// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * Filename:  target_core_pscsi.c
 *
 * This file contains the generic target mode <-> Linux SCSI subsystem plugin.
 *
 * (c) Copyright 2003-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 ******************************************************************************/

#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/cdrom.h>
#include <linux/ratelimit.h>
#include <linux/module.h>
#include <linux/unaligned.h>

#include <scsi/scsi_device.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_internal.h"
#include "target_core_pscsi.h"

static inline struct pscsi_dev_virt *PSCSI_DEV(struct se_device *dev)
{
        return container_of(dev, struct pscsi_dev_virt, dev);
}

static sense_reason_t pscsi_execute_cmd(struct se_cmd *cmd);
static enum rq_end_io_ret pscsi_req_done(struct request *, blk_status_t,
                                         const struct io_comp_batch *);

/*      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_obj(struct pscsi_hba_virt);
        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_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 (!sh) {
                pr_err("pSCSI: Unable to locate SCSI Host for"
                        " phv_host_id: %d\n", phv->phv_host_id);
                return -EINVAL;
        }

        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)
                goto out_free;

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

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

        /*
         * If MODE_SENSE still returns zero, set the default value to 1024.
         */
        sdev->sector_size = get_unaligned_be24(&buf[9]);
out_free:
        if (!sdev->sector_size)
                sdev->sector_size = 1024;

        kfree(buf);
}

static void
pscsi_set_inquiry_info(struct scsi_device *sdev, struct t10_wwn *wwn)
{
        if (sdev->inquiry_len < INQUIRY_LEN)
                return;
        /*
         * Use sdev->inquiry data from drivers/scsi/scsi_scan.c:scsi_add_lun()
         */
        BUILD_BUG_ON(sizeof(wwn->vendor) != INQUIRY_VENDOR_LEN + 1);
        snprintf(wwn->vendor, sizeof(wwn->vendor),
                 "%." __stringify(INQUIRY_VENDOR_LEN) "s", sdev->vendor);
        BUILD_BUG_ON(sizeof(wwn->model) != INQUIRY_MODEL_LEN + 1);
        snprintf(wwn->model, sizeof(wwn->model),
                 "%." __stringify(INQUIRY_MODEL_LEN) "s", sdev->model);
        BUILD_BUG_ON(sizeof(wwn->revision) != INQUIRY_REVISION_LEN + 1);
        snprintf(wwn->revision, sizeof(wwn->revision),
                 "%." __stringify(INQUIRY_REVISION_LEN) "s", sdev->rev);
}

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 */
        put_unaligned_be16(INQUIRY_VPD_SERIAL_LEN, &cdb[3]);

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

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

        wwn->t10_dev->dev_flags |= DF_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 */
        put_unaligned_be16(INQUIRY_VPD_DEVICE_IDENTIFIER_LEN, &cdb[3]);

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

        page_len = get_unaligned_be16(&buf[2]);
        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_obj(struct t10_vpd);
                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);
}

static int pscsi_add_device_to_list(struct se_device *dev,
                struct scsi_device *sd)
{
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct request_queue *q = sd->request_queue;

        pdv->pdv_sd = sd;

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

                pr_err("Set broken SCSI Device %d:%d:%llu"
                        " queue_depth to %d\n", sd->channel, sd->id,
                                sd->lun, sd->queue_depth);
        }

        dev->dev_attrib.hw_block_size =
                min_not_zero((int)sd->sector_size, 512);
        dev->dev_attrib.hw_max_sectors =
                min_not_zero(sd->host->max_sectors, queue_max_hw_sectors(q));
        dev->dev_attrib.hw_queue_depth = sd->queue_depth;

        /*
         * Setup our standard INQUIRY info into se_dev->t10_wwn
         */
        pscsi_set_inquiry_info(sd, &dev->t10_wwn);

