[PATCH 5.15 185/567] scsi: qla2xxx: Fix exchange oversubscription

7 Mar 2023

From: Quinn Tran qutran@marvell.com
[ Upstream commit 41e5afe51f75f2858f5563145348f6c26d307b8f ]
In large environment, it is possible to experience command timeout and
escalation of path recovery. Currently the driver does not track the number
of exchanges/commands sent to FW. If there is a delay for commands at the
head of the queue, then this will create back pressure for commands at the
back of the queue.
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
Reviewed-by: Himanshu Madhani himanshu.madhani@oracle.com
Signed-off-by: Martin K. Petersen martin.petersen@oracle.com
Signed-off-by: Sasha Levin sashal@kernel.org
---
 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 307ffdfe048be..5b499b0e2c867 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -655,7 +655,7 @@ enum {
struct iocb_resource {
    u8 res_type;
-	u8 pad;
+	u8  exch_cnt;
    u16 iocb_cnt;
 };
@@ -3707,6 +3707,10 @@ 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 a7e2118b3a841..f81cf85dcdc7b 100644
--- a/drivers/scsi/qla2xxx/qla_edif.c
+++ b/drivers/scsi/qla2xxx/qla_edif.c
@@ -2899,9 +2899,10 @@ 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)) {
@@ -3095,7 +3096,7 @@ 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 30798ab84db91..b61aa5a1a21dc 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;
    	}
    }
@@ -2002,6 +2004,7 @@ 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;
    		}
    	}
@@ -3945,6 +3948,12 @@ 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 =
@@ -3953,6 +3962,10 @@ 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 5185dc5daf80d..2d5a275d8b000 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 42ce4e1fe7441..399ec8da2d73c 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 59f5918dca95f..c545f39362ffc 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -3184,7 +3184,7 @@ 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;
@@ -3605,7 +3605,6 @@ 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 3e167dc4eec72..b66e19a8545c9 100644
--- a/drivers/scsi/qla2xxx/qla_nvme.c
+++ b/drivers/scsi/qla2xxx/qla_nvme.c
@@ -438,13 +438,24 @@ 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)
@@ -589,6 +600,8 @@ static inline int qla2x00_start_nvme_mq(srb_t *sp)
    wrt_reg_dword(req->req_q_in, req->ring_index);
queuing_error:
+	if (rval)
+		qla_put_fw_resources(sp->qpair, &sp->iores);
    spin_unlock_irqrestore(&qpair->qp_lock, flags);
return rval;
-- 
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[PATCH 5.15 185/567] scsi: qla2xxx: Fix exchange oversubscription