cxgb4: don't offload Rx checksums for IPv6 fragments

The checksum provided by the device doesn't include the L3 headers,
as IPv6 expects.
Signed-off-by: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cxgb4/sge.c

@@ -1593,14 +1593,15 @@ int t4_ethrx_handler(struct sge_rspq *q, const __be64 *rsp,
 
 	if (csum_ok && (pi->rx_offload & RX_CSO) &&
 	    (pkt->l2info & htonl(RXF_UDP | RXF_TCP))) {
-		if (!pkt->ip_frag)
+		if (!pkt->ip_frag) {
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
-		else {
+			rxq->stats.rx_cso++;
+		} else if (pkt->l2info & htonl(RXF_IP)) {
 			__sum16 c = (__force __sum16)pkt->csum;
 			skb->csum = csum_unfold(c);
 			skb->ip_summed = CHECKSUM_COMPLETE;
-		}
 			rxq->stats.rx_cso++;
+		}
 	} else
 		skb->ip_summed = CHECKSUM_NONE;
 

drivers/net/cxgb4/t4_msg.h

@@ -529,6 +529,8 @@ struct cpl_rx_pkt {
 	__be32 l2info;
 #define RXF_UDP (1 << 22)
 #define RXF_TCP (1 << 23)
+#define RXF_IP  (1 << 24)
+#define RXF_IP6 (1 << 25)
 	__be16 hdr_len;
 	__be16 err_vec;
 };