[SCSI] lpfc 8.3.33: Make I/O to hw queue distribution algorithm a module parameter

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

4 files changed, 22 insertions, 1 deletions

diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index d9f21fbc409..26bcbfb2a18 100644
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -684,6 +684,7 @@ struct lpfc_hba {
 #define LPFC_FCF_FOV 1          /* Fast fcf failover */
 #define LPFC_FCF_PRIORITY 2     /* Priority fcf failover */
         uint32_t cfg_fcf_failover_policy;
+        uint32_t cfg_fcp_io_sched;
         uint32_t cfg_cr_delay;
         uint32_t cfg_cr_count;
         uint32_t cfg_multi_ring_support;
diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index f7c5531d984..2ab2b9f2bff 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -3778,6 +3778,16 @@ static DEVICE_ATTR(lpfc_max_scsicmpl_time, S_IRUGO | S_IWUSR,
 LPFC_ATTR_R(ack0, 0, 0, 1, "Enable ACK0 support");
 
 /*
+# lpfc_fcp_io_sched: Determine scheduling algrithmn for issuing FCP cmds
+# range is [0,1]. Default value is 0.
+# For [0], FCP commands are issued to Work Queues ina round robin fashion.
+# For [1], FCP commands are issued to a Work Queue associated with the
+#          current CPU.
+*/
+LPFC_ATTR_RW(fcp_io_sched, 0, 0, 1, "Determine scheduling algrithmn for "
+                "issuing commands [0] - Round Robin, [1] - Current CPU");
+
+/*
 # lpfc_cr_delay & lpfc_cr_count: Default values for I/O colaesing
 # cr_delay (msec) or cr_count outstanding commands. cr_delay can take
 # value [0,63]. cr_count can take value [1,255]. Default value of cr_delay
@@ -4001,6 +4011,7 @@ struct device_attribute *lpfc_hba_attrs[] = {
         &dev_attr_lpfc_topology,
         &dev_attr_lpfc_scan_down,
         &dev_attr_lpfc_link_speed,
+        &dev_attr_lpfc_fcp_io_sched,
         &dev_attr_lpfc_cr_delay,
         &dev_attr_lpfc_cr_count,
         &dev_attr_lpfc_multi_ring_support,
@@ -4990,6 +5001,7 @@ struct fc_function_template lpfc_vport_transport_functions = {
 void
 lpfc_get_cfgparam(struct lpfc_hba *phba)
 {
+        lpfc_fcp_io_sched_init(phba, lpfc_fcp_io_sched);
         lpfc_cr_delay_init(phba, lpfc_cr_delay);
         lpfc_cr_count_init(phba, lpfc_cr_count);
         lpfc_multi_ring_support_init(phba, lpfc_multi_ring_support);
diff --git a/drivers/scsi/lpfc/lpfc_hw4.h b/drivers/scsi/lpfc/lpfc_hw4.h
index 821262d2cf7..45fbfb623ad 100644
--- a/drivers/scsi/lpfc/lpfc_hw4.h
+++ b/drivers/scsi/lpfc/lpfc_hw4.h
@@ -187,6 +187,10 @@ struct lpfc_sli_intf {
 /* Active interrupt test count */
 #define LPFC_ACT_INTR_CNT       4
 
+/* Algrithmns for scheduling FCP commands to WQs */
+#define LPFC_FCP_SCHED_ROUND_ROBIN      0
+#define LPFC_FCP_SCHED_BY_CPU           1
+
 /* Delay Multiplier constant */
 #define LPFC_DMULT_CONST       651042
 
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 0d5dab3da96..d8dbe403c37 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -7816,7 +7816,11 @@ lpfc_sli4_scmd_to_wqidx_distr(struct lpfc_hba *phba)
 {
         int i;
 
-        i = atomic_add_return(1, &phba->fcp_qidx);
+        if (phba->cfg_fcp_io_sched == LPFC_FCP_SCHED_BY_CPU)
+                i = smp_processor_id();
+        else
+                i = atomic_add_return(1, &phba->fcp_qidx);
+
         i = (i % phba->cfg_fcp_io_channel);
         return i;
 }