diff mbox series

[04/10] qla2xxx: Fix exchange over subscription

Message ID 20221214045014.19362-5-njavali@marvell.com
State Superseded
Headers show
Series Misc. qla2xxx driver bug fixes | expand

Commit Message

Nilesh Javali Dec. 14, 2022, 4:50 a.m. UTC 
From: Quinn Tran <qutran@marvell.com>

In large environment, user can experience command timeout and
escalation of path recovery. Currently driver does not track
the number of exchanges/commands sent to FW. If there are
delay for commands at the head of the queue, then this will
create back pressure for commands at the back of the queue.

This patch would check for exchange availability before command submission.

Fixes: 89c72f4245a8 ("scsi: qla2xxx: Add IOCB resource tracking")
Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
---
 drivers/scsi/qla2xxx/qla_def.h    |  6 +++-
 drivers/scsi/qla2xxx/qla_edif.c   |  7 +++--
 drivers/scsi/qla2xxx/qla_init.c   | 13 ++++++++
 drivers/scsi/qla2xxx/qla_inline.h | 52 +++++++++++++++++++++----------
 drivers/scsi/qla2xxx/qla_iocb.c   | 28 ++++++++++-------
 drivers/scsi/qla2xxx/qla_isr.c    |  3 +-
 drivers/scsi/qla2xxx/qla_nvme.c   | 15 ++++++++-
 7 files changed, 88 insertions(+), 36 deletions(-)

