[3.13.y-ckt stable] Patch "megaraid_sas: Do not use PAGE_SIZE for max_sectors" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    megaraid_sas: Do not use PAGE_SIZE for max_sectors

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt31.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 6d6c426268e88fbcd938643819c068e4e8506783 Mon Sep 17 00:00:00 2001
From: "sumit.saxena at avagotech.com" <sumit.saxena at avagotech.com>
Date: Thu, 15 Oct 2015 13:40:04 +0530
Subject: megaraid_sas: Do not use PAGE_SIZE for max_sectors

commit 357ae967ad66e357f78b5cfb5ab6ca07fb4a7758 upstream.

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.

Signed-off-by: Sumit Saxena <sumit.saxena at avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai at avagotech.com>
Reviewed-by: Tomas Henzl <thenzl at redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.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 e9e543c..d0caf0c 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -334,6 +334,8 @@ 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 9742005..c900e14 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3820,7 +3820,7 @@ 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;

--
1.9.1