sfc: extend common GRO interface to support CHECKSUM_COMPLETE

EF100 will use CHECKSUM_COMPLETE, but will also make use of
 efx_rx_packet_gro(), thus needs to be able to pass the checksum value
 into that function.
Drivers for older NICs pass in a csum of 0 to get the old semantics (use
 the RX flags for CHECKSUM_UNNECESSARY marking).
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/rx.c

@@ -411,7 +411,7 @@ void __efx_rx_packet(struct efx_channel *channel)
 		rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
 
 	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
-		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh);
+		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh, 0);
 	else
 		efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
 out:

drivers/net/ethernet/sfc/rx_common.c

@@ -510,7 +510,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic)
  */
 void
 efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
-		  unsigned int n_frags, u8 *eh)
+		  unsigned int n_frags, u8 *eh, __wsum csum)
 {
 	struct napi_struct *napi = &channel->napi_str;
 	struct efx_nic *efx = channel->efx;
@@ -528,8 +528,13 @@ efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
 	if (efx->net_dev->features & NETIF_F_RXHASH)
 		skb_set_hash(skb, efx_rx_buf_hash(efx, eh),
 			     PKT_HASH_TYPE_L3);
-	skb->ip_summed = ((rx_buf->flags & EFX_RX_PKT_CSUMMED) ?
-			  CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
+	if (csum) {
+		skb->csum = csum;
+		skb->ip_summed = CHECKSUM_COMPLETE;
+	} else {
+		skb->ip_summed = ((rx_buf->flags & EFX_RX_PKT_CSUMMED) ?
+				  CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
+	}
 	skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
 
 	for (;;) {

drivers/net/ethernet/sfc/rx_common.h

@@ -67,7 +67,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic);
 
 void
 efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
-		  unsigned int n_frags, u8 *eh);
+		  unsigned int n_frags, u8 *eh, __wsum csum);
 
 struct efx_rss_context *efx_alloc_rss_context_entry(struct efx_nic *efx);
 struct efx_rss_context *efx_find_rss_context_entry(struct efx_nic *efx, u32 id);