/*******************************************************************************
 * Filename:  target_core_pr.c
 *
 * This file contains SPC-3 compliant persistent reservations and
 * legacy SPC-2 reservations with compatible reservation handling (CRH=1)
 *
 * 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/list.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_pr.h"
#include "target_core_ua.h"

/*
 * Used for Specify Initiator Ports Capable Bit (SPEC_I_PT)
 */
struct pr_transport_id_holder {
        int dest_local_nexus;
        struct t10_pr_registration *dest_pr_reg;
        struct se_portal_group *dest_tpg;
        struct se_node_acl *dest_node_acl;
        struct se_dev_entry *dest_se_deve;
        struct list_head dest_list;
};

int core_pr_dump_initiator_port(
        struct t10_pr_registration *pr_reg,
        char *buf,
        u32 size)
{
        if (!pr_reg->isid_present_at_reg)
                return 0;

        snprintf(buf, size, ",i,0x%s", &pr_reg->pr_reg_isid[0]);
        return 1;
}

static void __core_scsi3_complete_pro_release(struct se_device *, struct se_node_acl *,
                        struct t10_pr_registration *, int);

static int core_scsi2_reservation_seq_non_holder(
        struct se_cmd *cmd,
        unsigned char *cdb,
        u32 pr_reg_type)
{
        switch (cdb[0]) {
        case INQUIRY:
        case RELEASE:
        case RELEASE_10:
                return 0;
        default:
                return 1;
        }

        return 1;
}

static int core_scsi2_reservation_check(struct se_cmd *cmd, u32 *pr_reg_type)
{
        struct se_device *dev = cmd->se_dev;
        struct se_session *sess = cmd->se_sess;
        int ret;

        if (!sess)
                return 0;

        spin_lock(&dev->dev_reservation_lock);
        if (!dev->dev_reserved_node_acl || !sess) {
                spin_unlock(&dev->dev_reservation_lock);
                return 0;
        }
        if (dev->dev_reserved_node_acl != sess->se_node_acl) {
                spin_unlock(&dev->dev_reservation_lock);
                return -EINVAL;
        }
        if (!(dev->dev_flags & DF_SPC2_RESERVATIONS_WITH_ISID)) {
                spin_unlock(&dev->dev_reservation_lock);
                return 0;
        }
        ret = (dev->dev_res_bin_isid == sess->sess_bin_isid) ? 0 : -EINVAL;
        spin_unlock(&dev->dev_reservation_lock);

        return ret;
}

static struct t10_pr_registration *core_scsi3_locate_pr_reg(struct se_device *,
                                        struct se_node_acl *, struct se_session *);
static void core_scsi3_put_pr_reg(struct t10_pr_registration *);

static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd)
{
        struct se_session *se_sess = cmd->se_sess;
        struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
        struct t10_pr_registration *pr_reg;
        struct t10_reservation *pr_tmpl = &su_dev->t10_pr;
        int crh = (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS);
        int conflict = 0;

        if (!crh)
                return -EINVAL;

        pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev, se_sess->se_node_acl,
                        se_sess);
        if (pr_reg) {
                /*
                 * From spc4r17 5.7.3 Exceptions to SPC-2 RESERVE and RELEASE
                 * behavior
                 *
                 * A RESERVE(6) or RESERVE(10) command shall complete with GOOD
                 * status, but no reservation shall be established and the
                 * persistent reservation shall not be changed, if the command
                 * is received from a) and b) below.
                 *
                 * A RELEASE(6) or RELEASE(10) command shall complete with GOOD
                 * status, but the persistent reservation shall not be released,
                 * if the command is received from a) and b)
                 *
                 * a) An I_T nexus that is a persistent reservation holder; or
                 * b) An I_T nexus that is registered if a registrants only or
                 *    all registrants type persistent reservation is present.
                 *
                 * In all other cases, a RESERVE(6) command, RESERVE(10) command,
                 * RELEASE(6) command, or RELEASE(10) command shall be processed
                 * as defined in SPC-2.
                 */
                if (pr_reg->pr_res_holder) {
                        core_scsi3_put_pr_reg(pr_reg);
                        return 1;
                }
                if ((pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY) ||
                    (pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY) ||
                    (pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
                    (pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG)) {
                        core_scsi3_put_pr_reg(pr_reg);
                        return 1;
                }
                core_scsi3_put_pr_reg(pr_reg);
                conflict = 1;
        } else {
                /*
                 * Following spc2r20 5.5.1 Reservations overview:
                 *
                 * If a logical unit has executed a PERSISTENT RESERVE OUT
                 * command with the REGISTER or the REGISTER AND IGNORE
                 * EXISTING KEY service action and is still registered by any
                 * initiator, all RESERVE commands and all RELEASE commands
                 * regardless of initiator shall conflict and shall terminate
                 * with a RESERVATION CONFLICT status.
                 */
                spin_lock(&pr_tmpl->registration_lock);
                conflict = (list_empty(&pr_tmpl->registration_list)) ? 0 : 1;
                spin_unlock(&pr_tmpl->registration_lock);
        }

        if (conflict) {
                pr_err("Received legacy SPC-2 RESERVE/RELEASE"
                        " while active SPC-3 registrations exist,"
                        " returning RESERVATION_CONFLICT\n");
                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
                return -EBUSY;
        }

        return 0;
}

int target_scsi2_reservation_release(struct se_task *task)
{
        struct se_cmd *cmd = task->task_se_cmd;
        struct se_device *dev = cmd->se_dev;
        struct se_session *sess = cmd->se_sess;
        struct se_portal_group *tpg = sess->se_tpg;
        int ret = 0, rc;

        if (!sess || !tpg)
                goto out;
        rc = target_check_scsi2_reservation_conflict(cmd);
        if (rc == 1)
                goto out;
        else if (rc < 0) {
                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
                ret = -EINVAL;
                goto out;
        }

        ret = 0;
        spin_lock(&dev->dev_reservation_lock);
        if (!dev->dev_reserved_node_acl || !sess)
                goto out_unlock;

        if (dev->dev_reserved_node_acl != sess->se_node_acl)
                goto out_unlock;

        dev->dev_reserved_node_acl = NULL;
        dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
        if (dev->dev_flags & DF_SPC2_RESERVATIONS_WITH_ISID) {
                dev->dev_res_bin_isid = 0;
                dev->dev_flags &= ~DF_SPC2_RESERVATIONS_WITH_ISID;
        }
        pr_debug("SCSI-2 Released reservation for %s LUN: %u ->"
                " MAPPED LUN: %u for %s\n", tpg->se_tpg_tfo->get_fabric_name(),
                cmd->se_lun->unpacked_lun, cmd->se_deve->mapped_lun,
                sess->se_node_acl->initiatorname);

out_unlock:
        spin_unlock(&dev->dev_reservation_lock);
out:
        if (!ret) {
                task->task_scsi_status = GOOD;
                transport_complete_task(task, 1);
        }
        return ret;
}

int target_scsi2_reservation_reserve(struct se_task *task)
{
        struct se_cmd *cmd = task->task_se_cmd;
        struct se_device *dev = cmd->se_dev;
        struct se_session *sess = cmd->se_sess;
        struct se_portal_group *tpg = sess->se_tpg;
        int ret = 0, rc;

        if ((cmd->t_task_cdb[1] & 0x01) &&
            (cmd->t_task_cdb[1] & 0x02)) {
                pr_err("LongIO and Obselete Bits set, returning"
                                " ILLEGAL_REQUEST\n");
                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
                ret = -EINVAL;
                goto out;
        }
        /*
         * This is currently the case for target_core_mod passthrough struct se_cmd
         * ops
         */
        if (!sess || !tpg)
                goto out;
        rc = target_check_scsi2_reservation_conflict(cmd);
        if (rc == 1)
                goto out;
        else if (rc < 0) {
                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
                ret = -EINVAL;
                goto out;
        }

        ret = 0;
        spin_lock(&dev->dev_reservation_lock);
        if (dev->dev_reserved_node_acl &&
           (dev->dev_reserved_node_acl != sess->se_node_acl)) {
                pr_err("SCSI-2 RESERVATION CONFLIFT for %s fabric\n",
                        tpg->se_tpg_tfo->get_fabric_name());
                pr_err("Original reserver LUN: %u %s\n",
                        cmd->se_lun->unpacked_lun,
                        dev->dev_reserved_node_acl->initiatorname);
                pr_err("Current attempt - LUN: %u -> MAPPED LUN: %u"
                        " from %s \n", cmd->se_lun->unpacked_lun,
                        cmd->se_deve->mapped_lun,
                        sess->se_node_acl->initiatorname);
                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
                ret = -EINVAL;
                goto out_unlock;
        }

        dev->dev_reserved_node_acl = sess->se_node_acl;
        dev->dev_flags |= DF_SPC2_RESERVATIONS;
        if (sess->sess_bin_isid != 0) {
                dev->dev_res_bin_isid = sess->sess_bin_isid;
                dev->dev_flags |= DF_SPC2_RESERVATIONS_WITH_ISID;
        }
        pr_debug("SCSI-2 Reserved %s LUN: %u -> MAPPED LUN: %u"
                " for %s\n", tpg->se_tpg_tfo->get_fabric_name(),
                cmd->se_lun->unpacked_lun, cmd->se_deve->mapped_lun,
                sess->se_node_acl->initiatorname);

out_unlock:
        spin_unlock(&dev->dev_reservation_lock);
out:
        if (!ret) {
                task->task_scsi_status = GOOD;
                transport_complete_task(task, 1);
        }
        return ret;
}


