scsi: dc395x: fix dma API usage in srb_done

BugLink: https://bugs.launchpad.net/bugs/1854855

[ Upstream commit 3a5bd702 ]

We can't just transfer ownership to the CPU and then unmap, as this will
break with swiotlb.

Instead unmap the command and sense buffer a little earlier in the I/O
completion handler and get rid of the pci_dma_sync_sg_for_cpu call
entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/scsi/dc395x.c

@@ -3450,14 +3450,12 @@ static void srb_done(struct AdapterCtlBlk *acb, struct DeviceCtlBlk *dcb,
 		}
 	}
 
-	if (dir != PCI_DMA_NONE && scsi_sg_count(cmd))
-		pci_dma_sync_sg_for_cpu(acb->dev, scsi_sglist(cmd),
-					scsi_sg_count(cmd), dir);
-
 	ckc_only = 0;
 /* Check Error Conditions */
       ckc_e:
 
+	pci_unmap_srb(acb, srb);
+
 	if (cmd->cmnd[0] == INQUIRY) {
 		unsigned char *base = NULL;
 		struct ScsiInqData *ptr;
@@ -3511,7 +3509,6 @@ static void srb_done(struct AdapterCtlBlk *acb, struct DeviceCtlBlk *dcb,
 			cmd, cmd->result);
 		srb_free_insert(acb, srb);
 	}
-	pci_unmap_srb(acb, srb);
 
 	cmd->scsi_done(cmd);
 	waiting_process_next(acb);