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>

1 files changed, 5 insertions, 3 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a95c8eb04ff7..ddadb318e850 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6042,9 +6042,11 @@ static void tcp_openreq_init(struct request_sock *req,
 }
 
 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 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
                 goto drop;
         }
 
-        req = inet_reqsk_alloc(rsk_ops, sk);
+        req = inet_reqsk_alloc(rsk_ops, sk, !want_cookie);
         if (!req)
                 goto drop;