/*
 * Begin SPC-3/SPC-4 Persistent Reservations emulation support
 *
 * This function is called by those initiator ports who are *NOT*
 * the active PR reservation holder when a reservation is present.
 */
static int core_scsi3_pr_seq_non_holder(
        struct se_cmd *cmd,
        unsigned char *cdb,
        u32 pr_reg_type)
{
        struct se_dev_entry *se_deve;
        struct se_session *se_sess = cmd->se_sess;
        int other_cdb = 0, ignore_reg;
        int registered_nexus = 0, ret = 1; /* Conflict by default */
        int all_reg = 0, reg_only = 0; /* ALL_REG, REG_ONLY */
        int we = 0; /* Write Exclusive */
        int legacy = 0; /* Act like a legacy device and return
                         * RESERVATION CONFLICT on some CDBs */
        /*
         * A legacy SPC-2 reservation is being held.
         */
        if (cmd->se_dev->dev_flags & DF_SPC2_RESERVATIONS)
                return core_scsi2_reservation_seq_non_holder(cmd,
                                        cdb, pr_reg_type);

        se_deve = &se_sess->se_node_acl->device_list[cmd->orig_fe_lun];
        /*
         * Determine if the registration should be ignored due to
         * non-matching ISIDs in core_scsi3_pr_reservation_check().
         */
        ignore_reg = (pr_reg_type & 0x80000000);
        if (ignore_reg)
                pr_reg_type &= ~0x80000000;

        switch (pr_reg_type) {
        case PR_TYPE_WRITE_EXCLUSIVE:
                we = 1;
        case PR_TYPE_EXCLUSIVE_ACCESS:
                /*
                 * Some commands are only allowed for the persistent reservation
                 * holder.
                 */
                if ((se_deve->def_pr_registered) && !(ignore_reg))
                        registered_nexus = 1;
                break;
        case PR_TYPE_WRITE_EXCLUSIVE_REGONLY:
                we = 1;
        case PR_TYPE_EXCLUSIVE_ACCESS_REGONLY:
                /*
                 * Some commands are only allowed for registered I_T Nexuses.
                 */
                reg_only = 1;
                if ((se_deve->def_pr_registered) && !(ignore_reg))
                        registered_nexus = 1;
                break;
        case PR_TYPE_WRITE_EXCLUSIVE_ALLREG:
                we = 1;
        case PR_TYPE_EXCLUSIVE_ACCESS_ALLREG:
                /*
                 * Each registered I_T Nexus is a reservation holder.
                 */
                all_reg = 1;
                if ((se_deve->def_pr_registered) && !(ignore_reg))
                        registered_nexus = 1;
                break;
        default:
                return -EINVAL;
        }
        /*
         * Referenced from spc4r17 table 45 for *NON* PR holder access
         */
        switch (cdb[0]) {
        case SECURITY_PROTOCOL_IN:
                if (registered_nexus)
                        return 0;
                ret = (we) ? 0 : 1;
                break;
        case MODE_SENSE:
        case MODE_SENSE_10:
        case READ_ATTRIBUTE:
        case READ_BUFFER:
        case RECEIVE_DIAGNOSTIC:
                if (legacy) {
                        ret = 1;
                        break;
                }
                if (registered_nexus) {
                        ret = 0;
                        break;
                }
                ret = (we) ? 0 : 1; /* Allowed Write Exclusive */
                break;
        case PERSISTENT_RESERVE_OUT:
                /*
                 * This follows PERSISTENT_RESERVE_OUT service actions that
                 * are allowed in the presence of various reservations.
                 * See spc4r17, table 46
                 */
                switch (cdb[1] & 0x1f) {
                case PRO_CLEAR:
                case PRO_PREEMPT:
                case PRO_PREEMPT_AND_ABORT:
                        ret = (registered_nexus) ? 0 : 1;
                        break;
                case PRO_REGISTER:
                case PRO_REGISTER_AND_IGNORE_EXISTING_KEY:
                        ret = 0;
                        break;
                case PRO_REGISTER_AND_MOVE:
                case PRO_RESERVE:
                        ret = 1;
                        break;
                case PRO_RELEASE:
                        ret = (registered_nexus) ? 0 : 1;
                        break;
                default:
                        pr_err("Unknown PERSISTENT_RESERVE_OUT service"
                                " action: 0x%02x\n", cdb[1] & 0x1f);
                        return -EINVAL;
                }
                break;
        case RELEASE:
        case RELEASE_10:
                /* Handled by CRH=1 in target_scsi2_reservation_release() */
                ret = 0;
                break;
        case RESERVE:
        case RESERVE_10:
                /* Handled by CRH=1 in target_scsi2_reservation_reserve() */
                ret = 0;
                break;
        case TEST_UNIT_READY:
                ret = (legacy) ? 1 : 0; /* Conflict for legacy */
                break;
        case MAINTENANCE_IN:
                switch (cdb[1] & 0x1f) {
                case MI_MANAGEMENT_PROTOCOL_IN:
                        if (registered_nexus) {
                                ret = 0;
                                break;
                        }
                        ret = (we) ? 0 : 1; /* Allowed Write Exclusive */
                        break;
                case MI_REPORT_SUPPORTED_OPERATION_CODES:
                case MI_REPORT_SUPPORTED_TASK_MANAGEMENT_FUNCTIONS:
                        if (legacy) {
                                ret = 1;
                                break;
                        }
                        if (registered_nexus) {
                                ret = 0;
                                break;
                        }
                        ret = (we) ? 0 : 1; /* Allowed Write Exclusive */
                        break;
                case MI_REPORT_ALIASES:
                case MI_REPORT_IDENTIFYING_INFORMATION:
                case MI_REPORT_PRIORITY:
                case MI_REPORT_TARGET_PGS:
                case MI_REPORT_TIMESTAMP:
                        ret = 0; /* Allowed */
                        break;
                default:
                        pr_err("Unknown MI Service Action: 0x%02x\n",
                                (cdb[1] & 0x1f));
                        return -EINVAL;
                }
                break;
        case ACCESS_CONTROL_IN:
        case ACCESS_CONTROL_OUT:
        case INQUIRY:
        case LOG_SENSE:
        case READ_MEDIA_SERIAL_NUMBER:
        case REPORT_LUNS:
        case REQUEST_SENSE:
        case PERSISTENT_RESERVE_IN:
                ret = 0; /*/ Allowed CDBs */
                break;
        default:
                other_cdb = 1;
                break;
        }
        /*
         * Case where the CDB is explicitly allowed in the above switch
         * statement.
         */
        if (!ret && !other_cdb) {
#if 0
                pr_debug("Allowing explict CDB: 0x%02x for %s"
                        " reservation holder\n", cdb[0],
                        core_scsi3_pr_dump_type(pr_reg_type));
#endif
                return ret;
        }
        /*
         * Check if write exclusive initiator ports *NOT* holding the
         * WRITE_EXCLUSIVE_* reservation.
         */
        if ((we) && !(registered_nexus)) {
                if (cmd->data_direction == DMA_TO_DEVICE) {
                        /*
                         * Conflict for write exclusive
                         */
                        pr_debug("%s Conflict for unregistered nexus"
                                " %s CDB: 0x%02x to %s reservation\n",
                                transport_dump_cmd_direction(cmd),
                                se_sess->se_node_acl->initiatorname, cdb[0],
                                core_scsi3_pr_dump_type(pr_reg_type));
                        return 1;
                } else {
                        /*
                         * Allow non WRITE CDBs for all Write Exclusive
                         * PR TYPEs to pass for registered and
                         * non-registered_nexuxes NOT holding the reservation.
                         *
                         * We only make noise for the unregisterd nexuses,
                         * as we expect registered non-reservation holding
                         * nexuses to issue CDBs.
                         */
#if 0
                        if (!registered_nexus) {
                                pr_debug("Allowing implict CDB: 0x%02x"
                                        " for %s reservation on unregistered"
                                        " nexus\n", cdb[0],
                                        core_scsi3_pr_dump_type(pr_reg_type));
                        }
#endif
                        return 0;
                }
        } else if ((reg_only) || (all_reg)) {
                if (registered_nexus) {
                        /*
                         * For PR_*_REG_ONLY and PR_*_ALL_REG reservations,
                         * allow commands from registered nexuses.
                         */
#if 0
                        pr_debug("Allowing implict CDB: 0x%02x for %s"
                                " reservation\n", cdb[0],
                                core_scsi3_pr_dump_type(pr_reg_type));
#endif
                        return 0;
                }
        }
        pr_debug("%s Conflict for %sregistered nexus %s CDB: 0x%2x"
                " for %s reservation\n", transport_dump_cmd_direction(cmd),
                (registered_nexus) ? "" : "un",
                se_sess->se_node_acl->initiatorname, cdb[0],
                core_scsi3_pr_dump_type(pr_reg_type));

        return 1; /* Conflict by default */
}

static u32 core_scsi3_pr_generation(struct se_device *dev)
{
        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        u32 prg;
        /*
         * PRGeneration field shall contain the value of a 32-bit wrapping
         * counter mainted by the device server.
         *
         * Note that this is done regardless of Active Persist across
         * Target PowerLoss (APTPL)
         *
         * See spc4r17 section 6.3.12 READ_KEYS service action
         */
        spin_lock(&dev->dev_reservation_lock);
        prg = su_dev->t10_pr.pr_generation++;
        spin_unlock(&dev->dev_reservation_lock);

