net: ethernet: mtk_eth_soc: unmap RX data before calling build_skb

Since build_skb accesses the data area (for initializing shinfo), dma unmap
needs to happen before that call

Signed-off-by: Felix Fietkau <nbd@nbd.name>
[Ilya: split build_skb cleanup fix into a separate commit]
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -1298,6 +1298,9 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 			goto release_desc;
 		}
 
+		dma_unmap_single(eth->dev, trxd.rxd1,
+				 ring->buf_size, DMA_FROM_DEVICE);
+
 		/* receive data */
 		skb = build_skb(data, ring->frag_size);
 		if (unlikely(!skb)) {
@@ -1307,8 +1310,6 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 		}
 		skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 
-		dma_unmap_single(eth->dev, trxd.rxd1,
-				 ring->buf_size, DMA_FROM_DEVICE);
 		pktlen = RX_DMA_GET_PLEN0(trxd.rxd2);
 		skb->dev = netdev;
 		skb_put(skb, pktlen);