diff --git a/sys/dev/nvme/nvme_qpair.c b/sys/dev/nvme/nvme_qpair.c
index 6ee5fa9d4c30..827054efd48e 100644
--- a/sys/dev/nvme/nvme_qpair.c
+++ b/sys/dev/nvme/nvme_qpair.c
@@ -1,1365 +1,1380 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (C) 2012-2014 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/bus.h>
 #include <sys/conf.h>
 #include <sys/domainset.h>
 #include <sys/proc.h>
 
 #include <dev/pci/pcivar.h>
 
 #include "nvme_private.h"
 
 typedef enum error_print { ERROR_PRINT_NONE, ERROR_PRINT_NO_RETRY, ERROR_PRINT_ALL } error_print_t;
 #define DO_NOT_RETRY	1
 
 static void	_nvme_qpair_submit_request(struct nvme_qpair *qpair,
 					   struct nvme_request *req);
 static void	nvme_qpair_destroy(struct nvme_qpair *qpair);
 
 struct nvme_opcode_string {
 	uint16_t	opc;
 	const char *	str;
 };
 
 static struct nvme_opcode_string admin_opcode[] = {
 	{ NVME_OPC_DELETE_IO_SQ, "DELETE IO SQ" },
 	{ NVME_OPC_CREATE_IO_SQ, "CREATE IO SQ" },
 	{ NVME_OPC_GET_LOG_PAGE, "GET LOG PAGE" },
 	{ NVME_OPC_DELETE_IO_CQ, "DELETE IO CQ" },
 	{ NVME_OPC_CREATE_IO_CQ, "CREATE IO CQ" },
 	{ NVME_OPC_IDENTIFY, "IDENTIFY" },
 	{ NVME_OPC_ABORT, "ABORT" },
 	{ NVME_OPC_SET_FEATURES, "SET FEATURES" },
 	{ NVME_OPC_GET_FEATURES, "GET FEATURES" },
 	{ NVME_OPC_ASYNC_EVENT_REQUEST, "ASYNC EVENT REQUEST" },
 	{ NVME_OPC_FIRMWARE_ACTIVATE, "FIRMWARE ACTIVATE" },
 	{ NVME_OPC_FIRMWARE_IMAGE_DOWNLOAD, "FIRMWARE IMAGE DOWNLOAD" },
 	{ NVME_OPC_DEVICE_SELF_TEST, "DEVICE SELF-TEST" },
 	{ NVME_OPC_NAMESPACE_ATTACHMENT, "NAMESPACE ATTACHMENT" },
 	{ NVME_OPC_KEEP_ALIVE, "KEEP ALIVE" },
 	{ NVME_OPC_DIRECTIVE_SEND, "DIRECTIVE SEND" },
 	{ NVME_OPC_DIRECTIVE_RECEIVE, "DIRECTIVE RECEIVE" },
 	{ NVME_OPC_VIRTUALIZATION_MANAGEMENT, "VIRTUALIZATION MANAGEMENT" },
 	{ NVME_OPC_NVME_MI_SEND, "NVME-MI SEND" },
 	{ NVME_OPC_NVME_MI_RECEIVE, "NVME-MI RECEIVE" },
 	{ NVME_OPC_DOORBELL_BUFFER_CONFIG, "DOORBELL BUFFER CONFIG" },
 	{ NVME_OPC_FORMAT_NVM, "FORMAT NVM" },
 	{ NVME_OPC_SECURITY_SEND, "SECURITY SEND" },
 	{ NVME_OPC_SECURITY_RECEIVE, "SECURITY RECEIVE" },
 	{ NVME_OPC_SANITIZE, "SANITIZE" },
 	{ NVME_OPC_GET_LBA_STATUS, "GET LBA STATUS" },
 	{ 0xFFFF, "ADMIN COMMAND" }
 };
 
 static struct nvme_opcode_string io_opcode[] = {
 	{ NVME_OPC_FLUSH, "FLUSH" },
 	{ NVME_OPC_WRITE, "WRITE" },
 	{ NVME_OPC_READ, "READ" },
 	{ NVME_OPC_WRITE_UNCORRECTABLE, "WRITE UNCORRECTABLE" },
 	{ NVME_OPC_COMPARE, "COMPARE" },
 	{ NVME_OPC_WRITE_ZEROES, "WRITE ZEROES" },
 	{ NVME_OPC_DATASET_MANAGEMENT, "DATASET MANAGEMENT" },
 	{ NVME_OPC_VERIFY, "VERIFY" },
 	{ NVME_OPC_RESERVATION_REGISTER, "RESERVATION REGISTER" },
 	{ NVME_OPC_RESERVATION_REPORT, "RESERVATION REPORT" },
 	{ NVME_OPC_RESERVATION_ACQUIRE, "RESERVATION ACQUIRE" },
 	{ NVME_OPC_RESERVATION_RELEASE, "RESERVATION RELEASE" },
 	{ 0xFFFF, "IO COMMAND" }
 };
 
 static const char *
 get_admin_opcode_string(uint16_t opc)
 {
 	struct nvme_opcode_string *entry;
 
 	entry = admin_opcode;
 
 	while (entry->opc != 0xFFFF) {
 		if (entry->opc == opc)
 			return (entry->str);
 		entry++;
 	}
 	return (entry->str);
 }
 
 static const char *
 get_io_opcode_string(uint16_t opc)
 {
 	struct nvme_opcode_string *entry;
 
 	entry = io_opcode;
 
 	while (entry->opc != 0xFFFF) {
 		if (entry->opc == opc)
 			return (entry->str);
 		entry++;
 	}
 	return (entry->str);
 }
 
 static void
 nvme_admin_qpair_print_command(struct nvme_qpair *qpair,
     struct nvme_command *cmd)
 {
 
 	nvme_printf(qpair->ctrlr, "%s (%02x) sqid:%d cid:%d nsid:%x "
 	    "cdw10:%08x cdw11:%08x\n",
 	    get_admin_opcode_string(cmd->opc), cmd->opc, qpair->id, cmd->cid,
 	    le32toh(cmd->nsid), le32toh(cmd->cdw10), le32toh(cmd->cdw11));
 }
 
 static void
 nvme_io_qpair_print_command(struct nvme_qpair *qpair,
     struct nvme_command *cmd)
 {
 
 	switch (cmd->opc) {
 	case NVME_OPC_WRITE:
 	case NVME_OPC_READ:
 	case NVME_OPC_WRITE_UNCORRECTABLE:
 	case NVME_OPC_COMPARE:
 	case NVME_OPC_WRITE_ZEROES:
 	case NVME_OPC_VERIFY:
 		nvme_printf(qpair->ctrlr, "%s sqid:%d cid:%d nsid:%d "
 		    "lba:%llu len:%d\n",
 		    get_io_opcode_string(cmd->opc), qpair->id, cmd->cid, le32toh(cmd->nsid),
 		    ((unsigned long long)le32toh(cmd->cdw11) << 32) + le32toh(cmd->cdw10),
 		    (le32toh(cmd->cdw12) & 0xFFFF) + 1);
 		break;
 	case NVME_OPC_FLUSH:
 	case NVME_OPC_DATASET_MANAGEMENT:
 	case NVME_OPC_RESERVATION_REGISTER:
 	case NVME_OPC_RESERVATION_REPORT:
 	case NVME_OPC_RESERVATION_ACQUIRE:
 	case NVME_OPC_RESERVATION_RELEASE:
 		nvme_printf(qpair->ctrlr, "%s sqid:%d cid:%d nsid:%d\n",
 		    get_io_opcode_string(cmd->opc), qpair->id, cmd->cid, le32toh(cmd->nsid));
 		break;
 	default:
 		nvme_printf(qpair->ctrlr, "%s (%02x) sqid:%d cid:%d nsid:%d\n",
 		    get_io_opcode_string(cmd->opc), cmd->opc, qpair->id,
 		    cmd->cid, le32toh(cmd->nsid));
 		break;
 	}
 }
 
 static void
 nvme_qpair_print_command(struct nvme_qpair *qpair, struct nvme_command *cmd)
 {
 	if (qpair->id == 0)
 		nvme_admin_qpair_print_command(qpair, cmd);
 	else
 		nvme_io_qpair_print_command(qpair, cmd);
 	if (nvme_verbose_cmd_dump) {
 		nvme_printf(qpair->ctrlr,
 		    "nsid:%#x rsvd2:%#x rsvd3:%#x mptr:%#jx prp1:%#jx prp2:%#jx\n",
 		    cmd->nsid, cmd->rsvd2, cmd->rsvd3, (uintmax_t)cmd->mptr,
 		    (uintmax_t)cmd->prp1, (uintmax_t)cmd->prp2);
 		nvme_printf(qpair->ctrlr,
 		    "cdw10: %#x cdw11:%#x cdw12:%#x cdw13:%#x cdw14:%#x cdw15:%#x\n",
 		    cmd->cdw10, cmd->cdw11, cmd->cdw12, cmd->cdw13, cmd->cdw14,
 		    cmd->cdw15);
 	}
 }
 
 struct nvme_status_string {
 	uint16_t	sc;
 	const char *	str;
 };
 
