From cb6f994ae2e009b95b631fafb86d53f91bac784e Mon Sep 17 00:00:00 2001
From: John Stultz <john.stultz@linaro.org>
Date: Wed, 10 Aug 2011 11:31:03 -0700
Subject: [PATCH] --- yaml --- r: 269183 b: refs/heads/master c:
 dce75a8c71819ed4c7efdcd53c9b6f6356dc8cb5 h: refs/heads/master i:   269181:
 2168f33b91cb753152fe7fd5767e6f608b256924   269179:
 9d694bb20a4b6f8f6eebd397a6cdcc16d21c0287   269175:
 3d136680f4b29d6e6e35a94dc8886dae8c90d0c2   269167:
 1b1695b770eca47d4dccb93fb46406442de99793   269151:
 d0679a7100b30c9da2e7cb9a65b5edb0d09faaf9   269119:
 b1bb01111fae15b563db4fd83f8411665cf7cfc2   269055:
 1a7b06a4e2b8d50267c4e5d2de10674d53b690bb v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/alarmtimer.h |  2 ++
 trunk/kernel/time/alarmtimer.c   | 37 +++++++++++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index ee2da6298ac8..140fde7e5daa 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 54da23b720d5d612f8f1669f9ed3744008fb7382
+refs/heads/master: dce75a8c71819ed4c7efdcd53c9b6f6356dc8cb5
diff --git a/trunk/include/linux/alarmtimer.h b/trunk/include/linux/alarmtimer.h
index 0289eb29e794..17535963b274 100644
--- a/trunk/include/linux/alarmtimer.h
+++ b/trunk/include/linux/alarmtimer.h
@@ -42,4 +42,6 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period);
 void alarm_cancel(struct alarm *alarm);
 
+u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
+
 #endif
diff --git a/trunk/kernel/time/alarmtimer.c b/trunk/kernel/time/alarmtimer.c
index 55e634ea6054..f03b04291b6f 100644
--- a/trunk/kernel/time/alarmtimer.c
+++ b/trunk/kernel/time/alarmtimer.c
@@ -347,6 +347,41 @@ void alarm_cancel(struct alarm *alarm)
 }
 
 
+
+u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
+{
+	u64 overrun = 1;
+	ktime_t delta;
+
+	delta = ktime_sub(now, alarm->node.expires);
+
+	if (delta.tv64 < 0)
+		return 0;
+
+	if (unlikely(delta.tv64 >= interval.tv64)) {
+		s64 incr = ktime_to_ns(interval);
+
+		overrun = ktime_divns(delta, incr);
+
+		alarm->node.expires = ktime_add_ns(alarm->node.expires,
+							incr*overrun);
+
+		if (alarm->node.expires.tv64 > now.tv64)
+			return overrun;
+		/*
+		 * This (and the ktime_add() below) is the
+		 * correction for exact:
+		 */
+		overrun++;
+	}
+
+	alarm->node.expires = ktime_add(alarm->node.expires, interval);
+	return overrun;
+}
+
+
+
+
 /**
  * clock2alarm - helper that converts from clockid to alarmtypes
  * @clockid: clockid.
@@ -376,7 +411,7 @@ static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 
 	/* Re-add periodic timers */
 	if (alarm->period.tv64) {
-		alarm->node.expires = ktime_add(now, alarm->period);
+		ptr->it_overrun += alarm_forward(alarm, now, alarm->period);
 		return ALARMTIMER_RESTART;
 	}
 	return ALARMTIMER_NORESTART;