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

From: Chaitra P B
Date: Fri Apr 22 2016 - 07:23:52 EST


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@xxxxxxxxxxxx>
---
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 32580b5..a16e7f9 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