 static struct nvme_status_string generic_status[] = {
 	{ NVME_SC_SUCCESS, "SUCCESS" },
 	{ NVME_SC_INVALID_OPCODE, "INVALID OPCODE" },
 	{ NVME_SC_INVALID_FIELD, "INVALID_FIELD" },
 	{ NVME_SC_COMMAND_ID_CONFLICT, "COMMAND ID CONFLICT" },
 	{ NVME_SC_DATA_TRANSFER_ERROR, "DATA TRANSFER ERROR" },
 	{ NVME_SC_ABORTED_POWER_LOSS, "ABORTED - POWER LOSS" },
 	{ NVME_SC_INTERNAL_DEVICE_ERROR, "INTERNAL DEVICE ERROR" },
 	{ NVME_SC_ABORTED_BY_REQUEST, "ABORTED - BY REQUEST" },
 	{ NVME_SC_ABORTED_SQ_DELETION, "ABORTED - SQ DELETION" },
 	{ NVME_SC_ABORTED_FAILED_FUSED, "ABORTED - FAILED FUSED" },
 	{ NVME_SC_ABORTED_MISSING_FUSED, "ABORTED - MISSING FUSED" },
 	{ NVME_SC_INVALID_NAMESPACE_OR_FORMAT, "INVALID NAMESPACE OR FORMAT" },
 	{ NVME_SC_COMMAND_SEQUENCE_ERROR, "COMMAND SEQUENCE ERROR" },
 	{ NVME_SC_INVALID_SGL_SEGMENT_DESCR, "INVALID SGL SEGMENT DESCRIPTOR" },
 	{ NVME_SC_INVALID_NUMBER_OF_SGL_DESCR, "INVALID NUMBER OF SGL DESCRIPTORS" },
 	{ NVME_SC_DATA_SGL_LENGTH_INVALID, "DATA SGL LENGTH INVALID" },
 	{ NVME_SC_METADATA_SGL_LENGTH_INVALID, "METADATA SGL LENGTH INVALID" },
 	{ NVME_SC_SGL_DESCRIPTOR_TYPE_INVALID, "SGL DESCRIPTOR TYPE INVALID" },
 	{ NVME_SC_INVALID_USE_OF_CMB, "INVALID USE OF CONTROLLER MEMORY BUFFER" },
 	{ NVME_SC_PRP_OFFET_INVALID, "PRP OFFET INVALID" },
 	{ NVME_SC_ATOMIC_WRITE_UNIT_EXCEEDED, "ATOMIC WRITE UNIT EXCEEDED" },
 	{ NVME_SC_OPERATION_DENIED, "OPERATION DENIED" },
 	{ NVME_SC_SGL_OFFSET_INVALID, "SGL OFFSET INVALID" },
 	{ NVME_SC_HOST_ID_INCONSISTENT_FORMAT, "HOST IDENTIFIER INCONSISTENT FORMAT" },
 	{ NVME_SC_KEEP_ALIVE_TIMEOUT_EXPIRED, "KEEP ALIVE TIMEOUT EXPIRED" },
 	{ NVME_SC_KEEP_ALIVE_TIMEOUT_INVALID, "KEEP ALIVE TIMEOUT INVALID" },
 	{ NVME_SC_ABORTED_DUE_TO_PREEMPT, "COMMAND ABORTED DUE TO PREEMPT AND ABORT" },
 	{ NVME_SC_SANITIZE_FAILED, "SANITIZE FAILED" },
 	{ NVME_SC_SANITIZE_IN_PROGRESS, "SANITIZE IN PROGRESS" },
 	{ NVME_SC_SGL_DATA_BLOCK_GRAN_INVALID, "SGL_DATA_BLOCK_GRANULARITY_INVALID" },
 	{ NVME_SC_NOT_SUPPORTED_IN_CMB, "COMMAND NOT SUPPORTED FOR QUEUE IN CMB" },
 	{ NVME_SC_NAMESPACE_IS_WRITE_PROTECTED, "NAMESPACE IS WRITE PROTECTED" },
 	{ NVME_SC_COMMAND_INTERRUPTED, "COMMAND INTERRUPTED" },
 	{ NVME_SC_TRANSIENT_TRANSPORT_ERROR, "TRANSIENT TRANSPORT ERROR" },
 
 	{ NVME_SC_LBA_OUT_OF_RANGE, "LBA OUT OF RANGE" },
 	{ NVME_SC_CAPACITY_EXCEEDED, "CAPACITY EXCEEDED" },
 	{ NVME_SC_NAMESPACE_NOT_READY, "NAMESPACE NOT READY" },
 	{ NVME_SC_RESERVATION_CONFLICT, "RESERVATION CONFLICT" },
 	{ NVME_SC_FORMAT_IN_PROGRESS, "FORMAT IN PROGRESS" },
 	{ 0xFFFF, "GENERIC" }
 };
 
 static struct nvme_status_string command_specific_status[] = {
 	{ NVME_SC_COMPLETION_QUEUE_INVALID, "INVALID COMPLETION QUEUE" },
 	{ NVME_SC_INVALID_QUEUE_IDENTIFIER, "INVALID QUEUE IDENTIFIER" },
 	{ NVME_SC_MAXIMUM_QUEUE_SIZE_EXCEEDED, "MAX QUEUE SIZE EXCEEDED" },
 	{ NVME_SC_ABORT_COMMAND_LIMIT_EXCEEDED, "ABORT CMD LIMIT EXCEEDED" },
 	{ NVME_SC_ASYNC_EVENT_REQUEST_LIMIT_EXCEEDED, "ASYNC LIMIT EXCEEDED" },
 	{ NVME_SC_INVALID_FIRMWARE_SLOT, "INVALID FIRMWARE SLOT" },
 	{ NVME_SC_INVALID_FIRMWARE_IMAGE, "INVALID FIRMWARE IMAGE" },
 	{ NVME_SC_INVALID_INTERRUPT_VECTOR, "INVALID INTERRUPT VECTOR" },
 	{ NVME_SC_INVALID_LOG_PAGE, "INVALID LOG PAGE" },
 	{ NVME_SC_INVALID_FORMAT, "INVALID FORMAT" },
 	{ NVME_SC_FIRMWARE_REQUIRES_RESET, "FIRMWARE REQUIRES RESET" },
 	{ NVME_SC_INVALID_QUEUE_DELETION, "INVALID QUEUE DELETION" },
 	{ NVME_SC_FEATURE_NOT_SAVEABLE, "FEATURE IDENTIFIER NOT SAVEABLE" },
 	{ NVME_SC_FEATURE_NOT_CHANGEABLE, "FEATURE NOT CHANGEABLE" },
 	{ NVME_SC_FEATURE_NOT_NS_SPECIFIC, "FEATURE NOT NAMESPACE SPECIFIC" },
 	{ NVME_SC_FW_ACT_REQUIRES_NVMS_RESET, "FIRMWARE ACTIVATION REQUIRES NVM SUBSYSTEM RESET" },
 	{ NVME_SC_FW_ACT_REQUIRES_RESET, "FIRMWARE ACTIVATION REQUIRES RESET" },
 	{ NVME_SC_FW_ACT_REQUIRES_TIME, "FIRMWARE ACTIVATION REQUIRES MAXIMUM TIME VIOLATION" },
 	{ NVME_SC_FW_ACT_PROHIBITED, "FIRMWARE ACTIVATION PROHIBITED" },
 	{ NVME_SC_OVERLAPPING_RANGE, "OVERLAPPING RANGE" },
 	{ NVME_SC_NS_INSUFFICIENT_CAPACITY, "NAMESPACE INSUFFICIENT CAPACITY" },
 	{ NVME_SC_NS_ID_UNAVAILABLE, "NAMESPACE IDENTIFIER UNAVAILABLE" },
 	{ NVME_SC_NS_ALREADY_ATTACHED, "NAMESPACE ALREADY ATTACHED" },
 	{ NVME_SC_NS_IS_PRIVATE, "NAMESPACE IS PRIVATE" },
 	{ NVME_SC_NS_NOT_ATTACHED, "NS NOT ATTACHED" },
 	{ NVME_SC_THIN_PROV_NOT_SUPPORTED, "THIN PROVISIONING NOT SUPPORTED" },
 	{ NVME_SC_CTRLR_LIST_INVALID, "CONTROLLER LIST INVALID" },
 	{ NVME_SC_SELF_TEST_IN_PROGRESS, "DEVICE SELF-TEST IN PROGRESS" },
 	{ NVME_SC_BOOT_PART_WRITE_PROHIB, "BOOT PARTITION WRITE PROHIBITED" },
 	{ NVME_SC_INVALID_CTRLR_ID, "INVALID CONTROLLER IDENTIFIER" },
 	{ NVME_SC_INVALID_SEC_CTRLR_STATE, "INVALID SECONDARY CONTROLLER STATE" },
 	{ NVME_SC_INVALID_NUM_OF_CTRLR_RESRC, "INVALID NUMBER OF CONTROLLER RESOURCES" },
 	{ NVME_SC_INVALID_RESOURCE_ID, "INVALID RESOURCE IDENTIFIER" },
 	{ NVME_SC_SANITIZE_PROHIBITED_WPMRE, "SANITIZE PROHIBITED WRITE PERSISTENT MEMORY REGION ENABLED" },
 	{ NVME_SC_ANA_GROUP_ID_INVALID, "ANA GROUP IDENTIFIED INVALID" },
 	{ NVME_SC_ANA_ATTACH_FAILED, "ANA ATTACH FAILED" },
 
