| Message ID | 20201128193335.219395-1-masahiroy@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3] Compiler Attributes: remove CONFIG_ENABLE_MUST_CHECK | expand |
On Sun, Nov 29, 2020 at 04:33:35AM +0900, Masahiro Yamada wrote: > Revert commit cebc04ba9aeb ("add CONFIG_ENABLE_MUST_CHECK"). > > A lot of warn_unused_result warnings existed in 2006, but until now > they have been fixed thanks to people doing allmodconfig tests. > > Our goal is to always enable __must_check where appropriate, so this > CONFIG option is no longer needed. > > I see a lot of defconfig (arch/*/configs/*_defconfig) files having: > > # CONFIG_ENABLE_MUST_CHECK is not set > > I did not touch them for now since it would be a big churn. If arch > maintainers want to clean them up, please go ahead. > > While I was here, I also moved __must_check to compiler_attributes.h > from compiler_types.h > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> Acked-by: Nathan Chancellor <natechancellor@gmail.com>
On Sat, Nov 28, 2020 at 11:34 AM Masahiro Yamada <masahiroy@kernel.org> wrote: > > Revert commit cebc04ba9aeb ("add CONFIG_ENABLE_MUST_CHECK"). > > A lot of warn_unused_result warnings existed in 2006, but until now > they have been fixed thanks to people doing allmodconfig tests. > > Our goal is to always enable __must_check where appropriate, so this > CONFIG option is no longer needed. > > I see a lot of defconfig (arch/*/configs/*_defconfig) files having: > > # CONFIG_ENABLE_MUST_CHECK is not set > > I did not touch them for now since it would be a big churn. If arch > maintainers want to clean them up, please go ahead. > > While I was here, I also moved __must_check to compiler_attributes.h > from compiler_types.h > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > --- > > Changes in v3: > - Fix a typo > > Changes in v2: > - Move __must_check to compiler_attributes.h > > include/linux/compiler_attributes.h | 7 +++++++ > include/linux/compiler_types.h | 6 ------ > lib/Kconfig.debug | 8 -------- > tools/testing/selftests/wireguard/qemu/debug.config | 1 - > 4 files changed, 7 insertions(+), 15 deletions(-) > > diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h > index b2a3f4f641a7..5f3b7edad1a7 100644 > --- a/include/linux/compiler_attributes.h > +++ b/include/linux/compiler_attributes.h > @@ -171,6 +171,13 @@ > */ > #define __mode(x) __attribute__((__mode__(x))) > > +/* > + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warn_005funused_005fresult-function-attribute > + * clang: https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result > + * > + */ > +#define __must_check __attribute__((__warn_unused_result__)) > + > /* > * Optional: only supported since gcc >= 7 > * > diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h > index ac3fa37a84f9..7ef20d1a6c28 100644 > --- a/include/linux/compiler_types.h > +++ b/include/linux/compiler_types.h > @@ -110,12 +110,6 @@ struct ftrace_likely_data { > unsigned long constant; > }; > > -#ifdef CONFIG_ENABLE_MUST_CHECK > -#define __must_check __attribute__((__warn_unused_result__)) > -#else > -#define __must_check > -#endif > - > #if defined(CC_USING_HOTPATCH) > #define notrace __attribute__((hotpatch(0, 0))) > #elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY) > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index c789b39ed527..cb8ef4fd0d02 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -286,14 +286,6 @@ config GDB_SCRIPTS > > endif # DEBUG_INFO > > -config ENABLE_MUST_CHECK > - bool "Enable __must_check logic" > - default y > - help > - Enable the __must_check logic in the kernel build. Disable this to > - suppress the "warning: ignoring return value of 'foo', declared with > - attribute warn_unused_result" messages. > - > config FRAME_WARN > int "Warn for stack frames larger than" > range 0 8192 > diff --git a/tools/testing/selftests/wireguard/qemu/debug.config b/tools/testing/selftests/wireguard/qemu/debug.config > index b50c2085c1ac..fe07d97df9fa 100644 > --- a/tools/testing/selftests/wireguard/qemu/debug.config > +++ b/tools/testing/selftests/wireguard/qemu/debug.config > @@ -1,5 +1,4 @@ > CONFIG_LOCALVERSION="-debug" > -CONFIG_ENABLE_MUST_CHECK=y > CONFIG_FRAME_POINTER=y > CONFIG_STACK_VALIDATION=y > CONFIG_DEBUG_KERNEL=y > -- > 2.27.0 >
