            if (sdt[i].guard_tag != csum) {
                  printk(KERN_ERR "%s: GUARD check failed on sector %lu" \
                         " rcvd 0x%04x, data 0x%04x\n", __func__,
                         (unsigned long)sector,
                         be16_to_cpu(sdt[i].guard_tag),
                         be16_to_cpu(csum));
                  dif_errors++;
                  return 0x01;
            }

            if (scsi_debug_dif != SD_DIF_TYPE3_PROTECTION &&
                be32_to_cpu(sdt[i].ref_tag) != (sector & 0xffffffff)) {
                  printk(KERN_ERR "%s: REF check failed on sector %lu\n",
                         __func__, (unsigned long)sector);
                  dif_errors++;
                  return 0x03;
            }
      }

      resid = sectors * 8; /* Bytes of protection data to copy into sgl */
      sector = start_sec;

      scsi_for_each_prot_sg(SCpnt, psgl, scsi_prot_sg_count(SCpnt), i) {
            int len = min(psgl->length, resid);

            paddr = kmap_atomic(sg_page(psgl), KM_IRQ0) + psgl->offset;
            memcpy(paddr, dif_storep + dif_offset(sector), len);

            sector += len >> 3;
            if (sector >= sdebug_store_sectors) {
                  /* Force wrap */
                  tmp_sec = sector;
                  sector = do_div(tmp_sec, sdebug_store_sectors);
            }
            resid -= len;
            kunmap_atomic(paddr, KM_IRQ0);
      }

      dix_reads++;

      return 0;
}

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

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

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

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

            if (prot_ret) {
                  mk_sense_buffer(devip, ABORTED_COMMAND, 0x10, prot_ret);
                  return illegal_condition_result;
            }
      }

      read_lock_irqsave(&atomic_rw, iflags);
      ret = do_device_access(SCpnt, devip, lba, num, 0);
      read_unlock_irqrestore(&atomic_rw, iflags);
      return ret;
}

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

      printk(KERN_ERR ">>> Sector Dump <<<\n");

      for (i = 0 ; i < len ; i += 16) {
            printk(KERN_ERR "%04d: ", i);

            for (j = 0 ; j < 16 ; j++) {
                  unsigned char c = buf[i+j];
                  if (c >= 0x20 && c < 0x7e)
                        printk(" %c ", buf[i+j]);
                  else
                        printk("%02x ", buf[i+j]);
            }

            printk("\n");
      }
}

static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec,
                       unsigned int sectors)
{
      int i, j, ret;
      struct sd_dif_tuple *sdt;
      struct scatterlist *dsgl = scsi_sglist(SCpnt);
      struct scatterlist *psgl = scsi_prot_sglist(SCpnt);
      void *daddr, *paddr;
      sector_t tmp_sec = start_sec;
      sector_t sector;
      int ppage_offset;
      unsigned short csum;

      sector = do_div(tmp_sec, sdebug_store_sectors);

      if (((SCpnt->cmnd[1] >> 5) & 7) != 1) {
            printk(KERN_WARNING "scsi_debug: WRPROTECT != 1\n");
            return 0;
      }

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

      paddr = kmap_atomic(sg_page(psgl), KM_IRQ1) + psgl->offset;
      ppage_offset = 0;

      /* For each data page */
      scsi_for_each_sg(SCpnt, dsgl, scsi_sg_count(SCpnt), i) {
            daddr = kmap_atomic(sg_page(dsgl), KM_IRQ0) + dsgl->offset;

            /* For each sector-sized chunk in data page */
            for (j = 0 ; j < dsgl->length ; j += scsi_debug_sector_size) {

                  /* If we're at the end of the current
                   * protection page advance to the next one
                   */
                  if (ppage_offset >= psgl->length) {
                        kunmap_atomic(paddr, KM_IRQ1);
                        psgl = sg_next(psgl);
                        BUG_ON(psgl == NULL);
                        paddr = kmap_atomic(sg_page(psgl), KM_IRQ1)
                              + psgl->offset;
                        ppage_offset = 0;
                  }

                  sdt = paddr + ppage_offset;

                  switch (scsi_debug_guard) {
                  case 1:
                        csum = ip_compute_csum(daddr,
                                           scsi_debug_sector_size);
                        break;
                  case 0:
                        csum = cpu_to_be16(crc_t10dif(daddr,
                                          scsi_debug_sector_size));
                        break;
                  default:
                        BUG();
                        ret = 0;
                        goto out;
                  }

                  if (sdt->guard_tag != csum) {
                        printk(KERN_ERR
                               "%s: GUARD check failed on sector %lu " \
                               "rcvd 0x%04x, calculated 0x%04x\n",
                               __func__, (unsigned long)sector,
                               be16_to_cpu(sdt->guard_tag),
                               be16_to_cpu(csum));
                        ret = 0x01;
                        dump_sector(daddr, scsi_debug_sector_size);
                        goto out;
                  }

                  if (scsi_debug_dif != SD_DIF_TYPE3_PROTECTION &&
                      be32_to_cpu(sdt->ref_tag)
                      != (start_sec & 0xffffffff)) {
                        printk(KERN_ERR
                               "%s: REF check failed on sector %lu\n",
                               __func__, (unsigned long)sector);
                        ret = 0x03;
                        dump_sector(daddr, scsi_debug_sector_size);
                        goto out;
                  }

