target_core_pscsi.c

Go to the documentation of this file.

/*******************************************************************************
 * Filename:  target_core_pscsi.c
 *
 * This file contains the generic target mode <-> Linux SCSI subsystem plugin.
 *
 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
 * Copyright (c) 2007-2010 Rising Tide Systems
 * Copyright (c) 2008-2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/string.h>
#include <linux/parser.h>
#include <linux/timer.h>
#include <linux/blkdev.h>
#include <linux/blk_types.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/genhd.h>
#include <linux/cdrom.h>
#include <linux/ratelimit.h>
#include <linux/module.h>
#include <asm/unaligned.h>

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

#include <target/target_core_base.h>
#include <target/target_core_backend.h>

#include "target_core_alua.h"
#include "target_core_pscsi.h"

#define ISPRINT(a)  ((a >= ' ') && (a <= '~'))

static struct se_subsystem_api pscsi_template;

static int pscsi_execute_cmd(struct se_cmd *cmd);
static void pscsi_req_done(struct request *, int);

/*  pscsi_attach_hba():
 *
 *  pscsi_get_sh() used scsi_host_lookup() to locate struct Scsi_Host.
 *  from the passed SCSI Host ID.
 */
static int pscsi_attach_hba(struct se_hba *hba, u32 host_id)
{
    struct pscsi_hba_virt *phv;

    phv = kzalloc(sizeof(struct pscsi_hba_virt), GFP_KERNEL);
    if (!phv) {
        pr_err("Unable to allocate struct pscsi_hba_virt\n");
        return -ENOMEM;
    }
    phv->phv_host_id = host_id;
    phv->phv_mode = PHV_VIRTUAL_HOST_ID;

    hba->hba_ptr = phv;

    pr_debug("CORE_HBA[%d] - TCM SCSI HBA Driver %s on"
        " Generic Target Core Stack %s\n", hba->hba_id,
        PSCSI_VERSION, TARGET_CORE_MOD_VERSION);
    pr_debug("CORE_HBA[%d] - Attached SCSI HBA to Generic\n",
           hba->hba_id);

    return 0;
}

static void pscsi_detach_hba(struct se_hba *hba)
{
    struct pscsi_hba_virt *phv = hba->hba_ptr;
    struct Scsi_Host *scsi_host = phv->phv_lld_host;

    if (scsi_host) {
        scsi_host_put(scsi_host);

        pr_debug("CORE_HBA[%d] - Detached SCSI HBA: %s from"
            " Generic Target Core\n", hba->hba_id,
            (scsi_host->hostt->name) ? (scsi_host->hostt->name) :
            "Unknown");
    } else
        pr_debug("CORE_HBA[%d] - Detached Virtual SCSI HBA"
            " from Generic Target Core\n", hba->hba_id);

    kfree(phv);
    hba->hba_ptr = NULL;
}

static int pscsi_pmode_enable_hba(struct se_hba *hba, unsigned long mode_flag)
{
    struct pscsi_hba_virt *phv = hba->hba_ptr;
    struct Scsi_Host *sh = phv->phv_lld_host;
    /*
     * Release the struct Scsi_Host
     */
    if (!mode_flag) {
        if (!sh)
            return 0;

        phv->phv_lld_host = NULL;
        phv->phv_mode = PHV_VIRTUAL_HOST_ID;

        pr_debug("CORE_HBA[%d] - Disabled pSCSI HBA Passthrough"
            " %s\n", hba->hba_id, (sh->hostt->name) ?
            (sh->hostt->name) : "Unknown");

        scsi_host_put(sh);
        return 0;
    }
    /*
     * Otherwise, locate struct Scsi_Host from the original passed
     * pSCSI Host ID and enable for phba mode
     */
    sh = scsi_host_lookup(phv->phv_host_id);
    if (IS_ERR(sh)) {
        pr_err("pSCSI: Unable to locate SCSI Host for"
            " phv_host_id: %d\n", phv->phv_host_id);
        return PTR_ERR(sh);
    }

    phv->phv_lld_host = sh;
    phv->phv_mode = PHV_LLD_SCSI_HOST_NO;

    pr_debug("CORE_HBA[%d] - Enabled pSCSI HBA Passthrough %s\n",
        hba->hba_id, (sh->hostt->name) ? (sh->hostt->name) : "Unknown");

    return 1;
}

static void pscsi_tape_read_blocksize(struct se_device *dev,
        struct scsi_device *sdev)
{
    unsigned char cdb[MAX_COMMAND_SIZE], *buf;
    int ret;

    buf = kzalloc(12, GFP_KERNEL);
    if (!buf)
        return;

    memset(cdb, 0, MAX_COMMAND_SIZE);
    cdb[0] = MODE_SENSE;
    cdb[4] = 0x0c; /* 12 bytes */

    ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf, 12, NULL,
            HZ, 1, NULL);
    if (ret)
        goto out_free;

