commit a1a5344ddbe8fd3e080013b317ac9a664490cfdf
author Eric Dumazet <edumazet@google.com> Sun Oct 04 21:08:11 2015 -0700
committer David S. Miller <davem@davemloft.net> Mon Oct 05 02:45:27 2015 -0700
tree 75c793a05dd64db3df05f804e429bae45ead20d1
parent 004a5d0140ce1d05c1f5fce5df4baa2717a330e0

tcp: avoid two atomic ops for syncookies

inet_reqsk_alloc() is used to allocate a temporary request
in order to generate a SYNACK with a cookie. Then later,
syncookie validation also uses a temporary request.

These paths already took a reference on listener refcount,
we can avoid a couple of atomic operations.

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

net/ipv4/tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a95c8eb..ddadb31 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6042,9 +6042,11 @@
 }
 
 struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
-				      struct sock *sk_listener)
+				      struct sock *sk_listener,
+				      bool attach_listener)
 {
-	struct request_sock *req = reqsk_alloc(ops, sk_listener);
+	struct request_sock *req = reqsk_alloc(ops, sk_listener,
+					       attach_listener);
 
 	if (req) {
 		struct inet_request_sock *ireq = inet_rsk(req);
@@ -6143,7 +6145,7 @@
 		goto drop;
 	}
 
-	req = inet_reqsk_alloc(rsk_ops, sk);
+	req = inet_reqsk_alloc(rsk_ops, sk, !want_cookie);
 	if (!req)
 		goto drop;