target_core_alua.c

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/*******************************************************************************
 * Filename:  target_core_alua.c
 *
 * This file contains SPC-3 compliant asymmetric logical unit assigntment (ALUA)
 *
 * Copyright (c) 2009-2010 Rising Tide Systems
 * Copyright (c) 2009-2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/configfs.h>
#include <linux/export.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <asm/unaligned.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_ua.h"

static int core_alua_check_transition(int state, int *primary);
static int core_alua_set_tg_pt_secondary_state(
        struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
        struct se_port *port, int explict, int offline);

static u16 alua_lu_gps_counter;
static u32 alua_lu_gps_count;

static DEFINE_SPINLOCK(lu_gps_lock);
static LIST_HEAD(lu_gps_list);

struct t10_alua_lu_gp *default_lu_gp;

/*
 * REPORT_TARGET_PORT_GROUPS
 *
 * See spc4r17 section 6.27
 */
int target_emulate_report_target_port_groups(struct se_cmd *cmd)
{
    struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
    struct se_port *port;
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
    unsigned char *buf;
    u32 rd_len = 0, off;
    int ext_hdr = (cmd->t_task_cdb[1] & 0x20);
    /*
     * Skip over RESERVED area to first Target port group descriptor
     * depending on the PARAMETER DATA FORMAT type..
     */
    if (ext_hdr != 0)
        off = 8;
    else
        off = 4;

    if (cmd->data_length < off) {
        pr_warn("REPORT TARGET PORT GROUPS allocation length %u too"
            " small for %s header\n", cmd->data_length,
            (ext_hdr) ? "extended" : "normal");
        cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
        return -EINVAL;
    }
    buf = transport_kmap_data_sg(cmd);

    spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
    list_for_each_entry(tg_pt_gp, &su_dev->t10_alua.tg_pt_gps_list,
            tg_pt_gp_list) {
        /*
         * Check if the Target port group and Target port descriptor list
         * based on tg_pt_gp_members count will fit into the response payload.
         * Otherwise, bump rd_len to let the initiator know we have exceeded
         * the allocation length and the response is truncated.
         */
        if ((off + 8 + (tg_pt_gp->tg_pt_gp_members * 4)) >
             cmd->data_length) {
            rd_len += 8 + (tg_pt_gp->tg_pt_gp_members * 4);
            continue;
        }
        /*
         * PREF: Preferred target port bit, determine if this
         * bit should be set for port group.
         */
        if (tg_pt_gp->tg_pt_gp_pref)
            buf[off] = 0x80;
        /*
         * Set the ASYMMETRIC ACCESS State
         */
        buf[off++] |= (atomic_read(
            &tg_pt_gp->tg_pt_gp_alua_access_state) & 0xff);
        /*
         * Set supported ASYMMETRIC ACCESS State bits
         */
        buf[off] = 0x80; /* T_SUP */
        buf[off] |= 0x40; /* O_SUP */
        buf[off] |= 0x8; /* U_SUP */
        buf[off] |= 0x4; /* S_SUP */
        buf[off] |= 0x2; /* AN_SUP */
        buf[off++] |= 0x1; /* AO_SUP */
        /*
         * TARGET PORT GROUP
         */
        buf[off++] = ((tg_pt_gp->tg_pt_gp_id >> 8) & 0xff);
        buf[off++] = (tg_pt_gp->tg_pt_gp_id & 0xff);

        off++; /* Skip over Reserved */
        /*
         * STATUS CODE
         */
        buf[off++] = (tg_pt_gp->tg_pt_gp_alua_access_status & 0xff);
        /*
         * Vendor Specific field
         */
        buf[off++] = 0x00;
        /*
         * TARGET PORT COUNT
         */
        buf[off++] = (tg_pt_gp->tg_pt_gp_members & 0xff);
        rd_len += 8;

        spin_lock(&tg_pt_gp->tg_pt_gp_lock);
        list_for_each_entry(tg_pt_gp_mem, &tg_pt_gp->tg_pt_gp_mem_list,
                tg_pt_gp_mem_list) {
            port = tg_pt_gp_mem->tg_pt;
            /*
             * Start Target Port descriptor format
             *
             * See spc4r17 section 6.2.7 Table 247
             */
            off += 2; /* Skip over Obsolete */
            /*
             * Set RELATIVE TARGET PORT IDENTIFIER
             */
            buf[off++] = ((port->sep_rtpi >> 8) & 0xff);
            buf[off++] = (port->sep_rtpi & 0xff);
            rd_len += 4;
        }
        spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
    }
    spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
    /*
     * Set the RETURN DATA LENGTH set in the header of the DataIN Payload
     */
    put_unaligned_be32(rd_len, &buf[0]);

    /*
     * Fill in the Extended header parameter data format if requested
     */
    if (ext_hdr != 0) {
        buf[4] = 0x10;
        /*
         * Set the implict transition time (in seconds) for the application
         * client to use as a base for it's transition timeout value.
         *
         * Use the current tg_pt_gp_mem -> tg_pt_gp membership from the LUN
         * this CDB was received upon to determine this value individually
         * for ALUA target port group.
         */
        port = cmd->se_lun->lun_sep;
        tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
        if (tg_pt_gp_mem) {
            spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
            tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
            if (tg_pt_gp)
                buf[5] = tg_pt_gp->tg_pt_gp_implict_trans_secs;
            spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
        }
    }
    transport_kunmap_data_sg(cmd);

    target_complete_cmd(cmd, GOOD);
    return 0;
}

/*
 * SET_TARGET_PORT_GROUPS for explict ALUA operation.
 *
 * See spc4r17 section 6.35
 */
int target_emulate_set_target_port_groups(struct se_cmd *cmd)
{
    struct se_device *dev = cmd->se_dev;
    struct se_subsystem_dev *su_dev = dev->se_sub_dev;
    struct se_port *port, *l_port = cmd->se_lun->lun_sep;
    struct se_node_acl *nacl = cmd->se_sess->se_node_acl;
    struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *l_tg_pt_gp;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem, *l_tg_pt_gp_mem;
    unsigned char *buf;
    unsigned char *ptr;
    u32 len = 4; /* Skip over RESERVED area in header */
    int alua_access_state, primary = 0, rc;
    u16 tg_pt_id, rtpi;

    if (!l_port) {
        cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
        return -EINVAL;
    }
    if (cmd->data_length < 4) {
        pr_warn("SET TARGET PORT GROUPS parameter list length %u too"
            " small\n", cmd->data_length);
        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
        return -EINVAL;
    }

    buf = transport_kmap_data_sg(cmd);

    /*
     * Determine if explict ALUA via SET_TARGET_PORT_GROUPS is allowed
     * for the local tg_pt_gp.
     */
    l_tg_pt_gp_mem = l_port->sep_alua_tg_pt_gp_mem;
    if (!l_tg_pt_gp_mem) {
        pr_err("Unable to access l_port->sep_alua_tg_pt_gp_mem\n");
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        rc = -EINVAL;
        goto out;
    }
    spin_lock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
    l_tg_pt_gp = l_tg_pt_gp_mem->tg_pt_gp;
    if (!l_tg_pt_gp) {
        spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
        pr_err("Unable to access *l_tg_pt_gp_mem->tg_pt_gp\n");
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        rc = -EINVAL;
        goto out;
    }
    rc = (l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA);
    spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);

    if (!rc) {
        pr_debug("Unable to process SET_TARGET_PORT_GROUPS"
                " while TPGS_EXPLICT_ALUA is disabled\n");
        cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
        rc = -EINVAL;
        goto out;
    }

    ptr = &buf[4]; /* Skip over RESERVED area in header */

    while (len < cmd->data_length) {
        alua_access_state = (ptr[0] & 0x0f);
        /*
         * Check the received ALUA access state, and determine if
         * the state is a primary or secondary target port asymmetric
         * access state.
         */
        rc = core_alua_check_transition(alua_access_state, &primary);
        if (rc != 0) {
            /*
             * If the SET TARGET PORT GROUPS attempts to establish
             * an invalid combination of target port asymmetric
             * access states or attempts to establish an
             * unsupported target port asymmetric access state,
             * then the command shall be terminated with CHECK
             * CONDITION status, with the sense key set to ILLEGAL
             * REQUEST, and the additional sense code set to INVALID
             * FIELD IN PARAMETER LIST.
             */
            cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
            rc = -EINVAL;
            goto out;
        }
        rc = -1;
        /*
         * If the ASYMMETRIC ACCESS STATE field (see table 267)
         * specifies a primary target port asymmetric access state,
         * then the TARGET PORT GROUP OR TARGET PORT field specifies
         * a primary target port group for which the primary target
         * port asymmetric access state shall be changed. If the
         * ASYMMETRIC ACCESS STATE field specifies a secondary target
         * port asymmetric access state, then the TARGET PORT GROUP OR
         * TARGET PORT field specifies the relative target port
         * identifier (see 3.1.120) of the target port for which the
         * secondary target port asymmetric access state shall be
         * changed.
         */
        if (primary) {
            tg_pt_id = get_unaligned_be16(ptr + 2);
            /*
             * Locate the matching target port group ID from
             * the global tg_pt_gp list
             */
            spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
            list_for_each_entry(tg_pt_gp,
                    &su_dev->t10_alua.tg_pt_gps_list,
                    tg_pt_gp_list) {
                if (!tg_pt_gp->tg_pt_gp_valid_id)
                    continue;