    /*
     * If MODE_SENSE still returns zero, set the default value to 1024.
     */
    sdev->sector_size = (buf[9] << 16) | (buf[10] << 8) | (buf[11]);
    if (!sdev->sector_size)
        sdev->sector_size = 1024;
out_free:
    kfree(buf);
}

static void
pscsi_set_inquiry_info(struct scsi_device *sdev, struct t10_wwn *wwn)
{
    unsigned char *buf;

    if (sdev->inquiry_len < INQUIRY_LEN)
        return;

    buf = sdev->inquiry;
    if (!buf)
        return;
    /*
     * Use sdev->inquiry from drivers/scsi/scsi_scan.c:scsi_alloc_sdev()
     */
    memcpy(&wwn->vendor[0], &buf[8], sizeof(wwn->vendor));
    memcpy(&wwn->model[0], &buf[16], sizeof(wwn->model));
    memcpy(&wwn->revision[0], &buf[32], sizeof(wwn->revision));
}

static int
pscsi_get_inquiry_vpd_serial(struct scsi_device *sdev, struct t10_wwn *wwn)
{
    unsigned char cdb[MAX_COMMAND_SIZE], *buf;
    int ret;

    buf = kzalloc(INQUIRY_VPD_SERIAL_LEN, GFP_KERNEL);
    if (!buf)
        return -ENOMEM;

    memset(cdb, 0, MAX_COMMAND_SIZE);
    cdb[0] = INQUIRY;
    cdb[1] = 0x01; /* Query VPD */
    cdb[2] = 0x80; /* Unit Serial Number */
    cdb[3] = (INQUIRY_VPD_SERIAL_LEN >> 8) & 0xff;
    cdb[4] = (INQUIRY_VPD_SERIAL_LEN & 0xff);

    ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf,
                  INQUIRY_VPD_SERIAL_LEN, NULL, HZ, 1, NULL);
    if (ret)
        goto out_free;

    snprintf(&wwn->unit_serial[0], INQUIRY_VPD_SERIAL_LEN, "%s", &buf[4]);

    wwn->t10_sub_dev->su_dev_flags |= SDF_FIRMWARE_VPD_UNIT_SERIAL;

    kfree(buf);
    return 0;

out_free:
    kfree(buf);
    return -EPERM;
}

static void
pscsi_get_inquiry_vpd_device_ident(struct scsi_device *sdev,
        struct t10_wwn *wwn)
{
    unsigned char cdb[MAX_COMMAND_SIZE], *buf, *page_83;
    int ident_len, page_len, off = 4, ret;
    struct t10_vpd *vpd;

    buf = kzalloc(INQUIRY_VPD_SERIAL_LEN, GFP_KERNEL);
    if (!buf)
        return;

    memset(cdb, 0, MAX_COMMAND_SIZE);
    cdb[0] = INQUIRY;
    cdb[1] = 0x01; /* Query VPD */
    cdb[2] = 0x83; /* Device Identifier */
    cdb[3] = (INQUIRY_VPD_DEVICE_IDENTIFIER_LEN >> 8) & 0xff;
    cdb[4] = (INQUIRY_VPD_DEVICE_IDENTIFIER_LEN & 0xff);

    ret = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE, buf,
                  INQUIRY_VPD_DEVICE_IDENTIFIER_LEN,
                  NULL, HZ, 1, NULL);
    if (ret)
        goto out;

    page_len = (buf[2] << 8) | buf[3];
    while (page_len > 0) {
        /* Grab a pointer to the Identification descriptor */
        page_83 = &buf[off];
        ident_len = page_83[3];
        if (!ident_len) {
            pr_err("page_83[3]: identifier"
                    " length zero!\n");
            break;
        }
        pr_debug("T10 VPD Identifier Length: %d\n", ident_len);

        vpd = kzalloc(sizeof(struct t10_vpd), GFP_KERNEL);
        if (!vpd) {
            pr_err("Unable to allocate memory for"
                    " struct t10_vpd\n");
            goto out;
        }
        INIT_LIST_HEAD(&vpd->vpd_list);

        transport_set_vpd_proto_id(vpd, page_83);
        transport_set_vpd_assoc(vpd, page_83);

        if (transport_set_vpd_ident_type(vpd, page_83) < 0) {
            off += (ident_len + 4);
            page_len -= (ident_len + 4);
            kfree(vpd);
            continue;
        }
        if (transport_set_vpd_ident(vpd, page_83) < 0) {
            off += (ident_len + 4);
            page_len -= (ident_len + 4);
            kfree(vpd);
            continue;
        }

        list_add_tail(&vpd->vpd_list, &wwn->t10_vpd_list);
        off += (ident_len + 4);
        page_len -= (ident_len + 4);
    }

out:
    kfree(buf);
}

/*  pscsi_add_device_to_list():
 *
 *
 */
static struct se_device *pscsi_add_device_to_list(
    struct se_hba *hba,
    struct se_subsystem_dev *se_dev,
    struct pscsi_dev_virt *pdv,
    struct scsi_device *sd,
    int dev_flags)
{
    struct se_device *dev;
    struct se_dev_limits dev_limits;
    struct request_queue *q;
    struct queue_limits *limits;

    memset(&dev_limits, 0, sizeof(struct se_dev_limits));

    if (!sd->queue_depth) {
        sd->queue_depth = PSCSI_DEFAULT_QUEUEDEPTH;

        pr_err("Set broken SCSI Device %d:%d:%d"
            " queue_depth to %d\n", sd->channel, sd->id,
                sd->lun, sd->queue_depth);
    }
    /*
     * Setup the local scope queue_limits from struct request_queue->limits
     * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
     */
    q = sd->request_queue;
    limits = &dev_limits.limits;
    limits->logical_block_size = sd->sector_size;
    limits->max_hw_sectors = min_t(int, sd->host->max_sectors, queue_max_hw_sectors(q));
    limits->max_sectors = min_t(int, sd->host->max_sectors, queue_max_sectors(q));
    dev_limits.hw_queue_depth = sd->queue_depth;
    dev_limits.queue_depth = sd->queue_depth;
    /*
     * Setup our standard INQUIRY info into se_dev->t10_wwn
     */
    pscsi_set_inquiry_info(sd, &se_dev->t10_wwn);

