netfilter: bridge: refactor conditional in br_nf_dev_queue_xmit

simpilifies followup patch that re-works brnf ip_fragment handling.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/bridge/br_netfilter.c

@@ -803,13 +803,16 @@ static int br_nf_dev_queue_xmit(struct sk_buff *skb)
 {
 	int ret;
 	int frag_max_size;
+	unsigned int mtu_reserved;
 
+	if (skb_is_gso(skb) || skb->protocol != htons(ETH_P_IP))
+		return br_dev_queue_push_xmit(skb);
+
+	mtu_reserved = nf_bridge_mtu_reduction(skb);
 	/* This is wrong! We should preserve the original fragment
 	 * boundaries by preserving frag_list rather than refragmenting.
 	 */
-	if (skb->protocol == htons(ETH_P_IP) &&
-	    skb->len + nf_bridge_mtu_reduction(skb) > skb->dev->mtu &&
-	    !skb_is_gso(skb)) {
+	if (skb->len + mtu_reserved > skb->dev->mtu) {
 		frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
 		if (br_parse_ip_options(skb))
 			/* Drop invalid packet */