Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / target / target_core_pr.c
diff --git a/kernel/drivers/target/target_core_pr.c b/kernel/drivers/target/target_core_pr.c
new file mode 100644 (file)
index 0000000..a15411c
--- /dev/null
@@ -0,0 +1,4107 @@
+/*******************************************************************************
+ * Filename:  target_core_pr.c
+ *
+ * This file contains SPC-3 compliant persistent reservations and
+ * legacy SPC-2 reservations with compatible reservation handling (CRH=1)
+ *
+ * (c) Copyright 2009-2013 Datera, Inc.
+ *
+ * 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 <linux/file.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;
+};
+
+void core_pr_dump_initiator_port(
+       struct t10_pr_registration *pr_reg,
+       char *buf,
+       u32 size)
+{
+       if (!pr_reg->isid_present_at_reg)
+               buf[0] = '\0';
+
+       snprintf(buf, size, ",i,0x%s", pr_reg->pr_reg_isid);
+}
+
+enum register_type {
+       REGISTER,
+       REGISTER_AND_IGNORE_EXISTING_KEY,
+       REGISTER_AND_MOVE,
+};
+
+enum preempt_type {
+       PREEMPT,
+       PREEMPT_AND_ABORT,
+};
+
+static void __core_scsi3_complete_pro_release(struct se_device *, struct se_node_acl *,
+                                             struct t10_pr_registration *, int, int);
+
+static int is_reservation_holder(
+       struct t10_pr_registration *pr_res_holder,
+       struct t10_pr_registration *pr_reg)
+{
+       int pr_res_type;
+
+       if (pr_res_holder) {
+               pr_res_type = pr_res_holder->pr_res_type;
+
+               return pr_res_holder == pr_reg ||
+                      pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG ||
+                      pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG;
+       }
+       return 0;
+}
+
+static sense_reason_t
+target_scsi2_reservation_check(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *sess = cmd->se_sess;
+
+       switch (cmd->t_task_cdb[0]) {
+       case INQUIRY:
+       case RELEASE:
+       case RELEASE_10:
+               return 0;
+       default:
+               break;
+       }
+
+       if (!dev->dev_reserved_node_acl || !sess)
+               return 0;
+
+       if (dev->dev_reserved_node_acl != sess->se_node_acl)
+               return TCM_RESERVATION_CONFLICT;
+
+       if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS_WITH_ISID) {
+               if (dev->dev_res_bin_isid != sess->sess_bin_isid)
+                       return TCM_RESERVATION_CONFLICT;
+       }
+
+       return 0;
+}
+
+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_device *dev = cmd->se_dev;
+       struct t10_pr_registration *pr_reg;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       int conflict = 0;
+
+       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");
+               return -EBUSY;
+       }
+
+       return 0;
+}
+
+sense_reason_t
+target_scsi2_reservation_release(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *sess = cmd->se_sess;
+       struct se_portal_group *tpg;
+       int rc;
+
+       if (!sess || !sess->se_tpg)
+               goto out;
+       rc = target_check_scsi2_reservation_conflict(cmd);
+       if (rc == 1)
+               goto out;
+       if (rc < 0)
+               return TCM_RESERVATION_CONFLICT;
+
+       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;
+
+       if (dev->dev_res_bin_isid != sess->sess_bin_isid)
+               goto out_unlock;
+
+       dev->dev_reserved_node_acl = NULL;
+       dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
+       if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS_WITH_ISID) {
+               dev->dev_res_bin_isid = 0;
+               dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS_WITH_ISID;
+       }
+       tpg = sess->se_tpg;
+       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:
+       target_complete_cmd(cmd, GOOD);
+       return 0;
+}
+
+sense_reason_t
+target_scsi2_reservation_reserve(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *sess = cmd->se_sess;
+       struct se_portal_group *tpg;
+       sense_reason_t ret = 0;
+       int 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");
+               return TCM_UNSUPPORTED_SCSI_OPCODE;
+       }
+       /*
+        * This is currently the case for target_core_mod passthrough struct se_cmd
+        * ops
+        */
+       if (!sess || !sess->se_tpg)
+               goto out;
+       rc = target_check_scsi2_reservation_conflict(cmd);
+       if (rc == 1)
+               goto out;
+
+       if (rc < 0)
+               return TCM_RESERVATION_CONFLICT;
+
+       tpg = sess->se_tpg;
+       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);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out_unlock;
+       }
+
+       dev->dev_reserved_node_acl = sess->se_node_acl;
+       dev->dev_reservation_flags |= DRF_SPC2_RESERVATIONS;
+       if (sess->sess_bin_isid != 0) {
+               dev->dev_res_bin_isid = sess->sess_bin_isid;
+               dev->dev_reservation_flags |= DRF_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)
+               target_complete_cmd(cmd, GOOD);
+       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,
+       u32 pr_reg_type)
+{
+       unsigned char *cdb = cmd->t_task_cdb;
+       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 */
+
+       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 target_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 SERVICE_ACTION_IN_12:
+       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) {
+               pr_debug("Allowing explicit CDB: 0x%02x for %s"
+                       " reservation holder\n", cdb[0],
+                       core_scsi3_pr_dump_type(pr_reg_type));
+
+               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 (!registered_nexus) {
+                               pr_debug("Allowing implicit CDB: 0x%02x"
+                                       " for %s reservation on unregistered"
+                                       " nexus\n", cdb[0],
+                                       core_scsi3_pr_dump_type(pr_reg_type));
+                       }
+
+                       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.
+                        */
+
+                       pr_debug("Allowing implicit CDB: 0x%02x for %s"
+                               " reservation\n", cdb[0],
+                               core_scsi3_pr_dump_type(pr_reg_type));
+
+                       return 0;
+               }
+       } else if (we && registered_nexus) {
+               /*
+                * Reads are allowed for Write Exclusive locks
+                * from all registrants.
+                */
+               if (cmd->data_direction == DMA_FROM_DEVICE) {
+                       pr_debug("Allowing READ CDB: 0x%02x for %s"
+                               " reservation\n", cdb[0],
+                               core_scsi3_pr_dump_type(pr_reg_type));
+
+                       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 sense_reason_t
+target_scsi3_pr_reservation_check(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *sess = cmd->se_sess;
+       u32 pr_reg_type;
+
+       if (!dev->dev_pr_res_holder)
+               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)
+               goto check_nonholder;
+
+       if (dev->dev_pr_res_holder->isid_present_at_reg) {
+               if (dev->dev_pr_res_holder->pr_reg_bin_isid !=
+                   sess->sess_bin_isid) {
+                       pr_reg_type |= 0x80000000;
+                       goto check_nonholder;
+               }
+       }
+
+       return 0;
+
+check_nonholder:
+       if (core_scsi3_pr_seq_non_holder(cmd, pr_reg_type))
+               return TCM_RESERVATION_CONFLICT;
+       return 0;
+}
+
+static u32 core_scsi3_pr_generation(struct se_device *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 = dev->t10_pr.pr_generation++;
+       spin_unlock(&dev->dev_reservation_lock);
+
+       return prg;
+}
+
+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 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;
+       }
+
+       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;
+       const 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_mb(&port->sep_tg_pt_ref_cnt);
+               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 explicit 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_mb(&deve_tmp->pr_ref_count);
+                       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_mb(&port->sep_tg_pt_ref_cnt);
+                               atomic_dec_mb(&deve_tmp->pr_ref_count);
+                               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_mb(&port->sep_tg_pt_ref_cnt);
+                               atomic_dec_mb(&deve_tmp->pr_ref_count);
+                               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_mb(&port->sep_tg_pt_ref_cnt);
+       }
+       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;
+       }
+
+       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];
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+       core_pr_dump_initiator_port(pr_reg, i_buf, 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,
+               i_buf);
+}
+
+static void __core_scsi3_add_registration(struct se_device *, struct se_node_acl *,
+                               struct t10_pr_registration *, enum register_type, 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->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_node_acl *nacl,
+       u32 mapped_lun)
+{
+       struct se_dev_entry *deve = nacl->device_list[mapped_lun];
+
+       if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
+               return 0;
+
+       return __core_scsi3_check_aptpl_registration(dev, tpg, lun,
+                               lun->unpacked_lun, nacl, deve);
+}
+
+static void __core_scsi3_dump_registration(
+       const struct target_core_fabric_ops *tfo,
+       struct se_device *dev,
+       struct se_node_acl *nacl,
+       struct t10_pr_registration *pr_reg,
+       enum register_type register_type)
+{
+       struct se_portal_group *se_tpg = nacl->se_tpg;
+       char i_buf[PR_REG_ISID_ID_LEN];
+
+       memset(&i_buf[0], 0, PR_REG_ISID_ID_LEN);
+       core_pr_dump_initiator_port(pr_reg, i_buf, 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 == REGISTER_AND_MOVE) ?
+               "_AND_MOVE" : (register_type == REGISTER_AND_IGNORE_EXISTING_KEY) ?
+               "_AND_IGNORE_EXISTING_KEY" : "", nacl->initiatorname,
+               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,
+       enum register_type register_type,
+       int register_move)
+{
+       const 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->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) ?
+                       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,
+       enum register_type 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->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->dev_attrib.enforce_pr_isids)
+                                       continue;
+                       }
+                       atomic_inc_mb(&pr_reg->pr_res_holders);
+                       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_mb(&pr_reg->pr_res_holders);
+               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_mb(&pr_reg->pr_res_holders);
+}
+
+static int core_scsi3_check_implicit_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 implicit 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, 1);
+               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 implicitly 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)
+       __releases(&pr_tmpl->registration_lock)
+       __acquires(&pr_tmpl->registration_lock)
+{
+       const struct target_core_fabric_ops *tfo =
+                       pr_reg->pr_reg_nacl->se_tpg->se_tpg_tfo;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       char i_buf[PR_REG_ISID_ID_LEN];
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+       core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);
+
+       pr_reg->pr_reg_deve->def_pr_registered = 0;
+       pr_reg->pr_reg_deve->pr_res_key = 0;
+       if (!list_empty(&pr_reg->pr_reg_list))
+               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,
+               i_buf);
+       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;
+               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->t10_pr;
+       struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_res_holder;
+       bool free_reg = false;
+       /*
+        * 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, 1);
+               free_reg = true;
+       }
+       spin_unlock(&dev->dev_reservation_lock);
+       /*
+        * Release any registration associated with the struct se_node_acl.
+        */
+       spin_lock(&pr_tmpl->registration_lock);
+       if (pr_res_holder && free_reg)
+               __core_scsi3_free_registration(dev, pr_res_holder, NULL, 0);
+
+       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->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, 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);
+               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 target_depend_item(&tpg->tpg_group.cg_item);
+}
+
+static void core_scsi3_tpg_undepend_item(struct se_portal_group *tpg)
+{
+       target_undepend_item(&tpg->tpg_group.cg_item);
+       atomic_dec_mb(&tpg->tpg_pr_ref_count);
+}
+
+static int core_scsi3_nodeacl_depend_item(struct se_node_acl *nacl)
+{
+       if (nacl->dynamic_node_acl)
+               return 0;
+       return target_depend_item(&nacl->acl_group.cg_item);
+}
+
+static void core_scsi3_nodeacl_undepend_item(struct se_node_acl *nacl)
+{
+       if (!nacl->dynamic_node_acl)
+               target_undepend_item(&nacl->acl_group.cg_item);
+       atomic_dec_mb(&nacl->acl_pr_ref_count);
+}
+
+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 target_depend_item(&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_mb(&se_deve->pr_ref_count);
+               return;
+       }
+       nacl = lun_acl->se_lun_nacl;
+       tpg = nacl->se_tpg;
+
+       target_undepend_item(&lun_acl->se_lun_group.cg_item);
+       atomic_dec_mb(&se_deve->pr_ref_count);
+}
+
+static sense_reason_t
+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;
+       LIST_HEAD(tid_dest_list);
+       struct pr_transport_id_holder *tidh_new, *tidh, *tidh_tmp;
+       const 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, i_buf[PR_REG_ISID_ID_LEN];
+       sense_reason_t ret;
+       u32 tpdl, tid_len = 0;
+       int dest_local_nexus;
+       u32 dest_rtpi = 0;
+
+       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");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       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);
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       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);
+
+       if (cmd->data_length < 28) {
+               pr_warn("SPC-PR: Received PR OUT parameter list"
+                       " length too small: %u\n", cmd->data_length);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf) {
+               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               goto out;
+       }
+
+       /*
+        * 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);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out_unmap;
+       }
+       /*
+        * 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_mb(&tmp_tpg->tpg_pr_ref_count);
+                       spin_unlock(&dev->se_port_lock);
+
+                       if (core_scsi3_tpg_depend_item(tmp_tpg)) {
+                               pr_err(" core_scsi3_tpg_depend_item()"
+                                       " for tmp_tpg\n");
+                               atomic_dec_mb(&tmp_tpg->tpg_pr_ref_count);
+                               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                               goto out_unmap;
+                       }
+                       /*
+                        * Locate the destination 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_mb(&dest_node_acl->acl_pr_ref_count);
+                       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;
+                       }
+
+                       if (core_scsi3_nodeacl_depend_item(dest_node_acl)) {
+                               pr_err("configfs_depend_item() failed"
+                                       " for dest_node_acl->acl_group\n");
+                               atomic_dec_mb(&dest_node_acl->acl_pr_ref_count);
+                               core_scsi3_tpg_undepend_item(tmp_tpg);
+                               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                               goto out_unmap;
+                       }
+
+                       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");
+                       ret = TCM_INVALID_PARAMETER_LIST;
+                       goto out_unmap;
+               }
+
+               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);
+
+               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);
+                       ret = TCM_INVALID_PARAMETER_LIST;
+                       goto out_unmap;
+               }
+               /*
+                * 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);
+                       ret = TCM_INVALID_PARAMETER_LIST;
+                       goto out_unmap;
+               }
+
+               if (core_scsi3_lunacl_depend_item(dest_se_deve)) {
+                       pr_err("core_scsi3_lunacl_depend_item()"
+                                       " failed\n");
+                       atomic_dec_mb(&dest_se_deve->pr_ref_count);
+                       core_scsi3_nodeacl_undepend_item(dest_node_acl);
+                       core_scsi3_tpg_undepend_item(dest_tpg);
+                       ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                       goto out_unmap;
+               }
+
+               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);
+
+               /*
+                * 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);
+                       ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                       goto out_unmap;
+               }
+               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);
+                       ret = TCM_INVALID_PARAMETER_LIST;
+                       goto out_unmap;
+               }
+               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);
+               core_pr_dump_initiator_port(dest_pr_reg, i_buf, 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, i_buf, 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_unmap:
+       transport_kunmap_data_sg(cmd);
+out:
+       /*
+        * 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);
+               }
+
+               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;
+}
+
+static int core_scsi3_update_aptpl_buf(
+       struct se_device *dev,
+       unsigned char *buf,
+       u32 pr_aptpl_buf_len)
+{
+       struct se_lun *lun;
+       struct se_portal_group *tpg;
+       struct t10_pr_registration *pr_reg;
+       unsigned char tmp[512], isid_buf[32];
+       ssize_t len = 0;
+       int reg_count = 0;
+       int ret = 0;
+
+       spin_lock(&dev->dev_reservation_lock);
+       spin_lock(&dev->t10_pr.registration_lock);
+       /*
+        * Walk the registration list..