                  /* Would be great to copy this in bigger
                   * chunks.  However, for the sake of
                   * correctness we need to verify each sector
                   * before writing it to "stable" storage
                   */
                  memcpy(dif_storep + dif_offset(sector), sdt, 8);

                  sector++;

                  if (sector == sdebug_store_sectors)
                        sector = 0; /* Force wrap */

                  start_sec++;
                  daddr += scsi_debug_sector_size;
                  ppage_offset += sizeof(struct sd_dif_tuple);
            }

            kunmap_atomic(daddr, KM_IRQ0);
      }

      kunmap_atomic(paddr, KM_IRQ1);

      dix_writes++;

      return 0;

out:
      dif_errors++;
      kunmap_atomic(daddr, KM_IRQ0);
      kunmap_atomic(paddr, KM_IRQ1);
      return ret;
}

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

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

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

            if (prot_ret) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST, 0x10, prot_ret);
                  return illegal_condition_result;
            }
      }

      write_lock_irqsave(&atomic_rw, iflags);
      ret = do_device_access(SCpnt, devip, lba, num, 1);
      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))
            printk(KERN_INFO "scsi_debug: write: cdb indicated=%u, "
                   " IO sent=%d bytes\n", num * scsi_debug_sector_size, ret);
      return 0;
}

#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, wlun, lun;
      unsigned char *cmd = (unsigned char *)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(devip, 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 i, j, ret = -1;
      unsigned char *kaddr, *buf;
      unsigned int offset;
      struct scatterlist *sg;
      struct scsi_data_buffer *sdb = scsi_in(scp);

      /* better not to use temporary buffer. */
      buf = kmalloc(scsi_bufflen(scp), GFP_ATOMIC);
      if (!buf)
            return ret;

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

      offset = 0;
      for_each_sg(sdb->table.sgl, sg, sdb->table.nents, i) {
            kaddr = (unsigned char *)kmap_atomic(sg_page(sg), KM_USER0);
            if (!kaddr)
                  goto out;

            for (j = 0; j < sg->length; j++)
                  *(kaddr + sg->offset + j) ^= *(buf + offset + j);

            offset += sg->length;
            kunmap_atomic(kaddr, KM_USER0);
      }
      ret = 0;
out:
      kfree(buf);

      return ret;
}

/* When timer goes off this function is called. */
static void timer_intr_handler(unsigned long indx)
{
      struct sdebug_queued_cmd * sqcp;
      unsigned long iflags;

      if (indx >= SCSI_DEBUG_CANQUEUE) {
            printk(KERN_ERR "scsi_debug:timer_intr_handler: indx too "
                   "large\n");
            return;
      }
      spin_lock_irqsave(&queued_arr_lock, iflags);
      sqcp = &queued_arr[(int)indx];
      if (! sqcp->in_use) {
            printk(KERN_ERR "scsi_debug:timer_intr_handler: Unexpected "
                   "interrupt\n");
            spin_unlock_irqrestore(&queued_arr_lock, iflags);
            return;
      }
      sqcp->in_use = 0;
      if (sqcp->done_funct) {
            sqcp->a_cmnd->result = sqcp->scsi_result;
            sqcp->done_funct(sqcp->a_cmnd); /* callback to mid level */
      }
      sqcp->done_funct = NULL;
      spin_unlock_irqrestore(&queued_arr_lock, iflags);
}


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) {
                printk(KERN_ERR "Host info NULL\n");
            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;
      open_devip->reset = 1;
      open_devip->used = 1;
      memset(open_devip->sense_buff, 0, SDEBUG_SENSE_LEN);
      if (scsi_debug_dsense)
            open_devip->sense_buff[0] = 0x72;
      else {
            open_devip->sense_buff[0] = 0x70;
            open_devip->sense_buff[7] = 0xa;
      }
      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 %u>\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 %u>\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;
      if (sdp->host->cmd_per_lun)
            scsi_adjust_queue_depth(sdp, SDEBUG_TAGGED_QUEUING,
                              sdp->host->cmd_per_lun);
      blk_queue_max_segment_size(sdp->request_queue, 256 * 1024);
      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 %u>\n",
                   sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
      if (devip) {
            /* make this slot avaliable for re-use */
            devip->used = 0;
            sdp->hostdata = NULL;
      }
}

/* Returns 1 if found 'cmnd' and deleted its timer. else returns 0 */
static int stop_queued_cmnd(struct scsi_cmnd *cmnd)
{
      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];
            if (sqcp->in_use && (cmnd == sqcp->a_cmnd)) {
                  del_timer_sync(&sqcp->cmnd_timer);
                  sqcp->in_use = 0;
                  sqcp->a_cmnd = NULL;
                  break;
            }
      }
      spin_unlock_irqrestore(&queued_arr_lock, iflags);
      return (k < SCSI_DEBUG_CANQUEUE) ? 1 : 0;
}