    /*
     * Set the pointer pdv->pdv_sd to from passed struct scsi_device,
     * which has already been referenced with Linux SCSI code with
     * scsi_device_get() in this file's pscsi_create_virtdevice().
     *
     * The passthrough operations called by the transport_add_device_*
     * function below will require this pointer to be set for passthroug
     *  ops.
     *
     * For the shutdown case in pscsi_free_device(), this struct
     * scsi_device  reference is released with Linux SCSI code
     * scsi_device_put() and the pdv->pdv_sd cleared.
     */
    pdv->pdv_sd = sd;
    dev = transport_add_device_to_core_hba(hba, &pscsi_template,
                se_dev, dev_flags, pdv,
                &dev_limits, NULL, NULL);
    if (!dev) {
        pdv->pdv_sd = NULL;
        return NULL;
    }

    /*
     * Locate VPD WWN Information used for various purposes within
     * the Storage Engine.
     */
    if (!pscsi_get_inquiry_vpd_serial(sd, &se_dev->t10_wwn)) {
        /*
         * If VPD Unit Serial returned GOOD status, try
         * VPD Device Identification page (0x83).
         */
        pscsi_get_inquiry_vpd_device_ident(sd, &se_dev->t10_wwn);
    }

    /*
     * For TYPE_TAPE, attempt to determine blocksize with MODE_SENSE.
     */
    if (sd->type == TYPE_TAPE)
        pscsi_tape_read_blocksize(dev, sd);
    return dev;
}

static void *pscsi_allocate_virtdevice(struct se_hba *hba, const char *name)
{
    struct pscsi_dev_virt *pdv;

    pdv = kzalloc(sizeof(struct pscsi_dev_virt), GFP_KERNEL);
    if (!pdv) {
        pr_err("Unable to allocate memory for struct pscsi_dev_virt\n");
        return NULL;
    }
    pdv->pdv_se_hba = hba;

    pr_debug("PSCSI: Allocated pdv: %p for %s\n", pdv, name);
    return pdv;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static struct se_device *pscsi_create_type_disk(
    struct scsi_device *sd,
    struct pscsi_dev_virt *pdv,
    struct se_subsystem_dev *se_dev,
    struct se_hba *hba)
    __releases(sh->host_lock)
{
    struct se_device *dev;
    struct pscsi_hba_virt *phv = pdv->pdv_se_hba->hba_ptr;
    struct Scsi_Host *sh = sd->host;
    struct block_device *bd;
    u32 dev_flags = 0;

    if (scsi_device_get(sd)) {
        pr_err("scsi_device_get() failed for %d:%d:%d:%d\n",
            sh->host_no, sd->channel, sd->id, sd->lun);
        spin_unlock_irq(sh->host_lock);
        return NULL;
    }
    spin_unlock_irq(sh->host_lock);
    /*
     * Claim exclusive struct block_device access to struct scsi_device
     * for TYPE_DISK using supplied udev_path
     */
    bd = blkdev_get_by_path(se_dev->se_dev_udev_path,
                FMODE_WRITE|FMODE_READ|FMODE_EXCL, pdv);
    if (IS_ERR(bd)) {
        pr_err("pSCSI: blkdev_get_by_path() failed\n");
        scsi_device_put(sd);
        return NULL;
    }
    pdv->pdv_bd = bd;

    dev = pscsi_add_device_to_list(hba, se_dev, pdv, sd, dev_flags);
    if (!dev) {
        blkdev_put(pdv->pdv_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
        scsi_device_put(sd);
        return NULL;
    }
    pr_debug("CORE_PSCSI[%d] - Added TYPE_DISK for %d:%d:%d:%d\n",
        phv->phv_host_id, sh->host_no, sd->channel, sd->id, sd->lun);

    return dev;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static struct se_device *pscsi_create_type_rom(
    struct scsi_device *sd,
    struct pscsi_dev_virt *pdv,
    struct se_subsystem_dev *se_dev,
    struct se_hba *hba)
    __releases(sh->host_lock)
{
    struct se_device *dev;
    struct pscsi_hba_virt *phv = pdv->pdv_se_hba->hba_ptr;
    struct Scsi_Host *sh = sd->host;
    u32 dev_flags = 0;

    if (scsi_device_get(sd)) {
        pr_err("scsi_device_get() failed for %d:%d:%d:%d\n",
            sh->host_no, sd->channel, sd->id, sd->lun);
        spin_unlock_irq(sh->host_lock);
        return NULL;
    }
    spin_unlock_irq(sh->host_lock);

    dev = pscsi_add_device_to_list(hba, se_dev, pdv, sd, dev_flags);
    if (!dev) {
        scsi_device_put(sd);
        return NULL;
    }
    pr_debug("CORE_PSCSI[%d] - Added Type: %s for %d:%d:%d:%d\n",
        phv->phv_host_id, scsi_device_type(sd->type), sh->host_no,
        sd->channel, sd->id, sd->lun);

    return dev;
}

/*
 *Called with struct Scsi_Host->host_lock called.
 */
static struct se_device *pscsi_create_type_other(
    struct scsi_device *sd,
    struct pscsi_dev_virt *pdv,
    struct se_subsystem_dev *se_dev,
    struct se_hba *hba)
    __releases(sh->host_lock)
{
    struct se_device *dev;
    struct pscsi_hba_virt *phv = pdv->pdv_se_hba->hba_ptr;
    struct Scsi_Host *sh = sd->host;
    u32 dev_flags = 0;