Comments

Himanshu Madhani Dec. 15, 2022, 5:35 p.m. UTC | #1 
> On Dec 13, 2022, at 8:50 PM, Nilesh Javali <njavali@marvell.com> wrote:
> 
> From: Quinn Tran <qutran@marvell.com>
> 
> In large environment, user can experience command timeout and
> escalation of path recovery. Currently driver does not track
> the number of exchanges/commands sent to FW. If there are
> delay for commands at the head of the queue, then this will
> create back pressure for commands at the back of the queue.
> 
> This patch would check for exchange availability before command submission.
> 
> Fixes: 89c72f4245a8 ("scsi: qla2xxx: Add IOCB resource tracking")
> Signed-off-by: Quinn Tran <qutran@marvell.com>
> Signed-off-by: Nilesh Javali <njavali@marvell.com>
> ---
> drivers/scsi/qla2xxx/qla_def.h    |  6 +++-
> drivers/scsi/qla2xxx/qla_edif.c   |  7 +++--
> drivers/scsi/qla2xxx/qla_init.c   | 13 ++++++++
> drivers/scsi/qla2xxx/qla_inline.h | 52 +++++++++++++++++++++----------
> drivers/scsi/qla2xxx/qla_iocb.c   | 28 ++++++++++-------
> drivers/scsi/qla2xxx/qla_isr.c    |  3 +-
> drivers/scsi/qla2xxx/qla_nvme.c   | 15 ++++++++-
> 7 files changed, 88 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index a26a373be9da..cd4eb11b0707 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -660,7 +660,7 @@ enum {
> 
> struct iocb_resource {
> 	u8 res_type;
> -	u8 pad;
> +	u8  exch_cnt;
> 	u16 iocb_cnt;
> };
> 
> @@ -3721,6 +3721,10 @@ struct qla_fw_resources {
> 	u16 iocbs_limit;
> 	u16 iocbs_qp_limit;
> 	u16 iocbs_used;
> +	u16 exch_total;
> +	u16 exch_limit;
> +	u16 exch_used;
> +	u16 pad;
> };
> 
> #define QLA_IOCB_PCT_LIMIT 95
> diff --git a/drivers/scsi/qla2xxx/qla_edif.c b/drivers/scsi/qla2xxx/qla_edif.c
> index 00ccc41cef14..d17ba6275b68 100644
> --- a/drivers/scsi/qla2xxx/qla_edif.c
> +++ b/drivers/scsi/qla2xxx/qla_edif.c
> @@ -2989,9 +2989,10 @@ qla28xx_start_scsi_edif(srb_t *sp)
> 	tot_dsds = nseg;
> 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> 
> -	sp->iores.res_type = RESOURCE_INI;
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> 	sp->iores.iocb_cnt = req_cnt;
> -	if (qla_get_iocbs(sp->qpair, &sp->iores))
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores))
> 		goto queuing_error;
> 
> 	if (req->cnt < (req_cnt + 2)) {
> @@ -3185,7 +3186,7 @@ qla28xx_start_scsi_edif(srb_t *sp)
> 		mempool_free(sp->u.scmd.ct6_ctx, ha->ctx_mempool);
> 		sp->u.scmd.ct6_ctx = NULL;
> 	}
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(lock, flags);
> 
> 	return QLA_FUNCTION_FAILED;
> diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
> index 8d9ecabb1aac..fd27fb511479 100644
> --- a/drivers/scsi/qla2xxx/qla_init.c
> +++ b/drivers/scsi/qla2xxx/qla_init.c
> @@ -128,12 +128,14 @@ static void qla24xx_abort_iocb_timeout(void *data)
> 		    sp->cmd_sp)) {
> 			qpair->req->outstanding_cmds[handle] = NULL;
> 			cmdsp_found = 1;
> +			qla_put_fw_resources(qpair, &sp->cmd_sp->iores);
> 		}
> 
> 		/* removing the abort */
> 		if (qpair->req->outstanding_cmds[handle] == sp) {
> 			qpair->req->outstanding_cmds[handle] = NULL;
> 			sp_found = 1;
> +			qla_put_fw_resources(qpair, &sp->iores);
> 			break;
> 		}
> 	}
> @@ -2000,6 +2002,7 @@ qla2x00_tmf_iocb_timeout(void *data)
> 		for (h = 1; h < sp->qpair->req->num_outstanding_cmds; h++) {
> 			if (sp->qpair->req->outstanding_cmds[h] == sp) {
> 				sp->qpair->req->outstanding_cmds[h] = NULL;
> +				qla_put_fw_resources(sp->qpair, &sp->iores);
> 				break;
> 			}
> 		}
> @@ -3943,6 +3946,12 @@ void qla_init_iocb_limit(scsi_qla_host_t *vha)
> 	ha->base_qpair->fwres.iocbs_limit = limit;
> 	ha->base_qpair->fwres.iocbs_qp_limit = limit / num_qps;
> 	ha->base_qpair->fwres.iocbs_used = 0;
> +
> +	ha->base_qpair->fwres.exch_total = ha->orig_fw_xcb_count;
> +	ha->base_qpair->fwres.exch_limit = (ha->orig_fw_xcb_count *
> +					    QLA_IOCB_PCT_LIMIT) / 100;
> +	ha->base_qpair->fwres.exch_used  = 0;
> +
> 	for (i = 0; i < ha->max_qpairs; i++) {
> 		if (ha->queue_pair_map[i])  {
> 			ha->queue_pair_map[i]->fwres.iocbs_total =
