[NET]: Merge TSO/UFO fields in sk_buff

Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not
going to scale if we add any more segmentation methods (e.g., DCCP).  So
let's merge them.

They were used to tell the protocol of a packet.  This function has been
subsumed by the new gso_type field.  This is essentially a set of netdev
feature bits (shifted by 16 bits) that are required to process a specific
skb.  As such it's easy to tell whether a given device can process a GSO
skb: you just have to and the gso_type field and the netdev's features
field.

I've made gso_type a conjunction.  The idea is that you have a base type
(e.g., SKB_GSO_TCPV4) that can be modified further to support new features.
For example, if we add a hardware TSO type that supports ECN, they would
declare NETIF_F_TSO | NETIF_F_TSO_ECN.  All TSO packets with CWR set would
have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO
packets would be SKB_GSO_TCPV4.  This means that only the CWR packets need
to be emulated in software.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index a373ccb..32b7d44 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -2394,7 +2394,7 @@
 	uint8_t ipcss, ipcso, tucss, tucso, hdr_len;
 	int err;
 
-	if (skb_shinfo(skb)->tso_size) {
+	if (skb_shinfo(skb)->gso_size) {
 		if (skb_header_cloned(skb)) {
 			err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
 			if (err)
@@ -2402,7 +2402,7 @@
 		}
 
 		hdr_len = ((skb->h.raw - skb->data) + (skb->h.th->doff << 2));
-		mss = skb_shinfo(skb)->tso_size;
+		mss = skb_shinfo(skb)->gso_size;
 		if (skb->protocol == htons(ETH_P_IP)) {
 			skb->nh.iph->tot_len = 0;
 			skb->nh.iph->check = 0;
@@ -2519,7 +2519,7 @@
 		 * tso gets written back prematurely before the data is fully
 		 * DMA'd to the controller */
 		if (!skb->data_len && tx_ring->last_tx_tso &&
-		    !skb_shinfo(skb)->tso_size) {
+		    !skb_shinfo(skb)->gso_size) {
 			tx_ring->last_tx_tso = 0;
 			size -= 4;
 		}
@@ -2757,7 +2757,7 @@
 	}
 
 #ifdef NETIF_F_TSO
-	mss = skb_shinfo(skb)->tso_size;
+	mss = skb_shinfo(skb)->gso_size;
 	/* The controller does a simple calculation to
 	 * make sure there is enough room in the FIFO before
 	 * initiating the DMA for each buffer.  The calc is:
@@ -2807,7 +2807,7 @@
 #ifdef NETIF_F_TSO
 	/* Controller Erratum workaround */
 	if (!skb->data_len && tx_ring->last_tx_tso &&
-	    !skb_shinfo(skb)->tso_size)
+	    !skb_shinfo(skb)->gso_size)
 		count++;
 #endif