/* Deletes (stops) timers of all queued commands */
static void stop_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];
            if (sqcp->in_use && sqcp->a_cmnd) {
                  del_timer_sync(&sqcp->cmnd_timer);
                  sqcp->in_use = 0;
                  sqcp->a_cmnd = NULL;
            }
      }
      spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

static int scsi_debug_abort(struct scsi_cmnd * SCpnt)
{
      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: abort\n");
      ++num_aborts;
      stop_queued_cmnd(SCpnt);
      return SUCCESS;
}

static int scsi_debug_biosparam(struct scsi_device *sdev,
            struct block_device * bdev, sector_t capacity, int *info)
{
      int res;
      unsigned char *buf;

      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: biosparam\n");
      buf = scsi_bios_ptable(bdev);
      if (buf) {
            res = scsi_partsize(buf, capacity,
                            &info[2], &info[0], &info[1]);
            kfree(buf);
            if (! res)
                  return res;
      }
      info[0] = sdebug_heads;
      info[1] = sdebug_sectors_per;
      info[2] = sdebug_cylinders_per;
      return 0;
}

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

      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: device_reset\n");
      ++num_dev_resets;
      if (SCpnt) {
            devip = devInfoReg(SCpnt->device);
            if (devip)
                  devip->reset = 1;
      }
      return SUCCESS;
}

static int scsi_debug_bus_reset(struct scsi_cmnd * SCpnt)
{
      struct sdebug_host_info *sdbg_host;
        struct sdebug_dev_info * dev_info;
        struct scsi_device * sdp;
        struct Scsi_Host * hp;

      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: bus_reset\n");
      ++num_bus_resets;
      if (SCpnt && ((sdp = SCpnt->device)) && ((hp = sdp->host))) {
            sdbg_host = *(struct sdebug_host_info **)shost_priv(hp);
            if (sdbg_host) {
                  list_for_each_entry(dev_info,
                                            &sdbg_host->dev_info_list,
                                            dev_list)
                        dev_info->reset = 1;
            }
      }
      return SUCCESS;
}

static int scsi_debug_host_reset(struct scsi_cmnd * SCpnt)
{
      struct sdebug_host_info * sdbg_host;
        struct sdebug_dev_info * dev_info;

      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: host_reset\n");
      ++num_host_resets;
        spin_lock(&sdebug_host_list_lock);
        list_for_each_entry(sdbg_host, &sdebug_host_list, host_list) {
                list_for_each_entry(dev_info, &sdbg_host->dev_info_list,
                                    dev_list)
                        dev_info->reset = 1;
        }
        spin_unlock(&sdebug_host_list_lock);
      stop_all_queued();
      return SUCCESS;
}

/* Initializes timers in queued array */
static void __init init_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];
            init_timer(&sqcp->cmnd_timer);
            sqcp->in_use = 0;
            sqcp->a_cmnd = NULL;
      }
      spin_unlock_irqrestore(&queued_arr_lock, iflags);
}

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;
            printk(KERN_WARNING "scsi_debug:build_parts: reducing "
                            "partitions to %d\n", SDEBUG_MAX_PARTS);
      }
      num_sectors = (int)sdebug_store_sectors;
      sectors_per_part = (num_sectors - sdebug_sectors_per)
                     / scsi_debug_num_parts;
      heads_by_sects = sdebug_heads * sdebug_sectors_per;
        starts[0] = sdebug_sectors_per;
      for (k = 1; k < scsi_debug_num_parts; ++k)
            starts[k] = ((k * sectors_per_part) / heads_by_sects)
                      * heads_by_sects;
      starts[scsi_debug_num_parts] = num_sectors;
      starts[scsi_debug_num_parts + 1] = 0;

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

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

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

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

static int schedule_resp(struct scsi_cmnd * cmnd,
                   struct sdebug_dev_info * devip,
                   done_funct_t done, int scsi_result, int delta_jiff)
{
      if ((SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) && cmnd) {
            if (scsi_result) {
                  struct scsi_device * sdp = cmnd->device;

                  printk(KERN_INFO "scsi_debug:    <%u %u %u %u> "
                         "non-zero result=0x%x\n", sdp->host->host_no,
                         sdp->channel, sdp->id, sdp->lun, scsi_result);
            }
      }
      if (cmnd && devip) {
            /* simulate autosense by this driver */
            if (SAM_STAT_CHECK_CONDITION == (scsi_result & 0xff))
                  memcpy(cmnd->sense_buffer, devip->sense_buff,
                         (SCSI_SENSE_BUFFERSIZE > SDEBUG_SENSE_LEN) ?
                         SDEBUG_SENSE_LEN : SCSI_SENSE_BUFFERSIZE);
      }
      if (delta_jiff <= 0) {
            if (cmnd)
                  cmnd->result = scsi_result;
            if (done)
                  done(cmnd);
            return 0;
      } else {
            unsigned long iflags;
            int k;
            struct sdebug_queued_cmd * sqcp = NULL;

