net: relax expensive skb_unclone() in iptunnel_handle_offloads()
Locally generated TCP GSO packets having to go through a GRE/SIT/IPIP
tunnel have to go through an expensive skb_unclone()
Reallocating skb->head is a lot of work.
Test should really check if a 'real clone' of the packet was done.
TCP does not care if the original gso_type is changed while the packet
travels in the stack.
This adds skb_header_unclone() which is a variant of skb_clone()
using skb_header_cloned() check instead of skb_cloned().
This variant can probably be used from other points.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index c84a5a1..c413c58 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1325,6 +1325,16 @@
return dataref != 1;
}
+static inline int skb_header_unclone(struct sk_buff *skb, gfp_t pri)
+{
+ might_sleep_if(gfpflags_allow_blocking(pri));
+
+ if (skb_header_cloned(skb))
+ return pskb_expand_head(skb, 0, 0, pri);
+
+ return 0;
+}
+
/**
* skb_header_release - release reference to header
* @skb: buffer to operate on
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 786fa7c..9118b0e 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -157,7 +157,7 @@
}
if (skb_is_gso(skb)) {
- err = skb_unclone(skb, GFP_ATOMIC);
+ err = skb_header_unclone(skb, GFP_ATOMIC);
if (unlikely(err))
return err;
skb_shinfo(skb)->gso_type |= gso_type_mask;