From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Lobakin Date: Tue, 07 Jun 2022 11:03:10 +0000 Subject: Re: [PATCH 4/6] bitops: unify non-atomic bitops prototypes across architectures Message-Id: <20220607110310.72649-1-alexandr.lobakin@intel.com> List-Id: References: <20220606114908.962562-1-alexandr.lobakin@intel.com> <20220606114908.962562-5-alexandr.lobakin@intel.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Yury Norov Cc: Alexander Lobakin , Arnd Bergmann , Andy Shevchenko , Richard Henderson , Matt Turner , Brian Cain , Geert Uytterhoeven , Yoshinori Sato , Rich Felker , "David S. Miller" , Kees Cook , "Peter Zijlstra (Intel)" , Marco Elver , Borislav Petkov , Tony Luck , Greg Kroah-Hartman , linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org From: Yury Norov Date: Mon, 6 Jun 2022 13:48:50 -0700 > On Mon, Jun 06, 2022 at 01:49:05PM +0200, Alexander Lobakin wrote: > > Currently, there is a mess with the prototypes of the non-atomic > > bitops across the different architectures: > > > > ret bool, int, unsigned long > > nr int, long, unsigned int, unsigned long > > addr volatile unsigned long *, volatile void * > > > > Thankfully, it doesn't provoke any bugs, but can sometimes make > > the compiler angry when it's not handy at all. > > Adjust all the prototypes to the following standard: > > > > ret bool retval can be only 0 or 1 > > nr unsigned long native; signed makes no sense > > addr volatile unsigned long * bitmaps are arrays of ulongs > > > > Finally, add some static assertions in order to prevent people from > > making a mess in this room again. > > I also used the %__always_inline attribute consistently they always > > get resolved to the actual operations. > > > > Suggested-by: Andy Shevchenko > > Signed-off-by: Alexander Lobakin > > --- > > Reviewed-by: Yury Norov > > [...] > > > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > > index 7aaed501f768..5520ac9b1c24 100644 > > --- a/include/linux/bitops.h > > +++ b/include/linux/bitops.h > > @@ -26,12 +26,25 @@ extern unsigned int __sw_hweight16(unsigned int w); > > extern unsigned int __sw_hweight32(unsigned int w); > > extern unsigned long __sw_hweight64(__u64 w); > > > > +#include > > + > > /* > > * Include this here because some architectures need generic_ffs/fls in > > * scope > > */ > > #include > > > > +/* Check that the bitops prototypes are sane */ > > +#define __check_bitop_pr(name) static_assert(__same_type(name, gen_##name)) > > +__check_bitop_pr(__set_bit); > > +__check_bitop_pr(__clear_bit); > > +__check_bitop_pr(__change_bit); > > +__check_bitop_pr(__test_and_set_bit); > > +__check_bitop_pr(__test_and_clear_bit); > > +__check_bitop_pr(__test_and_change_bit); > > +__check_bitop_pr(test_bit); > > +#undef __check_bitop_pr > > This one is amazing trick! And the series is good overall. Do you want me to > take it in bitmap tree, when it's ready, or you'll move it somehow else? Thanks :) Yeah I'm glad we can use __same_type() (-> __builtin_types_compatible_p()) for functions as well, it simplifies keeping the prototypes unified a lot. I'm fine with either your bitmap tree or Arnd's asm-generic tree, so it was my question which I happily forgot to ask: which of those two is preferred for the series. > > Thanks, > Yury Thanks, Olek