tunneling: Avoid extra copying if expanding headroom.

[openvswitch] / datapath / tunnel.c

diff --git a/datapath/tunnel.c b/datapath/tunnel.c
index 32632233659ee7cca37cb49194987fe2dd866c17..2bf61597d7a80eabe48d0cf452a004a60223d187 100644 (file)
--- a/datapath/tunnel.c
+++ b/datapath/tunnel.c
@@ -1027,27 +1027,6 @@ static struct rtable *find_route(struct vport *vport,
        }
 }
 
-static struct sk_buff *check_headroom(struct sk_buff *skb, int headroom)
-{
-       if (skb_headroom(skb) < headroom || skb_header_cloned(skb)) {
-               struct sk_buff *nskb = skb_realloc_headroom(skb, headroom + 16);
-               if (unlikely(!nskb)) {
-                       kfree_skb(skb);
-                       return ERR_PTR(-ENOMEM);
-               }
-
-               set_skb_csum_bits(skb, nskb);
-
-               if (skb->sk)
-                       skb_set_owner_w(nskb, skb->sk);
-
-               kfree_skb(skb);
-               return nskb;
-       }
-
-       return skb;
-}
-
 static inline bool need_linearize(const struct sk_buff *skb)
 {
        int i;
@@ -1084,10 +1063,14 @@ static struct sk_buff *handle_offloads(struct sk_buff *skb,
                        + mutable->tunnel_hlen
                        + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
 
-       skb = check_headroom(skb, min_headroom);
-       if (IS_ERR(skb)) {
-               err = PTR_ERR(skb);
-               goto error;
+       if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
+               int head_delta = SKB_DATA_ALIGN(min_headroom -
+                                               skb_headroom(skb) +
+                                               16);
+               err = pskb_expand_head(skb, max_t(int, head_delta, 0),
+                                       0, GFP_ATOMIC);
+               if (unlikely(err))
+                       goto error_free;
        }
 
        if (skb_is_gso(skb)) {