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

        /*
         * For TYPE_TAPE, attempt to determine blocksize with MODE_SENSE.
         */
        if (sd->type == TYPE_TAPE) {
                pscsi_tape_read_blocksize(dev, sd);
                dev->dev_attrib.hw_block_size = sd->sector_size;
        }
        return 0;
}

static struct se_device *pscsi_alloc_device(struct se_hba *hba,
                const char *name)
{
        struct pscsi_dev_virt *pdv;

        pdv = kzalloc_obj(struct pscsi_dev_virt);
        if (!pdv) {
                pr_err("Unable to allocate memory for struct pscsi_dev_virt\n");
                return NULL;
        }

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

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static int pscsi_create_type_disk(struct se_device *dev, struct scsi_device *sd)
        __releases(sh->host_lock)
{
        struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct Scsi_Host *sh = sd->host;
        struct file *bdev_file;
        int ret;

        if (scsi_device_get(sd)) {
                pr_err("scsi_device_get() failed for %d:%d:%d:%llu\n",
                        sh->host_no, sd->channel, sd->id, sd->lun);
                spin_unlock_irq(sh->host_lock);
                return -EIO;
        }
        spin_unlock_irq(sh->host_lock);
        /*
         * Claim exclusive struct block_device access to struct scsi_device
         * for TYPE_DISK and TYPE_ZBC using supplied udev_path
         */
        bdev_file = bdev_file_open_by_path(dev->udev_path,
                                BLK_OPEN_WRITE | BLK_OPEN_READ, pdv, NULL);
        if (IS_ERR(bdev_file)) {
                pr_err("pSCSI: bdev_file_open_by_path() failed\n");
                scsi_device_put(sd);
                return PTR_ERR(bdev_file);
        }
        pdv->pdv_bdev_file = bdev_file;

        ret = pscsi_add_device_to_list(dev, sd);
        if (ret) {
                fput(bdev_file);
                scsi_device_put(sd);
                return ret;
        }

        pr_debug("CORE_PSCSI[%d] - Added TYPE_%s for %d:%d:%d:%llu\n",
                phv->phv_host_id, sd->type == TYPE_DISK ? "DISK" : "ZBC",
                sh->host_no, sd->channel, sd->id, sd->lun);
        return 0;
}

/*
 * Called with struct Scsi_Host->host_lock called.
 */
static int pscsi_create_type_nondisk(struct se_device *dev, struct scsi_device *sd)
        __releases(sh->host_lock)
{
        struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
        struct Scsi_Host *sh = sd->host;
        int ret;

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

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

        return 0;
}

static int pscsi_configure_device(struct se_device *dev)
{
        struct se_hba *hba = dev->se_hba;
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct scsi_device *sd;
        struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
        struct Scsi_Host *sh = phv->phv_lld_host;
        int legacy_mode_enable = 0;
        int ret;

        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;
        }

        /*
         * 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 -ENODEV;
                }
                /*
                 * For the newer PHV_VIRTUAL_HOST_ID struct scsi_device
                 * reference, we enforce that udev_path has been set
                 */
                if (!(dev->dev_flags & DF_USING_UDEV_PATH)) {
                        pr_err("pSCSI: udev_path attribute has not"
                                " been set before ENABLE=1\n");
                        return -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)) {
                        if (hba->dev_count) {
                                pr_err("pSCSI: Unable to set hba_mode"
                                        " with active devices\n");
                                return -EEXIST;
                        }

                        if (pscsi_pmode_enable_hba(hba, 1) != 1)
                                return -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 (!sh) {
                                pr_err("pSCSI: Unable to locate"
                                        " pdv_host_id: %d\n", pdv->pdv_host_id);
                                return -EINVAL;
                        }
                        pdv->pdv_lld_host = 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 -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 pscsi_add_device_to_list() to register
                 * struct scsi_device with target_core_mod.
                 */
                switch (sd->type) {
                case TYPE_DISK:
                case TYPE_ZBC:
                        ret = pscsi_create_type_disk(dev, sd);
                        break;
                default:
                        ret = pscsi_create_type_nondisk(dev, sd);
                        break;
                }

                if (ret) {
                        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 ret;
                }
                return 0;
        }
        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 -ENODEV;
}