+        */
+       list_for_each_entry(pr_reg, &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,"
+                              " reallocating larger buffer\n");
+                       ret = -EMSGSIZE;
+                       goto out;
+               }
+               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,"
+                              " reallocating larger buffer\n");
+                       ret = -EMSGSIZE;
+                       goto out;
+               }
+               len += sprintf(buf+len, "%s", tmp);
+               reg_count++;
+       }
+
+       if (!reg_count)
+               len += sprintf(buf+len, "No Registrations or Reservations");
+
+out:
+       spin_unlock(&dev->t10_pr.registration_lock);
+       spin_unlock(&dev->dev_reservation_lock);
+
+       return ret;
+}
+
+static int __core_scsi3_write_aptpl_to_file(
+       struct se_device *dev,
+       unsigned char *buf)
+{
+       struct t10_wwn *wwn = &dev->t10_wwn;
+       struct file *file;
+       int flags = O_RDWR | O_CREAT | O_TRUNC;
+       char path[512];
+       u32 pr_aptpl_buf_len;
+       int ret;
+
+       memset(path, 0, 512);
+
+       if (strlen(&wwn->unit_serial[0]) >= 512) {
+               pr_err("WWN value for struct se_device does not fit"
+                       " into path buffer\n");
+               return -EMSGSIZE;
+       }
+
+       snprintf(path, 512, "/var/target/pr/aptpl_%s", &wwn->unit_serial[0]);
+       file = filp_open(path, flags, 0600);
+       if (IS_ERR(file)) {
+               pr_err("filp_open(%s) for APTPL metadata"
+                       " failed\n", path);
+               return PTR_ERR(file);
+       }
+
+       pr_aptpl_buf_len = (strlen(buf) + 1); /* Add extra for NULL */
+
+       ret = kernel_write(file, buf, pr_aptpl_buf_len, 0);
+
+       if (ret < 0)
+               pr_debug("Error writing APTPL metadata file: %s\n", path);
+       fput(file);
+
+       return (ret < 0) ? -EIO : 0;
+}
+
+/*
+ * Clear the APTPL metadata if APTPL has been disabled, otherwise
+ * write out the updated metadata to struct file for this SCSI device.
+ */
+static sense_reason_t core_scsi3_update_and_write_aptpl(struct se_device *dev, bool aptpl)
+{
+       unsigned char *buf;
+       int rc, len = PR_APTPL_BUF_LEN;
+
+       if (!aptpl) {
+               char *null_buf = "No Registrations or Reservations\n";
+
+               rc = __core_scsi3_write_aptpl_to_file(dev, null_buf);
+               dev->t10_pr.pr_aptpl_active = 0;
+               pr_debug("SPC-3 PR: Set APTPL Bit Deactivated\n");
+
+               if (rc)
+                       return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+               return 0;
+       }
+retry:
+       buf = vzalloc(len);
+       if (!buf)
+               return TCM_OUT_OF_RESOURCES;
+
+       rc = core_scsi3_update_aptpl_buf(dev, buf, len);
+       if (rc < 0) {
+               vfree(buf);
+               len *= 2;
+               goto retry;
+       }
+
+       rc = __core_scsi3_write_aptpl_to_file(dev, buf);
+       if (rc != 0) {
+               pr_err("SPC-3 PR: Could not update APTPL\n");
+               vfree(buf);
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       dev->t10_pr.pr_aptpl_active = 1;
+       vfree(buf);
+       pr_debug("SPC-3 PR: Set APTPL Bit Activated\n");
+       return 0;
+}
+
+static sense_reason_t
+core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
+               bool aptpl, bool all_tg_pt, bool spec_i_pt, enum register_type register_type)
+{
+       struct se_session *se_sess = cmd->se_sess;
+       struct se_device *dev = cmd->se_dev;
+       struct se_dev_entry *se_deve;
+       struct se_lun *se_lun = cmd->se_lun;
+       struct se_portal_group *se_tpg;
+       struct t10_pr_registration *pr_reg, *pr_reg_p, *pr_reg_tmp;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       unsigned char isid_buf[PR_REG_ISID_LEN], *isid_ptr = NULL;
+       sense_reason_t ret = TCM_NO_SENSE;
+       int pr_holder = 0, type;
+
+       if (!se_sess || !se_lun) {
+               pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       se_tpg = se_sess->se_tpg;
+       se_deve = se_sess->se_node_acl->device_list[cmd->orig_fe_lun];
+
+       if (se_tpg->se_tpg_tfo->sess_get_initiator_sid) {
+               memset(&isid_buf[0], 0, PR_REG_ISID_LEN);
+               se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess, &isid_buf[0],
+                               PR_REG_ISID_LEN);
+               isid_ptr = &isid_buf[0];
+       }
+       /*
+        * Follow logic from spc4r17 Section 5.7.7, Register Behaviors Table 47
+        */
+       pr_reg = core_scsi3_locate_pr_reg(dev, se_sess->se_node_acl, se_sess);
+       if (!pr_reg) {
+               if (res_key) {
+                       pr_warn("SPC-3 PR: Reservation Key non-zero"
+                               " for SA REGISTER, returning CONFLICT\n");
+                       return TCM_RESERVATION_CONFLICT;
+               }
+               /*
+                * Do nothing but return GOOD status.
+                */
+               if (!sa_res_key)
+                       return 0;
+
+               if (!spec_i_pt) {
+                       /*
+                        * Perform the Service Action REGISTER on the Initiator
+                        * Port Endpoint that the PRO was received from on the
+                        * Logical Unit of the SCSI device server.
+                        */
+                       if (core_scsi3_alloc_registration(cmd->se_dev,
+                                       se_sess->se_node_acl, se_deve, isid_ptr,
+                                       sa_res_key, all_tg_pt, aptpl,
+                                       register_type, 0)) {
+                               pr_err("Unable to allocate"
+                                       " struct t10_pr_registration\n");
+                               return TCM_INVALID_PARAMETER_LIST;
+                       }
+               } else {
+                       /*
+                        * Register both the Initiator port that received
+                        * PROUT SA REGISTER + SPEC_I_PT=1 and extract SCSI
+                        * TransportID from Parameter list and loop through
+                        * fabric dependent parameter list while calling
+                        * logic from of core_scsi3_alloc_registration() for
+                        * each TransportID provided SCSI Initiator Port/Device
+                        */
+                       ret = core_scsi3_decode_spec_i_port(cmd, se_tpg,
+                                       isid_ptr, sa_res_key, all_tg_pt, aptpl);
+                       if (ret != 0)
+                               return ret;
+               }
+
+               return core_scsi3_update_and_write_aptpl(dev, aptpl);
+       }
+
+       /* ok, existing registration */
+
+       if ((register_type == REGISTER) && (res_key != pr_reg->pr_res_key)) {
+               pr_err("SPC-3 PR REGISTER: Received"
+                      " res_key: 0x%016Lx does not match"
+                      " existing SA REGISTER res_key:"
+                      " 0x%016Lx\n", res_key,
+                      pr_reg->pr_res_key);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out;
+       }
+
+       if (spec_i_pt) {
+               pr_err("SPC-3 PR REGISTER: SPEC_I_PT"
+                       " set on a registered nexus\n");
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       /*
+        * An existing ALL_TG_PT=1 registration being released
+        * must also set ALL_TG_PT=1 in the incoming PROUT.
+        */
+       if (pr_reg->pr_reg_all_tg_pt && !all_tg_pt) {
+               pr_err("SPC-3 PR REGISTER: ALL_TG_PT=1"
+                       " registration exists, but ALL_TG_PT=1 bit not"
+                       " present in received PROUT\n");
+               ret = TCM_INVALID_CDB_FIELD;
+               goto out;
+       }
+
+       /*
+        * sa_res_key=1 Change Reservation Key for registered I_T Nexus.
+        */
+       if (sa_res_key) {
+               /*
+                * Increment PRgeneration counter for struct se_device"
+                * upon a successful REGISTER, see spc4r17 section 6.3.2
+                * READ_KEYS service action.
+                */
+               pr_reg->pr_res_generation = core_scsi3_pr_generation(cmd->se_dev);
+               pr_reg->pr_res_key = sa_res_key;
+               pr_debug("SPC-3 PR [%s] REGISTER%s: Changed Reservation"
+                        " Key for %s to: 0x%016Lx PRgeneration:"
+                        " 0x%08x\n", cmd->se_tfo->get_fabric_name(),
+                        (register_type == REGISTER_AND_IGNORE_EXISTING_KEY) ? "_AND_IGNORE_EXISTING_KEY" : "",
+                        pr_reg->pr_reg_nacl->initiatorname,
+                        pr_reg->pr_res_key, pr_reg->pr_res_generation);
+
+       } else {
+               /*
+                * sa_res_key=0 Unregister Reservation Key for registered I_T Nexus.
+                */
+               type = pr_reg->pr_res_type;
+               pr_holder = core_scsi3_check_implicit_release(cmd->se_dev,
+                                                             pr_reg);
+               if (pr_holder < 0) {
+                       ret = TCM_RESERVATION_CONFLICT;
+                       goto out;
+               }
+
+               spin_lock(&pr_tmpl->registration_lock);
+               /*
+                * Release all ALL_TG_PT=1 for the matching SCSI Initiator Port
+                * and matching pr_res_key.
+                */
+               if (pr_reg->pr_reg_all_tg_pt) {
+                       list_for_each_entry_safe(pr_reg_p, pr_reg_tmp,
+                                       &pr_tmpl->registration_list,
+                                       pr_reg_list) {
+
+                               if (!pr_reg_p->pr_reg_all_tg_pt)
+                                       continue;
+                               if (pr_reg_p->pr_res_key != res_key)
+                                       continue;
+                               if (pr_reg == pr_reg_p)
+                                       continue;
+                               if (strcmp(pr_reg->pr_reg_nacl->initiatorname,
+                                          pr_reg_p->pr_reg_nacl->initiatorname))
+                                       continue;
+
+                               __core_scsi3_free_registration(dev,
+                                               pr_reg_p, NULL, 0);
+                       }
+               }
+
+               /*
+                * Release the calling I_T Nexus registration now..
+                */
+               __core_scsi3_free_registration(cmd->se_dev, pr_reg, NULL, 1);
+               pr_reg = NULL;
+
+               /*
+                * From spc4r17, section 5.7.11.3 Unregistering
+                *
+                * If the persistent reservation is a registrants only
+                * type, the device server shall establish a unit
+                * attention condition for the initiator port associated
+                * with every registered I_T nexus except for the I_T
+                * nexus on which the PERSISTENT RESERVE OUT command was
+                * received, with the additional sense code set to
+                * RESERVATIONS RELEASED.