                if (tg_pt_id != tg_pt_gp->tg_pt_gp_id)
                    continue;

                atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
                smp_mb__after_atomic_inc();
                spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);

                rc = core_alua_do_port_transition(tg_pt_gp,
                        dev, l_port, nacl,
                        alua_access_state, 1);

                spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
                atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
                smp_mb__after_atomic_dec();
                break;
            }
            spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
            /*
             * If not matching target port group ID can be located
             * throw an exception with ASCQ: INVALID_PARAMETER_LIST
             */
            if (rc != 0) {
                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                rc = -EINVAL;
                goto out;
            }
        } else {
            /*
             * Extact the RELATIVE TARGET PORT IDENTIFIER to identify
             * the Target Port in question for the the incoming
             * SET_TARGET_PORT_GROUPS op.
             */
            rtpi = get_unaligned_be16(ptr + 2);
            /*
             * Locate the matching relative target port identifier
             * for the struct se_device storage object.
             */
            spin_lock(&dev->se_port_lock);
            list_for_each_entry(port, &dev->dev_sep_list,
                            sep_list) {
                if (port->sep_rtpi != rtpi)
                    continue;

                tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
                spin_unlock(&dev->se_port_lock);

                rc = core_alua_set_tg_pt_secondary_state(
                        tg_pt_gp_mem, port, 1, 1);

                spin_lock(&dev->se_port_lock);
                break;
            }
            spin_unlock(&dev->se_port_lock);
            /*
             * If not matching relative target port identifier can
             * be located, throw an exception with ASCQ:
             * INVALID_PARAMETER_LIST
             */
            if (rc != 0) {
                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                rc = -EINVAL;
                goto out;
            }
        }

        ptr += 4;
        len += 4;
    }

out:
    transport_kunmap_data_sg(cmd);
    if (!rc)
        target_complete_cmd(cmd, GOOD);
    return rc;
}

static inline int core_alua_state_nonoptimized(
    struct se_cmd *cmd,
    unsigned char *cdb,
    int nonop_delay_msecs,
    u8 *alua_ascq)
{
    /*
     * Set SCF_ALUA_NON_OPTIMIZED here, this value will be checked
     * later to determine if processing of this cmd needs to be
     * temporarily delayed for the Active/NonOptimized primary access state.
     */
    cmd->se_cmd_flags |= SCF_ALUA_NON_OPTIMIZED;
    cmd->alua_nonop_delay = nonop_delay_msecs;
    return 0;
}

static inline int core_alua_state_standby(
    struct se_cmd *cmd,
    unsigned char *cdb,
    u8 *alua_ascq)
{
    /*
     * Allowed CDBs for ALUA_ACCESS_STATE_STANDBY as defined by
     * spc4r17 section 5.9.2.4.4
     */
    switch (cdb[0]) {
    case INQUIRY:
    case LOG_SELECT:
    case LOG_SENSE:
    case MODE_SELECT:
    case MODE_SENSE:
    case REPORT_LUNS:
    case RECEIVE_DIAGNOSTIC:
    case SEND_DIAGNOSTIC:
    case MAINTENANCE_IN:
        switch (cdb[1] & 0x1f) {
        case MI_REPORT_TARGET_PGS:
            return 0;
        default:
            *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
            return 1;
        }
    case MAINTENANCE_OUT:
        switch (cdb[1]) {
        case MO_SET_TARGET_PGS:
            return 0;
        default:
            *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
            return 1;
        }
    case REQUEST_SENSE:
    case PERSISTENT_RESERVE_IN:
    case PERSISTENT_RESERVE_OUT:
    case READ_BUFFER:
    case WRITE_BUFFER:
        return 0;
    default:
        *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
        return 1;
    }

    return 0;
}

static inline int core_alua_state_unavailable(
    struct se_cmd *cmd,
    unsigned char *cdb,
    u8 *alua_ascq)
{
    /*
     * Allowed CDBs for ALUA_ACCESS_STATE_UNAVAILABLE as defined by
     * spc4r17 section 5.9.2.4.5
     */
    switch (cdb[0]) {
    case INQUIRY:
    case REPORT_LUNS:
    case MAINTENANCE_IN:
        switch (cdb[1] & 0x1f) {
        case MI_REPORT_TARGET_PGS:
            return 0;
        default:
            *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
            return 1;
        }
    case MAINTENANCE_OUT:
        switch (cdb[1]) {
        case MO_SET_TARGET_PGS:
            return 0;
        default:
            *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
            return 1;
        }
    case REQUEST_SENSE:
    case READ_BUFFER:
    case WRITE_BUFFER:
        return 0;
    default:
        *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
        return 1;
    }

    return 0;
}

static inline int core_alua_state_transition(
    struct se_cmd *cmd,
    unsigned char *cdb,
    u8 *alua_ascq)
{
    /*
     * Allowed CDBs for ALUA_ACCESS_STATE_TRANSITIO as defined by
     * spc4r17 section 5.9.2.5
     */
    switch (cdb[0]) {
    case INQUIRY:
    case REPORT_LUNS:
    case MAINTENANCE_IN:
        switch (cdb[1] & 0x1f) {
        case MI_REPORT_TARGET_PGS:
            return 0;
        default:
            *alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
            return 1;
        }
    case REQUEST_SENSE:
    case READ_BUFFER:
    case WRITE_BUFFER:
        return 0;
    default:
        *alua_ascq = ASCQ_04H_ALUA_STATE_TRANSITION;
        return 1;
    }

    return 0;
}

/*
 * Used for alua_type SPC_ALUA_PASSTHROUGH and SPC2_ALUA_DISABLED
 * in transport_cmd_sequencer().  This function is assigned to
 * struct t10_alua *->state_check() in core_setup_alua()
 */
static int core_alua_state_check_nop(
    struct se_cmd *cmd,
    unsigned char *cdb,
    u8 *alua_ascq)
{
    return 0;
}

/*
 * Used for alua_type SPC3_ALUA_EMULATED in transport_cmd_sequencer().
 * This function is assigned to struct t10_alua *->state_check() in
 * core_setup_alua()
 *
 * Also, this function can return three different return codes to
 * signal transport_generic_cmd_sequencer()
 *
 * return 1: Is used to signal LUN not accecsable, and check condition/not ready
 * return 0: Used to signal success
 * reutrn -1: Used to signal failure, and invalid cdb field
 */
static int core_alua_state_check(
    struct se_cmd *cmd,
    unsigned char *cdb,
    u8 *alua_ascq)
{
    struct se_lun *lun = cmd->se_lun;
    struct se_port *port = lun->lun_sep;
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
    int out_alua_state, nonop_delay_msecs;

    if (!port)
        return 0;
    /*
     * First, check for a struct se_port specific secondary ALUA target port
     * access state: OFFLINE
     */
    if (atomic_read(&port->sep_tg_pt_secondary_offline)) {
        *alua_ascq = ASCQ_04H_ALUA_OFFLINE;
        pr_debug("ALUA: Got secondary offline status for local"
                " target port\n");
        *alua_ascq = ASCQ_04H_ALUA_OFFLINE;
        return 1;
    }
     /*
     * Second, obtain the struct t10_alua_tg_pt_gp_member pointer to the
     * ALUA target port group, to obtain current ALUA access state.
     * Otherwise look for the underlying struct se_device association with
     * a ALUA logical unit group.
     */
    tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
    spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
    out_alua_state = atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
    nonop_delay_msecs = tg_pt_gp->tg_pt_gp_nonop_delay_msecs;
    spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    /*
     * Process ALUA_ACCESS_STATE_ACTIVE_OPTMIZED in a separate conditional
     * statement so the compiler knows explicitly to check this case first.
     * For the Optimized ALUA access state case, we want to process the
     * incoming fabric cmd ASAP..
     */
    if (out_alua_state == ALUA_ACCESS_STATE_ACTIVE_OPTMIZED)
        return 0;

    switch (out_alua_state) {
    case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
        return core_alua_state_nonoptimized(cmd, cdb,
                    nonop_delay_msecs, alua_ascq);
    case ALUA_ACCESS_STATE_STANDBY:
        return core_alua_state_standby(cmd, cdb, alua_ascq);
    case ALUA_ACCESS_STATE_UNAVAILABLE:
        return core_alua_state_unavailable(cmd, cdb, alua_ascq);
    case ALUA_ACCESS_STATE_TRANSITION:
        return core_alua_state_transition(cmd, cdb, alua_ascq);
    /*
     * OFFLINE is a secondary ALUA target port group access state, that is
     * handled above with struct se_port->sep_tg_pt_secondary_offline=1
     */
    case ALUA_ACCESS_STATE_OFFLINE:
    default:
        pr_err("Unknown ALUA access state: 0x%02x\n",
                out_alua_state);
        return -EINVAL;
    }

