From fe189c2299ec811e2c1e7f4a16482defced52b57 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Wed, 7 Nov 2007 13:51:35 +0100
Subject: [PATCH] --- yaml --- r: 73345 b: refs/heads/master c:
 0e7be9edb9134f833278c381b6feabb54b875208 h: refs/heads/master i:   73343:
 0e75578b3b44ddffd06621ff373cafc93821660b v: v3

---
 [refs]                    |  2 +-
 trunk/block/cfq-iosched.c | 28 +++++++++++++++++-----------
 2 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/[refs] b/[refs]
index 1f9277be23ca..e3222ce795f2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b70c864d3ce706571d2f3cac1d35d4fba01d6072
+refs/heads/master: 0e7be9edb9134f833278c381b6feabb54b875208
diff --git a/trunk/block/cfq-iosched.c b/trunk/block/cfq-iosched.c
index 6831a758d541..0b4a47905575 100644
--- a/trunk/block/cfq-iosched.c
+++ b/trunk/block/cfq-iosched.c
@@ -789,6 +789,20 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
 		__cfq_slice_expired(cfqd, cfqq, timed_out);
 }
 
+static int start_idle_class_timer(struct cfq_data *cfqd)
+{
+	unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
+	unsigned long now = jiffies;
+
+	if (time_before(now, end) &&
+	    time_after_eq(now, cfqd->last_end_request)) {
+		mod_timer(&cfqd->idle_class_timer, end);
+		return 1;
+	}
+
+	return 0;
+}
+
 /*
  * Get next queue for service. Unless we have a queue preemption,
  * we'll simply select the first cfqq in the service tree.
@@ -805,19 +819,14 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
 	cfqq = rb_entry(n, struct cfq_queue, rb_node);
 
 	if (cfq_class_idle(cfqq)) {
-		unsigned long end;
-
 		/*
 		 * if we have idle queues and no rt or be queues had
 		 * pending requests, either allow immediate service if
 		 * the grace period has passed or arm the idle grace
 		 * timer
 		 */
-		end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-		if (time_before(jiffies, end)) {
-			mod_timer(&cfqd->idle_class_timer, end);
+		if (start_idle_class_timer(cfqd))
 			cfqq = NULL;
-		}
 	}
 
 	return cfqq;
@@ -2036,17 +2045,14 @@ static void cfq_idle_slice_timer(unsigned long data)
 static void cfq_idle_class_timer(unsigned long data)
 {
 	struct cfq_data *cfqd = (struct cfq_data *) data;
-	unsigned long flags, end;
+	unsigned long flags;
 
 	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
 
 	/*
 	 * race with a non-idle queue, reset timer
 	 */
-	end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-	if (!time_after_eq(jiffies, end))
-		mod_timer(&cfqd->idle_class_timer, end);
-	else
+	if (!start_idle_class_timer(cfqd))
 		cfq_schedule_dispatch(cfqd);
 
 	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);