        return prg;
}

static int core_scsi3_pr_reservation_check(
        struct se_cmd *cmd,
        u32 *pr_reg_type)
{
        struct se_device *dev = cmd->se_dev;
        struct se_session *sess = cmd->se_sess;
        int ret;

        if (!sess)
                return 0;
        /*
         * A legacy SPC-2 reservation is being held.
         */
        if (dev->dev_flags & DF_SPC2_RESERVATIONS)
                return core_scsi2_reservation_check(cmd, pr_reg_type);

        spin_lock(&dev->dev_reservation_lock);
        if (!dev->dev_pr_res_holder) {
                spin_unlock(&dev->dev_reservation_lock);
                return 0;
        }
        *pr_reg_type = dev->dev_pr_res_holder->pr_res_type;
        cmd->pr_res_key = dev->dev_pr_res_holder->pr_res_key;
        if (dev->dev_pr_res_holder->pr_reg_nacl != sess->se_node_acl) {
                spin_unlock(&dev->dev_reservation_lock);
                return -EINVAL;
        }
        if (!dev->dev_pr_res_holder->isid_present_at_reg) {
                spin_unlock(&dev->dev_reservation_lock);
                return 0;
        }
        ret = (dev->dev_pr_res_holder->pr_reg_bin_isid ==
               sess->sess_bin_isid) ? 0 : -EINVAL;
        /*
         * Use bit in *pr_reg_type to notify ISID mismatch in
         * core_scsi3_pr_seq_non_holder().
         */
        if (ret != 0)
                *pr_reg_type |= 0x80000000;
        spin_unlock(&dev->dev_reservation_lock);

        return ret;
}

static struct t10_pr_registration *__core_scsi3_do_alloc_registration(
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct se_dev_entry *deve,
        unsigned char *isid,
        u64 sa_res_key,
        int all_tg_pt,
        int aptpl)
{
        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        struct t10_pr_registration *pr_reg;

        pr_reg = kmem_cache_zalloc(t10_pr_reg_cache, GFP_ATOMIC);
        if (!pr_reg) {
                pr_err("Unable to allocate struct t10_pr_registration\n");
                return NULL;
        }

        pr_reg->pr_aptpl_buf = kzalloc(su_dev->t10_pr.pr_aptpl_buf_len,
                                        GFP_ATOMIC);
        if (!pr_reg->pr_aptpl_buf) {
                pr_err("Unable to allocate pr_reg->pr_aptpl_buf\n");
                kmem_cache_free(t10_pr_reg_cache, pr_reg);
                return NULL;
        }

        INIT_LIST_HEAD(&pr_reg->pr_reg_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_abort_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_aptpl_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_atp_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_atp_mem_list);
        atomic_set(&pr_reg->pr_res_holders, 0);
        pr_reg->pr_reg_nacl = nacl;
        pr_reg->pr_reg_deve = deve;
        pr_reg->pr_res_mapped_lun = deve->mapped_lun;
        pr_reg->pr_aptpl_target_lun = deve->se_lun->unpacked_lun;
        pr_reg->pr_res_key = sa_res_key;
        pr_reg->pr_reg_all_tg_pt = all_tg_pt;
        pr_reg->pr_reg_aptpl = aptpl;
        pr_reg->pr_reg_tg_pt_lun = deve->se_lun;
        /*
         * If an ISID value for this SCSI Initiator Port exists,
         * save it to the registration now.
         */
        if (isid != NULL) {
                pr_reg->pr_reg_bin_isid = get_unaligned_be64(isid);
                snprintf(pr_reg->pr_reg_isid, PR_REG_ISID_LEN, "%s", isid);
                pr_reg->isid_present_at_reg = 1;
        }

        return pr_reg;
}

static int core_scsi3_lunacl_depend_item(struct se_dev_entry *);
static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *);

/*
 * Function used for handling PR registrations for ALL_TG_PT=1 and ALL_TG_PT=0
 * modes.
 */
static struct t10_pr_registration *__core_scsi3_alloc_registration(
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct se_dev_entry *deve,
        unsigned char *isid,
        u64 sa_res_key,
        int all_tg_pt,
        int aptpl)
{
        struct se_dev_entry *deve_tmp;
        struct se_node_acl *nacl_tmp;
        struct se_port *port, *port_tmp;
        struct target_core_fabric_ops *tfo = nacl->se_tpg->se_tpg_tfo;
        struct t10_pr_registration *pr_reg, *pr_reg_atp, *pr_reg_tmp, *pr_reg_tmp_safe;
        int ret;
        /*
         * Create a registration for the I_T Nexus upon which the
         * PROUT REGISTER was received.
         */
        pr_reg = __core_scsi3_do_alloc_registration(dev, nacl, deve, isid,
                        sa_res_key, all_tg_pt, aptpl);
        if (!pr_reg)
                return NULL;
        /*
         * Return pointer to pr_reg for ALL_TG_PT=0
         */
        if (!all_tg_pt)
                return pr_reg;
        /*
         * Create list of matching SCSI Initiator Port registrations
         * for ALL_TG_PT=1
         */
        spin_lock(&dev->se_port_lock);
        list_for_each_entry_safe(port, port_tmp, &dev->dev_sep_list, sep_list) {
                atomic_inc(&port->sep_tg_pt_ref_cnt);
                smp_mb__after_atomic_inc();
                spin_unlock(&dev->se_port_lock);

                spin_lock_bh(&port->sep_alua_lock);
                list_for_each_entry(deve_tmp, &port->sep_alua_list,
                                        alua_port_list) {
                        /*
                         * This pointer will be NULL for demo mode MappedLUNs
                         * that have not been make explict via a ConfigFS
                         * MappedLUN group for the SCSI Initiator Node ACL.
                         */
                        if (!deve_tmp->se_lun_acl)
                                continue;

                        nacl_tmp = deve_tmp->se_lun_acl->se_lun_nacl;
                        /*
                         * Skip the matching struct se_node_acl that is allocated
                         * above..
                         */
                        if (nacl == nacl_tmp)
                                continue;
                        /*
                         * Only perform PR registrations for target ports on
                         * the same fabric module as the REGISTER w/ ALL_TG_PT=1
                         * arrived.
                         */
                        if (tfo != nacl_tmp->se_tpg->se_tpg_tfo)
                                continue;
                        /*
                         * Look for a matching Initiator Node ACL in ASCII format
                         */
                        if (strcmp(nacl->initiatorname, nacl_tmp->initiatorname))
                                continue;

                        atomic_inc(&deve_tmp->pr_ref_count);
                        smp_mb__after_atomic_inc();
                        spin_unlock_bh(&port->sep_alua_lock);
                        /*
                         * Grab a configfs group dependency that is released
                         * for the exception path at label out: below, or upon
                         * completion of adding ALL_TG_PT=1 registrations in
                         * __core_scsi3_add_registration()
                         */
                        ret = core_scsi3_lunacl_depend_item(deve_tmp);
                        if (ret < 0) {
                                pr_err("core_scsi3_lunacl_depend"
                                                "_item() failed\n");
                                atomic_dec(&port->sep_tg_pt_ref_cnt);
                                smp_mb__after_atomic_dec();
                                atomic_dec(&deve_tmp->pr_ref_count);
                                smp_mb__after_atomic_dec();
                                goto out;
                        }
                        /*
                         * Located a matching SCSI Initiator Port on a different
                         * port, allocate the pr_reg_atp and attach it to the
                         * pr_reg->pr_reg_atp_list that will be processed once
                         * the original *pr_reg is processed in
                         * __core_scsi3_add_registration()
                         */
                        pr_reg_atp = __core_scsi3_do_alloc_registration(dev,
                                                nacl_tmp, deve_tmp, NULL,
                                                sa_res_key, all_tg_pt, aptpl);
                        if (!pr_reg_atp) {
                                atomic_dec(&port->sep_tg_pt_ref_cnt);
                                smp_mb__after_atomic_dec();
                                atomic_dec(&deve_tmp->pr_ref_count);
                                smp_mb__after_atomic_dec();
                                core_scsi3_lunacl_undepend_item(deve_tmp);
                                goto out;
                        }

                        list_add_tail(&pr_reg_atp->pr_reg_atp_mem_list,
                                      &pr_reg->pr_reg_atp_list);
                        spin_lock_bh(&port->sep_alua_lock);
                }
                spin_unlock_bh(&port->sep_alua_lock);

                spin_lock(&dev->se_port_lock);
                atomic_dec(&port->sep_tg_pt_ref_cnt);
                smp_mb__after_atomic_dec();
        }
        spin_unlock(&dev->se_port_lock);

        return pr_reg;
out:
        list_for_each_entry_safe(pr_reg_tmp, pr_reg_tmp_safe,
                        &pr_reg->pr_reg_atp_list, pr_reg_atp_mem_list) {
                list_del(&pr_reg_tmp->pr_reg_atp_mem_list);
                core_scsi3_lunacl_undepend_item(pr_reg_tmp->pr_reg_deve);
                kmem_cache_free(t10_pr_reg_cache, pr_reg_tmp);
        }
        kmem_cache_free(t10_pr_reg_cache, pr_reg);
        return NULL;
}

int core_scsi3_alloc_aptpl_registration(
        struct t10_reservation *pr_tmpl,
        u64 sa_res_key,
        unsigned char *i_port,
        unsigned char *isid,
        u32 mapped_lun,
        unsigned char *t_port,
        u16 tpgt,
        u32 target_lun,
        int res_holder,
        int all_tg_pt,
        u8 type)
{
        struct t10_pr_registration *pr_reg;

        if (!i_port || !t_port || !sa_res_key) {
                pr_err("Illegal parameters for APTPL registration\n");
                return -EINVAL;
        }

        pr_reg = kmem_cache_zalloc(t10_pr_reg_cache, GFP_KERNEL);
        if (!pr_reg) {
                pr_err("Unable to allocate struct t10_pr_registration\n");
                return -ENOMEM;
        }
        pr_reg->pr_aptpl_buf = kzalloc(pr_tmpl->pr_aptpl_buf_len, GFP_KERNEL);

