net: Add utility function to copy skb hash

Adds skb_copy_hash to copy rxhash and l4_rxhash from one skb to another.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -764,6 +764,12 @@ static inline void skb_clear_hash_if_not_l4(struct sk_buff *skb)
 		skb_clear_hash(skb);
 }
 
+static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
+{
+	to->rxhash = from->rxhash;
+	to->l4_rxhash = from->l4_rxhash;
+};
+
 #ifdef NET_SKBUFF_DATA_USES_OFFSET
 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
 {

net/core/skbuff.c

@@ -712,9 +712,8 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	new->inner_network_header = old->inner_network_header;
 	new->inner_mac_header = old->inner_mac_header;
 	skb_dst_copy(new, old);
-	new->rxhash		= old->rxhash;
+	skb_copy_hash(new, old);
 	new->ooo_okay		= old->ooo_okay;
-	new->l4_rxhash		= old->l4_rxhash;
 	new->no_fcs		= old->no_fcs;
 	new->encapsulation	= old->encapsulation;
 #ifdef CONFIG_XFRM