The patch titled
Subject: include/uapi/linux/swab.h: move explicit cast outside ternary
has been added to the -mm mm-nonmm-unstable branch. Its filename is
include-uapi-linux-swabh-move-explicit-cast-outside-ternary.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/include-uapi-linux-swabh-move-explicit-cast-outside-ternary.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Justin Stitt <jstitt007@xxxxxxxxx>
Subject: include/uapi/linux/swab.h: move explicit cast outside ternary
Date: Tue, 7 Jun 2022 17:14:22 -0700
A cast inside __builtin_constant_p doesn't do anything since it should
evaluate as constant at compile time irrespective of this cast. Instead,
I moved this cast outside the ternary to ensure the return type is as
expected.
For instance, if __HAVE_BUILTIN_BSWAP16__ was not defined then __swab16 is
actually returning an `int` not a `u16` due to integer promotion as
described by Nick in this thread. This has repercussions when building
with clang -Wformat. This fix should solve many of these warnings.
Link: https://github.com/ClangBuiltLinux/linux/issues/378
Link: https://lkml.kernel.org/r/20220608001422.26383-1-jstitt007@xxxxxxxxx
Signed-off-by: Justin Stitt <jstitt007@xxxxxxxxx>
Suggested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Suggested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Tom Rix <trix@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/uapi/linux/swab.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/include/uapi/linux/swab.h~include-uapi-linux-swabh-move-explicit-cast-outside-ternary
+++ a/include/uapi/linux/swab.h
@@ -99,10 +99,10 @@ static inline __attribute_const__ __u32
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP16__
-#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
+#define __swab16(x) (__u16)__builtin_bswap16(x)
#else
#define __swab16(x) \
- (__builtin_constant_p((__u16)(x)) ? \
+ (__u16)(__builtin_constant_p(x) ? \
___constant_swab16(x) : \
__fswab16(x))
#endif
@@ -112,10 +112,10 @@ static inline __attribute_const__ __u32
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP32__
-#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
+#define __swab32(x) (__u32)__builtin_bswap32(x)
#else
#define __swab32(x) \
- (__builtin_constant_p((__u32)(x)) ? \
+ (__u32)(__builtin_constant_p(x) ? \
___constant_swab32(x) : \
__fswab32(x))
#endif
@@ -125,10 +125,10 @@ static inline __attribute_const__ __u32
* @x: value to byteswap
*/
#ifdef __HAVE_BUILTIN_BSWAP64__
-#define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
+#define __swab64(x) (__u64)__builtin_bswap64(x)
#else
#define __swab64(x) \
- (__builtin_constant_p((__u64)(x)) ? \
+ (__u64)(__builtin_constant_p(x) ? \
___constant_swab64(x) : \
__fswab64(x))
#endif
_
Patches currently in -mm which might be from jstitt007@xxxxxxxxx are
include-uapi-linux-swabh-move-explicit-cast-outside-ternary.patch
include-uapi-linux-swabh-add-__u16-cast-to-__swab16-conditional.patch
