From: Christoph Hellwig <hch@lst.de>
Date: Thu, 11 Oct 2018 16:17:15 +0200
Subject: scsi: dc395x: fix DMA API usage in sg_update_list
Git-commit: 6c404a68bf83b4135a8a9aa1c388ebdf98e8ba7f
Patch-mainline: v4.20-rc1
References: git-fixes

We need to transfer device ownership to the CPU before we can manipulate
the mapped data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/dc395x.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index 8d7a26a33951..f3b65e5efe2b 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -1871,6 +1871,11 @@ static void sg_update_list(struct ScsiReqBlk *srb, u32 left)
 			xferred -= psge->length;
 		} else {
 			/* Partial SG entry done */
+			pci_dma_sync_single_for_cpu(srb->dcb->
+					    acb->dev,
+					    srb->sg_bus_addr,
+					    SEGMENTX_LEN,
+					    PCI_DMA_TODEVICE);
 			psge->length -= xferred;
 			psge->address += xferred;
 			srb->sg_index = idx;