 	{ NVME_SC_CONFLICTING_ATTRIBUTES, "CONFLICTING ATTRIBUTES" },
 	{ NVME_SC_INVALID_PROTECTION_INFO, "INVALID PROTECTION INFO" },
 	{ NVME_SC_ATTEMPTED_WRITE_TO_RO_PAGE, "WRITE TO RO PAGE" },
 	{ 0xFFFF, "COMMAND SPECIFIC" }
 };
 
 static struct nvme_status_string media_error_status[] = {
 	{ NVME_SC_WRITE_FAULTS, "WRITE FAULTS" },
 	{ NVME_SC_UNRECOVERED_READ_ERROR, "UNRECOVERED READ ERROR" },
 	{ NVME_SC_GUARD_CHECK_ERROR, "GUARD CHECK ERROR" },
 	{ NVME_SC_APPLICATION_TAG_CHECK_ERROR, "APPLICATION TAG CHECK ERROR" },
 	{ NVME_SC_REFERENCE_TAG_CHECK_ERROR, "REFERENCE TAG CHECK ERROR" },
 	{ NVME_SC_COMPARE_FAILURE, "COMPARE FAILURE" },
 	{ NVME_SC_ACCESS_DENIED, "ACCESS DENIED" },
 	{ NVME_SC_DEALLOCATED_OR_UNWRITTEN, "DEALLOCATED OR UNWRITTEN LOGICAL BLOCK" },
 	{ 0xFFFF, "MEDIA ERROR" }
 };
 
 static struct nvme_status_string path_related_status[] = {
 	{ NVME_SC_INTERNAL_PATH_ERROR, "INTERNAL PATH ERROR" },
 	{ NVME_SC_ASYMMETRIC_ACCESS_PERSISTENT_LOSS, "ASYMMETRIC ACCESS PERSISTENT LOSS" },
 	{ NVME_SC_ASYMMETRIC_ACCESS_INACCESSIBLE, "ASYMMETRIC ACCESS INACCESSIBLE" },
 	{ NVME_SC_ASYMMETRIC_ACCESS_TRANSITION, "ASYMMETRIC ACCESS TRANSITION" },
 	{ NVME_SC_CONTROLLER_PATHING_ERROR, "CONTROLLER PATHING ERROR" },
 	{ NVME_SC_HOST_PATHING_ERROR, "HOST PATHING ERROR" },
 	{ NVME_SC_COMMAND_ABOTHED_BY_HOST, "COMMAND ABOTHED BY HOST" },
 	{ 0xFFFF, "PATH RELATED" },
 };
 
 static const char *
 get_status_string(uint16_t sct, uint16_t sc)
 {
 	struct nvme_status_string *entry;
 
 	switch (sct) {
 	case NVME_SCT_GENERIC:
 		entry = generic_status;
 		break;
 	case NVME_SCT_COMMAND_SPECIFIC:
 		entry = command_specific_status;
 		break;
 	case NVME_SCT_MEDIA_ERROR:
 		entry = media_error_status;
 		break;
 	case NVME_SCT_PATH_RELATED:
 		entry = path_related_status;
 		break;
 	case NVME_SCT_VENDOR_SPECIFIC:
 		return ("VENDOR SPECIFIC");
 	default:
 		return ("RESERVED");
 	}
 
 	while (entry->sc != 0xFFFF) {
 		if (entry->sc == sc)
 			return (entry->str);
 		entry++;
 	}
 	return (entry->str);
 }
 
 static void
 nvme_qpair_print_completion(struct nvme_qpair *qpair,
     struct nvme_completion *cpl)
 {
 	uint16_t sct, sc;
 
 	sct = NVME_STATUS_GET_SCT(cpl->status);
 	sc = NVME_STATUS_GET_SC(cpl->status);
 
 	nvme_printf(qpair->ctrlr, "%s (%02x/%02x) sqid:%d cid:%d cdw0:%x\n",
 	    get_status_string(sct, sc), sct, sc, cpl->sqid, cpl->cid,
 	    cpl->cdw0);
 }
 
 static bool
 nvme_completion_is_retry(const struct nvme_completion *cpl)
 {
 	uint8_t sct, sc, dnr;
 
 	sct = NVME_STATUS_GET_SCT(cpl->status);
 	sc = NVME_STATUS_GET_SC(cpl->status);
 	dnr = NVME_STATUS_GET_DNR(cpl->status);	/* Do Not Retry Bit */
 
 	/*
 	 * TODO: spec is not clear how commands that are aborted due
 	 *  to TLER will be marked.  So for now, it seems
 	 *  NAMESPACE_NOT_READY is the only case where we should
 	 *  look at the DNR bit. Requests failed with ABORTED_BY_REQUEST
 	 *  set the DNR bit correctly since the driver controls that.
 	 */
 	switch (sct) {
 	case NVME_SCT_GENERIC:
 		switch (sc) {
 		case NVME_SC_ABORTED_BY_REQUEST:
 		case NVME_SC_NAMESPACE_NOT_READY:
 			if (dnr)
 				return (0);
 			else
 				return (1);
 		case NVME_SC_INVALID_OPCODE:
 		case NVME_SC_INVALID_FIELD:
 		case NVME_SC_COMMAND_ID_CONFLICT:
 		case NVME_SC_DATA_TRANSFER_ERROR:
 		case NVME_SC_ABORTED_POWER_LOSS:
 		case NVME_SC_INTERNAL_DEVICE_ERROR:
 		case NVME_SC_ABORTED_SQ_DELETION:
 		case NVME_SC_ABORTED_FAILED_FUSED:
 		case NVME_SC_ABORTED_MISSING_FUSED:
 		case NVME_SC_INVALID_NAMESPACE_OR_FORMAT:
 		case NVME_SC_COMMAND_SEQUENCE_ERROR:
 		case NVME_SC_LBA_OUT_OF_RANGE:
 		case NVME_SC_CAPACITY_EXCEEDED:
 		default:
 			return (0);
 		}
 	case NVME_SCT_COMMAND_SPECIFIC:
 	case NVME_SCT_MEDIA_ERROR:
 		return (0);
 	case NVME_SCT_PATH_RELATED:
 		switch (sc) {
 		case NVME_SC_INTERNAL_PATH_ERROR:
 			if (dnr)
 				return (0);
 			else
 				return (1);
 		default:
 			return (0);
 		}
 	case NVME_SCT_VENDOR_SPECIFIC:
 	default:
 		return (0);
 	}
 }
 
 static void
 nvme_qpair_complete_tracker(struct nvme_tracker *tr,
     struct nvme_completion *cpl, error_print_t print_on_error)
 {
 	struct nvme_qpair * qpair = tr->qpair;
 	struct nvme_request	*req;
 	bool			retry, error, retriable;
 
 	req = tr->req;
 	error = nvme_completion_is_error(cpl);
 	retriable = nvme_completion_is_retry(cpl);
 	retry = error && retriable && req->retries < nvme_retry_count;
 	if (retry)
 		qpair->num_retries++;
 	if (error && req->retries >= nvme_retry_count && retriable)
 		qpair->num_failures++;
 
 	if (error && (print_on_error == ERROR_PRINT_ALL ||
 		(!retry && print_on_error == ERROR_PRINT_NO_RETRY))) {
 		nvme_qpair_print_command(qpair, &req->cmd);
 		nvme_qpair_print_completion(qpair, cpl);
 	}
 
 	qpair->act_tr[cpl->cid] = NULL;
 
 	KASSERT(cpl->cid == req->cmd.cid, ("cpl cid does not match cmd cid\n"));
 
 	if (!retry) {
 		if (req->type != NVME_REQUEST_NULL) {
 			bus_dmamap_sync(qpair->dma_tag_payload,
 			    tr->payload_dma_map,
 			    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 		}
 		if (req->cb_fn)
 			req->cb_fn(req->cb_arg, cpl);
 	}
 
 	mtx_lock(&qpair->lock);
 
 	if (retry) {
 		req->retries++;
 		nvme_qpair_submit_tracker(qpair, tr);
 	} else {
 		if (req->type != NVME_REQUEST_NULL) {
 			bus_dmamap_unload(qpair->dma_tag_payload,
 			    tr->payload_dma_map);
 		}
 
 		nvme_free_request(req);
 		tr->req = NULL;
 
 		TAILQ_REMOVE(&qpair->outstanding_tr, tr, tailq);
 		TAILQ_INSERT_HEAD(&qpair->free_tr, tr, tailq);
 
 		/*
 		 * If the controller is in the middle of resetting, don't
 		 *  try to submit queued requests here - let the reset logic
 		 *  handle that instead.
 		 */
 		if (!STAILQ_EMPTY(&qpair->queued_req) &&
 		    !qpair->ctrlr->is_resetting) {
 			req = STAILQ_FIRST(&qpair->queued_req);
 			STAILQ_REMOVE_HEAD(&qpair->queued_req, stailq);
 			_nvme_qpair_submit_request(qpair, req);
 		}
 	}
 
 	mtx_unlock(&qpair->lock);
 }
 
 static void
 nvme_qpair_manual_complete_tracker(
     struct nvme_tracker *tr, uint32_t sct, uint32_t sc, uint32_t dnr,
     error_print_t print_on_error)
 {
 	struct nvme_completion	cpl;
 
 	memset(&cpl, 0, sizeof(cpl));
 
 	struct nvme_qpair * qpair = tr->qpair;
 
 	cpl.sqid = qpair->id;
 	cpl.cid = tr->cid;
 	cpl.status |= (sct & NVME_STATUS_SCT_MASK) << NVME_STATUS_SCT_SHIFT;
 	cpl.status |= (sc & NVME_STATUS_SC_MASK) << NVME_STATUS_SC_SHIFT;
 	cpl.status |= (dnr & NVME_STATUS_DNR_MASK) << NVME_STATUS_DNR_SHIFT;
 	nvme_qpair_complete_tracker(tr, &cpl, print_on_error);
 }
 
 void
 nvme_qpair_manual_complete_request(struct nvme_qpair *qpair,
     struct nvme_request *req, uint32_t sct, uint32_t sc)
 {
 	struct nvme_completion	cpl;
 	bool			error;
 
 	memset(&cpl, 0, sizeof(cpl));
 	cpl.sqid = qpair->id;
 	cpl.status |= (sct & NVME_STATUS_SCT_MASK) << NVME_STATUS_SCT_SHIFT;
 	cpl.status |= (sc & NVME_STATUS_SC_MASK) << NVME_STATUS_SC_SHIFT;
 
 	error = nvme_completion_is_error(&cpl);
 
 	if (error) {
 		nvme_qpair_print_command(qpair, &req->cmd);
 		nvme_qpair_print_completion(qpair, &cpl);
 	}
 
 	if (req->cb_fn)
 		req->cb_fn(req->cb_arg, &cpl);
 
 	nvme_free_request(req);
 }
 
 bool
 nvme_qpair_process_completions(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker	*tr;
 	struct nvme_completion	cpl;
 	int done = 0;
 	bool in_panic = dumping || SCHEDULER_STOPPED();
 