> @@ -3951,6 +3960,10 @@ void qla_init_iocb_limit(scsi_qla_host_t *vha)
> 			ha->queue_pair_map[i]->fwres.iocbs_qp_limit =
> 				limit / num_qps;
> 			ha->queue_pair_map[i]->fwres.iocbs_used = 0;
> +			ha->queue_pair_map[i]->fwres.exch_total = ha->orig_fw_xcb_count;
> +			ha->queue_pair_map[i]->fwres.exch_limit =
> +				(ha->orig_fw_xcb_count * QLA_IOCB_PCT_LIMIT) / 100;
> +			ha->queue_pair_map[i]->fwres.exch_used = 0;
> 		}
> 	}
> }
> diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h
> index 5185dc5daf80..2d5a275d8b00 100644
> --- a/drivers/scsi/qla2xxx/qla_inline.h
> +++ b/drivers/scsi/qla2xxx/qla_inline.h
> @@ -380,13 +380,16 @@ qla2xxx_get_fc4_priority(struct scsi_qla_host *vha)
> 
> enum {
> 	RESOURCE_NONE,
> -	RESOURCE_INI,
> +	RESOURCE_IOCB  = BIT_0,
> +	RESOURCE_EXCH = BIT_1,  /* exchange */
> +	RESOURCE_FORCE = BIT_2,
> };
> 
> static inline int
> -qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> +qla_get_fw_resources(struct qla_qpair *qp, struct iocb_resource *iores)
> {
> 	u16 iocbs_used, i;
> +	u16 exch_used;
> 	struct qla_hw_data *ha = qp->vha->hw;
> 
> 	if (!ql2xenforce_iocb_limit) {
> @@ -394,10 +397,7 @@ qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> 		return 0;
> 	}
> 
> -	if ((iores->iocb_cnt + qp->fwres.iocbs_used) < qp->fwres.iocbs_qp_limit) {
> -		qp->fwres.iocbs_used += iores->iocb_cnt;
> -		return 0;
> -	} else {
> +	if ((iores->iocb_cnt + qp->fwres.iocbs_used) >= qp->fwres.iocbs_qp_limit) {
> 		/* no need to acquire qpair lock. It's just rough calculation */
> 		iocbs_used = ha->base_qpair->fwres.iocbs_used;
> 		for (i = 0; i < ha->max_qpairs; i++) {
> @@ -405,30 +405,48 @@ qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> 				iocbs_used += ha->queue_pair_map[i]->fwres.iocbs_used;
> 		}
> 
> -		if ((iores->iocb_cnt + iocbs_used) < qp->fwres.iocbs_limit) {
> -			qp->fwres.iocbs_used += iores->iocb_cnt;
> -			return 0;
> -		} else {
> +		if ((iores->iocb_cnt + iocbs_used) >= qp->fwres.iocbs_limit) {
> +			iores->res_type = RESOURCE_NONE;
> +			return -ENOSPC;
> +		}
> +	}
> +
> +	if (iores->res_type & RESOURCE_EXCH) {
> +		exch_used = ha->base_qpair->fwres.exch_used;
> +		for (i = 0; i < ha->max_qpairs; i++) {
> +			if (ha->queue_pair_map[i])
> +				exch_used += ha->queue_pair_map[i]->fwres.exch_used;
> +		}
> +
> +		if ((exch_used + iores->exch_cnt) >= qp->fwres.exch_limit) {
> 			iores->res_type = RESOURCE_NONE;
> 			return -ENOSPC;
> 		}
> 	}
> +	qp->fwres.iocbs_used += iores->iocb_cnt;
> +	qp->fwres.exch_used += iores->exch_cnt;
> +	return 0;
> }
> 
> static inline void
> -qla_put_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
> +qla_put_fw_resources(struct qla_qpair *qp, struct iocb_resource *iores)
> {
> -	switch (iores->res_type) {
> -	case RESOURCE_NONE:
> -		break;
> -	default:
> +	if (iores->res_type & RESOURCE_IOCB) {
> 		if (qp->fwres.iocbs_used >= iores->iocb_cnt) {
> 			qp->fwres.iocbs_used -= iores->iocb_cnt;
> 		} else {
> -			// should not happen
> +			/* should not happen */
> 			qp->fwres.iocbs_used = 0;
> 		}
> -		break;
> +	}
> +
> +	if (iores->res_type & RESOURCE_EXCH) {
> +		if (qp->fwres.exch_used >= iores->exch_cnt) {
> +			qp->fwres.exch_used -= iores->exch_cnt;
> +		} else {
> +			/* should not happen */
> +			qp->fwres.exch_used = 0;
> +		}
> 	}
> 	iores->res_type = RESOURCE_NONE;
> }
> diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
> index 42ce4e1fe744..399ec8da2d73 100644
> --- a/drivers/scsi/qla2xxx/qla_iocb.c
> +++ b/drivers/scsi/qla2xxx/qla_iocb.c
> @@ -1589,9 +1589,10 @@ qla24xx_start_scsi(srb_t *sp)
> 	tot_dsds = nseg;
> 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> 
> -	sp->iores.res_type = RESOURCE_INI;
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> 	sp->iores.iocb_cnt = req_cnt;
> -	if (qla_get_iocbs(sp->qpair, &sp->iores))
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores))
> 		goto queuing_error;
> 
> 	if (req->cnt < (req_cnt + 2)) {
> @@ -1678,7 +1679,7 @@ qla24xx_start_scsi(srb_t *sp)
