target: make the se_task task_state_active a normal bool

[linux-2.6/btrfs-unstable.git] / drivers / target / target_core_transport.c

/*******************************************************************************
 * Filename:  target_core_transport.c
 *
 * This file contains the Generic Target Engine Core.
 *
 * Copyright (c) 2002, 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 <nab@kernel.org>
 *
 * 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/net.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/in.h>
#include <linux/cdrom.h>
#include <linux/module.h>
#include <asm/unaligned.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_tcq.h>

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

#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
#include "target_core_ua.h"

static int sub_api_initialized;

static struct workqueue_struct *target_completion_wq;
static struct kmem_cache *se_sess_cache;
struct kmem_cache *se_tmr_req_cache;
struct kmem_cache *se_ua_cache;
struct kmem_cache *t10_pr_reg_cache;
struct kmem_cache *t10_alua_lu_gp_cache;
struct kmem_cache *t10_alua_lu_gp_mem_cache;
struct kmem_cache *t10_alua_tg_pt_gp_cache;
struct kmem_cache *t10_alua_tg_pt_gp_mem_cache;

static int transport_generic_write_pending(struct se_cmd *);
static int transport_processing_thread(void *param);
static int __transport_execute_tasks(struct se_device *dev);
static void transport_complete_task_attr(struct se_cmd *cmd);
static void transport_handle_queue_full(struct se_cmd *cmd,
                struct se_device *dev);
static void transport_free_dev_tasks(struct se_cmd *cmd);
static int transport_generic_get_mem(struct se_cmd *cmd);
static void transport_put_cmd(struct se_cmd *cmd);
static void transport_remove_cmd_from_queue(struct se_cmd *cmd);
static int transport_set_sense_codes(struct se_cmd *cmd, u8 asc, u8 ascq);
static void transport_generic_request_failure(struct se_cmd *);
static void target_complete_ok_work(struct work_struct *work);

int init_se_kmem_caches(void)
{
        se_tmr_req_cache = kmem_cache_create("se_tmr_cache",
                        sizeof(struct se_tmr_req), __alignof__(struct se_tmr_req),
                        0, NULL);
        if (!se_tmr_req_cache) {
                pr_err("kmem_cache_create() for struct se_tmr_req"
                                " failed\n");
                goto out;
        }
        se_sess_cache = kmem_cache_create("se_sess_cache",
                        sizeof(struct se_session), __alignof__(struct se_session),
                        0, NULL);
        if (!se_sess_cache) {
                pr_err("kmem_cache_create() for struct se_session"
                                " failed\n");
                goto out_free_tmr_req_cache;
        }
        se_ua_cache = kmem_cache_create("se_ua_cache",
                        sizeof(struct se_ua), __alignof__(struct se_ua),
                        0, NULL);
        if (!se_ua_cache) {
                pr_err("kmem_cache_create() for struct se_ua failed\n");
                goto out_free_sess_cache;
        }
        t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
                        sizeof(struct t10_pr_registration),
                        __alignof__(struct t10_pr_registration), 0, NULL);
        if (!t10_pr_reg_cache) {
                pr_err("kmem_cache_create() for struct t10_pr_registration"
                                " failed\n");
                goto out_free_ua_cache;
        }
        t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
                        sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
                        0, NULL);
        if (!t10_alua_lu_gp_cache) {
                pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
                                " failed\n");
                goto out_free_pr_reg_cache;
        }
        t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
                        sizeof(struct t10_alua_lu_gp_member),
                        __alignof__(struct t10_alua_lu_gp_member), 0, NULL);
        if (!t10_alua_lu_gp_mem_cache) {
                pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
                                "cache failed\n");
                goto out_free_lu_gp_cache;
        }
        t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
                        sizeof(struct t10_alua_tg_pt_gp),
                        __alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
        if (!t10_alua_tg_pt_gp_cache) {
                pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
                                "cache failed\n");
                goto out_free_lu_gp_mem_cache;
        }
        t10_alua_tg_pt_gp_mem_cache = kmem_cache_create(
                        "t10_alua_tg_pt_gp_mem_cache",
                        sizeof(struct t10_alua_tg_pt_gp_member),
                        __alignof__(struct t10_alua_tg_pt_gp_member),
                        0, NULL);
        if (!t10_alua_tg_pt_gp_mem_cache) {
                pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
                                "mem_t failed\n");
                goto out_free_tg_pt_gp_cache;
        }

        target_completion_wq = alloc_workqueue("target_completion",
                                               WQ_MEM_RECLAIM, 0);
        if (!target_completion_wq)
                goto out_free_tg_pt_gp_mem_cache;

        return 0;

out_free_tg_pt_gp_mem_cache:
        kmem_cache_destroy(t10_alua_tg_pt_gp_mem_cache);
out_free_tg_pt_gp_cache:
        kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
out_free_lu_gp_mem_cache:
        kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
out_free_lu_gp_cache:
        kmem_cache_destroy(t10_alua_lu_gp_cache);
out_free_pr_reg_cache:
        kmem_cache_destroy(t10_pr_reg_cache);
out_free_ua_cache:
        kmem_cache_destroy(se_ua_cache);
out_free_sess_cache:
        kmem_cache_destroy(se_sess_cache);
out_free_tmr_req_cache:
        kmem_cache_destroy(se_tmr_req_cache);
out:
        return -ENOMEM;
}

void release_se_kmem_caches(void)
{
        destroy_workqueue(target_completion_wq);
        kmem_cache_destroy(se_tmr_req_cache);
        kmem_cache_destroy(se_sess_cache);
        kmem_cache_destroy(se_ua_cache);
        kmem_cache_destroy(t10_pr_reg_cache);
        kmem_cache_destroy(t10_alua_lu_gp_cache);
        kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
        kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
        kmem_cache_destroy(t10_alua_tg_pt_gp_mem_cache);
}

/* This code ensures unique mib indexes are handed out. */
static DEFINE_SPINLOCK(scsi_mib_index_lock);
static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];

/*
 * Allocate a new row index for the entry type specified
 */
u32 scsi_get_new_index(scsi_index_t type)
{
        u32 new_index;

        BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));

        spin_lock(&scsi_mib_index_lock);
        new_index = ++scsi_mib_index[type];
        spin_unlock(&scsi_mib_index_lock);

        return new_index;
}

static void transport_init_queue_obj(struct se_queue_obj *qobj)
{
        atomic_set(&qobj->queue_cnt, 0);
        INIT_LIST_HEAD(&qobj->qobj_list);
        init_waitqueue_head(&qobj->thread_wq);
        spin_lock_init(&qobj->cmd_queue_lock);
}

void transport_subsystem_check_init(void)
{
        int ret;

        if (sub_api_initialized)
                return;

        ret = request_module("target_core_iblock");
        if (ret != 0)
                pr_err("Unable to load target_core_iblock\n");

        ret = request_module("target_core_file");
        if (ret != 0)
                pr_err("Unable to load target_core_file\n");

        ret = request_module("target_core_pscsi");
        if (ret != 0)
                pr_err("Unable to load target_core_pscsi\n");

        ret = request_module("target_core_stgt");
        if (ret != 0)
                pr_err("Unable to load target_core_stgt\n");

        sub_api_initialized = 1;
        return;
}

struct se_session *transport_init_session(void)
{
        struct se_session *se_sess;

        se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
        if (!se_sess) {
                pr_err("Unable to allocate struct se_session from"
                                " se_sess_cache\n");
                return ERR_PTR(-ENOMEM);
        }
        INIT_LIST_HEAD(&se_sess->sess_list);
        INIT_LIST_HEAD(&se_sess->sess_acl_list);
        INIT_LIST_HEAD(&se_sess->sess_cmd_list);
        INIT_LIST_HEAD(&se_sess->sess_wait_list);
        spin_lock_init(&se_sess->sess_cmd_lock);

        return se_sess;
}
EXPORT_SYMBOL(transport_init_session);

/*
 * Called with spin_lock_bh(&struct se_portal_group->session_lock called.
 */
void __transport_register_session(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct se_session *se_sess,
        void *fabric_sess_ptr)
{
        unsigned char buf[PR_REG_ISID_LEN];

        se_sess->se_tpg = se_tpg;
        se_sess->fabric_sess_ptr = fabric_sess_ptr;
        /*
         * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
         *
         * Only set for struct se_session's that will actually be moving I/O.
         * eg: *NOT* discovery sessions.
         */
        if (se_nacl) {
                /*
                 * If the fabric module supports an ISID based TransportID,
                 * save this value in binary from the fabric I_T Nexus now.
                 */
                if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
                        memset(&buf[0], 0, PR_REG_ISID_LEN);
                        se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
                                        &buf[0], PR_REG_ISID_LEN);
                        se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
                }
                spin_lock_irq(&se_nacl->nacl_sess_lock);
                /*
                 * The se_nacl->nacl_sess pointer will be set to the
                 * last active I_T Nexus for each struct se_node_acl.
                 */
                se_nacl->nacl_sess = se_sess;

                list_add_tail(&se_sess->sess_acl_list,
                              &se_nacl->acl_sess_list);
                spin_unlock_irq(&se_nacl->nacl_sess_lock);
        }
        list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);

        pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
                se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
}
EXPORT_SYMBOL(__transport_register_session);

void transport_register_session(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct se_session *se_sess,
        void *fabric_sess_ptr)
{
        spin_lock_bh(&se_tpg->session_lock);
        __transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
        spin_unlock_bh(&se_tpg->session_lock);
}
EXPORT_SYMBOL(transport_register_session);

void transport_deregister_session_configfs(struct se_session *se_sess)
{
        struct se_node_acl *se_nacl;
        unsigned long flags;
        /*
         * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
         */
        se_nacl = se_sess->se_node_acl;
        if (se_nacl) {
                spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
                list_del(&se_sess->sess_acl_list);
                /*
                 * If the session list is empty, then clear the pointer.
                 * Otherwise, set the struct se_session pointer from the tail
                 * element of the per struct se_node_acl active session list.
                 */
                if (list_empty(&se_nacl->acl_sess_list))
                        se_nacl->nacl_sess = NULL;
                else {
                        se_nacl->nacl_sess = container_of(
                                        se_nacl->acl_sess_list.prev,
                                        struct se_session, sess_acl_list);
                }
                spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
        }
}
EXPORT_SYMBOL(transport_deregister_session_configfs);

void transport_free_session(struct se_session *se_sess)
{
        kmem_cache_free(se_sess_cache, se_sess);
}
EXPORT_SYMBOL(transport_free_session);

void transport_deregister_session(struct se_session *se_sess)
{
        struct se_portal_group *se_tpg = se_sess->se_tpg;
        struct se_node_acl *se_nacl;
        unsigned long flags;

        if (!se_tpg) {
                transport_free_session(se_sess);
                return;
        }

        spin_lock_irqsave(&se_tpg->session_lock, flags);
        list_del(&se_sess->sess_list);
        se_sess->se_tpg = NULL;
        se_sess->fabric_sess_ptr = NULL;
        spin_unlock_irqrestore(&se_tpg->session_lock, flags);

        /*
         * Determine if we need to do extra work for this initiator node's
         * struct se_node_acl if it had been previously dynamically generated.
         */
        se_nacl = se_sess->se_node_acl;
        if (se_nacl) {
                spin_lock_irqsave(&se_tpg->acl_node_lock, flags);
                if (se_nacl->dynamic_node_acl) {
                        if (!se_tpg->se_tpg_tfo->tpg_check_demo_mode_cache(
                                        se_tpg)) {
                                list_del(&se_nacl->acl_list);
                                se_tpg->num_node_acls--;
                                spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);

                                core_tpg_wait_for_nacl_pr_ref(se_nacl);
                                core_free_device_list_for_node(se_nacl, se_tpg);
                                se_tpg->se_tpg_tfo->tpg_release_fabric_acl(se_tpg,
                                                se_nacl);
                                spin_lock_irqsave(&se_tpg->acl_node_lock, flags);
                        }
                }
                spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);
        }

        transport_free_session(se_sess);

        pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
                se_tpg->se_tpg_tfo->get_fabric_name());
}
EXPORT_SYMBOL(transport_deregister_session);

/*
 * Called with cmd->t_state_lock held.
 */
static void transport_all_task_dev_remove_state(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        struct se_task *task;
        unsigned long flags;

        if (!dev)
                return;

        list_for_each_entry(task, &cmd->t_task_list, t_list) {
                if (task->task_flags & TF_ACTIVE)
                        continue;

                spin_lock_irqsave(&dev->execute_task_lock, flags);
                if (task->t_state_active) {
                        pr_debug("Removed ITT: 0x%08x dev: %p task[%p]\n",
                                cmd->se_tfo->get_task_tag(cmd), dev, task);

                        list_del(&task->t_state_list);
                        atomic_dec(&cmd->t_task_cdbs_ex_left);
                        task->t_state_active = false;
                }
                spin_unlock_irqrestore(&dev->execute_task_lock, flags);
        }

}

/*      transport_cmd_check_stop():
 *
 *      'transport_off = 1' determines if t_transport_active should be cleared.
 *      'transport_off = 2' determines if task_dev_state should be removed.
 *
 *      A non-zero u8 t_state sets cmd->t_state.
 *      Returns 1 when command is stopped, else 0.
 */
static int transport_cmd_check_stop(
        struct se_cmd *cmd,
        int transport_off,
        u8 t_state)
{
        unsigned long flags;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        /*
         * Determine if IOCTL context caller in requesting the stopping of this
         * command for LUN shutdown purposes.
         */
        if (atomic_read(&cmd->transport_lun_stop)) {
                pr_debug("%s:%d atomic_read(&cmd->transport_lun_stop)"
                        " == TRUE for ITT: 0x%08x\n", __func__, __LINE__,
                        cmd->se_tfo->get_task_tag(cmd));

                atomic_set(&cmd->t_transport_active, 0);
                if (transport_off == 2)
                        transport_all_task_dev_remove_state(cmd);
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);

                complete(&cmd->transport_lun_stop_comp);
                return 1;
        }
        /*
         * Determine if frontend context caller is requesting the stopping of
         * this command for frontend exceptions.
         */
        if (atomic_read(&cmd->t_transport_stop)) {
                pr_debug("%s:%d atomic_read(&cmd->t_transport_stop) =="
                        " TRUE for ITT: 0x%08x\n", __func__, __LINE__,
                        cmd->se_tfo->get_task_tag(cmd));

                if (transport_off == 2)
                        transport_all_task_dev_remove_state(cmd);

                /*
                 * Clear struct se_cmd->se_lun before the transport_off == 2 handoff
                 * to FE.
                 */
                if (transport_off == 2)
                        cmd->se_lun = NULL;
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);

                complete(&cmd->t_transport_stop_comp);
                return 1;
        }
        if (transport_off) {
                atomic_set(&cmd->t_transport_active, 0);
                if (transport_off == 2) {
                        transport_all_task_dev_remove_state(cmd);
                        /*
                         * Clear struct se_cmd->se_lun before the transport_off == 2
                         * handoff to fabric module.
                         */
                        cmd->se_lun = NULL;
                        /*
                         * Some fabric modules like tcm_loop can release
                         * their internally allocated I/O reference now and
                         * struct se_cmd now.
                         *
                         * Fabric modules are expected to return '1' here if the
                         * se_cmd being passed is released at this point,
                         * or zero if not being released.
                         */
                        if (cmd->se_tfo->check_stop_free != NULL) {
                                spin_unlock_irqrestore(
                                        &cmd->t_state_lock, flags);

                                return cmd->se_tfo->check_stop_free(cmd);
                        }
                }
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);

                return 0;
        } else if (t_state)
                cmd->t_state = t_state;
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        return 0;
}

static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
{
        return transport_cmd_check_stop(cmd, 2, 0);
}

static void transport_lun_remove_cmd(struct se_cmd *cmd)
{
        struct se_lun *lun = cmd->se_lun;
        unsigned long flags;

        if (!lun)
                return;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (!atomic_read(&cmd->transport_dev_active)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                goto check_lun;
        }
        atomic_set(&cmd->transport_dev_active, 0);
        transport_all_task_dev_remove_state(cmd);
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);


check_lun:
        spin_lock_irqsave(&lun->lun_cmd_lock, flags);
        if (atomic_read(&cmd->transport_lun_active)) {
                list_del(&cmd->se_lun_node);
                atomic_set(&cmd->transport_lun_active, 0);
#if 0
                pr_debug("Removed ITT: 0x%08x from LUN LIST[%d]\n"
                        cmd->se_tfo->get_task_tag(cmd), lun->unpacked_lun);
#endif
        }
        spin_unlock_irqrestore(&lun->lun_cmd_lock, flags);
}

void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
{
        if (!cmd->se_tmr_req)
                transport_lun_remove_cmd(cmd);

        if (transport_cmd_check_stop_to_fabric(cmd))
                return;
        if (remove) {
                transport_remove_cmd_from_queue(cmd);
                transport_put_cmd(cmd);
        }
}

static void transport_add_cmd_to_queue(struct se_cmd *cmd, int t_state,
                bool at_head)
{
        struct se_device *dev = cmd->se_dev;
        struct se_queue_obj *qobj = &dev->dev_queue_obj;
        unsigned long flags;

        if (t_state) {
                spin_lock_irqsave(&cmd->t_state_lock, flags);
                cmd->t_state = t_state;
                atomic_set(&cmd->t_transport_active, 1);
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
        }

        spin_lock_irqsave(&qobj->cmd_queue_lock, flags);