-	qpair->num_intr_handler_calls++;
-
 	/*
 	 * qpair is not enabled, likely because a controller reset is is in
 	 * progress.  Ignore the interrupt - any I/O that was associated with
-	 * this interrupt will get retried when the reset is complete.
+	 * this interrupt will get retried when the reset is complete. Any
+	 * pending completions for when we're in startup will be completed
+	 * as soon as initialization is complete and we start sending commands
+	 * to the device.
 	 */
 	if (qpair->recovery_state != RECOVERY_NONE)
 		return (false);
 
+	/*
+	 * Sanity check initialization. After we reset the hardware, the phase
+	 * is defined to be 1. So if we get here with zero prior calls and the
+	 * phase is 0, it means that we've lost a race between the
+	 * initialization and the ISR running. With the phase wrong, we'll
+	 * process a bunch of completions that aren't really completions leading
+	 * to a KASSERT below.
+	 */
+	KASSERT(!(qpair->num_intr_handler_calls == 0 && qpair->phase == 0),
+	    ("%s: Phase wrong for first interrupt call.",
+		device_get_nameunit(qpair->ctrlr->dev)));
+
+	qpair->num_intr_handler_calls++;
+
 	bus_dmamap_sync(qpair->dma_tag, qpair->queuemem_map,
 	    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 	/*
 	 * A panic can stop the CPU this routine is running on at any point.  If
 	 * we're called during a panic, complete the sq_head wrap protocol for
 	 * the case where we are interrupted just after the increment at 1
 	 * below, but before we can reset cq_head to zero at 2. Also cope with
 	 * the case where we do the zero at 2, but may or may not have done the
 	 * phase adjustment at step 3. The panic machinery flushes all pending
 	 * memory writes, so we can make these strong ordering assumptions
 	 * that would otherwise be unwise if we were racing in real time.
 	 */
 	if (__predict_false(in_panic)) {
 		if (qpair->cq_head == qpair->num_entries) {
 			/*
 			 * Here we know that we need to zero cq_head and then negate
 			 * the phase, which hasn't been assigned if cq_head isn't
 			 * zero due to the atomic_store_rel.
 			 */
 			qpair->cq_head = 0;
 			qpair->phase = !qpair->phase;
 		} else if (qpair->cq_head == 0) {
 			/*
 			 * In this case, we know that the assignment at 2
 			 * happened below, but we don't know if it 3 happened or
 			 * not. To do this, we look at the last completion
 			 * entry and set the phase to the opposite phase
 			 * that it has. This gets us back in sync
 			 */
 			cpl = qpair->cpl[qpair->num_entries - 1];
 			nvme_completion_swapbytes(&cpl);
 			qpair->phase = !NVME_STATUS_GET_P(cpl.status);
 		}
 	}
 
 	while (1) {
 		uint16_t status;
 
 		/*
 		 * We need to do this dance to avoid a race between the host and
 		 * the device where the device overtakes the host while the host
 		 * is reading this record, leaving the status field 'new' and
 		 * the sqhd and cid fields potentially stale. If the phase
 		 * doesn't match, that means status hasn't yet been updated and
 		 * we'll get any pending changes next time. It also means that
 		 * the phase must be the same the second time. We have to sync
 		 * before reading to ensure any bouncing completes.
 		 */
 		status = le16toh(qpair->cpl[qpair->cq_head].status);
 		if (NVME_STATUS_GET_P(status) != qpair->phase)
 			break;
 
 		bus_dmamap_sync(qpair->dma_tag, qpair->queuemem_map,
 		    BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE);
 		cpl = qpair->cpl[qpair->cq_head];
 		nvme_completion_swapbytes(&cpl);
 
 		KASSERT(
 		    NVME_STATUS_GET_P(status) == NVME_STATUS_GET_P(cpl.status),
 		    ("Phase unexpectedly inconsistent"));
 
 		tr = qpair->act_tr[cpl.cid];
 
 		if (tr != NULL) {
 			nvme_qpair_complete_tracker(tr, &cpl, ERROR_PRINT_ALL);
 			qpair->sq_head = cpl.sqhd;
 			done++;
 		} else if (!in_panic) {
 			/*
 			 * A missing tracker is normally an error.  However, a
 			 * panic can stop the CPU this routine is running on
 			 * after completing an I/O but before updating
 			 * qpair->cq_head at 1 below.  Later, we re-enter this
 			 * routine to poll I/O associated with the kernel
 			 * dump. We find that the tr has been set to null before
 			 * calling the completion routine.  If it hasn't
 			 * completed (or it triggers a panic), then '1' below
 			 * won't have updated cq_head. Rather than panic again,
 			 * ignore this condition because it's not unexpected.
 			 */
 			nvme_printf(qpair->ctrlr,
 			    "cpl does not map to outstanding cmd\n");
 			/* nvme_dump_completion expects device endianess */
 			nvme_dump_completion(&qpair->cpl[qpair->cq_head]);
 			KASSERT(0, ("received completion for unknown cmd"));
 		}
 
 		/*
 		 * There's a number of races with the following (see above) when
 		 * the system panics. We compensate for each one of them by
 		 * using the atomic store to force strong ordering (at least when
 		 * viewed in the aftermath of a panic).
 		 */
 		if (++qpair->cq_head == qpair->num_entries) {		/* 1 */
 			atomic_store_rel_int(&qpair->cq_head, 0);	/* 2 */
 			qpair->phase = !qpair->phase;			/* 3 */
 		}
 
 		bus_space_write_4(qpair->ctrlr->bus_tag, qpair->ctrlr->bus_handle,
 		    qpair->cq_hdbl_off, qpair->cq_head);
 	}
 	return (done != 0);
 }
 
 static void
 nvme_qpair_msi_handler(void *arg)
 {
 	struct nvme_qpair *qpair = arg;
 
 	nvme_qpair_process_completions(qpair);
 }
 
 int
 nvme_qpair_construct(struct nvme_qpair *qpair,
     uint32_t num_entries, uint32_t num_trackers,
     struct nvme_controller *ctrlr)
 {
 	struct nvme_tracker	*tr;
 	size_t			cmdsz, cplsz, prpsz, allocsz, prpmemsz;
 	uint64_t		queuemem_phys, prpmem_phys, list_phys;
 	uint8_t			*queuemem, *prpmem, *prp_list;
 	int			i, err;
 
 	qpair->vector = ctrlr->msi_count > 1 ? qpair->id : 0;
 	qpair->num_entries = num_entries;
 	qpair->num_trackers = num_trackers;
 	qpair->ctrlr = ctrlr;
 
 	mtx_init(&qpair->lock, "nvme qpair lock", NULL, MTX_DEF);
 
 	/* Note: NVMe PRP format is restricted to 4-byte alignment. */
 	err = bus_dma_tag_create(bus_get_dma_tag(ctrlr->dev),
 	    4, PAGE_SIZE, BUS_SPACE_MAXADDR,
 	    BUS_SPACE_MAXADDR, NULL, NULL, ctrlr->max_xfer_size,
 	    btoc(ctrlr->max_xfer_size) + 1, PAGE_SIZE, 0,
 	    NULL, NULL, &qpair->dma_tag_payload);
 	if (err != 0) {
 		nvme_printf(ctrlr, "payload tag create failed %d\n", err);
 		goto out;
 	}
 
