struct atio_from_isp *atio, uint16_t status, int qfull);
 static void qlt_disable_vha(struct scsi_qla_host *vha);
 static void qlt_clear_tgt_db(struct qla_tgt *tgt);
+static void qlt_send_notify_ack(struct scsi_qla_host *vha,
+       struct imm_ntfy_from_isp *ntfy,
+       uint32_t add_flags, uint16_t resp_code, int resp_code_valid,
+       uint16_t srr_flags, uint16_t srr_reject_code, uint8_t srr_explan);
 /*
  * Global Variables
  */
        struct qla_tgt *tgt = sess->tgt;
        struct scsi_qla_host *vha = sess->vha;
        struct qla_hw_data *ha = vha->hw;
+       unsigned long flags;
+       bool logout_started = false;
+       fc_port_t fcport;
+
+       ql_dbg(ql_dbg_tgt_mgt, vha, 0xf084,
+               "%s: se_sess %p / sess %p from port %8phC loop_id %#04x"
+               " s_id %02x:%02x:%02x logout %d keep %d plogi %d\n",
+               __func__, sess->se_sess, sess, sess->port_name, sess->loop_id,
+               sess->s_id.b.domain, sess->s_id.b.area, sess->s_id.b.al_pa,
+               sess->logout_on_delete, sess->keep_nport_handle,
+               sess->plogi_ack_needed);
 
        BUG_ON(!tgt);
+
+       if (sess->logout_on_delete) {
+               int rc;
+
+               memset(&fcport, 0, sizeof(fcport));
+               fcport.loop_id = sess->loop_id;
+               fcport.d_id = sess->s_id;
+               memcpy(fcport.port_name, sess->port_name, WWN_SIZE);
+               fcport.vha = vha;
+               fcport.tgt_session = sess;
+
+               rc = qla2x00_post_async_logout_work(vha, &fcport, NULL);
+               if (rc != QLA_SUCCESS)
+                       ql_log(ql_log_warn, vha, 0xf085,
+                              "Schedule logo failed sess %p rc %d\n",
+                              sess, rc);
+               else
+                       logout_started = true;
+       }
+
        /*
         * Release the target session for FC Nexus from fabric module code.
         */
        if (sess->se_sess != NULL)
                ha->tgt.tgt_ops->free_session(sess);
 
+       if (logout_started) {
+               bool traced = false;
+
+               while (!ACCESS_ONCE(sess->logout_completed)) {
+                       if (!traced) {
+                               ql_dbg(ql_dbg_tgt_mgt, vha, 0xf086,
+                                       "%s: waiting for sess %p logout\n",
+                                       __func__, sess);
+                               traced = true;
+                       }
+                       msleep(100);
+               }
+
+               ql_dbg(ql_dbg_tgt_mgt, vha, 0xf087,
+                       "%s: sess %p logout completed\n",
+                       __func__, sess);
+       }
+
+       spin_lock_irqsave(&ha->hardware_lock, flags);
+
+       if (sess->plogi_ack_needed)
+               qlt_send_notify_ack(vha, &sess->tm_iocb,
+                                   0, 0, 0, 0, 0, 0);
+
+       list_del(&sess->sess_list_entry);
+
+       spin_unlock_irqrestore(&ha->hardware_lock, flags);
+
        ql_dbg(ql_dbg_tgt_mgt, vha, 0xf001,
            "Unregistration of sess %p finished\n", sess);
 
 
        vha->hw->tgt.tgt_ops->clear_nacl_from_fcport_map(sess);
 
-       list_del(&sess->sess_list_entry);
-       if (sess->deleted)
-               list_del(&sess->del_list_entry);
+       if (!list_empty(&sess->del_list_entry))
+               list_del_init(&sess->del_list_entry);
+       sess->deleted = QLA_SESS_DELETION_IN_PROGRESS;
 
