mpt3sas: Set maximum transfer length per IO to 4MB for VDs

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.basappa@broadcom.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index af2099a5d3f7..71b1c58fec3b 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 d256fc0fcc98..7217218edbac 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -1909,6 +1909,14 @@ 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 */