Message-Id: <b07540e74fb24429fdccaefb938a3db13b662b04.1438245718.git.sowmini.varadhan@oracle.com>
Date:	Thu, 30 Jul 2015 04:55:46 -0400
From:	Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:	netdev@...r.kernel.org
Cc:	cwang@...pensource.com, ajaykumar.hotchandani@...cle.com,
	sowmini.varadhan@...cle.com
Subject: [PATCH RFC net-next 2/3] RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.

Register pernet subsys init/stop functions that will set up
and tear down per-net RDS-TCP listen endpoints. Unregister
pernet subusys functions on 'modprobe -r' to clean up these
end points.

Enable keepalive on both accept and connect socket endpoints.
The keepalive timer expiration will ensure that cleanup_net()
will eventually complete, allowing the pernet ->exit to be invoked.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@...cle.com>
---
 net/rds/tcp.c         |  112 ++++++++++++++++++++++++++++++++++++++++++------
 net/rds/tcp.h         |    7 ++-
 net/rds/tcp_connect.c |    6 ++-
 net/rds/tcp_listen.c  |   38 ++++-------------
 4 files changed, 115 insertions(+), 48 deletions(-)

diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index 98f5de3..fadf1a1 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -35,6 +35,8 @@
 #include <linux/in.h>
 #include <linux/module.h>
 #include <net/tcp.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
 
 #include "rds.h"
 #include "tcp.h"
@@ -250,16 +252,32 @@ static void rds_tcp_destroy_conns(void)
 	}
 }
 
-static void rds_tcp_exit(void)
+static void rds_tcp_destroy_conns_for_net(struct net *net)
 {
-	rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
-	rds_tcp_listen_stop();
-	rds_tcp_destroy_conns();
-	rds_trans_unregister(&rds_tcp_transport);
-	rds_tcp_recv_exit();
-	kmem_cache_destroy(rds_tcp_conn_slab);
+	struct rds_tcp_connection *tc, *_tc;
+	struct list_head tmp_list;
+
+	BUG_ON(!net);
+	INIT_LIST_HEAD(&tmp_list);
+	/* avoid calling conn_destroy with irqs off */
+	spin_lock_irq(&rds_tcp_conn_lock);
+	list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
+		struct net *c_net = read_pnet(&tc->conn->c_net);
+
+		if (net == c_net) {
+			list_del(&tc->t_tcp_node);
+			list_add_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) {
+		if (tc->conn->c_passive)
+			rds_conn_destroy(tc->conn->c_passive);
+		rds_conn_destroy(tc->conn);
+	}
 }
-module_exit(rds_tcp_exit);
+
+static void rds_tcp_exit(void);
 
 struct rds_transport rds_tcp_transport = {
 	.laddr_check		= rds_tcp_laddr_check,
@@ -281,6 +299,73 @@ struct rds_transport rds_tcp_transport = {
 	.t_prefer_loopback	= 1,
 };
 
+static int rds_tcp_netid;
+
+/* per-network namespace private data for this module */
+struct rds_tcp_net {
+	struct socket *rds_tcp_listen_sock;
+	struct work_struct rds_tcp_accept_w;
+};
+
+static void rds_tcp_accept_worker(struct work_struct *work)
+{
+	struct rds_tcp_net *rtn = container_of(work,
+					       struct rds_tcp_net,
+					       rds_tcp_accept_w);
+
+	while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
+		cond_resched();
+}
+
+void rds_tcp_accept_work(struct sock *sk)
+{
+	struct net *net = sock_net(sk);
+	struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
+
+	queue_work(rds_wq, &rtn->rds_tcp_accept_w);
+}
+
+static __net_init int rds_tcp_init_net(struct net *net)
+{
+	struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
+
+	rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net);
+	if (!rtn->rds_tcp_listen_sock) {
+		pr_warn("could not set up listen sock\n");
+		return -EAFNOSUPPORT;
+	}
+	INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
+	return 0;
+}
+
+static void __net_exit rds_tcp_exit_net(struct net *net)
+{
+	struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
+
+	rds_tcp_listen_stop(rtn->rds_tcp_listen_sock);
+	rtn->rds_tcp_listen_sock = NULL;
+	flush_work(&rtn->rds_tcp_accept_w);
+	rds_tcp_destroy_conns_for_net(net);
+}
+
+static struct pernet_operations rds_tcp_net_ops = {
+	.init = rds_tcp_init_net,
+	.exit = rds_tcp_exit_net,
+	.id = &rds_tcp_netid,
+	.size = sizeof(struct rds_tcp_net),
+};
+
+static void rds_tcp_exit(void)
+{
+	rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
+	unregister_pernet_subsys(&rds_tcp_net_ops);
+	rds_tcp_destroy_conns();
+	rds_trans_unregister(&rds_tcp_transport);
+	rds_tcp_recv_exit();
+	kmem_cache_destroy(rds_tcp_conn_slab);
+}
+module_exit(rds_tcp_exit);
+
 static int rds_tcp_init(void)
 {
 	int ret;
@@ -293,6 +378,10 @@ static int rds_tcp_init(void)
 		goto out;
 	}
 
+	ret = register_pernet_subsys(&rds_tcp_net_ops);
+	if (ret)
+		goto out_slab;
+
 	ret = rds_tcp_recv_init();
 	if (ret)
 		goto out_slab;
@@ -301,19 +390,14 @@ static int rds_tcp_init(void)
 	if (ret)
 		goto out_recv;
 
-	ret = rds_tcp_listen_init();
-	if (ret)
-		goto out_register;
-
 	rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 
 	goto out;
 
