net offloading: Convert checksums to use centrally computed features.

In order to compute the features for other offloads (primarily
scatter/gather), we need to first check the ability of the NIC to
offload the checksum for the packet.  Since we have already computed
this, we can directly use the result instead of figuring it out
again.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 2f838f1..3fe443b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1732,33 +1732,6 @@
 }
 EXPORT_SYMBOL(netif_device_attach);
 
-static bool can_checksum_protocol(unsigned long features, __be16 protocol)
-{
-	return ((features & NETIF_F_GEN_CSUM) ||
-		((features & NETIF_F_V4_CSUM) &&
-		 protocol == htons(ETH_P_IP)) ||
-		((features & NETIF_F_V6_CSUM) &&
-		 protocol == htons(ETH_P_IPV6)) ||
-		((features & NETIF_F_FCOE_CRC) &&
-		 protocol == htons(ETH_P_FCOE)));
-}
-
-static bool dev_can_checksum(struct net_device *dev, struct sk_buff *skb)
-{
-	__be16 protocol = skb->protocol;
-	int features = dev->features;
-
-	if (vlan_tx_tag_present(skb)) {
-		features &= dev->vlan_features;
-	} else if (protocol == htons(ETH_P_8021Q)) {
-		struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
-		protocol = veh->h_vlan_encapsulated_proto;
-		features &= dev->vlan_features;
-	}
-
-	return can_checksum_protocol(features, protocol);
-}
-
 /**
  * skb_dev_set -- assign a new device to a buffer
  * @skb: buffer for the new device
@@ -2015,6 +1988,17 @@
 	}
 }
 
+static bool can_checksum_protocol(unsigned long features, __be16 protocol)
+{
+	return ((features & NETIF_F_GEN_CSUM) ||
+		((features & NETIF_F_V4_CSUM) &&
+		 protocol == htons(ETH_P_IP)) ||
+		((features & NETIF_F_V6_CSUM) &&
+		 protocol == htons(ETH_P_IPV6)) ||
+		((features & NETIF_F_FCOE_CRC) &&
+		 protocol == htons(ETH_P_FCOE)));
+}
+
 static int harmonize_features(struct sk_buff *skb, __be16 protocol, int features)
 {
 	if (!can_checksum_protocol(protocol, features)) {
@@ -2117,7 +2101,7 @@
 			if (skb->ip_summed == CHECKSUM_PARTIAL) {
 				skb_set_transport_header(skb,
 					skb_checksum_start_offset(skb));
-				if (!dev_can_checksum(dev, skb) &&
+				if (!(features & NETIF_F_ALL_CSUM) &&
 				     skb_checksum_help(skb))
 					goto out_kfree_skb;
 			}