+                */
+               if (pr_holder &&
+                   (type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY ||
+                    type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY)) {
+                       list_for_each_entry(pr_reg_p,
+                                       &pr_tmpl->registration_list,
+                                       pr_reg_list) {
+
+                               core_scsi3_ua_allocate(
+                                       pr_reg_p->pr_reg_nacl,
+                                       pr_reg_p->pr_res_mapped_lun,
+                                       0x2A,
+                                       ASCQ_2AH_RESERVATIONS_RELEASED);
+                       }
+               }
+
+               spin_unlock(&pr_tmpl->registration_lock);
+       }
+
+       ret = core_scsi3_update_and_write_aptpl(dev, aptpl);
+
+out:
+       if (pr_reg)
+               core_scsi3_put_pr_reg(pr_reg);
+       return ret;
+}
+
+unsigned char *core_scsi3_pr_dump_type(int type)
+{
+       switch (type) {
+       case PR_TYPE_WRITE_EXCLUSIVE:
+               return "Write Exclusive Access";
+       case PR_TYPE_EXCLUSIVE_ACCESS:
+               return "Exclusive Access";
+       case PR_TYPE_WRITE_EXCLUSIVE_REGONLY:
+               return "Write Exclusive Access, Registrants Only";
+       case PR_TYPE_EXCLUSIVE_ACCESS_REGONLY:
+               return "Exclusive Access, Registrants Only";
+       case PR_TYPE_WRITE_EXCLUSIVE_ALLREG:
+               return "Write Exclusive Access, All Registrants";
+       case PR_TYPE_EXCLUSIVE_ACCESS_ALLREG:
+               return "Exclusive Access, All Registrants";
+       default:
+               break;
+       }
+
+       return "Unknown SPC-3 PR Type";
+}
+
+static sense_reason_t
+core_scsi3_pro_reserve(struct se_cmd *cmd, int type, int scope, u64 res_key)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *se_sess = cmd->se_sess;
+       struct se_lun *se_lun = cmd->se_lun;
+       struct t10_pr_registration *pr_reg, *pr_res_holder;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       char i_buf[PR_REG_ISID_ID_LEN];
+       sense_reason_t ret;
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+
+       if (!se_sess || !se_lun) {
+               pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * Locate the existing *pr_reg via struct se_node_acl pointers
+        */
+       pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev, se_sess->se_node_acl,
+                               se_sess);
+       if (!pr_reg) {
+               pr_err("SPC-3 PR: Unable to locate"
+                       " PR_REGISTERED *pr_reg for RESERVE\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * From spc4r17 Section 5.7.9: Reserving:
+        *
+        * An application client creates a persistent reservation by issuing
+        * a PERSISTENT RESERVE OUT command with RESERVE service action through
+        * a registered I_T nexus with the following parameters:
+        *    a) RESERVATION KEY set to the value of the reservation key that is
+        *       registered with the logical unit for the I_T nexus; and
+        */
+       if (res_key != pr_reg->pr_res_key) {
+               pr_err("SPC-3 PR RESERVE: Received res_key: 0x%016Lx"
+                       " does not match existing SA REGISTER res_key:"
+                       " 0x%016Lx\n", res_key, pr_reg->pr_res_key);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out_put_pr_reg;
+       }
+       /*
+        * From spc4r17 Section 5.7.9: Reserving:
+        *
+        * From above:
+        *  b) TYPE field and SCOPE field set to the persistent reservation
+        *     being created.
+        *
+        * Only one persistent reservation is allowed at a time per logical unit
+        * and that persistent reservation has a scope of LU_SCOPE.
+        */
+       if (scope != PR_SCOPE_LU_SCOPE) {
+               pr_err("SPC-3 PR: Illegal SCOPE: 0x%02x\n", scope);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out_put_pr_reg;
+       }
+       /*
+        * See if we have an existing PR reservation holder pointer at
+        * struct se_device->dev_pr_res_holder in the form struct t10_pr_registration
+        * *pr_res_holder.
+        */
+       spin_lock(&dev->dev_reservation_lock);
+       pr_res_holder = dev->dev_pr_res_holder;
+       if (pr_res_holder) {
+               /*
+                * From spc4r17 Section 5.7.9: Reserving:
+                *
+                * If the device server receives a PERSISTENT RESERVE OUT
+                * command from an I_T nexus other than a persistent reservation
+                * holder (see 5.7.10) that attempts to create a persistent
+                * reservation when a persistent reservation already exists for
+                * the logical unit, then the command shall be completed with
+                * RESERVATION CONFLICT status.
+                */
+               if (!is_reservation_holder(pr_res_holder, pr_reg)) {
+                       struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;
+                       pr_err("SPC-3 PR: Attempted RESERVE from"
+                               " [%s]: %s while reservation already held by"
+                               " [%s]: %s, returning RESERVATION_CONFLICT\n",
+                               cmd->se_tfo->get_fabric_name(),
+                               se_sess->se_node_acl->initiatorname,
+                               pr_res_nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
+                               pr_res_holder->pr_reg_nacl->initiatorname);
+
+                       spin_unlock(&dev->dev_reservation_lock);
+                       ret = TCM_RESERVATION_CONFLICT;
+                       goto out_put_pr_reg;
+               }
+               /*
+                * From spc4r17 Section 5.7.9: Reserving:
+                *
+                * If a persistent reservation holder attempts to modify the
+                * type or scope of an existing persistent reservation, the
+                * command shall be completed with RESERVATION CONFLICT status.
+                */
+               if ((pr_res_holder->pr_res_type != type) ||
+                   (pr_res_holder->pr_res_scope != scope)) {
+                       struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;
+                       pr_err("SPC-3 PR: Attempted RESERVE from"
+                               " [%s]: %s trying to change TYPE and/or SCOPE,"
+                               " while reservation already held by [%s]: %s,"
+                               " returning RESERVATION_CONFLICT\n",
+                               cmd->se_tfo->get_fabric_name(),
+                               se_sess->se_node_acl->initiatorname,
+                               pr_res_nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
+                               pr_res_holder->pr_reg_nacl->initiatorname);
+
+                       spin_unlock(&dev->dev_reservation_lock);
+                       ret = TCM_RESERVATION_CONFLICT;
+                       goto out_put_pr_reg;
+               }
+               /*
+                * From spc4r17 Section 5.7.9: Reserving:
+                *
+                * If the device server receives a PERSISTENT RESERVE OUT
+                * command with RESERVE service action where the TYPE field and
+                * the SCOPE field contain the same values as the existing type
+                * and scope from a persistent reservation holder, it shall not
+                * make any change to the existing persistent reservation and
+                * shall completethe command with GOOD status.
+                */
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = 0;
+               goto out_put_pr_reg;
+       }
+       /*
+        * Otherwise, our *pr_reg becomes the PR reservation holder for said
+        * TYPE/SCOPE.  Also set the received scope and type in *pr_reg.
+        */
+       pr_reg->pr_res_scope = scope;
+       pr_reg->pr_res_type = type;
+       pr_reg->pr_res_holder = 1;
+       dev->dev_pr_res_holder = pr_reg;
+       core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);
+
+       pr_debug("SPC-3 PR [%s] Service Action: RESERVE created new"
+               " reservation holder TYPE: %s ALL_TG_PT: %d\n",
+               cmd->se_tfo->get_fabric_name(), core_scsi3_pr_dump_type(type),
+               (pr_reg->pr_reg_all_tg_pt) ? 1 : 0);
+       pr_debug("SPC-3 PR [%s] RESERVE Node: %s%s\n",
+                       cmd->se_tfo->get_fabric_name(),
+                       se_sess->se_node_acl->initiatorname,
+                       i_buf);
+       spin_unlock(&dev->dev_reservation_lock);
+
+       if (pr_tmpl->pr_aptpl_active)
+               core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
+
+       ret = 0;
+out_put_pr_reg:
+       core_scsi3_put_pr_reg(pr_reg);
+       return ret;
+}
+
+static sense_reason_t
+core_scsi3_emulate_pro_reserve(struct se_cmd *cmd, int type, int scope,
+               u64 res_key)
+{
+       switch (type) {
+       case PR_TYPE_WRITE_EXCLUSIVE:
+       case PR_TYPE_EXCLUSIVE_ACCESS:
+       case PR_TYPE_WRITE_EXCLUSIVE_REGONLY:
+       case PR_TYPE_EXCLUSIVE_ACCESS_REGONLY:
+       case PR_TYPE_WRITE_EXCLUSIVE_ALLREG:
+       case PR_TYPE_EXCLUSIVE_ACCESS_ALLREG:
+               return core_scsi3_pro_reserve(cmd, type, scope, res_key);
+       default:
+               pr_err("SPC-3 PR: Unknown Service Action RESERVE Type:"
+                       " 0x%02x\n", type);
+               return TCM_INVALID_CDB_FIELD;
+       }
+}
+
+/*
+ * Called with struct se_device->dev_reservation_lock held.
+ */
+static void __core_scsi3_complete_pro_release(
+       struct se_device *dev,
+       struct se_node_acl *se_nacl,
+       struct t10_pr_registration *pr_reg,
+       int explicit,
+       int unreg)
+{
+       const struct target_core_fabric_ops *tfo = se_nacl->se_tpg->se_tpg_tfo;
+       char i_buf[PR_REG_ISID_ID_LEN];
+       int pr_res_type = 0, pr_res_scope = 0;
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+       core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);
+       /*
+        * Go ahead and release the current PR reservation holder.
+        * If an All Registrants reservation is currently active and
+        * a unregister operation is requested, replace the current
+        * dev_pr_res_holder with another active registration.
+        */
+       if (dev->dev_pr_res_holder) {
+               pr_res_type = dev->dev_pr_res_holder->pr_res_type;
+               pr_res_scope = dev->dev_pr_res_holder->pr_res_scope;
+               dev->dev_pr_res_holder->pr_res_type = 0;
+               dev->dev_pr_res_holder->pr_res_scope = 0;
+               dev->dev_pr_res_holder->pr_res_holder = 0;
+               dev->dev_pr_res_holder = NULL;
+       }
+       if (!unreg)
+               goto out;
+
+       spin_lock(&dev->t10_pr.registration_lock);
+       list_del_init(&pr_reg->pr_reg_list);
+       /*
+        * If the I_T nexus is a reservation holder, the persistent reservation
+        * is of an all registrants type, and the I_T nexus is the last remaining
+        * registered I_T nexus, then the device server shall also release the
+        * persistent reservation.
+        */
+       if (!list_empty(&dev->t10_pr.registration_list) &&
+           ((pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
+            (pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG))) {
+               dev->dev_pr_res_holder =
+                       list_entry(dev->t10_pr.registration_list.next,
+                                  struct t10_pr_registration, pr_reg_list);
+               dev->dev_pr_res_holder->pr_res_type = pr_res_type;
+               dev->dev_pr_res_holder->pr_res_scope = pr_res_scope;
+               dev->dev_pr_res_holder->pr_res_holder = 1;
+       }
+       spin_unlock(&dev->t10_pr.registration_lock);
+out:
+       if (!dev->dev_pr_res_holder) {
+               pr_debug("SPC-3 PR [%s] Service Action: %s RELEASE cleared"
+                       " reservation holder TYPE: %s ALL_TG_PT: %d\n",
+                       tfo->get_fabric_name(), (explicit) ? "explicit" :
+                       "implicit", core_scsi3_pr_dump_type(pr_res_type),
+                       (pr_reg->pr_reg_all_tg_pt) ? 1 : 0);
+       }
+       pr_debug("SPC-3 PR [%s] RELEASE Node: %s%s\n",
+               tfo->get_fabric_name(), se_nacl->initiatorname,
+               i_buf);
+       /*
+        * Clear TYPE and SCOPE for the next PROUT Service Action: RESERVE
+        */
+       pr_reg->pr_res_holder = pr_reg->pr_res_type = pr_reg->pr_res_scope = 0;
+}
+
+static sense_reason_t
+core_scsi3_emulate_pro_release(struct se_cmd *cmd, int type, int scope,
+               u64 res_key)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_session *se_sess = cmd->se_sess;
+       struct se_lun *se_lun = cmd->se_lun;
+       struct t10_pr_registration *pr_reg, *pr_reg_p, *pr_res_holder;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       sense_reason_t ret = 0;
+
+       if (!se_sess || !se_lun) {
+               pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * Locate the existing *pr_reg via struct se_node_acl pointers
+        */
+       pr_reg = core_scsi3_locate_pr_reg(dev, se_sess->se_node_acl, se_sess);
+       if (!pr_reg) {
+               pr_err("SPC-3 PR: Unable to locate"
+                       " PR_REGISTERED *pr_reg for RELEASE\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * From spc4r17 Section 5.7.11.2 Releasing:
+        *
+        * If there is no persistent reservation or in response to a persistent
+        * reservation release request from a registered I_T nexus that is not a
+        * persistent reservation holder (see 5.7.10), the device server shall
+        * do the following:
+        *
+        *     a) Not release the persistent reservation, if any;
+        *     b) Not remove any registrations; and
+        *     c) Complete the command with GOOD status.
+        */
+       spin_lock(&dev->dev_reservation_lock);
+       pr_res_holder = dev->dev_pr_res_holder;
+       if (!pr_res_holder) {
+               /*
+                * No persistent reservation, return GOOD status.
+                */
+               spin_unlock(&dev->dev_reservation_lock);
+               goto out_put_pr_reg;
+       }
+
+       if (!is_reservation_holder(pr_res_holder, pr_reg)) {
+               /*
+                * Release request from a registered I_T nexus that is not a
+                * persistent reservation holder. return GOOD status.
+                */
+               spin_unlock(&dev->dev_reservation_lock);
+               goto out_put_pr_reg;
+       }
+
+       /*
+        * From spc4r17 Section 5.7.11.2 Releasing:
+        *
+        * Only the persistent reservation holder (see 5.7.10) is allowed to
+        * release a persistent reservation.
+        *
+        * An application client releases the persistent reservation by issuing
+        * a PERSISTENT RESERVE OUT command with RELEASE service action through
+        * an I_T nexus that is a persistent reservation holder with the
+        * following parameters:
+        *
+        *     a) RESERVATION KEY field set to the value of the reservation key
+        *        that is registered with the logical unit for the I_T nexus;
+        */
+       if (res_key != pr_reg->pr_res_key) {
+               pr_err("SPC-3 PR RELEASE: Received res_key: 0x%016Lx"
+                       " does not match existing SA REGISTER res_key:"
+                       " 0x%016Lx\n", res_key, pr_reg->pr_res_key);
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out_put_pr_reg;
+       }
+       /*
+        * From spc4r17 Section 5.7.11.2 Releasing and above:
+        *
+        * b) TYPE field and SCOPE field set to match the persistent
+        *    reservation being released.
+        */
+       if ((pr_res_holder->pr_res_type != type) ||
+           (pr_res_holder->pr_res_scope != scope)) {
+               struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;
+               pr_err("SPC-3 PR RELEASE: Attempted to release"
+                       " reservation from [%s]: %s with different TYPE "
+                       "and/or SCOPE  while reservation already held by"
+                       " [%s]: %s, returning RESERVATION_CONFLICT\n",
+                       cmd->se_tfo->get_fabric_name(),
+                       se_sess->se_node_acl->initiatorname,
+                       pr_res_nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
+                       pr_res_holder->pr_reg_nacl->initiatorname);
+
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out_put_pr_reg;
+       }
+       /*
+        * In response to a persistent reservation release request from the
+        * persistent reservation holder the device server shall perform a
+        * release by doing the following as an uninterrupted series of actions:
+        * a) Release the persistent reservation;
+        * b) Not remove any registration(s);
+        * c) If the released persistent reservation is a registrants only type
+        * or all registrants type persistent reservation,
+        *    the device server shall establish a unit attention condition for
+        *    the initiator port associated with every regis-
+        *    tered I_T nexus other than I_T nexus on which the PERSISTENT
+        *    RESERVE OUT command with RELEASE service action was received,
+        *    with the additional sense code set to RESERVATIONS RELEASED; and
+        * d) If the persistent reservation is of any other type, the device
+        *    server shall not establish a unit attention condition.
+        */
+       __core_scsi3_complete_pro_release(dev, se_sess->se_node_acl,
+                                         pr_reg, 1, 0);
+
+       spin_unlock(&dev->dev_reservation_lock);
+
+       if ((type != PR_TYPE_WRITE_EXCLUSIVE_REGONLY) &&
+           (type != PR_TYPE_EXCLUSIVE_ACCESS_REGONLY) &&
+           (type != PR_TYPE_WRITE_EXCLUSIVE_ALLREG) &&
+           (type != PR_TYPE_EXCLUSIVE_ACCESS_ALLREG)) {
+               /*
+                * If no UNIT ATTENTION conditions will be established for
+                * PR_TYPE_WRITE_EXCLUSIVE or PR_TYPE_EXCLUSIVE_ACCESS
+                * go ahead and check for APTPL=1 update+write below
+                */
+               goto write_aptpl;
+       }
+
+       spin_lock(&pr_tmpl->registration_lock);
+       list_for_each_entry(pr_reg_p, &pr_tmpl->registration_list,
+                       pr_reg_list) {
+               /*
+                * Do not establish a UNIT ATTENTION condition
+                * for the calling I_T Nexus
+                */
+               if (pr_reg_p == pr_reg)
+                       continue;
+
+               core_scsi3_ua_allocate(pr_reg_p->pr_reg_nacl,
+                               pr_reg_p->pr_res_mapped_lun,
+                               0x2A, ASCQ_2AH_RESERVATIONS_RELEASED);
+       }
+       spin_unlock(&pr_tmpl->registration_lock);
+
+write_aptpl:
+       if (pr_tmpl->pr_aptpl_active)
+               core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
+
+out_put_pr_reg:
+       core_scsi3_put_pr_reg(pr_reg);
+       return ret;
+}
+
+static sense_reason_t
+core_scsi3_emulate_pro_clear(struct se_cmd *cmd, u64 res_key)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_node_acl *pr_reg_nacl;
+       struct se_session *se_sess = cmd->se_sess;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_reg_n, *pr_res_holder;
+       u32 pr_res_mapped_lun = 0;
+       int calling_it_nexus = 0;
+       /*
+        * Locate the existing *pr_reg via struct se_node_acl pointers
+        */
+       pr_reg_n = core_scsi3_locate_pr_reg(cmd->se_dev,
+                       se_sess->se_node_acl, se_sess);
+       if (!pr_reg_n) {
+               pr_err("SPC-3 PR: Unable to locate"
+                       " PR_REGISTERED *pr_reg for CLEAR\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * From spc4r17 section 5.7.11.6, Clearing:
+        *
+        * Any application client may release the persistent reservation and
+        * remove all registrations from a device server by issuing a
+        * PERSISTENT RESERVE OUT command with CLEAR service action through a
+        * registered I_T nexus with the following parameter:
+        *
+        *      a) RESERVATION KEY field set to the value of the reservation key
+        *         that is registered with the logical unit for the I_T nexus.
+        */
+       if (res_key != pr_reg_n->pr_res_key) {
+               pr_err("SPC-3 PR REGISTER: Received"
+                       " res_key: 0x%016Lx does not match"
+                       " existing SA REGISTER res_key:"
+                       " 0x%016Lx\n", res_key, pr_reg_n->pr_res_key);
+               core_scsi3_put_pr_reg(pr_reg_n);
+               return TCM_RESERVATION_CONFLICT;
+       }
+       /*
+        * a) Release the persistent reservation, if any;
+        */
+       spin_lock(&dev->dev_reservation_lock);
+       pr_res_holder = dev->dev_pr_res_holder;
+       if (pr_res_holder) {
+               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, 0);
+       }
+       spin_unlock(&dev->dev_reservation_lock);
+       /*
+        * b) Remove all registration(s) (see spc4r17 5.7.7);
+        */
+       spin_lock(&pr_tmpl->registration_lock);
+       list_for_each_entry_safe(pr_reg, pr_reg_tmp,
+                       &pr_tmpl->registration_list, pr_reg_list) {
+
+               calling_it_nexus = (pr_reg_n == pr_reg) ? 1 : 0;
+               pr_reg_nacl = pr_reg->pr_reg_nacl;
+               pr_res_mapped_lun = pr_reg->pr_res_mapped_lun;
+               __core_scsi3_free_registration(dev, pr_reg, NULL,
+                                       calling_it_nexus);
+               /*
+                * e) Establish a unit attention condition for the initiator
+                *    port associated with every registered I_T nexus other
+                *    than the I_T nexus on which the PERSISTENT RESERVE OUT
+                *    command with CLEAR service action was received, with the
+                *    additional sense code set to RESERVATIONS PREEMPTED.
+                */
+               if (!calling_it_nexus)
+                       core_scsi3_ua_allocate(pr_reg_nacl, pr_res_mapped_lun,
+                               0x2A, ASCQ_2AH_RESERVATIONS_PREEMPTED);
+       }
+       spin_unlock(&pr_tmpl->registration_lock);
+
+       pr_debug("SPC-3 PR [%s] Service Action: CLEAR complete\n",
+               cmd->se_tfo->get_fabric_name());
+
+       core_scsi3_update_and_write_aptpl(cmd->se_dev, false);
+
+       core_scsi3_pr_generation(dev);
+       return 0;
+}
+
+/*
+ * Called with struct se_device->dev_reservation_lock held.
+ */
+static void __core_scsi3_complete_pro_preempt(
+       struct se_device *dev,
+       struct t10_pr_registration *pr_reg,
+       struct list_head *preempt_and_abort_list,
+       int type,
+       int scope,
+       enum preempt_type preempt_type)
+{
+       struct se_node_acl *nacl = pr_reg->pr_reg_nacl;
+       const struct target_core_fabric_ops *tfo = nacl->se_tpg->se_tpg_tfo;
+       char i_buf[PR_REG_ISID_ID_LEN];
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+       core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);
+       /*
+        * Do an implicit RELEASE of the existing reservation.
+        */
+       if (dev->dev_pr_res_holder)
+               __core_scsi3_complete_pro_release(dev, nacl,
+                                                 dev->dev_pr_res_holder, 0, 0);
+
+       dev->dev_pr_res_holder = pr_reg;
+       pr_reg->pr_res_holder = 1;
+       pr_reg->pr_res_type = type;
+       pr_reg->pr_res_scope = scope;
+
+       pr_debug("SPC-3 PR [%s] Service Action: PREEMPT%s created new"
+               " reservation holder TYPE: %s ALL_TG_PT: %d\n",
+               tfo->get_fabric_name(), (preempt_type == PREEMPT_AND_ABORT) ? "_AND_ABORT" : "",
+               core_scsi3_pr_dump_type(type),
+               (pr_reg->pr_reg_all_tg_pt) ? 1 : 0);
+       pr_debug("SPC-3 PR [%s] PREEMPT%s from Node: %s%s\n",
+               tfo->get_fabric_name(), (preempt_type == PREEMPT_AND_ABORT) ? "_AND_ABORT" : "",
+               nacl->initiatorname, i_buf);
+       /*
+        * For PREEMPT_AND_ABORT, add the preempting reservation's
+        * struct t10_pr_registration to the list that will be compared
+        * against received CDBs..
+        */
+       if (preempt_and_abort_list)
+               list_add_tail(&pr_reg->pr_reg_abort_list,
+                               preempt_and_abort_list);
+}
+
+static void core_scsi3_release_preempt_and_abort(
+       struct list_head *preempt_and_abort_list,
+       struct t10_pr_registration *pr_reg_holder)
+{
+       struct t10_pr_registration *pr_reg, *pr_reg_tmp;
+
+       list_for_each_entry_safe(pr_reg, pr_reg_tmp, preempt_and_abort_list,
+                               pr_reg_abort_list) {
+
+               list_del(&pr_reg->pr_reg_abort_list);
+               if (pr_reg_holder == pr_reg)
+                       continue;
+               if (pr_reg->pr_res_holder) {
+                       pr_warn("pr_reg->pr_res_holder still set\n");
+                       continue;
+               }
+
+               pr_reg->pr_reg_deve = NULL;
+               pr_reg->pr_reg_nacl = NULL;
+               kmem_cache_free(t10_pr_reg_cache, pr_reg);
+       }
+}
+
+static sense_reason_t
+core_scsi3_pro_preempt(struct se_cmd *cmd, int type, int scope, u64 res_key,
+               u64 sa_res_key, enum preempt_type preempt_type)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_node_acl *pr_reg_nacl;
+       struct se_session *se_sess = cmd->se_sess;
+       LIST_HEAD(preempt_and_abort_list);
+       struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_reg_n, *pr_res_holder;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       u32 pr_res_mapped_lun = 0;
+       int all_reg = 0, calling_it_nexus = 0;
+       bool sa_res_key_unmatched = sa_res_key != 0;
+       int prh_type = 0, prh_scope = 0;
+
+       if (!se_sess)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       pr_reg_n = core_scsi3_locate_pr_reg(cmd->se_dev, se_sess->se_node_acl,
+                               se_sess);
+       if (!pr_reg_n) {
+               pr_err("SPC-3 PR: Unable to locate"
+                       " PR_REGISTERED *pr_reg for PREEMPT%s\n",
+                       (preempt_type == PREEMPT_AND_ABORT) ? "_AND_ABORT" : "");
+               return TCM_RESERVATION_CONFLICT;
+       }
+       if (pr_reg_n->pr_res_key != res_key) {
+               core_scsi3_put_pr_reg(pr_reg_n);
+               return TCM_RESERVATION_CONFLICT;
+       }
+       if (scope != PR_SCOPE_LU_SCOPE) {
+               pr_err("SPC-3 PR: Illegal SCOPE: 0x%02x\n", scope);
+               core_scsi3_put_pr_reg(pr_reg_n);
+               return TCM_INVALID_PARAMETER_LIST;
+       }
+
+       spin_lock(&dev->dev_reservation_lock);
+       pr_res_holder = dev->dev_pr_res_holder;
+       if (pr_res_holder &&
+          ((pr_res_holder->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
+           (pr_res_holder->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG)))
+               all_reg = 1;
+
+       if (!all_reg && !sa_res_key) {
+               spin_unlock(&dev->dev_reservation_lock);
+               core_scsi3_put_pr_reg(pr_reg_n);
+               return TCM_INVALID_PARAMETER_LIST;
+       }
+       /*
+        * From spc4r17, section 5.7.11.4.4 Removing Registrations:
+        *
+        * If the SERVICE ACTION RESERVATION KEY field does not identify a
+        * persistent reservation holder or there is no persistent reservation
+        * holder (i.e., there is no persistent reservation), then the device
+        * server shall perform a preempt by doing the following in an
+        * uninterrupted series of actions. (See below..)