    spin_unlock_irq(sh->host_lock);
    dev = pscsi_add_device_to_list(hba, se_dev, pdv, sd, dev_flags);
    if (!dev)
        return NULL;

    pr_debug("CORE_PSCSI[%d] - Added Type: %s for %d:%d:%d:%d\n",
        phv->phv_host_id, scsi_device_type(sd->type), sh->host_no,
        sd->channel, sd->id, sd->lun);

    return dev;
}

static struct se_device *pscsi_create_virtdevice(
    struct se_hba *hba,
    struct se_subsystem_dev *se_dev,
    void *p)
{
    struct pscsi_dev_virt *pdv = p;
    struct se_device *dev;
    struct scsi_device *sd;
    struct pscsi_hba_virt *phv = hba->hba_ptr;
    struct Scsi_Host *sh = phv->phv_lld_host;
    int legacy_mode_enable = 0;

    if (!pdv) {
        pr_err("Unable to locate struct pscsi_dev_virt"
                " parameter\n");
        return ERR_PTR(-EINVAL);
    }
    /*
     * If not running in PHV_LLD_SCSI_HOST_NO mode, locate the
     * struct Scsi_Host we will need to bring the TCM/pSCSI object online
     */
    if (!sh) {
        if (phv->phv_mode == PHV_LLD_SCSI_HOST_NO) {
            pr_err("pSCSI: Unable to locate struct"
                " Scsi_Host for PHV_LLD_SCSI_HOST_NO\n");
            return ERR_PTR(-ENODEV);
        }
        /*
         * For the newer PHV_VIRTUAL_HOST_ID struct scsi_device
         * reference, we enforce that udev_path has been set
         */
        if (!(se_dev->su_dev_flags & SDF_USING_UDEV_PATH)) {
            pr_err("pSCSI: udev_path attribute has not"
                " been set before ENABLE=1\n");
            return ERR_PTR(-EINVAL);
        }
        /*
         * If no scsi_host_id= was passed for PHV_VIRTUAL_HOST_ID,
         * use the original TCM hba ID to reference Linux/SCSI Host No
         * and enable for PHV_LLD_SCSI_HOST_NO mode.
         */
        if (!(pdv->pdv_flags & PDF_HAS_VIRT_HOST_ID)) {
            spin_lock(&hba->device_lock);
            if (!list_empty(&hba->hba_dev_list)) {
                pr_err("pSCSI: Unable to set hba_mode"
                    " with active devices\n");
                spin_unlock(&hba->device_lock);
                return ERR_PTR(-EEXIST);
            }
            spin_unlock(&hba->device_lock);

            if (pscsi_pmode_enable_hba(hba, 1) != 1)
                return ERR_PTR(-ENODEV);

            legacy_mode_enable = 1;
            hba->hba_flags |= HBA_FLAGS_PSCSI_MODE;
            sh = phv->phv_lld_host;
        } else {
            sh = scsi_host_lookup(pdv->pdv_host_id);
            if (IS_ERR(sh)) {
                pr_err("pSCSI: Unable to locate"
                    " pdv_host_id: %d\n", pdv->pdv_host_id);
                return ERR_CAST(sh);
            }
        }
    } else {
        if (phv->phv_mode == PHV_VIRTUAL_HOST_ID) {
            pr_err("pSCSI: PHV_VIRTUAL_HOST_ID set while"
                " struct Scsi_Host exists\n");
            return ERR_PTR(-EEXIST);
        }
    }

    spin_lock_irq(sh->host_lock);
    list_for_each_entry(sd, &sh->__devices, siblings) {
        if ((pdv->pdv_channel_id != sd->channel) ||
            (pdv->pdv_target_id != sd->id) ||
            (pdv->pdv_lun_id != sd->lun))
            continue;
        /*
         * Functions will release the held struct scsi_host->host_lock
         * before calling calling pscsi_add_device_to_list() to register
         * struct scsi_device with target_core_mod.
         */
        switch (sd->type) {
        case TYPE_DISK:
            dev = pscsi_create_type_disk(sd, pdv, se_dev, hba);
            break;
        case TYPE_ROM:
            dev = pscsi_create_type_rom(sd, pdv, se_dev, hba);
            break;
        default:
            dev = pscsi_create_type_other(sd, pdv, se_dev, hba);
            break;
        }

        if (!dev) {
            if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
                scsi_host_put(sh);
            else if (legacy_mode_enable) {
                pscsi_pmode_enable_hba(hba, 0);
                hba->hba_flags &= ~HBA_FLAGS_PSCSI_MODE;
            }
            pdv->pdv_sd = NULL;
            return ERR_PTR(-ENODEV);
        }
        return dev;
    }
    spin_unlock_irq(sh->host_lock);

    pr_err("pSCSI: Unable to locate %d:%d:%d:%d\n", sh->host_no,
        pdv->pdv_channel_id,  pdv->pdv_target_id, pdv->pdv_lun_id);

    if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
        scsi_host_put(sh);
    else if (legacy_mode_enable) {
        pscsi_pmode_enable_hba(hba, 0);
        hba->hba_flags &= ~HBA_FLAGS_PSCSI_MODE;
    }

    return ERR_PTR(-ENODEV);
}

/*  pscsi_free_device(): (Part of se_subsystem_api_t template)
 *
 *
 */
static void pscsi_free_device(void *p)
{
    struct pscsi_dev_virt *pdv = p;
    struct pscsi_hba_virt *phv = pdv->pdv_se_hba->hba_ptr;
    struct scsi_device *sd = pdv->pdv_sd;