            spin_lock_irqsave(&queued_arr_lock, iflags);
            for (k = 0; k < SCSI_DEBUG_CANQUEUE; ++k) {
                  sqcp = &queued_arr[k];
                  if (! sqcp->in_use)
                        break;
            }
            if (k >= SCSI_DEBUG_CANQUEUE) {
                  spin_unlock_irqrestore(&queued_arr_lock, iflags);
                  printk(KERN_WARNING "scsi_debug: can_queue exceeded\n");
                  return 1;   /* report busy to mid level */
            }
            sqcp->in_use = 1;
            sqcp->a_cmnd = cmnd;
            sqcp->scsi_result = scsi_result;
            sqcp->done_funct = done;
            sqcp->cmnd_timer.function = timer_intr_handler;
            sqcp->cmnd_timer.data = k;
            sqcp->cmnd_timer.expires = jiffies + delta_jiff;
            add_timer(&sqcp->cmnd_timer);
            spin_unlock_irqrestore(&queued_arr_lock, iflags);
            if (cmnd)
                  cmnd->result = 0;
            return 0;
      }
}
/* Note: The following macros create attribute files in the
   /sys/module/scsi_debug/parameters directory. Unfortunately this
   driver is unaware of a change and cannot trigger auxiliary actions
   as it can when the corresponding attribute in the
   /sys/bus/pseudo/drivers/scsi_debug directory is changed.
 */
module_param_named(add_host, scsi_debug_add_host, int, S_IRUGO | S_IWUSR);
module_param_named(delay, scsi_debug_delay, int, S_IRUGO | S_IWUSR);
module_param_named(dev_size_mb, scsi_debug_dev_size_mb, int, S_IRUGO);
module_param_named(dsense, scsi_debug_dsense, int, S_IRUGO | S_IWUSR);
module_param_named(every_nth, scsi_debug_every_nth, int, S_IRUGO | S_IWUSR);
module_param_named(fake_rw, scsi_debug_fake_rw, int, S_IRUGO | S_IWUSR);
module_param_named(max_luns, scsi_debug_max_luns, int, S_IRUGO | S_IWUSR);
module_param_named(no_lun_0, scsi_debug_no_lun_0, int, S_IRUGO | S_IWUSR);
module_param_named(num_parts, scsi_debug_num_parts, int, S_IRUGO);
module_param_named(num_tgts, scsi_debug_num_tgts, int, S_IRUGO | S_IWUSR);
module_param_named(opts, scsi_debug_opts, int, S_IRUGO | S_IWUSR);
module_param_named(ptype, scsi_debug_ptype, int, S_IRUGO | S_IWUSR);
module_param_named(scsi_level, scsi_debug_scsi_level, int, S_IRUGO);
module_param_named(virtual_gb, scsi_debug_virtual_gb, int, S_IRUGO | S_IWUSR);
module_param_named(vpd_use_hostno, scsi_debug_vpd_use_hostno, int,
               S_IRUGO | S_IWUSR);
module_param_named(sector_size, scsi_debug_sector_size, int, S_IRUGO);
module_param_named(dix, scsi_debug_dix, int, S_IRUGO);
module_param_named(dif, scsi_debug_dif, int, S_IRUGO);
module_param_named(guard, scsi_debug_guard, int, S_IRUGO);
module_param_named(ato, scsi_debug_ato, int, S_IRUGO);
module_param_named(physblk_exp, scsi_debug_physblk_exp, int, S_IRUGO);
module_param_named(lowest_aligned, scsi_debug_lowest_aligned, int, S_IRUGO);

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

MODULE_PARM_DESC(add_host, "0..127 hosts allowed(def=1)");
MODULE_PARM_DESC(delay, "# of jiffies to delay response(def=1)");
MODULE_PARM_DESC(dev_size_mb, "size in MB of ram shared by devs(def=8)");
MODULE_PARM_DESC(dsense, "use descriptor sense format(def=0 -> fixed)");
MODULE_PARM_DESC(every_nth, "timeout every nth command(def=0)");
MODULE_PARM_DESC(fake_rw, "fake reads/writes instead of copying (def=0)");
MODULE_PARM_DESC(max_luns, "number of LUNs per target to simulate(def=1)");
MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)");
MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");
MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)");
MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... (def=0)");
MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])");
MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=5[SPC-3])");
MODULE_PARM_DESC(virtual_gb, "virtual gigabyte size (def=0 -> use dev_size_mb)");
MODULE_PARM_DESC(vpd_use_hostno, "0 -> dev ids ignore hostno (def=1 -> unique dev ids)");
MODULE_PARM_DESC(sector_size, "logical block size in bytes (def=512)");
MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)");
MODULE_PARM_DESC(lowest_aligned, "lowest aligned lba (def=0)");
MODULE_PARM_DESC(dix, "data integrity extensions mask (def=0)");
MODULE_PARM_DESC(dif, "data integrity field type: 0-3 (def=0)");
MODULE_PARM_DESC(guard, "protection checksum: 0=crc, 1=ip (def=0)");
MODULE_PARM_DESC(ato, "application tag ownership: 0=disk 1=host (def=1)");

static char sdebug_info[256];

