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 26b9168..8a6eaf7 100644 (file)
--- 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,