tcp: do not lock listener to process SYN packets

[deliverable/linux.git] / net / ipv6 / tcp_ipv6.c

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index a215614cfb2b8c06352e131db28b4b547ccdcde8..33334f0c217dee6e6afa9eb1bf920dbb582835eb 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -438,7 +438,8 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
                              struct flowi *fl,
                              struct request_sock *req,
                              u16 queue_mapping,
-                             struct tcp_fastopen_cookie *foc)
+                             struct tcp_fastopen_cookie *foc,
+                             bool attach_req)
 {
        struct inet_request_sock *ireq = inet_rsk(req);
        struct ipv6_pinfo *np = inet6_sk(sk);
@@ -451,7 +452,7 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
                                               IPPROTO_TCP)) == NULL)
                goto done;
 
-       skb = tcp_make_synack(sk, dst, req, foc);
+       skb = tcp_make_synack(sk, dst, req, foc, attach_req);
 
        if (skb) {
                __tcp_v6_send_check(skb, &ireq->ir_v6_loc_addr,
@@ -1160,7 +1161,7 @@ out:
 }
 
 /* The socket must have it's spinlock held when we get
- * here.
+ * here, unless it is a TCP_LISTEN socket.
  *
  * We have a potential double-lock case here, so even when
  * doing backlog processing we use the BH locking scheme.
@@ -1414,9 +1415,15 @@ process:
        if (sk_filter(sk, skb))
                goto discard_and_relse;
 
-       sk_incoming_cpu_update(sk);
        skb->dev = NULL;
 
+       if (sk->sk_state == TCP_LISTEN) {
+               ret = tcp_v6_do_rcv(sk, skb);
+               goto put_and_return;
+       }
+
+       sk_incoming_cpu_update(sk);
+
        bh_lock_sock_nested(sk);
        tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
        ret = 0;
@@ -1431,6 +1438,7 @@ process:
        }
        bh_unlock_sock(sk);
 
+put_and_return:
        sock_put(sk);
        return ret ? -1 : 0;