+        */
+       if (!pr_res_holder || (pr_res_holder->pr_res_key != sa_res_key)) {
+               /*
+                * No existing or SA Reservation Key matching reservations..
+                *
+                * PROUT SA PREEMPT with All Registrant type reservations are
+                * allowed to be processed without a matching SA Reservation Key
+                */
+               spin_lock(&pr_tmpl->registration_lock);
+               list_for_each_entry_safe(pr_reg, pr_reg_tmp,
+                               &pr_tmpl->registration_list, pr_reg_list) {
+                       /*
+                        * Removing of registrations in non all registrants
+                        * type reservations without a matching SA reservation
+                        * key.
+                        *
+                        * a) Remove the registrations for all I_T nexuses
+                        *    specified by the SERVICE ACTION RESERVATION KEY
+                        *    field;
+                        * b) Ignore the contents of the SCOPE and TYPE fields;
+                        * c) Process tasks as defined in 5.7.1; and
+                        * d) Establish a unit attention condition for the
+                        *    initiator port associated with every I_T nexus
+                        *    that lost its registration other than the I_T
+                        *    nexus on which the PERSISTENT RESERVE OUT command
+                        *    was received, with the additional sense code set
+                        *    to REGISTRATIONS PREEMPTED.
+                        */
+                       if (!all_reg) {
+                               if (pr_reg->pr_res_key != sa_res_key)
+                                       continue;
+                               sa_res_key_unmatched = false;
+
+                               calling_it_nexus = (pr_reg_n == pr_reg) ? 1 : 0;
+                               pr_reg_nacl = pr_reg->pr_reg_nacl;
+                               pr_res_mapped_lun = pr_reg->pr_res_mapped_lun;
+                               __core_scsi3_free_registration(dev, pr_reg,
+                                       (preempt_type == PREEMPT_AND_ABORT) ? &preempt_and_abort_list :
+                                               NULL, calling_it_nexus);
+                       } else {
+                               /*
+                                * Case for any existing all registrants type
+                                * reservation, follow logic in spc4r17 section
+                                * 5.7.11.4 Preempting, Table 52 and Figure 7.
+                                *
+                                * For a ZERO SA Reservation key, release
+                                * all other registrations and do an implicit
+                                * release of active persistent reservation.
+                                *
+                                * For a non-ZERO SA Reservation key, only
+                                * release the matching reservation key from
+                                * registrations.
+                                */
+                               if ((sa_res_key) &&
+                                    (pr_reg->pr_res_key != sa_res_key))
+                                       continue;
+                               sa_res_key_unmatched = false;
+
+                               calling_it_nexus = (pr_reg_n == pr_reg) ? 1 : 0;
+                               if (calling_it_nexus)
+                                       continue;
+
+                               pr_reg_nacl = pr_reg->pr_reg_nacl;
+                               pr_res_mapped_lun = pr_reg->pr_res_mapped_lun;
+                               __core_scsi3_free_registration(dev, pr_reg,
+                                       (preempt_type == PREEMPT_AND_ABORT) ? &preempt_and_abort_list :
+                                               NULL, 0);
+                       }
+                       if (!calling_it_nexus)
+                               core_scsi3_ua_allocate(pr_reg_nacl,
+                                       pr_res_mapped_lun, 0x2A,
+                                       ASCQ_2AH_REGISTRATIONS_PREEMPTED);
+               }
+               spin_unlock(&pr_tmpl->registration_lock);
+               /*
+                * If a PERSISTENT RESERVE OUT with a PREEMPT service action or
+                * a PREEMPT AND ABORT service action sets the SERVICE ACTION
+                * RESERVATION KEY field to a value that does not match any
+                * registered reservation key, then the device server shall
+                * complete the command with RESERVATION CONFLICT status.
+                */
+               if (sa_res_key_unmatched) {
+                       spin_unlock(&dev->dev_reservation_lock);
+                       core_scsi3_put_pr_reg(pr_reg_n);
+                       return TCM_RESERVATION_CONFLICT;
+               }
+               /*
+                * For an existing all registrants type reservation
+                * with a zero SA rservation key, preempt the existing
+                * reservation with the new PR type and scope.
+                */
+               if (pr_res_holder && all_reg && !(sa_res_key)) {
+                       __core_scsi3_complete_pro_preempt(dev, pr_reg_n,
+                               (preempt_type == PREEMPT_AND_ABORT) ? &preempt_and_abort_list : NULL,
+                               type, scope, preempt_type);
+
+                       if (preempt_type == PREEMPT_AND_ABORT)
+                               core_scsi3_release_preempt_and_abort(
+                                       &preempt_and_abort_list, pr_reg_n);
+               }
+               spin_unlock(&dev->dev_reservation_lock);
+
+               if (pr_tmpl->pr_aptpl_active)
+                       core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
+
+               core_scsi3_put_pr_reg(pr_reg_n);
+               core_scsi3_pr_generation(cmd->se_dev);
+               return 0;
+       }
+       /*
+        * The PREEMPTing SA reservation key matches that of the
+        * existing persistent reservation, first, we check if
+        * we are preempting our own reservation.
+        * From spc4r17, section 5.7.11.4.3 Preempting
+        * persistent reservations and registration handling
+        *
+        * If an all registrants persistent reservation is not
+        * present, it is not an error for the persistent
+        * reservation holder to preempt itself (i.e., a
+        * PERSISTENT RESERVE OUT with a PREEMPT service action
+        * or a PREEMPT AND ABORT service action with the
+        * SERVICE ACTION RESERVATION KEY value equal to the
+        * persistent reservation holder's reservation key that
+        * is received from the persistent reservation holder).
+        * In that case, the device server shall establish the
+        * new persistent reservation and maintain the
+        * registration.
+        */
+       prh_type = pr_res_holder->pr_res_type;
+       prh_scope = pr_res_holder->pr_res_scope;
+       /*
+        * If the SERVICE ACTION RESERVATION KEY field identifies a
+        * persistent reservation holder (see 5.7.10), the device
+        * server shall perform a preempt by doing the following as
+        * an uninterrupted series of actions:
+        *
+        * a) Release the persistent reservation for the holder
+        *    identified by the SERVICE ACTION RESERVATION KEY field;
+        */
+       if (pr_reg_n != pr_res_holder)
+               __core_scsi3_complete_pro_release(dev,
+                                                 pr_res_holder->pr_reg_nacl,
+                                                 dev->dev_pr_res_holder, 0, 0);
+       /*
+        * b) Remove the registrations for all I_T nexuses identified
+        *    by the SERVICE ACTION RESERVATION KEY field, except the
+        *    I_T nexus that is being used for the PERSISTENT RESERVE
+        *    OUT command. If an all registrants persistent reservation
+        *    is present and the SERVICE ACTION RESERVATION KEY field
+        *    is set to zero, then all registrations shall be removed
+        *    except for that of the I_T nexus that is being used for
+        *    the PERSISTENT RESERVE OUT command;
+        */
+       spin_lock(&pr_tmpl->registration_lock);
+       list_for_each_entry_safe(pr_reg, pr_reg_tmp,
+                       &pr_tmpl->registration_list, pr_reg_list) {
+
+               calling_it_nexus = (pr_reg_n == pr_reg) ? 1 : 0;
+               if (calling_it_nexus)
+                       continue;
+
+               if (pr_reg->pr_res_key != sa_res_key)
+                       continue;
+
+               pr_reg_nacl = pr_reg->pr_reg_nacl;
+               pr_res_mapped_lun = pr_reg->pr_res_mapped_lun;
+               __core_scsi3_free_registration(dev, pr_reg,
+                               (preempt_type == PREEMPT_AND_ABORT) ? &preempt_and_abort_list : NULL,
+                               calling_it_nexus);
+               /*
+                * e) Establish a unit attention condition for the initiator
+                *    port associated with every I_T nexus that lost its
+                *    persistent reservation and/or registration, with the
+                *    additional sense code set to REGISTRATIONS PREEMPTED;
+                */
+               core_scsi3_ua_allocate(pr_reg_nacl, pr_res_mapped_lun, 0x2A,
+                               ASCQ_2AH_REGISTRATIONS_PREEMPTED);
+       }
+       spin_unlock(&pr_tmpl->registration_lock);
+       /*
+        * c) Establish a persistent reservation for the preempting
+        *    I_T nexus using the contents of the SCOPE and TYPE fields;
+        */
+       __core_scsi3_complete_pro_preempt(dev, pr_reg_n,
+                       (preempt_type == PREEMPT_AND_ABORT) ? &preempt_and_abort_list : NULL,
+                       type, scope, preempt_type);
+       /*
+        * d) Process tasks as defined in 5.7.1;
+        * e) See above..
+        * f) If the type or scope has changed, then for every I_T nexus
+        *    whose reservation key was not removed, except for the I_T
+        *    nexus on which the PERSISTENT RESERVE OUT command was
+        *    received, the device server shall establish a unit
+        *    attention condition for the initiator port associated with
+        *    that I_T nexus, with the additional sense code set to
+        *    RESERVATIONS RELEASED. If the type or scope have not
+        *    changed, then no unit attention condition(s) shall be
+        *    established for this reason.
+        */
+       if ((prh_type != type) || (prh_scope != scope)) {
+               spin_lock(&pr_tmpl->registration_lock);
+               list_for_each_entry_safe(pr_reg, pr_reg_tmp,
+                               &pr_tmpl->registration_list, pr_reg_list) {
+
+                       calling_it_nexus = (pr_reg_n == pr_reg) ? 1 : 0;
+                       if (calling_it_nexus)
+                               continue;
+
+                       core_scsi3_ua_allocate(pr_reg->pr_reg_nacl,
+                                       pr_reg->pr_res_mapped_lun, 0x2A,
+                                       ASCQ_2AH_RESERVATIONS_RELEASED);
+               }
+               spin_unlock(&pr_tmpl->registration_lock);
+       }
+       spin_unlock(&dev->dev_reservation_lock);
+       /*
+        * Call LUN_RESET logic upon list of struct t10_pr_registration,
+        * All received CDBs for the matching existing reservation and
+        * registrations undergo ABORT_TASK logic.
+        *
+        * From there, core_scsi3_release_preempt_and_abort() will
+        * release every registration in the list (which have already
+        * been removed from the primary pr_reg list), except the
+        * new persistent reservation holder, the calling Initiator Port.