        INIT_WORK(&sess->free_work, qlt_free_session_done);
        schedule_work(&sess->free_work);
        struct qla_tgt *tgt = sess->tgt;
        uint32_t dev_loss_tmo = tgt->ha->port_down_retry_count + 5;
 
-       if (sess->deleted)
-               return;
+       if (sess->deleted) {
+               /* Upgrade to unconditional deletion in case it was temporary */
+               if (immediate && sess->deleted == QLA_SESS_DELETION_PENDING)
+                       list_del(&sess->del_list_entry);
+               else
+                       return;
+       }
 
        ql_dbg(ql_dbg_tgt, sess->vha, 0xe001,
            "Scheduling sess %p for deletion\n", sess);
-       list_add_tail(&sess->del_list_entry, &tgt->del_sess_list);
-       sess->deleted = 1;
 
-       if (immediate)
+       if (immediate) {
                dev_loss_tmo = 0;
+               sess->deleted = QLA_SESS_DELETION_IN_PROGRESS;
+               list_add(&sess->del_list_entry, &tgt->del_sess_list);
+       } else {
+               sess->deleted = QLA_SESS_DELETION_PENDING;
+               list_add_tail(&sess->del_list_entry, &tgt->del_sess_list);
+       }
 
        sess->expires = jiffies + dev_loss_tmo * HZ;
 
        ql_dbg(ql_dbg_tgt, sess->vha, 0xe048,
            "qla_target(%d): session for port %8phC (loop ID %d) scheduled for "
-           "deletion in %u secs (expires: %lu) immed: %d\n",
+           "deletion in %u secs (expires: %lu) immed: %d, logout: %d\n",
            sess->vha->vp_idx, sess->port_name, sess->loop_id, dev_loss_tmo,
-           sess->expires, immediate);
+           sess->expires, immediate, sess->logout_on_delete);
 
        if (immediate)
-               schedule_delayed_work(&tgt->sess_del_work, 0);
+               mod_delayed_work(system_wq, &tgt->sess_del_work, 0);
        else
                schedule_delayed_work(&tgt->sess_del_work,
                    sess->expires - jiffies);
 /* ha->hardware_lock supposed to be held on entry */
 static void qlt_undelete_sess(struct qla_tgt_sess *sess)
 {
-       BUG_ON(!sess->deleted);
+       BUG_ON(sess->deleted != QLA_SESS_DELETION_PENDING);
 
-       list_del(&sess->del_list_entry);
+       list_del_init(&sess->del_list_entry);
        sess->deleted = 0;
 }
 
                    del_list_entry);
                elapsed = jiffies;
                if (time_after_eq(elapsed, sess->expires)) {
-                       qlt_undelete_sess(sess);
+                       /* No turning back */
+                       list_del_init(&sess->del_list_entry);
+                       sess->deleted = QLA_SESS_DELETION_IN_PROGRESS;
 
                        ql_dbg(ql_dbg_tgt_mgt, vha, 0xf004,
                            "Timeout: sess %p about to be deleted\n",
                            fcport->d_id.b.al_pa, fcport->d_id.b.area,
                            fcport->loop_id);
 
+                       /* Cannot undelete at this point */
+                       if (sess->deleted == QLA_SESS_DELETION_IN_PROGRESS) {
+                               spin_unlock_irqrestore(&ha->hardware_lock,
+                                   flags);
+                               return NULL;
+                       }
+
                        if (sess->deleted)
                                qlt_undelete_sess(sess);
 
        sess->s_id = fcport->d_id;
        sess->loop_id = fcport->loop_id;
        sess->local = local;
+       INIT_LIST_HEAD(&sess->del_list_entry);
+
+       /* Under normal circumstances we want to logout from firmware when
+        * session eventually ends and release corresponding nport handle.
+        * In the exception cases (e.g. when new PLOGI is waiting) corresponding
+        * code will adjust these flags as necessary. */
+       sess->logout_on_delete = 1;
+       sess->keep_nport_handle = 0;
 
