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Date: Mon, 16 Feb 2026 10:58:30 +0100
Message-Id: <DGGAQ7XIDJ3P.1Q2K9WCC25EH3@kernel.org>
Subject: Re: [PATCH] configfs: rust: add an API for adding default groups
 from C
Cc: "Boqun Feng" <boqun.feng@gmail.com>, "Jens Axboe" <axboe@kernel.dk>,
 "Miguel Ojeda" <ojeda@kernel.org>, "Gary Guo" <gary@garyguo.net>,
 =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>, "Benno Lossin"
 <lossin@kernel.org>, "Alice Ryhl" <aliceryhl@google.com>, "Trevor Gross"
 <tmgross@umich.edu>, "Breno Leitao" <leitao@debian.org>,
 <linux-kernel@vger.kernel.org>, <linux-block@vger.kernel.org>,
 <rust-for-linux@vger.kernel.org>
To: "Andreas Hindborg" <a.hindborg@kernel.org>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20260215-configfs-c-default-groups-v1-1-e967daef6c36@kernel.org>
In-Reply-To: <20260215-configfs-c-default-groups-v1-1-e967daef6c36@kernel.org>

On Sun Feb 15, 2026 at 9:33 PM CET, Andreas Hindborg wrote:
> @@ -259,7 +269,13 @@ pub fn new(
>          name: CString,
>          item_type: &'static ItemType<Group<Data>, Data>,
>          data: impl PinInit<Data, Error>,
> +        default_groups: impl IntoIterator<Item =3D Arc<dyn CDefaultGroup=
>>,
>      ) -> impl PinInit<Self, Error> {
> +        let mut dg =3D KVec::new();
> +        for group in default_groups {
> +            dg.push(group, GFP_KERNEL).unwrap();

We should not panic the kernel on allocation failure.

If you wrap the function body into pin_init::pin_init_scope() you can just =
use
the '?' operator instead.

> +        }
> +
>          try_pin_init!(Self {
>              group <- pin_init::init_zeroed().chain(|v: &mut Opaque<bindi=
ngs::config_group>| {
>                  let place =3D v.get();
> @@ -268,13 +284,28 @@ pub fn new(
>                  unsafe {
>                      bindings::config_group_init_type_name(place, name.ca=
st(), item_type.as_ptr())
>                  };
> +
> +                for default_group in &dg {
> +                    // SAFETY: We keep the default groups alive until `S=
elf` is dropped.
> +                    unsafe { bindings::configfs_add_default_group(defaul=
t_group.group_ptr(), place) }
> +                }
>                  Ok(())
>              }),
>              data <- data,
> +            default_groups: dg,
>          })
>      }
>  }