Re: [PATCH v7 3/3] rust: platform: allow ioremap of platform resources

[Danilo Krummrich <dakr@kernel.org>]

On Wed, Mar 19, 2025 at 12:48:00AM +0000, Benno Lossin wrote:
> On Tue Mar 18, 2025 at 7:22 PM CET, Daniel Almeida wrote:
> > On 18 Mar 2025, at 14:43, Danilo Krummrich <dakr@kernel.org> wrote:
> >> On Tue, Mar 18, 2025 at 02:20:43PM -0300, Daniel Almeida wrote:
> >>> +    ///     // Read and write a 32-bit value at `offset`. Calling `try_access()` on
> >>> +    ///     // the `Devres` makes sure that the resource is still valid.
> >>> +    ///     let data = iomem.try_access().ok_or(ENODEV)?.readl(offset);
> >>> +    ///
> >>> +    ///     iomem.try_access().ok_or(ENODEV)?.writel(data, offset);
> >> 
> >> I'd probably write this as
> >> 
> >> || -> Result {
> >> let iomem = iomem.try_access().ok_or(ENODEV)?;
> >> 
> >> iomem.read32(offset);
> >> iomem.write32(data, offset);
> >> 
> >> Ok(())
> >> }()?;
> 
> Why use a closure here?

Calling try_access() only once and not having the closure is fine too.

But I also think it would be good practice for an example to explicitly limit
the scope of the corresponding guard.

Ideally, it uses [1], once available.

[1] https://lore.kernel.org/rust-for-linux/20250313-try_with-v1-1-adcae7ed98a9@nvidia.com/