    return 0;
}

/*
 * Check implict and explict ALUA state change request.
 */
static int core_alua_check_transition(int state, int *primary)
{
    switch (state) {
    case ALUA_ACCESS_STATE_ACTIVE_OPTMIZED:
    case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
    case ALUA_ACCESS_STATE_STANDBY:
    case ALUA_ACCESS_STATE_UNAVAILABLE:
        /*
         * OPTIMIZED, NON-OPTIMIZED, STANDBY and UNAVAILABLE are
         * defined as primary target port asymmetric access states.
         */
        *primary = 1;
        break;
    case ALUA_ACCESS_STATE_OFFLINE:
        /*
         * OFFLINE state is defined as a secondary target port
         * asymmetric access state.
         */
        *primary = 0;
        break;
    default:
        pr_err("Unknown ALUA access state: 0x%02x\n", state);
        return -EINVAL;
    }

    return 0;
}

static char *core_alua_dump_state(int state)
{
    switch (state) {
    case ALUA_ACCESS_STATE_ACTIVE_OPTMIZED:
        return "Active/Optimized";
    case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
        return "Active/NonOptimized";
    case ALUA_ACCESS_STATE_STANDBY:
        return "Standby";
    case ALUA_ACCESS_STATE_UNAVAILABLE:
        return "Unavailable";
    case ALUA_ACCESS_STATE_OFFLINE:
        return "Offline";
    default:
        return "Unknown";
    }

    return NULL;
}

char *core_alua_dump_status(int status)
{
    switch (status) {
    case ALUA_STATUS_NONE:
        return "None";
    case ALUA_STATUS_ALTERED_BY_EXPLICT_STPG:
        return "Altered by Explict STPG";
    case ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA:
        return "Altered by Implict ALUA";
    default:
        return "Unknown";
    }

    return NULL;
}

/*
 * Used by fabric modules to determine when we need to delay processing
 * for the Active/NonOptimized paths..
 */
int core_alua_check_nonop_delay(
    struct se_cmd *cmd)
{
    if (!(cmd->se_cmd_flags & SCF_ALUA_NON_OPTIMIZED))
        return 0;
    if (in_interrupt())
        return 0;
    /*
     * The ALUA Active/NonOptimized access state delay can be disabled
     * in via configfs with a value of zero
     */
    if (!cmd->alua_nonop_delay)
        return 0;
    /*
     * struct se_cmd->alua_nonop_delay gets set by a target port group
     * defined interval in core_alua_state_nonoptimized()
     */
    msleep_interruptible(cmd->alua_nonop_delay);
    return 0;
}
EXPORT_SYMBOL(core_alua_check_nonop_delay);

/*
 * Called with tg_pt_gp->tg_pt_gp_md_mutex or tg_pt_gp_mem->sep_tg_pt_md_mutex
 *
 */
static int core_alua_write_tpg_metadata(
    const char *path,
    unsigned char *md_buf,
    u32 md_buf_len)
{
    mm_segment_t old_fs;
    struct file *file;
    struct iovec iov[1];
    int flags = O_RDWR | O_CREAT | O_TRUNC, ret;

    memset(iov, 0, sizeof(struct iovec));

    file = filp_open(path, flags, 0600);
    if (IS_ERR(file) || !file || !file->f_dentry) {
        pr_err("filp_open(%s) for ALUA metadata failed\n",
            path);
        return -ENODEV;
    }

    iov[0].iov_base = &md_buf[0];
    iov[0].iov_len = md_buf_len;

    old_fs = get_fs();
    set_fs(get_ds());
    ret = vfs_writev(file, &iov[0], 1, &file->f_pos);
    set_fs(old_fs);

    if (ret < 0) {
        pr_err("Error writing ALUA metadata file: %s\n", path);
        filp_close(file, NULL);
        return -EIO;
    }
    filp_close(file, NULL);

    return 0;
}

/*
 * Called with tg_pt_gp->tg_pt_gp_md_mutex held
 */
static int core_alua_update_tpg_primary_metadata(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    int primary_state,
    unsigned char *md_buf)
{
    struct se_subsystem_dev *su_dev = tg_pt_gp->tg_pt_gp_su_dev;
    struct t10_wwn *wwn = &su_dev->t10_wwn;
    char path[ALUA_METADATA_PATH_LEN];
    int len;

    memset(path, 0, ALUA_METADATA_PATH_LEN);

    len = snprintf(md_buf, tg_pt_gp->tg_pt_gp_md_buf_len,
            "tg_pt_gp_id=%hu\n"
            "alua_access_state=0x%02x\n"
            "alua_access_status=0x%02x\n",
            tg_pt_gp->tg_pt_gp_id, primary_state,
            tg_pt_gp->tg_pt_gp_alua_access_status);

    snprintf(path, ALUA_METADATA_PATH_LEN,
        "/var/target/alua/tpgs_%s/%s", &wwn->unit_serial[0],
        config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item));

    return core_alua_write_tpg_metadata(path, md_buf, len);
}

static int core_alua_do_transition_tg_pt(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    struct se_port *l_port,
    struct se_node_acl *nacl,
    unsigned char *md_buf,
    int new_state,
    int explict)
{
    struct se_dev_entry *se_deve;
    struct se_lun_acl *lacl;
    struct se_port *port;
    struct t10_alua_tg_pt_gp_member *mem;
    int old_state = 0;
    /*
     * Save the old primary ALUA access state, and set the current state
     * to ALUA_ACCESS_STATE_TRANSITION.
     */
    old_state = atomic_read(&tg_pt_gp->tg_pt_gp_alua_access_state);
    atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
            ALUA_ACCESS_STATE_TRANSITION);
    tg_pt_gp->tg_pt_gp_alua_access_status = (explict) ?
                ALUA_STATUS_ALTERED_BY_EXPLICT_STPG :
                ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA;
    /*
     * Check for the optional ALUA primary state transition delay
     */
    if (tg_pt_gp->tg_pt_gp_trans_delay_msecs != 0)
        msleep_interruptible(tg_pt_gp->tg_pt_gp_trans_delay_msecs);

    spin_lock(&tg_pt_gp->tg_pt_gp_lock);
    list_for_each_entry(mem, &tg_pt_gp->tg_pt_gp_mem_list,
                tg_pt_gp_mem_list) {
        port = mem->tg_pt;
        /*
         * After an implicit target port asymmetric access state
         * change, a device server shall establish a unit attention
         * condition for the initiator port associated with every I_T
         * nexus with the additional sense code set to ASYMMETRIC
         * ACCESS STATE CHAGED.
         *
         * After an explicit target port asymmetric access state
         * change, a device server shall establish a unit attention
         * condition with the additional sense code set to ASYMMETRIC
         * ACCESS STATE CHANGED for the initiator port associated with
         * every I_T nexus other than the I_T nexus on which the SET
         * TARGET PORT GROUPS command
         */
        atomic_inc(&mem->tg_pt_gp_mem_ref_cnt);
        smp_mb__after_atomic_inc();
        spin_unlock(&tg_pt_gp->tg_pt_gp_lock);

        spin_lock_bh(&port->sep_alua_lock);
        list_for_each_entry(se_deve, &port->sep_alua_list,
                    alua_port_list) {
            lacl = se_deve->se_lun_acl;
            /*
             * se_deve->se_lun_acl pointer may be NULL for a
             * entry created without explict Node+MappedLUN ACLs
             */
            if (!lacl)
                continue;

            if (explict &&
               (nacl != NULL) && (nacl == lacl->se_lun_nacl) &&
               (l_port != NULL) && (l_port == port))
                continue;

            core_scsi3_ua_allocate(lacl->se_lun_nacl,
                se_deve->mapped_lun, 0x2A,
                ASCQ_2AH_ASYMMETRIC_ACCESS_STATE_CHANGED);
        }
        spin_unlock_bh(&port->sep_alua_lock);

        spin_lock(&tg_pt_gp->tg_pt_gp_lock);
        atomic_dec(&mem->tg_pt_gp_mem_ref_cnt);
        smp_mb__after_atomic_dec();
    }
    spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
    /*
     * Update the ALUA metadata buf that has been allocated in
     * core_alua_do_port_transition(), this metadata will be written
     * to struct file.
     *
     * Note that there is the case where we do not want to update the
     * metadata when the saved metadata is being parsed in userspace
     * when setting the existing port access state and access status.
     *
     * Also note that the failure to write out the ALUA metadata to
     * struct file does NOT affect the actual ALUA transition.
     */
    if (tg_pt_gp->tg_pt_gp_write_metadata) {
        mutex_lock(&tg_pt_gp->tg_pt_gp_md_mutex);
        core_alua_update_tpg_primary_metadata(tg_pt_gp,
                    new_state, md_buf);
        mutex_unlock(&tg_pt_gp->tg_pt_gp_md_mutex);
    }
    /*
     * Set the current primary ALUA access state to the requested new state
     */
    atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state, new_state);

