Merge tag 'powerpc-4.6-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...

[deliverable/linux.git] / net / rds / tcp_listen.c

diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 0936a4a32b476fdde5c7208fc465ec3324bbcf09..be263cdf268bae5b59a4746d4011d1042ede58cd 100644 (file)
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -76,7 +76,9 @@ int rds_tcp_accept_one(struct socket *sock)
        struct rds_connection *conn;
        int ret;
        struct inet_sock *inet;
-       struct rds_tcp_connection *rs_tcp;
+       struct rds_tcp_connection *rs_tcp = NULL;
+       int conn_state;
+       struct sock *nsk;
 
        ret = sock_create_kern(sock_net(sock->sk), sock->sk->sk_family,
                               sock->sk->sk_type, sock->sk->sk_protocol,
@@ -115,28 +117,44 @@ int rds_tcp_accept_one(struct socket *sock)
         * rds_tcp_state_change() will do that cleanup
         */
        rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
-       if (rs_tcp->t_sock &&
-           ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr)) {
-               struct sock *nsk = new_sock->sk;
-
-               nsk->sk_user_data = NULL;
-               nsk->sk_prot->disconnect(nsk, 0);
-               tcp_done(nsk);
-               new_sock = NULL;
-               ret = 0;
-               goto out;
-       } else if (rs_tcp->t_sock) {
-               rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
-               conn->c_outgoing = 0;
-       }
-
        rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING);
+       mutex_lock(&rs_tcp->t_conn_lock);
+       conn_state = rds_conn_state(conn);
+       if (conn_state != RDS_CONN_CONNECTING && conn_state != RDS_CONN_UP)
+               goto rst_nsk;
+       if (rs_tcp->t_sock) {
+               /* Need to resolve a duelling SYN between peers.
+                * We have an outstanding SYN to this peer, which may
+                * potentially have transitioned to the RDS_CONN_UP state,
+                * so we must quiesce any send threads before resetting
+                * c_transport_data.
+                */
+               wait_event(conn->c_waitq,
+                          !test_bit(RDS_IN_XMIT, &conn->c_flags));
+               if (ntohl(inet->inet_saddr) < ntohl(inet->inet_daddr)) {
+                       goto rst_nsk;
+               } else if (rs_tcp->t_sock) {
+                       rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
+                       conn->c_outgoing = 0;
+               }
+       }
        rds_tcp_set_callbacks(new_sock, conn);
-       rds_connect_complete(conn);
+       rds_connect_complete(conn); /* marks RDS_CONN_UP */
+       new_sock = NULL;
+       ret = 0;
+       goto out;
+rst_nsk:
+       /* reset the newly returned accept sock and bail */
+       nsk = new_sock->sk;
+       rds_tcp_stats_inc(s_tcp_listen_closed_stale);
+       nsk->sk_user_data = NULL;
+       nsk->sk_prot->disconnect(nsk, 0);
+       tcp_done(nsk);
        new_sock = NULL;
        ret = 0;
-
 out:
+       if (rs_tcp)
+               mutex_unlock(&rs_tcp->t_conn_lock);
        if (new_sock)
                sock_release(new_sock);
        return ret;