[PATCH 4.9 036/151] scsi: dc395x: fix DMA API usage in sg_update_list

[Greg Kroah-Hartman]

From: Christoph Hellwig <hch@xxxxxx>

[ Upstream commit 6c404a68bf83b4135a8a9aa1c388ebdf98e8ba7f ]

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

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/dc395x.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/dc395x.c b/drivers/scsi/dc395x.c
index 9da0ac360848f..830b2d2dcf206 100644
--- a/drivers/scsi/dc395x.c
+++ b/drivers/scsi/dc395x.c
@@ -1972,6 +1972,11 @@ 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;
-- 
2.20.1