Fixed updating of ethertype in function skb_mpls_pop

The skb_mpls_pop was not updating ethertype of an ethernet packet if the
packet was originally received from a non ARPHRD_ETHER device.

In the below OVS data path flow, since the device corresponding to port 7
is an l3 device (ARPHRD_NONE) the skb_mpls_pop function does not update
the ethertype of the packet even though the previous push_eth action had
added an ethernet header to the packet.

recirc_id(0),in_port(7),eth_type(0x8847),
mpls(label=12/0xfffff,tc=0/0,ttl=0/0x0,bos=1/1),
actions:push_eth(src=00:00:00:00:00:00,dst=00:00:00:00:00:00),
pop_mpls(eth_type=0x800),4

Fixes: ed246cee09b9 ("net: core: move pop MPLS functionality from OvS to core helper")
Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 867e61d..312e80e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5529,12 +5529,14 @@ EXPORT_SYMBOL_GPL(skb_mpls_push);
  * @skb: buffer
  * @next_proto: ethertype of header after popped MPLS header
  * @mac_len: length of the MAC header
+ * @ethernet: flag to indicate if ethernet header is present in packet
  *
  * Expects skb->data at mac header.
  *
  * Returns 0 on success, -errno otherwise.
  */
-int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len)
+int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len,
+		 bool ethernet)
 {
 	int err;
 
@@ -5553,7 +5555,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len)
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, mac_len);
 
-	if (skb->dev && skb->dev->type == ARPHRD_ETHER) {
+	if (ethernet) {
 		struct ethhdr *hdr;
 
 		/* use mpls_hdr() to get ethertype to account for VLANs. */