Re: [PATCH 0/1] MR297: vkd3d: Fix invalid atomic behaviour in the view cache linked list.

[Giovanni Mascellani (＠giomasce)]

Giovanni Mascellani (@giomasce) commented about libs/vkd3d/resource.c:
> +static inline bool atomic_compare_exchange_desc_object_address(union desc_object_address volatile *head,
> -
>    union desc_object_address cmp, union desc_object_address xchg, struct vkd3d_desc_object_cache *cache)
>
> +{
> +#ifdef __x86_64__
> - if (cache->have_128_bit_atomics)
> -
>    return vkd3d_atomic_compare_exchange_128(&head->value, cmp.value, xchg.value);
> - else
> -
>    return vkd3d_atomic_compare_exchange_pointer(&head->address.u.object, cmp.address.u.object,
> -
>            xchg.address.u.object);
>
> +#elif defined(__APPLE__)
> - /* TODO: solve ABA problem. */
> - return vkd3d_atomic_compare_exchange_pointer(&head->address.u.object, cmp.address.u.object,
> -
>        xchg.address.u.object);
>
> +#else
> - return vkd3d_atomic_compare_exchange_64(&head->value, cmp.value, xchg.value);
>
> +#endif /* __x86_64__ */

Hmm, I think this leaves all non-x86_64 architectures broken, and x86_64 too in case `cmpxchg16b` is not supported. I think for these cases we should fallback to guarding the linked list with a mutex.