net: fec: using the standard return codes when xdp xmit errors

This patch standardizes the inconsistent return values for unsuccessful
XDP transmits by using standardized error codes (-EBUSY or -ENOMEM).

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -3799,7 +3799,7 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep,
 	if (entries_free < MAX_SKB_FRAGS + 1) {
 		netdev_err(fep->netdev, "NOT enough BD for SG!\n");
 		xdp_return_frame(frame);
-		return NETDEV_TX_BUSY;
+		return -EBUSY;
 	}
 
 	/* Fill in a Tx ring entry */
@@ -3813,7 +3813,7 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep,
 	dma_addr = dma_map_single(&fep->pdev->dev, frame->data,
 				  frame->len, DMA_TO_DEVICE);
 	if (dma_mapping_error(&fep->pdev->dev, dma_addr))
-		return FEC_ENET_XDP_CONSUMED;
+		return -ENOMEM;
 
 	status |= (BD_ENET_TX_INTR | BD_ENET_TX_LAST);
 	if (fep->bufdesc_ex)
@@ -3869,7 +3869,7 @@ static int fec_enet_xdp_xmit(struct net_device *dev,
 	__netif_tx_lock(nq, cpu);
 
 	for (i = 0; i < num_frames; i++) {
-		if (fec_enet_txq_xmit_frame(fep, txq, frames[i]) != 0)
+		if (fec_enet_txq_xmit_frame(fep, txq, frames[i]) < 0)
 			break;
 		sent_frames++;
 	}