From c6f081c88ab76d5a40365b94c1f5839e099b2b2b Mon Sep 17 00:00:00 2001
From: "sumit.saxena@avagotech.com" <sumit.saxena@avagotech.com>
Date: Thu, 15 Oct 2015 13:40:04 +0530
Subject: [PATCH] megaraid_sas: Do not use PAGE_SIZE for max_sectors
Do not use PAGE_SIZE marco to calculate max_sectors per I/O
request. Driver code assumes PAGE_SIZE will be always 4096 which can
lead to wrongly calculated value if PAGE_SIZE is not 4096. This issue
was reported in Ubuntu Bugzilla Bug #1475166.
Cc: <stable@vger.kernel.org>
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
drivers/scsi/megaraid/megaraid_sas.h | 2 ++
drivers/scsi/megaraid/megaraid_sas_base.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 20c37541963f..ebf821b94cb6 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -364,6 +364,8 @@ enum MR_EVT_ARGS {
MR_EVT_ARGS_GENERIC,
};
+
+#define SGE_BUFFER_SIZE 4096
/*
* define constants for device list query options
*/
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index eaa81e552fd2..a9eb10ebc6ed 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4752,7 +4752,7 @@ static int megasas_init_fw(struct megasas_instance *instance)
instance->max_sectors_per_req = instance->max_num_sge *
- PAGE_SIZE / 512;
+ SGE_BUFFER_SIZE / 512;
if (tmp_sectors && (instance->max_sectors_per_req > tmp_sectors))
instance->max_sectors_per_req = tmp_sectors;
--
2.4.3