        /* If the cmd is already on the list, remove it before we add it */
        if (!list_empty(&cmd->se_queue_node))
                list_del(&cmd->se_queue_node);
        else
                atomic_inc(&qobj->queue_cnt);

        if (at_head)
                list_add(&cmd->se_queue_node, &qobj->qobj_list);
        else
                list_add_tail(&cmd->se_queue_node, &qobj->qobj_list);
        atomic_set(&cmd->t_transport_queue_active, 1);
        spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);

        wake_up_interruptible(&qobj->thread_wq);
}

static struct se_cmd *
transport_get_cmd_from_queue(struct se_queue_obj *qobj)
{
        struct se_cmd *cmd;
        unsigned long flags;

        spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
        if (list_empty(&qobj->qobj_list)) {
                spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
                return NULL;
        }
        cmd = list_first_entry(&qobj->qobj_list, struct se_cmd, se_queue_node);

        atomic_set(&cmd->t_transport_queue_active, 0);

        list_del_init(&cmd->se_queue_node);
        atomic_dec(&qobj->queue_cnt);
        spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);

        return cmd;
}

static void transport_remove_cmd_from_queue(struct se_cmd *cmd)
{
        struct se_queue_obj *qobj = &cmd->se_dev->dev_queue_obj;
        unsigned long flags;

        spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
        if (!atomic_read(&cmd->t_transport_queue_active)) {
                spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
                return;
        }
        atomic_set(&cmd->t_transport_queue_active, 0);
        atomic_dec(&qobj->queue_cnt);
        list_del_init(&cmd->se_queue_node);
        spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);

        if (atomic_read(&cmd->t_transport_queue_active)) {
                pr_err("ITT: 0x%08x t_transport_queue_active: %d\n",
                        cmd->se_tfo->get_task_tag(cmd),
                        atomic_read(&cmd->t_transport_queue_active));
        }
}

/*
 * Completion function used by TCM subsystem plugins (such as FILEIO)
 * for queueing up response from struct se_subsystem_api->do_task()
 */
void transport_complete_sync_cache(struct se_cmd *cmd, int good)
{
        struct se_task *task = list_entry(cmd->t_task_list.next,
                                struct se_task, t_list);

        if (good) {
                cmd->scsi_status = SAM_STAT_GOOD;
                task->task_scsi_status = GOOD;
        } else {
                task->task_scsi_status = SAM_STAT_CHECK_CONDITION;
                task->task_se_cmd->scsi_sense_reason =
                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

        }

        transport_complete_task(task, good);
}
EXPORT_SYMBOL(transport_complete_sync_cache);

static void target_complete_failure_work(struct work_struct *work)
{
        struct se_cmd *cmd = container_of(work, struct se_cmd, work);

        transport_generic_request_failure(cmd);
}

/*      transport_complete_task():
 *
 *      Called from interrupt and non interrupt context depending
 *      on the transport plugin.
 */
void transport_complete_task(struct se_task *task, int success)
{
        struct se_cmd *cmd = task->task_se_cmd;
        struct se_device *dev = cmd->se_dev;
        unsigned long flags;
#if 0
        pr_debug("task: %p CDB: 0x%02x obj_ptr: %p\n", task,
                        cmd->t_task_cdb[0], dev);
#endif
        if (dev)
                atomic_inc(&dev->depth_left);

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        task->task_flags &= ~TF_ACTIVE;

        /*
         * See if any sense data exists, if so set the TASK_SENSE flag.
         * Also check for any other post completion work that needs to be
         * done by the plugins.
         */
        if (dev && dev->transport->transport_complete) {
                if (dev->transport->transport_complete(task) != 0) {
                        cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
                        task->task_flags |= TF_HAS_SENSE;
                        success = 1;
                }
        }

        /*
         * See if we are waiting for outstanding struct se_task
         * to complete for an exception condition
         */
        if (task->task_flags & TF_REQUEST_STOP) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                complete(&task->task_stop_comp);
                return;
        }

        if (!success)
                cmd->t_tasks_failed = 1;

        /*
         * Decrement the outstanding t_task_cdbs_left count.  The last
         * struct se_task from struct se_cmd will complete itself into the
         * device queue depending upon int success.
         */
        if (!atomic_dec_and_test(&cmd->t_task_cdbs_left)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return;
        }

        if (cmd->t_tasks_failed) {
                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                INIT_WORK(&cmd->work, target_complete_failure_work);
        } else {
                atomic_set(&cmd->t_transport_complete, 1);
                INIT_WORK(&cmd->work, target_complete_ok_work);
        }

        cmd->t_state = TRANSPORT_COMPLETE;
        atomic_set(&cmd->t_transport_active, 1);
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        queue_work(target_completion_wq, &cmd->work);
}
EXPORT_SYMBOL(transport_complete_task);

/*
 * Called by transport_add_tasks_from_cmd() once a struct se_cmd's
 * struct se_task list are ready to be added to the active execution list
 * struct se_device

 * Called with se_dev_t->execute_task_lock called.
 */
static inline int transport_add_task_check_sam_attr(
        struct se_task *task,
        struct se_task *task_prev,
        struct se_device *dev)
{
        /*
         * No SAM Task attribute emulation enabled, add to tail of
         * execution queue
         */
        if (dev->dev_task_attr_type != SAM_TASK_ATTR_EMULATED) {
                list_add_tail(&task->t_execute_list, &dev->execute_task_list);
                return 0;
        }
        /*
         * HEAD_OF_QUEUE attribute for received CDB, which means
         * the first task that is associated with a struct se_cmd goes to
         * head of the struct se_device->execute_task_list, and task_prev
         * after that for each subsequent task
         */
        if (task->task_se_cmd->sam_task_attr == MSG_HEAD_TAG) {
                list_add(&task->t_execute_list,
                                (task_prev != NULL) ?
                                &task_prev->t_execute_list :
                                &dev->execute_task_list);

                pr_debug("Set HEAD_OF_QUEUE for task CDB: 0x%02x"
                                " in execution queue\n",
                                task->task_se_cmd->t_task_cdb[0]);
                return 1;
        }
        /*
         * For ORDERED, SIMPLE or UNTAGGED attribute tasks once they have been
         * transitioned from Dermant -> Active state, and are added to the end
         * of the struct se_device->execute_task_list
         */
        list_add_tail(&task->t_execute_list, &dev->execute_task_list);
        return 0;
}

/*      __transport_add_task_to_execute_queue():
 *
 *      Called with se_dev_t->execute_task_lock called.
 */
static void __transport_add_task_to_execute_queue(
        struct se_task *task,
        struct se_task *task_prev,
        struct se_device *dev)
{
        int head_of_queue;

        head_of_queue = transport_add_task_check_sam_attr(task, task_prev, dev);
        atomic_inc(&dev->execute_tasks);

        if (task->t_state_active)
                return;
        /*
         * Determine if this task needs to go to HEAD_OF_QUEUE for the
         * state list as well.  Running with SAM Task Attribute emulation
         * will always return head_of_queue == 0 here
         */
        if (head_of_queue)
                list_add(&task->t_state_list, (task_prev) ?
                                &task_prev->t_state_list :
                                &dev->state_task_list);
        else
                list_add_tail(&task->t_state_list, &dev->state_task_list);

        task->t_state_active = true;

        pr_debug("Added ITT: 0x%08x task[%p] to dev: %p\n",
                task->task_se_cmd->se_tfo->get_task_tag(task->task_se_cmd),
                task, dev);
}

static void transport_add_tasks_to_state_queue(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        struct se_task *task;
        unsigned long flags;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        list_for_each_entry(task, &cmd->t_task_list, t_list) {
                spin_lock(&dev->execute_task_lock);
                if (!task->t_state_active) {
                        list_add_tail(&task->t_state_list,
                                      &dev->state_task_list);
                        task->t_state_active = true;

                        pr_debug("Added ITT: 0x%08x task[%p] to dev: %p\n",
                                task->task_se_cmd->se_tfo->get_task_tag(
                                task->task_se_cmd), task, dev);
                }
                spin_unlock(&dev->execute_task_lock);
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
}

static void transport_add_tasks_from_cmd(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        struct se_task *task, *task_prev = NULL;
        unsigned long flags;

        spin_lock_irqsave(&dev->execute_task_lock, flags);
        list_for_each_entry(task, &cmd->t_task_list, t_list) {
                if (!list_empty(&task->t_execute_list))
                        continue;
                /*
                 * __transport_add_task_to_execute_queue() handles the
                 * SAM Task Attribute emulation if enabled
                 */
                __transport_add_task_to_execute_queue(task, task_prev, dev);
                task_prev = task;
        }
        spin_unlock_irqrestore(&dev->execute_task_lock, flags);
}

void __transport_remove_task_from_execute_queue(struct se_task *task,
                struct se_device *dev)
{
        list_del_init(&task->t_execute_list);
        atomic_dec(&dev->execute_tasks);
}

static void transport_remove_task_from_execute_queue(
        struct se_task *task,
        struct se_device *dev)
{
        unsigned long flags;

        if (WARN_ON(list_empty(&task->t_execute_list)))
                return;

        spin_lock_irqsave(&dev->execute_task_lock, flags);
        __transport_remove_task_from_execute_queue(task, dev);
        spin_unlock_irqrestore(&dev->execute_task_lock, flags);
}

/*
 * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
 */

static void target_qf_do_work(struct work_struct *work)
{
        struct se_device *dev = container_of(work, struct se_device,
                                        qf_work_queue);
        LIST_HEAD(qf_cmd_list);
        struct se_cmd *cmd, *cmd_tmp;

        spin_lock_irq(&dev->qf_cmd_lock);
        list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
        spin_unlock_irq(&dev->qf_cmd_lock);

        list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
                list_del(&cmd->se_qf_node);
                atomic_dec(&dev->dev_qf_count);
                smp_mb__after_atomic_dec();

                pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
                        " context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
                        (cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
                        (cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
                        : "UNKNOWN");

                transport_add_cmd_to_queue(cmd, cmd->t_state, true);
        }
}

unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
{
        switch (cmd->data_direction) {
        case DMA_NONE:
                return "NONE";
        case DMA_FROM_DEVICE:
                return "READ";
        case DMA_TO_DEVICE:
                return "WRITE";
        case DMA_BIDIRECTIONAL:
                return "BIDI";
        default:
                break;
        }

        return "UNKNOWN";
}

void transport_dump_dev_state(
        struct se_device *dev,
        char *b,
        int *bl)
{
        *bl += sprintf(b + *bl, "Status: ");
        switch (dev->dev_status) {
        case TRANSPORT_DEVICE_ACTIVATED:
                *bl += sprintf(b + *bl, "ACTIVATED");
                break;
        case TRANSPORT_DEVICE_DEACTIVATED:
                *bl += sprintf(b + *bl, "DEACTIVATED");
                break;
        case TRANSPORT_DEVICE_SHUTDOWN:
                *bl += sprintf(b + *bl, "SHUTDOWN");
                break;
        case TRANSPORT_DEVICE_OFFLINE_ACTIVATED:
        case TRANSPORT_DEVICE_OFFLINE_DEACTIVATED:
                *bl += sprintf(b + *bl, "OFFLINE");
                break;
        default:
                *bl += sprintf(b + *bl, "UNKNOWN=%d", dev->dev_status);
                break;
        }

        *bl += sprintf(b + *bl, "  Execute/Left/Max Queue Depth: %d/%d/%d",
                atomic_read(&dev->execute_tasks), atomic_read(&dev->depth_left),
                dev->queue_depth);
        *bl += sprintf(b + *bl, "  SectorSize: %u  MaxSectors: %u\n",
                dev->se_sub_dev->se_dev_attrib.block_size, dev->se_sub_dev->se_dev_attrib.max_sectors);
        *bl += sprintf(b + *bl, "        ");
}

void transport_dump_vpd_proto_id(
        struct t10_vpd *vpd,
        unsigned char *p_buf,
        int p_buf_len)
{
        unsigned char buf[VPD_TMP_BUF_SIZE];
        int len;

        memset(buf, 0, VPD_TMP_BUF_SIZE);
        len = sprintf(buf, "T10 VPD Protocol Identifier: ");

        switch (vpd->protocol_identifier) {
        case 0x00:
                sprintf(buf+len, "Fibre Channel\n");
                break;
        case 0x10:
                sprintf(buf+len, "Parallel SCSI\n");
                break;
        case 0x20:
                sprintf(buf+len, "SSA\n");
                break;
        case 0x30:
                sprintf(buf+len, "IEEE 1394\n");
                break;
        case 0x40:
                sprintf(buf+len, "SCSI Remote Direct Memory Access"
                                " Protocol\n");
                break;
        case 0x50:
                sprintf(buf+len, "Internet SCSI (iSCSI)\n");
                break;
        case 0x60:
                sprintf(buf+len, "SAS Serial SCSI Protocol\n");
                break;
        case 0x70:
                sprintf(buf+len, "Automation/Drive Interface Transport"
                                " Protocol\n");
                break;
        case 0x80:
                sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
                break;
        default:
                sprintf(buf+len, "Unknown 0x%02x\n",
                                vpd->protocol_identifier);
                break;
        }

        if (p_buf)
                strncpy(p_buf, buf, p_buf_len);
        else
                pr_debug("%s", buf);
}

void
transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
{
        /*
         * Check if the Protocol Identifier Valid (PIV) bit is set..
         *
         * from spc3r23.pdf section 7.5.1
         */
         if (page_83[1] & 0x80) {
                vpd->protocol_identifier = (page_83[0] & 0xf0);
                vpd->protocol_identifier_set = 1;
                transport_dump_vpd_proto_id(vpd, NULL, 0);
        }
}
EXPORT_SYMBOL(transport_set_vpd_proto_id);

int transport_dump_vpd_assoc(
        struct t10_vpd *vpd,
        unsigned char *p_buf,
        int p_buf_len)
{
        unsigned char buf[VPD_TMP_BUF_SIZE];
        int ret = 0;
        int len;

        memset(buf, 0, VPD_TMP_BUF_SIZE);
        len = sprintf(buf, "T10 VPD Identifier Association: ");

        switch (vpd->association) {
        case 0x00:
                sprintf(buf+len, "addressed logical unit\n");
                break;
        case 0x10:
                sprintf(buf+len, "target port\n");
                break;
        case 0x20:
                sprintf(buf+len, "SCSI target device\n");
                break;
        default:
                sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
                ret = -EINVAL;
                break;
        }

        if (p_buf)
                strncpy(p_buf, buf, p_buf_len);
        else
                pr_debug("%s", buf);

        return ret;
}

int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
{
        /*
         * The VPD identification association..
         *
         * from spc3r23.pdf Section 7.6.3.1 Table 297
         */
        vpd->association = (page_83[1] & 0x30);
        return transport_dump_vpd_assoc(vpd, NULL, 0);
}
EXPORT_SYMBOL(transport_set_vpd_assoc);

int transport_dump_vpd_ident_type(
        struct t10_vpd *vpd,
        unsigned char *p_buf,
        int p_buf_len)
{
        unsigned char buf[VPD_TMP_BUF_SIZE];
        int ret = 0;
        int len;

        memset(buf, 0, VPD_TMP_BUF_SIZE);
        len = sprintf(buf, "T10 VPD Identifier Type: ");

        switch (vpd->device_identifier_type) {
        case 0x00:
                sprintf(buf+len, "Vendor specific\n");
                break;
        case 0x01:
                sprintf(buf+len, "T10 Vendor ID based\n");
                break;
        case 0x02:
                sprintf(buf+len, "EUI-64 based\n");
                break;
        case 0x03:
                sprintf(buf+len, "NAA\n");
                break;
        case 0x04:
                sprintf(buf+len, "Relative target port identifier\n");
                break;
        case 0x08:
                sprintf(buf+len, "SCSI name string\n");
                break;
        default:
                sprintf(buf+len, "Unsupported: 0x%02x\n",
                                vpd->device_identifier_type);
                ret = -EINVAL;
                break;
        }

        if (p_buf) {
                if (p_buf_len < strlen(buf)+1)
                        return -EINVAL;
                strncpy(p_buf, buf, p_buf_len);
        } else {
                pr_debug("%s", buf);
        }

        return ret;
}

int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
{
        /*
         * The VPD identifier type..
         *
         * from spc3r23.pdf Section 7.6.3.1 Table 298
         */
        vpd->device_identifier_type = (page_83[1] & 0x0f);
        return transport_dump_vpd_ident_type(vpd, NULL, 0);
}
EXPORT_SYMBOL(transport_set_vpd_ident_type);

int transport_dump_vpd_ident(
        struct t10_vpd *vpd,
        unsigned char *p_buf,
        int p_buf_len)
{
        unsigned char buf[VPD_TMP_BUF_SIZE];
        int ret = 0;

        memset(buf, 0, VPD_TMP_BUF_SIZE);

        switch (vpd->device_identifier_code_set) {
        case 0x01: /* Binary */
                sprintf(buf, "T10 VPD Binary Device Identifier: %s\n",
                        &vpd->device_identifier[0]);
                break;
        case 0x02: /* ASCII */
                sprintf(buf, "T10 VPD ASCII Device Identifier: %s\n",
                        &vpd->device_identifier[0]);
                break;
        case 0x03: /* UTF-8 */
                sprintf(buf, "T10 VPD UTF-8 Device Identifier: %s\n",
                        &vpd->device_identifier[0]);
                break;
        default:
                sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
                        " 0x%02x", vpd->device_identifier_code_set);
                ret = -EINVAL;
                break;
        }

        if (p_buf)
                strncpy(p_buf, buf, p_buf_len);
        else
                pr_debug("%s", buf);

        return ret;
}

int
transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
{
        static const char hex_str[] = "0123456789abcdef";
        int j = 0, i = 4; /* offset to start of the identifer */