> 	if (tot_dsds)
> 		scsi_dma_unmap(cmd);
> 
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
> 
> 	return QLA_FUNCTION_FAILED;
> @@ -1793,9 +1794,10 @@ qla24xx_dif_start_scsi(srb_t *sp)
> 	tot_prot_dsds = nseg;
> 	tot_dsds += nseg;
> 
> -	sp->iores.res_type = RESOURCE_INI;
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> 	sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> -	if (qla_get_iocbs(sp->qpair, &sp->iores))
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores))
> 		goto queuing_error;
> 
> 	if (req->cnt < (req_cnt + 2)) {
> @@ -1883,7 +1885,7 @@ qla24xx_dif_start_scsi(srb_t *sp)
> 	}
> 	/* Cleanup will be performed by the caller (queuecommand) */
> 
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
> 
> 	return QLA_FUNCTION_FAILED;
> @@ -1952,9 +1954,10 @@ qla2xxx_start_scsi_mq(srb_t *sp)
> 	tot_dsds = nseg;
> 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> 
> -	sp->iores.res_type = RESOURCE_INI;
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> 	sp->iores.iocb_cnt = req_cnt;
> -	if (qla_get_iocbs(sp->qpair, &sp->iores))
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores))
> 		goto queuing_error;
> 
> 	if (req->cnt < (req_cnt + 2)) {
> @@ -2041,7 +2044,7 @@ qla2xxx_start_scsi_mq(srb_t *sp)
> 	if (tot_dsds)
> 		scsi_dma_unmap(cmd);
> 
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
> 
> 	return QLA_FUNCTION_FAILED;
> @@ -2171,9 +2174,10 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
> 	tot_prot_dsds = nseg;
> 	tot_dsds += nseg;
> 
> -	sp->iores.res_type = RESOURCE_INI;
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> 	sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> -	if (qla_get_iocbs(sp->qpair, &sp->iores))
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores))
> 		goto queuing_error;
> 
> 	if (req->cnt < (req_cnt + 2)) {
> @@ -2260,7 +2264,7 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
> 	}
> 	/* Cleanup will be performed by the caller (queuecommand) */
> 
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
> 
> 	return QLA_FUNCTION_FAILED;
> diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
> index e19fde304e5c..42d3d2de3d31 100644
> --- a/drivers/scsi/qla2xxx/qla_isr.c
> +++ b/drivers/scsi/qla2xxx/qla_isr.c
> @@ -3197,7 +3197,7 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
> 		}
> 		return;
> 	}
> -	qla_put_iocbs(sp->qpair, &sp->iores);
> +	qla_put_fw_resources(sp->qpair, &sp->iores);
> 
> 	if (sp->cmd_type != TYPE_SRB) {
> 		req->outstanding_cmds[handle] = NULL;
> @@ -3618,7 +3618,6 @@ qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
> 	default:
> 		sp = qla2x00_get_sp_from_handle(vha, func, req, pkt);
> 		if (sp) {
> -			qla_put_iocbs(sp->qpair, &sp->iores);
> 			sp->done(sp, res);
> 			return 0;
> 		}
> diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
> index 8927ddc5e69c..c57e02a35521 100644
> --- a/drivers/scsi/qla2xxx/qla_nvme.c
> +++ b/drivers/scsi/qla2xxx/qla_nvme.c
> @@ -428,13 +428,24 @@ static inline int qla2x00_start_nvme_mq(srb_t *sp)
> 		goto queuing_error;
> 	}
> 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
> +
> +	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
> +	sp->iores.exch_cnt = 1;
> +	sp->iores.iocb_cnt = req_cnt;
> +	if (qla_get_fw_resources(sp->qpair, &sp->iores)) {
> +		rval = -EBUSY;
> +		goto queuing_error;
> +	}
> +
> 	if (req->cnt < (req_cnt + 2)) {
> 		if (IS_SHADOW_REG_CAPABLE(ha)) {
> 			cnt = *req->out_ptr;
> 		} else {
> 			cnt = rd_reg_dword_relaxed(req->req_q_out);
> -			if (qla2x00_check_reg16_for_disconnect(vha, cnt))
> +			if (qla2x00_check_reg16_for_disconnect(vha, cnt)) {
> +				rval = -EBUSY;
> 				goto queuing_error;
> +			}
> 		}
> 
> 		if (req->ring_index < cnt)
> @@ -583,6 +594,8 @@ static inline int qla2x00_start_nvme_mq(srb_t *sp)
> 		qla24xx_process_response_queue(vha, rsp);
> 
> queuing_error:
> +	if (rval)
> +		qla_put_fw_resources(sp->qpair, &sp->iores);
> 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
> 
> 	return rval;
> -- 
> 2.19.0.rc0
> 