static void pscsi_dev_call_rcu(struct rcu_head *p)
{
        struct se_device *dev = container_of(p, struct se_device, rcu_head);
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);

        kfree(pdv);
}

static void pscsi_free_device(struct se_device *dev)
{
        call_rcu(&dev->rcu_head, pscsi_dev_call_rcu);
}

static void pscsi_destroy_device(struct se_device *dev)
{
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct pscsi_hba_virt *phv = dev->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 or TYPE_ZBC
                 * from pscsi_create_type_disk()
                 */
                if ((sd->type == TYPE_DISK || sd->type == TYPE_ZBC) &&
                    pdv->pdv_bdev_file) {
                        fput(pdv->pdv_bdev_file);
                        pdv->pdv_bdev_file = 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);
                else if (pdv->pdv_lld_host)
                        scsi_host_put(pdv->pdv_lld_host);

                scsi_device_put(sd);

                pdv->pdv_sd = NULL;
        }
}

static void pscsi_complete_cmd(struct se_cmd *cmd, u8 scsi_status,
                               unsigned char *req_sense, int valid_data)
{
        struct pscsi_dev_virt *pdv = PSCSI_DEV(cmd->se_dev);
        struct scsi_device *sd = pdv->pdv_sd;
        unsigned char *cdb = cmd->priv;

        /*
         * Special case for REPORT_LUNs which is emulated and not passed on.
         */
        if (!cdb)
                return;

        /*
         * Hack to make sure that Write-Protect modepage is set if R/O mode is
         * forced.
         */
        if (!cmd->data_length)
                goto after_mode_sense;

        if (((cdb[0] == MODE_SENSE) || (cdb[0] == MODE_SENSE_10)) &&
            scsi_status == SAM_STAT_GOOD) {
                bool read_only = target_lun_is_rdonly(cmd);

                if (read_only) {
                        unsigned char *buf;

                        buf = transport_kmap_data_sg(cmd);
                        if (!buf) {
                                ; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */
                        } else {
                                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)) &&
             scsi_status == SAM_STAT_GOOD) {
                unsigned char *buf;
                u16 bdl;
                u32 blocksize;

                buf = sg_virt(&cmd->t_data_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 = get_unaligned_be16(&buf[6]);

                if (!bdl)
                        goto after_mode_select;

                if (cdb[0] == MODE_SELECT)
                        blocksize = get_unaligned_be24(&buf[9]);
                else
                        blocksize = get_unaligned_be24(&buf[13]);

                sd->sector_size = blocksize;
        }
after_mode_select:

        if (scsi_status == SAM_STAT_CHECK_CONDITION) {
                transport_copy_sense_to_cmd(cmd, req_sense);

                /*
                 * check for TAPE device reads with
                 * FM/EOM/ILI set, so that we can get data
                 * back despite framework assumption that a
                 * check condition means there is no data
                 */
                if (sd->type == TYPE_TAPE && valid_data &&
                    cmd->data_direction == DMA_FROM_DEVICE) {
                        /*
                         * is sense data valid, fixed format,
                         * and have FM, EOM, or ILI set?
                         */
                        if (req_sense[0] == 0xf0 &&     /* valid, fixed format */
                            req_sense[2] & 0xe0 &&      /* FM, EOM, or ILI */
                            (req_sense[2] & 0xf) == 0) { /* key==NO_SENSE */
                                pr_debug("Tape FM/EOM/ILI status detected. Treat as normal read.\n");
                                cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
                        }
                }
        }
}

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_device *dev,
                const char *page, ssize_t count)
{
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct pscsi_hba_virt *phv = dev->se_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;
                        }
                        ret = match_int(args, &arg);
                        if (ret)
                                goto out;
                        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:
                        ret = match_int(args, &arg);
                        if (ret)
                                goto out;
                        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:
                        ret = match_int(args, &arg);
                        if (ret)
                                goto out;
                        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:
                        ret = match_int(args, &arg);
                        if (ret)
                                goto out;
                        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_show_configfs_dev_params(struct se_device *dev, char *b)
{
        struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
        struct scsi_device *sd = pdv->pdv_sd;
        unsigned char host_id[16];
        ssize_t bl;

