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Commit afb4164d authored by Sowmini Varadhan's avatar Sowmini Varadhan Committed by David S. Miller
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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: default avatarSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02105b2c

net/rds/tcp.c

+39 −7
Original line number Diff line number Diff line
@@ -323,6 +323,17 @@ static void rds_tcp_conn_free(void *arg) 
	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 @@ static void rds_tcp_destroy_conns(void) 


	/* 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 @@ static struct pernet_operations rds_tcp_net_ops = { 
	.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 @@ static void rds_tcp_kill_sock(struct net *net) 


		if (net != c_net || !tc->t_sock)

			continue;

		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);

	}

}