Re: [PATCH v3 1/2] rust: uapi: add zerocopy/zerocopy_derive

[Gary Guo]

On Sat Sep 26, 2026 at 10:38 PM BST, Danilo Krummrich wrote:
> On Sat Sep 26, 2026 at 10:59 PM CEST, Gary Guo wrote:
>> On Sat Sep 26, 2026 at 5:26 PM BST, Danilo Krummrich wrote:
>>> On Sat Sep 26, 2026 at 5:50 PM CEST, Gary Guo wrote:
>>>> On Sat Sep 26, 2026 at 1:26 AM BST, Deborah Brouwer wrote:
>>>>> @@ -71,3 +71,6 @@
>>>>>  # Structs should implement `Zeroable` when all of their fields do.
>>>>>  --with-derive-custom-struct .*=MaybeZeroable
>>>>>  --with-derive-custom-union .*=MaybeZeroable
>>>>> +
>>>>> +# `drm_panthor_gpu_info` is copied byte-for-byte to userspace.
>>>>> +--with-derive-custom-struct '^drm_panthor_gpu_info$'=zerocopy_derive::most_traits
>>>>
>>>> This is Tyr specific change and should be in patch 2.
>>>
>>> Why list all of them separately? Can't we apply this to all uAPI structs?
>>
>> There are types with paddings which cannot derive `IntoBytes`.
>
> We have some existing uAPI structs without explicit padding; new ones should use
> explicit padding though.
>
> But isn’t most_traits intended to handle this through best-effort derivation,
> leaving IntoBytes unavailable for types with implicit padding?

I think the skip-on-error default was added in a version newer than what we've
vendored.

Best,
Gary