Re: [PATCH v2 1/2] sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING

From: Nathan Chancellor
Date: Thu Feb 20 2020 - 12:42:03 EST

On Thu, Feb 20, 2020 at 08:08:06PM +0900, Masahiro Yamada wrote:
> The code, #undef CONFIG_OPTIMIZE_INLINING, is not working as expected
> because <linux/compiler_types.h> is parsed before vclock_gettime.c
> since 28128c61e08e ("kconfig.h: Include compiler types to avoid missed
> struct attributes").
> Since then, <linux/compiler_types.h> is included really early by
> using the '-include' option. So, you cannot negate the decision of
> <linux/compiler_types.h> in this way.
> You can confirm it by checking the pre-processed code, like this:
> $ make arch/x86/entry/vdso/vdso32/vclock_gettime.i
> There is no difference with/without CONFIG_CC_OPTIMIZE_FOR_SIZE.
> It is about two years since 28128c61e08e. Nobody has reported a
> problem (or, nobody has even noticed the fact that this code is not
> working).
> It is ugly and unreliable to attempt to undefine a CONFIG option from
> C files, and anyway the inlining heuristic is up to the compiler.
> Just remove the broken code.
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>