scsi: lpfc: small sg cnt cleanup
The logic for sg_seg_cnt is a bit convoluted. This patch tries to clean
up a couple of areas, especially around the +2 and +1 logic.
This patch:
- Cleans up the lpfc_sg_seg_cnt attribute to specify a real minimum
rather than making the minimum be whatever the default is.
- Removes the hardcoding of +2 (for the number of elements we use in a
sgl for cmd iu and rsp iu) and +1 (an additional entry to compensate
for nvme's reduction of io size based on a possible partial page)
logic in sg list initialization. In the case where the +1 logic is
referenced in host and target io checks, use the values set in the
transport template as that value was properly set.
There can certainly be more done in this area and it will be addressed
in combined host/target driver effort.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index 46a89bd..dd2191c 100644
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -55,6 +55,7 @@ struct lpfc_sli2_slim;
#define LPFC_MAX_SG_SLI4_SEG_CNT_DIF 128 /* sg element count per scsi cmnd */
#define LPFC_MAX_SG_SEG_CNT_DIF 512 /* sg element count per scsi cmnd */
#define LPFC_MAX_SG_SEG_CNT 4096 /* sg element count per scsi cmnd */
+#define LPFC_MIN_SG_SEG_CNT 32 /* sg element count per scsi cmnd */
#define LPFC_MAX_SGL_SEG_CNT 512 /* SGL element count per scsi cmnd */
#define LPFC_MAX_BPL_SEG_CNT 4096 /* BPL element count per scsi cmnd */
#define LPFC_MAX_NVME_SEG_CNT 256 /* max SGL element cnt per NVME cmnd */