        INIT_LIST_HEAD(&pr_reg->pr_reg_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_abort_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_aptpl_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_atp_list);
        INIT_LIST_HEAD(&pr_reg->pr_reg_atp_mem_list);
        atomic_set(&pr_reg->pr_res_holders, 0);
        pr_reg->pr_reg_nacl = NULL;
        pr_reg->pr_reg_deve = NULL;
        pr_reg->pr_res_mapped_lun = mapped_lun;
        pr_reg->pr_aptpl_target_lun = target_lun;
        pr_reg->pr_res_key = sa_res_key;
        pr_reg->pr_reg_all_tg_pt = all_tg_pt;
        pr_reg->pr_reg_aptpl = 1;
        pr_reg->pr_reg_tg_pt_lun = NULL;
        pr_reg->pr_res_scope = 0; /* Always LUN_SCOPE */
        pr_reg->pr_res_type = type;
        /*
         * If an ISID value had been saved in APTPL metadata for this
         * SCSI Initiator Port, restore it now.
         */
        if (isid != NULL) {
                pr_reg->pr_reg_bin_isid = get_unaligned_be64(isid);
                snprintf(pr_reg->pr_reg_isid, PR_REG_ISID_LEN, "%s", isid);
                pr_reg->isid_present_at_reg = 1;
        }
        /*
         * Copy the i_port and t_port information from caller.
         */
        snprintf(pr_reg->pr_iport, PR_APTPL_MAX_IPORT_LEN, "%s", i_port);
        snprintf(pr_reg->pr_tport, PR_APTPL_MAX_TPORT_LEN, "%s", t_port);
        pr_reg->pr_reg_tpgt = tpgt;
        /*
         * Set pr_res_holder from caller, the pr_reg who is the reservation
         * holder will get it's pointer set in core_scsi3_aptpl_reserve() once
         * the Initiator Node LUN ACL from the fabric module is created for
         * this registration.
         */
        pr_reg->pr_res_holder = res_holder;

        list_add_tail(&pr_reg->pr_reg_aptpl_list, &pr_tmpl->aptpl_reg_list);
        pr_debug("SPC-3 PR APTPL Successfully added registration%s from"
                        " metadata\n", (res_holder) ? "+reservation" : "");
        return 0;
}

static void core_scsi3_aptpl_reserve(
        struct se_device *dev,
        struct se_portal_group *tpg,
        struct se_node_acl *node_acl,
        struct t10_pr_registration *pr_reg)
{
        char i_buf[PR_REG_ISID_ID_LEN];
        int prf_isid;

        memset(i_buf, 0, PR_REG_ISID_ID_LEN);
        prf_isid = core_pr_dump_initiator_port(pr_reg, &i_buf[0],
                                PR_REG_ISID_ID_LEN);

        spin_lock(&dev->dev_reservation_lock);
        dev->dev_pr_res_holder = pr_reg;
        spin_unlock(&dev->dev_reservation_lock);

        pr_debug("SPC-3 PR [%s] Service Action: APTPL RESERVE created"
                " new reservation holder TYPE: %s ALL_TG_PT: %d\n",
                tpg->se_tpg_tfo->get_fabric_name(),
                core_scsi3_pr_dump_type(pr_reg->pr_res_type),
                (pr_reg->pr_reg_all_tg_pt) ? 1 : 0);
        pr_debug("SPC-3 PR [%s] RESERVE Node: %s%s\n",
                tpg->se_tpg_tfo->get_fabric_name(), node_acl->initiatorname,
                (prf_isid) ? &i_buf[0] : "");
}

static void __core_scsi3_add_registration(struct se_device *, struct se_node_acl *,
                                struct t10_pr_registration *, int, int);

static int __core_scsi3_check_aptpl_registration(
        struct se_device *dev,
        struct se_portal_group *tpg,
        struct se_lun *lun,
        u32 target_lun,
        struct se_node_acl *nacl,
        struct se_dev_entry *deve)
{
        struct t10_pr_registration *pr_reg, *pr_reg_tmp;
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
        unsigned char i_port[PR_APTPL_MAX_IPORT_LEN];
        unsigned char t_port[PR_APTPL_MAX_TPORT_LEN];
        u16 tpgt;

        memset(i_port, 0, PR_APTPL_MAX_IPORT_LEN);
        memset(t_port, 0, PR_APTPL_MAX_TPORT_LEN);
        /*
         * Copy Initiator Port information from struct se_node_acl
         */
        snprintf(i_port, PR_APTPL_MAX_IPORT_LEN, "%s", nacl->initiatorname);
        snprintf(t_port, PR_APTPL_MAX_TPORT_LEN, "%s",
                        tpg->se_tpg_tfo->tpg_get_wwn(tpg));
        tpgt = tpg->se_tpg_tfo->tpg_get_tag(tpg);
        /*
         * Look for the matching registrations+reservation from those
         * created from APTPL metadata.  Note that multiple registrations
         * may exist for fabrics that use ISIDs in their SCSI Initiator Port
         * TransportIDs.
         */
        spin_lock(&pr_tmpl->aptpl_reg_lock);
        list_for_each_entry_safe(pr_reg, pr_reg_tmp, &pr_tmpl->aptpl_reg_list,
                                pr_reg_aptpl_list) {
                if (!strcmp(pr_reg->pr_iport, i_port) &&
                     (pr_reg->pr_res_mapped_lun == deve->mapped_lun) &&
                    !(strcmp(pr_reg->pr_tport, t_port)) &&
                     (pr_reg->pr_reg_tpgt == tpgt) &&
                     (pr_reg->pr_aptpl_target_lun == target_lun)) {

                        pr_reg->pr_reg_nacl = nacl;
                        pr_reg->pr_reg_deve = deve;
                        pr_reg->pr_reg_tg_pt_lun = lun;

                        list_del(&pr_reg->pr_reg_aptpl_list);
                        spin_unlock(&pr_tmpl->aptpl_reg_lock);
                        /*
                         * At this point all of the pointers in *pr_reg will
                         * be setup, so go ahead and add the registration.
                         */

                        __core_scsi3_add_registration(dev, nacl, pr_reg, 0, 0);
                        /*
                         * If this registration is the reservation holder,
                         * make that happen now..
                         */
                        if (pr_reg->pr_res_holder)
                                core_scsi3_aptpl_reserve(dev, tpg,
                                                nacl, pr_reg);
                        /*
                         * Reenable pr_aptpl_active to accept new metadata
                         * updates once the SCSI device is active again..
                         */
                        spin_lock(&pr_tmpl->aptpl_reg_lock);
                        pr_tmpl->pr_aptpl_active = 1;
                }
        }
        spin_unlock(&pr_tmpl->aptpl_reg_lock);

        return 0;
}

int core_scsi3_check_aptpl_registration(
        struct se_device *dev,
        struct se_portal_group *tpg,
        struct se_lun *lun,
        struct se_lun_acl *lun_acl)
{

        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        struct se_node_acl *nacl = lun_acl->se_lun_nacl;
        struct se_dev_entry *deve = &nacl->device_list[lun_acl->mapped_lun];

        if (su_dev->t10_pr.res_type != SPC3_PERSISTENT_RESERVATIONS)
                return 0;

        return __core_scsi3_check_aptpl_registration(dev, tpg, lun,
                                lun->unpacked_lun, nacl, deve);
}

static void __core_scsi3_dump_registration(
        struct target_core_fabric_ops *tfo,
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct t10_pr_registration *pr_reg,
        int register_type)
{
        struct se_portal_group *se_tpg = nacl->se_tpg;
        char i_buf[PR_REG_ISID_ID_LEN];
        int prf_isid;

        memset(&i_buf[0], 0, PR_REG_ISID_ID_LEN);
        prf_isid = core_pr_dump_initiator_port(pr_reg, &i_buf[0],
                                PR_REG_ISID_ID_LEN);

        pr_debug("SPC-3 PR [%s] Service Action: REGISTER%s Initiator"
                " Node: %s%s\n", tfo->get_fabric_name(), (register_type == 2) ?
                "_AND_MOVE" : (register_type == 1) ?
                "_AND_IGNORE_EXISTING_KEY" : "", nacl->initiatorname,
                (prf_isid) ? i_buf : "");
        pr_debug("SPC-3 PR [%s] registration on Target Port: %s,0x%04x\n",
                 tfo->get_fabric_name(), tfo->tpg_get_wwn(se_tpg),
                tfo->tpg_get_tag(se_tpg));
        pr_debug("SPC-3 PR [%s] for %s TCM Subsystem %s Object Target"
                " Port(s)\n",  tfo->get_fabric_name(),
                (pr_reg->pr_reg_all_tg_pt) ? "ALL" : "SINGLE",
                dev->transport->name);
        pr_debug("SPC-3 PR [%s] SA Res Key: 0x%016Lx PRgeneration:"
                " 0x%08x  APTPL: %d\n", tfo->get_fabric_name(),
                pr_reg->pr_res_key, pr_reg->pr_res_generation,
                pr_reg->pr_reg_aptpl);
}

