From 1967939462641d8b36bcb3fcf06d48e66cd67a4f Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 29 Nov 2020 04:33:35 +0900
Subject: [PATCH] Compiler Attributes: remove CONFIG_ENABLE_MUST_CHECK
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>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
[Moved addition in compiler_attributes.h to keep it sorted]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
include/linux/compiler_attributes.h | 6 ++++++
include/linux/compiler_types.h | 6 ------
lib/Kconfig.debug | 8 --------
tools/testing/selftests/wireguard/qemu/debug.config | 1 -
4 files changed, 6 insertions(+), 15 deletions(-)
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index b2a3f4f641a7..ea5e04e75845 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -272,6 +272,12 @@
*/
#define __used __attribute__((__used__))
+/*
+ * 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__))
+
/*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute
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
--
2.49.0