    pr_debug("Successful %s ALUA transition TG PT Group: %s ID: %hu"
        " from primary access state %s to %s\n", (explict) ? "explict" :
        "implict", config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item),
        tg_pt_gp->tg_pt_gp_id, core_alua_dump_state(old_state),
        core_alua_dump_state(new_state));

    return 0;
}

int core_alua_do_port_transition(
    struct t10_alua_tg_pt_gp *l_tg_pt_gp,
    struct se_device *l_dev,
    struct se_port *l_port,
    struct se_node_acl *l_nacl,
    int new_state,
    int explict)
{
    struct se_device *dev;
    struct se_port *port;
    struct se_subsystem_dev *su_dev;
    struct se_node_acl *nacl;
    struct t10_alua_lu_gp *lu_gp;
    struct t10_alua_lu_gp_member *lu_gp_mem, *local_lu_gp_mem;
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    unsigned char *md_buf;
    int primary;

    if (core_alua_check_transition(new_state, &primary) != 0)
        return -EINVAL;

    md_buf = kzalloc(l_tg_pt_gp->tg_pt_gp_md_buf_len, GFP_KERNEL);
    if (!md_buf) {
        pr_err("Unable to allocate buf for ALUA metadata\n");
        return -ENOMEM;
    }

    local_lu_gp_mem = l_dev->dev_alua_lu_gp_mem;
    spin_lock(&local_lu_gp_mem->lu_gp_mem_lock);
    lu_gp = local_lu_gp_mem->lu_gp;
    atomic_inc(&lu_gp->lu_gp_ref_cnt);
    smp_mb__after_atomic_inc();
    spin_unlock(&local_lu_gp_mem->lu_gp_mem_lock);
    /*
     * For storage objects that are members of the 'default_lu_gp',
     * we only do transition on the passed *l_tp_pt_gp, and not
     * on all of the matching target port groups IDs in default_lu_gp.
     */
    if (!lu_gp->lu_gp_id) {
        /*
         * core_alua_do_transition_tg_pt() will always return
         * success.
         */
        core_alua_do_transition_tg_pt(l_tg_pt_gp, l_port, l_nacl,
                    md_buf, new_state, explict);
        atomic_dec(&lu_gp->lu_gp_ref_cnt);
        smp_mb__after_atomic_dec();
        kfree(md_buf);
        return 0;
    }
    /*
     * For all other LU groups aside from 'default_lu_gp', walk all of
     * the associated storage objects looking for a matching target port
     * group ID from the local target port group.
     */
    spin_lock(&lu_gp->lu_gp_lock);
    list_for_each_entry(lu_gp_mem, &lu_gp->lu_gp_mem_list,
                lu_gp_mem_list) {

        dev = lu_gp_mem->lu_gp_mem_dev;
        su_dev = dev->se_sub_dev;
        atomic_inc(&lu_gp_mem->lu_gp_mem_ref_cnt);
        smp_mb__after_atomic_inc();
        spin_unlock(&lu_gp->lu_gp_lock);

        spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
        list_for_each_entry(tg_pt_gp,
                &su_dev->t10_alua.tg_pt_gps_list,
                tg_pt_gp_list) {

            if (!tg_pt_gp->tg_pt_gp_valid_id)
                continue;
            /*
             * If the target behavior port asymmetric access state
             * is changed for any target port group accessiable via
             * a logical unit within a LU group, the target port
             * behavior group asymmetric access states for the same
             * target port group accessible via other logical units
             * in that LU group will also change.
             */
            if (l_tg_pt_gp->tg_pt_gp_id != tg_pt_gp->tg_pt_gp_id)
                continue;

            if (l_tg_pt_gp == tg_pt_gp) {
                port = l_port;
                nacl = l_nacl;
            } else {
                port = NULL;
                nacl = NULL;
            }
            atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
            smp_mb__after_atomic_inc();
            spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
            /*
             * core_alua_do_transition_tg_pt() will always return
             * success.
             */
            core_alua_do_transition_tg_pt(tg_pt_gp, port,
                    nacl, md_buf, new_state, explict);

            spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
            atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
            smp_mb__after_atomic_dec();
        }
        spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);

        spin_lock(&lu_gp->lu_gp_lock);
        atomic_dec(&lu_gp_mem->lu_gp_mem_ref_cnt);
        smp_mb__after_atomic_dec();
    }
    spin_unlock(&lu_gp->lu_gp_lock);

    pr_debug("Successfully processed LU Group: %s all ALUA TG PT"
        " Group IDs: %hu %s transition to primary state: %s\n",
        config_item_name(&lu_gp->lu_gp_group.cg_item),
        l_tg_pt_gp->tg_pt_gp_id, (explict) ? "explict" : "implict",
        core_alua_dump_state(new_state));

    atomic_dec(&lu_gp->lu_gp_ref_cnt);
    smp_mb__after_atomic_dec();
    kfree(md_buf);
    return 0;
}

/*
 * Called with tg_pt_gp_mem->sep_tg_pt_md_mutex held
 */
static int core_alua_update_tpg_secondary_metadata(
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
    struct se_port *port,
    unsigned char *md_buf,
    u32 md_buf_len)
{
    struct se_portal_group *se_tpg = port->sep_tpg;
    char path[ALUA_METADATA_PATH_LEN], wwn[ALUA_SECONDARY_METADATA_WWN_LEN];
    int len;

    memset(path, 0, ALUA_METADATA_PATH_LEN);
    memset(wwn, 0, ALUA_SECONDARY_METADATA_WWN_LEN);

    len = snprintf(wwn, ALUA_SECONDARY_METADATA_WWN_LEN, "%s",
            se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg));

    if (se_tpg->se_tpg_tfo->tpg_get_tag != NULL)
        snprintf(wwn+len, ALUA_SECONDARY_METADATA_WWN_LEN-len, "+%hu",
                se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));

    len = snprintf(md_buf, md_buf_len, "alua_tg_pt_offline=%d\n"
            "alua_tg_pt_status=0x%02x\n",
            atomic_read(&port->sep_tg_pt_secondary_offline),
            port->sep_tg_pt_secondary_stat);

    snprintf(path, ALUA_METADATA_PATH_LEN, "/var/target/alua/%s/%s/lun_%u",
            se_tpg->se_tpg_tfo->get_fabric_name(), wwn,
            port->sep_lun->unpacked_lun);

    return core_alua_write_tpg_metadata(path, md_buf, len);
}

static int core_alua_set_tg_pt_secondary_state(
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
    struct se_port *port,
    int explict,
    int offline)
{
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    unsigned char *md_buf;
    u32 md_buf_len;
    int trans_delay_msecs;

    spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
    if (!tg_pt_gp) {
        spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
        pr_err("Unable to complete secondary state"
                " transition\n");
        return -EINVAL;
    }
    trans_delay_msecs = tg_pt_gp->tg_pt_gp_trans_delay_msecs;
    /*
     * Set the secondary ALUA target port access state to OFFLINE
     * or release the previously secondary state for struct se_port
     */
    if (offline)
        atomic_set(&port->sep_tg_pt_secondary_offline, 1);
    else
        atomic_set(&port->sep_tg_pt_secondary_offline, 0);

    md_buf_len = tg_pt_gp->tg_pt_gp_md_buf_len;
    port->sep_tg_pt_secondary_stat = (explict) ?
            ALUA_STATUS_ALTERED_BY_EXPLICT_STPG :
            ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA;

    pr_debug("Successful %s ALUA transition TG PT Group: %s ID: %hu"
        " to secondary access state: %s\n", (explict) ? "explict" :
        "implict", config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item),
        tg_pt_gp->tg_pt_gp_id, (offline) ? "OFFLINE" : "ONLINE");

    spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    /*
     * Do the optional transition delay after we set the secondary
     * ALUA access state.
     */
    if (trans_delay_msecs != 0)
        msleep_interruptible(trans_delay_msecs);
    /*
     * See if we need to update the ALUA fabric port metadata for
     * secondary state and status
     */
    if (port->sep_tg_pt_secondary_write_md) {
        md_buf = kzalloc(md_buf_len, GFP_KERNEL);
        if (!md_buf) {
            pr_err("Unable to allocate md_buf for"
                " secondary ALUA access metadata\n");
            return -ENOMEM;
        }
        mutex_lock(&port->sep_tg_pt_md_mutex);
        core_alua_update_tpg_secondary_metadata(tg_pt_gp_mem, port,
                md_buf, md_buf_len);
        mutex_unlock(&port->sep_tg_pt_md_mutex);

        kfree(md_buf);
    }

    return 0;
}

struct t10_alua_lu_gp *
core_alua_allocate_lu_gp(const char *name, int def_group)
{
    struct t10_alua_lu_gp *lu_gp;

    lu_gp = kmem_cache_zalloc(t10_alua_lu_gp_cache, GFP_KERNEL);
    if (!lu_gp) {
        pr_err("Unable to allocate struct t10_alua_lu_gp\n");
        return ERR_PTR(-ENOMEM);
    }
    INIT_LIST_HEAD(&lu_gp->lu_gp_node);
    INIT_LIST_HEAD(&lu_gp->lu_gp_mem_list);
    spin_lock_init(&lu_gp->lu_gp_lock);
    atomic_set(&lu_gp->lu_gp_ref_cnt, 0);

