Re: [PATCH 01/10] locking/atomic: Add missing cast to try_cmpxchg() fallbacks
flat view
From: Mark Rutland <mark.rutland@arm.com>
Date: 2023-03-24 14:13:23
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linux-alpha, linux-arch, linux-mips, linux-perf-users, lkml, loongarch
On Sun, Mar 05, 2023 at 09:56:19PM +0100, Uros Bizjak wrote:
Cast _oldp to the type of _ptr to avoid incompatible-pointer-types warning.
Can you give an example of where we are passing an incompatible pointer? That sounds indicative of a bug in the caller, but maybe I'm missing some reason this is necessary due to some indirection.
Fixes: 29f006fdefe6 ("asm-generic/atomic: Add try_cmpxchg() fallbacks")I'm not sure that this needs a fixes tag. Does anything go wrong today, or only later in this series? Thanks, Mark.
quoted hunk ↗ jump to hunk
Cc: Will Deacon <will@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <redacted> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Uros Bizjak <redacted> --- include/linux/atomic/atomic-arch-fallback.h | 18 +++++++++--------- scripts/atomic/gen-atomic-fallback.sh | 2 +- 2 files changed, 10 insertions(+), 10 deletions(-)diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h index 77bc5522e61c..19debd501ee7 100644 --- a/include/linux/atomic/atomic-arch-fallback.h +++ b/include/linux/atomic/atomic-arch-fallback.h@@ -87,7 +87,7 @@ #ifndef arch_try_cmpxchg #define arch_try_cmpxchg(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -98,7 +98,7 @@ #ifndef arch_try_cmpxchg_acquire #define arch_try_cmpxchg_acquire(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg_acquire((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -109,7 +109,7 @@ #ifndef arch_try_cmpxchg_release #define arch_try_cmpxchg_release(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg_release((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -120,7 +120,7 @@ #ifndef arch_try_cmpxchg_relaxed #define arch_try_cmpxchg_relaxed(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg_relaxed((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -157,7 +157,7 @@ #ifndef arch_try_cmpxchg64 #define arch_try_cmpxchg64(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg64((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -168,7 +168,7 @@ #ifndef arch_try_cmpxchg64_acquire #define arch_try_cmpxchg64_acquire(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg64_acquire((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -179,7 +179,7 @@ #ifndef arch_try_cmpxchg64_release #define arch_try_cmpxchg64_release(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg64_release((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -190,7 +190,7 @@ #ifndef arch_try_cmpxchg64_relaxed #define arch_try_cmpxchg64_relaxed(_ptr, _oldp, _new) \ ({ \ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \ ___r = arch_cmpxchg64_relaxed((_ptr), ___o, (_new)); \ if (unlikely(___r != ___o)) \ *___op = ___r; \@@ -2456,4 +2456,4 @@ arch_atomic64_dec_if_positive(atomic64_t *v) #endif #endif /* _LINUX_ATOMIC_FALLBACK_H */ -// b5e87bdd5ede61470c29f7a7e4de781af3770f09 +// 1b4d4c82ae653389cd1538d5b07170267d9b3837diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen-atomic-fallback.sh index 3a07695e3c89..39f447161108 100755 --- a/scripts/atomic/gen-atomic-fallback.sh +++ b/scripts/atomic/gen-atomic-fallback.sh@@ -171,7 +171,7 @@ cat <<EOF #ifndef arch_try_${cmpxchg}${order} #define arch_try_${cmpxchg}${order}(_ptr, _oldp, _new) \\ ({ \\ - typeof(*(_ptr)) *___op = (_oldp), ___o = *___op, ___r; \\ + typeof(*(_ptr)) *___op = (typeof(_ptr))(_oldp), ___o = *___op, ___r; \\ ___r = arch_${cmpxchg}${order}((_ptr), ___o, (_new)); \\ if (unlikely(___r != ___o)) \\ *___op = ___r; \\-- 2.39.2