        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, "        Vendor: %."
                        __stringify(INQUIRY_VENDOR_LEN) "s", sd->vendor);
                bl += sprintf(b + bl, " Model: %."
                        __stringify(INQUIRY_MODEL_LEN) "s", sd->model);
                bl += sprintf(b + bl, " Rev: %."
                        __stringify(INQUIRY_REVISION_LEN) "s\n", sd->rev);
        }
        return bl;
}

static void pscsi_bi_endio(struct bio *bio)
{
        bio_uninit(bio);
        kfree(bio);
}

static sense_reason_t
pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
                struct request *req)
{
        struct bio *bio = 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 = (cmd->data_direction == DMA_TO_DEVICE);

        BUG_ON(!cmd->data_length);

        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);

                /*
                 * We only have one page of data in each sg element,
                 * we can not cross a page boundary.
                 */
                if (off + len > PAGE_SIZE)
                        goto fail;

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

                        if (!bio) {
new_bio:
                                nr_vecs = bio_max_segs(nr_pages);
                                bio = bio_kmalloc(nr_vecs, GFP_KERNEL);
                                if (!bio)
                                        goto fail;
                                bio_init_inline(bio, NULL, nr_vecs,
                                         rw ? REQ_OP_WRITE : REQ_OP_READ);
                                bio->bi_end_io = pscsi_bi_endio;

                                pr_debug("PSCSI: Allocated bio: %p,"
                                        " dir: %s nr_vecs: %d\n", bio,
                                        (rw) ? "rw" : "r", nr_vecs);
                        }

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

                        rc = bio_add_page(bio, page, bytes, off);
                        pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
                                bio_segments(bio), nr_vecs);
                        if (rc != bytes) {
                                pr_debug("PSCSI: Reached bio->bi_vcnt max:"
                                        " %d i: %d bio: %p, allocating another"
                                        " bio\n", bio->bi_vcnt, i, bio);

                                rc = blk_rq_append_bio(req, bio);
                                if (rc) {
                                        pr_err("pSCSI: failed to append bio\n");
                                        goto fail;
                                }

                                goto new_bio;
                        }

                        data_len -= bytes;
                }
        }

        if (bio) {
                rc = blk_rq_append_bio(req, bio);
                if (rc) {
                        pr_err("pSCSI: failed to append bio\n");
                        goto fail;
                }
        }

        return 0;
fail:
        if (bio) {
                bio_uninit(bio);
                kfree(bio);
        }
        while (req->bio) {
                bio = req->bio;
                req->bio = bio->bi_next;
                bio_uninit(bio);
                kfree(bio);
        }
        req->biotail = NULL;
        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}

static sense_reason_t
pscsi_parse_cdb(struct se_cmd *cmd)
{
        if (cmd->se_cmd_flags & SCF_BIDI)
                return TCM_UNSUPPORTED_SCSI_OPCODE;

        return passthrough_parse_cdb(cmd, pscsi_execute_cmd);
}

static sense_reason_t
pscsi_execute_cmd(struct se_cmd *cmd)
{
        struct scatterlist *sgl = cmd->t_data_sg;
        u32 sgl_nents = cmd->t_data_nents;
        struct pscsi_dev_virt *pdv = PSCSI_DEV(cmd->se_dev);
        struct scsi_cmnd *scmd;
        struct request *req;
        sense_reason_t ret;

        req = scsi_alloc_request(pdv->pdv_sd->request_queue,
                        cmd->data_direction == DMA_TO_DEVICE ?
                        REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(req))
                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

        if (sgl) {
                ret = pscsi_map_sg(cmd, sgl, sgl_nents, req);
                if (ret)
                        goto fail_put_request;
        }

        req->end_io = pscsi_req_done;
        req->end_io_data = cmd;

