scsi: mpt3sas: Add an I/O barrier

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>

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 61f93a1..293f041 100644 (file)
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -3344,6 +3344,7 @@ _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);
 }