        /*
         * The VPD Code Set (encoding)
         *
         * from spc3r23.pdf Section 7.6.3.1 Table 296
         */
        vpd->device_identifier_code_set = (page_83[0] & 0x0f);
        switch (vpd->device_identifier_code_set) {
        case 0x01: /* Binary */
                vpd->device_identifier[j++] =
                                hex_str[vpd->device_identifier_type];
                while (i < (4 + page_83[3])) {
                        vpd->device_identifier[j++] =
                                hex_str[(page_83[i] & 0xf0) >> 4];
                        vpd->device_identifier[j++] =
                                hex_str[page_83[i] & 0x0f];
                        i++;
                }
                break;
        case 0x02: /* ASCII */
        case 0x03: /* UTF-8 */
                while (i < (4 + page_83[3]))
                        vpd->device_identifier[j++] = page_83[i++];
                break;
        default:
                break;
        }

        return transport_dump_vpd_ident(vpd, NULL, 0);
}
EXPORT_SYMBOL(transport_set_vpd_ident);

static void core_setup_task_attr_emulation(struct se_device *dev)
{
        /*
         * If this device is from Target_Core_Mod/pSCSI, disable the
         * SAM Task Attribute emulation.
         *
         * This is currently not available in upsream Linux/SCSI Target
         * mode code, and is assumed to be disabled while using TCM/pSCSI.
         */
        if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV) {
                dev->dev_task_attr_type = SAM_TASK_ATTR_PASSTHROUGH;
                return;
        }

        dev->dev_task_attr_type = SAM_TASK_ATTR_EMULATED;
        pr_debug("%s: Using SAM_TASK_ATTR_EMULATED for SPC: 0x%02x"
                " device\n", dev->transport->name,
                dev->transport->get_device_rev(dev));
}

static void scsi_dump_inquiry(struct se_device *dev)
{
        struct t10_wwn *wwn = &dev->se_sub_dev->t10_wwn;
        int i, device_type;
        /*
         * Print Linux/SCSI style INQUIRY formatting to the kernel ring buffer
         */
        pr_debug("  Vendor: ");
        for (i = 0; i < 8; i++)
                if (wwn->vendor[i] >= 0x20)
                        pr_debug("%c", wwn->vendor[i]);
                else
                        pr_debug(" ");

        pr_debug("  Model: ");
        for (i = 0; i < 16; i++)
                if (wwn->model[i] >= 0x20)
                        pr_debug("%c", wwn->model[i]);
                else
                        pr_debug(" ");

        pr_debug("  Revision: ");
        for (i = 0; i < 4; i++)
                if (wwn->revision[i] >= 0x20)
                        pr_debug("%c", wwn->revision[i]);
                else
                        pr_debug(" ");

        pr_debug("\n");

        device_type = dev->transport->get_device_type(dev);
        pr_debug("  Type:   %s ", scsi_device_type(device_type));
        pr_debug("                 ANSI SCSI revision: %02x\n",
                                dev->transport->get_device_rev(dev));
}

struct se_device *transport_add_device_to_core_hba(
        struct se_hba *hba,
        struct se_subsystem_api *transport,
        struct se_subsystem_dev *se_dev,
        u32 device_flags,
        void *transport_dev,
        struct se_dev_limits *dev_limits,
        const char *inquiry_prod,
        const char *inquiry_rev)
{
        int force_pt;
        struct se_device  *dev;

        dev = kzalloc(sizeof(struct se_device), GFP_KERNEL);
        if (!dev) {
                pr_err("Unable to allocate memory for se_dev_t\n");
                return NULL;
        }

        transport_init_queue_obj(&dev->dev_queue_obj);
        dev->dev_flags          = device_flags;
        dev->dev_status         |= TRANSPORT_DEVICE_DEACTIVATED;
        dev->dev_ptr            = transport_dev;
        dev->se_hba             = hba;
        dev->se_sub_dev         = se_dev;
        dev->transport          = transport;
        INIT_LIST_HEAD(&dev->dev_list);
        INIT_LIST_HEAD(&dev->dev_sep_list);
        INIT_LIST_HEAD(&dev->dev_tmr_list);
        INIT_LIST_HEAD(&dev->execute_task_list);
        INIT_LIST_HEAD(&dev->delayed_cmd_list);
        INIT_LIST_HEAD(&dev->state_task_list);
        INIT_LIST_HEAD(&dev->qf_cmd_list);
        spin_lock_init(&dev->execute_task_lock);
        spin_lock_init(&dev->delayed_cmd_lock);
        spin_lock_init(&dev->dev_reservation_lock);
        spin_lock_init(&dev->dev_status_lock);
        spin_lock_init(&dev->se_port_lock);
        spin_lock_init(&dev->se_tmr_lock);
        spin_lock_init(&dev->qf_cmd_lock);

        dev->queue_depth        = dev_limits->queue_depth;
        atomic_set(&dev->depth_left, dev->queue_depth);
        atomic_set(&dev->dev_ordered_id, 0);

        se_dev_set_default_attribs(dev, dev_limits);

        dev->dev_index = scsi_get_new_index(SCSI_DEVICE_INDEX);
        dev->creation_time = get_jiffies_64();
        spin_lock_init(&dev->stats_lock);

        spin_lock(&hba->device_lock);
        list_add_tail(&dev->dev_list, &hba->hba_dev_list);
        hba->dev_count++;
        spin_unlock(&hba->device_lock);
        /*
         * Setup the SAM Task Attribute emulation for struct se_device
         */
        core_setup_task_attr_emulation(dev);
        /*
         * Force PR and ALUA passthrough emulation with internal object use.
         */
        force_pt = (hba->hba_flags & HBA_FLAGS_INTERNAL_USE);
        /*
         * Setup the Reservations infrastructure for struct se_device
         */
        core_setup_reservations(dev, force_pt);
        /*
         * Setup the Asymmetric Logical Unit Assignment for struct se_device
         */
        if (core_setup_alua(dev, force_pt) < 0)
                goto out;

        /*
         * Startup the struct se_device processing thread
         */
        dev->process_thread = kthread_run(transport_processing_thread, dev,
                                          "LIO_%s", dev->transport->name);
        if (IS_ERR(dev->process_thread)) {
                pr_err("Unable to create kthread: LIO_%s\n",
                        dev->transport->name);
                goto out;
        }
        /*
         * Setup work_queue for QUEUE_FULL
         */
        INIT_WORK(&dev->qf_work_queue, target_qf_do_work);
        /*
         * Preload the initial INQUIRY const values if we are doing
         * anything virtual (IBLOCK, FILEIO, RAMDISK), but not for TCM/pSCSI
         * passthrough because this is being provided by the backend LLD.
         * This is required so that transport_get_inquiry() copies these
         * originals once back into DEV_T10_WWN(dev) for the virtual device
         * setup.
         */
        if (dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV) {
                if (!inquiry_prod || !inquiry_rev) {
                        pr_err("All non TCM/pSCSI plugins require"
                                " INQUIRY consts\n");
                        goto out;
                }

                strncpy(&dev->se_sub_dev->t10_wwn.vendor[0], "LIO-ORG", 8);
                strncpy(&dev->se_sub_dev->t10_wwn.model[0], inquiry_prod, 16);
                strncpy(&dev->se_sub_dev->t10_wwn.revision[0], inquiry_rev, 4);
        }
        scsi_dump_inquiry(dev);

        return dev;
out:
        kthread_stop(dev->process_thread);

        spin_lock(&hba->device_lock);
        list_del(&dev->dev_list);
        hba->dev_count--;
        spin_unlock(&hba->device_lock);

        se_release_vpd_for_dev(dev);

        kfree(dev);

        return NULL;
}
EXPORT_SYMBOL(transport_add_device_to_core_hba);

/*      transport_generic_prepare_cdb():
 *
 *      Since the Initiator sees iSCSI devices as LUNs,  the SCSI CDB will
 *      contain the iSCSI LUN in bits 7-5 of byte 1 as per SAM-2.
 *      The point of this is since we are mapping iSCSI LUNs to
 *      SCSI Target IDs having a non-zero LUN in the CDB will throw the
 *      devices and HBAs for a loop.
 */
static inline void transport_generic_prepare_cdb(
        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 */
                break;
        default:
                cdb[1] &= 0x1f; /* clear logical unit number */
                break;
        }
}

static struct se_task *
transport_generic_get_task(struct se_cmd *cmd,
                enum dma_data_direction data_direction)
{
        struct se_task *task;
        struct se_device *dev = cmd->se_dev;

        task = dev->transport->alloc_task(cmd->t_task_cdb);
        if (!task) {
                pr_err("Unable to allocate struct se_task\n");
                return NULL;
        }

        INIT_LIST_HEAD(&task->t_list);
        INIT_LIST_HEAD(&task->t_execute_list);
        INIT_LIST_HEAD(&task->t_state_list);
        init_completion(&task->task_stop_comp);
        task->task_se_cmd = cmd;
        task->task_data_direction = data_direction;

        return task;
}

static int transport_generic_cmd_sequencer(struct se_cmd *, unsigned char *);

/*
 * Used by fabric modules containing a local struct se_cmd within their
 * fabric dependent per I/O descriptor.
 */
void transport_init_se_cmd(
        struct se_cmd *cmd,
        struct target_core_fabric_ops *tfo,
        struct se_session *se_sess,
        u32 data_length,
        int data_direction,
        int task_attr,
        unsigned char *sense_buffer)
{
        INIT_LIST_HEAD(&cmd->se_lun_node);
        INIT_LIST_HEAD(&cmd->se_delayed_node);
        INIT_LIST_HEAD(&cmd->se_qf_node);
        INIT_LIST_HEAD(&cmd->se_queue_node);
        INIT_LIST_HEAD(&cmd->se_cmd_list);
        INIT_LIST_HEAD(&cmd->t_task_list);
        init_completion(&cmd->transport_lun_fe_stop_comp);
        init_completion(&cmd->transport_lun_stop_comp);
        init_completion(&cmd->t_transport_stop_comp);
        init_completion(&cmd->cmd_wait_comp);
        spin_lock_init(&cmd->t_state_lock);
        atomic_set(&cmd->transport_dev_active, 1);

        cmd->se_tfo = tfo;
        cmd->se_sess = se_sess;
        cmd->data_length = data_length;
        cmd->data_direction = data_direction;
        cmd->sam_task_attr = task_attr;
        cmd->sense_buffer = sense_buffer;
}
EXPORT_SYMBOL(transport_init_se_cmd);

static int transport_check_alloc_task_attr(struct se_cmd *cmd)
{
        /*
         * Check if SAM Task Attribute emulation is enabled for this
         * struct se_device storage object
         */
        if (cmd->se_dev->dev_task_attr_type != SAM_TASK_ATTR_EMULATED)
                return 0;

        if (cmd->sam_task_attr == MSG_ACA_TAG) {
                pr_debug("SAM Task Attribute ACA"
                        " emulation is not supported\n");
                return -EINVAL;
        }
        /*
         * Used to determine when ORDERED commands should go from
         * Dormant to Active status.
         */
        cmd->se_ordered_id = atomic_inc_return(&cmd->se_dev->dev_ordered_id);
        smp_mb__after_atomic_inc();
        pr_debug("Allocated se_ordered_id: %u for Task Attr: 0x%02x on %s\n",
                        cmd->se_ordered_id, cmd->sam_task_attr,
                        cmd->se_dev->transport->name);
        return 0;
}

/*      transport_generic_allocate_tasks():
 *
 *      Called from fabric RX Thread.
 */
int transport_generic_allocate_tasks(
        struct se_cmd *cmd,
        unsigned char *cdb)
{
        int ret;

        transport_generic_prepare_cdb(cdb);
        /*
         * Ensure that the received CDB is less than the max (252 + 8) bytes
         * for VARIABLE_LENGTH_CMD
         */
        if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
                pr_err("Received SCSI CDB with command_size: %d that"
                        " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
                        scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
                cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
                return -EINVAL;
        }
        /*
         * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
         * allocate the additional extended CDB buffer now..  Otherwise
         * setup the pointer from __t_task_cdb to t_task_cdb.
         */
        if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
                cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
                                                GFP_KERNEL);
                if (!cmd->t_task_cdb) {
                        pr_err("Unable to allocate cmd->t_task_cdb"
                                " %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
                                scsi_command_size(cdb),
                                (unsigned long)sizeof(cmd->__t_task_cdb));
                        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        cmd->scsi_sense_reason =
                                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                        return -ENOMEM;
                }
        } else
                cmd->t_task_cdb = &cmd->__t_task_cdb[0];
        /*
         * Copy the original CDB into cmd->
         */
        memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
        /*
         * Setup the received CDB based on SCSI defined opcodes and
         * perform unit attention, persistent reservations and ALUA
         * checks for virtual device backends.  The cmd->t_task_cdb
         * pointer is expected to be setup before we reach this point.
         */
        ret = transport_generic_cmd_sequencer(cmd, cdb);
        if (ret < 0)
                return ret;
        /*
         * Check for SAM Task Attribute Emulation
         */
        if (transport_check_alloc_task_attr(cmd) < 0) {
                cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
                return -EINVAL;
        }
        spin_lock(&cmd->se_lun->lun_sep_lock);
        if (cmd->se_lun->lun_sep)
                cmd->se_lun->lun_sep->sep_stats.cmd_pdus++;
        spin_unlock(&cmd->se_lun->lun_sep_lock);
        return 0;
}
EXPORT_SYMBOL(transport_generic_allocate_tasks);

/*
 * Used by fabric module frontends to queue tasks directly.
 * Many only be used from process context only
 */
int transport_handle_cdb_direct(
        struct se_cmd *cmd)
{
        int ret;

        if (!cmd->se_lun) {
                dump_stack();
                pr_err("cmd->se_lun is NULL\n");
                return -EINVAL;
        }
        if (in_interrupt()) {
                dump_stack();
                pr_err("transport_generic_handle_cdb cannot be called"
                                " from interrupt context\n");
                return -EINVAL;
        }
        /*
         * Set TRANSPORT_NEW_CMD state and cmd->t_transport_active=1 following
         * transport_generic_handle_cdb*() -> transport_add_cmd_to_queue()
         * in existing usage to ensure that outstanding descriptors are handled
         * correctly during shutdown via transport_wait_for_tasks()
         *
         * Also, we don't take cmd->t_state_lock here as we only expect
         * this to be called for initial descriptor submission.
         */
        cmd->t_state = TRANSPORT_NEW_CMD;
        atomic_set(&cmd->t_transport_active, 1);
        /*
         * transport_generic_new_cmd() is already handling QUEUE_FULL,
         * so follow TRANSPORT_NEW_CMD processing thread context usage
         * and call transport_generic_request_failure() if necessary..
         */
        ret = transport_generic_new_cmd(cmd);
        if (ret < 0)
                transport_generic_request_failure(cmd);

        return 0;
}
EXPORT_SYMBOL(transport_handle_cdb_direct);

/*
 * Used by fabric module frontends defining a TFO->new_cmd_map() caller
 * to  queue up a newly setup se_cmd w/ TRANSPORT_NEW_CMD_MAP in order to
 * complete setup in TCM process context w/ TFO->new_cmd_map().
 */
int transport_generic_handle_cdb_map(
        struct se_cmd *cmd)
{
        if (!cmd->se_lun) {
                dump_stack();
                pr_err("cmd->se_lun is NULL\n");
                return -EINVAL;
        }

        transport_add_cmd_to_queue(cmd, TRANSPORT_NEW_CMD_MAP, false);
        return 0;
}
EXPORT_SYMBOL(transport_generic_handle_cdb_map);

/*      transport_generic_handle_data():
 *
 *
 */
int transport_generic_handle_data(
        struct se_cmd *cmd)
{
        /*
         * For the software fabric case, then we assume the nexus is being
         * failed/shutdown when signals are pending from the kthread context
         * caller, so we return a failure.  For the HW target mode case running
         * in interrupt code, the signal_pending() check is skipped.
         */
        if (!in_interrupt() && signal_pending(current))
                return -EPERM;
        /*
         * If the received CDB has aleady been ABORTED by the generic
         * target engine, we now call transport_check_aborted_status()
         * to queue any delated TASK_ABORTED status for the received CDB to the
         * fabric module as we are expecting no further incoming DATA OUT
         * sequences at this point.
         */
        if (transport_check_aborted_status(cmd, 1) != 0)
                return 0;

        transport_add_cmd_to_queue(cmd, TRANSPORT_PROCESS_WRITE, false);
        return 0;
}
EXPORT_SYMBOL(transport_generic_handle_data);

/*      transport_generic_handle_tmr():
 *
 *
 */
int transport_generic_handle_tmr(
        struct se_cmd *cmd)
{
        transport_add_cmd_to_queue(cmd, TRANSPORT_PROCESS_TMR, false);
        return 0;
}
EXPORT_SYMBOL(transport_generic_handle_tmr);

