From 46db4005895000d3ee97159c349ee6cd1dcf97a5 Mon Sep 17 00:00:00 2001
From: Richard Cochran <richardcochran@gmail.com>
Date: Sun, 14 Jul 2013 21:34:01 +0200
Subject: [PATCH] Become the grand master when all alone.

This patch cleans up the BMC logic to allow assuming the GM role when no
other clocks are found in the network. By allowing the "best" to be NULL,
we can let the BMC to naturally pick the local clock as GM. As an added
bonus, this also get rid of the hacky check for a lost master.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
---
 bmc.c   |  3 ---
 clock.c | 31 ++++++++++++-------------------
 2 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/bmc.c b/bmc.c
index 9d6b1af..462a90d 100644
--- a/bmc.c
+++ b/bmc.c
@@ -133,9 +133,6 @@ enum port_state bmc_state_decision(struct clock *c, struct port *r)
 	if (!port_best && PS_LISTENING == ps)
 		return ps;
 
-	if (!clock_best)
-		return PS_FAULTY;
-
 	if (clock_class(c) <= 127) {
 		if (dscmp(clock_ds, port_best) > 0) {
 			return PS_GRAND_MASTER; /*M1*/
diff --git a/clock.c b/clock.c
index b097911..8dd6662 100644
--- a/clock.c
+++ b/clock.c
@@ -333,16 +333,6 @@ static int clock_management_set(struct clock *c, struct port *p,
 	return respond ? 1 : 0;
 }
 
-static int clock_master_lost(struct clock *c)
-{
-	int i;
-	for (i = 0; i < c->nports; i++) {
-		if (PS_SLAVE == port_state(c->port[i]))
-			return 0;
-	}
-	return 1;
-}
-
 static void clock_stats_update(struct clock_stats *s,
 			       int64_t offset, double freq)
 {
@@ -899,7 +889,7 @@ struct PortIdentity clock_parent_identity(struct clock *c)
 
 int clock_poll(struct clock *c)
 {
-	int cnt, err, i, j, k, lost = 0, sde = 0;
+	int cnt, err, i, j, k, sde = 0;
 	enum fsm_event event;
 
 	cnt = poll(c->pollfd, ARRAY_SIZE(c->pollfd), -1);
@@ -924,7 +914,7 @@ int clock_poll(struct clock *c)
 				if (EV_STATE_DECISION_EVENT == event)
 					sde = 1;
 				if (EV_ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES == event)
-					lost = 1;
+					sde = 1;
 				err = port_dispatch(c->port[i], event, 0);
 				/* Clear any fault after a little while. */
 				if (PS_FAULTY == port_state(c->port[i])) {
@@ -952,8 +942,6 @@ int clock_poll(struct clock *c)
 		}
 	}
 
-	if (lost && clock_master_lost(c))
-		clock_update_grandmaster(c);
 	if (sde)
 		handle_state_decision_event(c);
 
@@ -1144,6 +1132,7 @@ void clock_update_time_properties(struct clock *c, struct timePropertiesDS tds)
 static void handle_state_decision_event(struct clock *c)
 {
 	struct foreign_clock *best = NULL, *fc;
+	struct ClockIdentity best_id;
 	int fresh_best = 0, i;
 
 	for (i = 0; i < c->nports; i++) {
@@ -1154,13 +1143,16 @@ static void handle_state_decision_event(struct clock *c)
 			best = fc;
 	}
 
-	if (!best)
-		return;
+	if (best) {
+		best_id = best->dataset.identity;
+	} else {
+		best_id = c->dds.clockIdentity;
+	}
 
 	pr_notice("selected best master clock %s",
-		cid2str(&best->dataset.identity));
+		  cid2str(&best_id));
 
-	if (!cid_eq(&best->dataset.identity, &c->best_id)) {
+	if (!cid_eq(&best_id, &c->best_id)) {
 		clock_freq_est_reset(c);
 		mave_reset(c->avg_delay);
 		c->path_delay = 0;
@@ -1168,7 +1160,7 @@ static void handle_state_decision_event(struct clock *c)
 	}
 
 	c->best = best;
-	c->best_id = best->dataset.identity;
+	c->best_id = best_id;
 
 	for (i = 0; i < c->nports; i++) {
 		enum port_state ps;
@@ -1179,6 +1171,7 @@ static void handle_state_decision_event(struct clock *c)
 			event = EV_NONE;
 			break;
 		case PS_GRAND_MASTER:
+			pr_notice("assuming the grand master role");
 			clock_update_grandmaster(c);
 			event = EV_RS_GRAND_MASTER;
 			break;