        scmd = blk_mq_rq_to_pdu(req);
        scmd->cmd_len = scsi_command_size(cmd->t_task_cdb);
        if (scmd->cmd_len > sizeof(scmd->cmnd)) {
                ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                goto fail_put_request;
        }
        memcpy(scmd->cmnd, cmd->t_task_cdb, scmd->cmd_len);

        if (pdv->pdv_sd->type == TYPE_DISK ||
            pdv->pdv_sd->type == TYPE_ZBC)
                req->timeout = PS_TIMEOUT_DISK;
        else
                req->timeout = PS_TIMEOUT_OTHER;
        scmd->allowed = PS_RETRY;

        cmd->priv = scmd->cmnd;

        blk_execute_rq_nowait(req, cmd->sam_task_attr == TCM_HEAD_TAG);

        return 0;

fail_put_request:
        blk_mq_free_request(req);
        return ret;
}

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

        return (sd) ? sd->type : TYPE_NO_LUN;
}

static sector_t pscsi_get_blocks(struct se_device *dev)
{
        struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);

        if (pdv->pdv_bdev_file)
                return bdev_nr_sectors(file_bdev(pdv->pdv_bdev_file));
        return 0;
}

static enum rq_end_io_ret pscsi_req_done(struct request *req,
                                         blk_status_t status,
                                         const struct io_comp_batch *iob)
{
        struct se_cmd *cmd = req->end_io_data;
        struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
        enum sam_status scsi_status = scmd->result & 0xff;
        int valid_data = cmd->data_length - scmd->resid_len;
        u8 *cdb = cmd->priv;

        if (scsi_status != SAM_STAT_GOOD) {
                pr_debug("PSCSI Status Byte exception at cmd: %p CDB:"
                        " 0x%02x Result: 0x%08x\n", cmd, cdb[0], scmd->result);
        }

        pscsi_complete_cmd(cmd, scsi_status, scmd->sense_buffer, valid_data);

        switch (host_byte(scmd->result)) {
        case DID_OK:
                target_complete_cmd_with_length(cmd, scsi_status, valid_data);
                break;
        default:
                pr_debug("PSCSI Host Byte exception at cmd: %p CDB:"
                        " 0x%02x Result: 0x%08x\n", cmd, cdb[0], scmd->result);
                target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
                break;
        }

        blk_mq_free_request(req);
        return RQ_END_IO_NONE;
}

static const struct target_backend_ops pscsi_ops = {
        .name                   = "pscsi",
        .owner                  = THIS_MODULE,
        .transport_flags_default = TRANSPORT_FLAG_PASSTHROUGH |
                                   TRANSPORT_FLAG_PASSTHROUGH_ALUA |
                                   TRANSPORT_FLAG_PASSTHROUGH_PGR,
        .attach_hba             = pscsi_attach_hba,
        .detach_hba             = pscsi_detach_hba,
        .pmode_enable_hba       = pscsi_pmode_enable_hba,
        .alloc_device           = pscsi_alloc_device,
        .configure_device       = pscsi_configure_device,
        .destroy_device         = pscsi_destroy_device,
        .free_device            = pscsi_free_device,
        .parse_cdb              = pscsi_parse_cdb,
        .set_configfs_dev_params = pscsi_set_configfs_dev_params,
        .show_configfs_dev_params = pscsi_show_configfs_dev_params,
        .get_device_type        = pscsi_get_device_type,
        .get_blocks             = pscsi_get_blocks,
        .tb_dev_attrib_attrs    = passthrough_attrib_attrs,
};

static int __init pscsi_module_init(void)
{
        return transport_backend_register(&pscsi_ops);
}

static void __exit pscsi_module_exit(void)
{
        target_backend_unregister(&pscsi_ops);
}

MODULE_DESCRIPTION("TCM PSCSI subsystem plugin");
MODULE_AUTHOR("nab@Linux-iSCSI.org");
MODULE_LICENSE("GPL");

module_init(pscsi_module_init);
module_exit(pscsi_module_exit);