RDS: TCP: Synchronize accept() and connect() paths on t_conn_lock.

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

diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 0896187243d68c0ad1d3a324e7b396be367fa24e..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,
@@ -116,6 +118,10 @@ int rds_tcp_accept_one(struct socket *sock)
         */
        rs_tcp = (struct rds_tcp_connection *)conn->c_transport_data;
        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
@@ -126,14 +132,7 @@ int rds_tcp_accept_one(struct socket *sock)
                wait_event(conn->c_waitq,
                           !test_bit(RDS_IN_XMIT, &conn->c_flags));
                if (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;
+                       goto rst_nsk;
                } else if (rs_tcp->t_sock) {
                        rds_tcp_restore_callbacks(rs_tcp->t_sock, rs_tcp);
                        conn->c_outgoing = 0;
@@ -143,8 +142,19 @@ int rds_tcp_accept_one(struct socket *sock)
        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;