From 75b5ab134bb5f657ef7979a59106dce0657e8d87 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 5 Mar 2024 15:12:47 -0700 Subject: [PATCH] kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 Clang enables -Wenum-enum-conversion and -Wenum-compare-conditional under -Wenum-conversion. A recent change in Clang strengthened these warnings and they appear frequently in common builds, primarily due to several instances in common headers but there are quite a few drivers that have individual instances as well. include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion] 508 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS + | ~~~~~~~~~~~~~~~~~~~~~ ^ 509 | item]; | ~~~~ drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:955:24: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional] 955 | flags |= is_new_rate ? IWL_MAC_BEACON_CCK | ^ ~~~~~~~~~~~~~~~~~~ 956 | : IWL_MAC_BEACON_CCK_V1; | ~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:1120:21: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional] 1120 | 0) > 10 ? | ^ 1121 | IWL_MAC_BEACON_FILS : | ~~~~~~~~~~~~~~~~~~~ 1122 | IWL_MAC_BEACON_FILS_V1; | ~~~~~~~~~~~~~~~~~~~~~~ Doing arithmetic between or returning two different types of enums could be a bug, so each of the instance of the warning needs to be evaluated. Unfortunately, as mentioned above, there are many instances of this warning in many different configurations, which can break the build when CONFIG_WERROR is enabled. To avoid introducing new instances of the warnings while cleaning up the disruption for the majority of users, disable these warnings for the default build while leaving them on for W=1 builds. Cc: stable@vger.kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2002 Link: https://github.com/llvm/llvm-project/commit/8c2ae42b3e1c6aa7c18f873edcebff7c0b45a37e Acked-by: Yonghong Song Signed-off-by: Nathan Chancellor Acked-by: Arnd Bergmann Signed-off-by: Masahiro Yamada --- scripts/Makefile.extrawarn | 2 ++ 1 file changed, 2 insertions(+) diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index a9e552a1e910..2f25a1de129d 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -132,6 +132,8 @@ KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) +KBUILD_CFLAGS += -Wno-enum-compare-conditional +KBUILD_CFLAGS += -Wno-enum-enum-conversion endif endif