On Sun, May 31, 2020 at 4:11 AM Syed Nayyar Waris <syednwaris@xxxxxxxxx> wrote: > On Sat, May 30, 2020 at 2:50 PM Andy Shevchenko > <andy.shevchenko@xxxxxxxxx> wrote: > > On Sat, May 30, 2020 at 11:45 AM Syed Nayyar Waris <syednwaris@xxxxxxxxx> wrote: > > > On Sat, May 30, 2020 at 3:49 AM Andy Shevchenko > > > <andy.shevchenko@xxxxxxxxx> wrote: ... > #if (l) == 0 > #define GENMASK_INPUT_CHECK(h, l) 0 > #elif > #define GENMASK_INPUT_CHECK(h, l) \ > (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \ > __builtin_constant_p((l) > (h)), (l) > (h), 0))) > #endif > > I have verified that this works. Basically this just avoids the sanity > check when the 'lower' bound 'l' is zero. Let me know if it looks > fine. Unfortunately, it's not enough. We need to take care about the following cases 1) h or l negative; 2) h == 0, if l == 0, I dunno what is this. it's basically either 0 or warning; 3) l == 0; 4) h and l > 0. Now, on top of that (since it's a macro) we have to keep in mind that h and l can be signed and / or unsigned types. And macro shall work for all 4 cases (by type signedess). > Regarding min, max macro that you suggested I am also looking further into it. Since this has been introduced in v5.7 and not only your code is affected by this I think we need to ping original author either to fix or revert. So, I Cc'ed to the author and reviewers, because they probably know better why that had been done in the first place and breaking existing code. -- With Best Regards, Andy Shevchenko