/*
 * this function can be called with struct se_device->dev_reservation_lock
 * when register_move = 1
 */
static void __core_scsi3_add_registration(
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct t10_pr_registration *pr_reg,
        int register_type,
        int register_move)
{
        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        struct target_core_fabric_ops *tfo = nacl->se_tpg->se_tpg_tfo;
        struct t10_pr_registration *pr_reg_tmp, *pr_reg_tmp_safe;
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;

        /*
         * Increment PRgeneration counter for struct se_device upon a successful
         * REGISTER, see spc4r17 section 6.3.2 READ_KEYS service action
         *
         * Also, when register_move = 1 for PROUT REGISTER_AND_MOVE service
         * action, the struct se_device->dev_reservation_lock will already be held,
         * so we do not call core_scsi3_pr_generation() which grabs the lock
         * for the REGISTER.
         */
        pr_reg->pr_res_generation = (register_move) ?
                        su_dev->t10_pr.pr_generation++ :
                        core_scsi3_pr_generation(dev);

        spin_lock(&pr_tmpl->registration_lock);
        list_add_tail(&pr_reg->pr_reg_list, &pr_tmpl->registration_list);
        pr_reg->pr_reg_deve->def_pr_registered = 1;

        __core_scsi3_dump_registration(tfo, dev, nacl, pr_reg, register_type);
        spin_unlock(&pr_tmpl->registration_lock);
        /*
         * Skip extra processing for ALL_TG_PT=0 or REGISTER_AND_MOVE.
         */
        if (!pr_reg->pr_reg_all_tg_pt || register_move)
                return;
        /*
         * Walk pr_reg->pr_reg_atp_list and add registrations for ALL_TG_PT=1
         * allocated in __core_scsi3_alloc_registration()
         */
        list_for_each_entry_safe(pr_reg_tmp, pr_reg_tmp_safe,
                        &pr_reg->pr_reg_atp_list, pr_reg_atp_mem_list) {
                list_del(&pr_reg_tmp->pr_reg_atp_mem_list);

                pr_reg_tmp->pr_res_generation = core_scsi3_pr_generation(dev);

                spin_lock(&pr_tmpl->registration_lock);
                list_add_tail(&pr_reg_tmp->pr_reg_list,
                              &pr_tmpl->registration_list);
                pr_reg_tmp->pr_reg_deve->def_pr_registered = 1;

                __core_scsi3_dump_registration(tfo, dev,
                                pr_reg_tmp->pr_reg_nacl, pr_reg_tmp,
                                register_type);
                spin_unlock(&pr_tmpl->registration_lock);
                /*
                 * Drop configfs group dependency reference from
                 * __core_scsi3_alloc_registration()
                 */
                core_scsi3_lunacl_undepend_item(pr_reg_tmp->pr_reg_deve);
        }
}

static int core_scsi3_alloc_registration(
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct se_dev_entry *deve,
        unsigned char *isid,
        u64 sa_res_key,
        int all_tg_pt,
        int aptpl,
        int register_type,
        int register_move)
{
        struct t10_pr_registration *pr_reg;

        pr_reg = __core_scsi3_alloc_registration(dev, nacl, deve, isid,
                        sa_res_key, all_tg_pt, aptpl);
        if (!pr_reg)
                return -EPERM;

        __core_scsi3_add_registration(dev, nacl, pr_reg,
                        register_type, register_move);
        return 0;
}

static struct t10_pr_registration *__core_scsi3_locate_pr_reg(
        struct se_device *dev,
        struct se_node_acl *nacl,
        unsigned char *isid)
{
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
        struct t10_pr_registration *pr_reg, *pr_reg_tmp;
        struct se_portal_group *tpg;

        spin_lock(&pr_tmpl->registration_lock);
        list_for_each_entry_safe(pr_reg, pr_reg_tmp,
                        &pr_tmpl->registration_list, pr_reg_list) {
                /*
                 * First look for a matching struct se_node_acl
                 */
                if (pr_reg->pr_reg_nacl != nacl)
                        continue;

                tpg = pr_reg->pr_reg_nacl->se_tpg;
                /*
                 * If this registration does NOT contain a fabric provided
                 * ISID, then we have found a match.
                 */
                if (!pr_reg->isid_present_at_reg) {
                        /*
                         * Determine if this SCSI device server requires that
                         * SCSI Intiatior TransportID w/ ISIDs is enforced
                         * for fabric modules (iSCSI) requiring them.
                         */
                        if (tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
                                if (dev->se_sub_dev->se_dev_attrib.enforce_pr_isids)
                                        continue;
                        }
                        atomic_inc(&pr_reg->pr_res_holders);
                        smp_mb__after_atomic_inc();
                        spin_unlock(&pr_tmpl->registration_lock);
                        return pr_reg;
                }
                /*
                 * If the *pr_reg contains a fabric defined ISID for multi-value
                 * SCSI Initiator Port TransportIDs, then we expect a valid
                 * matching ISID to be provided by the local SCSI Initiator Port.
                 */
                if (!isid)
                        continue;
                if (strcmp(isid, pr_reg->pr_reg_isid))
                        continue;

                atomic_inc(&pr_reg->pr_res_holders);
                smp_mb__after_atomic_inc();
                spin_unlock(&pr_tmpl->registration_lock);
                return pr_reg;
        }
        spin_unlock(&pr_tmpl->registration_lock);

        return NULL;
}

static struct t10_pr_registration *core_scsi3_locate_pr_reg(
        struct se_device *dev,
        struct se_node_acl *nacl,
        struct se_session *sess)
{
        struct se_portal_group *tpg = nacl->se_tpg;
        unsigned char buf[PR_REG_ISID_LEN], *isid_ptr = NULL;

        if (tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
                memset(&buf[0], 0, PR_REG_ISID_LEN);
                tpg->se_tpg_tfo->sess_get_initiator_sid(sess, &buf[0],
                                        PR_REG_ISID_LEN);
                isid_ptr = &buf[0];
        }

        return __core_scsi3_locate_pr_reg(dev, nacl, isid_ptr);
}

static void core_scsi3_put_pr_reg(struct t10_pr_registration *pr_reg)
{
        atomic_dec(&pr_reg->pr_res_holders);
        smp_mb__after_atomic_dec();
}

static int core_scsi3_check_implict_release(
        struct se_device *dev,
        struct t10_pr_registration *pr_reg)
{
        struct se_node_acl *nacl = pr_reg->pr_reg_nacl;
        struct t10_pr_registration *pr_res_holder;
        int ret = 0;

        spin_lock(&dev->dev_reservation_lock);
        pr_res_holder = dev->dev_pr_res_holder;
        if (!pr_res_holder) {
                spin_unlock(&dev->dev_reservation_lock);
                return ret;
        }
        if (pr_res_holder == pr_reg) {
                /*
                 * Perform an implict RELEASE if the registration that
                 * is being released is holding the reservation.
                 *
                 * From spc4r17, section 5.7.11.1:
                 *
                 * e) If the I_T nexus is the persistent reservation holder
                 *    and the persistent reservation is not an all registrants
                 *    type, then a PERSISTENT RESERVE OUT command with REGISTER
                 *    service action or REGISTER AND  IGNORE EXISTING KEY
                 *    service action with the SERVICE ACTION RESERVATION KEY
                 *    field set to zero (see 5.7.11.3).
                 */
                __core_scsi3_complete_pro_release(dev, nacl, pr_reg, 0);
                ret = 1;
                /*
                 * For 'All Registrants' reservation types, all existing
                 * registrations are still processed as reservation holders
                 * in core_scsi3_pr_seq_non_holder() after the initial
                 * reservation holder is implictly released here.
                 */
        } else if (pr_reg->pr_reg_all_tg_pt &&
                  (!strcmp(pr_res_holder->pr_reg_nacl->initiatorname,
                          pr_reg->pr_reg_nacl->initiatorname)) &&
                  (pr_res_holder->pr_res_key == pr_reg->pr_res_key)) {
                pr_err("SPC-3 PR: Unable to perform ALL_TG_PT=1"
                        " UNREGISTER while existing reservation with matching"
                        " key 0x%016Lx is present from another SCSI Initiator"
                        " Port\n", pr_reg->pr_res_key);
                ret = -EPERM;
        }
        spin_unlock(&dev->dev_reservation_lock);

        return ret;
}

/*
 * Called with struct t10_reservation->registration_lock held.
 */
static void __core_scsi3_free_registration(
        struct se_device *dev,
        struct t10_pr_registration *pr_reg,
        struct list_head *preempt_and_abort_list,
        int dec_holders)
{
        struct target_core_fabric_ops *tfo =
                        pr_reg->pr_reg_nacl->se_tpg->se_tpg_tfo;
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
        char i_buf[PR_REG_ISID_ID_LEN];
        int prf_isid;

        memset(i_buf, 0, PR_REG_ISID_ID_LEN);
        prf_isid = core_pr_dump_initiator_port(pr_reg, &i_buf[0],
                                PR_REG_ISID_ID_LEN);