    if (def_group) {
        lu_gp->lu_gp_id = alua_lu_gps_counter++;
        lu_gp->lu_gp_valid_id = 1;
        alua_lu_gps_count++;
    }

    return lu_gp;
}

int core_alua_set_lu_gp_id(struct t10_alua_lu_gp *lu_gp, u16 lu_gp_id)
{
    struct t10_alua_lu_gp *lu_gp_tmp;
    u16 lu_gp_id_tmp;
    /*
     * The lu_gp->lu_gp_id may only be set once..
     */
    if (lu_gp->lu_gp_valid_id) {
        pr_warn("ALUA LU Group already has a valid ID,"
            " ignoring request\n");
        return -EINVAL;
    }

    spin_lock(&lu_gps_lock);
    if (alua_lu_gps_count == 0x0000ffff) {
        pr_err("Maximum ALUA alua_lu_gps_count:"
                " 0x0000ffff reached\n");
        spin_unlock(&lu_gps_lock);
        kmem_cache_free(t10_alua_lu_gp_cache, lu_gp);
        return -ENOSPC;
    }
again:
    lu_gp_id_tmp = (lu_gp_id != 0) ? lu_gp_id :
                alua_lu_gps_counter++;

    list_for_each_entry(lu_gp_tmp, &lu_gps_list, lu_gp_node) {
        if (lu_gp_tmp->lu_gp_id == lu_gp_id_tmp) {
            if (!lu_gp_id)
                goto again;

            pr_warn("ALUA Logical Unit Group ID: %hu"
                " already exists, ignoring request\n",
                lu_gp_id);
            spin_unlock(&lu_gps_lock);
            return -EINVAL;
        }
    }

    lu_gp->lu_gp_id = lu_gp_id_tmp;
    lu_gp->lu_gp_valid_id = 1;
    list_add_tail(&lu_gp->lu_gp_node, &lu_gps_list);
    alua_lu_gps_count++;
    spin_unlock(&lu_gps_lock);

    return 0;
}

static struct t10_alua_lu_gp_member *
core_alua_allocate_lu_gp_mem(struct se_device *dev)
{
    struct t10_alua_lu_gp_member *lu_gp_mem;

    lu_gp_mem = kmem_cache_zalloc(t10_alua_lu_gp_mem_cache, GFP_KERNEL);
    if (!lu_gp_mem) {
        pr_err("Unable to allocate struct t10_alua_lu_gp_member\n");
        return ERR_PTR(-ENOMEM);
    }
    INIT_LIST_HEAD(&lu_gp_mem->lu_gp_mem_list);
    spin_lock_init(&lu_gp_mem->lu_gp_mem_lock);
    atomic_set(&lu_gp_mem->lu_gp_mem_ref_cnt, 0);

    lu_gp_mem->lu_gp_mem_dev = dev;
    dev->dev_alua_lu_gp_mem = lu_gp_mem;

    return lu_gp_mem;
}

void core_alua_free_lu_gp(struct t10_alua_lu_gp *lu_gp)
{
    struct t10_alua_lu_gp_member *lu_gp_mem, *lu_gp_mem_tmp;
    /*
     * Once we have reached this point, config_item_put() has
     * already been called from target_core_alua_drop_lu_gp().
     *
     * Here, we remove the *lu_gp from the global list so that
     * no associations can be made while we are releasing
     * struct t10_alua_lu_gp.
     */
    spin_lock(&lu_gps_lock);
    list_del(&lu_gp->lu_gp_node);
    alua_lu_gps_count--;
    spin_unlock(&lu_gps_lock);
    /*
     * Allow struct t10_alua_lu_gp * referenced by core_alua_get_lu_gp_by_name()
     * in target_core_configfs.c:target_core_store_alua_lu_gp() to be
     * released with core_alua_put_lu_gp_from_name()
     */
    while (atomic_read(&lu_gp->lu_gp_ref_cnt))
        cpu_relax();
    /*
     * Release reference to struct t10_alua_lu_gp * from all associated
     * struct se_device.
     */
    spin_lock(&lu_gp->lu_gp_lock);
    list_for_each_entry_safe(lu_gp_mem, lu_gp_mem_tmp,
                &lu_gp->lu_gp_mem_list, lu_gp_mem_list) {
        if (lu_gp_mem->lu_gp_assoc) {
            list_del(&lu_gp_mem->lu_gp_mem_list);
            lu_gp->lu_gp_members--;
            lu_gp_mem->lu_gp_assoc = 0;
        }
        spin_unlock(&lu_gp->lu_gp_lock);
        /*
         *
         * lu_gp_mem is associated with a single
         * struct se_device->dev_alua_lu_gp_mem, and is released when
         * struct se_device is released via core_alua_free_lu_gp_mem().
         *
         * If the passed lu_gp does NOT match the default_lu_gp, assume
         * we want to re-assocate a given lu_gp_mem with default_lu_gp.
         */
        spin_lock(&lu_gp_mem->lu_gp_mem_lock);
        if (lu_gp != default_lu_gp)
            __core_alua_attach_lu_gp_mem(lu_gp_mem,
                    default_lu_gp);
        else
            lu_gp_mem->lu_gp = NULL;
        spin_unlock(&lu_gp_mem->lu_gp_mem_lock);

        spin_lock(&lu_gp->lu_gp_lock);
    }
    spin_unlock(&lu_gp->lu_gp_lock);

    kmem_cache_free(t10_alua_lu_gp_cache, lu_gp);
}

void core_alua_free_lu_gp_mem(struct se_device *dev)
{
    struct se_subsystem_dev *su_dev = dev->se_sub_dev;
    struct t10_alua *alua = &su_dev->t10_alua;
    struct t10_alua_lu_gp *lu_gp;
    struct t10_alua_lu_gp_member *lu_gp_mem;

    if (alua->alua_type != SPC3_ALUA_EMULATED)
        return;

    lu_gp_mem = dev->dev_alua_lu_gp_mem;
    if (!lu_gp_mem)
        return;

    while (atomic_read(&lu_gp_mem->lu_gp_mem_ref_cnt))
        cpu_relax();

    spin_lock(&lu_gp_mem->lu_gp_mem_lock);
    lu_gp = lu_gp_mem->lu_gp;
    if (lu_gp) {
        spin_lock(&lu_gp->lu_gp_lock);
        if (lu_gp_mem->lu_gp_assoc) {
            list_del(&lu_gp_mem->lu_gp_mem_list);
            lu_gp->lu_gp_members--;
            lu_gp_mem->lu_gp_assoc = 0;
        }
        spin_unlock(&lu_gp->lu_gp_lock);
        lu_gp_mem->lu_gp = NULL;
    }
    spin_unlock(&lu_gp_mem->lu_gp_mem_lock);

    kmem_cache_free(t10_alua_lu_gp_mem_cache, lu_gp_mem);
}

struct t10_alua_lu_gp *core_alua_get_lu_gp_by_name(const char *name)
{
    struct t10_alua_lu_gp *lu_gp;
    struct config_item *ci;

    spin_lock(&lu_gps_lock);
    list_for_each_entry(lu_gp, &lu_gps_list, lu_gp_node) {
        if (!lu_gp->lu_gp_valid_id)
            continue;
        ci = &lu_gp->lu_gp_group.cg_item;
        if (!strcmp(config_item_name(ci), name)) {
            atomic_inc(&lu_gp->lu_gp_ref_cnt);
            spin_unlock(&lu_gps_lock);
            return lu_gp;
        }
    }
    spin_unlock(&lu_gps_lock);

    return NULL;
}

void core_alua_put_lu_gp_from_name(struct t10_alua_lu_gp *lu_gp)
{
    spin_lock(&lu_gps_lock);
    atomic_dec(&lu_gp->lu_gp_ref_cnt);
    spin_unlock(&lu_gps_lock);
}

/*
 * Called with struct t10_alua_lu_gp_member->lu_gp_mem_lock
 */
void __core_alua_attach_lu_gp_mem(
    struct t10_alua_lu_gp_member *lu_gp_mem,
    struct t10_alua_lu_gp *lu_gp)
{
    spin_lock(&lu_gp->lu_gp_lock);
    lu_gp_mem->lu_gp = lu_gp;
    lu_gp_mem->lu_gp_assoc = 1;
    list_add_tail(&lu_gp_mem->lu_gp_mem_list, &lu_gp->lu_gp_mem_list);
    lu_gp->lu_gp_members++;
    spin_unlock(&lu_gp->lu_gp_lock);
}

