dpaa2-eth: unmap the SGT buffer before accessing its contents

DMA unmap the Scatter/Gather table before going through the array to
unmap and free each of the header and data chunks. This is so we do not
touch the data between the dma_map and dma_unmap calls.

Fixes: 3dc709e0 ("dpaa2-eth: add support for software TSO")
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c

@@ -1136,6 +1136,10 @@ static void dpaa2_eth_free_tx_fd(struct dpaa2_eth_priv *priv,
 			sgt = (struct dpaa2_sg_entry *)(buffer_start +
 							priv->tx_data_offset);
 
+			/* Unmap the SGT buffer */
+			dma_unmap_single(dev, fd_addr, swa->tso.sgt_size,
+					 DMA_BIDIRECTIONAL);
+
 			/* Unmap and free the header */
 			tso_hdr = dpaa2_iova_to_virt(priv->iommu_domain, dpaa2_sg_get_addr(sgt));
 			dma_unmap_single(dev, dpaa2_sg_get_addr(sgt), TSO_HEADER_SIZE,
@@ -1147,10 +1151,6 @@ static void dpaa2_eth_free_tx_fd(struct dpaa2_eth_priv *priv,
 				dma_unmap_single(dev, dpaa2_sg_get_addr(&sgt[i]),
 						 dpaa2_sg_get_len(&sgt[i]), DMA_TO_DEVICE);
 
-			/* Unmap the SGT buffer */
-			dma_unmap_single(dev, fd_addr, swa->tso.sgt_size,
-					 DMA_BIDIRECTIONAL);
-
 			if (!swa->tso.is_last_fd)
 				should_free_skb = 0;
 		} else {