[SCSI] lpfc 8.1.1 : Added code to adjust lun queue depth to avoid target overloading

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index c422220db0ae..9ee8218404c0 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -409,6 +409,9 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
         struct lpfc_rport_data *rdata = lpfc_cmd->rdata;
         struct lpfc_nodelist *pnode = rdata->pnode;
         struct scsi_cmnd *cmd = lpfc_cmd->pCmd;
+        int result;
+        struct scsi_device *sdev, *tmp_sdev;
+        int depth = 0;
 
         lpfc_cmd->result = pIocbOut->iocb.un.ulpWord[4];
         lpfc_cmd->status = pIocbOut->iocb.ulpStatus;
@@ -460,8 +463,63 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
                                 *lp, *(lp + 3), cmd->retries, cmd->resid);
         }
 
+        result = cmd->result;
+        sdev = cmd->device;
         cmd->scsi_done(cmd);
 
+        if (!result &&
+           ((jiffies - pnode->last_ramp_up_time) >
+                LPFC_Q_RAMP_UP_INTERVAL * HZ) &&
+           ((jiffies - pnode->last_q_full_time) >
+                LPFC_Q_RAMP_UP_INTERVAL * HZ) &&
+           (phba->cfg_lun_queue_depth > sdev->queue_depth)) {
+                shost_for_each_device(tmp_sdev, sdev->host) {
+                        if (phba->cfg_lun_queue_depth > tmp_sdev->queue_depth) {
+                                if (tmp_sdev->id != sdev->id)
+                                        continue;
+                                if (tmp_sdev->ordered_tags)
+                                        scsi_adjust_queue_depth(tmp_sdev,
+                                                MSG_ORDERED_TAG,
+                                                tmp_sdev->queue_depth+1);
+                                else
+                                        scsi_adjust_queue_depth(tmp_sdev,
+                                                MSG_SIMPLE_TAG,
+                                                tmp_sdev->queue_depth+1);
+
+                                pnode->last_ramp_up_time = jiffies;
+                        }
+                }
+        }
+
+        /*
+         * Check for queue full.  If the lun is reporting queue full, then
+         * back off the lun queue depth to prevent target overloads.
+         */
+        if (result == SAM_STAT_TASK_SET_FULL) {
+                pnode->last_q_full_time = jiffies;
+
+                shost_for_each_device(tmp_sdev, sdev->host) {
+                        if (tmp_sdev->id != sdev->id)
+                                continue;
+                        depth = scsi_track_queue_full(tmp_sdev,
+                                        tmp_sdev->queue_depth - 1);
+                }
+                /*
+                 * The queue depth cannot be lowered any more.
+                 * Modify the returned error code to store
+                 * the final depth value set by
+                 * scsi_track_queue_full.
+                 */
+                if (depth == -1)
+                        depth = sdev->host->cmd_per_lun;
+
+                if (depth) {
+                        lpfc_printf_log(phba, KERN_WARNING, LOG_FCP,
+                                "%d:0711 detected queue full - lun queue depth "
+                                " adjusted to %d.\n", phba->brd_no, depth);
+                }
+        }
+
         lpfc_release_scsi_buf(phba, lpfc_cmd);
 }