[13/86] linux/build_bug.h: change type to int

Commit Message

Andrew Morton Dec. 5, 2019, 12:50 a.m. UTC

From: Rikard Falkeborn <[e-mail]>
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/[e-mail]
Signed-off-by: Rikard Falkeborn <[e-mail]>
Suggested-by: Masahiro Yamada <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Masahiro Yamada <[e-mail]>
Cc: Joe Perches <[e-mail]>
Cc: Johannes Berg <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/build_bug.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch

--- 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 */