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 <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4904250a9aac..efc6fef692ff 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -970,10 +970,13 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
  * We need to maintain these in the sk structure.
  */
 
+struct static_key tcp_md5_needed __read_mostly;
+EXPORT_SYMBOL(tcp_md5_needed);
+
 /* Find the Key structure for an address.  */
-struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
-                                         const union tcp_md5_addr *addr,
-                                         int family)
+struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk,
+                                           const union tcp_md5_addr *addr,
+                                           int family)
 {
         const struct tcp_sock *tp = tcp_sk(sk);
         struct tcp_md5sig_key *key;
@@ -1011,7 +1014,7 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
         }
         return best_match;
 }
-EXPORT_SYMBOL(tcp_md5_do_lookup);
+EXPORT_SYMBOL(__tcp_md5_do_lookup);
 
 static struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
                                                       const union tcp_md5_addr *addr,