net: ipv4: avoid repeated calls to ip_skb_dst_mtu helper
ip_skb_dst_mtu is small inline helper, but its called in several places.
before: 17061 44 0 17105 42d1 net/ipv4/ip_output.o
after: 16805 44 0 16849 41d1 net/ipv4/ip_output.o
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 451b009..d6dd8ba 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -84,6 +84,7 @@
EXPORT_SYMBOL(sysctl_ip_default_ttl);
static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+ unsigned int mtu,
int (*output)(struct sock *, struct sk_buff *));
/* Generate a checksum for an outgoing IP datagram. */
@@ -219,7 +220,8 @@
return -EINVAL;
}
-static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb)
+static int ip_finish_output_gso(struct sock *sk, struct sk_buff *skb,
+ unsigned int mtu)
{
netdev_features_t features;
struct sk_buff *segs;
@@ -227,7 +229,7 @@
/* common case: locally created skb or seglen is <= mtu */
if (((IPCB(skb)->flags & IPSKB_FORWARDED) == 0) ||
- skb_gso_network_seglen(skb) <= ip_skb_dst_mtu(skb))
+ skb_gso_network_seglen(skb) <= mtu)
return ip_finish_output2(sk, skb);
/* Slowpath - GSO segment length is exceeding the dst MTU.
@@ -251,7 +253,7 @@
int err;
segs->next = NULL;
- err = ip_fragment(sk, segs, ip_finish_output2);
+ err = ip_fragment(sk, segs, mtu, ip_finish_output2);
if (err && ret == 0)
ret = err;
@@ -263,6 +265,8 @@
static int ip_finish_output(struct sock *sk, struct sk_buff *skb)
{
+ unsigned int mtu;
+
#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
/* Policy lookup after SNAT yielded a new policy */
if (skb_dst(skb)->xfrm) {
@@ -270,11 +274,12 @@
return dst_output_sk(sk, skb);
}
#endif
+ mtu = ip_skb_dst_mtu(skb);
if (skb_is_gso(skb))
- return ip_finish_output_gso(sk, skb);
+ return ip_finish_output_gso(sk, skb, mtu);
- if (skb->len > ip_skb_dst_mtu(skb))
- return ip_fragment(sk, skb, ip_finish_output2);
+ if (skb->len > mtu)
+ return ip_fragment(sk, skb, mtu, ip_finish_output2);
return ip_finish_output2(sk, skb);
}
@@ -482,10 +487,10 @@
}
static int ip_fragment(struct sock *sk, struct sk_buff *skb,
+ unsigned int mtu,
int (*output)(struct sock *, struct sk_buff *))
{
struct iphdr *iph = ip_hdr(skb);
- unsigned int mtu = ip_skb_dst_mtu(skb);
if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
(IPCB(skb)->frag_max_size &&