Looks Good.

Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
diff mbox series

Patch

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index a26a373be9da..cd4eb11b0707 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -660,7 +660,7 @@  enum {
 
 struct iocb_resource {
 	u8 res_type;
-	u8 pad;
+	u8  exch_cnt;
 	u16 iocb_cnt;
 };
 
@@ -3721,6 +3721,10 @@  struct qla_fw_resources {
 	u16 iocbs_limit;
 	u16 iocbs_qp_limit;
 	u16 iocbs_used;
+	u16 exch_total;
+	u16 exch_limit;
+	u16 exch_used;
+	u16 pad;
 };
 
 #define QLA_IOCB_PCT_LIMIT 95
diff --git a/drivers/scsi/qla2xxx/qla_edif.c b/drivers/scsi/qla2xxx/qla_edif.c
index 00ccc41cef14..d17ba6275b68 100644
--- a/drivers/scsi/qla2xxx/qla_edif.c
+++ b/drivers/scsi/qla2xxx/qla_edif.c
@@ -2989,9 +2989,10 @@  qla28xx_start_scsi_edif(srb_t *sp)
 	tot_dsds = nseg;
 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
 
-	sp->iores.res_type = RESOURCE_INI;
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
 	sp->iores.iocb_cnt = req_cnt;
-	if (qla_get_iocbs(sp->qpair, &sp->iores))
+	if (qla_get_fw_resources(sp->qpair, &sp->iores))
 		goto queuing_error;
 
 	if (req->cnt < (req_cnt + 2)) {
@@ -3185,7 +3186,7 @@  qla28xx_start_scsi_edif(srb_t *sp)
 		mempool_free(sp->u.scmd.ct6_ctx, ha->ctx_mempool);
 		sp->u.scmd.ct6_ctx = NULL;
 	}
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(lock, flags);
 
 	return QLA_FUNCTION_FAILED;
diff --git a/drivers/scsi/qla2xxx/qla_init.c b/drivers/scsi/qla2xxx/qla_init.c
index 8d9ecabb1aac..fd27fb511479 100644
--- a/drivers/scsi/qla2xxx/qla_init.c
+++ b/drivers/scsi/qla2xxx/qla_init.c
@@ -128,12 +128,14 @@  static void qla24xx_abort_iocb_timeout(void *data)
 		    sp->cmd_sp)) {
 			qpair->req->outstanding_cmds[handle] = NULL;
 			cmdsp_found = 1;
+			qla_put_fw_resources(qpair, &sp->cmd_sp->iores);
 		}
 