-out_register:
-	rds_trans_unregister(&rds_tcp_transport);
 out_recv:
 	rds_tcp_recv_exit();
 out_slab:
+	unregister_pernet_subsys(&rds_tcp_net_ops);
 	kmem_cache_destroy(rds_tcp_conn_slab);
 out:
 	return ret;
diff --git a/net/rds/tcp.h b/net/rds/tcp.h
index 0dbdd37..64f873c 100644
--- a/net/rds/tcp.h
+++ b/net/rds/tcp.h
@@ -52,6 +52,7 @@ u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc);
 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc);
 u64 rds_tcp_map_seq(struct rds_tcp_connection *tc, u32 seq);
 extern struct rds_transport rds_tcp_transport;
+void rds_tcp_accept_work(struct sock *sk);
 
 /* tcp_connect.c */
 int rds_tcp_conn_connect(struct rds_connection *conn);
@@ -59,9 +60,11 @@ void rds_tcp_conn_shutdown(struct rds_connection *conn);
 void rds_tcp_state_change(struct sock *sk);
 
 /* tcp_listen.c */
-int rds_tcp_listen_init(void);
-void rds_tcp_listen_stop(void);
+struct socket *rds_tcp_listen_init(struct net *);
+void rds_tcp_listen_stop(struct socket *);
 void rds_tcp_listen_data_ready(struct sock *sk);
+int rds_tcp_accept_one(struct socket *sock);
+int rds_tcp_keepalive(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 54a4609..a1d948e 100644
--- a/net/rds/tcp_connect.c
+++ b/net/rds/tcp_connect.c
@@ -112,10 +112,12 @@ int rds_tcp_conn_connect(struct rds_connection *conn)
 	rdsdebug("connect to address %pI4 returned %d\n", &conn->c_faddr, ret);
 	if (ret == -EINPROGRESS)
 		ret = 0;
-	if (ret == 0)
+	if (ret == 0) {
+		rds_tcp_keepalive(sock);
 		sock = NULL;
-	else
+	} else {
 		rds_tcp_restore_callbacks(sock, conn->c_transport_data);
+	}
 
 out:
 	if (sock)
diff --git a/net/rds/tcp_listen.c b/net/rds/tcp_listen.c
index 398ffe5..444d78d 100644
--- a/net/rds/tcp_listen.c
+++ b/net/rds/tcp_listen.c
@@ -38,14 +38,7 @@
 #include "rds.h"
 #include "tcp.h"
 
-/*
- * cheesy, but simple..
- */
-static void rds_tcp_accept_worker(struct work_struct *work);
-static DECLARE_WORK(rds_tcp_listen_work, rds_tcp_accept_worker);
-static struct socket *rds_tcp_listen_sock;
-
-static int rds_tcp_keepalive(struct socket *sock)
+int rds_tcp_keepalive(struct socket *sock)
 {
 	/* values below based on xs_udp_default_timeout */
 	int keepidle = 5; /* send a probe 'keepidle' secs after last data */
@@ -77,7 +70,7 @@ static int rds_tcp_keepalive(struct socket *sock)
 	return ret;
 }
 
-static int rds_tcp_accept_one(struct socket *sock)
+int rds_tcp_accept_one(struct socket *sock)
 {
 	struct socket *new_sock = NULL;
 	struct rds_connection *conn;
@@ -150,12 +143,6 @@ static int rds_tcp_accept_one(struct socket *sock)
 	return ret;
 }
 
-static void rds_tcp_accept_worker(struct work_struct *work)
-{
-	while (rds_tcp_accept_one(rds_tcp_listen_sock) == 0)
-		cond_resched();
-}
-
 void rds_tcp_listen_data_ready(struct sock *sk)
 {
 	void (*ready)(struct sock *sk);
@@ -176,26 +163,20 @@ void rds_tcp_listen_data_ready(struct sock *sk)
 	 * socket
 	 */
 	if (sk->sk_state == TCP_LISTEN)
-		queue_work(rds_wq, &rds_tcp_listen_work);
+		rds_tcp_accept_work(sk);
 
 out:
 	read_unlock(&sk->sk_callback_lock);
 	ready(sk);
 }
 
-int rds_tcp_listen_init(void)
+struct socket *rds_tcp_listen_init(struct net *net)
 {
 	struct sockaddr_in sin;
 	struct socket *sock = NULL;
 	int ret;
 
-	/* MUST call sock_create_kern directly so that we avoid get_net()
-	 * in sk_alloc(). Doing a get_net() will result in cleanup_net()
-	 * never getting invoked, which will leave sock and other things
-	 * in limbo.
-	 */
-	ret = sock_create_kern(current->nsproxy->net_ns, PF_INET,
-			       SOCK_STREAM, IPPROTO_TCP, &sock);
+	ret = sock_create_kern(net, PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
 	if (ret < 0)
 		goto out;
 
@@ -219,17 +200,15 @@ int rds_tcp_listen_init(void)
 	if (ret < 0)
 		goto out;
 
-	rds_tcp_listen_sock = sock;
-	sock = NULL;
+	return sock;
 out:
 	if (sock)
 		sock_release(sock);
-	return ret;
+	return NULL;
 }
 
-void rds_tcp_listen_stop(void)
+void rds_tcp_listen_stop(struct socket *sock)
 {
-	struct socket *sock = rds_tcp_listen_sock;
 	struct sock *sk;
 
 	if (!sock)
@@ -250,5 +229,4 @@ void rds_tcp_listen_stop(void)
 	/* wait for accepts to stop and close the socket */
 	flush_workqueue(rds_wq);
 	sock_release(sock);
-	rds_tcp_listen_sock = NULL;
 }
-- 
1.7.1

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