Commit 69b92b5b authored by Sowmini Varadhan's avatar Sowmini Varadhan Committed by David S. Miller
Browse files

rds: tcp: send handshake ping-probe from passive endpoint 



The RDS handshake ping probe added by commit 5916e2c1
("RDS: TCP: Enable multipath RDS for TCP") is sent from rds_sendmsg()
before the first data packet is sent to a peer. If the conversation
is not bidirectional  (i.e., one side is always passive and never
invokes rds_sendmsg()) and the passive side restarts its rds_tcp
module, a new HS ping probe needs to be sent, so that the number
of paths can be re-established.

This patch achieves that by sending a HS ping probe from
rds_tcp_accept_one() when c_npaths is 0 (i.e., we have not done
a handshake probe with this peer yet).

Signed-off-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: default avatarJenny Xu <jenny.x.xu@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6d659237

net/rds/rds.h

+1 −0
Original line number Diff line number Diff line
@@ -827,6 +827,7 @@ void rds_send_drop_acked(struct rds_connection *conn, u64 ack, 
			 is_acked_func is_acked);

void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,

			      is_acked_func is_acked);

void rds_send_ping(struct rds_connection *conn, int cp_index);

int rds_send_pong(struct rds_conn_path *cp, __be16 dport);



/* rdma.c */

net/rds/recv.c

+3 −3
Original line number Diff line number Diff line
@@ -227,6 +227,7 @@ static void rds_recv_hs_exthdrs(struct rds_header *hdr, 
	}

	/* if RDS_EXTHDR_NPATHS was not found, default to a single-path */

	conn->c_npaths = max_t(int, conn->c_npaths, 1);

	conn->c_ping_triggered = 0;

	rds_conn_peer_gen_update(conn, new_peer_gen_num);

}
@@ -244,8 +245,7 @@ static void rds_recv_hs_exthdrs(struct rds_header *hdr, 
 *    called after reception of the probe-pong on all mprds_paths.

 *    Otherwise (sender of probe-ping is not the smaller ip addr): just call

 *    rds_conn_path_connect_if_down on the hashed path. (see rule 4)

 * 4. when cp_index > 0, rds_connect_worker must only trigger

 *    a connection if laddr < faddr.

 * 4. rds_connect_worker must only trigger a connection if laddr < faddr.

 * 5. sender may end up queuing the packet on the cp. will get sent out later.

 *    when connection is completed.

 */
@@ -256,7 +256,7 @@ static void rds_start_mprds(struct rds_connection *conn) 


	if (conn->c_npaths > 1 &&

	    IS_CANONICAL(conn->c_laddr, conn->c_faddr)) {

		for (i = 1; i < conn->c_npaths; i++) {

		for (i = 0; i < conn->c_npaths; i++) {

			cp = &conn->c_path[i];

			rds_conn_path_connect_if_down(cp);

		}

net/rds/send.c

+6 −8
Original line number Diff line number Diff line
@@ -971,8 +971,6 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm, 
	return ret;

}



static void rds_send_ping(struct rds_connection *conn);



static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)

{

	int hash;
@@ -982,7 +980,7 @@ static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn) 
	else

		hash = RDS_MPATH_HASH(rs, conn->c_npaths);

	if (conn->c_npaths == 0 && hash != 0) {

		rds_send_ping(conn);

		rds_send_ping(conn, 0);



		if (conn->c_npaths == 0) {

			wait_event_interruptible(conn->c_hs_waitq,
@@ -1282,11 +1280,11 @@ rds_send_pong(struct rds_conn_path *cp, __be16 dport) 
	return rds_send_probe(cp, 0, dport, 0);

}



static void

rds_send_ping(struct rds_connection *conn)

void

rds_send_ping(struct rds_connection *conn, int cp_index)

{

	unsigned long flags;

	struct rds_conn_path *cp = &conn->c_path[0];

	struct rds_conn_path *cp = &conn->c_path[cp_index];



	spin_lock_irqsave(&cp->cp_lock, flags);

	if (conn->c_ping_triggered) {
@@ -1295,6 +1293,6 @@ rds_send_ping(struct rds_connection *conn) 
	}

	conn->c_ping_triggered = 1;

	spin_unlock_irqrestore(&cp->cp_lock, flags);

	rds_send_probe(&conn->c_path[0], cpu_to_be16(RDS_FLAG_PROBE_PORT),

		       0, 0);

	rds_send_probe(cp, cpu_to_be16(RDS_FLAG_PROBE_PORT), 0, 0);

}

EXPORT_SYMBOL_GPL(rds_send_ping);

net/rds/tcp_listen.c

+2 −0
Original line number Diff line number Diff line
@@ -192,6 +192,8 @@ int rds_tcp_accept_one(struct socket *sock) 
	}

	new_sock = NULL;

	ret = 0;

	if (conn->c_npaths == 0)

		rds_send_ping(cp->cp_conn, cp->cp_index);

	goto out;

rst_nsk:

	/* reset the newly returned accept sock and bail.

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