commit cfbba49d80be6cf8d3872b66fc5421f119843b36
author Patrick McHardy <kaber@trash.net> Mon Jul 09 15:33:40 2007 -0700
committer David S. Miller <davem@sunset.davemloft.net> Tue Jul 10 22:19:05 2007 -0700
tree 2e2a966d43b6cd80c2ae7c8d5e37ab4c8a0262ad
parent 4839c52b01ca91be1c62761e08fb3deb3881e857

[NET]: Avoid copying writable clones in tunnel drivers

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 6328293..5c14ed6 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -809,7 +809,8 @@
 
 	max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen;
 
-	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
+	if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
+	    (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 		if (!new_skb) {
 			ip_rt_put(rt);