        pr_reg->pr_reg_deve->def_pr_registered = 0;
        pr_reg->pr_reg_deve->pr_res_key = 0;
        list_del(&pr_reg->pr_reg_list);
        /*
         * Caller accessing *pr_reg using core_scsi3_locate_pr_reg(),
         * so call core_scsi3_put_pr_reg() to decrement our reference.
         */
        if (dec_holders)
                core_scsi3_put_pr_reg(pr_reg);
        /*
         * Wait until all reference from any other I_T nexuses for this
         * *pr_reg have been released.  Because list_del() is called above,
         * the last core_scsi3_put_pr_reg(pr_reg) will release this reference
         * count back to zero, and we release *pr_reg.
         */
        while (atomic_read(&pr_reg->pr_res_holders) != 0) {
                spin_unlock(&pr_tmpl->registration_lock);
                pr_debug("SPC-3 PR [%s] waiting for pr_res_holders\n",
                                tfo->get_fabric_name());
                cpu_relax();
                spin_lock(&pr_tmpl->registration_lock);
        }

        pr_debug("SPC-3 PR [%s] Service Action: UNREGISTER Initiator"
                " Node: %s%s\n", tfo->get_fabric_name(),
                pr_reg->pr_reg_nacl->initiatorname,
                (prf_isid) ? &i_buf[0] : "");
        pr_debug("SPC-3 PR [%s] for %s TCM Subsystem %s Object Target"
                " Port(s)\n", tfo->get_fabric_name(),
                (pr_reg->pr_reg_all_tg_pt) ? "ALL" : "SINGLE",
                dev->transport->name);
        pr_debug("SPC-3 PR [%s] SA Res Key: 0x%016Lx PRgeneration:"
                " 0x%08x\n", tfo->get_fabric_name(), pr_reg->pr_res_key,
                pr_reg->pr_res_generation);

        if (!preempt_and_abort_list) {
                pr_reg->pr_reg_deve = NULL;
                pr_reg->pr_reg_nacl = NULL;
                kfree(pr_reg->pr_aptpl_buf);
                kmem_cache_free(t10_pr_reg_cache, pr_reg);
                return;
        }
        /*
         * For PREEMPT_AND_ABORT, the list of *pr_reg in preempt_and_abort_list
         * are released once the ABORT_TASK_SET has completed..
         */
        list_add_tail(&pr_reg->pr_reg_abort_list, preempt_and_abort_list);
}

void core_scsi3_free_pr_reg_from_nacl(
        struct se_device *dev,
        struct se_node_acl *nacl)
{
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
        struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_res_holder;
        /*
         * If the passed se_node_acl matches the reservation holder,
         * release the reservation.
         */
        spin_lock(&dev->dev_reservation_lock);
        pr_res_holder = dev->dev_pr_res_holder;
        if ((pr_res_holder != NULL) &&
            (pr_res_holder->pr_reg_nacl == nacl))
                __core_scsi3_complete_pro_release(dev, nacl, pr_res_holder, 0);
        spin_unlock(&dev->dev_reservation_lock);
        /*
         * Release any registration associated with the struct se_node_acl.
         */
        spin_lock(&pr_tmpl->registration_lock);
        list_for_each_entry_safe(pr_reg, pr_reg_tmp,
                        &pr_tmpl->registration_list, pr_reg_list) {

                if (pr_reg->pr_reg_nacl != nacl)
                        continue;

                __core_scsi3_free_registration(dev, pr_reg, NULL, 0);
        }
        spin_unlock(&pr_tmpl->registration_lock);
}

void core_scsi3_free_all_registrations(
        struct se_device *dev)
{
        struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
        struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_res_holder;

        spin_lock(&dev->dev_reservation_lock);
        pr_res_holder = dev->dev_pr_res_holder;
        if (pr_res_holder != NULL) {
                struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;
                __core_scsi3_complete_pro_release(dev, pr_res_nacl,
                                pr_res_holder, 0);
        }
        spin_unlock(&dev->dev_reservation_lock);

        spin_lock(&pr_tmpl->registration_lock);
        list_for_each_entry_safe(pr_reg, pr_reg_tmp,
                        &pr_tmpl->registration_list, pr_reg_list) {

                __core_scsi3_free_registration(dev, pr_reg, NULL, 0);
        }
        spin_unlock(&pr_tmpl->registration_lock);

        spin_lock(&pr_tmpl->aptpl_reg_lock);
        list_for_each_entry_safe(pr_reg, pr_reg_tmp, &pr_tmpl->aptpl_reg_list,
                                pr_reg_aptpl_list) {
                list_del(&pr_reg->pr_reg_aptpl_list);
                kfree(pr_reg->pr_aptpl_buf);
                kmem_cache_free(t10_pr_reg_cache, pr_reg);
        }
        spin_unlock(&pr_tmpl->aptpl_reg_lock);
}

static int core_scsi3_tpg_depend_item(struct se_portal_group *tpg)
{
        return configfs_depend_item(tpg->se_tpg_tfo->tf_subsys,
                        &tpg->tpg_group.cg_item);
}

static void core_scsi3_tpg_undepend_item(struct se_portal_group *tpg)
{
        configfs_undepend_item(tpg->se_tpg_tfo->tf_subsys,
                        &tpg->tpg_group.cg_item);

        atomic_dec(&tpg->tpg_pr_ref_count);
        smp_mb__after_atomic_dec();
}

static int core_scsi3_nodeacl_depend_item(struct se_node_acl *nacl)
{
        struct se_portal_group *tpg = nacl->se_tpg;

        if (nacl->dynamic_node_acl)
                return 0;

        return configfs_depend_item(tpg->se_tpg_tfo->tf_subsys,
                        &nacl->acl_group.cg_item);
}

static void core_scsi3_nodeacl_undepend_item(struct se_node_acl *nacl)
{
        struct se_portal_group *tpg = nacl->se_tpg;

        if (nacl->dynamic_node_acl) {
                atomic_dec(&nacl->acl_pr_ref_count);
                smp_mb__after_atomic_dec();
                return;
        }

        configfs_undepend_item(tpg->se_tpg_tfo->tf_subsys,
                        &nacl->acl_group.cg_item);

        atomic_dec(&nacl->acl_pr_ref_count);
        smp_mb__after_atomic_dec();
}

static int core_scsi3_lunacl_depend_item(struct se_dev_entry *se_deve)
{
        struct se_lun_acl *lun_acl = se_deve->se_lun_acl;
        struct se_node_acl *nacl;
        struct se_portal_group *tpg;
        /*
         * For nacl->dynamic_node_acl=1
         */
        if (!lun_acl)
                return 0;

        nacl = lun_acl->se_lun_nacl;
        tpg = nacl->se_tpg;

        return configfs_depend_item(tpg->se_tpg_tfo->tf_subsys,
                        &lun_acl->se_lun_group.cg_item);
}

static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *se_deve)
{
        struct se_lun_acl *lun_acl = se_deve->se_lun_acl;
        struct se_node_acl *nacl;
        struct se_portal_group *tpg;
        /*
         * For nacl->dynamic_node_acl=1
         */
        if (!lun_acl) {
                atomic_dec(&se_deve->pr_ref_count);
                smp_mb__after_atomic_dec();
                return;
        }
        nacl = lun_acl->se_lun_nacl;
        tpg = nacl->se_tpg;

        configfs_undepend_item(tpg->se_tpg_tfo->tf_subsys,
                        &lun_acl->se_lun_group.cg_item);

        atomic_dec(&se_deve->pr_ref_count);
        smp_mb__after_atomic_dec();
}

static int core_scsi3_decode_spec_i_port(
        struct se_cmd *cmd,
        struct se_portal_group *tpg,
        unsigned char *l_isid,
        u64 sa_res_key,
        int all_tg_pt,
        int aptpl)
{
        struct se_device *dev = cmd->se_dev;
        struct se_port *tmp_port;
        struct se_portal_group *dest_tpg = NULL, *tmp_tpg;
        struct se_session *se_sess = cmd->se_sess;
        struct se_node_acl *dest_node_acl = NULL;
        struct se_dev_entry *dest_se_deve = NULL, *local_se_deve;
        struct t10_pr_registration *dest_pr_reg, *local_pr_reg, *pr_reg_e;
        struct t10_pr_registration *pr_reg_tmp, *pr_reg_tmp_safe;
        struct list_head tid_dest_list;
        struct pr_transport_id_holder *tidh_new, *tidh, *tidh_tmp;
        struct target_core_fabric_ops *tmp_tf_ops;
        unsigned char *buf;
        unsigned char *ptr, *i_str = NULL, proto_ident, tmp_proto_ident;
        char *iport_ptr = NULL, dest_iport[64], i_buf[PR_REG_ISID_ID_LEN];
        u32 tpdl, tid_len = 0;
        int ret, dest_local_nexus, prf_isid;
        u32 dest_rtpi = 0;

        memset(dest_iport, 0, 64);
        INIT_LIST_HEAD(&tid_dest_list);