/*
 * If the task is active, request it to be stopped and sleep until it
 * has completed.
 */
bool target_stop_task(struct se_task *task, unsigned long *flags)
{
        struct se_cmd *cmd = task->task_se_cmd;
        bool was_active = false;

        if (task->task_flags & TF_ACTIVE) {
                task->task_flags |= TF_REQUEST_STOP;
                spin_unlock_irqrestore(&cmd->t_state_lock, *flags);

                pr_debug("Task %p waiting to complete\n", task);
                wait_for_completion(&task->task_stop_comp);
                pr_debug("Task %p stopped successfully\n", task);

                spin_lock_irqsave(&cmd->t_state_lock, *flags);
                atomic_dec(&cmd->t_task_cdbs_left);
                task->task_flags &= ~(TF_ACTIVE | TF_REQUEST_STOP);
                was_active = true;
        }

        return was_active;
}

static int transport_stop_tasks_for_cmd(struct se_cmd *cmd)
{
        struct se_task *task, *task_tmp;
        unsigned long flags;
        int ret = 0;

        pr_debug("ITT[0x%08x] - Stopping tasks\n",
                cmd->se_tfo->get_task_tag(cmd));

        /*
         * No tasks remain in the execution queue
         */
        spin_lock_irqsave(&cmd->t_state_lock, flags);
        list_for_each_entry_safe(task, task_tmp,
                                &cmd->t_task_list, t_list) {
                pr_debug("Processing task %p\n", task);
                /*
                 * If the struct se_task has not been sent and is not active,
                 * remove the struct se_task from the execution queue.
                 */
                if (!(task->task_flags & (TF_ACTIVE | TF_SENT))) {
                        spin_unlock_irqrestore(&cmd->t_state_lock,
                                        flags);
                        transport_remove_task_from_execute_queue(task,
                                        cmd->se_dev);

                        pr_debug("Task %p removed from execute queue\n", task);
                        spin_lock_irqsave(&cmd->t_state_lock, flags);
                        continue;
                }

                if (!target_stop_task(task, &flags)) {
                        pr_debug("Task %p - did nothing\n", task);
                        ret++;
                }
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        return ret;
}

/*
 * Handle SAM-esque emulation for generic transport request failures.
 */
static void transport_generic_request_failure(struct se_cmd *cmd)
{
        int ret = 0;

        pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08x"
                " CDB: 0x%02x\n", cmd, cmd->se_tfo->get_task_tag(cmd),
                cmd->t_task_cdb[0]);
        pr_debug("-----[ i_state: %d t_state: %d scsi_sense_reason: %d\n",
                cmd->se_tfo->get_cmd_state(cmd),
                cmd->t_state, cmd->scsi_sense_reason);
        pr_debug("-----[ t_tasks: %d t_task_cdbs_left: %d"
                " t_task_cdbs_sent: %d t_task_cdbs_ex_left: %d --"
                " t_transport_active: %d t_transport_stop: %d"
                " t_transport_sent: %d\n", cmd->t_task_list_num,
                atomic_read(&cmd->t_task_cdbs_left),
                atomic_read(&cmd->t_task_cdbs_sent),
                atomic_read(&cmd->t_task_cdbs_ex_left),
                atomic_read(&cmd->t_transport_active),
                atomic_read(&cmd->t_transport_stop),
                atomic_read(&cmd->t_transport_sent));

        /*
         * For SAM Task Attribute emulation for failed struct se_cmd
         */
        if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                transport_complete_task_attr(cmd);

        switch (cmd->scsi_sense_reason) {
        case TCM_NON_EXISTENT_LUN:
        case TCM_UNSUPPORTED_SCSI_OPCODE:
        case TCM_INVALID_CDB_FIELD:
        case TCM_INVALID_PARAMETER_LIST:
        case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
        case TCM_UNKNOWN_MODE_PAGE:
        case TCM_WRITE_PROTECTED:
        case TCM_CHECK_CONDITION_ABORT_CMD:
        case TCM_CHECK_CONDITION_UNIT_ATTENTION:
        case TCM_CHECK_CONDITION_NOT_READY:
                break;
        case TCM_RESERVATION_CONFLICT:
                /*
                 * No SENSE Data payload for this case, set SCSI Status
                 * and queue the response to $FABRIC_MOD.
                 *
                 * Uses linux/include/scsi/scsi.h SAM status codes defs
                 */
                cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
                /*
                 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
                 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
                 * CONFLICT STATUS.
                 *
                 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
                 */
                if (cmd->se_sess &&
                    cmd->se_dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl == 2)
                        core_scsi3_ua_allocate(cmd->se_sess->se_node_acl,
                                cmd->orig_fe_lun, 0x2C,
                                ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);

                ret = cmd->se_tfo->queue_status(cmd);
                if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                goto check_stop;
        default:
                pr_err("Unknown transport error for CDB 0x%02x: %d\n",
                        cmd->t_task_cdb[0], cmd->scsi_sense_reason);
                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
                break;
        }
        /*
         * If a fabric does not define a cmd->se_tfo->new_cmd_map caller,
         * make the call to transport_send_check_condition_and_sense()
         * directly.  Otherwise expect the fabric to make the call to
         * transport_send_check_condition_and_sense() after handling
         * possible unsoliticied write data payloads.
         */
        ret = transport_send_check_condition_and_sense(cmd,
                        cmd->scsi_sense_reason, 0);
        if (ret == -EAGAIN || ret == -ENOMEM)
                goto queue_full;

check_stop:
        transport_lun_remove_cmd(cmd);
        if (!transport_cmd_check_stop_to_fabric(cmd))
                ;
        return;

queue_full:
        cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
        transport_handle_queue_full(cmd, cmd->se_dev);
}

static inline u32 transport_lba_21(unsigned char *cdb)
{
        return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
}

static inline u32 transport_lba_32(unsigned char *cdb)
{
        return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
}

static inline unsigned long long transport_lba_64(unsigned char *cdb)
{
        unsigned int __v1, __v2;

        __v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
        __v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];

        return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
}

/*
 * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
 */
static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
{
        unsigned int __v1, __v2;

        __v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
        __v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];

        return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
}

static void transport_set_supported_SAM_opcode(struct se_cmd *se_cmd)
{
        unsigned long flags;

        spin_lock_irqsave(&se_cmd->t_state_lock, flags);
        se_cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
        spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
}

static inline int transport_tcq_window_closed(struct se_device *dev)
{
        if (dev->dev_tcq_window_closed++ <
                        PYX_TRANSPORT_WINDOW_CLOSED_THRESHOLD) {
                msleep(PYX_TRANSPORT_WINDOW_CLOSED_WAIT_SHORT);
        } else
                msleep(PYX_TRANSPORT_WINDOW_CLOSED_WAIT_LONG);

        wake_up_interruptible(&dev->dev_queue_obj.thread_wq);
        return 0;
}

/*
 * Called from Fabric Module context from transport_execute_tasks()
 *
 * The return of this function determins if the tasks from struct se_cmd
 * get added to the execution queue in transport_execute_tasks(),
 * or are added to the delayed or ordered lists here.
 */
static inline int transport_execute_task_attr(struct se_cmd *cmd)
{
        if (cmd->se_dev->dev_task_attr_type != SAM_TASK_ATTR_EMULATED)
                return 1;
        /*
         * Check for the existence of HEAD_OF_QUEUE, and if true return 1
         * to allow the passed struct se_cmd list of tasks to the front of the list.
         */
         if (cmd->sam_task_attr == MSG_HEAD_TAG) {
                pr_debug("Added HEAD_OF_QUEUE for CDB:"
                        " 0x%02x, se_ordered_id: %u\n",
                        cmd->t_task_cdb[0],
                        cmd->se_ordered_id);
                return 1;
        } else if (cmd->sam_task_attr == MSG_ORDERED_TAG) {
                atomic_inc(&cmd->se_dev->dev_ordered_sync);
                smp_mb__after_atomic_inc();

                pr_debug("Added ORDERED for CDB: 0x%02x to ordered"
                                " list, se_ordered_id: %u\n",
                                cmd->t_task_cdb[0],
                                cmd->se_ordered_id);
                /*
                 * Add ORDERED command to tail of execution queue if
                 * no other older commands exist that need to be
                 * completed first.
                 */
                if (!atomic_read(&cmd->se_dev->simple_cmds))
                        return 1;
        } else {
                /*
                 * For SIMPLE and UNTAGGED Task Attribute commands
                 */
                atomic_inc(&cmd->se_dev->simple_cmds);
                smp_mb__after_atomic_inc();
        }
        /*
         * Otherwise if one or more outstanding ORDERED task attribute exist,
         * add the dormant task(s) built for the passed struct se_cmd to the
         * execution queue and become in Active state for this struct se_device.
         */
        if (atomic_read(&cmd->se_dev->dev_ordered_sync) != 0) {
                /*
                 * Otherwise, add cmd w/ tasks to delayed cmd queue that
                 * will be drained upon completion of HEAD_OF_QUEUE task.
                 */
                spin_lock(&cmd->se_dev->delayed_cmd_lock);
                cmd->se_cmd_flags |= SCF_DELAYED_CMD_FROM_SAM_ATTR;
                list_add_tail(&cmd->se_delayed_node,
                                &cmd->se_dev->delayed_cmd_list);
                spin_unlock(&cmd->se_dev->delayed_cmd_lock);

                pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to"
                        " delayed CMD list, se_ordered_id: %u\n",
                        cmd->t_task_cdb[0], cmd->sam_task_attr,
                        cmd->se_ordered_id);
                /*
                 * Return zero to let transport_execute_tasks() know
                 * not to add the delayed tasks to the execution list.
                 */
                return 0;
        }
        /*
         * Otherwise, no ORDERED task attributes exist..
         */
        return 1;
}

/*
 * Called from fabric module context in transport_generic_new_cmd() and
 * transport_generic_process_write()
 */
static int transport_execute_tasks(struct se_cmd *cmd)
{
        int add_tasks;

        if (se_dev_check_online(cmd->se_dev) != 0) {
                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                transport_generic_request_failure(cmd);
                return 0;
        }

        /*
         * Call transport_cmd_check_stop() to see if a fabric exception
         * has occurred that prevents execution.
         */
        if (!transport_cmd_check_stop(cmd, 0, TRANSPORT_PROCESSING)) {
                /*
                 * Check for SAM Task Attribute emulation and HEAD_OF_QUEUE
                 * attribute for the tasks of the received struct se_cmd CDB
                 */
                add_tasks = transport_execute_task_attr(cmd);
                if (!add_tasks)
                        goto execute_tasks;
                /*
                 * This calls transport_add_tasks_from_cmd() to handle
                 * HEAD_OF_QUEUE ordering for SAM Task Attribute emulation
                 * (if enabled) in __transport_add_task_to_execute_queue() and
                 * transport_add_task_check_sam_attr().
                 */
                transport_add_tasks_from_cmd(cmd);
        }
        /*
         * Kick the execution queue for the cmd associated struct se_device
         * storage object.
         */
execute_tasks:
        __transport_execute_tasks(cmd->se_dev);
        return 0;
}

/*
 * Called to check struct se_device tcq depth window, and once open pull struct se_task
 * from struct se_device->execute_task_list and
 *
 * Called from transport_processing_thread()
 */
static int __transport_execute_tasks(struct se_device *dev)
{
        int error;
        struct se_cmd *cmd = NULL;
        struct se_task *task = NULL;
        unsigned long flags;

        /*
         * Check if there is enough room in the device and HBA queue to send
         * struct se_tasks to the selected transport.
         */
check_depth:
        if (!atomic_read(&dev->depth_left))
                return transport_tcq_window_closed(dev);

        dev->dev_tcq_window_closed = 0;

        spin_lock_irq(&dev->execute_task_lock);
        if (list_empty(&dev->execute_task_list)) {
                spin_unlock_irq(&dev->execute_task_lock);
                return 0;
        }
        task = list_first_entry(&dev->execute_task_list,
                                struct se_task, t_execute_list);
        __transport_remove_task_from_execute_queue(task, dev);
        spin_unlock_irq(&dev->execute_task_lock);

        atomic_dec(&dev->depth_left);

        cmd = task->task_se_cmd;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        task->task_flags |= (TF_ACTIVE | TF_SENT);
        atomic_inc(&cmd->t_task_cdbs_sent);

        if (atomic_read(&cmd->t_task_cdbs_sent) ==
            cmd->t_task_list_num)
                atomic_set(&cmd->t_transport_sent, 1);

        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        if (cmd->execute_task)
                error = cmd->execute_task(task);
        else
                error = dev->transport->do_task(task);
        if (error != 0) {
                spin_lock_irqsave(&cmd->t_state_lock, flags);
                task->task_flags &= ~TF_ACTIVE;
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                atomic_set(&cmd->t_transport_sent, 0);
                transport_stop_tasks_for_cmd(cmd);
                atomic_inc(&dev->depth_left);
                transport_generic_request_failure(cmd);
        }

        goto check_depth;

        return 0;
}

static inline u32 transport_get_sectors_6(
        unsigned char *cdb,
        struct se_cmd *cmd,
        int *ret)
{
        struct se_device *dev = cmd->se_dev;

        /*
         * Assume TYPE_DISK for non struct se_device objects.
         * Use 8-bit sector value.
         */
        if (!dev)
                goto type_disk;

        /*
         * Use 24-bit allocation length for TYPE_TAPE.
         */
        if (dev->transport->get_device_type(dev) == TYPE_TAPE)
                return (u32)(cdb[2] << 16) + (cdb[3] << 8) + cdb[4];

        /*
         * Everything else assume TYPE_DISK Sector CDB location.
         * Use 8-bit sector value.  SBC-3 says:
         *
         *   A TRANSFER LENGTH field set to zero specifies that 256
         *   logical blocks shall be written.  Any other value
         *   specifies the number of logical blocks that shall be
         *   written.
         */
type_disk:
        return cdb[4] ? : 256;
}

static inline u32 transport_get_sectors_10(
        unsigned char *cdb,
        struct se_cmd *cmd,
        int *ret)
{
        struct se_device *dev = cmd->se_dev;

        /*
         * Assume TYPE_DISK for non struct se_device objects.
         * Use 16-bit sector value.
         */
        if (!dev)
                goto type_disk;

        /*
         * XXX_10 is not defined in SSC, throw an exception
         */
        if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
                *ret = -EINVAL;
                return 0;
        }

        /*
         * Everything else assume TYPE_DISK Sector CDB location.
         * Use 16-bit sector value.
         */
type_disk:
        return (u32)(cdb[7] << 8) + cdb[8];
}

static inline u32 transport_get_sectors_12(
        unsigned char *cdb,
        struct se_cmd *cmd,
        int *ret)
{
        struct se_device *dev = cmd->se_dev;

        /*
         * Assume TYPE_DISK for non struct se_device objects.
         * Use 32-bit sector value.
         */
        if (!dev)
                goto type_disk;

        /*
         * XXX_12 is not defined in SSC, throw an exception
         */
        if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
                *ret = -EINVAL;
                return 0;
        }

        /*
         * Everything else assume TYPE_DISK Sector CDB location.
         * Use 32-bit sector value.
         */
type_disk:
        return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
}

static inline u32 transport_get_sectors_16(
        unsigned char *cdb,
        struct se_cmd *cmd,
        int *ret)
{
        struct se_device *dev = cmd->se_dev;

        /*
         * Assume TYPE_DISK for non struct se_device objects.
         * Use 32-bit sector value.
         */
        if (!dev)
                goto type_disk;

        /*
         * Use 24-bit allocation length for TYPE_TAPE.
         */
        if (dev->transport->get_device_type(dev) == TYPE_TAPE)
                return (u32)(cdb[12] << 16) + (cdb[13] << 8) + cdb[14];

type_disk:
        return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
                    (cdb[12] << 8) + cdb[13];
}

/*
 * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
 */
static inline u32 transport_get_sectors_32(
        unsigned char *cdb,
        struct se_cmd *cmd,
        int *ret)
{
        /*
         * Assume TYPE_DISK for non struct se_device objects.
         * Use 32-bit sector value.
         */
        return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
                    (cdb[30] << 8) + cdb[31];

}

static inline u32 transport_get_size(
        u32 sectors,
        unsigned char *cdb,
        struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;

        if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
                if (cdb[1] & 1) { /* sectors */
                        return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
                } else /* bytes */
                        return sectors;
        }
#if 0
        pr_debug("Returning block_size: %u, sectors: %u == %u for"
                        " %s object\n", dev->se_sub_dev->se_dev_attrib.block_size, sectors,
                        dev->se_sub_dev->se_dev_attrib.block_size * sectors,
                        dev->transport->name);
#endif
        return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
}

static void transport_xor_callback(struct se_cmd *cmd)
{
        unsigned char *buf, *addr;
        struct scatterlist *sg;
        unsigned int offset;
        int i;
        int count;
        /*
         * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
         *
         * 1) read the specified logical block(s);
         * 2) transfer logical blocks from the data-out buffer;
         * 3) XOR the logical blocks transferred from the data-out buffer with
         *    the logical blocks read, storing the resulting XOR data in a buffer;
         * 4) if the DISABLE WRITE bit is set to zero, then write the logical
         *    blocks transferred from the data-out buffer; and
         * 5) transfer the resulting XOR data to the data-in buffer.
         */
        buf = kmalloc(cmd->data_length, GFP_KERNEL);
        if (!buf) {
                pr_err("Unable to allocate xor_callback buf\n");
                return;
        }
        /*
         * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
         * into the locally allocated *buf
         */
        sg_copy_to_buffer(cmd->t_data_sg,
                          cmd->t_data_nents,
                          buf,
                          cmd->data_length);