        ql_dbg(ql_dbg_tgt_mgt, vha, 0xf006,
            "Adding sess %p to tgt %p via ->check_initiator_node_acl()\n",
                mutex_unlock(&vha->vha_tgt.tgt_mutex);
 
                spin_lock_irqsave(&ha->hardware_lock, flags);
+       } else if (sess->deleted == QLA_SESS_DELETION_IN_PROGRESS) {
+               /* Point of no return */
+               spin_unlock_irqrestore(&ha->hardware_lock, flags);
+               return;
        } else {
                kref_get(&sess->se_sess->sess_kref);
 
        unsigned long flags = 0;
        int res;
 
+       spin_lock_irqsave(&ha->hardware_lock, flags);
+       if (cmd->sess && cmd->sess->deleted == QLA_SESS_DELETION_IN_PROGRESS) {
+               cmd->state = QLA_TGT_STATE_PROCESSED;
+               if (cmd->sess->logout_completed)
+                       /* no need to terminate. FW already freed exchange. */
+                       qlt_abort_cmd_on_host_reset(cmd->vha, cmd);
+               else
+                       qlt_send_term_exchange(vha, cmd, &cmd->atio, 1);
+               spin_unlock_irqrestore(&ha->hardware_lock, flags);
+               return 0;
+       }
+       spin_unlock_irqrestore(&ha->hardware_lock, flags);
+
        memset(&prm, 0, sizeof(prm));
        qlt_check_srr_debug(cmd, &xmit_type);
 
 
        spin_lock_irqsave(&ha->hardware_lock, flags);
 
-       if (qla2x00_reset_active(vha) || cmd->reset_count != ha->chip_reset) {
+       if (qla2x00_reset_active(vha) || (cmd->reset_count != ha->chip_reset) ||
+           (cmd->sess && cmd->sess->deleted == QLA_SESS_DELETION_IN_PROGRESS)) {
                /*
                 * Either a chip reset is active or this request was from
                 * previous life, just abort the processing.
 }
 