 		/* removing the abort */
 		if (qpair->req->outstanding_cmds[handle] == sp) {
 			qpair->req->outstanding_cmds[handle] = NULL;
 			sp_found = 1;
+			qla_put_fw_resources(qpair, &sp->iores);
 			break;
 		}
 	}
@@ -2000,6 +2002,7 @@  qla2x00_tmf_iocb_timeout(void *data)
 		for (h = 1; h < sp->qpair->req->num_outstanding_cmds; h++) {
 			if (sp->qpair->req->outstanding_cmds[h] == sp) {
 				sp->qpair->req->outstanding_cmds[h] = NULL;
+				qla_put_fw_resources(sp->qpair, &sp->iores);
 				break;
 			}
 		}
@@ -3943,6 +3946,12 @@  void qla_init_iocb_limit(scsi_qla_host_t *vha)
 	ha->base_qpair->fwres.iocbs_limit = limit;
 	ha->base_qpair->fwres.iocbs_qp_limit = limit / num_qps;
 	ha->base_qpair->fwres.iocbs_used = 0;
+
+	ha->base_qpair->fwres.exch_total = ha->orig_fw_xcb_count;
+	ha->base_qpair->fwres.exch_limit = (ha->orig_fw_xcb_count *
+					    QLA_IOCB_PCT_LIMIT) / 100;
+	ha->base_qpair->fwres.exch_used  = 0;
+
 	for (i = 0; i < ha->max_qpairs; i++) {
 		if (ha->queue_pair_map[i])  {
 			ha->queue_pair_map[i]->fwres.iocbs_total =
@@ -3951,6 +3960,10 @@  void qla_init_iocb_limit(scsi_qla_host_t *vha)
 			ha->queue_pair_map[i]->fwres.iocbs_qp_limit =
 				limit / num_qps;
 			ha->queue_pair_map[i]->fwres.iocbs_used = 0;
+			ha->queue_pair_map[i]->fwres.exch_total = ha->orig_fw_xcb_count;
+			ha->queue_pair_map[i]->fwres.exch_limit =
+				(ha->orig_fw_xcb_count * QLA_IOCB_PCT_LIMIT) / 100;
+			ha->queue_pair_map[i]->fwres.exch_used = 0;
 		}
 	}
 }
diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h
index 5185dc5daf80..2d5a275d8b00 100644
--- a/drivers/scsi/qla2xxx/qla_inline.h
+++ b/drivers/scsi/qla2xxx/qla_inline.h
@@ -380,13 +380,16 @@  qla2xxx_get_fc4_priority(struct scsi_qla_host *vha)
 
 enum {
 	RESOURCE_NONE,
-	RESOURCE_INI,
+	RESOURCE_IOCB  = BIT_0,
+	RESOURCE_EXCH = BIT_1,  /* exchange */
+	RESOURCE_FORCE = BIT_2,
 };
 
 static inline int
-qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
+qla_get_fw_resources(struct qla_qpair *qp, struct iocb_resource *iores)
 {
 	u16 iocbs_used, i;
+	u16 exch_used;
 	struct qla_hw_data *ha = qp->vha->hw;
 
 	if (!ql2xenforce_iocb_limit) {
@@ -394,10 +397,7 @@  qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
 		return 0;
 	}
 
-	if ((iores->iocb_cnt + qp->fwres.iocbs_used) < qp->fwres.iocbs_qp_limit) {
-		qp->fwres.iocbs_used += iores->iocb_cnt;
-		return 0;
-	} else {
+	if ((iores->iocb_cnt + qp->fwres.iocbs_used) >= qp->fwres.iocbs_qp_limit) {
 		/* no need to acquire qpair lock. It's just rough calculation */
 		iocbs_used = ha->base_qpair->fwres.iocbs_used;
 		for (i = 0; i < ha->max_qpairs; i++) {
@@ -405,30 +405,48 @@  qla_get_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
 				iocbs_used += ha->queue_pair_map[i]->fwres.iocbs_used;
 		}
 