+        */
+       if (preempt_type == PREEMPT_AND_ABORT) {
+               core_tmr_lun_reset(dev, NULL, &preempt_and_abort_list, cmd);
+               core_scsi3_release_preempt_and_abort(&preempt_and_abort_list,
+                                               pr_reg_n);
+       }
+
+       if (pr_tmpl->pr_aptpl_active)
+               core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
+
+       core_scsi3_put_pr_reg(pr_reg_n);
+       core_scsi3_pr_generation(cmd->se_dev);
+       return 0;
+}
+
+static sense_reason_t
+core_scsi3_emulate_pro_preempt(struct se_cmd *cmd, int type, int scope,
+               u64 res_key, u64 sa_res_key, enum preempt_type preempt_type)
+{
+       switch (type) {
+       case PR_TYPE_WRITE_EXCLUSIVE:
+       case PR_TYPE_EXCLUSIVE_ACCESS:
+       case PR_TYPE_WRITE_EXCLUSIVE_REGONLY:
+       case PR_TYPE_EXCLUSIVE_ACCESS_REGONLY:
+       case PR_TYPE_WRITE_EXCLUSIVE_ALLREG:
+       case PR_TYPE_EXCLUSIVE_ACCESS_ALLREG:
+               return core_scsi3_pro_preempt(cmd, type, scope, res_key,
+                                             sa_res_key, preempt_type);
+       default:
+               pr_err("SPC-3 PR: Unknown Service Action PREEMPT%s"
+                       " Type: 0x%02x\n", (preempt_type == PREEMPT_AND_ABORT) ? "_AND_ABORT" : "", type);
+               return TCM_INVALID_CDB_FIELD;
+       }
+}
+
+
+static sense_reason_t
+core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key,
+               u64 sa_res_key, int aptpl, int unreg)
+{
+       struct se_session *se_sess = cmd->se_sess;
+       struct se_device *dev = cmd->se_dev;
+       struct se_dev_entry *dest_se_deve = NULL;
+       struct se_lun *se_lun = cmd->se_lun;
+       struct se_node_acl *pr_res_nacl, *pr_reg_nacl, *dest_node_acl = NULL;
+       struct se_port *se_port;
+       struct se_portal_group *se_tpg, *dest_se_tpg = NULL;
+       const struct target_core_fabric_ops *dest_tf_ops = NULL, *tf_ops;
+       struct t10_pr_registration *pr_reg, *pr_res_holder, *dest_pr_reg;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       unsigned char *buf;
+       unsigned char *initiator_str;
+       char *iport_ptr = NULL, i_buf[PR_REG_ISID_ID_LEN];
+       u32 tid_len, tmp_tid_len;
+       int new_reg = 0, type, scope, matching_iname;
+       sense_reason_t ret;
+       unsigned short rtpi;
+       unsigned char proto_ident;
+
+       if (!se_sess || !se_lun) {
+               pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+
+       memset(i_buf, 0, PR_REG_ISID_ID_LEN);
+       se_tpg = se_sess->se_tpg;
+       tf_ops = se_tpg->se_tpg_tfo;
+       /*
+        * Follow logic from spc4r17 Section 5.7.8, Table 50 --
+        *      Register behaviors for a REGISTER AND MOVE service action
+        *
+        * Locate the existing *pr_reg via struct se_node_acl pointers
+        */
+       pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev, se_sess->se_node_acl,
+                               se_sess);
+       if (!pr_reg) {
+               pr_err("SPC-3 PR: Unable to locate PR_REGISTERED"
+                       " *pr_reg for REGISTER_AND_MOVE\n");
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+       }
+       /*
+        * The provided reservation key much match the existing reservation key
+        * provided during this initiator's I_T nexus registration.
+        */
+       if (res_key != pr_reg->pr_res_key) {
+               pr_warn("SPC-3 PR REGISTER_AND_MOVE: Received"
+                       " res_key: 0x%016Lx does not match existing SA REGISTER"
+                       " res_key: 0x%016Lx\n", res_key, pr_reg->pr_res_key);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out_put_pr_reg;
+       }
+       /*
+        * The service active reservation key needs to be non zero
+        */
+       if (!sa_res_key) {
+               pr_warn("SPC-3 PR REGISTER_AND_MOVE: Received zero"
+                       " sa_res_key\n");
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out_put_pr_reg;
+       }
+
+       /*
+        * Determine the Relative Target Port Identifier where the reservation
+        * will be moved to for the TransportID containing SCSI initiator WWN
+        * information.
+        */
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf) {
+               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               goto out_put_pr_reg;
+       }
+
+       rtpi = (buf[18] & 0xff) << 8;
+       rtpi |= buf[19] & 0xff;
+       tid_len = (buf[20] & 0xff) << 24;
+       tid_len |= (buf[21] & 0xff) << 16;
+       tid_len |= (buf[22] & 0xff) << 8;
+       tid_len |= buf[23] & 0xff;
+       transport_kunmap_data_sg(cmd);
+       buf = NULL;
+
+       if ((tid_len + 24) != cmd->data_length) {
+               pr_err("SPC-3 PR: Illegal tid_len: %u + 24 byte header"
+                       " does not equal CDB data_length: %u\n", tid_len,
+                       cmd->data_length);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out_put_pr_reg;
+       }
+
+       spin_lock(&dev->se_port_lock);
+       list_for_each_entry(se_port, &dev->dev_sep_list, sep_list) {
+               if (se_port->sep_rtpi != rtpi)
+                       continue;
+               dest_se_tpg = se_port->sep_tpg;
+               if (!dest_se_tpg)
+                       continue;
+               dest_tf_ops = dest_se_tpg->se_tpg_tfo;
+               if (!dest_tf_ops)
+                       continue;
+
+               atomic_inc_mb(&dest_se_tpg->tpg_pr_ref_count);
+               spin_unlock(&dev->se_port_lock);
+
+               if (core_scsi3_tpg_depend_item(dest_se_tpg)) {
+                       pr_err("core_scsi3_tpg_depend_item() failed"
+                               " for dest_se_tpg\n");
+                       atomic_dec_mb(&dest_se_tpg->tpg_pr_ref_count);
+                       ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                       goto out_put_pr_reg;
+               }
+
+               spin_lock(&dev->se_port_lock);
+               break;
+       }
+       spin_unlock(&dev->se_port_lock);
+
+       if (!dest_se_tpg || !dest_tf_ops) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: Unable to locate"
+                       " fabric ops from Relative Target Port Identifier:"
+                       " %hu\n", rtpi);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out_put_pr_reg;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf) {
+               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               goto out_put_pr_reg;
+       }
+       proto_ident = (buf[24] & 0x0f);
+
+       pr_debug("SPC-3 PR REGISTER_AND_MOVE: Extracted Protocol Identifier:"
+                       " 0x%02x\n", proto_ident);
+
+       if (proto_ident != dest_tf_ops->get_fabric_proto_ident(dest_se_tpg)) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: Received"
+                       " proto_ident: 0x%02x does not match ident: 0x%02x"
+                       " from fabric: %s\n", proto_ident,
+                       dest_tf_ops->get_fabric_proto_ident(dest_se_tpg),
+                       dest_tf_ops->get_fabric_name());
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+       if (dest_tf_ops->tpg_parse_pr_out_transport_id == NULL) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: Fabric does not"
+                       " containg a valid tpg_parse_pr_out_transport_id"
+                       " function pointer\n");
+               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               goto out;
+       }
+       initiator_str = dest_tf_ops->tpg_parse_pr_out_transport_id(dest_se_tpg,
+                       (const char *)&buf[24], &tmp_tid_len, &iport_ptr);
+       if (!initiator_str) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: Unable to locate"
+                       " initiator_str from Transport ID\n");
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       transport_kunmap_data_sg(cmd);
+       buf = NULL;
+
+       pr_debug("SPC-3 PR [%s] Extracted initiator %s identifier: %s"
+               " %s\n", dest_tf_ops->get_fabric_name(), (iport_ptr != NULL) ?
+               "port" : "device", initiator_str, (iport_ptr != NULL) ?
+               iport_ptr : "");
+       /*
+        * If a PERSISTENT RESERVE OUT command with a REGISTER AND MOVE service
+        * action specifies a TransportID that is the same as the initiator port
+        * of the I_T nexus for the command received, 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.
+        */
+       pr_reg_nacl = pr_reg->pr_reg_nacl;
+       matching_iname = (!strcmp(initiator_str,
+                                 pr_reg_nacl->initiatorname)) ? 1 : 0;
+       if (!matching_iname)
+               goto after_iport_check;
+
+       if (!iport_ptr || !pr_reg->isid_present_at_reg) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: TransportID: %s"
+                       " matches: %s on received I_T Nexus\n", initiator_str,
+                       pr_reg_nacl->initiatorname);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+       if (!strcmp(iport_ptr, pr_reg->pr_reg_isid)) {
+               pr_err("SPC-3 PR REGISTER_AND_MOVE: TransportID: %s %s"
+                       " matches: %s %s on received I_T Nexus\n",
+                       initiator_str, iport_ptr, pr_reg_nacl->initiatorname,
+                       pr_reg->pr_reg_isid);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+after_iport_check:
+       /*
+        * Locate the destination struct se_node_acl from the received Transport ID
+        */
+       spin_lock_irq(&dest_se_tpg->acl_node_lock);
+       dest_node_acl = __core_tpg_get_initiator_node_acl(dest_se_tpg,
+                               initiator_str);
+       if (dest_node_acl)
+               atomic_inc_mb(&dest_node_acl->acl_pr_ref_count);
+       spin_unlock_irq(&dest_se_tpg->acl_node_lock);
+
+       if (!dest_node_acl) {
+               pr_err("Unable to locate %s dest_node_acl for"
+                       " TransportID%s\n", dest_tf_ops->get_fabric_name(),
+                       initiator_str);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       if (core_scsi3_nodeacl_depend_item(dest_node_acl)) {
+               pr_err("core_scsi3_nodeacl_depend_item() for"
+                       " dest_node_acl\n");
+               atomic_dec_mb(&dest_node_acl->acl_pr_ref_count);
+               dest_node_acl = NULL;
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       pr_debug("SPC-3 PR REGISTER_AND_MOVE: Found %s dest_node_acl:"
+               " %s from TransportID\n", dest_tf_ops->get_fabric_name(),
+               dest_node_acl->initiatorname);
+
+       /*
+        * Locate the struct se_dev_entry pointer for the matching RELATIVE TARGET
+        * PORT IDENTIFIER.
+        */
+       dest_se_deve = core_get_se_deve_from_rtpi(dest_node_acl, rtpi);
+       if (!dest_se_deve) {
+               pr_err("Unable to locate %s dest_se_deve from RTPI:"
+                       " %hu\n",  dest_tf_ops->get_fabric_name(), rtpi);
+               ret = TCM_INVALID_PARAMETER_LIST;
+               goto out;
+       }
+
+       if (core_scsi3_lunacl_depend_item(dest_se_deve)) {
+               pr_err("core_scsi3_lunacl_depend_item() failed\n");
+               atomic_dec_mb(&dest_se_deve->pr_ref_count);
+               dest_se_deve = NULL;
+               ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               goto out;
+       }
+
+       pr_debug("SPC-3 PR REGISTER_AND_MOVE: Located %s node %s LUN"
+               " ACL for dest_se_deve->mapped_lun: %u\n",
+               dest_tf_ops->get_fabric_name(), dest_node_acl->initiatorname,
+               dest_se_deve->mapped_lun);
+
+       /*
+        * A persistent reservation needs to already existing in order to
+        * successfully complete the REGISTER_AND_MOVE service action..
+        */
+       spin_lock(&dev->dev_reservation_lock);
+       pr_res_holder = dev->dev_pr_res_holder;
+       if (!pr_res_holder) {
+               pr_warn("SPC-3 PR REGISTER_AND_MOVE: No reservation"
+                       " currently held\n");
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = TCM_INVALID_CDB_FIELD;
+               goto out;
+       }
+       /*
+        * The received on I_T Nexus must be the reservation holder.
+        *
+        * From spc4r17 section 5.7.8  Table 50 --
+        *      Register behaviors for a REGISTER AND MOVE service action
+        */
+       if (!is_reservation_holder(pr_res_holder, pr_reg)) {
+               pr_warn("SPC-3 PR REGISTER_AND_MOVE: Calling I_T"
+                       " Nexus is not reservation holder\n");
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out;
+       }
+       /*
+        * From spc4r17 section 5.7.8: registering and moving reservation
+        *
+        * If a PERSISTENT RESERVE OUT command with a REGISTER AND MOVE service
+        * action is received and the established persistent reservation is a
+        * Write Exclusive - All Registrants type or Exclusive Access -
+        * All Registrants type reservation, then the command shall be completed
+        * with RESERVATION CONFLICT status.
+        */
+       if ((pr_res_holder->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
+           (pr_res_holder->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG)) {
+               pr_warn("SPC-3 PR REGISTER_AND_MOVE: Unable to move"
+                       " reservation for type: %s\n",
+                       core_scsi3_pr_dump_type(pr_res_holder->pr_res_type));
+               spin_unlock(&dev->dev_reservation_lock);
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out;
+       }
+       pr_res_nacl = pr_res_holder->pr_reg_nacl;
+       /*
+        * b) Ignore the contents of the (received) SCOPE and TYPE fields;
+        */
+       type = pr_res_holder->pr_res_type;
+       scope = pr_res_holder->pr_res_type;
+       /*
+        * c) Associate the reservation key specified in the SERVICE ACTION
+        *    RESERVATION KEY field with the I_T nexus specified as the
+        *    destination of the register and move, where:
+        *    A) The I_T nexus is specified by the TransportID and the
+        *       RELATIVE TARGET PORT IDENTIFIER field (see 6.14.4); and
+        *    B) Regardless of the TransportID format used, the association for
+        *       the initiator port is based on either the initiator port name
+        *       (see 3.1.71) on SCSI transport protocols where port names are
+        *       required or the initiator port identifier (see 3.1.70) on SCSI
+        *       transport protocols where port names are not required;
+        * d) Register the reservation key specified in the SERVICE ACTION
+        *    RESERVATION KEY field;
+        * e) Retain the reservation key specified in the SERVICE ACTION
+        *    RESERVATION KEY field and associated information;
+        *
+        * Also, It is not an error for a REGISTER AND MOVE service action to
+        * register an I_T nexus that is already registered with the same
+        * reservation key or a different reservation key.
