diff options
| author | ndesaulniers@google.com <ndesaulniers@google.com> | 2023-08-01 15:22:17 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-11 11:53:54 +0200 |
| commit | d2fb0969262c8fefceddb2d027e9867cac2a09bc (patch) | |
| tree | 3c29d09ba14ac2a4964414b90c9f3e0b8280892a | |
| parent | be4d2b4562066f2007789f642bee74b46f726dc4 (diff) | |
word-at-a-time: use the same return type for has_zero regardless of endianness
[ Upstream commit 79e8328e5acbe691bbde029a52c89d70dcbc22f3 ]
Compiling big-endian targets with Clang produces the diagnostic:
fs/namei.c:2173:13: warning: use of bitwise '|' with boolean operands [-Wbitwise-instead-of-logical]
} while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
||
fs/namei.c:2173:13: note: cast one or both operands to int to silence this warning
It appears that when has_zero was introduced, two definitions were
produced with different signatures (in particular different return
types).
Looking at the usage in hash_name() in fs/namei.c, I suspect that
has_zero() is meant to be invoked twice per while loop iteration; using
logical-or would not update `bdata` when `a` did not have zeros. So I
think it's preferred to always return an unsigned long rather than a
bool than update the while loop in hash_name() to use a logical-or
rather than bitwise-or.
[ Also changed powerpc version to do the same - Linus ]
Link: https://github.com/ClangBuiltLinux/linux/issues/1832
Link: https://lore.kernel.org/lkml/20230801-bitwise-v1-1-799bec468dc4@google.com/
Fixes: 36126f8f2ed8 ("word-at-a-time: make the interfaces truly generic")
Debugged-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/powerpc/include/asm/word-at-a-time.h | 2 | ||||
| -rw-r--r-- | include/asm-generic/word-at-a-time.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/word-at-a-time.h b/arch/powerpc/include/asm/word-at-a-time.h index f3f4710d4ff5..99129b0cd8b8 100644 --- a/arch/powerpc/include/asm/word-at-a-time.h +++ b/arch/powerpc/include/asm/word-at-a-time.h @@ -34,7 +34,7 @@ static inline long find_zero(unsigned long mask) return leading_zero_bits >> 3; } -static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) +static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) { unsigned long rhs = val | c->low_bits; *data = rhs; diff --git a/include/asm-generic/word-at-a-time.h b/include/asm-generic/word-at-a-time.h index 20c93f08c993..95a1d214108a 100644 --- a/include/asm-generic/word-at-a-time.h +++ b/include/asm-generic/word-at-a-time.h @@ -38,7 +38,7 @@ static inline long find_zero(unsigned long mask) return (mask >> 8) ? byte : byte + 1; } -static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) +static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c) { unsigned long rhs = val | c->low_bits; *data = rhs; |