[ 47/89] watchdog: using u64 in get_sample_period()

[Ben Hutchings]

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chuansheng Liu <chuansheng.liu@xxxxxxxxx>

commit 8ffeb9b0e6369135bf03a073514f571ef10606b9 upstream.

In get_sample_period(), unsigned long is not enough:

  watchdog_thresh * 2 * (NSEC_PER_SEC / 5)

case1:
  watchdog_thresh is 10 by default, the sample value will be: 0xEE6B2800

case2:
 set watchdog_thresh is 20, the sample value will be: 0x1 DCD6 5000

In case2, we need use u64 to express the sample period.  Otherwise,
changing the threshold thru proc often can not be successful.

Signed-off-by: liu chuansheng <chuansheng.liu@xxxxxxxxx>
Acked-by: Don Zickus <dzickus@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 kernel/watchdog.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -113,7 +113,7 @@ static unsigned long get_timestamp(int t
 	return cpu_clock(this_cpu) >> 30LL;  /* 2^30 ~= 10^9 */
 }
 
-static unsigned long get_sample_period(void)
+static u64 get_sample_period(void)
 {
 	/*
 	 * convert watchdog_thresh from seconds to ns
@@ -121,7 +121,7 @@ static unsigned long get_sample_period(v
 	 * increment before the hardlockup detector generates
 	 * a warning
 	 */
-	return get_softlockup_thresh() * (NSEC_PER_SEC / 5);
+	return get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5);
 }
 
 /* Commands for resetting the watchdog */


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