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

/* scsi_debug_proc_info
 * Used if the driver currently has no own support for /proc/scsi
 */
static int scsi_debug_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset,
                        int length, int inout)
{
      int len, pos, begin;
      int orig_length;

      orig_length = length;

      if (inout == 1) {
            char arr[16];
            int minLen = length > 15 ? 15 : length;

            if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
                  return -EACCES;
            memcpy(arr, buffer, minLen);
            arr[minLen] = '\0';
            if (1 != sscanf(arr, "%d", &pos))
                  return -EINVAL;
            scsi_debug_opts = pos;
            if (scsi_debug_every_nth != 0)
                        scsi_debug_cmnd_count = 0;
            return length;
      }
      begin = 0;
      pos = len = sprintf(buffer, "scsi_debug adapter driver, version "
          "%s [%s]\n"
          "num_tgts=%d, shared (ram) size=%d MB, opts=0x%x, "
          "every_nth=%d(curr:%d)\n"
          "delay=%d, max_luns=%d, scsi_level=%d\n"
          "sector_size=%d bytes, cylinders=%d, heads=%d, sectors=%d\n"
          "number of aborts=%d, device_reset=%d, bus_resets=%d, "
          "host_resets=%d\ndix_reads=%d dix_writes=%d dif_errors=%d\n",
          SCSI_DEBUG_VERSION, scsi_debug_version_date, scsi_debug_num_tgts,
          scsi_debug_dev_size_mb, scsi_debug_opts, scsi_debug_every_nth,
          scsi_debug_cmnd_count, scsi_debug_delay,
          scsi_debug_max_luns, scsi_debug_scsi_level,
          scsi_debug_sector_size, sdebug_cylinders_per, sdebug_heads,
          sdebug_sectors_per, num_aborts, num_dev_resets, num_bus_resets,
          num_host_resets, dix_reads, dix_writes, dif_errors);
      if (pos < offset) {
            len = 0;
            begin = pos;
      }
      *start = buffer + (offset - begin); /* Start of wanted data */
      len -= (offset - begin);
      if (len > length)
            len = length;
      return len;
}

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

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

        if (1 == sscanf(buf, "%10s", work)) {
            if ((1 == sscanf(work, "%d", &delay)) && (delay >= 0)) {
                  scsi_debug_delay = delay;
                  return count;
            }
      }
      return -EINVAL;
}
DRIVER_ATTR(delay, S_IRUGO | S_IWUSR, sdebug_delay_show,
          sdebug_delay_store);

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

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

        if (1 == sscanf(buf, "%10s", work)) {
            if (0 == strnicmp(work,"0x", 2)) {
                  if (1 == sscanf(&work[2], "%x", &opts))
                        goto opts_done;
            } else {
                  if (1 == sscanf(work, "%d", &opts))
                        goto opts_done;
            }
      }
      return -EINVAL;
opts_done:
      scsi_debug_opts = opts;
      scsi_debug_cmnd_count = 0;
      return count;
}
DRIVER_ATTR(opts, S_IRUGO | S_IWUSR, sdebug_opts_show,
          sdebug_opts_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_ptype = n;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(ptype, S_IRUGO | S_IWUSR, sdebug_ptype_show, sdebug_ptype_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_dsense = n;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(dsense, S_IRUGO | S_IWUSR, sdebug_dsense_show,
          sdebug_dsense_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_fake_rw = n;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(fake_rw, S_IRUGO | S_IWUSR, sdebug_fake_rw_show,
          sdebug_fake_rw_store);

static ssize_t sdebug_no_lun_0_show(struct device_driver * ddp, char * buf)
{
        return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_no_lun_0);
}
static ssize_t sdebug_no_lun_0_store(struct device_driver * ddp,
                             const char * buf, size_t count)
{
        int n;

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_no_lun_0 = n;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(no_lun_0, S_IRUGO | S_IWUSR, sdebug_no_lun_0_show,
          sdebug_no_lun_0_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_num_tgts = n;
            sdebug_max_tgts_luns();
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(num_tgts, S_IRUGO | S_IWUSR, sdebug_num_tgts_show,
          sdebug_num_tgts_store);

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

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

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &nth))) {
            scsi_debug_every_nth = nth;
            scsi_debug_cmnd_count = 0;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(every_nth, S_IRUGO | S_IWUSR, sdebug_every_nth_show,
          sdebug_every_nth_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_max_luns = n;
            sdebug_max_tgts_luns();
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(max_luns, S_IRUGO | S_IWUSR, sdebug_max_luns_show,
          sdebug_max_luns_store);

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

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

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

            sdebug_capacity = get_sdebug_capacity();

            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(virtual_gb, S_IRUGO | S_IWUSR, sdebug_virtual_gb_show,
          sdebug_virtual_gb_store);

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

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

      if (sscanf(buf, "%d", &delta_hosts) != 1)
            return -EINVAL;
      if (delta_hosts > 0) {
            do {
                  sdebug_add_adapter();
            } while (--delta_hosts);
      } else if (delta_hosts < 0) {
            do {
                  sdebug_remove_adapter();
            } while (++delta_hosts);
      }
      return count;
}
DRIVER_ATTR(add_host, S_IRUGO | S_IWUSR, sdebug_add_host_show,
          sdebug_add_host_store);

