Messages in this thread Patch in this message | | | Date | Fri, 4 Feb 2022 08:20:25 +0800 | From | Boqun Feng <> | Subject | Re: [PATCH v2] atomics: fix atomic64_{read_acquire,set_release} fallbacks |
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On Thu, Feb 03, 2022 at 04:12:43PM +0000, Mark Rutland wrote: > diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h > index a3dba31df01e..6db58d180866 100644 > --- a/include/linux/atomic/atomic-arch-fallback.h > +++ b/include/linux/atomic/atomic-arch-fallback.h > @@ -151,7 +151,16 @@ > static __always_inline int > arch_atomic_read_acquire(const atomic_t *v) > { > - return smp_load_acquire(&(v)->counter); > + int ret; > + > + if (__native_word(atomic_t)) { > + ret = smp_load_acquire(&(v)->counter); > + } else { > + ret = arch_atomic_read(v); > + __atomic_acquire_fence(); > + } > + > + return ret; > } > #define arch_atomic_read_acquire arch_atomic_read_acquire > #endif > @@ -160,7 +169,12 @@ arch_atomic_read_acquire(const atomic_t *v) > static __always_inline void > arch_atomic_set_release(atomic_t *v, int i) > { > - smp_store_release(&(v)->counter, i); > + if (__native_word(atomic_t)) { > + smp_store_release(&(v)->counter, i); > + } else { > + __atomic_release_fence(); > + arch_atomic_set(v, i); > + } > }
The changes for atomic_t are not necessary, right? They are correct but "side effects" because of the change in scripts. If so, it's better to mention this somewhere.
Regards, Boqun
> #define arch_atomic_set_release arch_atomic_set_release > #endif > @@ -1258,7 +1272,16 @@ arch_atomic_dec_if_positive(atomic_t *v) > static __always_inline s64 > arch_atomic64_read_acquire(const atomic64_t *v) > { > - return smp_load_acquire(&(v)->counter); > + s64 ret; > + > + if (__native_word(atomic64_t)) { > + ret = smp_load_acquire(&(v)->counter); > + } else { > + ret = arch_atomic64_read(v); > + __atomic_acquire_fence(); > + } > + > + return ret; > } > #define arch_atomic64_read_acquire arch_atomic64_read_acquire > #endif > @@ -1267,7 +1290,12 @@ arch_atomic64_read_acquire(const atomic64_t *v) > static __always_inline void > arch_atomic64_set_release(atomic64_t *v, s64 i) > { > - smp_store_release(&(v)->counter, i); > + if (__native_word(atomic64_t)) { > + smp_store_release(&(v)->counter, i); > + } else { > + __atomic_release_fence(); > + arch_atomic64_set(v, i); > + } > } > #define arch_atomic64_set_release arch_atomic64_set_release > #endif > @@ -2358,4 +2386,4 @@ arch_atomic64_dec_if_positive(atomic64_t *v) > #endif > > #endif /* _LINUX_ATOMIC_FALLBACK_H */ > -// cca554917d7ea73d5e3e7397dd70c484cad9b2c4 > +// 8e2cc06bc0d2c0967d2f8424762bd48555ee40ae > diff --git a/scripts/atomic/fallbacks/read_acquire b/scripts/atomic/fallbacks/read_acquire > index 803ba7561076..a0ea1d26e6b2 100755 > --- a/scripts/atomic/fallbacks/read_acquire > +++ b/scripts/atomic/fallbacks/read_acquire > @@ -2,6 +2,15 @@ cat <<EOF > static __always_inline ${ret} > arch_${atomic}_read_acquire(const ${atomic}_t *v) > { > - return smp_load_acquire(&(v)->counter); > + ${int} ret; > + > + if (__native_word(${atomic}_t)) { > + ret = smp_load_acquire(&(v)->counter); > + } else { > + ret = arch_${atomic}_read(v); > + __atomic_acquire_fence(); > + } > + > + return ret; > } > EOF > diff --git a/scripts/atomic/fallbacks/set_release b/scripts/atomic/fallbacks/set_release > index 86ede759f24e..05cdb7f42477 100755 > --- a/scripts/atomic/fallbacks/set_release > +++ b/scripts/atomic/fallbacks/set_release > @@ -2,6 +2,11 @@ cat <<EOF > static __always_inline void > arch_${atomic}_set_release(${atomic}_t *v, ${int} i) > { > - smp_store_release(&(v)->counter, i); > + if (__native_word(${atomic}_t)) { > + smp_store_release(&(v)->counter, i); > + } else { > + __atomic_release_fence(); > + arch_${atomic}_set(v, i); > + } > } > EOF > -- > 2.30.2 > [unhandled content-type:application/pgp-signature] | |