Re: [PATCH 0/4] Re-export Zeroable and zeroed() from ffi module

[Gary Guo]

On Mon Jan 26, 2026 at 4:08 PM GMT, Benno Lossin wrote:
> On Mon Jan 26, 2026 at 2:25 PM CET, Alice Ryhl wrote:
>> On Mon, Jan 26, 2026 at 01:15:53PM +0000, Gary Guo wrote:
>>> On Mon Jan 26, 2026 at 1:05 PM GMT, Alice Ryhl wrote:
>>> > Currently, the Zeroable trait is defined by pin-init because pin-init
>>> > happens to use the trait. However, zeroed types are useful for many
>>> > purposes other than pin-init. Also, we wish to implement Zeroable for
>>> > types generated by bindgen. For both of these reasons, re-export
>>> > Zeroable from the ffi crate, which is a already dependency of the crates
>>> > with bindgen output.
>>> 
>>> I don't see a benefit of re-exporting these from the `ffi` crate? Especially
>>> that we re-export `ffi` crate from kernel crate anyway, and `Zeroable` is
>>> already in the kernel prelude.
>>> 
>>> We already derive `Zeroable` for bindgen via `MaybeZeroable` derive in
>>> rust/bindgen_parameters.
>>
>> I can't find the convo now, but this change is on my list from when we
>> discussed also implementing FromBytes / IntoBytes for the bindings
>> types. To do that, we need to move our FromBytes / IntoBytes traits
>> somewhere that bindings/uapi can access, and we agreed that the ffi
>> crate was a good place for it.
>>
>> And then for consistency, also reexport Zeroable from the same location.
>
> I think you also mentioned at some point that using `pin_init` from
> `bindings` seemed strange and also using the `pin_init::zeroed()`
> function also doesn't fit, since it doesn't have to do with pinned
> initialization.

Shouldn't it be that a crate that implements Zeroable / FromBytes / IntoBytes
and then pin_init becoming an user of that crate, then?

Best,
Gary