    if (sd) {
        /*
         * Release exclusive pSCSI internal struct block_device claim for
         * struct scsi_device with TYPE_DISK from pscsi_create_type_disk()
         */
        if ((sd->type == TYPE_DISK) && pdv->pdv_bd) {
            blkdev_put(pdv->pdv_bd,
                   FMODE_WRITE|FMODE_READ|FMODE_EXCL);
            pdv->pdv_bd = NULL;
        }
        /*
         * For HBA mode PHV_LLD_SCSI_HOST_NO, release the reference
         * to struct Scsi_Host now.
         */
        if ((phv->phv_mode == PHV_LLD_SCSI_HOST_NO) &&
            (phv->phv_lld_host != NULL))
            scsi_host_put(phv->phv_lld_host);

        if ((sd->type == TYPE_DISK) || (sd->type == TYPE_ROM))
            scsi_device_put(sd);

        pdv->pdv_sd = NULL;
    }

    kfree(pdv);
}

static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,
                     unsigned char *sense_buffer)
{
    struct pscsi_dev_virt *pdv = cmd->se_dev->dev_ptr;
    struct scsi_device *sd = pdv->pdv_sd;
    int result;
    struct pscsi_plugin_task *pt = cmd->priv;
    unsigned char *cdb;
    /*
     * Special case for REPORT_LUNs handling where pscsi_plugin_task has
     * not been allocated because TCM is handling the emulation directly.
     */
    if (!pt)
        return;

    cdb = &pt->pscsi_cdb[0];
    result = pt->pscsi_result;
    /*
     * Hack to make sure that Write-Protect modepage is set if R/O mode is
     * forced.
     */
    if (!cmd->se_deve || !cmd->data_length)
        goto after_mode_sense;

    if (((cdb[0] == MODE_SENSE) || (cdb[0] == MODE_SENSE_10)) &&
         (status_byte(result) << 1) == SAM_STAT_GOOD) {
        if (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY) {
            unsigned char *buf = transport_kmap_data_sg(cmd);

            if (cdb[0] == MODE_SENSE_10) {
                if (!(buf[3] & 0x80))
                    buf[3] |= 0x80;
            } else {
                if (!(buf[2] & 0x80))
                    buf[2] |= 0x80;
            }

            transport_kunmap_data_sg(cmd);
        }
    }
after_mode_sense:

    if (sd->type != TYPE_TAPE || !cmd->data_length)
        goto after_mode_select;

    /*
     * Hack to correctly obtain the initiator requested blocksize for
     * TYPE_TAPE.  Since this value is dependent upon each tape media,
     * struct scsi_device->sector_size will not contain the correct value
     * by default, so we go ahead and set it so
     * TRANSPORT(dev)->get_blockdev() returns the correct value to the
     * storage engine.
     */
    if (((cdb[0] == MODE_SELECT) || (cdb[0] == MODE_SELECT_10)) &&
          (status_byte(result) << 1) == SAM_STAT_GOOD) {
        unsigned char *buf;
        u16 bdl;
        u32 blocksize;

        buf = sg_virt(&sg[0]);
        if (!buf) {
            pr_err("Unable to get buf for scatterlist\n");
            goto after_mode_select;
        }

        if (cdb[0] == MODE_SELECT)
            bdl = (buf[3]);
        else
            bdl = (buf[6] << 8) | (buf[7]);

        if (!bdl)
            goto after_mode_select;

        if (cdb[0] == MODE_SELECT)
            blocksize = (buf[9] << 16) | (buf[10] << 8) |
                    (buf[11]);
        else
            blocksize = (buf[13] << 16) | (buf[14] << 8) |
                    (buf[15]);

        sd->sector_size = blocksize;
    }
after_mode_select:

    if (sense_buffer && (status_byte(result) & CHECK_CONDITION)) {
        memcpy(sense_buffer, pt->pscsi_sense, TRANSPORT_SENSE_BUFFER);
        cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
    }
}

enum {
    Opt_scsi_host_id, Opt_scsi_channel_id, Opt_scsi_target_id,
    Opt_scsi_lun_id, Opt_err
};

static match_table_t tokens = {
    {Opt_scsi_host_id, "scsi_host_id=%d"},
    {Opt_scsi_channel_id, "scsi_channel_id=%d"},
    {Opt_scsi_target_id, "scsi_target_id=%d"},
    {Opt_scsi_lun_id, "scsi_lun_id=%d"},
    {Opt_err, NULL}
};

static ssize_t pscsi_set_configfs_dev_params(struct se_hba *hba,
    struct se_subsystem_dev *se_dev,
    const char *page,
    ssize_t count)
{
    struct pscsi_dev_virt *pdv = se_dev->se_dev_su_ptr;
    struct pscsi_hba_virt *phv = hba->hba_ptr;
    char *orig, *ptr, *opts;
    substring_t args[MAX_OPT_ARGS];
    int ret = 0, arg, token;

    opts = kstrdup(page, GFP_KERNEL);
    if (!opts)
        return -ENOMEM;

    orig = opts;

    while ((ptr = strsep(&opts, ",\n")) != NULL) {
        if (!*ptr)
            continue;

