lpfc: Utilize embedded CDB logic to minimize IO latency
Pass cmd iu payloads inline to adapter job structure rather than as
separate dma buffers.
Signed-off-by: Dick Kennedy <dick.kennedy@avagotech.com>
Signed-off-by: James Smart <james.smart@avagotech.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index f57d02c..f0d0852 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -7264,8 +7264,15 @@
phba->sli4_hba.fcp_cq[idx] = qdesc;
/* Create Fast Path FCP WQs */
- qdesc = lpfc_sli4_queue_alloc(phba, phba->sli4_hba.wq_esize,
- phba->sli4_hba.wq_ecount);
+ if (phba->fcp_embed_io) {
+ qdesc = lpfc_sli4_queue_alloc(phba,
+ LPFC_WQE128_SIZE,
+ LPFC_WQE128_DEF_COUNT);
+ } else {
+ qdesc = lpfc_sli4_queue_alloc(phba,
+ phba->sli4_hba.wq_esize,
+ phba->sli4_hba.wq_ecount);
+ }
if (!qdesc) {
lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
"0503 Failed allocate fast-path FCP "
@@ -9510,6 +9517,15 @@
if (sli4_params->sge_supp_len > LPFC_MAX_SGE_SIZE)
sli4_params->sge_supp_len = LPFC_MAX_SGE_SIZE;
+ /*
+ * Issue IOs with CDB embedded in WQE to minimized the number
+ * of DMAs the firmware has to do. Setting this to 1 also forces
+ * the driver to use 128 bytes WQEs for FCP IOs.
+ */
+ if (bf_get(cfg_ext_embed_cb, mbx_sli4_parameters))
+ phba->fcp_embed_io = 1;
+ else
+ phba->fcp_embed_io = 0;
return 0;
}