Re: [PATCH v7 05/10] rust: io: add IoLoc and IoWrite types

["Danilo Krummrich" <dakr@kernel.org>]

On Mon Mar 2, 2026 at 1:53 PM CET, Gary Guo wrote:
> On Mon Mar 2, 2026 at 1:44 AM GMT, Alexandre Courbot wrote:
>> That should be doable. Note that we currently support `zeroed` and
>> `default` as initializers, so having the same level of coverage would
>> require two `write` variants. I'd like to hear what Danilo thinks.
>
> I wonder if just providing a single version that starts with
> `Default::default()` should be sufficient? For most users, zeroed version is the
> default version anyway. For those where default is not zero, it perhaps makes
> more sense to start with default anyway; if explicitly zeroing is needed they
> can always do an explicit `::zeroed()`.

I was thinking about this for a while and also thought that we probably only
ever need a version that starts with Default::default().

What I still dislike is that the common case becomes write_with() instead of
just write(). (Just to clarify, the name write_with() is perfectly fine for what
the function does, it's more that we need it in the first place.)

Also, IIUC, if the value is not created within the closure, we'd still have the
following redundancy, right?

	let reg = regs::NV_PFALCON_FALCON_DMATRFMOFFS::of::<E>()
		.try_init(|r| r.try_with_offs(load_offsets.dst_start + pos))?;

	bar.write(regs::NV_PFALCON_FALCON_DMATRFMOFFS::of::<E>(), reg);

It's just that this case nicely converts to write_with().