 
+/* If hardware_lock held on entry, might drop it, then reaquire */
+/* This function sends the appropriate CTIO to ISP 2xxx or 24xx */
+static int __qlt_send_term_imm_notif(struct scsi_qla_host *vha,
+       struct imm_ntfy_from_isp *ntfy)
+{
+       struct nack_to_isp *nack;
+       struct qla_hw_data *ha = vha->hw;
+       request_t *pkt;
+       int ret = 0;
+
+       ql_dbg(ql_dbg_tgt_tmr, vha, 0xe01c,
+           "Sending TERM ELS CTIO (ha=%p)\n", ha);
+
+       pkt = (request_t *)qla2x00_alloc_iocbs_ready(vha, NULL);
+       if (pkt == NULL) {
+               ql_dbg(ql_dbg_tgt, vha, 0xe080,
+                   "qla_target(%d): %s failed: unable to allocate "
+                   "request packet\n", vha->vp_idx, __func__);
+               return -ENOMEM;
+       }
+
+       pkt->entry_type = NOTIFY_ACK_TYPE;
+       pkt->entry_count = 1;
+       pkt->handle = QLA_TGT_SKIP_HANDLE | CTIO_COMPLETION_HANDLE_MARK;
+
+       nack = (struct nack_to_isp *)pkt;
+       nack->ox_id = ntfy->ox_id;
+
+       nack->u.isp24.nport_handle = ntfy->u.isp24.nport_handle;
+       if (le16_to_cpu(ntfy->u.isp24.status) == IMM_NTFY_ELS) {
+               nack->u.isp24.flags = ntfy->u.isp24.flags &
+                       __constant_cpu_to_le32(NOTIFY24XX_FLAGS_PUREX_IOCB);
+       }
+
+       /* terminate */
+       nack->u.isp24.flags |=
+               __constant_cpu_to_le16(NOTIFY_ACK_FLAGS_TERMINATE);
+
+       nack->u.isp24.srr_rx_id = ntfy->u.isp24.srr_rx_id;
+       nack->u.isp24.status = ntfy->u.isp24.status;
+       nack->u.isp24.status_subcode = ntfy->u.isp24.status_subcode;
+       nack->u.isp24.fw_handle = ntfy->u.isp24.fw_handle;
+       nack->u.isp24.exchange_address = ntfy->u.isp24.exchange_address;
+       nack->u.isp24.srr_rel_offs = ntfy->u.isp24.srr_rel_offs;
+       nack->u.isp24.srr_ui = ntfy->u.isp24.srr_ui;
+       nack->u.isp24.vp_index = ntfy->u.isp24.vp_index;
+
+       qla2x00_start_iocbs(vha, vha->req);
+       return ret;
+}
+
+static void qlt_send_term_imm_notif(struct scsi_qla_host *vha,
+       struct imm_ntfy_from_isp *imm, int ha_locked)
+{
+       unsigned long flags = 0;
+       int rc;
+
+       if (qlt_issue_marker(vha, ha_locked) < 0)
+               return;
+
+       if (ha_locked) {
+               rc = __qlt_send_term_imm_notif(vha, imm);
+
+#if 0  /* Todo  */
+               if (rc == -ENOMEM)
+                       qlt_alloc_qfull_cmd(vha, imm, 0, 0);
+#endif
+               goto done;
+       }
+
+       spin_lock_irqsave(&vha->hw->hardware_lock, flags);
+       rc = __qlt_send_term_imm_notif(vha, imm);
+
+#if 0  /* Todo */
+       if (rc == -ENOMEM)
+               qlt_alloc_qfull_cmd(vha, imm, 0, 0);
+#endif
+
+done:
+       if (!ha_locked)
+               spin_unlock_irqrestore(&vha->hw->hardware_lock, flags);
+}
+
 /* If hardware_lock held on entry, might drop it, then reaquire */
 /* This function sends the appropriate CTIO to ISP 2xxx or 24xx */
 static int __qlt_send_term_exchange(struct scsi_qla_host *vha,
        return __qlt_abort_task(vha, iocb, sess);
 }
 
