Re: [PATCH 3/4] rust: serdev: use DropGuard

[Markus Probst <markus.probst@posteo.de>]

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On Sun, 2026-09-27 at 13:45 +0300, Mohamed Osama wrote:
> Replace the ScopeGuard usage in the serial device bus implementation
> with DropGuard.
> 
> Use DropGuard::dismiss() when ownership of the private data needs to be
> transferred without running the cleanup callback.
> 
> Signed-off-by: Mohamed Osama <mohamed.osama189110@gmail.com>
> ---
>  rust/kernel/serdev.rs | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/rust/kernel/serdev.rs b/rust/kernel/serdev.rs
> index 17ca504b7f8d..dd43b159b461 100644
> --- a/rust/kernel/serdev.rs
> +++ b/rust/kernel/serdev.rs
> @@ -13,6 +13,7 @@
>          to_result,
>          VTABLE_DEFAULT_ERROR, //
>      },
> +    mem::DropGuard,
>      new_mutex,
>      of,
>      prelude::*,
> @@ -21,10 +22,7 @@
>          Mutex, //
>      },
>      time::Jiffies,
> -    types::{
> -        Opaque,
> -        ScopeGuard, //
> -    }, //
> +    types::Opaque, //
>  };
>  
>  use core::{
> @@ -174,7 +172,7 @@ extern "C" fn probe_callback(sdev: *mut bindings::serdev_device) -> kernel::ffi:
>              }))?;
>              // SAFETY: We just set drvdata to `PrivateData<'_, T>`.
>              let private_data = unsafe { sdev.as_ref().drvdata_borrow::<PrivateData<'_, T>>() };
> -            let private_data = ScopeGuard::new_with_data(private_data, |_| {
> +            let private_data = DropGuard::new(private_data, |_| {
>                  // SAFETY: We just set drvdata to `PrivateData<'_, T>`.
>                  drop(unsafe { sdev.as_ref().drvdata_obtain::<PrivateData<'_, T>>() });
>              });
> @@ -204,7 +202,7 @@ extern "C" fn probe_callback(sdev: *mut bindings::serdev_device) -> kernel::ffi:
>              drop(active);
>  
>              result.map(|()| {
> -                private_data.dismiss();
> +                DropGuard::dismiss(private_data);
>                  0
>              })
>          })
I am surprised to not find myself on CC. I only look loosly on the
linux-serial mailing list, so please add me to CC.

This patch will be redundant once
https://lore.kernel.org/linux-serial/20260930-rust_serdev_probe_refactor-v3-4-d1b6e77135e0@posteo.de/
get merged. Not sure if it gets merged this cycle though.

Also I am not sure on which base this should be applied to?
Applying to v7.3-rc6 or next-20261009 fails.

Thanks
- Markus Probst





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