rds: Use atomic flag to track connections being destroyed

Replace c_destroy_in_prog by using a bit in cp_flags that
can set/tested atomically.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/connection.c

@@ -366,7 +366,7 @@ void rds_conn_shutdown(struct rds_conn_path *cp)
 	 * to the conn hash, so we never trigger a reconnect on this
 	 * conn - the reconnect is always triggered by the active peer. */
 	cancel_delayed_work_sync(&cp->cp_conn_w);
-	if (conn->c_destroy_in_prog)
+	if (test_bit(RDS_DESTROY_PENDING, &cp->cp_flags))
 		return;
 	rcu_read_lock();
 	if (!hlist_unhashed(&conn->c_hash_node)) {
@@ -384,6 +384,8 @@ static void rds_conn_path_destroy(struct rds_conn_path *cp)
 {
 	struct rds_message *rm, *rtmp;
 
+	set_bit(RDS_DESTROY_PENDING, &cp->cp_flags);
+
 	if (!cp->cp_transport_data)
 		return;
 
@@ -426,7 +428,6 @@ void rds_conn_destroy(struct rds_connection *conn)
 		 "%pI4\n", conn, &conn->c_laddr,
 		 &conn->c_faddr);
 
-	conn->c_destroy_in_prog = 1;
 	/* Ensure conn will not be scheduled for reconnect */
 	spin_lock_irq(&rds_conn_lock);
 	hlist_del_init_rcu(&conn->c_hash_node);
@@ -685,7 +686,7 @@ void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
 {
 	atomic_set(&cp->cp_state, RDS_CONN_ERROR);
 
-	if (!destroy && cp->cp_conn->c_destroy_in_prog)
+	if (!destroy && test_bit(RDS_DESTROY_PENDING, &cp->cp_flags))
 		return;
 
 	queue_work(rds_wq, &cp->cp_down_w);

net/rds/rds.h

@@ -88,6 +88,7 @@ enum {
 #define RDS_RECONNECT_PENDING	1
 #define RDS_IN_XMIT		2
 #define RDS_RECV_REFILL		3
+#define	RDS_DESTROY_PENDING	4
 
 /* Max number of multipaths per RDS connection. Must be a power of 2 */
 #define	RDS_MPATH_WORKERS	8
@@ -139,8 +140,7 @@ struct rds_connection {
 	__be32			c_faddr;
 	unsigned int		c_loopback:1,
 				c_ping_triggered:1,
-				c_destroy_in_prog:1,
-				c_pad_to_32:29;
+				c_pad_to_32:30;
 	int			c_npaths;
 	struct rds_connection	*c_passive;
 	struct rds_transport	*c_trans;

net/rds/tcp_connect.c

@@ -170,7 +170,7 @@ void rds_tcp_conn_path_shutdown(struct rds_conn_path *cp)
 		 cp->cp_conn, tc, sock);
 
 	if (sock) {
-		if (cp->cp_conn->c_destroy_in_prog)
+		if (test_bit(RDS_DESTROY_PENDING, &cp->cp_flags))
 			rds_tcp_set_linger(sock);
 		sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		lock_sock(sock->sk);