5.15-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Chancellor nathan@kernel.org
commit 8f6629c004b193d23612641c3607e785819e97ab upstream.
-Wenum-enum-conversion was strengthened in clang-19 to warn for C, which caused the kernel to move it to W=1 in commit 75b5ab134bb5 ("kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1") because there were numerous instances that would break builds with -Werror. Unfortunately, this is not a full solution, as more and more developers, subsystems, and distributors are building with W=1 as well, so they continue to see the numerous instances of this warning.
Since the move to W=1, there have not been many new instances that have appeared through various build reports and the ones that have appeared seem to be following similar existing patterns, suggesting that most instances of this warning will not be real issues. The only alternatives for silencing this warning are adding casts (which is generally seen as an ugly practice) or refactoring the enums to macro defines or a unified enum (which may be undesirable because of type safety in other parts of the code).
Move the warning to W=2, where warnings that occur frequently but may be relevant should reside.
Cc: stable@vger.kernel.org Fixes: 75b5ab134bb5 ("kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1") Link: https://lore.kernel.org/ZwRA9SOcOjjLJcpi@google.com/ Signed-off-by: Nathan Chancellor nathan@kernel.org Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- scripts/Makefile.extrawarn | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -37,6 +37,10 @@ KBUILD_CFLAGS += -Wno-missing-field-init KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-type-limits
+ifdef CONFIG_CC_IS_CLANG +KBUILD_CFLAGS += -Wno-enum-enum-conversion +endif + KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1
else @@ -54,7 +58,6 @@ KBUILD_CFLAGS += -Wno-tautological-const 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