 	/*
 	 * Each component must be page aligned, and individual PRP lists
 	 * cannot cross a page boundary.
 	 */
 	cmdsz = qpair->num_entries * sizeof(struct nvme_command);
 	cmdsz = roundup2(cmdsz, PAGE_SIZE);
 	cplsz = qpair->num_entries * sizeof(struct nvme_completion);
 	cplsz = roundup2(cplsz, PAGE_SIZE);
 	/*
 	 * For commands requiring more than 2 PRP entries, one PRP will be
 	 * embedded in the command (prp1), and the rest of the PRP entries
 	 * will be in a list pointed to by the command (prp2).
 	 */
 	prpsz = sizeof(uint64_t) * btoc(ctrlr->max_xfer_size);
 	prpmemsz = qpair->num_trackers * prpsz;
 	allocsz = cmdsz + cplsz + prpmemsz;
 
 	err = bus_dma_tag_create(bus_get_dma_tag(ctrlr->dev),
 	    PAGE_SIZE, 0, BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL,
 	    allocsz, 1, allocsz, 0, NULL, NULL, &qpair->dma_tag);
 	if (err != 0) {
 		nvme_printf(ctrlr, "tag create failed %d\n", err);
 		goto out;
 	}
 	bus_dma_tag_set_domain(qpair->dma_tag, qpair->domain);
 
 	if (bus_dmamem_alloc(qpair->dma_tag, (void **)&queuemem,
 	     BUS_DMA_COHERENT | BUS_DMA_NOWAIT, &qpair->queuemem_map)) {
 		nvme_printf(ctrlr, "failed to alloc qpair memory\n");
 		goto out;
 	}
 
 	if (bus_dmamap_load(qpair->dma_tag, qpair->queuemem_map,
 	    queuemem, allocsz, nvme_single_map, &queuemem_phys, 0) != 0) {
 		nvme_printf(ctrlr, "failed to load qpair memory\n");
 		bus_dmamem_free(qpair->dma_tag, qpair->cmd,
 		    qpair->queuemem_map);
 		goto out;
 	}
 
 	qpair->num_cmds = 0;
 	qpair->num_intr_handler_calls = 0;
 	qpair->num_retries = 0;
 	qpair->num_failures = 0;
 	qpair->cmd = (struct nvme_command *)queuemem;
 	qpair->cpl = (struct nvme_completion *)(queuemem + cmdsz);
 	prpmem = (uint8_t *)(queuemem + cmdsz + cplsz);
 	qpair->cmd_bus_addr = queuemem_phys;
 	qpair->cpl_bus_addr = queuemem_phys + cmdsz;
 	prpmem_phys = queuemem_phys + cmdsz + cplsz;
 
 	callout_init(&qpair->timer, 1);
 	qpair->timer_armed = false;
 	qpair->recovery_state = RECOVERY_WAITING;
 
 	/*
 	 * Calcuate the stride of the doorbell register. Many emulators set this
 	 * value to correspond to a cache line. However, some hardware has set
 	 * it to various small values.
 	 */
 	qpair->sq_tdbl_off = nvme_mmio_offsetof(doorbell[0]) +
 	    (qpair->id << (ctrlr->dstrd + 1));
 	qpair->cq_hdbl_off = nvme_mmio_offsetof(doorbell[0]) +
 	    (qpair->id << (ctrlr->dstrd + 1)) + (1 << ctrlr->dstrd);
 
 	TAILQ_INIT(&qpair->free_tr);
 	TAILQ_INIT(&qpair->outstanding_tr);
 	STAILQ_INIT(&qpair->queued_req);
 
 	list_phys = prpmem_phys;
 	prp_list = prpmem;
 	for (i = 0; i < qpair->num_trackers; i++) {
 		if (list_phys + prpsz > prpmem_phys + prpmemsz) {
 			qpair->num_trackers = i;
 			break;
 		}
 
 		/*
 		 * Make sure that the PRP list for this tracker doesn't
 		 * overflow to another page.
 		 */
 		if (trunc_page(list_phys) !=
 		    trunc_page(list_phys + prpsz - 1)) {
 			list_phys = roundup2(list_phys, PAGE_SIZE);
 			prp_list =
 			    (uint8_t *)roundup2((uintptr_t)prp_list, PAGE_SIZE);
 		}
 
 		tr = malloc_domainset(sizeof(*tr), M_NVME,
 		    DOMAINSET_PREF(qpair->domain), M_ZERO | M_WAITOK);
 		bus_dmamap_create(qpair->dma_tag_payload, 0,
 		    &tr->payload_dma_map);
 		tr->cid = i;
 		tr->qpair = qpair;
 		tr->prp = (uint64_t *)prp_list;
 		tr->prp_bus_addr = list_phys;
 		TAILQ_INSERT_HEAD(&qpair->free_tr, tr, tailq);
 		list_phys += prpsz;
 		prp_list += prpsz;
 	}
 
 	if (qpair->num_trackers == 0) {
 		nvme_printf(ctrlr, "failed to allocate enough trackers\n");
 		goto out;
 	}
 
 	qpair->act_tr = malloc_domainset(sizeof(struct nvme_tracker *) *
 	    qpair->num_entries, M_NVME, DOMAINSET_PREF(qpair->domain),
 	    M_ZERO | M_WAITOK);
 
 	if (ctrlr->msi_count > 1) {
 		/*
 		 * MSI-X vector resource IDs start at 1, so we add one to
 		 *  the queue's vector to get the corresponding rid to use.
 		 */
 		qpair->rid = qpair->vector + 1;
 
 		qpair->res = bus_alloc_resource_any(ctrlr->dev, SYS_RES_IRQ,
 		    &qpair->rid, RF_ACTIVE);
 		if (qpair->res == NULL) {
 			nvme_printf(ctrlr, "unable to allocate MSI\n");
 			goto out;
 		}
 		if (bus_setup_intr(ctrlr->dev, qpair->res,
 		    INTR_TYPE_MISC | INTR_MPSAFE, NULL,
 		    nvme_qpair_msi_handler, qpair, &qpair->tag) != 0) {
 			nvme_printf(ctrlr, "unable to setup MSI\n");
 			goto out;
 		}
 		if (qpair->id == 0) {
 			bus_describe_intr(ctrlr->dev, qpair->res, qpair->tag,
 			    "admin");
 		} else {
 			bus_describe_intr(ctrlr->dev, qpair->res, qpair->tag,
 			    "io%d", qpair->id - 1);
 		}
 	}
 
 	return (0);
 
 out:
 	nvme_qpair_destroy(qpair);
 	return (ENOMEM);
 }
 
 static void
 nvme_qpair_destroy(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker	*tr;
 
 	callout_drain(&qpair->timer);
 
 	if (qpair->tag) {
 		bus_teardown_intr(qpair->ctrlr->dev, qpair->res, qpair->tag);
 		qpair->tag = NULL;
 	}
 
 	if (qpair->act_tr) {
 		free(qpair->act_tr, M_NVME);
 		qpair->act_tr = NULL;
 	}
 
 	while (!TAILQ_EMPTY(&qpair->free_tr)) {
 		tr = TAILQ_FIRST(&qpair->free_tr);
 		TAILQ_REMOVE(&qpair->free_tr, tr, tailq);
 		bus_dmamap_destroy(qpair->dma_tag_payload,
 		    tr->payload_dma_map);
 		free(tr, M_NVME);
 	}
 
 	if (qpair->cmd != NULL) {
 		bus_dmamap_unload(qpair->dma_tag, qpair->queuemem_map);
 		bus_dmamem_free(qpair->dma_tag, qpair->cmd,
 		    qpair->queuemem_map);
 		qpair->cmd = NULL;
 	}
 
 	if (qpair->dma_tag) {
 		bus_dma_tag_destroy(qpair->dma_tag);
 		qpair->dma_tag = NULL;
 	}
 
 	if (qpair->dma_tag_payload) {
 		bus_dma_tag_destroy(qpair->dma_tag_payload);
 		qpair->dma_tag_payload = NULL;
 	}
 
 	if (mtx_initialized(&qpair->lock))
 		mtx_destroy(&qpair->lock);
 
 	if (qpair->res) {
 		bus_release_resource(qpair->ctrlr->dev, SYS_RES_IRQ,
 		    rman_get_rid(qpair->res), qpair->res);
 		qpair->res = NULL;
 	}
 }
 
 static void
 nvme_admin_qpair_abort_aers(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker	*tr;
 
 	tr = TAILQ_FIRST(&qpair->outstanding_tr);
 	while (tr != NULL) {
 		if (tr->req->cmd.opc == NVME_OPC_ASYNC_EVENT_REQUEST) {
 			nvme_qpair_manual_complete_tracker(tr,
 			    NVME_SCT_GENERIC, NVME_SC_ABORTED_SQ_DELETION, 0,
 			    ERROR_PRINT_NONE);
 			tr = TAILQ_FIRST(&qpair->outstanding_tr);
 		} else {
 			tr = TAILQ_NEXT(tr, tailq);
 		}
 	}
 }
 
 void
 nvme_admin_qpair_destroy(struct nvme_qpair *qpair)
 {
 
 	nvme_admin_qpair_abort_aers(qpair);
 	nvme_qpair_destroy(qpair);
 }
 
 void
 nvme_io_qpair_destroy(struct nvme_qpair *qpair)
 {
 
 	nvme_qpair_destroy(qpair);
 }
 
 static void
 nvme_qpair_timeout(void *arg)
 {
 	struct nvme_qpair	*qpair = arg;
 	struct nvme_controller	*ctrlr = qpair->ctrlr;
 	struct nvme_tracker	*tr;
 	struct nvme_tracker	*tr_temp;
 	sbintime_t		now;
 	bool			idle;
 	uint32_t		csts;
 	uint8_t			cfs;
 
