Re: [PATCH v2] fs: use acquire ordering in __fget_light()

Jann Horn
2022-10-31T18:14:11Z

On Mon, Oct 31, 2022 at 7:08 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
[...]
> No arch-specific instances, so...
> static __always_inline int
> arch_atomic_read_acquire(const atomic_t *v)
> {
> int ret;
>
> if (__native_word(atomic_t)) {
> ret = smp_load_acquire(&(v)->counter);
> } else {
> ret = arch_atomic_read(v);
> __atomic_acquire_fence();
> }
>
> return ret;
> }
[...]
> Do we really have any architectures where a structure with one
> int field does *not* have a size that would satisfy that check?
>
> Is it future-proofing for masturbation sake, or am I missing something
> real here?

include/linux/atomic/atomic-arch-fallback.h has a comment at the top that says:

// Generated by scripts/atomic/gen-atomic-fallback.sh
// DO NOT MODIFY THIS FILE DIRECTLY