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

Yadan Fan
2017-06-22T09:58:44Z

The hpsa firmware will bypass the cache for any request larger
than 1MB, so we should cap the request size to avoid any
performance degradation in 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 hpsa driver.

References: bsc#1025461

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

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 73daace478cb..b4c0bbea680c 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -952,7 +952,7 @@ static struct scsi_host_template hpsa_driver_template = {
#endif
.sdev_attrs = hpsa_sdev_attrs,
.shost_attrs = hpsa_shost_attrs,
- .max_sectors = 8192,
+ .max_sectors = 1024,
.no_write_same = 1,
};

--
2.12.3