From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Date: Wed, 21 Jun 2017 13:40:13 -0700
Subject: rds: tcp: set linger to 1 when unloading a rds-tcp
Patch-mainline: v4.13-rc1
Git-commit: c14b0366813a8f6df7de181d8a333af7db6fb84e
References: bsc#1076830

If we are unloading the rds_tcp module, we can set linger to 1
and drop pending packets to accelerate reconnect. The peer will
end up resetting the connection based on new generation numbers
of the new incarnation, so hanging on to unsent TCP packets via
linger is mostly pointless in this case.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: Jenny Xu <jenny.x.xu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Kubecek <mkubecek@suse.cz>

---
 net/rds/connection.c  | 1 +
 net/rds/rds.h         | 3 ++-
 net/rds/tcp.h         | 1 +
 net/rds/tcp_connect.c | 2 ++
 net/rds/tcp_listen.c  | 2 +-
 5 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 6a5ebdea7d2e..501a0c1a6643 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -417,6 +417,7 @@ 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);
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 82d38ccf5e8b..e975113ccdec 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -137,7 +137,8 @@ struct rds_connection {
 	__be32			c_faddr;
 	unsigned int		c_loopback:1,
 				c_ping_triggered:1,
-				c_pad_to_32:30;
+				c_destroy_in_prog:1,
+				c_pad_to_32:29;
 	int			c_npaths;
 	struct rds_connection	*c_passive;
 	struct rds_transport	*c_trans;
diff --git a/net/rds/tcp.h b/net/rds/tcp.h
index 56ea6620fcf9..f8800b7ce79c 100644
--- a/net/rds/tcp.h
+++ b/net/rds/tcp.h
@@ -71,6 +71,7 @@ void rds_tcp_listen_data_ready(struct sock *sk);
 int rds_tcp_accept_one(struct socket *sock);
 int rds_tcp_keepalive(struct socket *sock);
 void *rds_tcp_listen_sock_def_readable(struct net *net);
+void rds_tcp_set_linger(struct socket *sock);
 
 /* tcp_recv.c */
 int rds_tcp_recv_init(void);
diff --git a/net/rds/tcp_connect.c b/net/rds/tcp_connect.c
index d6839d96d539..f9f2072b38dc 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -171,6 +171,8 @@ 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)
+			rds_tcp_set_linger(sock);
 		sock->ops->shutdown(sock, RCV_SHUTDOWN | SEND_SHUTDOWN);
 		lock_sock(sock->sk);
 		rds_tcp_restore_callbacks(sock, tc); /* tc->tc_sock = NULL */
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index ff72a122ce12..fd4a92332aea 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -112,7 +112,7 @@ struct rds_tcp_connection *rds_tcp_accept_one_path(struct rds_connection *conn)
 	return NULL;
 }
 
-static void rds_tcp_set_linger(struct socket *sock)
+void rds_tcp_set_linger(struct socket *sock)
 {
 	struct linger no_linger = {
 		.l_onoff = 1,
-- 
2.16.1