        token = match_token(ptr, tokens, args);
        switch (token) {
        case Opt_scsi_host_id:
            if (phv->phv_mode == PHV_LLD_SCSI_HOST_NO) {
                pr_err("PSCSI[%d]: Unable to accept"
                    " scsi_host_id while phv_mode =="
                    " PHV_LLD_SCSI_HOST_NO\n",
                    phv->phv_host_id);
                ret = -EINVAL;
                goto out;
            }
            match_int(args, &arg);
            pdv->pdv_host_id = arg;
            pr_debug("PSCSI[%d]: Referencing SCSI Host ID:"
                " %d\n", phv->phv_host_id, pdv->pdv_host_id);
            pdv->pdv_flags |= PDF_HAS_VIRT_HOST_ID;
            break;
        case Opt_scsi_channel_id:
            match_int(args, &arg);
            pdv->pdv_channel_id = arg;
            pr_debug("PSCSI[%d]: Referencing SCSI Channel"
                " ID: %d\n",  phv->phv_host_id,
                pdv->pdv_channel_id);
            pdv->pdv_flags |= PDF_HAS_CHANNEL_ID;
            break;
        case Opt_scsi_target_id:
            match_int(args, &arg);
            pdv->pdv_target_id = arg;
            pr_debug("PSCSI[%d]: Referencing SCSI Target"
                " ID: %d\n", phv->phv_host_id,
                pdv->pdv_target_id);
            pdv->pdv_flags |= PDF_HAS_TARGET_ID;
            break;
        case Opt_scsi_lun_id:
            match_int(args, &arg);
            pdv->pdv_lun_id = arg;
            pr_debug("PSCSI[%d]: Referencing SCSI LUN ID:"
                " %d\n", phv->phv_host_id, pdv->pdv_lun_id);
            pdv->pdv_flags |= PDF_HAS_LUN_ID;
            break;
        default:
            break;
        }
    }

out:
    kfree(orig);
    return (!ret) ? count : ret;
}

static ssize_t pscsi_check_configfs_dev_params(
    struct se_hba *hba,
    struct se_subsystem_dev *se_dev)
{
    struct pscsi_dev_virt *pdv = se_dev->se_dev_su_ptr;

    if (!(pdv->pdv_flags & PDF_HAS_CHANNEL_ID) ||
        !(pdv->pdv_flags & PDF_HAS_TARGET_ID) ||
        !(pdv->pdv_flags & PDF_HAS_LUN_ID)) {
        pr_err("Missing scsi_channel_id=, scsi_target_id= and"
            " scsi_lun_id= parameters\n");
        return -EINVAL;
    }

    return 0;
}

static ssize_t pscsi_show_configfs_dev_params(struct se_hba *hba,
                          struct se_subsystem_dev *se_dev,
                          char *b)
{
    struct pscsi_hba_virt *phv = hba->hba_ptr;
        struct pscsi_dev_virt *pdv = se_dev->se_dev_su_ptr;
    struct scsi_device *sd = pdv->pdv_sd;
    unsigned char host_id[16];
    ssize_t bl;
    int i;

    if (phv->phv_mode == PHV_VIRTUAL_HOST_ID)
        snprintf(host_id, 16, "%d", pdv->pdv_host_id);
    else
        snprintf(host_id, 16, "PHBA Mode");

    bl = sprintf(b, "SCSI Device Bus Location:"
        " Channel ID: %d Target ID: %d LUN: %d Host ID: %s\n",
        pdv->pdv_channel_id, pdv->pdv_target_id, pdv->pdv_lun_id,
        host_id);

    if (sd) {
        bl += sprintf(b + bl, "        ");
        bl += sprintf(b + bl, "Vendor: ");
        for (i = 0; i < 8; i++) {
            if (ISPRINT(sd->vendor[i]))   /* printable character? */
                bl += sprintf(b + bl, "%c", sd->vendor[i]);
            else
                bl += sprintf(b + bl, " ");
        }
        bl += sprintf(b + bl, " Model: ");
        for (i = 0; i < 16; i++) {
            if (ISPRINT(sd->model[i]))   /* printable character ? */
                bl += sprintf(b + bl, "%c", sd->model[i]);
            else
                bl += sprintf(b + bl, " ");
        }
        bl += sprintf(b + bl, " Rev: ");
        for (i = 0; i < 4; i++) {
            if (ISPRINT(sd->rev[i]))   /* printable character ? */
                bl += sprintf(b + bl, "%c", sd->rev[i]);
            else
                bl += sprintf(b + bl, " ");
        }
        bl += sprintf(b + bl, "\n");
    }
    return bl;
}

static void pscsi_bi_endio(struct bio *bio, int error)
{
    bio_put(bio);
}

static inline struct bio *pscsi_get_bio(int sg_num)
{
    struct bio *bio;
    /*
     * Use bio_malloc() following the comment in for bio -> struct request
     * in block/blk-core.c:blk_make_request()
     */
    bio = bio_kmalloc(GFP_KERNEL, sg_num);
    if (!bio) {
        pr_err("PSCSI: bio_kmalloc() failed\n");
        return NULL;
    }
    bio->bi_end_io = pscsi_bi_endio;

    return bio;
}

static int pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl,
        u32 sgl_nents, enum dma_data_direction data_direction,
        struct bio **hbio)
{
    struct pscsi_dev_virt *pdv = cmd->se_dev->dev_ptr;
    struct bio *bio = NULL, *tbio = NULL;
    struct page *page;
    struct scatterlist *sg;
    u32 data_len = cmd->data_length, i, len, bytes, off;
    int nr_pages = (cmd->data_length + sgl[0].offset +
            PAGE_SIZE - 1) >> PAGE_SHIFT;
    int nr_vecs = 0, rc;
    int rw = (data_direction == DMA_TO_DEVICE);

