The patch titled
Subject: linux/build_bug.h: change type to int
has been added to the -mm tree. Its filename is
linux-build_bugh-change-type-to-int.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/linux-build_bugh-change-type-to-int.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/linux-build_bugh-change-type-to-int.patch
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------------------------------------------------------
From: Rikard Falkeborn <rikard.falkeborn@xxxxxxxxx>
Subject: linux/build_bug.h: change type to int
Having BUILD_BUG_ON_ZERO produce a value of type size_t leads to awkward
casts in cases where the result needs to be signed, or of smaller type
than size_t. To avoid this, cast the value to int instead and rely on
implicit type conversions when a larger or unsigned type is needed.
Link: http://lkml.kernel.org/r/20190811184938.1796-3-rikard.falkeborn@xxxxxxxxx
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@xxxxxxxxx>
Suggested-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/build_bug.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/build_bug.h~linux-build_bugh-change-type-to-int
+++ a/include/linux/build_bug.h
@@ -9,11 +9,11 @@
#else /* __CHECKER__ */
/*
* Force a compilation error if condition is true, but also produce a
- * result (of value 0 and type size_t), so the expression can be used
+ * result (of value 0 and type int), so the expression can be used
* e.g. in a structure initializer (or where-ever else comma expressions
* aren't permitted).
*/
-#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:(-!!(e)); }))
+#define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
#endif /* __CHECKER__ */
/* Force a compilation error if a constant expression is not a power of 2 */
_
Patches currently in -mm which might be from rikard.falkeborn@xxxxxxxxx are
linux-build_bugh-change-type-to-int.patch
linux-bitsh-add-compile-time-sanity-check-of-genmask-inputs.patch