 	mtx_lock(&qpair->lock);
 	idle = TAILQ_EMPTY(&qpair->outstanding_tr);
 again:
 	switch (qpair->recovery_state) {
 	case RECOVERY_NONE:
 		if (idle)
 			break;
 		now = getsbinuptime();
 		TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
 			if (now > tr->deadline && tr->deadline != 0) {
 				/*
 				 * We're now passed our earliest deadline. We
 				 * need to do expensive things to cope, but next
 				 * time. Flag that and close the door to any
 				 * further processing.
 				 */
 				qpair->recovery_state = RECOVERY_START;
 				nvme_printf(ctrlr, "RECOVERY_START %jd vs %jd\n",
 				    (uintmax_t)now, (uintmax_t)tr->deadline);
 				break;
 			}
 		}
 		break;
 	case RECOVERY_START:
 		/*
 		 * Read csts to get value of cfs - controller fatal status.
 		 * If no fatal status, try to call the completion routine, and
 		 * if completes transactions, report a missed interrupt and
 		 * return (this may need to be rate limited). Otherwise, if
 		 * aborts are enabled and the controller is not reporting
 		 * fatal status, abort the command. Otherwise, just reset the
 		 * controller and hope for the best.
 		 */
 		csts = nvme_mmio_read_4(ctrlr, csts);
 		cfs = (csts >> NVME_CSTS_REG_CFS_SHIFT) & NVME_CSTS_REG_CFS_MASK;
 		if (cfs) {
 			nvme_printf(ctrlr, "Controller in fatal status, resetting\n");
 			qpair->recovery_state = RECOVERY_RESET;
 			goto again;
 		}
 		mtx_unlock(&qpair->lock);
 		if (nvme_qpair_process_completions(qpair)) {
 			nvme_printf(ctrlr, "Completions present in output without an interrupt\n");
 			qpair->recovery_state = RECOVERY_NONE;
 		} else {
 			nvme_printf(ctrlr, "timeout with nothing complete, resetting\n");
 			qpair->recovery_state = RECOVERY_RESET;
 			mtx_lock(&qpair->lock);
 			goto again;
 		}
 		mtx_lock(&qpair->lock);
 		break;
 	case RECOVERY_RESET:
 		/*
 		 * If we get here due to a possible surprise hot-unplug event,
 		 * then we let nvme_ctrlr_reset confirm and fail the
 		 * controller.
 		 */
 		nvme_printf(ctrlr, "Resetting controller due to a timeout%s.\n",
 		    cfs ? " and fatal error status" : "");
 		nvme_printf(ctrlr, "RECOVERY_WAITING\n");
 		qpair->recovery_state = RECOVERY_WAITING;
 		nvme_ctrlr_reset(ctrlr);
 		break;
 	case RECOVERY_WAITING:
 		nvme_printf(ctrlr, "waiting\n");
 		break;
 	}
 
 	/*
 	 * Rearm the timeout.
 	 */
 	if (!idle) {
 		callout_schedule(&qpair->timer, hz / 2);
 	} else {
 		qpair->timer_armed = false;
 	}
 	mtx_unlock(&qpair->lock);
 }
 
 /*
  * Submit the tracker to the hardware. Must already be in the
  * outstanding queue when called.
  */
 void
 nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr)
 {
 	struct nvme_request	*req;
 	struct nvme_controller	*ctrlr;
 	int timeout;
 
 	mtx_assert(&qpair->lock, MA_OWNED);
 
 	req = tr->req;
 	req->cmd.cid = tr->cid;
 	qpair->act_tr[tr->cid] = tr;
 	ctrlr = qpair->ctrlr;
 
 	if (req->timeout) {
 		if (req->cb_fn == nvme_completion_poll_cb)
 			timeout = 1;
 		else
 			timeout = ctrlr->timeout_period;
 		tr->deadline = getsbinuptime() + timeout * SBT_1S;
 		if (!qpair->timer_armed) {
 			qpair->timer_armed = true;
 			callout_reset_on(&qpair->timer, hz / 2,
 			    nvme_qpair_timeout, qpair, qpair->cpu);
 		}
 	} else
 		tr->deadline = SBT_MAX;
 
 	/* Copy the command from the tracker to the submission queue. */
 	memcpy(&qpair->cmd[qpair->sq_tail], &req->cmd, sizeof(req->cmd));
 
 	if (++qpair->sq_tail == qpair->num_entries)
 		qpair->sq_tail = 0;
 
 	bus_dmamap_sync(qpair->dma_tag, qpair->queuemem_map,
 	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
 	bus_space_write_4(qpair->ctrlr->bus_tag, qpair->ctrlr->bus_handle,
 	    qpair->sq_tdbl_off, qpair->sq_tail);
 	qpair->num_cmds++;
 }
 
 static void
 nvme_payload_map(void *arg, bus_dma_segment_t *seg, int nseg, int error)
 {
 	struct nvme_tracker 	*tr = arg;
 	uint32_t		cur_nseg;
 
 	/*
 	 * If the mapping operation failed, return immediately.  The caller
 	 *  is responsible for detecting the error status and failing the
 	 *  tracker manually.
 	 */
 	if (error != 0) {
 		nvme_printf(tr->qpair->ctrlr,
 		    "nvme_payload_map err %d\n", error);
 		return;
 	}
 
 	/*
 	 * Note that we specified PAGE_SIZE for alignment and max
 	 *  segment size when creating the bus dma tags.  So here
 	 *  we can safely just transfer each segment to its
 	 *  associated PRP entry.
 	 */
 	tr->req->cmd.prp1 = htole64(seg[0].ds_addr);
 
 	if (nseg == 2) {
 		tr->req->cmd.prp2 = htole64(seg[1].ds_addr);
 	} else if (nseg > 2) {
 		cur_nseg = 1;
 		tr->req->cmd.prp2 = htole64((uint64_t)tr->prp_bus_addr);
 		while (cur_nseg < nseg) {
 			tr->prp[cur_nseg-1] =
 			    htole64((uint64_t)seg[cur_nseg].ds_addr);
 			cur_nseg++;
 		}
 	} else {
 		/*
 		 * prp2 should not be used by the controller
 		 *  since there is only one segment, but set
 		 *  to 0 just to be safe.
 		 */
 		tr->req->cmd.prp2 = 0;
 	}
 
 	bus_dmamap_sync(tr->qpair->dma_tag_payload, tr->payload_dma_map,
 	    BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
 	nvme_qpair_submit_tracker(tr->qpair, tr);
 }
 
 static void
 _nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req)
 {
 	struct nvme_tracker	*tr;
 	int			err = 0;
 
 	mtx_assert(&qpair->lock, MA_OWNED);
 
 	tr = TAILQ_FIRST(&qpair->free_tr);
 	req->qpair = qpair;
 
 	if (tr == NULL || qpair->recovery_state != RECOVERY_NONE) {
 		/*
 		 * No tracker is available, or the qpair is disabled due to
 		 *  an in-progress controller-level reset or controller
 		 *  failure.
 		 */
 
 		if (qpair->ctrlr->is_failed) {
 			/*
 			 * The controller has failed, so fail the request.
 			 */
 			nvme_qpair_manual_complete_request(qpair, req,
 			    NVME_SCT_GENERIC, NVME_SC_ABORTED_BY_REQUEST);
 		} else {
 			/*
 			 * Put the request on the qpair's request queue to be
 			 *  processed when a tracker frees up via a command
 			 *  completion or when the controller reset is
 			 *  completed.
 			 */
 			STAILQ_INSERT_TAIL(&qpair->queued_req, req, stailq);
 		}
 		return;
 	}
 
 	TAILQ_REMOVE(&qpair->free_tr, tr, tailq);
 	TAILQ_INSERT_TAIL(&qpair->outstanding_tr, tr, tailq);
 	if (!qpair->timer_armed)
 		tr->deadline = SBT_MAX;
 	tr->req = req;
 
 	switch (req->type) {
 	case NVME_REQUEST_VADDR:
 		KASSERT(req->payload_size <= qpair->ctrlr->max_xfer_size,
 		    ("payload_size (%d) exceeds max_xfer_size (%d)\n",
 		    req->payload_size, qpair->ctrlr->max_xfer_size));
 		err = bus_dmamap_load(tr->qpair->dma_tag_payload,
 		    tr->payload_dma_map, req->u.payload, req->payload_size,
 		    nvme_payload_map, tr, 0);
 		if (err != 0)
 			nvme_printf(qpair->ctrlr,
 			    "bus_dmamap_load returned 0x%x!\n", err);
 		break;
 	case NVME_REQUEST_NULL:
 		nvme_qpair_submit_tracker(tr->qpair, tr);
 		break;
 	case NVME_REQUEST_BIO:
 		KASSERT(req->u.bio->bio_bcount <= qpair->ctrlr->max_xfer_size,
 		    ("bio->bio_bcount (%jd) exceeds max_xfer_size (%d)\n",
 		    (intmax_t)req->u.bio->bio_bcount,
 		    qpair->ctrlr->max_xfer_size));
 		err = bus_dmamap_load_bio(tr->qpair->dma_tag_payload,
 		    tr->payload_dma_map, req->u.bio, nvme_payload_map, tr, 0);
 		if (err != 0)
 			nvme_printf(qpair->ctrlr,
 			    "bus_dmamap_load_bio returned 0x%x!\n", err);
 		break;
 	case NVME_REQUEST_CCB:
 		err = bus_dmamap_load_ccb(tr->qpair->dma_tag_payload,
 		    tr->payload_dma_map, req->u.payload,
 		    nvme_payload_map, tr, 0);
 		if (err != 0)
 			nvme_printf(qpair->ctrlr,
 			    "bus_dmamap_load_ccb returned 0x%x!\n", err);
 		break;
 	default:
 		panic("unknown nvme request type 0x%x\n", req->type);
 		break;
 	}
 
 	if (err != 0) {
 		/*
 		 * The dmamap operation failed, so we manually fail the
 		 *  tracker here with DATA_TRANSFER_ERROR status.
 		 *
 		 * nvme_qpair_manual_complete_tracker must not be called
 		 *  with the qpair lock held.
 		 */
 		mtx_unlock(&qpair->lock);
 		nvme_qpair_manual_complete_tracker(tr, NVME_SCT_GENERIC,
 		    NVME_SC_DATA_TRANSFER_ERROR, DO_NOT_RETRY, ERROR_PRINT_ALL);
 		mtx_lock(&qpair->lock);
 	}
 }
 
 void
 nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req)
 {
 
 	mtx_lock(&qpair->lock);
 	_nvme_qpair_submit_request(qpair, req);
 	mtx_unlock(&qpair->lock);
 }
 
 static void
 nvme_qpair_enable(struct nvme_qpair *qpair)
 {
 	mtx_assert(&qpair->lock, MA_OWNED);
 
 	qpair->recovery_state = RECOVERY_NONE;
 }
 
 void
 nvme_qpair_reset(struct nvme_qpair *qpair)
 {
 
 	qpair->sq_head = qpair->sq_tail = qpair->cq_head = 0;
 
