1 files changed, 12 insertions, 4 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7d2dc015cd19..6451b83d81e9 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2944,7 +2944,7 @@ int tcp_send_synack(struct sock *sk)
 struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
                                 struct request_sock *req,
                                 struct tcp_fastopen_cookie *foc,
-                                bool attach_req)
+                                enum tcp_synack_type synack_type)
 {
         struct inet_request_sock *ireq = inet_rsk(req);
         const struct tcp_sock *tp = tcp_sk(sk);
@@ -2964,14 +2964,22 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
         /* Reserve space for headers. */
         skb_reserve(skb, MAX_TCP_HEADER);
 
-        if (attach_req) {
+        switch (synack_type) {
+        case TCP_SYNACK_NORMAL:
                 skb_set_owner_w(skb, req_to_sk(req));
-        } else {
+                break;
+        case TCP_SYNACK_COOKIE:
+                /* Under synflood, we do not attach skb to a socket,
+                 * to avoid false sharing.
+                 */
+                break;
+        case TCP_SYNACK_FASTOPEN:
                 /* sk is a const pointer, because we want to express multiple
                  * cpu might call us concurrently.
                  * sk->sk_wmem_alloc in an atomic, we can promote to rw.
                  */
                 skb_set_owner_w(skb, (struct sock *)sk);
+                break;
         }
         skb_dst_set(skb, dst);
 
@@ -3516,7 +3524,7 @@ int tcp_rtx_synack(const struct sock *sk, struct request_sock *req)
         int res;
 
         tcp_rsk(req)->txhash = net_tx_rndhash();
-        res = af_ops->send_synack(sk, NULL, &fl, req, NULL, true);
+        res = af_ops->send_synack(sk, NULL, &fl, req, NULL, TCP_SYNACK_NORMAL);
         if (!res) {
                 TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSYNRETRANS);