From: Tomas Henzl <thenzl@redhat.com>
Date: Thu, 24 May 2018 17:12:46 +0200
Subject: [PATCH] scsi: mpt3sas: Add an I/O barrier
References: bsc#1086906,FATE#324923
Git-commit: 10ee1f2206a3f5aa869bede4b7505b24203a7715
Patch-mainline: v4.18-rc1

A barrier should be added to ensure proper ordering of memory mapped
writes.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Chaitra P B <chaitra.basappa@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index c79b56b1c2f4..cde39a8742d4 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -3348,6 +3348,7 @@ _base_mpi_ep_writeq(__u64 b, volatile void __iomem *addr,
 	spin_lock_irqsave(writeq_lock, flags);
 	writel((u32)(data_out), addr);
 	writel((u32)(data_out >> 32), (addr + 4));
+	mmiowb();
 	spin_unlock_irqrestore(writeq_lock, flags);
 }
 
-- 
2.12.3