| Message ID | 20200103155458.21707-1-wenyang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
| Series | kernel/power/snapshot.c: improve arithmetic divisions | expand |
On Fri, Jan 3, 2020 at 4:55 PM Wen Yang <wenyang@linux.alibaba.com> wrote: > > 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> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> > Cc: Len Brown <len.brown@intel.com> > Cc: Pavel Machek <pavel@ucw.cz> > Cc: linux-pm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > --- > kernel/power/snapshot.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > index 26b9168..8a6eaf7 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, > -- Applied as 5.6 material under a new subject ("PM: hibernate: improve arithmetic division in preallocate_highmem_fraction()"), thanks!
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 26b9168..8a6eaf7 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,
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> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/power/snapshot.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)