/*
 * Called with struct t10_alua_lu_gp_member->lu_gp_mem_lock
 */
void __core_alua_drop_lu_gp_mem(
    struct t10_alua_lu_gp_member *lu_gp_mem,
    struct t10_alua_lu_gp *lu_gp)
{
    spin_lock(&lu_gp->lu_gp_lock);
    list_del(&lu_gp_mem->lu_gp_mem_list);
    lu_gp_mem->lu_gp = NULL;
    lu_gp_mem->lu_gp_assoc = 0;
    lu_gp->lu_gp_members--;
    spin_unlock(&lu_gp->lu_gp_lock);
}

struct t10_alua_tg_pt_gp *core_alua_allocate_tg_pt_gp(
    struct se_subsystem_dev *su_dev,
    const char *name,
    int def_group)
{
    struct t10_alua_tg_pt_gp *tg_pt_gp;

    tg_pt_gp = kmem_cache_zalloc(t10_alua_tg_pt_gp_cache, GFP_KERNEL);
    if (!tg_pt_gp) {
        pr_err("Unable to allocate struct t10_alua_tg_pt_gp\n");
        return NULL;
    }
    INIT_LIST_HEAD(&tg_pt_gp->tg_pt_gp_list);
    INIT_LIST_HEAD(&tg_pt_gp->tg_pt_gp_mem_list);
    mutex_init(&tg_pt_gp->tg_pt_gp_md_mutex);
    spin_lock_init(&tg_pt_gp->tg_pt_gp_lock);
    atomic_set(&tg_pt_gp->tg_pt_gp_ref_cnt, 0);
    tg_pt_gp->tg_pt_gp_su_dev = su_dev;
    tg_pt_gp->tg_pt_gp_md_buf_len = ALUA_MD_BUF_LEN;
    atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
        ALUA_ACCESS_STATE_ACTIVE_OPTMIZED);
    /*
     * Enable both explict and implict ALUA support by default
     */
    tg_pt_gp->tg_pt_gp_alua_access_type =
            TPGS_EXPLICT_ALUA | TPGS_IMPLICT_ALUA;
    /*
     * Set the default Active/NonOptimized Delay in milliseconds
     */
    tg_pt_gp->tg_pt_gp_nonop_delay_msecs = ALUA_DEFAULT_NONOP_DELAY_MSECS;
    tg_pt_gp->tg_pt_gp_trans_delay_msecs = ALUA_DEFAULT_TRANS_DELAY_MSECS;
    tg_pt_gp->tg_pt_gp_implict_trans_secs = ALUA_DEFAULT_IMPLICT_TRANS_SECS;

    if (def_group) {
        spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
        tg_pt_gp->tg_pt_gp_id =
                su_dev->t10_alua.alua_tg_pt_gps_counter++;
        tg_pt_gp->tg_pt_gp_valid_id = 1;
        su_dev->t10_alua.alua_tg_pt_gps_count++;
        list_add_tail(&tg_pt_gp->tg_pt_gp_list,
                  &su_dev->t10_alua.tg_pt_gps_list);
        spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
    }

    return tg_pt_gp;
}

int core_alua_set_tg_pt_gp_id(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    u16 tg_pt_gp_id)
{
    struct se_subsystem_dev *su_dev = tg_pt_gp->tg_pt_gp_su_dev;
    struct t10_alua_tg_pt_gp *tg_pt_gp_tmp;
    u16 tg_pt_gp_id_tmp;
    /*
     * The tg_pt_gp->tg_pt_gp_id may only be set once..
     */
    if (tg_pt_gp->tg_pt_gp_valid_id) {
        pr_warn("ALUA TG PT Group already has a valid ID,"
            " ignoring request\n");
        return -EINVAL;
    }

    spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
    if (su_dev->t10_alua.alua_tg_pt_gps_count == 0x0000ffff) {
        pr_err("Maximum ALUA alua_tg_pt_gps_count:"
            " 0x0000ffff reached\n");
        spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
        kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
        return -ENOSPC;
    }
again:
    tg_pt_gp_id_tmp = (tg_pt_gp_id != 0) ? tg_pt_gp_id :
            su_dev->t10_alua.alua_tg_pt_gps_counter++;

    list_for_each_entry(tg_pt_gp_tmp, &su_dev->t10_alua.tg_pt_gps_list,
            tg_pt_gp_list) {
        if (tg_pt_gp_tmp->tg_pt_gp_id == tg_pt_gp_id_tmp) {
            if (!tg_pt_gp_id)
                goto again;

            pr_err("ALUA Target Port Group ID: %hu already"
                " exists, ignoring request\n", tg_pt_gp_id);
            spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
            return -EINVAL;
        }
    }

    tg_pt_gp->tg_pt_gp_id = tg_pt_gp_id_tmp;
    tg_pt_gp->tg_pt_gp_valid_id = 1;
    list_add_tail(&tg_pt_gp->tg_pt_gp_list,
            &su_dev->t10_alua.tg_pt_gps_list);
    su_dev->t10_alua.alua_tg_pt_gps_count++;
    spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);

    return 0;
}

struct t10_alua_tg_pt_gp_member *core_alua_allocate_tg_pt_gp_mem(
    struct se_port *port)
{
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;

    tg_pt_gp_mem = kmem_cache_zalloc(t10_alua_tg_pt_gp_mem_cache,
                GFP_KERNEL);
    if (!tg_pt_gp_mem) {
        pr_err("Unable to allocate struct t10_alua_tg_pt_gp_member\n");
        return ERR_PTR(-ENOMEM);
    }
    INIT_LIST_HEAD(&tg_pt_gp_mem->tg_pt_gp_mem_list);
    spin_lock_init(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    atomic_set(&tg_pt_gp_mem->tg_pt_gp_mem_ref_cnt, 0);

    tg_pt_gp_mem->tg_pt = port;
    port->sep_alua_tg_pt_gp_mem = tg_pt_gp_mem;

    return tg_pt_gp_mem;
}

void core_alua_free_tg_pt_gp(
    struct t10_alua_tg_pt_gp *tg_pt_gp)
{
    struct se_subsystem_dev *su_dev = tg_pt_gp->tg_pt_gp_su_dev;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem, *tg_pt_gp_mem_tmp;
    /*
     * Once we have reached this point, config_item_put() has already
     * been called from target_core_alua_drop_tg_pt_gp().
     *
     * Here we remove *tg_pt_gp from the global list so that
     * no assications *OR* explict ALUA via SET_TARGET_PORT_GROUPS
     * can be made while we are releasing struct t10_alua_tg_pt_gp.
     */
    spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
    list_del(&tg_pt_gp->tg_pt_gp_list);
    su_dev->t10_alua.alua_tg_pt_gps_counter--;
    spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
    /*
     * Allow a struct t10_alua_tg_pt_gp_member * referenced by
     * core_alua_get_tg_pt_gp_by_name() in
     * target_core_configfs.c:target_core_store_alua_tg_pt_gp()
     * to be released with core_alua_put_tg_pt_gp_from_name().
     */
    while (atomic_read(&tg_pt_gp->tg_pt_gp_ref_cnt))
        cpu_relax();
    /*
     * Release reference to struct t10_alua_tg_pt_gp from all associated
     * struct se_port.
     */
    spin_lock(&tg_pt_gp->tg_pt_gp_lock);
    list_for_each_entry_safe(tg_pt_gp_mem, tg_pt_gp_mem_tmp,
            &tg_pt_gp->tg_pt_gp_mem_list, tg_pt_gp_mem_list) {
        if (tg_pt_gp_mem->tg_pt_gp_assoc) {
            list_del(&tg_pt_gp_mem->tg_pt_gp_mem_list);
            tg_pt_gp->tg_pt_gp_members--;
            tg_pt_gp_mem->tg_pt_gp_assoc = 0;
        }
        spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
        /*
         * tg_pt_gp_mem is associated with a single
         * se_port->sep_alua_tg_pt_gp_mem, and is released via
         * core_alua_free_tg_pt_gp_mem().
         *
         * If the passed tg_pt_gp does NOT match the default_tg_pt_gp,
         * assume we want to re-assocate a given tg_pt_gp_mem with
         * default_tg_pt_gp.
         */
        spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
        if (tg_pt_gp != su_dev->t10_alua.default_tg_pt_gp) {
            __core_alua_attach_tg_pt_gp_mem(tg_pt_gp_mem,
                    su_dev->t10_alua.default_tg_pt_gp);
        } else
            tg_pt_gp_mem->tg_pt_gp = NULL;
        spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);

        spin_lock(&tg_pt_gp->tg_pt_gp_lock);
    }
    spin_unlock(&tg_pt_gp->tg_pt_gp_lock);

    kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
}

void core_alua_free_tg_pt_gp_mem(struct se_port *port)
{
    struct se_subsystem_dev *su_dev = port->sep_lun->lun_se_dev->se_sub_dev;
    struct t10_alua *alua = &su_dev->t10_alua;
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;

    if (alua->alua_type != SPC3_ALUA_EMULATED)
        return;

    tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
    if (!tg_pt_gp_mem)
        return;

    while (atomic_read(&tg_pt_gp_mem->tg_pt_gp_mem_ref_cnt))
        cpu_relax();

    spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
    if (tg_pt_gp) {
        spin_lock(&tg_pt_gp->tg_pt_gp_lock);
        if (tg_pt_gp_mem->tg_pt_gp_assoc) {
            list_del(&tg_pt_gp_mem->tg_pt_gp_mem_list);
            tg_pt_gp->tg_pt_gp_members--;
            tg_pt_gp_mem->tg_pt_gp_assoc = 0;
        }
        spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
        tg_pt_gp_mem->tg_pt_gp = NULL;
    }
    spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);

    kmem_cache_free(t10_alua_tg_pt_gp_mem_cache, tg_pt_gp_mem);
}

static struct t10_alua_tg_pt_gp *core_alua_get_tg_pt_gp_by_name(
    struct se_subsystem_dev *su_dev,
    const char *name)
{
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    struct config_item *ci;

    spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
    list_for_each_entry(tg_pt_gp, &su_dev->t10_alua.tg_pt_gps_list,
            tg_pt_gp_list) {
        if (!tg_pt_gp->tg_pt_gp_valid_id)
            continue;
        ci = &tg_pt_gp->tg_pt_gp_group.cg_item;
        if (!strcmp(config_item_name(ci), name)) {
            atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
            spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
            return tg_pt_gp;
        }
    }
    spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);

    return NULL;
}

static void core_alua_put_tg_pt_gp_from_name(
    struct t10_alua_tg_pt_gp *tg_pt_gp)
{
    struct se_subsystem_dev *su_dev = tg_pt_gp->tg_pt_gp_su_dev;

    spin_lock(&su_dev->t10_alua.tg_pt_gps_lock);
    atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
    spin_unlock(&su_dev->t10_alua.tg_pt_gps_lock);
}

/*
 * Called with struct t10_alua_tg_pt_gp_member->tg_pt_gp_mem_lock held
 */
void __core_alua_attach_tg_pt_gp_mem(
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
    struct t10_alua_tg_pt_gp *tg_pt_gp)
{
    spin_lock(&tg_pt_gp->tg_pt_gp_lock);
    tg_pt_gp_mem->tg_pt_gp = tg_pt_gp;
    tg_pt_gp_mem->tg_pt_gp_assoc = 1;
    list_add_tail(&tg_pt_gp_mem->tg_pt_gp_mem_list,
            &tg_pt_gp->tg_pt_gp_mem_list);
    tg_pt_gp->tg_pt_gp_members++;
    spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
}

/*
 * Called with struct t10_alua_tg_pt_gp_member->tg_pt_gp_mem_lock held
 */
static void __core_alua_drop_tg_pt_gp_mem(
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
    struct t10_alua_tg_pt_gp *tg_pt_gp)
{
    spin_lock(&tg_pt_gp->tg_pt_gp_lock);
    list_del(&tg_pt_gp_mem->tg_pt_gp_mem_list);
    tg_pt_gp_mem->tg_pt_gp = NULL;
    tg_pt_gp_mem->tg_pt_gp_assoc = 0;
    tg_pt_gp->tg_pt_gp_members--;
    spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
}

ssize_t core_alua_show_tg_pt_gp_info(struct se_port *port, char *page)
{
    struct se_subsystem_dev *su_dev = port->sep_lun->lun_se_dev->se_sub_dev;
    struct config_item *tg_pt_ci;
    struct t10_alua *alua = &su_dev->t10_alua;
    struct t10_alua_tg_pt_gp *tg_pt_gp;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
    ssize_t len = 0;

    if (alua->alua_type != SPC3_ALUA_EMULATED)
        return len;

    tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
    if (!tg_pt_gp_mem)
        return len;

    spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
    if (tg_pt_gp) {
        tg_pt_ci = &tg_pt_gp->tg_pt_gp_group.cg_item;
        len += sprintf(page, "TG Port Alias: %s\nTG Port Group ID:"
            " %hu\nTG Port Primary Access State: %s\nTG Port "
            "Primary Access Status: %s\nTG Port Secondary Access"
            " State: %s\nTG Port Secondary Access Status: %s\n",
            config_item_name(tg_pt_ci), tg_pt_gp->tg_pt_gp_id,
            core_alua_dump_state(atomic_read(
                    &tg_pt_gp->tg_pt_gp_alua_access_state)),
            core_alua_dump_status(
                tg_pt_gp->tg_pt_gp_alua_access_status),
            (atomic_read(&port->sep_tg_pt_secondary_offline)) ?
            "Offline" : "None",
            core_alua_dump_status(port->sep_tg_pt_secondary_stat));
    }
    spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);

    return len;
}

ssize_t core_alua_store_tg_pt_gp_info(
    struct se_port *port,
    const char *page,
    size_t count)
{
    struct se_portal_group *tpg;
    struct se_lun *lun;
    struct se_subsystem_dev *su_dev = port->sep_lun->lun_se_dev->se_sub_dev;
    struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *tg_pt_gp_new = NULL;
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
    unsigned char buf[TG_PT_GROUP_NAME_BUF];
    int move = 0;

    tpg = port->sep_tpg;
    lun = port->sep_lun;

    if (su_dev->t10_alua.alua_type != SPC3_ALUA_EMULATED) {
        pr_warn("SPC3_ALUA_EMULATED not enabled for"
            " %s/tpgt_%hu/%s\n", tpg->se_tpg_tfo->tpg_get_wwn(tpg),
            tpg->se_tpg_tfo->tpg_get_tag(tpg),
            config_item_name(&lun->lun_group.cg_item));
        return -EINVAL;
    }

    if (count > TG_PT_GROUP_NAME_BUF) {
        pr_err("ALUA Target Port Group alias too large!\n");
        return -EINVAL;
    }
    memset(buf, 0, TG_PT_GROUP_NAME_BUF);
    memcpy(buf, page, count);
    /*
     * Any ALUA target port group alias besides "NULL" means we will be
     * making a new group association.
     */
    if (strcmp(strstrip(buf), "NULL")) {
        /*
         * core_alua_get_tg_pt_gp_by_name() will increment reference to
         * struct t10_alua_tg_pt_gp.  This reference is released with
         * core_alua_put_tg_pt_gp_from_name() below.
         */
        tg_pt_gp_new = core_alua_get_tg_pt_gp_by_name(su_dev,
                    strstrip(buf));
        if (!tg_pt_gp_new)
            return -ENODEV;
    }
    tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
    if (!tg_pt_gp_mem) {
        if (tg_pt_gp_new)
            core_alua_put_tg_pt_gp_from_name(tg_pt_gp_new);
        pr_err("NULL struct se_port->sep_alua_tg_pt_gp_mem pointer\n");
        return -EINVAL;
    }

    spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
    if (tg_pt_gp) {
        /*
         * Clearing an existing tg_pt_gp association, and replacing
         * with the default_tg_pt_gp.
         */
        if (!tg_pt_gp_new) {
            pr_debug("Target_Core_ConfigFS: Moving"
                " %s/tpgt_%hu/%s from ALUA Target Port Group:"
                " alua/%s, ID: %hu back to"
                " default_tg_pt_gp\n",
                tpg->se_tpg_tfo->tpg_get_wwn(tpg),
                tpg->se_tpg_tfo->tpg_get_tag(tpg),
                config_item_name(&lun->lun_group.cg_item),
                config_item_name(
                    &tg_pt_gp->tg_pt_gp_group.cg_item),
                tg_pt_gp->tg_pt_gp_id);

            __core_alua_drop_tg_pt_gp_mem(tg_pt_gp_mem, tg_pt_gp);
            __core_alua_attach_tg_pt_gp_mem(tg_pt_gp_mem,
                    su_dev->t10_alua.default_tg_pt_gp);
            spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);

            return count;
        }
        /*
         * Removing existing association of tg_pt_gp_mem with tg_pt_gp
         */
        __core_alua_drop_tg_pt_gp_mem(tg_pt_gp_mem, tg_pt_gp);
        move = 1;
    }
    /*
     * Associate tg_pt_gp_mem with tg_pt_gp_new.
     */
    __core_alua_attach_tg_pt_gp_mem(tg_pt_gp_mem, tg_pt_gp_new);
    spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
    pr_debug("Target_Core_ConfigFS: %s %s/tpgt_%hu/%s to ALUA"
        " Target Port Group: alua/%s, ID: %hu\n", (move) ?
        "Moving" : "Adding", tpg->se_tpg_tfo->tpg_get_wwn(tpg),
        tpg->se_tpg_tfo->tpg_get_tag(tpg),
        config_item_name(&lun->lun_group.cg_item),
        config_item_name(&tg_pt_gp_new->tg_pt_gp_group.cg_item),
        tg_pt_gp_new->tg_pt_gp_id);

    core_alua_put_tg_pt_gp_from_name(tg_pt_gp_new);
    return count;
}

ssize_t core_alua_show_access_type(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    char *page)
{
    if ((tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA) &&
        (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_IMPLICT_ALUA))
        return sprintf(page, "Implict and Explict\n");
    else if (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_IMPLICT_ALUA)
        return sprintf(page, "Implict\n");
    else if (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA)
        return sprintf(page, "Explict\n");
    else
        return sprintf(page, "None\n");
}