+        */
+       dest_pr_reg = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
+                                       iport_ptr);
+       if (!dest_pr_reg) {
+               if (core_scsi3_alloc_registration(cmd->se_dev,
+                               dest_node_acl, dest_se_deve, iport_ptr,
+                               sa_res_key, 0, aptpl, 2, 1)) {
+                       spin_unlock(&dev->dev_reservation_lock);
+                       ret = TCM_INVALID_PARAMETER_LIST;
+                       goto out;
+               }
+               dest_pr_reg = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
+                                               iport_ptr);
+               new_reg = 1;
+       }
+       /*
+        * f) Release the persistent reservation for the persistent reservation
+        *    holder (i.e., the I_T nexus on which the
+        */
+       __core_scsi3_complete_pro_release(dev, pr_res_nacl,
+                                         dev->dev_pr_res_holder, 0, 0);
+       /*
+        * g) Move the persistent reservation to the specified I_T nexus using
+        *    the same scope and type as the persistent reservation released in
+        *    item f); and
+        */
+       dev->dev_pr_res_holder = dest_pr_reg;
+       dest_pr_reg->pr_res_holder = 1;
+       dest_pr_reg->pr_res_type = type;
+       pr_reg->pr_res_scope = scope;
+       core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);
+       /*
+        * Increment PRGeneration for existing registrations..
+        */
+       if (!new_reg)
+               dest_pr_reg->pr_res_generation = pr_tmpl->pr_generation++;
+       spin_unlock(&dev->dev_reservation_lock);
+
+       pr_debug("SPC-3 PR [%s] Service Action: REGISTER_AND_MOVE"
+               " created new reservation holder TYPE: %s on object RTPI:"
+               " %hu  PRGeneration: 0x%08x\n", dest_tf_ops->get_fabric_name(),
+               core_scsi3_pr_dump_type(type), rtpi,
+               dest_pr_reg->pr_res_generation);
+       pr_debug("SPC-3 PR Successfully moved reservation from"
+               " %s Fabric Node: %s%s -> %s Fabric Node: %s %s\n",
+               tf_ops->get_fabric_name(), pr_reg_nacl->initiatorname,
+               i_buf, dest_tf_ops->get_fabric_name(),
+               dest_node_acl->initiatorname, (iport_ptr != NULL) ?
+               iport_ptr : "");
+       /*
+        * It is now safe to release configfs group dependencies for destination
+        * of Transport ID Initiator Device/Port Identifier
+        */
+       core_scsi3_lunacl_undepend_item(dest_se_deve);
+       core_scsi3_nodeacl_undepend_item(dest_node_acl);
+       core_scsi3_tpg_undepend_item(dest_se_tpg);
+       /*
+        * h) If the UNREG bit is set to one, unregister (see 5.7.11.3) the I_T
+        * nexus on which PERSISTENT RESERVE OUT command was received.
+        */
+       if (unreg) {
+               spin_lock(&pr_tmpl->registration_lock);
+               __core_scsi3_free_registration(dev, pr_reg, NULL, 1);
+               spin_unlock(&pr_tmpl->registration_lock);
+       } else
+               core_scsi3_put_pr_reg(pr_reg);
+
+       core_scsi3_update_and_write_aptpl(cmd->se_dev, aptpl);
+
+       transport_kunmap_data_sg(cmd);
+
+       core_scsi3_put_pr_reg(dest_pr_reg);
+       return 0;
+out:
+       if (buf)
+               transport_kunmap_data_sg(cmd);
+       if (dest_se_deve)
+               core_scsi3_lunacl_undepend_item(dest_se_deve);
+       if (dest_node_acl)
+               core_scsi3_nodeacl_undepend_item(dest_node_acl);
+       core_scsi3_tpg_undepend_item(dest_se_tpg);
+
+out_put_pr_reg:
+       core_scsi3_put_pr_reg(pr_reg);
+       return ret;
+}
+
+static unsigned long long core_scsi3_extract_reservation_key(unsigned char *cdb)
+{
+       unsigned int __v1, __v2;
+
+       __v1 = (cdb[0] << 24) | (cdb[1] << 16) | (cdb[2] << 8) | cdb[3];
+       __v2 = (cdb[4] << 24) | (cdb[5] << 16) | (cdb[6] << 8) | cdb[7];
+
+       return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+/*
+ * See spc4r17 section 6.14 Table 170
+ */
+sense_reason_t
+target_scsi3_emulate_pr_out(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       unsigned char *cdb = &cmd->t_task_cdb[0];
+       unsigned char *buf;
+       u64 res_key, sa_res_key;
+       int sa, scope, type, aptpl;
+       int spec_i_pt = 0, all_tg_pt = 0, unreg = 0;
+       sense_reason_t ret;
+
+       /*
+        * Following spc2r20 5.5.1 Reservations overview:
+        *
+        * If a logical unit has been reserved by any RESERVE command and is
+        * still reserved by any initiator, all PERSISTENT RESERVE IN and all
+        * PERSISTENT RESERVE OUT commands shall conflict regardless of
+        * initiator or service action and shall terminate with a RESERVATION
+        * CONFLICT status.
+        */
+       if (cmd->se_dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS) {
+               pr_err("Received PERSISTENT_RESERVE CDB while legacy"
+                       " SPC-2 reservation is held, returning"
+                       " RESERVATION_CONFLICT\n");
+               return TCM_RESERVATION_CONFLICT;
+       }
+
+       /*
+        * FIXME: A NULL struct se_session pointer means an this is not coming from
+        * a $FABRIC_MOD's nexus, but from internal passthrough ops.
+        */
+       if (!cmd->se_sess)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       if (cmd->data_length < 24) {
+               pr_warn("SPC-PR: Received PR OUT parameter list"
+                       " length too small: %u\n", cmd->data_length);
+               return TCM_INVALID_PARAMETER_LIST;
+       }
+
+       /*
+        * From the PERSISTENT_RESERVE_OUT command descriptor block (CDB)
+        */
+       sa = (cdb[1] & 0x1f);
+       scope = (cdb[2] & 0xf0);
+       type = (cdb[2] & 0x0f);
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       /*
+        * From PERSISTENT_RESERVE_OUT parameter list (payload)
+        */
+       res_key = core_scsi3_extract_reservation_key(&buf[0]);
+       sa_res_key = core_scsi3_extract_reservation_key(&buf[8]);
+       /*
+        * REGISTER_AND_MOVE uses a different SA parameter list containing
+        * SCSI TransportIDs.
+        */
+       if (sa != PRO_REGISTER_AND_MOVE) {
+               spec_i_pt = (buf[20] & 0x08);
+               all_tg_pt = (buf[20] & 0x04);
+               aptpl = (buf[20] & 0x01);
+       } else {
+               aptpl = (buf[17] & 0x01);
+               unreg = (buf[17] & 0x02);
+       }
+       /*
+        * If the backend device has been configured to force APTPL metadata
+        * write-out, go ahead and propigate aptpl=1 down now.
+        */
+       if (dev->dev_attrib.force_pr_aptpl)
+               aptpl = 1;
+
+       transport_kunmap_data_sg(cmd);
+       buf = NULL;
+
+       /*
+        * SPEC_I_PT=1 is only valid for Service action: REGISTER
+        */
+       if (spec_i_pt && ((cdb[1] & 0x1f) != PRO_REGISTER))
+               return TCM_INVALID_PARAMETER_LIST;
+
+       /*
+        * From spc4r17 section 6.14:
+        *
+        * If the SPEC_I_PT bit is set to zero, the service action is not
+        * REGISTER AND MOVE, and the parameter list length is not 24, 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 PARAMETER LIST LENGTH ERROR.
+        */
+       if (!spec_i_pt && ((cdb[1] & 0x1f) != PRO_REGISTER_AND_MOVE) &&
+           (cmd->data_length != 24)) {
+               pr_warn("SPC-PR: Received PR OUT illegal parameter"
+                       " list length: %u\n", cmd->data_length);
+               return TCM_INVALID_PARAMETER_LIST;
+       }
+
+       /*
+        * (core_scsi3_emulate_pro_* function parameters
+        * are defined by spc4r17 Table 174:
+        * PERSISTENT_RESERVE_OUT service actions and valid parameters.
+        */
+       switch (sa) {
+       case PRO_REGISTER:
+               ret = core_scsi3_emulate_pro_register(cmd,
+                       res_key, sa_res_key, aptpl, all_tg_pt, spec_i_pt, REGISTER);
+               break;
+       case PRO_RESERVE:
+               ret = core_scsi3_emulate_pro_reserve(cmd, type, scope, res_key);
+               break;
+       case PRO_RELEASE:
+               ret = core_scsi3_emulate_pro_release(cmd, type, scope, res_key);
+               break;
+       case PRO_CLEAR:
+               ret = core_scsi3_emulate_pro_clear(cmd, res_key);
+               break;
+       case PRO_PREEMPT:
+               ret = core_scsi3_emulate_pro_preempt(cmd, type, scope,
+                                       res_key, sa_res_key, PREEMPT);
+               break;
+       case PRO_PREEMPT_AND_ABORT:
+               ret = core_scsi3_emulate_pro_preempt(cmd, type, scope,
+                                       res_key, sa_res_key, PREEMPT_AND_ABORT);
+               break;
+       case PRO_REGISTER_AND_IGNORE_EXISTING_KEY:
+               ret = core_scsi3_emulate_pro_register(cmd,
+                       0, sa_res_key, aptpl, all_tg_pt, spec_i_pt, REGISTER_AND_IGNORE_EXISTING_KEY);
+               break;
+       case PRO_REGISTER_AND_MOVE:
+               ret = core_scsi3_emulate_pro_register_and_move(cmd, res_key,
+                               sa_res_key, aptpl, unreg);
+               break;
+       default:
+               pr_err("Unknown PERSISTENT_RESERVE_OUT service"
+                       " action: 0x%02x\n", cdb[1] & 0x1f);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       if (!ret)
+               target_complete_cmd(cmd, GOOD);
+       return ret;
+}
+
+/*
+ * PERSISTENT_RESERVE_IN Service Action READ_KEYS
+ *
+ * See spc4r17 section 5.7.6.2 and section 6.13.2, Table 160
+ */
+static sense_reason_t
+core_scsi3_pri_read_keys(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct t10_pr_registration *pr_reg;
+       unsigned char *buf;
+       u32 add_len = 0, off = 8;
+
+       if (cmd->data_length < 8) {
+               pr_err("PRIN SA READ_KEYS SCSI Data Length: %u"
+                       " too small\n", cmd->data_length);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       buf[0] = ((dev->t10_pr.pr_generation >> 24) & 0xff);
+       buf[1] = ((dev->t10_pr.pr_generation >> 16) & 0xff);
+       buf[2] = ((dev->t10_pr.pr_generation >> 8) & 0xff);
+       buf[3] = (dev->t10_pr.pr_generation & 0xff);
+
+       spin_lock(&dev->t10_pr.registration_lock);
+       list_for_each_entry(pr_reg, &dev->t10_pr.registration_list,
+                       pr_reg_list) {
+               /*
+                * Check for overflow of 8byte PRI READ_KEYS payload and
+                * next reservation key list descriptor.
+                */
+               if ((add_len + 8) > (cmd->data_length - 8))
+                       break;
+
+               buf[off++] = ((pr_reg->pr_res_key >> 56) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 48) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 40) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 32) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 24) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 16) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 8) & 0xff);
+               buf[off++] = (pr_reg->pr_res_key & 0xff);
+
+               add_len += 8;
+       }
+       spin_unlock(&dev->t10_pr.registration_lock);
+
+       buf[4] = ((add_len >> 24) & 0xff);
+       buf[5] = ((add_len >> 16) & 0xff);
+       buf[6] = ((add_len >> 8) & 0xff);
+       buf[7] = (add_len & 0xff);
+
+       transport_kunmap_data_sg(cmd);
+
+       return 0;
+}
+
+/*
+ * PERSISTENT_RESERVE_IN Service Action READ_RESERVATION
+ *
+ * See spc4r17 section 5.7.6.3 and section 6.13.3.2 Table 161 and 162
+ */
+static sense_reason_t
+core_scsi3_pri_read_reservation(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct t10_pr_registration *pr_reg;
+       unsigned char *buf;
+       u64 pr_res_key;
+       u32 add_len = 16; /* Hardcoded to 16 when a reservation is held. */
+
+       if (cmd->data_length < 8) {
+               pr_err("PRIN SA READ_RESERVATIONS SCSI Data Length: %u"
+                       " too small\n", cmd->data_length);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       buf[0] = ((dev->t10_pr.pr_generation >> 24) & 0xff);
+       buf[1] = ((dev->t10_pr.pr_generation >> 16) & 0xff);
+       buf[2] = ((dev->t10_pr.pr_generation >> 8) & 0xff);
+       buf[3] = (dev->t10_pr.pr_generation & 0xff);
+
+       spin_lock(&dev->dev_reservation_lock);
+       pr_reg = dev->dev_pr_res_holder;
+       if (pr_reg) {
+               /*
+                * Set the hardcoded Additional Length
+                */
+               buf[4] = ((add_len >> 24) & 0xff);
+               buf[5] = ((add_len >> 16) & 0xff);
+               buf[6] = ((add_len >> 8) & 0xff);
+               buf[7] = (add_len & 0xff);
+
+               if (cmd->data_length < 22)
+                       goto err;
+
+               /*
+                * Set the Reservation key.
