linux-kernel - [PATCH 21/52] drivers/cpuidle/governors/menu.c: fix undefined reference to `_

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Date:	Thu, 14 Jan 2010 14:27:00 -0800
From:	Greg Kroah-Hartman <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org,
	stable-review@...nel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	Stephen Hemminger <shemminger@...ux-foundation.org>,
	Stephen Hemminger <shemminger@...tta.com>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Len Brown <len.brown@...el.com>,
	Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: [PATCH 21/52] drivers/cpuidle/governors/menu.c: fix undefined reference to `__udivdi3'

From: Stephen Hemminger <shemminger@...ux-foundation.org>

commit 5787536edf18e33d06e2bf038bfd0910f4def213 upstream.

menu: use proper 64 bit math

The new menu governor is incorrectly doing a 64 bit divide.  Compile
tested only

Signed-off-by: Stephen Hemminger <shemminger@...tta.com>
Cc: Arjan van de Ven <arjan@...ux.intel.com>
Cc: Len Brown <len.brown@...el.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
 drivers/cpuidle/governors/menu.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 6810443..73655ae 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -18,6 +18,7 @@
 #include <linux/hrtimer.h>
 #include <linux/tick.h>
 #include <linux/sched.h>
+#include <linux/math64.h>
 
 #define BUCKETS 12
 #define RESOLUTION 1024
@@ -169,6 +170,12 @@ static DEFINE_PER_CPU(struct menu_device, menu_devices);
 
 static void menu_update(struct cpuidle_device *dev);
 
+/* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */
+static u64 div_round64(u64 dividend, u32 divisor)
+{
+	return div_u64(dividend + (divisor / 2), divisor);
+}
+
 /**
  * menu_select - selects the next idle state to enter
  * @dev: the CPU
@@ -209,9 +216,8 @@ static int menu_select(struct cpuidle_device *dev)
 		data->correction_factor[data->bucket] = RESOLUTION * DECAY;
 
 	/* Make sure to round up for half microseconds */
-	data->predicted_us = DIV_ROUND_CLOSEST(
-		data->expected_us * data->correction_factor[data->bucket],
-		RESOLUTION * DECAY);
+	data->predicted_us = div_round64(data->expected_us * data->correction_factor[data->bucket],
+					 RESOLUTION * DECAY);
 
 	/*
 	 * We want to default to C1 (hlt), not to busy polling
-- 
1.6.6

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