sctp: improve the code for pmtu probe send and recv update

This patch does 3 things:

  - make sctp_transport_pl_send() and sctp_transport_pl_recv()
    return bool type to decide if more probe is needed to send.

  - pr_debug() only when probe is really needed to send.

  - count pl.raise_count in sctp_transport_pl_send() instead of
    sctp_transport_pl_recv(), and it's only incremented for the
    1st probe for the same size.

These are preparations for the next patch to make probes happen
only when there's packet loss in Search Complete state.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 8 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 09a8f23ec709..32df65f68c12 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1109,12 +1109,12 @@ enum sctp_disposition sctp_sf_send_probe(struct net *net,
 	if (!sctp_transport_pl_enabled(transport))
 		return SCTP_DISPOSITION_CONSUME;
 
-	sctp_transport_pl_send(transport);
-
-	reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
-	if (!reply)
-		return SCTP_DISPOSITION_NOMEM;
-	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	if (sctp_transport_pl_send(transport)) {
+		reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
+		if (!reply)
+			return SCTP_DISPOSITION_NOMEM;
+		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
+	}
 	sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
 			SCTP_TRANSPORT(transport));
 
@@ -1274,8 +1274,7 @@ enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
 		    !sctp_transport_pl_enabled(link))
 			return SCTP_DISPOSITION_DISCARD;
 
-		sctp_transport_pl_recv(link);
-		if (link->pl.state == SCTP_PL_COMPLETE)
+		if (sctp_transport_pl_recv(link))
 			return SCTP_DISPOSITION_CONSUME;
 
 		return sctp_sf_send_probe(net, ep, asoc, type, link, commands);