[PATCH 2/2] smartpqi: limit transfer length to 1MB

[Yadan Fan <ydfan@suse.com>]

The smartpqi firmware will bypass the cache for any request larger
than 1MB, so we should cap the request size to avoid any
performance degradation on SLE12-SP2

This degradation is caused from d2be537c3ba3568acd79cd178327b842e60d035e,
which changed max_sectors_kb to 1280k, but the hardware is able to
work fine with it, so the true fix should be from smartpqi driver.

Reference: bsc#1025461

Signed-off-by: Yadan Fan <ydfan@suse.com>
---
 drivers/scsi/smartpqi/smartpqi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/smartpqi/smartpqi.h b/drivers/scsi/smartpqi/smartpqi.h
index b673825f46b5..9513357bd472 100644
--- a/drivers/scsi/smartpqi/smartpqi.h
+++ b/drivers/scsi/smartpqi/smartpqi.h
@@ -630,7 +630,7 @@ struct pqi_encryption_info {
 };
 
 #define PQI_MAX_OUTSTANDING_REQUESTS	((u32)~0)
-#define PQI_MAX_TRANSFER_SIZE		(4 * 1024U * 1024U)
+#define PQI_MAX_TRANSFER_SIZE		(1024U * 1024U)
 
 #define RAID_MAP_MAX_ENTRIES		1024
 
-- 
2.12.3