From 6015c71e656bb6895b416c31a8b7db457e45cecf Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Nov 2018 15:03:21 -0800 Subject: tcp: md5: add tcp_md5_needed jump label Most linux hosts never setup TCP MD5 keys. We can avoid a cache line miss (accessing tp->md5ig_info) on RX and TX using a jump label. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_output.c') diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index e4c1e51b18c1..d3b691f3a9e8 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -594,7 +594,8 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (unlikely(rcu_access_pointer(tp->md5sig_info))) { + if (static_key_false(&tcp_md5_needed) && + rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { opts->options |= OPTION_MD5; @@ -730,7 +731,8 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (unlikely(rcu_access_pointer(tp->md5sig_info))) { + if (static_key_false(&tcp_md5_needed) && + rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { opts->options |= OPTION_MD5; -- cgit v1.2.3