dpaa2-eth: check the result of skb_to_sgvec()

Before passing the result of skb_to_sgvec() to dma_map_sg() check if any
error was returned.
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

@@ -611,6 +611,10 @@ static int build_sg_fd(struct dpaa2_eth_priv *priv,
 
 	sg_init_table(scl, nr_frags + 1);
 	num_sg = skb_to_sgvec(skb, scl, 0, skb->len);
+	if (unlikely(num_sg < 0)) {
+		err = -ENOMEM;
+		goto dma_map_sg_failed;
+	}
 	num_dma_bufs = dma_map_sg(dev, scl, num_sg, DMA_BIDIRECTIONAL);
 	if (unlikely(!num_dma_bufs)) {
 		err = -ENOMEM;