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

      if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
            scsi_debug_vpd_use_hostno = n;
            return count;
      }
      return -EINVAL;
}
DRIVER_ATTR(vpd_use_hostno, S_IRUGO | S_IWUSR, sdebug_vpd_use_hostno_show,
          sdebug_vpd_use_hostno_store);

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

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

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

static ssize_t sdebug_guard_show(struct device_driver *ddp, char *buf)
{
      return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_guard);
}
DRIVER_ATTR(guard, S_IRUGO, sdebug_guard_show, NULL);

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


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

      ret = driver_create_file(&sdebug_driverfs_driver, &driver_attr_add_host);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_delay);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_dev_size_mb);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_dsense);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_every_nth);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_fake_rw);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_max_luns);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_no_lun_0);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_num_parts);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_ptype);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_opts);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_virtual_gb);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_vpd_use_hostno);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_sector_size);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_dix);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_dif);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_guard);
      ret |= driver_create_file(&sdebug_driverfs_driver, &driver_attr_ato);
      return ret;
}

static void do_remove_driverfs_files(void)
{
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_ato);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_guard);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dif);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dix);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_sector_size);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_vpd_use_hostno);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_virtual_gb);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_scsi_level);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_opts);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_ptype);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_tgts);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_num_parts);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_no_lun_0);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_max_luns);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_fake_rw);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_every_nth);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dsense);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_dev_size_mb);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_delay);
      driver_remove_file(&sdebug_driverfs_driver, &driver_attr_add_host);
}

static void pseudo_0_release(struct device *dev)
{
      if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
            printk(KERN_INFO "scsi_debug: pseudo_0_release() called\n");
}

static struct device pseudo_primary = {
      .init_name  = "pseudo_0",
      .release    = pseudo_0_release,
};

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

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

      switch (scsi_debug_dif) {

      case SD_DIF_TYPE0_PROTECTION:
      case SD_DIF_TYPE1_PROTECTION:
      case SD_DIF_TYPE3_PROTECTION:
            break;

      default:
            printk(KERN_ERR "scsi_debug_init: dif must be 0, 1 or 3\n");
            return -EINVAL;
      }

      if (scsi_debug_guard > 1) {
            printk(KERN_ERR "scsi_debug_init: guard must be 0 or 1\n");
            return -EINVAL;
      }

      if (scsi_debug_ato > 1) {
            printk(KERN_ERR "scsi_debug_init: ato must be 0 or 1\n");
            return -EINVAL;
      }

      if (scsi_debug_physblk_exp > 15) {
            printk(KERN_ERR "scsi_debug_init: invalid physblk_exp %u\n",
                   scsi_debug_physblk_exp);
            return -EINVAL;
      }

      if (scsi_debug_lowest_aligned > 0x3fff) {
            printk(KERN_ERR "scsi_debug_init: lowest_aligned too big: %u\n",
                   scsi_debug_lowest_aligned);
            return -EINVAL;
      }

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

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

      fake_storep = vmalloc(sz);
      if (NULL == fake_storep) {
            printk(KERN_ERR "scsi_debug_init: out of memory, 1\n");
            return -ENOMEM;
      }
      memset(fake_storep, 0, sz);
      if (scsi_debug_num_parts > 0)
            sdebug_build_parts(fake_storep, sz);

      if (scsi_debug_dif) {
            int dif_size;

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

            printk(KERN_ERR "scsi_debug_init: dif_storep %u bytes @ %p\n",
                   dif_size, dif_storep);

            if (dif_storep == NULL) {
                  printk(KERN_ERR "scsi_debug_init: out of mem. (DIX)\n");
                  ret = -ENOMEM;
                  goto free_vm;
            }

            memset(dif_storep, 0xff, dif_size);
      }

      ret = device_register(&pseudo_primary);
      if (ret < 0) {
            printk(KERN_WARNING "scsi_debug: device_register error: %d\n",
                  ret);
            goto free_vm;
      }
      ret = bus_register(&pseudo_lld_bus);
      if (ret < 0) {
            printk(KERN_WARNING "scsi_debug: bus_register error: %d\n",
                  ret);
            goto dev_unreg;
      }
      ret = driver_register(&sdebug_driverfs_driver);
      if (ret < 0) {
            printk(KERN_WARNING "scsi_debug: driver_register error: %d\n",
                  ret);
            goto bus_unreg;
      }
      ret = do_create_driverfs_files();
      if (ret < 0) {
            printk(KERN_WARNING "scsi_debug: driver_create_file error: %d\n",
                  ret);
            goto del_files;
      }

      init_all_queued();

      host_to_add = scsi_debug_add_host;
        scsi_debug_add_host = 0;

        for (k = 0; k < host_to_add; k++) {
                if (sdebug_add_adapter()) {
                        printk(KERN_ERR "scsi_debug_init: "
                               "sdebug_add_adapter failed k=%d\n", k);
                        break;
                }
        }

