/*******************************************************************************
   * 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 <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/slab.h>
  #include <linux/spinlock.h>
  #include <linux/configfs.h>

  #include <linux/export.h>

  #include <scsi/scsi.h>
  #include <scsi/scsi_cmnd.h>
  
  #include <target/target_core_base.h>
  #include <target/target_core_device.h>
  #include <target/target_core_transport.h>
  #include <target/target_core_fabric_ops.h>
  #include <target/target_core_configfs.h>
  
  #include "target_core_alua.h"
  #include "target_core_hba.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_task *task)

  {

  	struct se_cmd *cmd = task->task_se_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 = 4; /* Skip over RESERVED area to first
  				    Target port group descriptor */

  	/*
  	 * Need at least 4 bytes of response data or else we can't
  	 * even fit the return data length.
  	 */
  	if (cmd->data_length < 4) {
  		pr_warn("REPORT TARGET PORT GROUPS allocation length %u"
  			" too small
  ", cmd->data_length);
  		return -EINVAL;
  	}

  	buf = transport_kmap_first_data_page(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
  	 */
  	buf[0] = ((rd_len >> 24) & 0xff);
  	buf[1] = ((rd_len >> 16) & 0xff);
  	buf[2] = ((rd_len >> 8) & 0xff);
  	buf[3] = (rd_len & 0xff);

  	transport_kunmap_first_data_page(cmd);

  	task->task_scsi_status = GOOD;
  	transport_complete_task(task, 1);

  	return 0;
  }
  
  /*
   * SET_TARGET_PORT_GROUPS for explict ALUA operation.
   *
   * See spc4r17 section 6.35
   */

  int target_emulate_set_target_port_groups(struct se_task *task)

  {

  	struct se_cmd *cmd = task->task_se_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;
  	}

  	buf = transport_kmap_first_data_page(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
  ");

  		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
  ");

  		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
  ");

  		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 = ((ptr[2] << 8) & 0xff);
  			tg_pt_id |= (ptr[3] & 0xff);
  			/*
  			 * 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 = ((ptr[2] << 8) & 0xff);
  			rtpi |= (ptr[3] & 0xff);
  			/*
  			 * Locate the matching relative target port identifer
  			 * 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_first_data_page(cmd);

  	task->task_scsi_status = GOOD;
  	transport_complete_task(task, 1);

  	return 0;
  }
  
  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]) {
  		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]) {
  		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]) {
  		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
  ");
  		*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
  ",

  				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
  ", 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
  ",

  			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
  ", 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
  "
  			"alua_access_state=0x%02x
  "
  			"alua_access_status=0x%02x
  ",
  			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
  ", (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
  ");

  		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
  ",
  		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
  "
  			"alua_tg_pt_status=0x%02x
  ",
  			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
  ");

  		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
  ", (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
  ");

  			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
  ");

  		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
  ");

  		return -EINVAL;

  	}

  	spin_lock(&lu_gps_lock);
  	if (alua_lu_gps_count == 0x0000ffff) {

  		pr_err("Maximum ALUA alua_lu_gps_count:"

  				" 0x0000ffff reached
  ");

  		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
  ",
  				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
  ");

  		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
  ");

  		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;
  
  	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
  ");

  		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
  ");

  		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
  ", 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
  ");

  		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
  TG Port Group ID:"
  			" %hu
  TG Port Primary Access State: %s
  TG Port "
  			"Primary Access Status: %s
  TG Port Secondary Access"
  			" State: %s
  TG Port Secondary Access Status: %s
  ",
  			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
  ", 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!
  ");

  		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
  ");

  		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
  ",

  				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
  ", (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
  ");
  	else if (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_IMPLICT_ALUA)
  		return sprintf(page, "Implict
  ");
  	else if (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA)
  		return sprintf(page, "Explict
  ");
  	else
  		return sprintf(page, "None
  ");
  }
  
  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
  ");

  		return -EINVAL;
  	}
  	if ((tmp != 0) && (tmp != 1) && (tmp != 2) && (tmp != 3)) {

  		pr_err("Illegal value for alua_access_type:"

  				" %lu
  ", 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
  ", 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
  ");

  		return -EINVAL;
  	}
  	if (tmp > ALUA_MAX_NONOP_DELAY_MSECS) {

  		pr_err("Passed nonop_delay_msecs: %lu, exceeds"

  			" ALUA_MAX_NONOP_DELAY_MSECS: %d
  ", 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
  ", 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
  ");

  		return -EINVAL;
  	}
  	if (tmp > ALUA_MAX_TRANS_DELAY_MSECS) {

  		pr_err("Passed trans_delay_msecs: %lu, exceeds"

  			" ALUA_MAX_TRANS_DELAY_MSECS: %d
  ", 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_preferred_bit(
  	struct t10_alua_tg_pt_gp *tg_pt_gp,
  	char *page)
  {
  	return sprintf(page, "%d
  ", 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
  ");

  		return -EINVAL;
  	}
  	if ((tmp != 0) && (tmp != 1)) {

  		pr_err("Illegal value for preferred ALUA: %lu
  ", 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
  ",
  		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
  ");

  		return -EINVAL;
  	}
  	if ((tmp != 0) && (tmp != 1)) {

  		pr_err("Illegal value for alua_tg_pt_offline: %lu
  ",

  				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
  ");

  		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
  ", 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
  ");

  		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
  ",

  				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
  ",
  			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
  ");

  		return -EINVAL;
  	}
  	if ((tmp != 0) && (tmp != 1)) {

  		pr_err("Illegal value for alua_tg_pt_write_md:"

  				" %lu
  ", 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
  ", 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
  ", 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
  ",

  			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
  ", dev->transport->name);

  	}
  
  	return 0;
  }