From: Wen Yang <wenyang@linux.alibaba.com>
Date: Fri, 3 Jan 2020 15:54:58 +0000 (+0800)
Subject: PM: hibernate: improve arithmetic division in preallocate_highmem_fraction()
X-Git-Tag: block-5.6-2020-02-05~84^2~2^3^2~3
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=809ed78a832df8b4ef81fee03570566c8f088f3a;p=linux-block.git

PM: hibernate: improve arithmetic division in preallocate_highmem_fraction()

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.

This change also cleans up code a tad.

Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 26b9168321e7..8a6eaf7367f3 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1566,9 +1566,7 @@ static unsigned long preallocate_image_highmem(unsigned long nr_pages)
  */
 static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
 {
-	x *= multiplier;
-	do_div(x, base);
-	return (unsigned long)x;
+	return div64_u64(x * multiplier, base);
 }
 
 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,