        /*
         * Now perform the XOR against the BIDI read memory located at
         * cmd->t_mem_bidi_list
         */

        offset = 0;
        for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
                addr = kmap_atomic(sg_page(sg), KM_USER0);
                if (!addr)
                        goto out;

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

                offset += sg->length;
                kunmap_atomic(addr, KM_USER0);
        }

out:
        kfree(buf);
}

/*
 * Used to obtain Sense Data from underlying Linux/SCSI struct scsi_cmnd
 */
static int transport_get_sense_data(struct se_cmd *cmd)
{
        unsigned char *buffer = cmd->sense_buffer, *sense_buffer = NULL;
        struct se_device *dev = cmd->se_dev;
        struct se_task *task = NULL, *task_tmp;
        unsigned long flags;
        u32 offset = 0;

        WARN_ON(!cmd->se_lun);

        if (!dev)
                return 0;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return 0;
        }

        list_for_each_entry_safe(task, task_tmp,
                                &cmd->t_task_list, t_list) {
                if (!(task->task_flags & TF_HAS_SENSE))
                        continue;

                if (!dev->transport->get_sense_buffer) {
                        pr_err("dev->transport->get_sense_buffer"
                                        " is NULL\n");
                        continue;
                }

                sense_buffer = dev->transport->get_sense_buffer(task);
                if (!sense_buffer) {
                        pr_err("ITT[0x%08x]_TASK[%p]: Unable to locate"
                                " sense buffer for task with sense\n",
                                cmd->se_tfo->get_task_tag(cmd), task);
                        continue;
                }
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);

                offset = cmd->se_tfo->set_fabric_sense_len(cmd,
                                TRANSPORT_SENSE_BUFFER);

                memcpy(&buffer[offset], sense_buffer,
                                TRANSPORT_SENSE_BUFFER);
                cmd->scsi_status = task->task_scsi_status;
                /* Automatically padded */
                cmd->scsi_sense_length =
                                (TRANSPORT_SENSE_BUFFER + offset);

                pr_debug("HBA_[%u]_PLUG[%s]: Set SAM STATUS: 0x%02x"
                                " and sense\n",
                        dev->se_hba->hba_id, dev->transport->name,
                                cmd->scsi_status);
                return 0;
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        return -1;
}

static inline long long transport_dev_end_lba(struct se_device *dev)
{
        return dev->transport->get_blocks(dev) + 1;
}

static int transport_cmd_get_valid_sectors(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        u32 sectors;

        if (dev->transport->get_device_type(dev) != TYPE_DISK)
                return 0;

        sectors = (cmd->data_length / dev->se_sub_dev->se_dev_attrib.block_size);

        if ((cmd->t_task_lba + sectors) > transport_dev_end_lba(dev)) {
                pr_err("LBA: %llu Sectors: %u exceeds"
                        " transport_dev_end_lba(): %llu\n",
                        cmd->t_task_lba, sectors,
                        transport_dev_end_lba(dev));
                return -EINVAL;
        }

        return 0;
}

static int target_check_write_same_discard(unsigned char *flags, struct se_device *dev)
{
        /*
         * Determine if the received WRITE_SAME is used to for direct
         * passthrough into Linux/SCSI with struct request via TCM/pSCSI
         * or we are signaling the use of internal WRITE_SAME + UNMAP=1
         * emulation for -> Linux/BLOCK disbard with TCM/IBLOCK code.
         */
        int passthrough = (dev->transport->transport_type ==
                                TRANSPORT_PLUGIN_PHBA_PDEV);

        if (!passthrough) {
                if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
                        pr_err("WRITE_SAME PBDATA and LBDATA"
                                " bits not supported for Block Discard"
                                " Emulation\n");
                        return -ENOSYS;
                }
                /*
                 * Currently for the emulated case we only accept
                 * tpws with the UNMAP=1 bit set.
                 */
                if (!(flags[0] & 0x08)) {
                        pr_err("WRITE_SAME w/o UNMAP bit not"
                                " supported for Block Discard Emulation\n");
                        return -ENOSYS;
                }
        }

        return 0;
}

/*      transport_generic_cmd_sequencer():
 *
 *      Generic Command Sequencer that should work for most DAS transport
 *      drivers.
 *
 *      Called from transport_generic_allocate_tasks() in the $FABRIC_MOD
 *      RX Thread.
 *
 *      FIXME: Need to support other SCSI OPCODES where as well.
 */
static int transport_generic_cmd_sequencer(
        struct se_cmd *cmd,
        unsigned char *cdb)
{
        struct se_device *dev = cmd->se_dev;
        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        int ret = 0, sector_ret = 0, passthrough;
        u32 sectors = 0, size = 0, pr_reg_type = 0;
        u16 service_action;
        u8 alua_ascq = 0;
        /*
         * Check for an existing UNIT ATTENTION condition
         */
        if (core_scsi3_ua_check(cmd, cdb) < 0) {
                cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                cmd->scsi_sense_reason = TCM_CHECK_CONDITION_UNIT_ATTENTION;
                return -EINVAL;
        }
        /*
         * Check status of Asymmetric Logical Unit Assignment port
         */
        ret = su_dev->t10_alua.alua_state_check(cmd, cdb, &alua_ascq);
        if (ret != 0) {
                /*
                 * Set SCSI additional sense code (ASC) to 'LUN Not Accessible';
                 * The ALUA additional sense code qualifier (ASCQ) is determined
                 * by the ALUA primary or secondary access state..
                 */
                if (ret > 0) {
#if 0
                        pr_debug("[%s]: ALUA TG Port not available,"
                                " SenseKey: NOT_READY, ASC/ASCQ: 0x04/0x%02x\n",
                                cmd->se_tfo->get_fabric_name(), alua_ascq);
#endif
                        transport_set_sense_codes(cmd, 0x04, alua_ascq);
                        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        cmd->scsi_sense_reason = TCM_CHECK_CONDITION_NOT_READY;
                        return -EINVAL;
                }
                goto out_invalid_cdb_field;
        }
        /*
         * Check status for SPC-3 Persistent Reservations
         */
        if (su_dev->t10_pr.pr_ops.t10_reservation_check(cmd, &pr_reg_type) != 0) {
                if (su_dev->t10_pr.pr_ops.t10_seq_non_holder(
                                        cmd, cdb, pr_reg_type) != 0) {
                        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        cmd->se_cmd_flags |= SCF_SCSI_RESERVATION_CONFLICT;
                        cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
                        return -EBUSY;
                }
                /*
                 * This means the CDB is allowed for the SCSI Initiator port
                 * when said port is *NOT* holding the legacy SPC-2 or
                 * SPC-3 Persistent Reservation.
                 */
        }

        /*
         * If we operate in passthrough mode we skip most CDB emulation and
         * instead hand the commands down to the physical SCSI device.
         */
        passthrough =
                (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV);

        switch (cdb[0]) {
        case READ_6:
                sectors = transport_get_sectors_6(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_21(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case READ_10:
                sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_32(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case READ_12:
                sectors = transport_get_sectors_12(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_32(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case READ_16:
                sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_64(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case WRITE_6:
                sectors = transport_get_sectors_6(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_21(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case WRITE_10:
                sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_32(cdb);
                if (cdb[1] & 0x8)
                        cmd->se_cmd_flags |= SCF_FUA;
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case WRITE_12:
                sectors = transport_get_sectors_12(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_32(cdb);
                if (cdb[1] & 0x8)
                        cmd->se_cmd_flags |= SCF_FUA;
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case WRITE_16:
                sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_64(cdb);
                if (cdb[1] & 0x8)
                        cmd->se_cmd_flags |= SCF_FUA;
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;
                break;
        case XDWRITEREAD_10:
                if ((cmd->data_direction != DMA_TO_DEVICE) ||
                    !(cmd->se_cmd_flags & SCF_BIDI))
                        goto out_invalid_cdb_field;
                sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;
                size = transport_get_size(sectors, cdb, cmd);
                cmd->t_task_lba = transport_lba_32(cdb);
                cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;

                /*
                 * Do now allow BIDI commands for passthrough mode.
                 */
                if (passthrough)
                        goto out_unsupported_cdb;

                /*
                 * Setup BIDI XOR callback to be run after I/O completion.
                 */
                cmd->transport_complete_callback = &transport_xor_callback;
                if (cdb[1] & 0x8)
                        cmd->se_cmd_flags |= SCF_FUA;
                break;
        case VARIABLE_LENGTH_CMD:
                service_action = get_unaligned_be16(&cdb[8]);
                switch (service_action) {
                case XDWRITEREAD_32:
                        sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
                        if (sector_ret)
                                goto out_unsupported_cdb;
                        size = transport_get_size(sectors, cdb, cmd);
                        /*
                         * Use WRITE_32 and READ_32 opcodes for the emulated
                         * XDWRITE_READ_32 logic.
                         */
                        cmd->t_task_lba = transport_lba_64_ext(cdb);
                        cmd->se_cmd_flags |= SCF_SCSI_DATA_SG_IO_CDB;

                        /*
                         * Do now allow BIDI commands for passthrough mode.
                         */
                        if (passthrough)
                                goto out_unsupported_cdb;

                        /*
                         * Setup BIDI XOR callback to be run during after I/O
                         * completion.
                         */
                        cmd->transport_complete_callback = &transport_xor_callback;
                        if (cdb[1] & 0x8)
                                cmd->se_cmd_flags |= SCF_FUA;
                        break;
                case WRITE_SAME_32:
                        sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
                        if (sector_ret)
                                goto out_unsupported_cdb;

                        if (sectors)
                                size = transport_get_size(1, cdb, cmd);
                        else {
                                pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
                                       " supported\n");
                                goto out_invalid_cdb_field;
                        }

                        cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
                        cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;

                        if (target_check_write_same_discard(&cdb[10], dev) < 0)
                                goto out_invalid_cdb_field;
                        if (!passthrough)
                                cmd->execute_task = target_emulate_write_same;
                        break;
                default:
                        pr_err("VARIABLE_LENGTH_CMD service action"
                                " 0x%04x not supported\n", service_action);
                        goto out_unsupported_cdb;
                }
                break;
        case MAINTENANCE_IN:
                if (dev->transport->get_device_type(dev) != TYPE_ROM) {
                        /* MAINTENANCE_IN from SCC-2 */
                        /*
                         * Check for emulated MI_REPORT_TARGET_PGS.
                         */
                        if (cdb[1] == MI_REPORT_TARGET_PGS &&
                            su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
                                cmd->execute_task =
                                        target_emulate_report_target_port_groups;
                        }
                        size = (cdb[6] << 24) | (cdb[7] << 16) |
                               (cdb[8] << 8) | cdb[9];
                } else {
                        /* GPCMD_SEND_KEY from multi media commands */
                        size = (cdb[8] << 8) + cdb[9];
                }
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case MODE_SELECT:
                size = cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case MODE_SELECT_10:
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case MODE_SENSE:
                size = cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_modesense;
                break;
        case MODE_SENSE_10:
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_modesense;
                break;
        case GPCMD_READ_BUFFER_CAPACITY:
        case GPCMD_SEND_OPC:
        case LOG_SELECT:
        case LOG_SENSE:
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case READ_BLOCK_LIMITS:
                size = READ_BLOCK_LEN;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case GPCMD_GET_CONFIGURATION:
        case GPCMD_READ_FORMAT_CAPACITIES:
        case GPCMD_READ_DISC_INFO:
        case GPCMD_READ_TRACK_RZONE_INFO:
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case PERSISTENT_RESERVE_IN:
                if (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS)
                        cmd->execute_task = target_scsi3_emulate_pr_in;
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case PERSISTENT_RESERVE_OUT:
                if (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS)
                        cmd->execute_task = target_scsi3_emulate_pr_out;
                size = (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case GPCMD_MECHANISM_STATUS:
        case GPCMD_READ_DVD_STRUCTURE:
                size = (cdb[8] << 8) + cdb[9];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case READ_POSITION:
                size = READ_POSITION_LEN;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case MAINTENANCE_OUT:
                if (dev->transport->get_device_type(dev) != TYPE_ROM) {
                        /* MAINTENANCE_OUT from SCC-2
                         *
                         * Check for emulated MO_SET_TARGET_PGS.
                         */
                        if (cdb[1] == MO_SET_TARGET_PGS &&
                            su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
                                cmd->execute_task =
                                        target_emulate_set_target_port_groups;
                        }

                        size = (cdb[6] << 24) | (cdb[7] << 16) |
                               (cdb[8] << 8) | cdb[9];
                } else  {
                        /* GPCMD_REPORT_KEY from multi media commands */
                        size = (cdb[8] << 8) + cdb[9];
                }
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case INQUIRY:
                size = (cdb[3] << 8) + cdb[4];
                /*
                 * Do implict HEAD_OF_QUEUE processing for INQUIRY.
                 * See spc4r17 section 5.3
                 */
                if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                        cmd->sam_task_attr = MSG_HEAD_TAG;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_inquiry;
                break;
        case READ_BUFFER:
                size = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case READ_CAPACITY:
                size = READ_CAP_LEN;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_readcapacity;
                break;
        case READ_MEDIA_SERIAL_NUMBER:
        case SECURITY_PROTOCOL_IN:
        case SECURITY_PROTOCOL_OUT:
                size = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case SERVICE_ACTION_IN:
                switch (cmd->t_task_cdb[1] & 0x1f) {
                case SAI_READ_CAPACITY_16:
                        if (!passthrough)
                                cmd->execute_task =
                                        target_emulate_readcapacity_16;
                        break;
                default:
                        if (passthrough)
                                break;

                        pr_err("Unsupported SA: 0x%02x\n",
                                cmd->t_task_cdb[1] & 0x1f);
                        goto out_unsupported_cdb;
                }
                /*FALLTHROUGH*/
        case ACCESS_CONTROL_IN:
        case ACCESS_CONTROL_OUT:
        case EXTENDED_COPY:
        case READ_ATTRIBUTE:
        case RECEIVE_COPY_RESULTS:
        case WRITE_ATTRIBUTE:
                size = (cdb[10] << 24) | (cdb[11] << 16) |
                       (cdb[12] << 8) | cdb[13];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case RECEIVE_DIAGNOSTIC:
        case SEND_DIAGNOSTIC:
                size = (cdb[3] << 8) | cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
/* #warning FIXME: Figure out correct GPCMD_READ_CD blocksize. */
#if 0
        case GPCMD_READ_CD:
                sectors = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
                size = (2336 * sectors);
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
#endif
        case READ_TOC:
                size = cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case REQUEST_SENSE:
                size = cdb[4];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_request_sense;
                break;
        case READ_ELEMENT_STATUS:
                size = 65536 * cdb[7] + 256 * cdb[8] + cdb[9];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case WRITE_BUFFER:
                size = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        case RESERVE:
        case RESERVE_10:
                /*
                 * The SPC-2 RESERVE does not contain a size in the SCSI CDB.
                 * Assume the passthrough or $FABRIC_MOD will tell us about it.
                 */
                if (cdb[0] == RESERVE_10)
                        size = (cdb[7] << 8) | cdb[8];
                else
                        size = cmd->data_length;

                /*
                 * Setup the legacy emulated handler for SPC-2 and
                 * >= SPC-3 compatible reservation handling (CRH=1)
                 * Otherwise, we assume the underlying SCSI logic is
                 * is running in SPC_PASSTHROUGH, and wants reservations
                 * emulation disabled.
                 */
                if (su_dev->t10_pr.res_type != SPC_PASSTHROUGH)
                        cmd->execute_task = target_scsi2_reservation_reserve;
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case RELEASE:
        case RELEASE_10:
                /*
                 * The SPC-2 RELEASE does not contain a size in the SCSI CDB.
                 * Assume the passthrough or $FABRIC_MOD will tell us about it.
                */
                if (cdb[0] == RELEASE_10)
                        size = (cdb[7] << 8) | cdb[8];
                else
                        size = cmd->data_length;

                if (su_dev->t10_pr.res_type != SPC_PASSTHROUGH)
                        cmd->execute_task = target_scsi2_reservation_release;
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case SYNCHRONIZE_CACHE:
        case 0x91: /* SYNCHRONIZE_CACHE_16: */
                /*
                 * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
                 */
                if (cdb[0] == SYNCHRONIZE_CACHE) {
                        sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
                        cmd->t_task_lba = transport_lba_32(cdb);
                } else {
                        sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
                        cmd->t_task_lba = transport_lba_64(cdb);
                }
                if (sector_ret)
                        goto out_unsupported_cdb;

                size = transport_get_size(sectors, cdb, cmd);
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;

                if (passthrough)
                        break;

