net/packet: Remove redundant skb->protocol set

c72219b7 introduced tpacket_set_protocol that parses the Ethernet L2
header and sets skb->protocol if it's unset. It is no longer needed
since the introduction of packet_parse_headers. In case of SOCK_RAW and
unset skb->protocol, packet_parse_headers asks the driver to tell the
protocol number, and it's implemented for all Ethernet devices. As the
old function supported only Ethernet, no functionality is lost.
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -2413,15 +2413,6 @@ static void tpacket_destruct_skb(struct sk_buff *skb)
 	sock_wfree(skb);
 }
 
-static void tpacket_set_protocol(const struct net_device *dev,
-				 struct sk_buff *skb)
-{
-	if (dev->type == ARPHRD_ETHER) {
-		skb_reset_mac_header(skb);
-		skb->protocol = eth_hdr(skb)->h_proto;
-	}
-}
-
 static int __packet_snd_vnet_parse(struct virtio_net_hdr *vnet_hdr, size_t len)
 {
 	if ((vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
@@ -2492,8 +2483,6 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
 			return err;
 		if (!dev_validate_header(dev, skb->data, hdrlen))
 			return -EINVAL;
-		if (!skb->protocol)
-			tpacket_set_protocol(dev, skb);
 
 		data += hdrlen;
 		to_write -= hdrlen;