lkml.org 
[lkml]   [2023]   [Feb]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH v2 3/5] rust: types: implement `ForeignOwnable` for `Box<T>`
    Date

    Wedson Almeida Filho <wedsonaf@gmail.com> writes:

    > This allows us to hand ownership of Rust dynamically allocated
    > objects to the C side of the kernel.
    >
    > Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
    > Reviewed-by: Gary Guo <gary@garyguo.net>
    > Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
    > Reviewed-by: Alice Ferrazzi <alice.ferrazzi@miraclelinux.com>
    > ---

    Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>

    > v1 -> v2: Add `use alloc::boxed::Box`, which wasn't needed before
    >
    > rust/kernel/types.rs | 23 +++++++++++++++++++++++
    > 1 file changed, 23 insertions(+)
    >
    > diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
    > index 72710b7442a3..411655eca3e9 100644
    > --- a/rust/kernel/types.rs
    > +++ b/rust/kernel/types.rs
    > @@ -2,6 +2,7 @@
    >
    > //! Kernel types.
    >
    > +use alloc::boxed::Box;
    > use core::{
    > cell::UnsafeCell,
    > mem::MaybeUninit,
    > @@ -62,6 +63,28 @@ pub trait ForeignOwnable: Sized {
    > unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self;
    > }
    >
    > +impl<T: 'static> ForeignOwnable for Box<T> {
    > + type Borrowed<'a> = &'a T;
    > +
    > + fn into_foreign(self) -> *const core::ffi::c_void {
    > + Box::into_raw(self) as _
    > + }
    > +
    > + unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T {
    > + // SAFETY: The safety requirements for this function ensure that the object is still alive,
    > + // so it is safe to dereference the raw pointer.
    > + // The safety requirements of `from_foreign` also ensure that the object remains alive for
    > + // the lifetime of the returned value.
    > + unsafe { &*ptr.cast() }
    > + }
    > +
    > + unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
    > + // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous
    > + // call to `Self::into_foreign`.
    > + unsafe { Box::from_raw(ptr as _) }
    > + }
    > +}
    > +
    > /// Runs a cleanup function/closure when dropped.
    > ///
    > /// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running.

    \
     
     \ /
      Last update: 2023-03-27 00:04    [W:3.035 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site