                /*
                 * Check to ensure that LBA + Range does not exceed past end of
                 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
                 */
                if ((cmd->t_task_lba != 0) || (sectors != 0)) {
                        if (transport_cmd_get_valid_sectors(cmd) < 0)
                                goto out_invalid_cdb_field;
                }
                cmd->execute_task = target_emulate_synchronize_cache;
                break;
        case UNMAP:
                size = get_unaligned_be16(&cdb[7]);
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_unmap;
                break;
        case WRITE_SAME_16:
                sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;

                if (sectors)
                        size = transport_get_size(1, cdb, cmd);
                else {
                        pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
                        goto out_invalid_cdb_field;
                }

                cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;

                if (target_check_write_same_discard(&cdb[1], dev) < 0)
                        goto out_invalid_cdb_field;
                if (!passthrough)
                        cmd->execute_task = target_emulate_write_same;
                break;
        case WRITE_SAME:
                sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
                if (sector_ret)
                        goto out_unsupported_cdb;

                if (sectors)
                        size = transport_get_size(1, cdb, cmd);
                else {
                        pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
                        goto out_invalid_cdb_field;
                }

                cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                /*
                 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
                 * of byte 1 bit 3 UNMAP instead of original reserved field
                 */
                if (target_check_write_same_discard(&cdb[1], dev) < 0)
                        goto out_invalid_cdb_field;
                if (!passthrough)
                        cmd->execute_task = target_emulate_write_same;
                break;
        case ALLOW_MEDIUM_REMOVAL:
        case ERASE:
        case REZERO_UNIT:
        case SEEK_10:
        case SPACE:
        case START_STOP:
        case TEST_UNIT_READY:
        case VERIFY:
        case WRITE_FILEMARKS:
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                if (!passthrough)
                        cmd->execute_task = target_emulate_noop;
                break;
        case GPCMD_CLOSE_TRACK:
        case INITIALIZE_ELEMENT_STATUS:
        case GPCMD_LOAD_UNLOAD:
        case GPCMD_SET_SPEED:
        case MOVE_MEDIUM:
                cmd->se_cmd_flags |= SCF_SCSI_NON_DATA_CDB;
                break;
        case REPORT_LUNS:
                cmd->execute_task = target_report_luns;
                size = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
                /*
                 * Do implict HEAD_OF_QUEUE processing for REPORT_LUNS
                 * See spc4r17 section 5.3
                 */
                if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                        cmd->sam_task_attr = MSG_HEAD_TAG;
                cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;
                break;
        default:
                pr_warn("TARGET_CORE[%s]: Unsupported SCSI Opcode"
                        " 0x%02x, sending CHECK_CONDITION.\n",
                        cmd->se_tfo->get_fabric_name(), cdb[0]);
                goto out_unsupported_cdb;
        }

        if (size != cmd->data_length) {
                pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
                        " %u does not match SCSI CDB Length: %u for SAM Opcode:"
                        " 0x%02x\n", cmd->se_tfo->get_fabric_name(),
                                cmd->data_length, size, cdb[0]);

                cmd->cmd_spdtl = size;

                if (cmd->data_direction == DMA_TO_DEVICE) {
                        pr_err("Rejecting underflow/overflow"
                                        " WRITE data\n");
                        goto out_invalid_cdb_field;
                }
                /*
                 * Reject READ_* or WRITE_* with overflow/underflow for
                 * type SCF_SCSI_DATA_SG_IO_CDB.
                 */
                if (!ret && (dev->se_sub_dev->se_dev_attrib.block_size != 512))  {
                        pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
                                " CDB on non 512-byte sector setup subsystem"
                                " plugin: %s\n", dev->transport->name);
                        /* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
                        goto out_invalid_cdb_field;
                }

                if (size > cmd->data_length) {
                        cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
                        cmd->residual_count = (size - cmd->data_length);
                } else {
                        cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
                        cmd->residual_count = (cmd->data_length - size);
                }
                cmd->data_length = size;
        }

        /* reject any command that we don't have a handler for */
        if (!(passthrough || cmd->execute_task ||
             (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)))
                goto out_unsupported_cdb;

        /* Let's limit control cdbs to a page, for simplicity's sake. */
        if ((cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) &&
            size > PAGE_SIZE)
                goto out_invalid_cdb_field;

        transport_set_supported_SAM_opcode(cmd);
        return ret;

out_unsupported_cdb:
        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        return -EINVAL;
out_invalid_cdb_field:
        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
        return -EINVAL;
}

/*
 * Called from I/O completion to determine which dormant/delayed
 * and ordered cmds need to have their tasks added to the execution queue.
 */
static void transport_complete_task_attr(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        struct se_cmd *cmd_p, *cmd_tmp;
        int new_active_tasks = 0;

        if (cmd->sam_task_attr == MSG_SIMPLE_TAG) {
                atomic_dec(&dev->simple_cmds);
                smp_mb__after_atomic_dec();
                dev->dev_cur_ordered_id++;
                pr_debug("Incremented dev->dev_cur_ordered_id: %u for"
                        " SIMPLE: %u\n", dev->dev_cur_ordered_id,
                        cmd->se_ordered_id);
        } else if (cmd->sam_task_attr == MSG_HEAD_TAG) {
                dev->dev_cur_ordered_id++;
                pr_debug("Incremented dev_cur_ordered_id: %u for"
                        " HEAD_OF_QUEUE: %u\n", dev->dev_cur_ordered_id,
                        cmd->se_ordered_id);
        } else if (cmd->sam_task_attr == MSG_ORDERED_TAG) {
                atomic_dec(&dev->dev_ordered_sync);
                smp_mb__after_atomic_dec();

                dev->dev_cur_ordered_id++;
                pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED:"
                        " %u\n", dev->dev_cur_ordered_id, cmd->se_ordered_id);
        }
        /*
         * Process all commands up to the last received
         * ORDERED task attribute which requires another blocking
         * boundary
         */
        spin_lock(&dev->delayed_cmd_lock);
        list_for_each_entry_safe(cmd_p, cmd_tmp,
                        &dev->delayed_cmd_list, se_delayed_node) {

                list_del(&cmd_p->se_delayed_node);
                spin_unlock(&dev->delayed_cmd_lock);

                pr_debug("Calling add_tasks() for"
                        " cmd_p: 0x%02x Task Attr: 0x%02x"
                        " Dormant -> Active, se_ordered_id: %u\n",
                        cmd_p->t_task_cdb[0],
                        cmd_p->sam_task_attr, cmd_p->se_ordered_id);

                transport_add_tasks_from_cmd(cmd_p);
                new_active_tasks++;

                spin_lock(&dev->delayed_cmd_lock);
                if (cmd_p->sam_task_attr == MSG_ORDERED_TAG)
                        break;
        }
        spin_unlock(&dev->delayed_cmd_lock);
        /*
         * If new tasks have become active, wake up the transport thread
         * to do the processing of the Active tasks.
         */
        if (new_active_tasks != 0)
                wake_up_interruptible(&dev->dev_queue_obj.thread_wq);
}

static void transport_complete_qf(struct se_cmd *cmd)
{
        int ret = 0;

        if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                transport_complete_task_attr(cmd);

        if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
                ret = cmd->se_tfo->queue_status(cmd);
                if (ret)
                        goto out;
        }

        switch (cmd->data_direction) {
        case DMA_FROM_DEVICE:
                ret = cmd->se_tfo->queue_data_in(cmd);
                break;
        case DMA_TO_DEVICE:
                if (cmd->t_bidi_data_sg) {
                        ret = cmd->se_tfo->queue_data_in(cmd);
                        if (ret < 0)
                                break;
                }
                /* Fall through for DMA_TO_DEVICE */
        case DMA_NONE:
                ret = cmd->se_tfo->queue_status(cmd);
                break;
        default:
                break;
        }

out:
        if (ret < 0) {
                transport_handle_queue_full(cmd, cmd->se_dev);
                return;
        }
        transport_lun_remove_cmd(cmd);
        transport_cmd_check_stop_to_fabric(cmd);
}

static void transport_handle_queue_full(
        struct se_cmd *cmd,
        struct se_device *dev)
{
        spin_lock_irq(&dev->qf_cmd_lock);
        list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
        atomic_inc(&dev->dev_qf_count);
        smp_mb__after_atomic_inc();
        spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);

        schedule_work(&cmd->se_dev->qf_work_queue);
}

static void target_complete_ok_work(struct work_struct *work)
{
        struct se_cmd *cmd = container_of(work, struct se_cmd, work);
        int reason = 0, ret;

        /*
         * Check if we need to move delayed/dormant tasks from cmds on the
         * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
         * Attribute.
         */
        if (cmd->se_dev->dev_task_attr_type == SAM_TASK_ATTR_EMULATED)
                transport_complete_task_attr(cmd);
        /*
         * Check to schedule QUEUE_FULL work, or execute an existing
         * cmd->transport_qf_callback()
         */
        if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
                schedule_work(&cmd->se_dev->qf_work_queue);

        /*
         * Check if we need to retrieve a sense buffer from
         * the struct se_cmd in question.
         */
        if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
                if (transport_get_sense_data(cmd) < 0)
                        reason = TCM_NON_EXISTENT_LUN;

                /*
                 * Only set when an struct se_task->task_scsi_status returned
                 * a non GOOD status.
                 */
                if (cmd->scsi_status) {
                        ret = transport_send_check_condition_and_sense(
                                        cmd, reason, 1);
                        if (ret == -EAGAIN || ret == -ENOMEM)
                                goto queue_full;

                        transport_lun_remove_cmd(cmd);
                        transport_cmd_check_stop_to_fabric(cmd);
                        return;
                }
        }
        /*
         * Check for a callback, used by amongst other things
         * XDWRITE_READ_10 emulation.
         */
        if (cmd->transport_complete_callback)
                cmd->transport_complete_callback(cmd);

        switch (cmd->data_direction) {
        case DMA_FROM_DEVICE:
                spin_lock(&cmd->se_lun->lun_sep_lock);
                if (cmd->se_lun->lun_sep) {
                        cmd->se_lun->lun_sep->sep_stats.tx_data_octets +=
                                        cmd->data_length;
                }
                spin_unlock(&cmd->se_lun->lun_sep_lock);

                ret = cmd->se_tfo->queue_data_in(cmd);
                if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                break;
        case DMA_TO_DEVICE:
                spin_lock(&cmd->se_lun->lun_sep_lock);
                if (cmd->se_lun->lun_sep) {
                        cmd->se_lun->lun_sep->sep_stats.rx_data_octets +=
                                cmd->data_length;
                }
                spin_unlock(&cmd->se_lun->lun_sep_lock);
                /*
                 * Check if we need to send READ payload for BIDI-COMMAND
                 */
                if (cmd->t_bidi_data_sg) {
                        spin_lock(&cmd->se_lun->lun_sep_lock);
                        if (cmd->se_lun->lun_sep) {
                                cmd->se_lun->lun_sep->sep_stats.tx_data_octets +=
                                        cmd->data_length;
                        }
                        spin_unlock(&cmd->se_lun->lun_sep_lock);
                        ret = cmd->se_tfo->queue_data_in(cmd);
                        if (ret == -EAGAIN || ret == -ENOMEM)
                                goto queue_full;
                        break;
                }
                /* Fall through for DMA_TO_DEVICE */
        case DMA_NONE:
                ret = cmd->se_tfo->queue_status(cmd);
                if (ret == -EAGAIN || ret == -ENOMEM)
                        goto queue_full;
                break;
        default:
                break;
        }

        transport_lun_remove_cmd(cmd);
        transport_cmd_check_stop_to_fabric(cmd);
        return;

queue_full:
        pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
                " data_direction: %d\n", cmd, cmd->data_direction);
        cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
        transport_handle_queue_full(cmd, cmd->se_dev);
}

static void transport_free_dev_tasks(struct se_cmd *cmd)
{
        struct se_task *task, *task_tmp;
        unsigned long flags;
        LIST_HEAD(dispose_list);

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        list_for_each_entry_safe(task, task_tmp,
                                &cmd->t_task_list, t_list) {
                if (!(task->task_flags & TF_ACTIVE))
                        list_move_tail(&task->t_list, &dispose_list);
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        while (!list_empty(&dispose_list)) {
                task = list_first_entry(&dispose_list, struct se_task, t_list);

                if (task->task_sg != cmd->t_data_sg &&
                    task->task_sg != cmd->t_bidi_data_sg)
                        kfree(task->task_sg);

                list_del(&task->t_list);

                cmd->se_dev->transport->free_task(task);
        }
}

static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
{
        struct scatterlist *sg;
        int count;

        for_each_sg(sgl, sg, nents, count)
                __free_page(sg_page(sg));

        kfree(sgl);
}

static inline void transport_free_pages(struct se_cmd *cmd)
{
        if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)
                return;

        transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
        cmd->t_data_sg = NULL;
        cmd->t_data_nents = 0;

        transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
        cmd->t_bidi_data_sg = NULL;
        cmd->t_bidi_data_nents = 0;
}

/**
 * transport_release_cmd - free a command
 * @cmd:       command to free
 *
 * This routine unconditionally frees a command, and reference counting
 * or list removal must be done in the caller.
 */
static void transport_release_cmd(struct se_cmd *cmd)
{
        BUG_ON(!cmd->se_tfo);

        if (cmd->se_tmr_req)
                core_tmr_release_req(cmd->se_tmr_req);
        if (cmd->t_task_cdb != cmd->__t_task_cdb)
                kfree(cmd->t_task_cdb);
        /*
         * Check if target_wait_for_sess_cmds() is expecting to
         * release se_cmd directly here..
         */
        if (cmd->check_release != 0 && cmd->se_tfo->check_release_cmd)
                if (cmd->se_tfo->check_release_cmd(cmd) != 0)
                        return;

        cmd->se_tfo->release_cmd(cmd);
}

/**
 * transport_put_cmd - release a reference to a command
 * @cmd:       command to release
 *
 * This routine releases our reference to the command and frees it if possible.
 */
static void transport_put_cmd(struct se_cmd *cmd)
{
        unsigned long flags;
        int free_tasks = 0;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (atomic_read(&cmd->t_fe_count)) {
                if (!atomic_dec_and_test(&cmd->t_fe_count))
                        goto out_busy;
        }

        if (atomic_read(&cmd->t_se_count)) {
                if (!atomic_dec_and_test(&cmd->t_se_count))
                        goto out_busy;
        }

        if (atomic_read(&cmd->transport_dev_active)) {
                atomic_set(&cmd->transport_dev_active, 0);
                transport_all_task_dev_remove_state(cmd);
                free_tasks = 1;
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        if (free_tasks != 0)
                transport_free_dev_tasks(cmd);

        transport_free_pages(cmd);
        transport_release_cmd(cmd);
        return;
out_busy:
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
}

/*
 * transport_generic_map_mem_to_cmd - Use fabric-alloced pages instead of
 * allocating in the core.
 * @cmd:  Associated se_cmd descriptor
 * @mem:  SGL style memory for TCM WRITE / READ
 * @sg_mem_num: Number of SGL elements
 * @mem_bidi_in: SGL style memory for TCM BIDI READ
 * @sg_mem_bidi_num: Number of BIDI READ SGL elements
 *
 * Return: nonzero return cmd was rejected for -ENOMEM or inproper usage
 * of parameters.
 */
int transport_generic_map_mem_to_cmd(
        struct se_cmd *cmd,
        struct scatterlist *sgl,
        u32 sgl_count,
        struct scatterlist *sgl_bidi,
        u32 sgl_bidi_count)
{
        if (!sgl || !sgl_count)
                return 0;

        if ((cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB) ||
            (cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB)) {
                /*
                 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
                 * scatterlists already have been set to follow what the fabric
                 * passes for the original expected data transfer length.
                 */
                if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
                        pr_warn("Rejecting SCSI DATA overflow for fabric using"
                                " SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
                        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
                        return -EINVAL;
                }

                cmd->t_data_sg = sgl;
                cmd->t_data_nents = sgl_count;

                if (sgl_bidi && sgl_bidi_count) {
                        cmd->t_bidi_data_sg = sgl_bidi;
                        cmd->t_bidi_data_nents = sgl_bidi_count;
                }
                cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
        }

        return 0;
}
EXPORT_SYMBOL(transport_generic_map_mem_to_cmd);

void *transport_kmap_first_data_page(struct se_cmd *cmd)
{
        struct scatterlist *sg = cmd->t_data_sg;

        BUG_ON(!sg);
        /*
         * We need to take into account a possible offset here for fabrics like
         * tcm_loop who may be using a contig buffer from the SCSI midlayer for
         * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
         */
        return kmap(sg_page(sg)) + sg->offset;
}
EXPORT_SYMBOL(transport_kmap_first_data_page);

void transport_kunmap_first_data_page(struct se_cmd *cmd)
{
        kunmap(sg_page(cmd->t_data_sg));
}
EXPORT_SYMBOL(transport_kunmap_first_data_page);

static int
transport_generic_get_mem(struct se_cmd *cmd)
{
        u32 length = cmd->data_length;
        unsigned int nents;
        struct page *page;
        int i = 0;

        nents = DIV_ROUND_UP(length, PAGE_SIZE);
        cmd->t_data_sg = kmalloc(sizeof(struct scatterlist) * nents, GFP_KERNEL);
        if (!cmd->t_data_sg)
                return -ENOMEM;

        cmd->t_data_nents = nents;
        sg_init_table(cmd->t_data_sg, nents);

        while (length) {
                u32 page_len = min_t(u32, length, PAGE_SIZE);
                page = alloc_page(GFP_KERNEL | __GFP_ZERO);
                if (!page)
                        goto out;

                sg_set_page(&cmd->t_data_sg[i], page, page_len, 0);
                length -= page_len;
                i++;
        }
        return 0;

out:
        while (i >= 0) {
                __free_page(sg_page(&cmd->t_data_sg[i]));
                i--;
        }
        kfree(cmd->t_data_sg);
        cmd->t_data_sg = NULL;
        return -ENOMEM;
}

