nfp: add buffer drop/recycle helper for RX

nfp_net_rx() is quite long already and about to get longer.
Move buffer drop/recycle to a helper.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1330,6 +1330,20 @@ nfp_net_parse_meta(struct net_device *netdev, struct sk_buff *skb,
 	return data;
 }
 
+static void
+nfp_net_rx_drop(struct nfp_net_r_vector *r_vec, struct nfp_net_rx_ring *rx_ring,
+		struct nfp_net_rx_buf *rxbuf, struct sk_buff *skb)
+{
+	u64_stats_update_begin(&r_vec->rx_sync);
+	r_vec->rx_drops++;
+	u64_stats_update_end(&r_vec->rx_sync);
+
+	if (rxbuf)
+		nfp_net_rx_give_one(rx_ring, rxbuf->skb, rxbuf->dma_addr);
+	if (skb)
+		dev_kfree_skb_any(skb);
+}
+
 /**
  * nfp_net_rx() - receive up to @budget packets on @rx_ring
  * @rx_ring:   RX ring to receive from
@@ -1372,11 +1386,8 @@ static int nfp_net_rx(struct nfp_net_rx_ring *rx_ring, int budget)
 		new_skb = nfp_net_rx_alloc_one(rx_ring, &new_dma_addr,
 					       nn->fl_bufsz);
 		if (!new_skb) {
-			nfp_net_rx_give_one(rx_ring, rx_ring->rxbufs[idx].skb,
-					    rx_ring->rxbufs[idx].dma_addr);
-			u64_stats_update_begin(&r_vec->rx_sync);
-			r_vec->rx_drops++;
-			u64_stats_update_end(&r_vec->rx_sync);
+			nfp_net_rx_drop(r_vec, rx_ring, &rx_ring->rxbufs[idx],
+					NULL);
 			continue;
 		}
 
@@ -1420,12 +1431,8 @@ static int nfp_net_rx(struct nfp_net_rx_ring *rx_ring, int budget)
 
 			end = nfp_net_parse_meta(nn->netdev, skb, meta_len);
 			if (unlikely(end != skb->data)) {
-				u64_stats_update_begin(&r_vec->rx_sync);
-				r_vec->rx_drops++;
-				u64_stats_update_end(&r_vec->rx_sync);
-
-				dev_kfree_skb_any(skb);
 				nn_warn_ratelimit(nn, "invalid RX packet metadata\n");
+				nfp_net_rx_drop(r_vec, rx_ring, NULL, skb);
 				continue;
 			}
 		}