-		if ((iores->iocb_cnt + iocbs_used) < qp->fwres.iocbs_limit) {
-			qp->fwres.iocbs_used += iores->iocb_cnt;
-			return 0;
-		} else {
+		if ((iores->iocb_cnt + iocbs_used) >= qp->fwres.iocbs_limit) {
+			iores->res_type = RESOURCE_NONE;
+			return -ENOSPC;
+		}
+	}
+
+	if (iores->res_type & RESOURCE_EXCH) {
+		exch_used = ha->base_qpair->fwres.exch_used;
+		for (i = 0; i < ha->max_qpairs; i++) {
+			if (ha->queue_pair_map[i])
+				exch_used += ha->queue_pair_map[i]->fwres.exch_used;
+		}
+
+		if ((exch_used + iores->exch_cnt) >= qp->fwres.exch_limit) {
 			iores->res_type = RESOURCE_NONE;
 			return -ENOSPC;
 		}
 	}
+	qp->fwres.iocbs_used += iores->iocb_cnt;
+	qp->fwres.exch_used += iores->exch_cnt;
+	return 0;
 }
 
 static inline void
-qla_put_iocbs(struct qla_qpair *qp, struct iocb_resource *iores)
+qla_put_fw_resources(struct qla_qpair *qp, struct iocb_resource *iores)
 {
-	switch (iores->res_type) {
-	case RESOURCE_NONE:
-		break;
-	default:
+	if (iores->res_type & RESOURCE_IOCB) {
 		if (qp->fwres.iocbs_used >= iores->iocb_cnt) {
 			qp->fwres.iocbs_used -= iores->iocb_cnt;
 		} else {
-			// should not happen
+			/* should not happen */
 			qp->fwres.iocbs_used = 0;
 		}
-		break;
+	}
+
+	if (iores->res_type & RESOURCE_EXCH) {
+		if (qp->fwres.exch_used >= iores->exch_cnt) {
+			qp->fwres.exch_used -= iores->exch_cnt;
+		} else {
+			/* should not happen */
+			qp->fwres.exch_used = 0;
+		}
 	}
 	iores->res_type = RESOURCE_NONE;
 }
diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 42ce4e1fe744..399ec8da2d73 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -1589,9 +1589,10 @@  qla24xx_start_scsi(srb_t *sp)
 	tot_dsds = nseg;
 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
 
-	sp->iores.res_type = RESOURCE_INI;
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
 	sp->iores.iocb_cnt = req_cnt;
-	if (qla_get_iocbs(sp->qpair, &sp->iores))
+	if (qla_get_fw_resources(sp->qpair, &sp->iores))
 		goto queuing_error;
 
 	if (req->cnt < (req_cnt + 2)) {
@@ -1678,7 +1679,7 @@  qla24xx_start_scsi(srb_t *sp)
 	if (tot_dsds)
 		scsi_dma_unmap(cmd);
 
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
 	return QLA_FUNCTION_FAILED;
@@ -1793,9 +1794,10 @@  qla24xx_dif_start_scsi(srb_t *sp)
 	tot_prot_dsds = nseg;
 	tot_dsds += nseg;
 
-	sp->iores.res_type = RESOURCE_INI;
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
 	sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
-	if (qla_get_iocbs(sp->qpair, &sp->iores))
+	if (qla_get_fw_resources(sp->qpair, &sp->iores))
 		goto queuing_error;
 
 	if (req->cnt < (req_cnt + 2)) {
@@ -1883,7 +1885,7 @@  qla24xx_dif_start_scsi(srb_t *sp)
 	}
 	/* Cleanup will be performed by the caller (queuecommand) */
 
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
 	return QLA_FUNCTION_FAILED;
@@ -1952,9 +1954,10 @@  qla2xxx_start_scsi_mq(srb_t *sp)
 	tot_dsds = nseg;
 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
 