        local_se_deve = &se_sess->se_node_acl->device_list[cmd->orig_fe_lun];
        /*
         * Allocate a struct pr_transport_id_holder and setup the
         * local_node_acl and local_se_deve pointers and add to
         * struct list_head tid_dest_list for add registration
         * processing in the loop of tid_dest_list below.
         */
        tidh_new = kzalloc(sizeof(struct pr_transport_id_holder), GFP_KERNEL);
        if (!tidh_new) {
                pr_err("Unable to allocate tidh_new\n");
                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                return -EINVAL;
        }
        INIT_LIST_HEAD(&tidh_new->dest_list);
        tidh_new->dest_tpg = tpg;
        tidh_new->dest_node_acl = se_sess->se_node_acl;
        tidh_new->dest_se_deve = local_se_deve;

        local_pr_reg = __core_scsi3_alloc_registration(cmd->se_dev,
                                se_sess->se_node_acl, local_se_deve, l_isid,
                                sa_res_key, all_tg_pt, aptpl);
        if (!local_pr_reg) {
                kfree(tidh_new);
                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                return -ENOMEM;
        }
        tidh_new->dest_pr_reg = local_pr_reg;
        /*
         * The local I_T nexus does not hold any configfs dependances,
         * so we set tid_h->dest_local_nexus=1 to prevent the
         * configfs_undepend_item() calls in the tid_dest_list loops below.
         */
        tidh_new->dest_local_nexus = 1;
        list_add_tail(&tidh_new->dest_list, &tid_dest_list);

        buf = transport_kmap_data_sg(cmd);
        /*
         * For a PERSISTENT RESERVE OUT specify initiator ports payload,
         * first extract TransportID Parameter Data Length, and make sure
         * the value matches up to the SCSI expected data transfer length.
         */
        tpdl = (buf[24] & 0xff) << 24;
        tpdl |= (buf[25] & 0xff) << 16;
        tpdl |= (buf[26] & 0xff) << 8;
        tpdl |= buf[27] & 0xff;

        if ((tpdl + 28) != cmd->data_length) {
                pr_err("SPC-3 PR: Illegal tpdl: %u + 28 byte header"
                        " does not equal CDB data_length: %u\n", tpdl,
                        cmd->data_length);
                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                ret = -EINVAL;
                goto out;
        }
        /*
         * Start processing the received transport IDs using the
         * receiving I_T Nexus portal's fabric dependent methods to
         * obtain the SCSI Initiator Port/Device Identifiers.
         */
        ptr = &buf[28];

        while (tpdl > 0) {
                proto_ident = (ptr[0] & 0x0f);
                dest_tpg = NULL;

                spin_lock(&dev->se_port_lock);
                list_for_each_entry(tmp_port, &dev->dev_sep_list, sep_list) {
                        tmp_tpg = tmp_port->sep_tpg;
                        if (!tmp_tpg)
                                continue;
                        tmp_tf_ops = tmp_tpg->se_tpg_tfo;
                        if (!tmp_tf_ops)
                                continue;
                        if (!tmp_tf_ops->get_fabric_proto_ident ||
                            !tmp_tf_ops->tpg_parse_pr_out_transport_id)
                                continue;
                        /*
                         * Look for the matching proto_ident provided by
                         * the received TransportID
                         */
                        tmp_proto_ident = tmp_tf_ops->get_fabric_proto_ident(tmp_tpg);
                        if (tmp_proto_ident != proto_ident)
                                continue;
                        dest_rtpi = tmp_port->sep_rtpi;

                        i_str = tmp_tf_ops->tpg_parse_pr_out_transport_id(
                                        tmp_tpg, (const char *)ptr, &tid_len,
                                        &iport_ptr);
                        if (!i_str)
                                continue;

                        atomic_inc(&tmp_tpg->tpg_pr_ref_count);
                        smp_mb__after_atomic_inc();
                        spin_unlock(&dev->se_port_lock);

                        ret = core_scsi3_tpg_depend_item(tmp_tpg);
                        if (ret != 0) {
                                pr_err(" core_scsi3_tpg_depend_item()"
                                        " for tmp_tpg\n");
                                atomic_dec(&tmp_tpg->tpg_pr_ref_count);
                                smp_mb__after_atomic_dec();
                                cmd->scsi_sense_reason =
                                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                                ret = -EINVAL;
                                goto out;
                        }
                        /*
                         * Locate the desination initiator ACL to be registered
                         * from the decoded fabric module specific TransportID
                         * at *i_str.
                         */
                        spin_lock_irq(&tmp_tpg->acl_node_lock);
                        dest_node_acl = __core_tpg_get_initiator_node_acl(
                                                tmp_tpg, i_str);
                        if (dest_node_acl) {
                                atomic_inc(&dest_node_acl->acl_pr_ref_count);
                                smp_mb__after_atomic_inc();
                        }
                        spin_unlock_irq(&tmp_tpg->acl_node_lock);

                        if (!dest_node_acl) {
                                core_scsi3_tpg_undepend_item(tmp_tpg);
                                spin_lock(&dev->se_port_lock);
                                continue;
                        }

                        ret = core_scsi3_nodeacl_depend_item(dest_node_acl);
                        if (ret != 0) {
                                pr_err("configfs_depend_item() failed"
                                        " for dest_node_acl->acl_group\n");
                                atomic_dec(&dest_node_acl->acl_pr_ref_count);
                                smp_mb__after_atomic_dec();
                                core_scsi3_tpg_undepend_item(tmp_tpg);
                                cmd->scsi_sense_reason =
                                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                                ret = -EINVAL;
                                goto out;
                        }

                        dest_tpg = tmp_tpg;
                        pr_debug("SPC-3 PR SPEC_I_PT: Located %s Node:"
                                " %s Port RTPI: %hu\n",
                                dest_tpg->se_tpg_tfo->get_fabric_name(),
                                dest_node_acl->initiatorname, dest_rtpi);

                        spin_lock(&dev->se_port_lock);
                        break;
                }
                spin_unlock(&dev->se_port_lock);

                if (!dest_tpg) {
                        pr_err("SPC-3 PR SPEC_I_PT: Unable to locate"
                                        " dest_tpg\n");
                        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                        ret = -EINVAL;
                        goto out;
                }
#if 0
                pr_debug("SPC-3 PR SPEC_I_PT: Got %s data_length: %u tpdl: %u"
                        " tid_len: %d for %s + %s\n",
                        dest_tpg->se_tpg_tfo->get_fabric_name(), cmd->data_length,
                        tpdl, tid_len, i_str, iport_ptr);
#endif
                if (tid_len > tpdl) {
                        pr_err("SPC-3 PR SPEC_I_PT: Illegal tid_len:"
                                " %u for Transport ID: %s\n", tid_len, ptr);
                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                        ret = -EINVAL;
                        goto out;
                }
                /*
                 * Locate the desintation struct se_dev_entry pointer for matching
                 * RELATIVE TARGET PORT IDENTIFIER on the receiving I_T Nexus
                 * Target Port.
                 */
                dest_se_deve = core_get_se_deve_from_rtpi(dest_node_acl,
                                        dest_rtpi);
                if (!dest_se_deve) {
                        pr_err("Unable to locate %s dest_se_deve"
                                " from destination RTPI: %hu\n",
                                dest_tpg->se_tpg_tfo->get_fabric_name(),
                                dest_rtpi);

                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                        ret = -EINVAL;
                        goto out;
                }

                ret = core_scsi3_lunacl_depend_item(dest_se_deve);
                if (ret < 0) {
                        pr_err("core_scsi3_lunacl_depend_item()"
                                        " failed\n");
                        atomic_dec(&dest_se_deve->pr_ref_count);
                        smp_mb__after_atomic_dec();
                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        cmd->scsi_sense_reason =
                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                        ret = -EINVAL;
                        goto out;
                }
#if 0
                pr_debug("SPC-3 PR SPEC_I_PT: Located %s Node: %s"
                        " dest_se_deve mapped_lun: %u\n",
                        dest_tpg->se_tpg_tfo->get_fabric_name(),
                        dest_node_acl->initiatorname, dest_se_deve->mapped_lun);
#endif
                /*
                 * Skip any TransportIDs that already have a registration for
                 * this target port.
                 */
                pr_reg_e = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
                                        iport_ptr);
                if (pr_reg_e) {
                        core_scsi3_put_pr_reg(pr_reg_e);
                        core_scsi3_lunacl_undepend_item(dest_se_deve);
                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        ptr += tid_len;
                        tpdl -= tid_len;
                        tid_len = 0;
                        continue;
                }
                /*
                 * Allocate a struct pr_transport_id_holder and setup
                 * the dest_node_acl and dest_se_deve pointers for the
                 * loop below.
                 */
                tidh_new = kzalloc(sizeof(struct pr_transport_id_holder),
                                GFP_KERNEL);
                if (!tidh_new) {
                        pr_err("Unable to allocate tidh_new\n");
                        core_scsi3_lunacl_undepend_item(dest_se_deve);
                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        cmd->scsi_sense_reason =
                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
                        ret = -ENOMEM;
                        goto out;
                }
                INIT_LIST_HEAD(&tidh_new->dest_list);
                tidh_new->dest_tpg = dest_tpg;
                tidh_new->dest_node_acl = dest_node_acl;
                tidh_new->dest_se_deve = dest_se_deve;

