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authorEric Dumazet <edumazet@google.com>2016-05-13 09:16:40 -0700
committerDavid S. Miller <davem@davemloft.net>2016-05-16 13:46:23 -0400
commitea1627c20c3462168a087ccecc69084b55b9c0b2 (patch)
treee0b21e3af57979d1f5b1faf718582aaa4a6566b0 /net/ipv6
parent5022524308c64f2954ac206a8781b64a98cddf00 (diff)
tcp: minor optimizations around tcp_hdr() usage
tcp_hdr() is slightly more expensive than using skb->data in contexts where we know they point to the same byte. In receive path, tcp_v4_rcv() and tcp_v6_rcv() are in this situation, as tcp header has not been pulled yet. In output path, the same can be said when we just pushed the tcp header in the skb, in tcp_transmit_skb() and tcp_make_synack() Also factorize the two checks for tcb->tcp_flags & TCPHDR_SYN in tcp_transmit_skb() and pass tcp header pointer to tcp_ecn_send(), so that compiler can further optimize and avoid a reload. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/tcp_ipv6.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c4efaa97280c..79e33e02f11a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1369,9 +1369,9 @@ static int tcp_v6_rcv(struct sk_buff *skb)
if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
goto discard_it;
- th = tcp_hdr(skb);
+ th = (const struct tcphdr *)skb->data;
- if (th->doff < sizeof(struct tcphdr)/4)
+ if (unlikely(th->doff < sizeof(struct tcphdr)/4))
goto bad_packet;
if (!pskb_may_pull(skb, th->doff*4))
goto discard_it;
@@ -1379,7 +1379,7 @@ static int tcp_v6_rcv(struct sk_buff *skb)
if (skb_checksum_init(skb, IPPROTO_TCP, ip6_compute_pseudo))
goto csum_error;
- th = tcp_hdr(skb);
+ th = (const struct tcphdr *)skb->data;
hdr = ipv6_hdr(skb);
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