/* Reduce sectors if they are too long for the device */
static inline sector_t transport_limit_task_sectors(
        struct se_device *dev,
        unsigned long long lba,
        sector_t sectors)
{
        sectors = min_t(sector_t, sectors, dev->se_sub_dev->se_dev_attrib.max_sectors);

        if (dev->transport->get_device_type(dev) == TYPE_DISK)
                if ((lba + sectors) > transport_dev_end_lba(dev))
                        sectors = ((transport_dev_end_lba(dev) - lba) + 1);

        return sectors;
}


/*
 * This function can be used by HW target mode drivers to create a linked
 * scatterlist from all contiguously allocated struct se_task->task_sg[].
 * This is intended to be called during the completion path by TCM Core
 * when struct target_core_fabric_ops->check_task_sg_chaining is enabled.
 */
void transport_do_task_sg_chain(struct se_cmd *cmd)
{
        struct scatterlist *sg_first = NULL;
        struct scatterlist *sg_prev = NULL;
        int sg_prev_nents = 0;
        struct scatterlist *sg;
        struct se_task *task;
        u32 chained_nents = 0;
        int i;

        BUG_ON(!cmd->se_tfo->task_sg_chaining);

        /*
         * Walk the struct se_task list and setup scatterlist chains
         * for each contiguously allocated struct se_task->task_sg[].
         */
        list_for_each_entry(task, &cmd->t_task_list, t_list) {
                if (!task->task_sg)
                        continue;

                if (!sg_first) {
                        sg_first = task->task_sg;
                        chained_nents = task->task_sg_nents;
                } else {
                        sg_chain(sg_prev, sg_prev_nents, task->task_sg);
                        chained_nents += task->task_sg_nents;
                }
                /*
                 * For the padded tasks, use the extra SGL vector allocated
                 * in transport_allocate_data_tasks() for the sg_prev_nents
                 * offset into sg_chain() above.
                 *
                 * We do not need the padding for the last task (or a single
                 * task), but in that case we will never use the sg_prev_nents
                 * value below which would be incorrect.
                 */
                sg_prev_nents = (task->task_sg_nents + 1);
                sg_prev = task->task_sg;
        }
        /*
         * Setup the starting pointer and total t_tasks_sg_linked_no including
         * padding SGs for linking and to mark the end.
         */
        cmd->t_tasks_sg_chained = sg_first;
        cmd->t_tasks_sg_chained_no = chained_nents;

        pr_debug("Setup cmd: %p cmd->t_tasks_sg_chained: %p and"
                " t_tasks_sg_chained_no: %u\n", cmd, cmd->t_tasks_sg_chained,
                cmd->t_tasks_sg_chained_no);

        for_each_sg(cmd->t_tasks_sg_chained, sg,
                        cmd->t_tasks_sg_chained_no, i) {

                pr_debug("SG[%d]: %p page: %p length: %d offset: %d\n",
                        i, sg, sg_page(sg), sg->length, sg->offset);
                if (sg_is_chain(sg))
                        pr_debug("SG: %p sg_is_chain=1\n", sg);
                if (sg_is_last(sg))
                        pr_debug("SG: %p sg_is_last=1\n", sg);
        }
}
EXPORT_SYMBOL(transport_do_task_sg_chain);

/*
 * Break up cmd into chunks transport can handle
 */
static int
transport_allocate_data_tasks(struct se_cmd *cmd,
        enum dma_data_direction data_direction,
        struct scatterlist *cmd_sg, unsigned int sgl_nents)
{
        struct se_device *dev = cmd->se_dev;
        int task_count, i;
        unsigned long long lba;
        sector_t sectors, dev_max_sectors;
        u32 sector_size;

        if (transport_cmd_get_valid_sectors(cmd) < 0)
                return -EINVAL;

        dev_max_sectors = dev->se_sub_dev->se_dev_attrib.max_sectors;
        sector_size = dev->se_sub_dev->se_dev_attrib.block_size;

        WARN_ON(cmd->data_length % sector_size);

        lba = cmd->t_task_lba;
        sectors = DIV_ROUND_UP(cmd->data_length, sector_size);
        task_count = DIV_ROUND_UP_SECTOR_T(sectors, dev_max_sectors);

        /*
         * If we need just a single task reuse the SG list in the command
         * and avoid a lot of work.
         */
        if (task_count == 1) {
                struct se_task *task;
                unsigned long flags;

                task = transport_generic_get_task(cmd, data_direction);
                if (!task)
                        return -ENOMEM;

                task->task_sg = cmd_sg;
                task->task_sg_nents = sgl_nents;

                task->task_lba = lba;
                task->task_sectors = sectors;
                task->task_size = task->task_sectors * sector_size;

                spin_lock_irqsave(&cmd->t_state_lock, flags);
                list_add_tail(&task->t_list, &cmd->t_task_list);
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);

                return task_count;
        }

        for (i = 0; i < task_count; i++) {
                struct se_task *task;
                unsigned int task_size, task_sg_nents_padded;
                struct scatterlist *sg;
                unsigned long flags;
                int count;

                task = transport_generic_get_task(cmd, data_direction);
                if (!task)
                        return -ENOMEM;

                task->task_lba = lba;
                task->task_sectors = min(sectors, dev_max_sectors);
                task->task_size = task->task_sectors * sector_size;

                /*
                 * This now assumes that passed sg_ents are in PAGE_SIZE chunks
                 * in order to calculate the number per task SGL entries
                 */
                task->task_sg_nents = DIV_ROUND_UP(task->task_size, PAGE_SIZE);
                /*
                 * Check if the fabric module driver is requesting that all
                 * struct se_task->task_sg[] be chained together..  If so,
                 * then allocate an extra padding SG entry for linking and
                 * marking the end of the chained SGL for every task except
                 * the last one for (task_count > 1) operation, or skipping
                 * the extra padding for the (task_count == 1) case.
                 */
                if (cmd->se_tfo->task_sg_chaining && (i < (task_count - 1))) {
                        task_sg_nents_padded = (task->task_sg_nents + 1);
                } else
                        task_sg_nents_padded = task->task_sg_nents;

                task->task_sg = kmalloc(sizeof(struct scatterlist) *
                                        task_sg_nents_padded, GFP_KERNEL);
                if (!task->task_sg) {
                        cmd->se_dev->transport->free_task(task);
                        return -ENOMEM;
                }

                sg_init_table(task->task_sg, task_sg_nents_padded);

                task_size = task->task_size;

                /* Build new sgl, only up to task_size */
                for_each_sg(task->task_sg, sg, task->task_sg_nents, count) {
                        if (cmd_sg->length > task_size)
                                break;

                        *sg = *cmd_sg;
                        task_size -= cmd_sg->length;
                        cmd_sg = sg_next(cmd_sg);
                }

                lba += task->task_sectors;
                sectors -= task->task_sectors;

                spin_lock_irqsave(&cmd->t_state_lock, flags);
                list_add_tail(&task->t_list, &cmd->t_task_list);
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
        }

        return task_count;
}

static int
transport_allocate_control_task(struct se_cmd *cmd)
{
        struct se_task *task;
        unsigned long flags;

        task = transport_generic_get_task(cmd, cmd->data_direction);
        if (!task)
                return -ENOMEM;

        task->task_sg = cmd->t_data_sg;
        task->task_size = cmd->data_length;
        task->task_sg_nents = cmd->t_data_nents;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        list_add_tail(&task->t_list, &cmd->t_task_list);
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        /* Success! Return number of tasks allocated */
        return 1;
}

/*
 * Allocate any required ressources to execute the command, and either place
 * it on the execution queue if possible.  For writes we might not have the
 * payload yet, thus notify the fabric via a call to ->write_pending instead.
 */
int transport_generic_new_cmd(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        int task_cdbs, task_cdbs_bidi = 0;
        int set_counts = 1;
        int ret = 0;

        /*
         * Determine is the TCM fabric module has already allocated physical
         * memory, and is directly calling transport_generic_map_mem_to_cmd()
         * beforehand.
         */
        if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
            cmd->data_length) {
                ret = transport_generic_get_mem(cmd);
                if (ret < 0)
                        goto out_fail;
        }

        /*
         * For BIDI command set up the read tasks first.
         */
        if (cmd->t_bidi_data_sg &&
            dev->transport->transport_type != TRANSPORT_PLUGIN_PHBA_PDEV) {
                BUG_ON(!(cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB));

                task_cdbs_bidi = transport_allocate_data_tasks(cmd,
                                DMA_FROM_DEVICE, cmd->t_bidi_data_sg,
                                cmd->t_bidi_data_nents);
                if (task_cdbs_bidi <= 0)
                        goto out_fail;

                atomic_inc(&cmd->t_fe_count);
                atomic_inc(&cmd->t_se_count);
                set_counts = 0;
        }

        if (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB) {
                task_cdbs = transport_allocate_data_tasks(cmd,
                                        cmd->data_direction, cmd->t_data_sg,
                                        cmd->t_data_nents);
        } else {
                task_cdbs = transport_allocate_control_task(cmd);
        }

        if (task_cdbs < 0)
                goto out_fail;
        else if (!task_cdbs && (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)) {
                cmd->t_state = TRANSPORT_COMPLETE;
                atomic_set(&cmd->t_transport_active, 1);
                INIT_WORK(&cmd->work, target_complete_ok_work);
                queue_work(target_completion_wq, &cmd->work);
                return 0;
        }

        if (set_counts) {
                atomic_inc(&cmd->t_fe_count);
                atomic_inc(&cmd->t_se_count);
        }

        cmd->t_task_list_num = (task_cdbs + task_cdbs_bidi);
        atomic_set(&cmd->t_task_cdbs_left, cmd->t_task_list_num);
        atomic_set(&cmd->t_task_cdbs_ex_left, cmd->t_task_list_num);

        /*
         * For WRITEs, let the fabric know its buffer is ready..
         * This WRITE struct se_cmd (and all of its associated struct se_task's)
         * will be added to the struct se_device execution queue after its WRITE
         * data has arrived. (ie: It gets handled by the transport processing
         * thread a second time)
         */
        if (cmd->data_direction == DMA_TO_DEVICE) {
                transport_add_tasks_to_state_queue(cmd);
                return transport_generic_write_pending(cmd);
        }
        /*
         * Everything else but a WRITE, add the struct se_cmd's struct se_task's
         * to the execution queue.
         */
        transport_execute_tasks(cmd);
        return 0;

out_fail:
        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
        return -EINVAL;
}
EXPORT_SYMBOL(transport_generic_new_cmd);

/*      transport_generic_process_write():
 *
 *
 */
void transport_generic_process_write(struct se_cmd *cmd)
{
        transport_execute_tasks(cmd);
}
EXPORT_SYMBOL(transport_generic_process_write);

static void transport_write_pending_qf(struct se_cmd *cmd)
{
        int ret;

        ret = cmd->se_tfo->write_pending(cmd);
        if (ret == -EAGAIN || ret == -ENOMEM) {
                pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
                         cmd);
                transport_handle_queue_full(cmd, cmd->se_dev);
        }
}

static int transport_generic_write_pending(struct se_cmd *cmd)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        cmd->t_state = TRANSPORT_WRITE_PENDING;
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        /*
         * Clear the se_cmd for WRITE_PENDING status in order to set
         * cmd->t_transport_active=0 so that transport_generic_handle_data
         * can be called from HW target mode interrupt code.  This is safe
         * to be called with transport_off=1 before the cmd->se_tfo->write_pending
         * because the se_cmd->se_lun pointer is not being cleared.
         */
        transport_cmd_check_stop(cmd, 1, 0);

        /*
         * Call the fabric write_pending function here to let the
         * frontend know that WRITE buffers are ready.
         */
        ret = cmd->se_tfo->write_pending(cmd);
        if (ret == -EAGAIN || ret == -ENOMEM)
                goto queue_full;
        else if (ret < 0)
                return ret;

        return 1;

queue_full:
        pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
        cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
        transport_handle_queue_full(cmd, cmd->se_dev);
        return 0;
}

void transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
{
        if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
                if (wait_for_tasks && cmd->se_tmr_req)
                         transport_wait_for_tasks(cmd);

                transport_release_cmd(cmd);
        } else {
                if (wait_for_tasks)
                        transport_wait_for_tasks(cmd);

                core_dec_lacl_count(cmd->se_sess->se_node_acl, cmd);

                if (cmd->se_lun)
                        transport_lun_remove_cmd(cmd);

                transport_free_dev_tasks(cmd);

                transport_put_cmd(cmd);
        }
}
EXPORT_SYMBOL(transport_generic_free_cmd);

/* target_get_sess_cmd - Add command to active ->sess_cmd_list
 * @se_sess:    session to reference
 * @se_cmd:     command descriptor to add
 */
void target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
{
        unsigned long flags;

        spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
        list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
        se_cmd->check_release = 1;
        spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
}
EXPORT_SYMBOL(target_get_sess_cmd);

/* target_put_sess_cmd - Check for active I/O shutdown or list delete
 * @se_sess:    session to reference
 * @se_cmd:     command descriptor to drop
 */
int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
{
        unsigned long flags;

        spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
        if (list_empty(&se_cmd->se_cmd_list)) {
                spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
                WARN_ON(1);
                return 0;
        }

        if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
                spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
                complete(&se_cmd->cmd_wait_comp);
                return 1;
        }
        list_del(&se_cmd->se_cmd_list);
        spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);

        return 0;
}
EXPORT_SYMBOL(target_put_sess_cmd);

/* target_splice_sess_cmd_list - Split active cmds into sess_wait_list
 * @se_sess:    session to split
 */
void target_splice_sess_cmd_list(struct se_session *se_sess)
{
        struct se_cmd *se_cmd;
        unsigned long flags;

        WARN_ON(!list_empty(&se_sess->sess_wait_list));
        INIT_LIST_HEAD(&se_sess->sess_wait_list);

        spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
        se_sess->sess_tearing_down = 1;

        list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);

        list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
                se_cmd->cmd_wait_set = 1;

        spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
}
EXPORT_SYMBOL(target_splice_sess_cmd_list);

/* target_wait_for_sess_cmds - Wait for outstanding descriptors
 * @se_sess:    session to wait for active I/O
 * @wait_for_tasks:     Make extra transport_wait_for_tasks call
 */
void target_wait_for_sess_cmds(
        struct se_session *se_sess,
        int wait_for_tasks)
{
        struct se_cmd *se_cmd, *tmp_cmd;
        bool rc = false;

        list_for_each_entry_safe(se_cmd, tmp_cmd,
                                &se_sess->sess_wait_list, se_cmd_list) {
                list_del(&se_cmd->se_cmd_list);

                pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
                        " %d\n", se_cmd, se_cmd->t_state,
                        se_cmd->se_tfo->get_cmd_state(se_cmd));

                if (wait_for_tasks) {
                        pr_debug("Calling transport_wait_for_tasks se_cmd: %p t_state: %d,"
                                " fabric state: %d\n", se_cmd, se_cmd->t_state,
                                se_cmd->se_tfo->get_cmd_state(se_cmd));

                        rc = transport_wait_for_tasks(se_cmd);

                        pr_debug("After transport_wait_for_tasks se_cmd: %p t_state: %d,"
                                " fabric state: %d\n", se_cmd, se_cmd->t_state,
                                se_cmd->se_tfo->get_cmd_state(se_cmd));
                }

                if (!rc) {
                        wait_for_completion(&se_cmd->cmd_wait_comp);
                        pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
                                " fabric state: %d\n", se_cmd, se_cmd->t_state,
                                se_cmd->se_tfo->get_cmd_state(se_cmd));
                }

                se_cmd->se_tfo->release_cmd(se_cmd);
        }
}
EXPORT_SYMBOL(target_wait_for_sess_cmds);