                /*
                 * Allocate, but do NOT add the registration for the
                 * TransportID referenced SCSI Initiator port.  This
                 * done because of the following from spc4r17 in section
                 * 6.14.3 wrt SPEC_I_PT:
                 *
                 * "If a registration fails for any initiator port (e.g., if th
                 * logical unit does not have enough resources available to
                 * hold the registration information), no registrations shall be
                 * made, and the command shall be terminated with
                 * CHECK CONDITION status."
                 *
                 * That means we call __core_scsi3_alloc_registration() here,
                 * and then call __core_scsi3_add_registration() in the
                 * 2nd loop which will never fail.
                 */
                dest_pr_reg = __core_scsi3_alloc_registration(cmd->se_dev,
                                dest_node_acl, dest_se_deve, iport_ptr,
                                sa_res_key, all_tg_pt, aptpl);
                if (!dest_pr_reg) {
                        core_scsi3_lunacl_undepend_item(dest_se_deve);
                        core_scsi3_nodeacl_undepend_item(dest_node_acl);
                        core_scsi3_tpg_undepend_item(dest_tpg);
                        kfree(tidh_new);
                        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
                        ret = -EINVAL;
                        goto out;
                }
                tidh_new->dest_pr_reg = dest_pr_reg;
                list_add_tail(&tidh_new->dest_list, &tid_dest_list);

                ptr += tid_len;
                tpdl -= tid_len;
                tid_len = 0;

        }

        transport_kunmap_data_sg(cmd);

        /*
         * Go ahead and create a registrations from tid_dest_list for the
         * SPEC_I_PT provided TransportID for the *tidh referenced dest_node_acl
         * and dest_se_deve.
         *
         * The SA Reservation Key from the PROUT is set for the
         * registration, and ALL_TG_PT is also passed.  ALL_TG_PT=1
         * means that the TransportID Initiator port will be
         * registered on all of the target ports in the SCSI target device
         * ALL_TG_PT=0 means the registration will only be for the
         * SCSI target port the PROUT REGISTER with SPEC_I_PT=1
         * was received.
         */
        list_for_each_entry_safe(tidh, tidh_tmp, &tid_dest_list, dest_list) {
                dest_tpg = tidh->dest_tpg;
                dest_node_acl = tidh->dest_node_acl;
                dest_se_deve = tidh->dest_se_deve;
                dest_pr_reg = tidh->dest_pr_reg;
                dest_local_nexus = tidh->dest_local_nexus;

                list_del(&tidh->dest_list);
                kfree(tidh);

                memset(i_buf, 0, PR_REG_ISID_ID_LEN);
                prf_isid = core_pr_dump_initiator_port(dest_pr_reg, &i_buf[0],
                                                PR_REG_ISID_ID_LEN);

                __core_scsi3_add_registration(cmd->se_dev, dest_node_acl,
                                        dest_pr_reg, 0, 0);

                pr_debug("SPC-3 PR [%s] SPEC_I_PT: Successfully"
                        " registered Transport ID for Node: %s%s Mapped LUN:"
                        " %u\n", dest_tpg->se_tpg_tfo->get_fabric_name(),
                        dest_node_acl->initiatorname, (prf_isid) ?
                        &i_buf[0] : "", dest_se_deve->mapped_lun);

                if (dest_local_nexus)
                        continue;

                core_scsi3_lunacl_undepend_item(dest_se_deve);
                core_scsi3_nodeacl_undepend_item(dest_node_acl);
                core_scsi3_tpg_undepend_item(dest_tpg);
        }

        return 0;
out:
        transport_kunmap_data_sg(cmd);
        /*
         * For the failure case, release everything from tid_dest_list
         * including *dest_pr_reg and the configfs dependances..
         */
        list_for_each_entry_safe(tidh, tidh_tmp, &tid_dest_list, dest_list) {
                dest_tpg = tidh->dest_tpg;
                dest_node_acl = tidh->dest_node_acl;
                dest_se_deve = tidh->dest_se_deve;
                dest_pr_reg = tidh->dest_pr_reg;
                dest_local_nexus = tidh->dest_local_nexus;

                list_del(&tidh->dest_list);
                kfree(tidh);
                /*
                 * Release any extra ALL_TG_PT=1 registrations for
                 * the SPEC_I_PT=1 case.
                 */
                list_for_each_entry_safe(pr_reg_tmp, pr_reg_tmp_safe,
                                &dest_pr_reg->pr_reg_atp_list,
                                pr_reg_atp_mem_list) {
                        list_del(&pr_reg_tmp->pr_reg_atp_mem_list);
                        core_scsi3_lunacl_undepend_item(pr_reg_tmp->pr_reg_deve);
                        kmem_cache_free(t10_pr_reg_cache, pr_reg_tmp);
                }

                kfree(dest_pr_reg->pr_aptpl_buf);
                kmem_cache_free(t10_pr_reg_cache, dest_pr_reg);

                if (dest_local_nexus)
                        continue;

                core_scsi3_lunacl_undepend_item(dest_se_deve);
                core_scsi3_nodeacl_undepend_item(dest_node_acl);
                core_scsi3_tpg_undepend_item(dest_tpg);
        }
        return ret;
}

/*
 * Called with struct se_device->dev_reservation_lock held
 */
static int __core_scsi3_update_aptpl_buf(
        struct se_device *dev,
        unsigned char *buf,
        u32 pr_aptpl_buf_len,
        int clear_aptpl_metadata)
{
        struct se_lun *lun;
        struct se_portal_group *tpg;
        struct se_subsystem_dev *su_dev = dev->se_sub_dev;
        struct t10_pr_registration *pr_reg;
        unsigned char tmp[512], isid_buf[32];
        ssize_t len = 0;
        int reg_count = 0;

        memset(buf, 0, pr_aptpl_buf_len);
        /*
         * Called to clear metadata once APTPL has been deactivated.
         */
        if (clear_aptpl_metadata) {
                snprintf(buf, pr_aptpl_buf_len,
                                "No Registrations or Reservations\n");
                return 0;
        }
        /*
         * Walk the registration list..
         */
        spin_lock(&su_dev->t10_pr.registration_lock);
        list_for_each_entry(pr_reg, &su_dev->t10_pr.registration_list,
                        pr_reg_list) {

                tmp[0] = '\0';
                isid_buf[0] = '\0';
                tpg = pr_reg->pr_reg_nacl->se_tpg;
                lun = pr_reg->pr_reg_tg_pt_lun;
                /*
                 * Write out any ISID value to APTPL metadata that was included
                 * in the original registration.
                 */
                if (pr_reg->isid_present_at_reg)
                        snprintf(isid_buf, 32, "initiator_sid=%s\n",
                                        pr_reg->pr_reg_isid);
                /*
                 * Include special metadata if the pr_reg matches the
                 * reservation holder.
                 */
                if (dev->dev_pr_res_holder == pr_reg) {
                        snprintf(tmp, 512, "PR_REG_START: %d"
                                "\ninitiator_fabric=%s\n"
                                "initiator_node=%s\n%s"
                                "sa_res_key=%llu\n"
                                "res_holder=1\nres_type=%02x\n"
                                "res_scope=%02x\nres_all_tg_pt=%d\n"
                                "mapped_lun=%u\n", reg_count,
                                tpg->se_tpg_tfo->get_fabric_name(),
                                pr_reg->pr_reg_nacl->initiatorname, isid_buf,
                                pr_reg->pr_res_key, pr_reg->pr_res_type,
                                pr_reg->pr_res_scope, pr_reg->pr_reg_all_tg_pt,
                                pr_reg->pr_res_mapped_lun);
                } else {
                        snprintf(tmp, 512, "PR_REG_START: %d\n"
                                "initiator_fabric=%s\ninitiator_node=%s\n%s"
                                "sa_res_key=%llu\nres_holder=0\n"
                                "res_all_tg_pt=%d\nmapped_lun=%u\n",
                                reg_count, tpg->se_tpg_tfo->get_fabric_name(),
                                pr_reg->pr_reg_nacl->initiatorname, isid_buf,
                                pr_reg->pr_res_key, pr_reg->pr_reg_all_tg_pt,
                                pr_reg->pr_res_mapped_lun);
                }

                if ((len + strlen(tmp) >= pr_aptpl_buf_len)) {
                        pr_err("Unable to update renaming"
                                " APTPL metadata\n");
                        spin_unlock(&su_dev->t10_pr.registration_lock);
                        return -EMSGSIZE;
                }
                len += sprintf(buf+len, "%s", tmp);

                /*
                 * Include information about the associated SCSI target port.
                 */
                snprintf(tmp, 512, "target_fabric=%s\ntarget_node=%s\n"
                        "tpgt=%hu\nport_rtpi=%hu\ntarget_lun=%u\nPR_REG_END:"
                        " %d\n", tpg->se_tpg_tfo->get_fabric_name(),
                        tpg->se_tpg_tfo->tpg_get_wwn(tpg),
                        tpg->se_tpg_tfo->tpg_get_tag(tpg),
                        lun->lun_sep->sep_rtpi, lun->unpacked_lun, reg_count);

                if ((len + strlen(tmp) >= pr_aptpl_buf_len)) {
                        pr_err("Unable to update renaming"
                                " APTPL metadata\n");
                        spin_unlock(&su_dev->t10_pr.registration_lock);
                        return -EMSGSIZE;
                }
                len += sprintf(buf+len, "%s", tmp);
                reg_count++;
        }
        spin_unlock(&su_dev->t10_pr.registration_lock);

        if (!reg_count)
                len += sprintf(buf+len, "No Registrations or Reservations");

        return 0;
}

static int core_scsi3_update_aptpl_buf(
        struct se_device *dev,
        unsigned char *buf,
        u32 pr_aptpl_buf_len,
        int clear_aptpl_metadata)
{
        int ret;