Messages in this thread | | | From | Masahiro Yamada <> | Date | Sun, 4 Aug 2019 15:45:16 +0900 | Subject | Re: [PATCH] linux/bits.h: Add compile time sanity check of GENMASK inputs |
| |
On Sun, Aug 4, 2019 at 3:36 AM Rikard Falkeborn <rikard.falkeborn@gmail.com> wrote: > > On Sat, Aug 03, 2019 at 12:12:46PM +0900, Masahiro Yamada wrote: > > On Sat, Aug 3, 2019 at 12:03 PM Masahiro Yamada > > <yamada.masahiro@socionext.com> wrote: > > > > > > > > BTW, v2 is already inconsistent. > > > If you wanted GENMASK_INPUT_CHECK() to return 'unsigned long',, > > > you would have to cast (low) > (high) as well: > > > > > > (unsigned long)((low) > (high)), UL(0)))) > > > > > > This is totally redundant, and weird. > > > > I take back this comment. > > You added (unsigned long) to the beginning of this macro. > > So, the type is consistent, but I believe all casts should be removed. > > Maybe you're right. BUILD_BUG_ON_ZERO returns size_t regardless of > inputs. I was worried that on some platform, size_t would be larger than > unsigned long (as far as I could see, the standard does not give any > guarantees), and thus all of a sudden GENMASK would be 8 bytes instead > of 4, but perhaps that is not a problem?
How about adding (int) cast to BUILD_BUG_ON_ZERO() ?
-- Best Regards Masahiro Yamada
| |