Messages in this thread | | | Date | Fri, 04 Feb 2022 23:45:47 +0800 | From | "Boqun Feng" <> | Subject | Re: [PATCH v2] atomics: fix atomic64_{read_acquire,set_release} fallbacks |
| |
On Fri, Feb 4, 2022, at 7:16 PM, Mark Rutland wrote: > On Fri, Feb 04, 2022 at 08:20:25AM +0800, Boqun Feng wrote: >> 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. > > Correct -- those aren't necessary, but aren't harmful, and it's simpler to have > than than it is to special-case the scripts. > >> If so, it's better to mention this somewhere. > > Sure; how about I add the following to the commit message: > > | Since the fallback templates are used to generate the atomic64_*() and > | atomic_*() operations, the __native_word() check is added to both. For > | the atomic_*() operations, which are always 32-bit, the __native_word() > | check is redundant but not harmful, as it is always true. > > ... ? >
Looks good to me!
Regards, Boqun
> Thanks, > Mark.
| |