* [PATCH] timekeeping: improve arithmetic divisions
@ 2020-01-03 15:55 Wen Yang
0 siblings, 0 replies; only message in thread
From: Wen Yang @ 2020-01-03 15:55 UTC (permalink / raw)
To: John Stultz, Thomas Gleixner, Stephen Boyd; +Cc: Wen Yang, linux-kernel
do_div() does a 64-by-32 division. Use div64_u64()
instead of do_div() if the divisor is u64,
to avoid truncation to 32-bit.
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-kernel@vger.kernel.org
---
kernel/time/timekeeping.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index ca69290..bad76c1 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1007,7 +1007,7 @@ static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
tmp *= mult;
rem *= mult;
- do_div(rem, div);
+ rem = div64_u64(rem, div);
*base = tmp + rem;
return 0;
}
--
1.8.3.1
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