+                *
+                * From spc4r17, section 5.7.10:
+                * A persistent reservation holder has its reservation key
+                * returned in the parameter data from a PERSISTENT
+                * RESERVE IN command with READ RESERVATION service action as
+                * follows:
+                * a) For a persistent reservation of the type Write Exclusive
+                *    - All Registrants or Exclusive Access ­ All Regitrants,
+                *      the reservation key shall be set to zero; or
+                * b) For all other persistent reservation types, the
+                *    reservation key shall be set to the registered
+                *    reservation key for the I_T nexus that holds the
+                *    persistent reservation.
+                */
+               if ((pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
+                   (pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG))
+                       pr_res_key = 0;
+               else
+                       pr_res_key = pr_reg->pr_res_key;
+
+               buf[8] = ((pr_res_key >> 56) & 0xff);
+               buf[9] = ((pr_res_key >> 48) & 0xff);
+               buf[10] = ((pr_res_key >> 40) & 0xff);
+               buf[11] = ((pr_res_key >> 32) & 0xff);
+               buf[12] = ((pr_res_key >> 24) & 0xff);
+               buf[13] = ((pr_res_key >> 16) & 0xff);
+               buf[14] = ((pr_res_key >> 8) & 0xff);
+               buf[15] = (pr_res_key & 0xff);
+               /*
+                * Set the SCOPE and TYPE
+                */
+               buf[21] = (pr_reg->pr_res_scope & 0xf0) |
+                         (pr_reg->pr_res_type & 0x0f);
+       }
+
+err:
+       spin_unlock(&dev->dev_reservation_lock);
+       transport_kunmap_data_sg(cmd);
+
+       return 0;
+}
+
+/*
+ * PERSISTENT_RESERVE_IN Service Action REPORT_CAPABILITIES
+ *
+ * See spc4r17 section 6.13.4 Table 165
+ */
+static sense_reason_t
+core_scsi3_pri_report_capabilities(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       unsigned char *buf;
+       u16 add_len = 8; /* Hardcoded to 8. */
+
+       if (cmd->data_length < 6) {
+               pr_err("PRIN SA REPORT_CAPABILITIES SCSI Data Length:"
+                       " %u too small\n", cmd->data_length);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       buf[0] = ((add_len >> 8) & 0xff);
+       buf[1] = (add_len & 0xff);
+       buf[2] |= 0x10; /* CRH: Compatible Reservation Hanlding bit. */
+       buf[2] |= 0x08; /* SIP_C: Specify Initiator Ports Capable bit */
+       buf[2] |= 0x04; /* ATP_C: All Target Ports Capable bit */
+       buf[2] |= 0x01; /* PTPL_C: Persistence across Target Power Loss bit */
+       /*
+        * We are filling in the PERSISTENT RESERVATION TYPE MASK below, so
+        * set the TMV: Task Mask Valid bit.
+        */
+       buf[3] |= 0x80;
+       /*
+        * Change ALLOW COMMANDs to 0x20 or 0x40 later from Table 166
+        */
+       buf[3] |= 0x10; /* ALLOW COMMANDs field 001b */
+       /*
+        * PTPL_A: Persistence across Target Power Loss Active bit
+        */
+       if (pr_tmpl->pr_aptpl_active)
+               buf[3] |= 0x01;
+       /*
+        * Setup the PERSISTENT RESERVATION TYPE MASK from Table 167
+        */
+       buf[4] |= 0x80; /* PR_TYPE_EXCLUSIVE_ACCESS_ALLREG */
+       buf[4] |= 0x40; /* PR_TYPE_EXCLUSIVE_ACCESS_REGONLY */
+       buf[4] |= 0x20; /* PR_TYPE_WRITE_EXCLUSIVE_REGONLY */
+       buf[4] |= 0x08; /* PR_TYPE_EXCLUSIVE_ACCESS */
+       buf[4] |= 0x02; /* PR_TYPE_WRITE_EXCLUSIVE */
+       buf[5] |= 0x01; /* PR_TYPE_EXCLUSIVE_ACCESS_ALLREG */
+
+       transport_kunmap_data_sg(cmd);
+
+       return 0;
+}
+
+/*
+ * PERSISTENT_RESERVE_IN Service Action READ_FULL_STATUS
+ *
+ * See spc4r17 section 6.13.5 Table 168 and 169
+ */
+static sense_reason_t
+core_scsi3_pri_read_full_status(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_node_acl *se_nacl;
+       struct se_portal_group *se_tpg;
+       struct t10_pr_registration *pr_reg, *pr_reg_tmp;
+       struct t10_reservation *pr_tmpl = &dev->t10_pr;
+       unsigned char *buf;
+       u32 add_desc_len = 0, add_len = 0, desc_len, exp_desc_len;
+       u32 off = 8; /* off into first Full Status descriptor */
+       int format_code = 0, pr_res_type = 0, pr_res_scope = 0;
+       bool all_reg = false;
+
+       if (cmd->data_length < 8) {
+               pr_err("PRIN SA READ_FULL_STATUS SCSI Data Length: %u"
+                       " too small\n", cmd->data_length);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       buf[0] = ((dev->t10_pr.pr_generation >> 24) & 0xff);
+       buf[1] = ((dev->t10_pr.pr_generation >> 16) & 0xff);
+       buf[2] = ((dev->t10_pr.pr_generation >> 8) & 0xff);
+       buf[3] = (dev->t10_pr.pr_generation & 0xff);
+
+       spin_lock(&dev->dev_reservation_lock);
+       if (dev->dev_pr_res_holder) {
+               struct t10_pr_registration *pr_holder = dev->dev_pr_res_holder;
+
+               if (pr_holder->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG ||
+                   pr_holder->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG) {
+                       all_reg = true;
+                       pr_res_type = pr_holder->pr_res_type;
+                       pr_res_scope = pr_holder->pr_res_scope;
+               }
+       }
+       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) {
+
+               se_nacl = pr_reg->pr_reg_nacl;
+               se_tpg = pr_reg->pr_reg_nacl->se_tpg;
+               add_desc_len = 0;
+
+               atomic_inc_mb(&pr_reg->pr_res_holders);
+               spin_unlock(&pr_tmpl->registration_lock);
+               /*
+                * Determine expected length of $FABRIC_MOD specific
+                * TransportID full status descriptor..
+                */
+               exp_desc_len = se_tpg->se_tpg_tfo->tpg_get_pr_transport_id_len(
+                               se_tpg, se_nacl, pr_reg, &format_code);
+
+               if ((exp_desc_len + add_len) > cmd->data_length) {
+                       pr_warn("SPC-3 PRIN READ_FULL_STATUS ran"
+                               " out of buffer: %d\n", cmd->data_length);
+                       spin_lock(&pr_tmpl->registration_lock);
+                       atomic_dec_mb(&pr_reg->pr_res_holders);
+                       break;
+               }
+               /*
+                * Set RESERVATION KEY
+                */
+               buf[off++] = ((pr_reg->pr_res_key >> 56) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 48) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 40) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 32) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 24) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 16) & 0xff);
+               buf[off++] = ((pr_reg->pr_res_key >> 8) & 0xff);
+               buf[off++] = (pr_reg->pr_res_key & 0xff);
+               off += 4; /* Skip Over Reserved area */
+
+               /*
+                * Set ALL_TG_PT bit if PROUT SA REGISTER had this set.
+                */
+               if (pr_reg->pr_reg_all_tg_pt)
+                       buf[off] = 0x02;
+               /*
+                * The struct se_lun pointer will be present for the
+                * reservation holder for PR_HOLDER bit.
+                *
+                * Also, if this registration is the reservation
+                * holder or there is an All Registrants reservation
+                * active, fill in SCOPE and TYPE in the next byte.
+                */
+               if (pr_reg->pr_res_holder) {
+                       buf[off++] |= 0x01;
+                       buf[off++] = (pr_reg->pr_res_scope & 0xf0) |
+                                    (pr_reg->pr_res_type & 0x0f);
+               } else if (all_reg) {
+                       buf[off++] |= 0x01;
+                       buf[off++] = (pr_res_scope & 0xf0) |
+                                    (pr_res_type & 0x0f);
+               } else {
+                       off += 2;
+               }
+
+               off += 4; /* Skip over reserved area */
+               /*
+                * From spc4r17 6.3.15:
+                *
+                * If the ALL_TG_PT bit set to zero, the RELATIVE TARGET PORT
+                * IDENTIFIER field contains the relative port identifier (see
+                * 3.1.120) of the target port that is part of the I_T nexus
+                * described by this full status descriptor. If the ALL_TG_PT
+                * bit is set to one, the contents of the RELATIVE TARGET PORT
+                * IDENTIFIER field are not defined by this standard.
+                */
+               if (!pr_reg->pr_reg_all_tg_pt) {
+                       struct se_port *port = pr_reg->pr_reg_tg_pt_lun->lun_sep;
+
+                       buf[off++] = ((port->sep_rtpi >> 8) & 0xff);
+                       buf[off++] = (port->sep_rtpi & 0xff);
+               } else
+                       off += 2; /* Skip over RELATIVE TARGET PORT IDENTIFIER */
+
+               /*
+                * Now, have the $FABRIC_MOD fill in the protocol identifier
+                */
+               desc_len = se_tpg->se_tpg_tfo->tpg_get_pr_transport_id(se_tpg,
+                               se_nacl, pr_reg, &format_code, &buf[off+4]);
+
+               spin_lock(&pr_tmpl->registration_lock);
+               atomic_dec_mb(&pr_reg->pr_res_holders);
+               /*
+                * Set the ADDITIONAL DESCRIPTOR LENGTH
+                */
+               buf[off++] = ((desc_len >> 24) & 0xff);
+               buf[off++] = ((desc_len >> 16) & 0xff);
+               buf[off++] = ((desc_len >> 8) & 0xff);
+               buf[off++] = (desc_len & 0xff);
+               /*
+                * Size of full desctipor header minus TransportID
+                * containing $FABRIC_MOD specific) initiator device/port
+                * WWN information.
+                *
+                *  See spc4r17 Section 6.13.5 Table 169
+                */
+               add_desc_len = (24 + desc_len);
+
+               off += desc_len;
+               add_len += add_desc_len;
+       }
+       spin_unlock(&pr_tmpl->registration_lock);
+       /*
+        * Set ADDITIONAL_LENGTH
+        */
+       buf[4] = ((add_len >> 24) & 0xff);
+       buf[5] = ((add_len >> 16) & 0xff);
+       buf[6] = ((add_len >> 8) & 0xff);
+       buf[7] = (add_len & 0xff);
+
+       transport_kunmap_data_sg(cmd);
+
+       return 0;
+}
+
+sense_reason_t
+target_scsi3_emulate_pr_in(struct se_cmd *cmd)
+{
+       sense_reason_t ret;
+
+       /*
+        * Following spc2r20 5.5.1 Reservations overview:
+        *
+        * If a logical unit has been reserved by any RESERVE command and is
+        * still reserved by any initiator, all PERSISTENT RESERVE IN and all
+        * PERSISTENT RESERVE OUT commands shall conflict regardless of
+        * initiator or service action and shall terminate with a RESERVATION
+        * CONFLICT status.
+        */
+       if (cmd->se_dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS) {
+               pr_err("Received PERSISTENT_RESERVE CDB while legacy"
+                       " SPC-2 reservation is held, returning"
+                       " RESERVATION_CONFLICT\n");
+               return TCM_RESERVATION_CONFLICT;
+       }
+
+       switch (cmd->t_task_cdb[1] & 0x1f) {
+       case PRI_READ_KEYS:
+               ret = core_scsi3_pri_read_keys(cmd);
+               break;
+       case PRI_READ_RESERVATION:
+               ret = core_scsi3_pri_read_reservation(cmd);
+               break;
+       case PRI_REPORT_CAPABILITIES:
+               ret = core_scsi3_pri_report_capabilities(cmd);
+               break;
+       case PRI_READ_FULL_STATUS:
+               ret = core_scsi3_pri_read_full_status(cmd);
+               break;
+       default:
+               pr_err("Unknown PERSISTENT_RESERVE_IN service"
+                       " action: 0x%02x\n", cmd->t_task_cdb[1] & 0x1f);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       if (!ret)
+               target_complete_cmd(cmd, GOOD);
+       return ret;
+}
+
+sense_reason_t
+target_check_reservation(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       sense_reason_t ret;
+
+       if (!cmd->se_sess)
+               return 0;
+       if (dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE)
+               return 0;
+       if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
+               return 0;
+
+       spin_lock(&dev->dev_reservation_lock);
+       if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
+               ret = target_scsi2_reservation_check(cmd);
+       else
+               ret = target_scsi3_pr_reservation_check(cmd);
+       spin_unlock(&dev->dev_reservation_lock);
+
+       return ret;
+}