1 files changed, 42 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 176645762e49..1ff0b0e93804 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -615,6 +615,45 @@ static inline bool is_last_ethertype_ip(struct sk_buff *skb, int *network_depth)
 	return (ethertype == htons(ETH_P_IP) || ethertype == htons(ETH_P_IPV6));
 }
 
+static __be32 mlx5e_get_fcs(struct sk_buff *skb)
+{
+	int last_frag_sz, bytes_in_prev, nr_frags;
+	u8 *fcs_p1, *fcs_p2;
+	skb_frag_t *last_frag;
+	__be32 fcs_bytes;
+
+	if (!skb_is_nonlinear(skb))
+		return *(__be32 *)(skb->data + skb->len - ETH_FCS_LEN);
+
+	nr_frags = skb_shinfo(skb)->nr_frags;
+	last_frag = &skb_shinfo(skb)->frags[nr_frags - 1];
+	last_frag_sz = skb_frag_size(last_frag);
+
+	/* If all FCS data is in last frag */
+	if (last_frag_sz >= ETH_FCS_LEN)
+		return *(__be32 *)(skb_frag_address(last_frag) +
+				   last_frag_sz - ETH_FCS_LEN);
+
+	fcs_p2 = (u8 *)skb_frag_address(last_frag);
+	bytes_in_prev = ETH_FCS_LEN - last_frag_sz;
+
+	/* Find where the other part of the FCS is - Linear or another frag */
+	if (nr_frags == 1) {
+		fcs_p1 = skb_tail_pointer(skb);
+	} else {
+		skb_frag_t *prev_frag = &skb_shinfo(skb)->frags[nr_frags - 2];
+
+		fcs_p1 = skb_frag_address(prev_frag) +
+			    skb_frag_size(prev_frag);
+	}
+	fcs_p1 -= bytes_in_prev;
+
+	memcpy(&fcs_bytes, fcs_p1, bytes_in_prev);
+	memcpy(((u8 *)&fcs_bytes) + bytes_in_prev, fcs_p2, last_frag_sz);
+
+	return fcs_bytes;
+}
+
 static inline void mlx5e_handle_csum(struct net_device *netdev,
 				     struct mlx5_cqe64 *cqe,
 				     struct mlx5e_rq *rq,
@@ -643,6 +682,9 @@ static inline void mlx5e_handle_csum(struct net_device *netdev,
 			skb->csum = csum_partial(skb->data + ETH_HLEN,
 						 network_depth - ETH_HLEN,
 						 skb->csum);
+		if (unlikely(netdev->features & NETIF_F_RXFCS))
+			skb->csum = csum_add(skb->csum,
+					     (__force __wsum)mlx5e_get_fcs(skb));
 		rq->stats.csum_complete++;
 		return;
 	}