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

del_files:
      do_remove_driverfs_files();
      driver_unregister(&sdebug_driverfs_driver);
bus_unreg:
      bus_unregister(&pseudo_lld_bus);
dev_unreg:
      device_unregister(&pseudo_primary);
free_vm:
      if (dif_storep)
            vfree(dif_storep);
      vfree(fake_storep);

      return ret;
}

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

      stop_all_queued();
      for (; k; k--)
            sdebug_remove_adapter();
      do_remove_driverfs_files();
      driver_unregister(&sdebug_driverfs_driver);
      bus_unregister(&pseudo_lld_bus);
      device_unregister(&pseudo_primary);

      if (dif_storep)
            vfree(dif_storep);

      vfree(fake_storep);
}

device_initcall(scsi_debug_init);
module_exit(scsi_debug_exit);

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

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

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

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

        INIT_LIST_HEAD(&sdbg_host->dev_info_list);

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

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

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

        error = device_register(&sdbg_host->dev);

        if (error)
            goto clean;

      ++scsi_debug_add_host;
        return error;

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

      kfree(sdbg_host);
        return error;
}

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

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

      if (!sdbg_host)
            return;

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

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

      scsi_set_resid(SCpnt, 0);
      if ((SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) && cmd) {
            printk(KERN_INFO "scsi_debug: cmd ");
            for (k = 0, len = SCpnt->cmd_len; k < len; ++k)
                  printk("%02x ", (int)cmd[k]);
            printk("\n");
      }

      if (target == SCpnt->device->host->hostt->this_id) {
            printk(KERN_INFO "scsi_debug: initiator's id used as "
                   "target!\n");
            return schedule_resp(SCpnt, NULL, done,
                             DID_NO_CONNECT << 16, 0);
      }

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

      if ((scsi_debug_every_nth != 0) &&
          (++scsi_debug_cmnd_count >= abs(scsi_debug_every_nth))) {
            scsi_debug_cmnd_count = 0;
            if (scsi_debug_every_nth < -1)
                  scsi_debug_every_nth = -1;
            if (SCSI_DEBUG_OPT_TIMEOUT & scsi_debug_opts)
                  return 0; /* ignore command causing timeout */
            else if (SCSI_DEBUG_OPT_RECOVERED_ERR & scsi_debug_opts)
                  inj_recovered = 1; /* to reads and writes below */
            else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & scsi_debug_opts)
                  inj_transport = 1; /* to reads and writes below */
            else if (SCSI_DEBUG_OPT_DIF_ERR & scsi_debug_opts)
                  inj_dif = 1; /* to reads and writes below */
            else if (SCSI_DEBUG_OPT_DIX_ERR & scsi_debug_opts)
                  inj_dix = 1; /* to reads and writes below */
      }

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

      switch (*cmd) {
      case INQUIRY:     /* mandatory, ignore unit attention */
            delay_override = 1;
            errsts = resp_inquiry(SCpnt, target, devip);
            break;
      case REQUEST_SENSE:     /* mandatory, ignore unit attention */
            delay_override = 1;
            errsts = resp_requests(SCpnt, devip);
            break;
      case REZERO_UNIT: /* actually this is REWIND for SSC */
      case START_STOP:
            errsts = resp_start_stop(SCpnt, devip);
            break;
      case ALLOW_MEDIUM_REMOVAL:
            errsts = check_readiness(SCpnt, 1, devip);
            if (errsts)
                  break;
            if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
                  printk(KERN_INFO "scsi_debug: Medium removal %s\n",
                         cmd[4] ? "inhibited" : "enabled");
            break;
      case SEND_DIAGNOSTIC:     /* mandatory */
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case TEST_UNIT_READY:     /* mandatory */
            delay_override = 1;
            errsts = check_readiness(SCpnt, 0, devip);
            break;
      case RESERVE:
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case RESERVE_10:
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case RELEASE:
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case RELEASE_10:
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case READ_CAPACITY:
            errsts = resp_readcap(SCpnt, devip);
            break;
      case SERVICE_ACTION_IN:
            if (SAI_READ_CAPACITY_16 != cmd[1]) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST,
                              INVALID_OPCODE, 0);
                  errsts = check_condition_result;
                  break;
            }
            errsts = resp_readcap16(SCpnt, devip);
            break;
      case MAINTENANCE_IN:
            if (MI_REPORT_TARGET_PGS != cmd[1]) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST,
                              INVALID_OPCODE, 0);
                  errsts = check_condition_result;
                  break;
            }
            errsts = resp_report_tgtpgs(SCpnt, devip);
            break;
      case READ_16:
      case READ_12:
      case READ_10:
      case READ_6:
            errsts = check_readiness(SCpnt, 0, devip);
            if (errsts)
                  break;
            if (scsi_debug_fake_rw)
                  break;
            get_data_transfer_info(cmd, &lba, &num);
            errsts = resp_read(SCpnt, lba, num, devip);
            if (inj_recovered && (0 == errsts)) {
                  mk_sense_buffer(devip, RECOVERED_ERROR,
                              THRESHOLD_EXCEEDED, 0);
                  errsts = check_condition_result;
            } else if (inj_transport && (0 == errsts)) {
                  mk_sense_buffer(devip, ABORTED_COMMAND,
                              TRANSPORT_PROBLEM, ACK_NAK_TO);
                  errsts = check_condition_result;
            } else if (inj_dif && (0 == errsts)) {
                  mk_sense_buffer(devip, ABORTED_COMMAND, 0x10, 1);
                  errsts = illegal_condition_result;
            } else if (inj_dix && (0 == errsts)) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST, 0x10, 1);
                  errsts = illegal_condition_result;
            }
            break;
      case REPORT_LUNS: /* mandatory, ignore unit attention */
            delay_override = 1;
            errsts = resp_report_luns(SCpnt, devip);
            break;
      case VERIFY:            /* 10 byte SBC-2 command */
            errsts = check_readiness(SCpnt, 0, devip);
            break;
      case WRITE_16:
      case WRITE_12:
      case WRITE_10:
      case WRITE_6:
            errsts = check_readiness(SCpnt, 0, devip);
            if (errsts)
                  break;
            if (scsi_debug_fake_rw)
                  break;
            get_data_transfer_info(cmd, &lba, &num);
            errsts = resp_write(SCpnt, lba, num, devip);
            if (inj_recovered && (0 == errsts)) {
                  mk_sense_buffer(devip, RECOVERED_ERROR,
                              THRESHOLD_EXCEEDED, 0);
                  errsts = check_condition_result;
            } else if (inj_dif && (0 == errsts)) {
                  mk_sense_buffer(devip, ABORTED_COMMAND, 0x10, 1);
                  errsts = illegal_condition_result;
            } else if (inj_dix && (0 == errsts)) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST, 0x10, 1);
                  errsts = illegal_condition_result;
            }
            break;
      case MODE_SENSE:
      case MODE_SENSE_10:
            errsts = resp_mode_sense(SCpnt, target, devip);
            break;
      case MODE_SELECT:
            errsts = resp_mode_select(SCpnt, 1, devip);
            break;
      case MODE_SELECT_10:
            errsts = resp_mode_select(SCpnt, 0, devip);
            break;
      case LOG_SENSE:
            errsts = resp_log_sense(SCpnt, devip);
            break;
      case SYNCHRONIZE_CACHE:
            delay_override = 1;
            errsts = check_readiness(SCpnt, 0, devip);
            break;
      case WRITE_BUFFER:
            errsts = check_readiness(SCpnt, 1, devip);
            break;
      case XDWRITEREAD_10:
            if (!scsi_bidi_cmnd(SCpnt)) {
                  mk_sense_buffer(devip, ILLEGAL_REQUEST,
                              INVALID_FIELD_IN_CDB, 0);
                  errsts = check_condition_result;
                  break;
            }

