mpls: defer ttl decrement in mpls_forward()

Defer ttl decrement to optimize in tx_err case. There is no need
to decrease ttl in the case of goto tx_err.

Signed-off-by: Kangmin Park <l4stpr0gr4m@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 05a21dd..ffeb2df 100644 (file)
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -407,7 +407,6 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
        /* Verify ttl is valid */
        if (dec.ttl <= 1)
                goto err;
-       dec.ttl -= 1;
 
        /* Find the output device */
        out_dev = rcu_dereference(nh->nh_dev);
@@ -431,6 +430,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
        skb->dev = out_dev;
        skb->protocol = htons(ETH_P_MPLS_UC);
 
+       dec.ttl -= 1;
        if (unlikely(!new_header_size && dec.bos)) {
                /* Penultimate hop popping */
                if (!mpls_egress(dev_net(out_dev), rt, skb, dec))