From: David Lambert <dave@lambsys.com>
Date: Mon, 7 Mar 2011 10:00:46 +0000 (+0200)
Subject: mtd: speedtest: fix integer overflow
X-Git-Tag: v2.6.39-rc1~40^2~17
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e70727e442eb61581f836a9a0ca0c3b70d8a3ff2;p=karo-tx-linux.git

mtd: speedtest: fix integer overflow

32-bit integers used in 'calc_speed()' may overflow and lead to
incorrect results. Use 64-bit integers instead.

Signed-off-by: David Lambert <dave@lambsys.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---

diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index 3ce6fce75e07..627d4e2466a3 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -314,16 +314,16 @@ static inline void stop_timing(void)
 
 static long calc_speed(void)
 {
-	long ms, k, speed;
+	uint64_t k;
+	long ms;
 
 	ms = (finish.tv_sec - start.tv_sec) * 1000 +
 	     (finish.tv_usec - start.tv_usec) / 1000;
-	k = goodebcnt * mtd->erasesize / 1024;
-	if (ms)
-		speed = (k * 1000) / ms;
-	else
-		speed = 0;
-	return speed;
+	if (ms == 0)
+		return 0;
+	k = goodebcnt * (mtd->erasesize / 1024) * 1000;
+	do_div(k, ms);
+	return k;
 }
 
 static int scan_for_bad_eraseblocks(void)