            errsts = check_readiness(SCpnt, 0, devip);
            if (errsts)
                  break;
            if (scsi_debug_fake_rw)
                  break;
            get_data_transfer_info(cmd, &lba, &num);
            errsts = resp_read(SCpnt, lba, num, devip);
            if (errsts)
                  break;
            errsts = resp_write(SCpnt, lba, num, devip);
            if (errsts)
                  break;
            errsts = resp_xdwriteread(SCpnt, lba, num, devip);
            break;
      default:
            if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
                  printk(KERN_INFO "scsi_debug: Opcode: 0x%x not "
                         "supported\n", *cmd);
            errsts = check_readiness(SCpnt, 1, devip);
            if (errsts)
                  break;      /* Unit attention takes precedence */
            mk_sense_buffer(devip, ILLEGAL_REQUEST, INVALID_OPCODE, 0);
            errsts = check_condition_result;
            break;
      }
      return schedule_resp(SCpnt, devip, done, errsts,
                       (delay_override ? 0 : scsi_debug_delay));
}

static struct scsi_host_template sdebug_driver_template = {
      .proc_info =            scsi_debug_proc_info,
      .proc_name =            sdebug_proc_name,
      .name =                 "SCSI DEBUG",
      .info =                 scsi_debug_info,
      .slave_alloc =          scsi_debug_slave_alloc,
      .slave_configure =      scsi_debug_slave_configure,
      .slave_destroy =  scsi_debug_slave_destroy,
      .ioctl =          scsi_debug_ioctl,
      .queuecommand =         scsi_debug_queuecommand,
      .eh_abort_handler =     scsi_debug_abort,
      .eh_bus_reset_handler = scsi_debug_bus_reset,
      .eh_device_reset_handler = scsi_debug_device_reset,
      .eh_host_reset_handler = scsi_debug_host_reset,
      .bios_param =           scsi_debug_biosparam,
      .can_queue =            SCSI_DEBUG_CANQUEUE,
      .this_id =        7,
      .sg_tablesize =         256,
      .cmd_per_lun =          16,
      .max_sectors =          0xffff,
      .use_clustering =       DISABLE_CLUSTERING,
      .module =         THIS_MODULE,
};

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

      sdbg_host = to_sdebug_host(dev);

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

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

      host_prot = 0;

      switch (scsi_debug_dif) {

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

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

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

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

      scsi_host_set_prot(hpnt, host_prot);

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

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

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


        return error;
}

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

      sdbg_host = to_sdebug_host(dev);

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

        scsi_remove_host(sdbg_host->shost);

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

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

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

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

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