From: Gary Guo <gary@garyguo.net>
To: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: rust-for-linux@vger.kernel.org, "Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] rust: types: implement `ForeignOwnable` for `Arc<T>`
Date: Fri, 27 Jan 2023 14:04:16 +0000 [thread overview]
Message-ID: <20230127140416.2542ce0a.gary@garyguo.net> (raw)
In-Reply-To: <20230119174036.64046-5-wedsonaf@gmail.com>
On Thu, 19 Jan 2023 14:40:36 -0300
Wedson Almeida Filho <wedsonaf@gmail.com> wrote:
> This allows us to hand ownership of Rust ref-counted objects to
> the C side of the kernel.
>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
> ---
> rust/kernel/sync/arc.rs | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index ff73f9240ca1..519a6ec43644 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -15,7 +15,11 @@
> //!
> //! [`Arc`]: https://doc.rust-lang.org/std/sync/struct.Arc.html
>
> -use crate::{bindings, error::Result, types::Opaque};
> +use crate::{
> + bindings,
> + error::Result,
> + types::{ForeignOwnable, Opaque},
> +};
> use alloc::boxed::Box;
> use core::{
> marker::{PhantomData, Unsize},
> @@ -189,6 +193,32 @@ impl<T: ?Sized> Arc<T> {
> }
> }
>
> +impl<T: 'static> ForeignOwnable for Arc<T> {
> + type Borrowed<'a> = ArcBorrow<'a, T>;
> +
> + fn into_foreign(self) -> *const core::ffi::c_void {
> + ManuallyDrop::new(self).ptr.as_ptr() as _
> + }
> +
> + unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> ArcBorrow<'a, T> {
> + // SAFETY: By the safety requirement of this function, we know that `ptr` came from
> + // a previous call to `Arc::into_foreign`.
> + let inner = NonNull::new(ptr as *mut ArcInner<T>).unwrap();
> +
> + // SAFETY: The safety requirements of `from_foreign` ensure that the object remains alive
> + // for the lifetime of the returned value. Additionally, the safety requirements of
> + // `ForeignOwnable::borrow_mut` ensure that no new mutable references are created.
> + unsafe { ArcBorrow::new(inner) }
> + }
> +
> + unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
> + // SAFETY: By the safety requirement of this function, we know that `ptr` came from
> + // a previous call to `Arc::into_foreign`, which owned guarantees that `ptr` is valid and
> + // owns a reference.
> + unsafe { Self::from_inner(NonNull::new(ptr as _).unwrap()) }
> + }
> +}
> +
> impl<T: ?Sized> Deref for Arc<T> {
> type Target = T;
>
next prev parent reply other threads:[~2023-01-27 14:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-19 17:40 [PATCH 1/5] rust: types: introduce `ScopeGuard` Wedson Almeida Filho
2023-01-19 17:40 ` [PATCH 2/5] rust: types: introduce `ForeignOwnable` Wedson Almeida Filho
2023-01-20 19:59 ` Boqun Feng
2023-01-22 6:34 ` Wedson Almeida Filho
2023-01-27 13:55 ` Gary Guo
2023-01-30 5:59 ` Wedson Almeida Filho
2023-01-28 10:42 ` Vincenzo Palazzo
2023-01-28 14:53 ` Martin Rodriguez Reboredo
2023-01-28 17:05 ` Boqun Feng
2023-01-28 20:46 ` Martin Rodriguez Reboredo
2023-01-28 22:07 ` Boqun Feng
2023-01-29 3:52 ` Martin Rodriguez Reboredo
2023-01-19 17:40 ` [PATCH 3/5] rust: types: implement `ForeignOwnable` for `Box<T>` Wedson Almeida Filho
2023-01-27 13:56 ` Gary Guo
2023-01-28 10:50 ` Vincenzo Palazzo
2023-01-30 5:33 ` Alice Ferrazzi
2023-01-19 17:40 ` [PATCH 4/5] rust: types: implement `ForeignOwnable` for the unit type Wedson Almeida Filho
2023-01-27 14:03 ` Gary Guo
2023-01-27 14:11 ` Miguel Ojeda
2023-01-28 11:13 ` Vincenzo Palazzo
2023-01-30 17:21 ` Miguel Ojeda
2023-01-30 5:55 ` Wedson Almeida Filho
2023-01-28 11:14 ` Vincenzo Palazzo
2023-01-19 17:40 ` [PATCH 5/5] rust: types: implement `ForeignOwnable` for `Arc<T>` Wedson Almeida Filho
2023-01-27 14:04 ` Gary Guo [this message]
2023-01-28 11:15 ` Vincenzo Palazzo
2023-01-30 5:35 ` Alice Ferrazzi
2023-01-20 6:23 ` [PATCH 1/5] rust: types: introduce `ScopeGuard` Boqun Feng
2023-01-22 6:31 ` Wedson Almeida Filho
2023-01-28 10:38 ` Vincenzo Palazzo
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