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

The RDS handshake ping probe added by commit 5916e2c155
("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: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Tested-by: Jenny Xu <jenny.x.xu@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
zero-colors
Sowmini Varadhan 2017-06-21 13:40:12 -07:00 committed by David S. Miller
parent 6d65923765
commit 69b92b5b74
4 changed files with 12 additions and 11 deletions
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1
net/rds/rds.h
View File

@ -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 */

6
net/rds/recv.c
View File

@ -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);
}

14
net/rds/send.c
View File

@ -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);

2
net/rds/tcp_listen.c
View File

@ -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.