-	sp->iores.res_type = RESOURCE_INI;
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
 	sp->iores.iocb_cnt = req_cnt;
-	if (qla_get_iocbs(sp->qpair, &sp->iores))
+	if (qla_get_fw_resources(sp->qpair, &sp->iores))
 		goto queuing_error;
 
 	if (req->cnt < (req_cnt + 2)) {
@@ -2041,7 +2044,7 @@  qla2xxx_start_scsi_mq(srb_t *sp)
 	if (tot_dsds)
 		scsi_dma_unmap(cmd);
 
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
 
 	return QLA_FUNCTION_FAILED;
@@ -2171,9 +2174,10 @@  qla2xxx_dif_start_scsi_mq(srb_t *sp)
 	tot_prot_dsds = nseg;
 	tot_dsds += nseg;
 
-	sp->iores.res_type = RESOURCE_INI;
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
 	sp->iores.iocb_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
-	if (qla_get_iocbs(sp->qpair, &sp->iores))
+	if (qla_get_fw_resources(sp->qpair, &sp->iores))
 		goto queuing_error;
 
 	if (req->cnt < (req_cnt + 2)) {
@@ -2260,7 +2264,7 @@  qla2xxx_dif_start_scsi_mq(srb_t *sp)
 	}
 	/* Cleanup will be performed by the caller (queuecommand) */
 
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
 
 	return QLA_FUNCTION_FAILED;
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index e19fde304e5c..42d3d2de3d31 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -3197,7 +3197,7 @@  qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
 		}
 		return;
 	}
-	qla_put_iocbs(sp->qpair, &sp->iores);
+	qla_put_fw_resources(sp->qpair, &sp->iores);
 
 	if (sp->cmd_type != TYPE_SRB) {
 		req->outstanding_cmds[handle] = NULL;
@@ -3618,7 +3618,6 @@  qla2x00_error_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, sts_entry_t *pkt)
 	default:
 		sp = qla2x00_get_sp_from_handle(vha, func, req, pkt);
 		if (sp) {
-			qla_put_iocbs(sp->qpair, &sp->iores);
 			sp->done(sp, res);
 			return 0;
 		}
diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
index 8927ddc5e69c..c57e02a35521 100644
--- a/drivers/scsi/qla2xxx/qla_nvme.c
+++ b/drivers/scsi/qla2xxx/qla_nvme.c
@@ -428,13 +428,24 @@  static inline int qla2x00_start_nvme_mq(srb_t *sp)
 		goto queuing_error;
 	}
 	req_cnt = qla24xx_calc_iocbs(vha, tot_dsds);
+
+	sp->iores.res_type = RESOURCE_IOCB | RESOURCE_EXCH;
+	sp->iores.exch_cnt = 1;
+	sp->iores.iocb_cnt = req_cnt;
+	if (qla_get_fw_resources(sp->qpair, &sp->iores)) {
+		rval = -EBUSY;
+		goto queuing_error;
+	}
+
 	if (req->cnt < (req_cnt + 2)) {
 		if (IS_SHADOW_REG_CAPABLE(ha)) {
 			cnt = *req->out_ptr;
 		} else {
 			cnt = rd_reg_dword_relaxed(req->req_q_out);
-			if (qla2x00_check_reg16_for_disconnect(vha, cnt))
+			if (qla2x00_check_reg16_for_disconnect(vha, cnt)) {
+				rval = -EBUSY;
 				goto queuing_error;
+			}
 		}
 
 		if (req->ring_index < cnt)
@@ -583,6 +594,8 @@  static inline int qla2x00_start_nvme_mq(srb_t *sp)
 		qla24xx_process_response_queue(vha, rsp);
 
 queuing_error:
+	if (rval)
+		qla_put_fw_resources(sp->qpair, &sp->iores);
 	spin_unlock_irqrestore(&qpair->qp_lock, flags);
 
 	return rval;