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Date: Tue, 10 Feb 2026 17:45:20 +0100
From: Daniel Gomez <da.gomez@kernel.org>
To: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Tamir Duberstein <tamird@gmail.com>, Miguel Ojeda <ojeda@kernel.org>, 
	Alex Gaynor <alex.gaynor@gmail.com>, Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>, 
	=?utf-8?B?QmrDtnJu?= Roy Baron <bjorn3_gh@protonmail.com>, Benno Lossin <lossin@kernel.org>, 
	Alice Ryhl <aliceryhl@google.com>, Trevor Gross <tmgross@umich.edu>, 
	Danilo Krummrich <dakr@kernel.org>, Lorenzo Stoakes <lorenzo.stoakes@oracle.com>, 
	"Liam R. Howlett" <Liam.Howlett@oracle.com>, Vlastimil Babka <vbabka@suse.cz>, 
	Andrew Morton <akpm@linux-foundation.org>, Christoph Lameter <cl@gentwo.org>, 
	David Rientjes <rientjes@google.com>, Roman Gushchin <roman.gushchin@linux.dev>, 
	Harry Yoo <harry.yoo@oracle.com>, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-mm@kvack.org
Subject: Re: [PATCH v3 02/12] rust: xarray: add debug format for `StoreError`
Message-ID: <aYr-gyQN_AaIJkSH@macos>
References: <20260209-xarray-entry-send-v3-0-f777c65b8ae2@kernel.org>
 <20260209-xarray-entry-send-v3-2-f777c65b8ae2@kernel.org>
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In-Reply-To: <20260209-xarray-entry-send-v3-2-f777c65b8ae2@kernel.org>

On 2026-02-09 15:38, Andreas Hindborg wrote:
> Add a `Debug` implementation for `StoreError<T>` to enable better error
> reporting and debugging. The implementation only displays the `error`
> field and omits the `value` field, as `T` may not implement `Debug`.
> 
> Reviewed-by: Gary Guo <gary@garyguo.net>
> Acked-by: Tamir Duberstein <tamird@gmail.com>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
>  rust/kernel/xarray.rs | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
> index 88625c9abf4ef..d9762c6bef19c 100644
> --- a/rust/kernel/xarray.rs
> +++ b/rust/kernel/xarray.rs
> @@ -193,6 +193,14 @@ pub struct StoreError<T> {
>      pub value: T,
>  }
>  
> +impl<T> core::fmt::Debug for StoreError<T> {
> +    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
> +        f.debug_struct("StoreError")
> +            .field("error", &self.error)
> +            .finish()
> +    }
> +}
> +

Is there any best practice for when to include use core::fmt::*, so you can
avoid being verbose here?

I see other cases like this, but I couldn't find anything in the code
guidelines.

Reviewed-by: Daniel Gomez <da.gomez@samsung.com>