scsi: qla2xxx: Fix exchange oversubscription

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>

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index a26a373be9da302290c36fed9fb26f5881459769..cd4eb11b07079a2e2d097503761c0903c6ba2fd2 100644 (file)
--- 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 e4240aae5f9e3325fab8ebaf5448cbb5dd36bce5..53186a14596294984797f75a389e1a1821f51c75 100644 (file)
--- 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 @@ queuing_error:
                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 8d9ecabb1aac1b3f7000358287c8279e1af3b8ff..fd27fb511479647d3f302ccf9722294c19759ebc 100644 (file)
--- 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 5185dc5daf80d47cbf279faf95ce0e0a777603f8..2d5a275d8b00078a51597227554e7dd8c4320e0f 100644 (file)
--- 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 42ce4e1fe7441fe8299e63a5ebaaeaebfe22992e..399ec8da2d73c3354cde61e96036f490efda6142 100644 (file)
--- 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 @@ queuing_error:
        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 @@ queuing_error:
        }
        /* 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 @@ queuing_error:
        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 @@ queuing_error:
        }
        /* 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 e19fde304e5c6891b44db73496f9fefe69643398..42d3d2de3d31fa8b68bc74f4b951b8b06754e2a8 100644 (file)
--- 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 8927ddc5e69cdf235c49d1fbf39c570d0f09e5c4..c57e02a3552194c4f985dfd3e304e12714b39d37 100644 (file)
--- 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;