[patch 103/166] sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING

Andrew Morton
2020-04-07T03:09:33Z

From: Masahiro Yamada <masahiroy@kernel.org>
Subject: sparc,x86: vdso: remove meaningless undefining CONFIG_OPTIMIZE_INLINING

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.

Link: http://lkml.kernel.org/r/20200220110807.32534-1-masahiroy@kernel.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

arch/sparc/vdso/vdso32/vclock_gettime.c | 4 ----
arch/x86/entry/vdso/vdso32/vclock_gettime.c | 4 ----
2 files changed, 8 deletions(-)

--- a/arch/sparc/vdso/vdso32/vclock_gettime.c~sparcx86-vdso-remove-meaningless-undefining-config_optimize_inlining
+++ a/arch/sparc/vdso/vdso32/vclock_gettime.c
@@ -4,10 +4,6 @@

#define BUILD_VDSO32

-#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
-#undef CONFIG_OPTIMIZE_INLINING
-#endif
-
#ifdef CONFIG_SPARC64

/*
--- a/arch/x86/entry/vdso/vdso32/vclock_gettime.c~sparcx86-vdso-remove-meaningless-undefining-config_optimize_inlining
+++ a/arch/x86/entry/vdso/vdso32/vclock_gettime.c
@@ -1,10 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#define BUILD_VDSO32

-#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
-#undef CONFIG_OPTIMIZE_INLINING
-#endif
-
#ifdef CONFIG_X86_64

/*
_