[SCSI] lpfc 8.2.8 v2 : Add sysfs control of target queue depth handling

Added new sysfs attribute lpfc_max_scsicmpl_time. Attribute, when enabled,
will control target queue depth based on I/O completion time.

Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 72eef7e4a891..7b17f52660b4 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -628,6 +628,7 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 
         lpfc_cmd->result = pIocbOut->iocb.un.ulpWord[4];
         lpfc_cmd->status = pIocbOut->iocb.ulpStatus;
+        atomic_dec(&pnode->cmd_pending);
 
         if (lpfc_cmd->status) {
                 if (lpfc_cmd->status == IOSTAT_LOCAL_REJECT &&
@@ -688,6 +689,29 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 
         result = cmd->result;
         sdev = cmd->device;
+        if (vport->cfg_max_scsicmpl_time &&
+           time_after(jiffies, lpfc_cmd->start_time +
+                msecs_to_jiffies(vport->cfg_max_scsicmpl_time))) {
+                spin_lock_irqsave(sdev->host->host_lock, flags);
+                if ((pnode->cmd_qdepth > atomic_read(&pnode->cmd_pending) &&
+                    (atomic_read(&pnode->cmd_pending) > LPFC_MIN_TGT_QDEPTH) &&
+                    ((cmd->cmnd[0] == READ_10) || (cmd->cmnd[0] == WRITE_10))))
+                        pnode->cmd_qdepth = atomic_read(&pnode->cmd_pending);
+
+                pnode->last_change_time = jiffies;
+                spin_unlock_irqrestore(sdev->host->host_lock, flags);
+        } else if ((pnode->cmd_qdepth < LPFC_MAX_TGT_QDEPTH) &&
+                   time_after(jiffies, pnode->last_change_time +
+                        msecs_to_jiffies(LPFC_TGTQ_INTERVAL))) {
+                spin_lock_irqsave(sdev->host->host_lock, flags);
+                pnode->cmd_qdepth += pnode->cmd_qdepth *
+                        LPFC_TGTQ_RAMPUP_PCENT / 100;
+                if (pnode->cmd_qdepth > LPFC_MAX_TGT_QDEPTH)
+                        pnode->cmd_qdepth = LPFC_MAX_TGT_QDEPTH;
+                pnode->last_change_time = jiffies;
+                spin_unlock_irqrestore(sdev->host->host_lock, flags);
+        }
+
         lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd);
         cmd->scsi_done(cmd);
 
@@ -1075,6 +1099,8 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
                 cmnd->result = ScsiResult(DID_TRANSPORT_DISRUPTED, 0);
                 goto out_fail_command;
         }
+        if (atomic_read(&ndlp->cmd_pending) >= ndlp->cmd_qdepth)
+                goto out_host_busy;
 
         lpfc_cmd = lpfc_get_scsi_buf(phba);
         if (lpfc_cmd == NULL) {
@@ -1093,6 +1119,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
         lpfc_cmd->pCmd  = cmnd;
         lpfc_cmd->rdata = rdata;
         lpfc_cmd->timeout = 0;
+        lpfc_cmd->start_time = jiffies;
         cmnd->host_scribble = (unsigned char *)lpfc_cmd;
         cmnd->scsi_done = done;
 
@@ -1102,6 +1129,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
 
         lpfc_scsi_prep_cmnd(vport, lpfc_cmd, ndlp);
 
+        atomic_inc(&ndlp->cmd_pending);
         err = lpfc_sli_issue_iocb(phba, &phba->sli.ring[psli->fcp_ring],
                                   &lpfc_cmd->cur_iocbq, SLI_IOCB_RET_IOCB);
         if (err)
@@ -1116,6 +1144,7 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
         return 0;
 
  out_host_busy_free_buf:
+        atomic_dec(&ndlp->cmd_pending);
         lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd);
         lpfc_release_scsi_buf(phba, lpfc_cmd);
  out_host_busy: