From 7607774f30b1440b35cf6a9ae969174895fd0c8c Mon Sep 17 00:00:00 2001
From: Geoff Salmon <gsalmon@se-instruments.com>
Date: Mon, 31 Dec 2012 15:12:54 -0500
Subject: [PATCH] Avoid calling msg_pre_send/post_recv unless actually
 forwarding a message

---
 clock.c | 44 +++++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/clock.c b/clock.c
index 39f378e..5a475f2 100644
--- a/clock.c
+++ b/clock.c
@@ -577,10 +577,36 @@ void clock_install_fda(struct clock *c, struct port *p, struct fdarray fda)
 	}
 }
 
+static void clock_forward_mgmt_msg(struct clock *c, struct port *p, struct ptp_message *msg)
+{
+	int i, pdulen, msg_ready = 0;
+	struct port *fwd;
+	if (forwarding(c, p) && msg->management.boundaryHops) {
+		for (i = 0; i < c->nports + 1; i++) {
+			fwd = c->port[i];
+			if (fwd != p && forwarding(c, fwd)) {
+				/* delay calling msg_pre_send until
+				 * actually forwarding */
+				if (!msg_ready) {
+					msg_ready = 1;
+					pdulen = msg->header.messageLength;
+					msg->management.boundaryHops--;
+					msg_pre_send(msg);
+				}
+				if (port_forward(fwd, msg, pdulen))
+					pr_err("port %d: management forward failed", i);
+			}
+		}
+		if (msg_ready) {
+			msg_post_recv(msg, pdulen);
+			msg->management.boundaryHops++;
+		}
+	}
+}
+
 void clock_manage(struct clock *c, struct port *p, struct ptp_message *msg)
 {
-	int i, pdulen;
-	struct port *fwd;
+	int i;
 	struct management_tlv *mgt;
 	struct PortIdentity pid;
 	struct ClockIdentity *tcid, wildcard = {
@@ -588,19 +614,7 @@ void clock_manage(struct clock *c, struct port *p, struct ptp_message *msg)
 	};
 
 	/* Forward this message out all eligible ports. */
-	if (forwarding(c, p) && msg->management.boundaryHops) {
-		pdulen = msg->header.messageLength;
-		msg->management.boundaryHops--;
-		msg_pre_send(msg);
-		for (i = 0; i < c->nports + 1; i++) {
-			fwd = c->port[i];
-			if (fwd != p && forwarding(c, fwd) &&
-			    port_forward(fwd, msg, pdulen))
-				pr_err("port %d: management forward failed", i);
-		}
-		msg_post_recv(msg, pdulen);
-		msg->management.boundaryHops++;
-	}
+	clock_forward_mgmt_msg(c, p, msg);
 
 	/* Apply this message to the local clock and ports. */
 	tcid = &msg->management.targetPortIdentity.clockIdentity;