We have a bugreport which blames div64_u64() on 32bit platforms.
However, the code obviously doesn't even try to pretend it can do
the 64bit division precisely. If there is something in the high
word of divisor, div64_u64() just shifts both arguments and throws
out the low bits.
Add a small comment to avoid the confusion.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
lib/div64.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -77,7 +77,10 @@ s64 div_s64_rem(s64 dividend, s32 diviso
EXPORT_SYMBOL(div_s64_rem);
#endif
-/* 64bit divisor, dividend and result. dynamic precision */
+/*
+ * 64bit divisor, dividend and result. Dynamic precision, unless
+ * divisor fits in u32 result is not exactly correct.
+ */
#ifndef div64_u64
u64 div64_u64(u64 dividend, u64 divisor)
{
--