On Sat, Nov 28, 2020 at 8:34 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > Revert commit cebc04ba9aeb ("add CONFIG_ENABLE_MUST_CHECK"). > > A lot of warn_unused_result warnings existed in 2006, but until now > they have been fixed thanks to people doing allmodconfig tests. > > Our goal is to always enable __must_check where appropriate, so this > CONFIG option is no longer needed. > > I see a lot of defconfig (arch/*/configs/*_defconfig) files having: > > # CONFIG_ENABLE_MUST_CHECK is not set > > I did not touch them for now since it would be a big churn. If arch > maintainers want to clean them up, please go ahead. > > While I was here, I also moved __must_check to compiler_attributes.h > from compiler_types.h > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> Picked this new version with the Acks etc., plus I moved it within compiler_attributes.h to keep it sorted (it's sorted by the second column, rather than the first). Thanks a lot! Cheers, Miguel
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index b2a3f4f641a7..5f3b7edad1a7 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -171,6 +171,13 @@ */ #define __mode(x) __attribute__((__mode__(x))) +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warn_005funused_005fresult-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result + * + */ +#define __must_check __attribute__((__warn_unused_result__)) + /* * Optional: only supported since gcc >= 7 * diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index ac3fa37a84f9..7ef20d1a6c28 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -110,12 +110,6 @@ struct ftrace_likely_data { unsigned long constant; }; -#ifdef CONFIG_ENABLE_MUST_CHECK -#define __must_check __attribute__((__warn_unused_result__)) -#else -#define __must_check -#endif - #if defined(CC_USING_HOTPATCH) #define notrace __attribute__((hotpatch(0, 0))) #elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c789b39ed527..cb8ef4fd0d02 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -286,14 +286,6 @@ config GDB_SCRIPTS endif # DEBUG_INFO -config ENABLE_MUST_CHECK - bool "Enable __must_check logic" - default y - help - Enable the __must_check logic in the kernel build. Disable this to - suppress the "warning: ignoring return value of 'foo', declared with - attribute warn_unused_result" messages. - config FRAME_WARN int "Warn for stack frames larger than" range 0 8192 diff --git a/tools/testing/selftests/wireguard/qemu/debug.config b/tools/testing/selftests/wireguard/qemu/debug.config index b50c2085c1ac..fe07d97df9fa 100644 --- a/tools/testing/selftests/wireguard/qemu/debug.config +++ b/tools/testing/selftests/wireguard/qemu/debug.config @@ -1,5 +1,4 @@ CONFIG_LOCALVERSION="-debug" -CONFIG_ENABLE_MUST_CHECK=y CONFIG_FRAME_POINTER=y CONFIG_STACK_VALIDATION=y CONFIG_DEBUG_KERNEL=y
Revert commit cebc04ba9aeb ("add CONFIG_ENABLE_MUST_CHECK"). A lot of warn_unused_result warnings existed in 2006, but until now they have been fixed thanks to people doing allmodconfig tests. Our goal is to always enable __must_check where appropriate, so this CONFIG option is no longer needed. I see a lot of defconfig (arch/*/configs/*_defconfig) files having: # CONFIG_ENABLE_MUST_CHECK is not set I did not touch them for now since it would be a big churn. If arch maintainers want to clean them up, please go ahead. While I was here, I also moved __must_check to compiler_attributes.h from compiler_types.h Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> --- Changes in v3: - Fix a typo Changes in v2: - Move __must_check to compiler_attributes.h include/linux/compiler_attributes.h | 7 +++++++ include/linux/compiler_types.h | 6 ------ lib/Kconfig.debug | 8 -------- tools/testing/selftests/wireguard/qemu/debug.config | 1 - 4 files changed, 7 insertions(+), 15 deletions(-)