[PATCH net-next 3/4] net: stmmac: enhance VLAN protocol detection for GRO

[Konrad Leszczynski <konrad.leszczynski@intel.com>]

From: Piotr Warpechowski <piotr.warpechowski@intel.com>

Enhance protocol extraction in stmmac_has_ip_ethertype() by introducing
MAC offset parameter and changing:

__vlan_get_protocol() ->  __vlan_get_protocol_offset()

Add correct header length for VLAN tags, which enable Generic Receive
Offload (GRO) in VLAN.

Co-developed-by: Karol Jurczenia <karol.jurczenia@intel.com>
Signed-off-by: Karol Jurczenia <karol.jurczenia@intel.com>
Reviewed-by: Sebastian Basierski <sebastian.basierski@intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Piotr Warpechowski <piotr.warpechowski@intel.com>
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 8977e5aebc71..630ffb8dd0c3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4590,13 +4590,14 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
  */
 static bool stmmac_has_ip_ethertype(struct sk_buff *skb)
 {
-	int depth = 0;
+	int depth = 0, hlen;
 	__be16 proto;
 
-	proto = __vlan_get_protocol(skb, eth_header_parse_protocol(skb),
-				    &depth);
+	proto = __vlan_get_protocol_offset(skb, skb->protocol,
+					   skb_mac_offset(skb), &depth);
+	hlen = eth_type_vlan(skb->protocol) ? VLAN_ETH_HLEN : ETH_HLEN;
 
-	return (depth <= ETH_HLEN) &&
+	return (depth <= hlen) &&
 		(proto == htons(ETH_P_IP) || proto == htons(ETH_P_IPV6));
 }
 
-- 
2.34.1