RDS: TCP: Refactor connection destruction to handle multiple paths
A single rds_connection may have multiple rds_conn_paths that have
to be carefully and correctly destroyed, for both rmmod and
netns-delete cases.
For both cases, we extract a single rds_tcp_connection for
each conn into a temporary list, and then invoke rds_conn_destroy()
which iteratively dismantles every path in the rds_connection.
For the netns deletion case, we additionally have to make sure
that we do not leave a socket in TIME_WAIT state, as this will
hold up the netns deletion. Thus we call rds_tcp_conn_paths_destroy()
to reset state quickly.
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index c6b47f6..b327727 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -323,6 +323,17 @@
kmem_cache_free(rds_tcp_conn_slab, tc);
}
+static bool list_has_conn(struct list_head *list, struct rds_connection *conn)
+{
+ struct rds_tcp_connection *tc, *_tc;
+
+ list_for_each_entry_safe(tc, _tc, list, t_tcp_node) {
+ if (tc->t_cpath->cp_conn == conn)
+ return true;
+ }
+ return false;
+}
+
static void rds_tcp_destroy_conns(void)
{
struct rds_tcp_connection *tc, *_tc;
@@ -330,8 +341,10 @@
/* avoid calling conn_destroy with irqs off */
spin_lock_irq(&rds_tcp_conn_lock);
- list_splice(&rds_tcp_conn_list, &tmp_list);
- INIT_LIST_HEAD(&rds_tcp_conn_list);
+ list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
+ if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
+ list_move_tail(&tc->t_tcp_node, &tmp_list);
+ }
spin_unlock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
@@ -491,10 +504,30 @@
.size = sizeof(struct rds_tcp_net),
};
+/* explicitly send a RST on each socket, thereby releasing any socket refcnts
+ * that may otherwise hold up netns deletion.
+ */
+static void rds_tcp_conn_paths_destroy(struct rds_connection *conn)
+{
+ struct rds_conn_path *cp;
+ struct rds_tcp_connection *tc;
+ int i;
+ struct sock *sk;
+
+ for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+ cp = &conn->c_path[i];
+ tc = cp->cp_transport_data;
+ if (!tc->t_sock)
+ continue;
+ sk = tc->t_sock->sk;
+ sk->sk_prot->disconnect(sk, 0);
+ tcp_done(sk);
+ }
+}
+
static void rds_tcp_kill_sock(struct net *net)
{
struct rds_tcp_connection *tc, *_tc;
- struct sock *sk;
LIST_HEAD(tmp_list);
struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
@@ -507,13 +540,12 @@
if (net != c_net || !tc->t_sock)
continue;
- list_move_tail(&tc->t_tcp_node, &tmp_list);
+ if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
+ list_move_tail(&tc->t_tcp_node, &tmp_list);
}
spin_unlock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
- sk = tc->t_sock->sk;
- sk->sk_prot->disconnect(sk, 0);
- tcp_done(sk);
+ rds_tcp_conn_paths_destroy(tc->t_cpath->cp_conn);
rds_conn_destroy(tc->t_cpath->cp_conn);
}
}