    *hbio = NULL;

    pr_debug("PSCSI: nr_pages: %d\n", nr_pages);

    for_each_sg(sgl, sg, sgl_nents, i) {
        page = sg_page(sg);
        off = sg->offset;
        len = sg->length;

        pr_debug("PSCSI: i: %d page: %p len: %d off: %d\n", i,
            page, len, off);

        while (len > 0 && data_len > 0) {
            bytes = min_t(unsigned int, len, PAGE_SIZE - off);
            bytes = min(bytes, data_len);

            if (!bio) {
                nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
                nr_pages -= nr_vecs;
                /*
                 * Calls bio_kmalloc() and sets bio->bi_end_io()
                 */
                bio = pscsi_get_bio(nr_vecs);
                if (!bio)
                    goto fail;

                if (rw)
                    bio->bi_rw |= REQ_WRITE;

                pr_debug("PSCSI: Allocated bio: %p,"
                    " dir: %s nr_vecs: %d\n", bio,
                    (rw) ? "rw" : "r", nr_vecs);
                /*
                 * Set *hbio pointer to handle the case:
                 * nr_pages > BIO_MAX_PAGES, where additional
                 * bios need to be added to complete a given
                 * command.
                 */
                if (!*hbio)
                    *hbio = tbio = bio;
                else
                    tbio = tbio->bi_next = bio;
            }

            pr_debug("PSCSI: Calling bio_add_pc_page() i: %d"
                " bio: %p page: %p len: %d off: %d\n", i, bio,
                page, len, off);

            rc = bio_add_pc_page(pdv->pdv_sd->request_queue,
                    bio, page, bytes, off);
            if (rc != bytes)
                goto fail;

            pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
                bio->bi_vcnt, nr_vecs);

            if (bio->bi_vcnt > nr_vecs) {
                pr_debug("PSCSI: Reached bio->bi_vcnt max:"
                    " %d i: %d bio: %p, allocating another"
                    " bio\n", bio->bi_vcnt, i, bio);
                /*
                 * Clear the pointer so that another bio will
                 * be allocated with pscsi_get_bio() above, the
                 * current bio has already been set *tbio and
                 * bio->bi_next.
                 */
                bio = NULL;
            }

            page++;
            len -= bytes;
            data_len -= bytes;
            off = 0;
        }
    }

    return sgl_nents;
fail:
    while (*hbio) {
        bio = *hbio;
        *hbio = (*hbio)->bi_next;
        bio->bi_next = NULL;
        bio_endio(bio, 0);  /* XXX: should be error */
    }
    cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
    return -ENOMEM;
}

/*
 * Clear a lun set in the cdb if the initiator talking to use spoke
 * and old standards version, as we can't assume the underlying device
 * won't choke up on it.
 */
static inline void pscsi_clear_cdb_lun(unsigned char *cdb)
{
    switch (cdb[0]) {
    case READ_10: /* SBC - RDProtect */
    case READ_12: /* SBC - RDProtect */
    case READ_16: /* SBC - RDProtect */
    case SEND_DIAGNOSTIC: /* SPC - SELF-TEST Code */
    case VERIFY: /* SBC - VRProtect */
    case VERIFY_16: /* SBC - VRProtect */
    case WRITE_VERIFY: /* SBC - VRProtect */
    case WRITE_VERIFY_12: /* SBC - VRProtect */
    case MAINTENANCE_IN: /* SPC - Parameter Data Format for SA RTPG */
        break;
    default:
        cdb[1] &= 0x1f; /* clear logical unit number */
        break;
    }
}

static int pscsi_parse_cdb(struct se_cmd *cmd)
{
    unsigned char *cdb = cmd->t_task_cdb;
    unsigned int dummy_size;
    int ret;

    if (cmd->se_cmd_flags & SCF_BIDI) {
        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        return -EINVAL;
    }

    pscsi_clear_cdb_lun(cdb);

    /*
     * For REPORT LUNS we always need to emulate the response, for everything
     * else the default for pSCSI is to pass the command to the underlying
     * LLD / physical hardware.
     */
    switch (cdb[0]) {
    case REPORT_LUNS:
        ret = spc_parse_cdb(cmd, &dummy_size);
        if (ret)
            return ret;
        break;
    case READ_6:
    case READ_10:
    case READ_12:
    case READ_16:
    case WRITE_6:
    case WRITE_10:
    case WRITE_12:
    case WRITE_16:
    case WRITE_VERIFY:
        cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
        /* FALLTHROUGH*/
    default:
        cmd->execute_cmd = pscsi_execute_cmd;
        break;
    }

    return 0;
}

static int pscsi_execute_cmd(struct se_cmd *cmd)
{
    struct scatterlist *sgl = cmd->t_data_sg;
    u32 sgl_nents = cmd->t_data_nents;
    enum dma_data_direction data_direction = cmd->data_direction;
    struct pscsi_dev_virt *pdv = cmd->se_dev->dev_ptr;
    struct pscsi_plugin_task *pt;
    struct request *req;
    struct bio *hbio;
    int ret;

    /*
     * Dynamically alloc cdb space, since it may be larger than
     * TCM_MAX_COMMAND_SIZE
     */
    pt = kzalloc(sizeof(*pt) + scsi_command_size(cmd->t_task_cdb), GFP_KERNEL);
    if (!pt) {
        cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
        return -ENOMEM;
    }
    cmd->priv = pt;

    memcpy(pt->pscsi_cdb, cmd->t_task_cdb,
        scsi_command_size(cmd->t_task_cdb));

    if (!sgl) {
        req = blk_get_request(pdv->pdv_sd->request_queue,
                (data_direction == DMA_TO_DEVICE),
                GFP_KERNEL);
        if (!req || IS_ERR(req)) {
            pr_err("PSCSI: blk_get_request() failed: %ld\n",
                    req ? IS_ERR(req) : -ENOMEM);
            cmd->scsi_sense_reason =
                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
            goto fail;
        }
    } else {
        BUG_ON(!cmd->data_length);

        ret = pscsi_map_sg(cmd, sgl, sgl_nents, data_direction, &hbio);
        if (ret < 0) {
            cmd->scsi_sense_reason =
                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
            goto fail;
        }

        req = blk_make_request(pdv->pdv_sd->request_queue, hbio,
                       GFP_KERNEL);
        if (IS_ERR(req)) {
            pr_err("pSCSI: blk_make_request() failed\n");
            goto fail_free_bio;
        }
    }

    req->cmd_type = REQ_TYPE_BLOCK_PC;
    req->end_io = pscsi_req_done;
    req->end_io_data = cmd;
    req->cmd_len = scsi_command_size(pt->pscsi_cdb);
    req->cmd = &pt->pscsi_cdb[0];
    req->sense = &pt->pscsi_sense[0];
    req->sense_len = 0;
    if (pdv->pdv_sd->type == TYPE_DISK)
        req->timeout = PS_TIMEOUT_DISK;
    else
        req->timeout = PS_TIMEOUT_OTHER;
    req->retries = PS_RETRY;

    blk_execute_rq_nowait(pdv->pdv_sd->request_queue, NULL, req,
            (cmd->sam_task_attr == MSG_HEAD_TAG),
            pscsi_req_done);

    return 0;

fail_free_bio:
    while (hbio) {
        struct bio *bio = hbio;
        hbio = hbio->bi_next;
        bio->bi_next = NULL;
        bio_endio(bio, 0);  /* XXX: should be error */
    }
    cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
fail:
    kfree(pt);
    return -ENOMEM;
}

/*  pscsi_get_device_rev():
 *
 *
 */
static u32 pscsi_get_device_rev(struct se_device *dev)
{
    struct pscsi_dev_virt *pdv = dev->dev_ptr;
    struct scsi_device *sd = pdv->pdv_sd;

    return (sd->scsi_level - 1) ? sd->scsi_level - 1 : 1;
}

/*  pscsi_get_device_type():
 *
 *
 */
static u32 pscsi_get_device_type(struct se_device *dev)
{
    struct pscsi_dev_virt *pdv = dev->dev_ptr;
    struct scsi_device *sd = pdv->pdv_sd;

    return sd->type;
}

static sector_t pscsi_get_blocks(struct se_device *dev)
{
    struct pscsi_dev_virt *pdv = dev->dev_ptr;

    if (pdv->pdv_bd && pdv->pdv_bd->bd_part)
        return pdv->pdv_bd->bd_part->nr_sects;

    dump_stack();
    return 0;
}

static void pscsi_req_done(struct request *req, int uptodate)
{
    struct se_cmd *cmd = req->end_io_data;
    struct pscsi_plugin_task *pt = cmd->priv;

    pt->pscsi_result = req->errors;
    pt->pscsi_resid = req->resid_len;

    cmd->scsi_status = status_byte(pt->pscsi_result) << 1;
    if (cmd->scsi_status) {
        pr_debug("PSCSI Status Byte exception at cmd: %p CDB:"
            " 0x%02x Result: 0x%08x\n", cmd, pt->pscsi_cdb[0],
            pt->pscsi_result);
    }

    switch (host_byte(pt->pscsi_result)) {
    case DID_OK:
        target_complete_cmd(cmd, cmd->scsi_status);
        break;
    default:
        pr_debug("PSCSI Host Byte exception at cmd: %p CDB:"
            " 0x%02x Result: 0x%08x\n", cmd, pt->pscsi_cdb[0],
            pt->pscsi_result);
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
        break;
    }

    __blk_put_request(req->q, req);
    kfree(pt);
}

static struct se_subsystem_api pscsi_template = {
    .name           = "pscsi",
    .owner          = THIS_MODULE,
    .transport_type     = TRANSPORT_PLUGIN_PHBA_PDEV,
    .attach_hba     = pscsi_attach_hba,
    .detach_hba     = pscsi_detach_hba,
    .pmode_enable_hba   = pscsi_pmode_enable_hba,
    .allocate_virtdevice    = pscsi_allocate_virtdevice,
    .create_virtdevice  = pscsi_create_virtdevice,
    .free_device        = pscsi_free_device,
    .transport_complete = pscsi_transport_complete,
    .parse_cdb      = pscsi_parse_cdb,
    .check_configfs_dev_params = pscsi_check_configfs_dev_params,
    .set_configfs_dev_params = pscsi_set_configfs_dev_params,
    .show_configfs_dev_params = pscsi_show_configfs_dev_params,
    .get_device_rev     = pscsi_get_device_rev,
    .get_device_type    = pscsi_get_device_type,
    .get_blocks     = pscsi_get_blocks,
};

static int __init pscsi_module_init(void)
{
    return transport_subsystem_register(&pscsi_template);
}

static void pscsi_module_exit(void)
{
    transport_subsystem_release(&pscsi_template);
}

MODULE_DESCRIPTION("TCM PSCSI subsystem plugin");
MODULE_AUTHOR("[email protected]");
MODULE_LICENSE("GPL");

module_init(pscsi_module_init);
module_exit(pscsi_module_exit);