 	/*
 	 * First time through the completion queue, HW will set phase
 	 *  bit on completions to 1.  So set this to 1 here, indicating
 	 *  we're looking for a 1 to know which entries have completed.
 	 *  we'll toggle the bit each time when the completion queue
 	 *  rolls over.
 	 */
 	qpair->phase = 1;
 
 	memset(qpair->cmd, 0,
 	    qpair->num_entries * sizeof(struct nvme_command));
 	memset(qpair->cpl, 0,
 	    qpair->num_entries * sizeof(struct nvme_completion));
 }
 
 void
 nvme_admin_qpair_enable(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker		*tr;
 	struct nvme_tracker		*tr_temp;
 
 	/*
 	 * Manually abort each outstanding admin command.  Do not retry
 	 *  admin commands found here, since they will be left over from
 	 *  a controller reset and its likely the context in which the
 	 *  command was issued no longer applies.
 	 */
 	TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
 		nvme_printf(qpair->ctrlr,
 		    "aborting outstanding admin command\n");
 		nvme_qpair_manual_complete_tracker(tr, NVME_SCT_GENERIC,
 		    NVME_SC_ABORTED_BY_REQUEST, DO_NOT_RETRY, ERROR_PRINT_ALL);
 	}
 
 	mtx_lock(&qpair->lock);
 	nvme_qpair_enable(qpair);
 	mtx_unlock(&qpair->lock);
 }
 
 void
 nvme_io_qpair_enable(struct nvme_qpair *qpair)
 {
 	STAILQ_HEAD(, nvme_request)	temp;
 	struct nvme_tracker		*tr;
 	struct nvme_tracker		*tr_temp;
 	struct nvme_request		*req;
 
 	/*
 	 * Manually abort each outstanding I/O.  This normally results in a
 	 *  retry, unless the retry count on the associated request has
 	 *  reached its limit.
 	 */
 	TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
 		nvme_printf(qpair->ctrlr, "aborting outstanding i/o\n");
 		nvme_qpair_manual_complete_tracker(tr, NVME_SCT_GENERIC,
 		    NVME_SC_ABORTED_BY_REQUEST, 0, ERROR_PRINT_NO_RETRY);
 	}
 
 	mtx_lock(&qpair->lock);
 
 	nvme_qpair_enable(qpair);
 
 	STAILQ_INIT(&temp);
 	STAILQ_SWAP(&qpair->queued_req, &temp, nvme_request);
 
 	while (!STAILQ_EMPTY(&temp)) {
 		req = STAILQ_FIRST(&temp);
 		STAILQ_REMOVE_HEAD(&temp, stailq);
 		nvme_printf(qpair->ctrlr, "resubmitting queued i/o\n");
 		nvme_qpair_print_command(qpair, &req->cmd);
 		_nvme_qpair_submit_request(qpair, req);
 	}
 
 	mtx_unlock(&qpair->lock);
 }
 
 static void
 nvme_qpair_disable(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker	*tr, *tr_temp;
 
 	mtx_lock(&qpair->lock);
 	qpair->recovery_state = RECOVERY_WAITING;
 	TAILQ_FOREACH_SAFE(tr, &qpair->outstanding_tr, tailq, tr_temp) {
 		tr->deadline = SBT_MAX;
 	}
 	mtx_unlock(&qpair->lock);
 }
 
 void
 nvme_admin_qpair_disable(struct nvme_qpair *qpair)
 {
 
 	nvme_qpair_disable(qpair);
 	nvme_admin_qpair_abort_aers(qpair);
 }
 
 void
 nvme_io_qpair_disable(struct nvme_qpair *qpair)
 {
 
 	nvme_qpair_disable(qpair);
 }
 
 void
 nvme_qpair_fail(struct nvme_qpair *qpair)
 {
 	struct nvme_tracker		*tr;
 	struct nvme_request		*req;
 
 	if (!mtx_initialized(&qpair->lock))
 		return;
 
 	mtx_lock(&qpair->lock);
 
 	while (!STAILQ_EMPTY(&qpair->queued_req)) {
 		req = STAILQ_FIRST(&qpair->queued_req);
 		STAILQ_REMOVE_HEAD(&qpair->queued_req, stailq);
 		nvme_printf(qpair->ctrlr, "failing queued i/o\n");
 		mtx_unlock(&qpair->lock);
 		nvme_qpair_manual_complete_request(qpair, req, NVME_SCT_GENERIC,
 		    NVME_SC_ABORTED_BY_REQUEST);
 		mtx_lock(&qpair->lock);
 	}
 
 	/* Manually abort each outstanding I/O. */
 	while (!TAILQ_EMPTY(&qpair->outstanding_tr)) {
 		tr = TAILQ_FIRST(&qpair->outstanding_tr);
 		/*
 		 * Do not remove the tracker.  The abort_tracker path will
 		 *  do that for us.
 		 */
 		nvme_printf(qpair->ctrlr, "failing outstanding i/o\n");
 		mtx_unlock(&qpair->lock);
 		nvme_qpair_manual_complete_tracker(tr, NVME_SCT_GENERIC,
 		    NVME_SC_ABORTED_BY_REQUEST, DO_NOT_RETRY, ERROR_PRINT_ALL);
 		mtx_lock(&qpair->lock);
 	}
 
 	mtx_unlock(&qpair->lock);
 }
diff --git a/sys/dev/nvme/nvme_sysctl.c b/sys/dev/nvme/nvme_sysctl.c
index bbf9a40ee7fe..1f1e1ce4a628 100644
--- a/sys/dev/nvme/nvme_sysctl.c
+++ b/sys/dev/nvme/nvme_sysctl.c
@@ -1,358 +1,363 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (C) 2012-2016 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include "opt_nvme.h"
 
 #include <sys/param.h>
 #include <sys/bus.h>
 #include <sys/sysctl.h>
 
 #include "nvme_private.h"
 
 #ifndef NVME_USE_NVD
 #define NVME_USE_NVD 1
 #endif
 
 int nvme_use_nvd = NVME_USE_NVD;
 bool nvme_verbose_cmd_dump = false;
 
 SYSCTL_NODE(_hw, OID_AUTO, nvme, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
     "NVMe sysctl tunables");
 SYSCTL_INT(_hw_nvme, OID_AUTO, use_nvd, CTLFLAG_RDTUN,
     &nvme_use_nvd, 1, "1 = Create NVD devices, 0 = Create NDA devices");
 SYSCTL_BOOL(_hw_nvme, OID_AUTO, verbose_cmd_dump, CTLFLAG_RWTUN,
     &nvme_verbose_cmd_dump, 0,
     "enable verbose command printing when a command fails");
 
 static void
 nvme_dump_queue(struct nvme_qpair *qpair)
 {
 	struct nvme_completion *cpl;
 	struct nvme_command *cmd;
 	int i;
 
 	printf("id:%04Xh phase:%d\n", qpair->id, qpair->phase);
 
 	printf("Completion queue:\n");
 	for (i = 0; i < qpair->num_entries; i++) {
 		cpl = &qpair->cpl[i];
 		printf("%05d: ", i);
 		nvme_dump_completion(cpl);
 	}
 
 	printf("Submission queue:\n");
 	for (i = 0; i < qpair->num_entries; i++) {
 		cmd = &qpair->cmd[i];
 		printf("%05d: ", i);
 		nvme_dump_command(cmd);
 	}
 }
 
 static int
 nvme_sysctl_dump_debug(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_qpair 	*qpair = arg1;
 	uint32_t		val = 0;
 
 	int error = sysctl_handle_int(oidp, &val, 0, req);
 
 	if (error)
 		return (error);
 
 	if (val != 0)
 		nvme_dump_queue(qpair);
 
 	return (0);
 }
 
 static int
 nvme_sysctl_int_coal_time(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller *ctrlr = arg1;
 	uint32_t oldval = ctrlr->int_coal_time;
 	int error = sysctl_handle_int(oidp, &ctrlr->int_coal_time, 0,
 	    req);
 
 	if (error)
 		return (error);
 
 	if (oldval != ctrlr->int_coal_time)
 		nvme_ctrlr_cmd_set_interrupt_coalescing(ctrlr,
 		    ctrlr->int_coal_time, ctrlr->int_coal_threshold, NULL,
 		    NULL);
 
 	return (0);
 }
 
 static int
 nvme_sysctl_int_coal_threshold(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller *ctrlr = arg1;
 	uint32_t oldval = ctrlr->int_coal_threshold;
 	int error = sysctl_handle_int(oidp, &ctrlr->int_coal_threshold, 0,
 	    req);
 
 	if (error)
 		return (error);
 
 	if (oldval != ctrlr->int_coal_threshold)
 		nvme_ctrlr_cmd_set_interrupt_coalescing(ctrlr,
 		    ctrlr->int_coal_time, ctrlr->int_coal_threshold, NULL,
 		    NULL);
 