+void qlt_logo_completion_handler(fc_port_t *fcport, int rc)
+{
+       if (fcport->tgt_session) {
+               if (rc != MBS_COMMAND_COMPLETE) {
+                       ql_dbg(ql_dbg_tgt_mgt, fcport->vha, 0xf088,
+                               "%s: se_sess %p / sess %p from"
+                               " port %8phC loop_id %#04x s_id %02x:%02x:%02x"
+                               " LOGO failed: %#x\n",
+                               __func__,
+                               fcport->tgt_session->se_sess,
+                               fcport->tgt_session,
+                               fcport->port_name, fcport->loop_id,
+                               fcport->d_id.b.domain, fcport->d_id.b.area,
+                               fcport->d_id.b.al_pa, rc);
+               }
+
+               fcport->tgt_session->logout_completed = 1;
+       }
+}
+
+static void qlt_swap_imm_ntfy_iocb(struct imm_ntfy_from_isp *a,
+    struct imm_ntfy_from_isp *b)
+{
+       struct imm_ntfy_from_isp tmp;
+       memcpy(&tmp, a, sizeof(struct imm_ntfy_from_isp));
+       memcpy(a, b, sizeof(struct imm_ntfy_from_isp));
+       memcpy(b, &tmp, sizeof(struct imm_ntfy_from_isp));
+}
+
+/*
+* ha->hardware_lock supposed to be held on entry (to protect tgt->sess_list)
+*
+* Schedules sessions with matching port_id/loop_id but different wwn for
+* deletion. Returns existing session with matching wwn if present.
+* Null otherwise.
+*/
+static struct qla_tgt_sess *
+qlt_find_sess_invalidate_other(struct qla_tgt *tgt, uint64_t wwn,
+    port_id_t port_id, uint16_t loop_id)
+{
+       struct qla_tgt_sess *sess = NULL, *other_sess;
+       uint64_t other_wwn;
+
+       list_for_each_entry(other_sess, &tgt->sess_list, sess_list_entry) {
+
+               other_wwn = wwn_to_u64(other_sess->port_name);
+
+               if (wwn == other_wwn) {
+                       WARN_ON(sess);
+                       sess = other_sess;
+                       continue;
+               }
+
+               /* find other sess with nport_id collision */
+               if (port_id.b24 == other_sess->s_id.b24) {
+                       if (loop_id != other_sess->loop_id) {
+                               ql_dbg(ql_dbg_tgt_tmr, tgt->vha, 0x1000c,
+                                   "Invalidating sess %p loop_id %d wwn %llx.\n",
+                                   other_sess, other_sess->loop_id, other_wwn);
+
+                               /*
+                                * logout_on_delete is set by default, but another
+                                * session that has the same s_id/loop_id combo
+                                * might have cleared it when requested this session
+                                * deletion, so don't touch it
+                                */
+                               qlt_schedule_sess_for_deletion(other_sess, true);
+                       } else {
+                               /*
+                                * Another wwn used to have our s_id/loop_id
+                                * combo - kill the session, but don't log out
+                                */
+                               sess->logout_on_delete = 0;
+                               qlt_schedule_sess_for_deletion(other_sess,
+                                   true);
+                       }
+                       continue;
+               }
+
+               /* find other sess with nport handle collision */
+               if (loop_id == other_sess->loop_id) {
+                       ql_dbg(ql_dbg_tgt_tmr, tgt->vha, 0x1000d,
+                              "Invalidating sess %p loop_id %d wwn %llx.\n",
+                              other_sess, other_sess->loop_id, other_wwn);
+
+                       /* Same loop_id but different s_id
+                        * Ok to kill and logout */
+                       qlt_schedule_sess_for_deletion(other_sess, true);
+               }
+       }
+
+       return sess;
+}
+
 /*
  * ha->hardware_lock supposed to be held on entry. Might drop it, then reaquire
  */
 static int qlt_24xx_handle_els(struct scsi_qla_host *vha,
        struct imm_ntfy_from_isp *iocb)
 {
+       struct qla_tgt *tgt = vha->vha_tgt.qla_tgt;
+       struct qla_tgt_sess *sess = NULL;
+       uint64_t wwn;
+       port_id_t port_id;
+       uint16_t loop_id;
+       uint16_t wd3_lo;
        int res = 0;
 
+       wwn = wwn_to_u64(iocb->u.isp24.port_name);
+
+       port_id.b.domain = iocb->u.isp24.port_id[2];
+       port_id.b.area   = iocb->u.isp24.port_id[1];
+       port_id.b.al_pa  = iocb->u.isp24.port_id[0];
+       port_id.b.rsvd_1 = 0;
+
+       loop_id = le16_to_cpu(iocb->u.isp24.nport_handle);
+
        ql_dbg(ql_dbg_tgt_mgt, vha, 0xf026,
            "qla_target(%d): Port ID: 0x%3phC ELS opcode: 0x%02x\n",
            vha->vp_idx, iocb->u.isp24.port_id, iocb->u.isp24.status_subcode);
 
+       /* res = 1 means ack at the end of thread
+        * res = 0 means ack async/later.
+        */
        switch (iocb->u.isp24.status_subcode) {
        case ELS_PLOGI:
-       case ELS_FLOGI:
+
+               if (wwn)
+                       sess = qlt_find_sess_invalidate_other(tgt, wwn,
+                           port_id, loop_id);
+
+               if (!sess || IS_SW_RESV_ADDR(sess->s_id)) {
+                       res = 1;
+                       break;
+               }
+
+               if (sess->plogi_ack_needed) {
+                       /*
+                        * Initiator sent another PLOGI before last PLOGI could
+                        * finish. Swap plogi iocbs and terminate old one
+                        * without acking, new one will get acked when session
+                        * deletion completes.
+                        */
+                       ql_log(ql_log_warn, sess->vha, 0xf089,
+                           "sess %p received double plogi.\n", sess);
+
+                       qlt_swap_imm_ntfy_iocb(iocb, &sess->tm_iocb);
+
+                       qlt_send_term_imm_notif(vha, iocb, 1);
+
+                       res = 0;
+                       break;
+               }
+
+               res = 0;
+
+               /*
+                * Save immediate Notif IOCB for Ack when sess is done
+                * and being deleted.
+                */
+               memcpy(&sess->tm_iocb, iocb, sizeof(sess->tm_iocb));
+               sess->plogi_ack_needed  = 1;
+
+                /*
+                 * Under normal circumstances we want to release nport handle
+                 * during LOGO process to avoid nport handle leaks inside FW.
+                 * The exception is when LOGO is done while another PLOGI with
+                 * the same nport handle is waiting as might be the case here.
+                 * Note: there is always a possibily of a race where session
+                 * deletion has already started for other reasons (e.g. ACL
+                 * removal) and now PLOGI arrives:
+                 * 1. if PLOGI arrived in FW after nport handle has been freed,
+                 *    FW must have assigned this PLOGI a new/same handle and we
+                 *    can proceed ACK'ing it as usual when session deletion
+                 *    completes.
+                 * 2. if PLOGI arrived in FW before LOGO with LCF_FREE_NPORT
+                 *    bit reached it, the handle has now been released. We'll
+                 *    get an error when we ACK this PLOGI. Nothing will be sent
+                 *    back to initiator. Initiator should eventually retry
+                 *    PLOGI and situation will correct itself.
+                 */
+               sess->keep_nport_handle = ((sess->loop_id == loop_id) &&
+                                          (sess->s_id.b24 == port_id.b24));
+               qlt_schedule_sess_for_deletion(sess, true);
+               break;
+
        case ELS_PRLI:
+               wd3_lo = le16_to_cpu(iocb->u.isp24.u.prli.wd3_lo);
+
+               if (wwn)
+                       sess = qlt_find_sess_invalidate_other(tgt, wwn, port_id,
+                           loop_id);
+
+               if (sess != NULL) {
+                       if (sess->deleted) {
+                               /*
+                                * Impatient initiator sent PRLI before last
+                                * PLOGI could finish. Will force him to re-try,
+                                * while last one finishes.
+                                */
+                               ql_log(ql_log_warn, sess->vha, 0xf090,
+                                   "sess %p PRLI received, before plogi ack.\n",
+                                   sess);
+                               qlt_send_term_imm_notif(vha, iocb, 1);
+                               res = 0;
+                               break;
+                       }
+
+                       /*
+                        * This shouldn't happen under normal circumstances,
+                        * since we have deleted the old session during PLOGI
+                        */
+                       ql_dbg(ql_dbg_tgt_mgt, vha, 0xf091,
+                           "PRLI (loop_id %#04x) for existing sess %p (loop_id %#04x)\n",
+                           sess->loop_id, sess, iocb->u.isp24.nport_handle);
+
+                       sess->local = 0;
+                       sess->loop_id = loop_id;
+                       sess->s_id = port_id;
+
+                       if (wd3_lo & BIT_7)
+                               sess->conf_compl_supported = 1;
+
+                       res = 1;
+               } else {
+                       /* todo: else - create sess here. */
+                       res = 1; /* send notify ack */
+               }
+
+               break;
+
        case ELS_LOGO:
        case ELS_PRLO:
                res = qlt_reset(vha, iocb, QLA_TGT_NEXUS_LOSS_SESS);
                break;
        }
 
+       case ELS_FLOGI: /* should never happen */
        default:
                ql_dbg(ql_dbg_tgt_mgt, vha, 0xf061,
                    "qla_target(%d): Unsupported ELS command %x "