/*      transport_lun_wait_for_tasks():
 *
 *      Called from ConfigFS context to stop the passed struct se_cmd to allow
 *      an struct se_lun to be successfully shutdown.
 */
static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun)
{
        unsigned long flags;
        int ret;
        /*
         * If the frontend has already requested this struct se_cmd to
         * be stopped, we can safely ignore this struct se_cmd.
         */
        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (atomic_read(&cmd->t_transport_stop)) {
                atomic_set(&cmd->transport_lun_stop, 0);
                pr_debug("ConfigFS ITT[0x%08x] - t_transport_stop =="
                        " TRUE, skipping\n", cmd->se_tfo->get_task_tag(cmd));
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                transport_cmd_check_stop(cmd, 1, 0);
                return -EPERM;
        }
        atomic_set(&cmd->transport_lun_fe_stop, 1);
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        wake_up_interruptible(&cmd->se_dev->dev_queue_obj.thread_wq);

        ret = transport_stop_tasks_for_cmd(cmd);

        pr_debug("ConfigFS: cmd: %p t_tasks: %d stop tasks ret:"
                        " %d\n", cmd, cmd->t_task_list_num, ret);
        if (!ret) {
                pr_debug("ConfigFS: ITT[0x%08x] - stopping cmd....\n",
                                cmd->se_tfo->get_task_tag(cmd));
                wait_for_completion(&cmd->transport_lun_stop_comp);
                pr_debug("ConfigFS: ITT[0x%08x] - stopped cmd....\n",
                                cmd->se_tfo->get_task_tag(cmd));
        }
        transport_remove_cmd_from_queue(cmd);

        return 0;
}

static void __transport_clear_lun_from_sessions(struct se_lun *lun)
{
        struct se_cmd *cmd = NULL;
        unsigned long lun_flags, cmd_flags;
        /*
         * Do exception processing and return CHECK_CONDITION status to the
         * Initiator Port.
         */
        spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
        while (!list_empty(&lun->lun_cmd_list)) {
                cmd = list_first_entry(&lun->lun_cmd_list,
                       struct se_cmd, se_lun_node);
                list_del(&cmd->se_lun_node);

                atomic_set(&cmd->transport_lun_active, 0);
                /*
                 * This will notify iscsi_target_transport.c:
                 * transport_cmd_check_stop() that a LUN shutdown is in
                 * progress for the iscsi_cmd_t.
                 */
                spin_lock(&cmd->t_state_lock);
                pr_debug("SE_LUN[%d] - Setting cmd->transport"
                        "_lun_stop for  ITT: 0x%08x\n",
                        cmd->se_lun->unpacked_lun,
                        cmd->se_tfo->get_task_tag(cmd));
                atomic_set(&cmd->transport_lun_stop, 1);
                spin_unlock(&cmd->t_state_lock);

                spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);

                if (!cmd->se_lun) {
                        pr_err("ITT: 0x%08x, [i,t]_state: %u/%u\n",
                                cmd->se_tfo->get_task_tag(cmd),
                                cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
                        BUG();
                }
                /*
                 * If the Storage engine still owns the iscsi_cmd_t, determine
                 * and/or stop its context.
                 */
                pr_debug("SE_LUN[%d] - ITT: 0x%08x before transport"
                        "_lun_wait_for_tasks()\n", cmd->se_lun->unpacked_lun,
                        cmd->se_tfo->get_task_tag(cmd));

                if (transport_lun_wait_for_tasks(cmd, cmd->se_lun) < 0) {
                        spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
                        continue;
                }

                pr_debug("SE_LUN[%d] - ITT: 0x%08x after transport_lun"
                        "_wait_for_tasks(): SUCCESS\n",
                        cmd->se_lun->unpacked_lun,
                        cmd->se_tfo->get_task_tag(cmd));

                spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
                if (!atomic_read(&cmd->transport_dev_active)) {
                        spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
                        goto check_cond;
                }
                atomic_set(&cmd->transport_dev_active, 0);
                transport_all_task_dev_remove_state(cmd);
                spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);

                transport_free_dev_tasks(cmd);
                /*
                 * The Storage engine stopped this struct se_cmd before it was
                 * send to the fabric frontend for delivery back to the
                 * Initiator Node.  Return this SCSI CDB back with an
                 * CHECK_CONDITION status.
                 */
check_cond:
                transport_send_check_condition_and_sense(cmd,
                                TCM_NON_EXISTENT_LUN, 0);
                /*
                 *  If the fabric frontend is waiting for this iscsi_cmd_t to
                 * be released, notify the waiting thread now that LU has
                 * finished accessing it.
                 */
                spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
                if (atomic_read(&cmd->transport_lun_fe_stop)) {
                        pr_debug("SE_LUN[%d] - Detected FE stop for"
                                " struct se_cmd: %p ITT: 0x%08x\n",
                                lun->unpacked_lun,
                                cmd, cmd->se_tfo->get_task_tag(cmd));

                        spin_unlock_irqrestore(&cmd->t_state_lock,
                                        cmd_flags);
                        transport_cmd_check_stop(cmd, 1, 0);
                        complete(&cmd->transport_lun_fe_stop_comp);
                        spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
                        continue;
                }
                pr_debug("SE_LUN[%d] - ITT: 0x%08x finished processing\n",
                        lun->unpacked_lun, cmd->se_tfo->get_task_tag(cmd));

                spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
                spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
        }
        spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);
}

static int transport_clear_lun_thread(void *p)
{
        struct se_lun *lun = (struct se_lun *)p;

        __transport_clear_lun_from_sessions(lun);
        complete(&lun->lun_shutdown_comp);

        return 0;
}

int transport_clear_lun_from_sessions(struct se_lun *lun)
{
        struct task_struct *kt;

        kt = kthread_run(transport_clear_lun_thread, lun,
                        "tcm_cl_%u", lun->unpacked_lun);
        if (IS_ERR(kt)) {
                pr_err("Unable to start clear_lun thread\n");
                return PTR_ERR(kt);
        }
        wait_for_completion(&lun->lun_shutdown_comp);

        return 0;
}

/**
 * transport_wait_for_tasks - wait for completion to occur
 * @cmd:        command to wait
 *
 * Called from frontend fabric context to wait for storage engine
 * to pause and/or release frontend generated struct se_cmd.
 */
bool transport_wait_for_tasks(struct se_cmd *cmd)
{
        unsigned long flags;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) && !(cmd->se_tmr_req)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return false;
        }
        /*
         * Only perform a possible wait_for_tasks if SCF_SUPPORTED_SAM_OPCODE
         * has been set in transport_set_supported_SAM_opcode().
         */
        if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) && !cmd->se_tmr_req) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return false;
        }
        /*
         * If we are already stopped due to an external event (ie: LUN shutdown)
         * sleep until the connection can have the passed struct se_cmd back.
         * The cmd->transport_lun_stopped_sem will be upped by
         * transport_clear_lun_from_sessions() once the ConfigFS context caller
         * has completed its operation on the struct se_cmd.
         */
        if (atomic_read(&cmd->transport_lun_stop)) {

                pr_debug("wait_for_tasks: Stopping"
                        " wait_for_completion(&cmd->t_tasktransport_lun_fe"
                        "_stop_comp); for ITT: 0x%08x\n",
                        cmd->se_tfo->get_task_tag(cmd));
                /*
                 * There is a special case for WRITES where a FE exception +
                 * LUN shutdown means ConfigFS context is still sleeping on
                 * transport_lun_stop_comp in transport_lun_wait_for_tasks().
                 * We go ahead and up transport_lun_stop_comp just to be sure
                 * here.
                 */
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                complete(&cmd->transport_lun_stop_comp);
                wait_for_completion(&cmd->transport_lun_fe_stop_comp);
                spin_lock_irqsave(&cmd->t_state_lock, flags);

                transport_all_task_dev_remove_state(cmd);
                /*
                 * At this point, the frontend who was the originator of this
                 * struct se_cmd, now owns the structure and can be released through
                 * normal means below.
                 */
                pr_debug("wait_for_tasks: Stopped"
                        " wait_for_completion(&cmd->t_tasktransport_lun_fe_"
                        "stop_comp); for ITT: 0x%08x\n",
                        cmd->se_tfo->get_task_tag(cmd));

                atomic_set(&cmd->transport_lun_stop, 0);
        }
        if (!atomic_read(&cmd->t_transport_active) ||
             atomic_read(&cmd->t_transport_aborted)) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return false;
        }

        atomic_set(&cmd->t_transport_stop, 1);

        pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08x"
                " i_state: %d, t_state: %d, t_transport_stop = TRUE\n",
                cmd, cmd->se_tfo->get_task_tag(cmd),
                cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);

        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        wake_up_interruptible(&cmd->se_dev->dev_queue_obj.thread_wq);

        wait_for_completion(&cmd->t_transport_stop_comp);

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        atomic_set(&cmd->t_transport_active, 0);
        atomic_set(&cmd->t_transport_stop, 0);

        pr_debug("wait_for_tasks: Stopped wait_for_compltion("
                "&cmd->t_transport_stop_comp) for ITT: 0x%08x\n",
                cmd->se_tfo->get_task_tag(cmd));

        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        return true;
}
EXPORT_SYMBOL(transport_wait_for_tasks);

static int transport_get_sense_codes(
        struct se_cmd *cmd,
        u8 *asc,
        u8 *ascq)
{
        *asc = cmd->scsi_asc;
        *ascq = cmd->scsi_ascq;

        return 0;
}

static int transport_set_sense_codes(
        struct se_cmd *cmd,
        u8 asc,
        u8 ascq)
{
        cmd->scsi_asc = asc;
        cmd->scsi_ascq = ascq;

        return 0;
}

int transport_send_check_condition_and_sense(
        struct se_cmd *cmd,
        u8 reason,
        int from_transport)
{
        unsigned char *buffer = cmd->sense_buffer;
        unsigned long flags;
        int offset;
        u8 asc = 0, ascq = 0;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return 0;
        }
        cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        if (!reason && from_transport)
                goto after_reason;

        if (!from_transport)
                cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
        /*
         * Data Segment and SenseLength of the fabric response PDU.
         *
         * TRANSPORT_SENSE_BUFFER is now set to SCSI_SENSE_BUFFERSIZE
         * from include/scsi/scsi_cmnd.h
         */
        offset = cmd->se_tfo->set_fabric_sense_len(cmd,
                                TRANSPORT_SENSE_BUFFER);
        /*
         * Actual SENSE DATA, see SPC-3 7.23.2  SPC_SENSE_KEY_OFFSET uses
         * SENSE KEY values from include/scsi/scsi.h
         */
        switch (reason) {
        case TCM_NON_EXISTENT_LUN:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ILLEGAL REQUEST */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
                /* LOGICAL UNIT NOT SUPPORTED */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x25;
                break;
        case TCM_UNSUPPORTED_SCSI_OPCODE:
        case TCM_SECTOR_COUNT_TOO_MANY:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ILLEGAL REQUEST */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
                /* INVALID COMMAND OPERATION CODE */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x20;
                break;
        case TCM_UNKNOWN_MODE_PAGE:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ILLEGAL REQUEST */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
                /* INVALID FIELD IN CDB */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x24;
                break;
        case TCM_CHECK_CONDITION_ABORT_CMD:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* BUS DEVICE RESET FUNCTION OCCURRED */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x29;
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = 0x03;
                break;
        case TCM_INCORRECT_AMOUNT_OF_DATA:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* WRITE ERROR */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x0c;
                /* NOT ENOUGH UNSOLICITED DATA */
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = 0x0d;
                break;
        case TCM_INVALID_CDB_FIELD:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* INVALID FIELD IN CDB */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x24;
                break;
        case TCM_INVALID_PARAMETER_LIST:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* INVALID FIELD IN PARAMETER LIST */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x26;
                break;
        case TCM_UNEXPECTED_UNSOLICITED_DATA:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* WRITE ERROR */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x0c;
                /* UNEXPECTED_UNSOLICITED_DATA */
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = 0x0c;
                break;
        case TCM_SERVICE_CRC_ERROR:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* PROTOCOL SERVICE CRC ERROR */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x47;
                /* N/A */
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = 0x05;
                break;
        case TCM_SNACK_REJECTED:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ABORTED COMMAND */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
                /* READ ERROR */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x11;
                /* FAILED RETRANSMISSION REQUEST */
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = 0x13;
                break;
        case TCM_WRITE_PROTECTED:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* DATA PROTECT */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = DATA_PROTECT;
                /* WRITE PROTECTED */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x27;
                break;
        case TCM_CHECK_CONDITION_UNIT_ATTENTION:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* UNIT ATTENTION */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = UNIT_ATTENTION;
                core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
                buffer[offset+SPC_ASC_KEY_OFFSET] = asc;
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = ascq;
                break;
        case TCM_CHECK_CONDITION_NOT_READY:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* Not Ready */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = NOT_READY;
                transport_get_sense_codes(cmd, &asc, &ascq);
                buffer[offset+SPC_ASC_KEY_OFFSET] = asc;
                buffer[offset+SPC_ASCQ_KEY_OFFSET] = ascq;
                break;
        case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
        default:
                /* CURRENT ERROR */
                buffer[offset] = 0x70;
                /* ILLEGAL REQUEST */
                buffer[offset+SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
                /* LOGICAL UNIT COMMUNICATION FAILURE */
                buffer[offset+SPC_ASC_KEY_OFFSET] = 0x80;
                break;
        }
        /*
         * This code uses linux/include/scsi/scsi.h SAM status codes!
         */
        cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
        /*
         * Automatically padded, this value is encoded in the fabric's
         * data_length response PDU containing the SCSI defined sense data.
         */
        cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER + offset;

after_reason:
        return cmd->se_tfo->queue_status(cmd);
}
EXPORT_SYMBOL(transport_send_check_condition_and_sense);

int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
{
        int ret = 0;

        if (atomic_read(&cmd->t_transport_aborted) != 0) {
                if (!send_status ||
                     (cmd->se_cmd_flags & SCF_SENT_DELAYED_TAS))
                        return 1;
#if 0
                pr_debug("Sending delayed SAM_STAT_TASK_ABORTED"
                        " status for CDB: 0x%02x ITT: 0x%08x\n",
                        cmd->t_task_cdb[0],
                        cmd->se_tfo->get_task_tag(cmd));
#endif
                cmd->se_cmd_flags |= SCF_SENT_DELAYED_TAS;
                cmd->se_tfo->queue_status(cmd);
                ret = 1;
        }
        return ret;
}
EXPORT_SYMBOL(transport_check_aborted_status);

void transport_send_task_abort(struct se_cmd *cmd)
{
        unsigned long flags;

        spin_lock_irqsave(&cmd->t_state_lock, flags);
        if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
                return;
        }
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);

        /*
         * If there are still expected incoming fabric WRITEs, we wait
         * until until they have completed before sending a TASK_ABORTED
         * response.  This response with TASK_ABORTED status will be
         * queued back to fabric module by transport_check_aborted_status().
         */
        if (cmd->data_direction == DMA_TO_DEVICE) {
                if (cmd->se_tfo->write_pending_status(cmd) != 0) {
                        atomic_inc(&cmd->t_transport_aborted);
                        smp_mb__after_atomic_inc();
                }
        }
        cmd->scsi_status = SAM_STAT_TASK_ABORTED;
#if 0
        pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x,"
                " ITT: 0x%08x\n", cmd->t_task_cdb[0],
                cmd->se_tfo->get_task_tag(cmd));
#endif
        cmd->se_tfo->queue_status(cmd);
}

static int transport_generic_do_tmr(struct se_cmd *cmd)
{
        struct se_device *dev = cmd->se_dev;
        struct se_tmr_req *tmr = cmd->se_tmr_req;
        int ret;

        switch (tmr->function) {
        case TMR_ABORT_TASK:
                tmr->response = TMR_FUNCTION_REJECTED;
                break;
        case TMR_ABORT_TASK_SET:
        case TMR_CLEAR_ACA:
        case TMR_CLEAR_TASK_SET:
                tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
                break;
        case TMR_LUN_RESET:
                ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
                tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
                                         TMR_FUNCTION_REJECTED;
                break;
        case TMR_TARGET_WARM_RESET:
                tmr->response = TMR_FUNCTION_REJECTED;
                break;
        case TMR_TARGET_COLD_RESET:
                tmr->response = TMR_FUNCTION_REJECTED;
                break;
        default:
                pr_err("Uknown TMR function: 0x%02x.\n",
                                tmr->function);
                tmr->response = TMR_FUNCTION_REJECTED;
                break;
        }

        cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
        cmd->se_tfo->queue_tm_rsp(cmd);

        transport_cmd_check_stop_to_fabric(cmd);
        return 0;
}

/*      transport_processing_thread():
 *
 *
 */
static int transport_processing_thread(void *param)
{
        int ret;
        struct se_cmd *cmd;
        struct se_device *dev = (struct se_device *) param;

        while (!kthread_should_stop()) {
                ret = wait_event_interruptible(dev->dev_queue_obj.thread_wq,
                                atomic_read(&dev->dev_queue_obj.queue_cnt) ||
                                kthread_should_stop());
                if (ret < 0)
                        goto out;

get_cmd:
                __transport_execute_tasks(dev);

                cmd = transport_get_cmd_from_queue(&dev->dev_queue_obj);
                if (!cmd)
                        continue;

                switch (cmd->t_state) {
                case TRANSPORT_NEW_CMD:
                        BUG();
                        break;
                case TRANSPORT_NEW_CMD_MAP:
                        if (!cmd->se_tfo->new_cmd_map) {
                                pr_err("cmd->se_tfo->new_cmd_map is"
                                        " NULL for TRANSPORT_NEW_CMD_MAP\n");
                                BUG();
                        }
                        ret = cmd->se_tfo->new_cmd_map(cmd);
                        if (ret < 0) {
                                transport_generic_request_failure(cmd);
                                break;
                        }
                        ret = transport_generic_new_cmd(cmd);
                        if (ret < 0) {
                                transport_generic_request_failure(cmd);
                                break;
                        }
                        break;
                case TRANSPORT_PROCESS_WRITE:
                        transport_generic_process_write(cmd);
                        break;
                case TRANSPORT_PROCESS_TMR:
                        transport_generic_do_tmr(cmd);
                        break;
                case TRANSPORT_COMPLETE_QF_WP:
                        transport_write_pending_qf(cmd);
                        break;
                case TRANSPORT_COMPLETE_QF_OK:
                        transport_complete_qf(cmd);
                        break;
                default:
                        pr_err("Unknown t_state: %d  for ITT: 0x%08x "
                                "i_state: %d on SE LUN: %u\n",
                                cmd->t_state,
                                cmd->se_tfo->get_task_tag(cmd),
                                cmd->se_tfo->get_cmd_state(cmd),
                                cmd->se_lun->unpacked_lun);
                        BUG();
                }

                goto get_cmd;
        }

out:
        WARN_ON(!list_empty(&dev->state_task_list));
        WARN_ON(!list_empty(&dev->dev_queue_obj.qobj_list));
        dev->process_thread = NULL;
        return 0;
}