[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, 44 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 21397f37010d..343b0b36ed22 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -2297,6 +2297,48 @@ LPFC_VPORT_ATTR_RW(use_adisc, 0, 0, 1,
                    "Use ADISC on rediscovery to authenticate FCP devices");
 
 /*
+# lpfc_max_scsicmpl_time: Use scsi command completion time to control I/O queue
+# depth. Default value is 0. When the value of this parameter is zero the
+# SCSI command completion time is not used for controlling I/O queue depth. When
+# the parameter is set to a non-zero value, the I/O queue depth is controlled
+# to limit the I/O completion time to the parameter value.
+# The value is set in milliseconds.
+*/
+static int lpfc_max_scsicmpl_time;
+module_param(lpfc_max_scsicmpl_time, int, 0);
+MODULE_PARM_DESC(lpfc_max_scsicmpl_time,
+        "Use command completion time to control queue depth");
+lpfc_vport_param_show(max_scsicmpl_time);
+lpfc_vport_param_init(max_scsicmpl_time, 0, 0, 60000);
+static int
+lpfc_max_scsicmpl_time_set(struct lpfc_vport *vport, int val)
+{
+        struct Scsi_Host *shost = lpfc_shost_from_vport(vport);
+        struct lpfc_nodelist *ndlp, *next_ndlp;
+
+        if (val == vport->cfg_max_scsicmpl_time)
+                return 0;
+        if ((val < 0) || (val > 60000))
+                return -EINVAL;
+        vport->cfg_max_scsicmpl_time = val;
+
+        spin_lock_irq(shost->host_lock);
+        list_for_each_entry_safe(ndlp, next_ndlp, &vport->fc_nodes, nlp_listp) {
+                if (!NLP_CHK_NODE_ACT(ndlp))
+                        continue;
+                if (ndlp->nlp_state == NLP_STE_UNUSED_NODE)
+                        continue;
+                ndlp->cmd_qdepth = LPFC_MAX_TGT_QDEPTH;
+        }
+        spin_unlock_irq(shost->host_lock);
+        return 0;
+}
+lpfc_vport_param_store(max_scsicmpl_time);
+static DEVICE_ATTR(lpfc_max_scsicmpl_time, S_IRUGO | S_IWUSR,
+                   lpfc_max_scsicmpl_time_show,
+                   lpfc_max_scsicmpl_time_store);
+
+/*
 # lpfc_ack0: Use ACK0, instead of ACK1 for class 2 acknowledgement. Value
 # range is [0,1]. Default value is 0.
 */
@@ -2459,6 +2501,7 @@ struct device_attribute *lpfc_hba_attrs[] = {
         &dev_attr_lpfc_enable_hba_reset,
         &dev_attr_lpfc_enable_hba_heartbeat,
         &dev_attr_lpfc_sg_seg_cnt,
+        &dev_attr_lpfc_max_scsicmpl_time,
         NULL,
 };
 
@@ -3580,6 +3623,7 @@ lpfc_get_vport_cfgparam(struct lpfc_vport *vport)
         lpfc_restrict_login_init(vport, lpfc_restrict_login);
         lpfc_fcp_class_init(vport, lpfc_fcp_class);
         lpfc_use_adisc_init(vport, lpfc_use_adisc);
+        lpfc_max_scsicmpl_time_init(vport, lpfc_max_scsicmpl_time);
         lpfc_fdmi_on_init(vport, lpfc_fdmi_on);
         lpfc_discovery_threads_init(vport, lpfc_discovery_threads);
         lpfc_max_luns_init(vport, lpfc_max_luns);