 	return (0);
 }
 
 static int
 nvme_sysctl_timeout_period(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller *ctrlr = arg1;
 	uint32_t newval = ctrlr->timeout_period;
 	int error = sysctl_handle_int(oidp, &newval, 0, req);
 
 	if (error || (req->newptr == NULL))
 		return (error);
 
 	if (newval > NVME_MAX_TIMEOUT_PERIOD ||
 	    newval < NVME_MIN_TIMEOUT_PERIOD) {
 		return (EINVAL);
 	} else {
 		ctrlr->timeout_period = newval;
 	}
 
 	return (0);
 }
 
 static void
 nvme_qpair_reset_stats(struct nvme_qpair *qpair)
 {
 
+	/*
+	 * Reset the values. Due to sanity checks in
+	 * nvme_qpair_process_completions, we reset the number of interrupt
+	 * calls to 1.
+	 */
 	qpair->num_cmds = 0;
-	qpair->num_intr_handler_calls = 0;
+	qpair->num_intr_handler_calls = 1;
 	qpair->num_retries = 0;
 	qpair->num_failures = 0;
 }
 
 static int
 nvme_sysctl_num_cmds(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller 	*ctrlr = arg1;
 	int64_t			num_cmds = 0;
 	int			i;
 
 	num_cmds = ctrlr->adminq.num_cmds;
 
 	for (i = 0; i < ctrlr->num_io_queues; i++)
 		num_cmds += ctrlr->ioq[i].num_cmds;
 
 	return (sysctl_handle_64(oidp, &num_cmds, 0, req));
 }
 
 static int
 nvme_sysctl_num_intr_handler_calls(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller 	*ctrlr = arg1;
 	int64_t			num_intr_handler_calls = 0;
 	int			i;
 
 	num_intr_handler_calls = ctrlr->adminq.num_intr_handler_calls;
 
 	for (i = 0; i < ctrlr->num_io_queues; i++)
 		num_intr_handler_calls += ctrlr->ioq[i].num_intr_handler_calls;
 
 	return (sysctl_handle_64(oidp, &num_intr_handler_calls, 0, req));
 }
 
 static int
 nvme_sysctl_num_retries(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller 	*ctrlr = arg1;
 	int64_t			num_retries = 0;
 	int			i;
 
 	num_retries = ctrlr->adminq.num_retries;
 
 	for (i = 0; i < ctrlr->num_io_queues; i++)
 		num_retries += ctrlr->ioq[i].num_retries;
 
 	return (sysctl_handle_64(oidp, &num_retries, 0, req));
 }
 
 static int
 nvme_sysctl_num_failures(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller 	*ctrlr = arg1;
 	int64_t			num_failures = 0;
 	int			i;
 
 	num_failures = ctrlr->adminq.num_failures;
 
 	for (i = 0; i < ctrlr->num_io_queues; i++)
 		num_failures += ctrlr->ioq[i].num_failures;
 
 	return (sysctl_handle_64(oidp, &num_failures, 0, req));
 }
 
 static int
 nvme_sysctl_reset_stats(SYSCTL_HANDLER_ARGS)
 {
 	struct nvme_controller 	*ctrlr = arg1;
 	uint32_t		i, val = 0;
 
 	int error = sysctl_handle_int(oidp, &val, 0, req);
 
 	if (error)
 		return (error);
 
 	if (val != 0) {
 		nvme_qpair_reset_stats(&ctrlr->adminq);
 
 		for (i = 0; i < ctrlr->num_io_queues; i++)
 			nvme_qpair_reset_stats(&ctrlr->ioq[i]);
 	}
 
 	return (0);
 }
 
 static void
 nvme_sysctl_initialize_queue(struct nvme_qpair *qpair,
     struct sysctl_ctx_list *ctrlr_ctx, struct sysctl_oid *que_tree)
 {
 	struct sysctl_oid_list	*que_list = SYSCTL_CHILDREN(que_tree);
 
 	SYSCTL_ADD_UINT(ctrlr_ctx, que_list, OID_AUTO, "num_entries",
 	    CTLFLAG_RD, &qpair->num_entries, 0,
 	    "Number of entries in hardware queue");
 	SYSCTL_ADD_UINT(ctrlr_ctx, que_list, OID_AUTO, "num_trackers",
 	    CTLFLAG_RD, &qpair->num_trackers, 0,
 	    "Number of trackers pre-allocated for this queue pair");
 	SYSCTL_ADD_UINT(ctrlr_ctx, que_list, OID_AUTO, "sq_head",
 	    CTLFLAG_RD, &qpair->sq_head, 0,
 	    "Current head of submission queue (as observed by driver)");
 	SYSCTL_ADD_UINT(ctrlr_ctx, que_list, OID_AUTO, "sq_tail",
 	    CTLFLAG_RD, &qpair->sq_tail, 0,
 	    "Current tail of submission queue (as observed by driver)");
 	SYSCTL_ADD_UINT(ctrlr_ctx, que_list, OID_AUTO, "cq_head",
 	    CTLFLAG_RD, &qpair->cq_head, 0,
 	    "Current head of completion queue (as observed by driver)");
 
 	SYSCTL_ADD_QUAD(ctrlr_ctx, que_list, OID_AUTO, "num_cmds",
 	    CTLFLAG_RD, &qpair->num_cmds, "Number of commands submitted");
 	SYSCTL_ADD_QUAD(ctrlr_ctx, que_list, OID_AUTO, "num_intr_handler_calls",
 	    CTLFLAG_RD, &qpair->num_intr_handler_calls,
 	    "Number of times interrupt handler was invoked (will typically be "
 	    "less than number of actual interrupts generated due to "
 	    "coalescing)");
 	SYSCTL_ADD_QUAD(ctrlr_ctx, que_list, OID_AUTO, "num_retries",
 	    CTLFLAG_RD, &qpair->num_retries, "Number of commands retried");
 	SYSCTL_ADD_QUAD(ctrlr_ctx, que_list, OID_AUTO, "num_failures",
 	    CTLFLAG_RD, &qpair->num_failures,
 	    "Number of commands ending in failure after all retries");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, que_list, OID_AUTO,
 	    "dump_debug", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 	    qpair, 0, nvme_sysctl_dump_debug, "IU", "Dump debug data");
 }
 
 void
 nvme_sysctl_initialize_ctrlr(struct nvme_controller *ctrlr)
 {
 	struct sysctl_ctx_list	*ctrlr_ctx;
 	struct sysctl_oid	*ctrlr_tree, *que_tree;
 	struct sysctl_oid_list	*ctrlr_list;
 #define QUEUE_NAME_LENGTH	16
 	char			queue_name[QUEUE_NAME_LENGTH];
 	int			i;
 
 	ctrlr_ctx = device_get_sysctl_ctx(ctrlr->dev);
 	ctrlr_tree = device_get_sysctl_tree(ctrlr->dev);
 	ctrlr_list = SYSCTL_CHILDREN(ctrlr_tree);
 
 	SYSCTL_ADD_UINT(ctrlr_ctx, ctrlr_list, OID_AUTO, "num_io_queues",
 	    CTLFLAG_RD, &ctrlr->num_io_queues, 0,
 	    "Number of I/O queue pairs");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "int_coal_time", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 	    ctrlr, 0, nvme_sysctl_int_coal_time, "IU",
 	    "Interrupt coalescing timeout (in microseconds)");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "int_coal_threshold",
 	    CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, ctrlr, 0,
 	    nvme_sysctl_int_coal_threshold, "IU",
 	    "Interrupt coalescing threshold");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "timeout_period", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 	    ctrlr, 0, nvme_sysctl_timeout_period, "IU",
 	    "Timeout period (in seconds)");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "num_cmds", CTLTYPE_S64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
 	    ctrlr, 0, nvme_sysctl_num_cmds, "IU",
 	    "Number of commands submitted");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "num_intr_handler_calls",
 	    CTLTYPE_S64 | CTLFLAG_RD | CTLFLAG_MPSAFE, ctrlr, 0,
 	    nvme_sysctl_num_intr_handler_calls, "IU",
 	    "Number of times interrupt handler was invoked (will "
 	    "typically be less than number of actual interrupts "
 	    "generated due to coalescing)");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "num_retries", CTLTYPE_S64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
 	    ctrlr, 0, nvme_sysctl_num_retries, "IU",
 	    "Number of commands retried");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "num_failures", CTLTYPE_S64 | CTLFLAG_RD | CTLFLAG_MPSAFE,
 	    ctrlr, 0, nvme_sysctl_num_failures, "IU",
 	    "Number of commands ending in failure after all retries");
 
 	SYSCTL_ADD_PROC(ctrlr_ctx, ctrlr_list, OID_AUTO,
 	    "reset_stats", CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, ctrlr,
 	    0, nvme_sysctl_reset_stats, "IU", "Reset statistics to zero");
 
 	que_tree = SYSCTL_ADD_NODE(ctrlr_ctx, ctrlr_list, OID_AUTO, "adminq",
 	    CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "Admin Queue");
 
 	nvme_sysctl_initialize_queue(&ctrlr->adminq, ctrlr_ctx, que_tree);
 
 	for (i = 0; i < ctrlr->num_io_queues; i++) {
 		snprintf(queue_name, QUEUE_NAME_LENGTH, "ioq%d", i);
 		que_tree = SYSCTL_ADD_NODE(ctrlr_ctx, ctrlr_list, OID_AUTO,
 		    queue_name, CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "IO Queue");
 		nvme_sysctl_initialize_queue(&ctrlr->ioq[i], ctrlr_ctx,
 		    que_tree);
 	}
 }