[PATCH 5/6] mpt3sas: Set maximum transfer length per IO to 4MB for VDs

[Chaitra P B]

Set maximum transfer length per IO on RAID volumes
to 4MB by setting VD's queue's max_sector to 8192.

Signed-off-by: Chaitra P B <chaitra.basa...@broadcom.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.h  | 2 ++
 drivers/scsi/mpt3sas/mpt3sas_scsih.c | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h 
b/drivers/scsi/mpt3sas/mpt3sas_base.h
index aa918aa..e1befba 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -112,6 +112,8 @@
 #define MPT3SAS_SAS_QUEUE_DEPTH                254
 #define MPT3SAS_RAID_QUEUE_DEPTH       128
 
+#define MPT3SAS_RAID_MAX_SECTORS       8192
+
 #define MPT_NAME_LENGTH                        32      /* generic length of 
strings */
 #define MPT_STRING_LENGTH              64
 
diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c 
b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 0fea937..abd8717 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -1911,6 +1911,14 @@ scsih_slave_configure(struct scsi_device *sdev)
                            (unsigned long long)raid_device->wwid,
                            raid_device->num_pds, ds);
 
+               if (shost->max_sectors > MPT3SAS_RAID_MAX_SECTORS) {
+                       blk_queue_max_hw_sectors(sdev->request_queue,
+                                               MPT3SAS_RAID_MAX_SECTORS);
+                       sdev_printk(KERN_INFO, sdev,
+                                       "Set queue's max_sector to: %u\n",
+                                               MPT3SAS_RAID_MAX_SECTORS);
+               }
+
                scsih_change_queue_depth(sdev, qdepth);
 
                /* raid transport support */
-- 
1.8.3.1

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