ssize_t core_alua_store_access_type(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract alua_access_type\n");
        return -EINVAL;
    }
    if ((tmp != 0) && (tmp != 1) && (tmp != 2) && (tmp != 3)) {
        pr_err("Illegal value for alua_access_type:"
                " %lu\n", tmp);
        return -EINVAL;
    }
    if (tmp == 3)
        tg_pt_gp->tg_pt_gp_alua_access_type =
            TPGS_IMPLICT_ALUA | TPGS_EXPLICT_ALUA;
    else if (tmp == 2)
        tg_pt_gp->tg_pt_gp_alua_access_type = TPGS_EXPLICT_ALUA;
    else if (tmp == 1)
        tg_pt_gp->tg_pt_gp_alua_access_type = TPGS_IMPLICT_ALUA;
    else
        tg_pt_gp->tg_pt_gp_alua_access_type = 0;

    return count;
}

ssize_t core_alua_show_nonop_delay_msecs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    char *page)
{
    return sprintf(page, "%d\n", tg_pt_gp->tg_pt_gp_nonop_delay_msecs);
}

ssize_t core_alua_store_nonop_delay_msecs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract nonop_delay_msecs\n");
        return -EINVAL;
    }
    if (tmp > ALUA_MAX_NONOP_DELAY_MSECS) {
        pr_err("Passed nonop_delay_msecs: %lu, exceeds"
            " ALUA_MAX_NONOP_DELAY_MSECS: %d\n", tmp,
            ALUA_MAX_NONOP_DELAY_MSECS);
        return -EINVAL;
    }
    tg_pt_gp->tg_pt_gp_nonop_delay_msecs = (int)tmp;

    return count;
}

ssize_t core_alua_show_trans_delay_msecs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    char *page)
{
    return sprintf(page, "%d\n", tg_pt_gp->tg_pt_gp_trans_delay_msecs);
}

ssize_t core_alua_store_trans_delay_msecs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract trans_delay_msecs\n");
        return -EINVAL;
    }
    if (tmp > ALUA_MAX_TRANS_DELAY_MSECS) {
        pr_err("Passed trans_delay_msecs: %lu, exceeds"
            " ALUA_MAX_TRANS_DELAY_MSECS: %d\n", tmp,
            ALUA_MAX_TRANS_DELAY_MSECS);
        return -EINVAL;
    }
    tg_pt_gp->tg_pt_gp_trans_delay_msecs = (int)tmp;

    return count;
}

ssize_t core_alua_show_implict_trans_secs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    char *page)
{
    return sprintf(page, "%d\n", tg_pt_gp->tg_pt_gp_implict_trans_secs);
}

ssize_t core_alua_store_implict_trans_secs(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract implict_trans_secs\n");
        return -EINVAL;
    }
    if (tmp > ALUA_MAX_IMPLICT_TRANS_SECS) {
        pr_err("Passed implict_trans_secs: %lu, exceeds"
            " ALUA_MAX_IMPLICT_TRANS_SECS: %d\n", tmp,
            ALUA_MAX_IMPLICT_TRANS_SECS);
        return  -EINVAL;
    }
    tg_pt_gp->tg_pt_gp_implict_trans_secs = (int)tmp;

    return count;
}

ssize_t core_alua_show_preferred_bit(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    char *page)
{
    return sprintf(page, "%d\n", tg_pt_gp->tg_pt_gp_pref);
}

ssize_t core_alua_store_preferred_bit(
    struct t10_alua_tg_pt_gp *tg_pt_gp,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract preferred ALUA value\n");
        return -EINVAL;
    }
    if ((tmp != 0) && (tmp != 1)) {
        pr_err("Illegal value for preferred ALUA: %lu\n", tmp);
        return -EINVAL;
    }
    tg_pt_gp->tg_pt_gp_pref = (int)tmp;

    return count;
}

ssize_t core_alua_show_offline_bit(struct se_lun *lun, char *page)
{
    if (!lun->lun_sep)
        return -ENODEV;

    return sprintf(page, "%d\n",
        atomic_read(&lun->lun_sep->sep_tg_pt_secondary_offline));
}

ssize_t core_alua_store_offline_bit(
    struct se_lun *lun,
    const char *page,
    size_t count)
{
    struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
    unsigned long tmp;
    int ret;

    if (!lun->lun_sep)
        return -ENODEV;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract alua_tg_pt_offline value\n");
        return -EINVAL;
    }
    if ((tmp != 0) && (tmp != 1)) {
        pr_err("Illegal value for alua_tg_pt_offline: %lu\n",
                tmp);
        return -EINVAL;
    }
    tg_pt_gp_mem = lun->lun_sep->sep_alua_tg_pt_gp_mem;
    if (!tg_pt_gp_mem) {
        pr_err("Unable to locate *tg_pt_gp_mem\n");
        return -EINVAL;
    }

    ret = core_alua_set_tg_pt_secondary_state(tg_pt_gp_mem,
            lun->lun_sep, 0, (int)tmp);
    if (ret < 0)
        return -EINVAL;

    return count;
}

ssize_t core_alua_show_secondary_status(
    struct se_lun *lun,
    char *page)
{
    return sprintf(page, "%d\n", lun->lun_sep->sep_tg_pt_secondary_stat);
}

ssize_t core_alua_store_secondary_status(
    struct se_lun *lun,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract alua_tg_pt_status\n");
        return -EINVAL;
    }
    if ((tmp != ALUA_STATUS_NONE) &&
        (tmp != ALUA_STATUS_ALTERED_BY_EXPLICT_STPG) &&
        (tmp != ALUA_STATUS_ALTERED_BY_IMPLICT_ALUA)) {
        pr_err("Illegal value for alua_tg_pt_status: %lu\n",
                tmp);
        return -EINVAL;
    }
    lun->lun_sep->sep_tg_pt_secondary_stat = (int)tmp;

    return count;
}

ssize_t core_alua_show_secondary_write_metadata(
    struct se_lun *lun,
    char *page)
{
    return sprintf(page, "%d\n",
            lun->lun_sep->sep_tg_pt_secondary_write_md);
}

ssize_t core_alua_store_secondary_write_metadata(
    struct se_lun *lun,
    const char *page,
    size_t count)
{
    unsigned long tmp;
    int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        pr_err("Unable to extract alua_tg_pt_write_md\n");
        return -EINVAL;
    }
    if ((tmp != 0) && (tmp != 1)) {
        pr_err("Illegal value for alua_tg_pt_write_md:"
                " %lu\n", tmp);
        return -EINVAL;
    }
    lun->lun_sep->sep_tg_pt_secondary_write_md = (int)tmp;

    return count;
}

int core_setup_alua(struct se_device *dev, int force_pt)
{
    struct se_subsystem_dev *su_dev = dev->se_sub_dev;
    struct t10_alua *alua = &su_dev->t10_alua;
    struct t10_alua_lu_gp_member *lu_gp_mem;
    /*
     * If this device is from Target_Core_Mod/pSCSI, use the ALUA logic
     * of the Underlying SCSI hardware.  In Linux/SCSI terms, this can
     * cause a problem because libata and some SATA RAID HBAs appear
     * under Linux/SCSI, but emulate SCSI logic themselves.
     */
    if (((dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV) &&
        !(dev->se_sub_dev->se_dev_attrib.emulate_alua)) || force_pt) {
        alua->alua_type = SPC_ALUA_PASSTHROUGH;
        alua->alua_state_check = &core_alua_state_check_nop;
        pr_debug("%s: Using SPC_ALUA_PASSTHROUGH, no ALUA"
            " emulation\n", dev->transport->name);
        return 0;
    }
    /*
     * If SPC-3 or above is reported by real or emulated struct se_device,
     * use emulated ALUA.
     */
    if (dev->transport->get_device_rev(dev) >= SCSI_3) {
        pr_debug("%s: Enabling ALUA Emulation for SPC-3"
            " device\n", dev->transport->name);
        /*
         * Associate this struct se_device with the default ALUA
         * LUN Group.
         */
        lu_gp_mem = core_alua_allocate_lu_gp_mem(dev);
        if (IS_ERR(lu_gp_mem))
            return PTR_ERR(lu_gp_mem);

        alua->alua_type = SPC3_ALUA_EMULATED;
        alua->alua_state_check = &core_alua_state_check;
        spin_lock(&lu_gp_mem->lu_gp_mem_lock);
        __core_alua_attach_lu_gp_mem(lu_gp_mem,
                default_lu_gp);
        spin_unlock(&lu_gp_mem->lu_gp_mem_lock);

        pr_debug("%s: Adding to default ALUA LU Group:"
            " core/alua/lu_gps/default_lu_gp\n",
            dev->transport->name);
    } else {
        alua->alua_type = SPC2_ALUA_DISABLED;
        alua->alua_state_check = &core_alua_state_check_nop;
        pr_debug("%s: Disabling ALUA Emulation for SPC-2"
            " device\n", dev->transport->name);
    }

    return 0;
}