Commit cc41670e authored by Wedson Almeida Filho's avatar Wedson Almeida Filho Committed by Miguel Ojeda
Browse files

rust: sync: update `Arc` and `UniqueArc` to take allocation flags 



We also remove the `try_` prefix to align with how `Box` and `Vec` are
providing methods now.

`init` is temporarily updated with uses of GFP_KERNEL. These will be
updated in a subsequent patch to take flags as well.

Reviewed-by: default avatarBenno Lossin <benno.lossin@proton.me>
Signed-off-by: default avatarWedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240328013603.206764-9-wedsonaf@gmail.com


Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent 5ab560ce

rust/kernel/init.rs

+2 −2
Original line number Diff line number Diff line
@@ -1189,7 +1189,7 @@ fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E> 
    where

        E: From<AllocError>,

    {

        let mut this = UniqueArc::try_new_uninit()?;

        let mut this = UniqueArc::new_uninit(GFP_KERNEL)?;

        let slot = this.as_mut_ptr();

        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,

        // slot is valid and will not be moved, because we pin it later.
@@ -1203,7 +1203,7 @@ fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E> 
    where

        E: From<AllocError>,

    {

        let mut this = UniqueArc::try_new_uninit()?;

        let mut this = UniqueArc::new_uninit(GFP_KERNEL)?;

        let slot = this.as_mut_ptr();

        // SAFETY: When init errors/panics, slot will get deallocated but not dropped,

        // slot is valid.

rust/kernel/sync/arc.rs

+14 −14
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
//! [`Arc`]: https://doc.rust-lang.org/std/sync/struct.Arc.html



use crate::{

    alloc::{box_ext::BoxExt, flags::*},

    alloc::{box_ext::BoxExt, Flags},

    bindings,

    error::{self, Error},

    init::{self, InPlaceInit, Init, PinInit},
@@ -58,7 +58,7 @@ 
/// }

///

/// // Create a refcounted instance of `Example`.

/// let obj = Arc::try_new(Example { a: 10, b: 20 })?;

/// let obj = Arc::new(Example { a: 10, b: 20 }, GFP_KERNEL)?;

///

/// // Get a new pointer to `obj` and increment the refcount.

/// let cloned = obj.clone();
@@ -97,7 +97,7 @@ 
///     }

/// }

///

/// let obj = Arc::try_new(Example { a: 10, b: 20 })?;

/// let obj = Arc::new(Example { a: 10, b: 20 }, GFP_KERNEL)?;

/// obj.use_reference();

/// obj.take_over();

/// # Ok::<(), Error>(())
@@ -120,7 +120,7 @@ 
/// impl MyTrait for Example {}

///

/// // `obj` has type `Arc<Example>`.

/// let obj: Arc<Example> = Arc::try_new(Example)?;

/// let obj: Arc<Example> = Arc::new(Example, GFP_KERNEL)?;

///

/// // `coerced` has type `Arc<dyn MyTrait>`.

/// let coerced: Arc<dyn MyTrait> = obj;
@@ -163,7 +163,7 @@ unsafe impl<T: ?Sized + Sync + Send> Sync for Arc<T> {} 


impl<T> Arc<T> {

    /// Constructs a new reference counted instance of `T`.

    pub fn try_new(contents: T) -> Result<Self, AllocError> {

    pub fn new(contents: T, flags: Flags) -> Result<Self, AllocError> {

        // INVARIANT: The refcount is initialised to a non-zero value.

        let value = ArcInner {

            // SAFETY: There are no safety requirements for this FFI call.
@@ -171,7 +171,7 @@ pub fn try_new(contents: T) -> Result<Self, AllocError> { 
            data: contents,

        };



        let inner = <Box<_> as BoxExt<_>>::new(value, GFP_KERNEL)?;

        let inner = <Box<_> as BoxExt<_>>::new(value, flags)?;



        // SAFETY: We just created `inner` with a reference count of 1, which is owned by the new

        // `Arc` object.
@@ -388,7 +388,7 @@ fn from(item: Pin<UniqueArc<T>>) -> Self { 
///     e.into()

/// }

///

/// let obj = Arc::try_new(Example)?;

/// let obj = Arc::new(Example, GFP_KERNEL)?;

/// let cloned = do_something(obj.as_arc_borrow());

///

/// // Assert that both `obj` and `cloned` point to the same underlying object.
@@ -412,7 +412,7 @@ fn from(item: Pin<UniqueArc<T>>) -> Self { 
///     }

/// }

///

/// let obj = Arc::try_new(Example { a: 10, b: 20 })?;

/// let obj = Arc::new(Example { a: 10, b: 20 }, GFP_KERNEL)?;

/// obj.as_arc_borrow().use_reference();

/// # Ok::<(), Error>(())

/// ```
@@ -500,7 +500,7 @@ fn deref(&self) -> &Self::Target { 
/// }

///

/// fn test() -> Result<Arc<Example>> {

///     let mut x = UniqueArc::try_new(Example { a: 10, b: 20 })?;

///     let mut x = UniqueArc::new(Example { a: 10, b: 20 }, GFP_KERNEL)?;

///     x.a += 1;

///     x.b += 1;

///     Ok(x.into())
@@ -523,7 +523,7 @@ fn deref(&self) -> &Self::Target { 
/// }

///

/// fn test() -> Result<Arc<Example>> {

///     let x = UniqueArc::try_new_uninit()?;

///     let x = UniqueArc::new_uninit(GFP_KERNEL)?;

///     Ok(x.write(Example { a: 10, b: 20 }).into())

/// }

///
@@ -543,7 +543,7 @@ fn deref(&self) -> &Self::Target { 
/// }

///

/// fn test() -> Result<Arc<Example>> {

///     let mut pinned = Pin::from(UniqueArc::try_new(Example { a: 10, b: 20 })?);

///     let mut pinned = Pin::from(UniqueArc::new(Example { a: 10, b: 20 }, GFP_KERNEL)?);

///     // We can modify `pinned` because it is `Unpin`.

///     pinned.as_mut().a += 1;

///     Ok(pinned.into())
@@ -557,15 +557,15 @@ pub struct UniqueArc<T: ?Sized> { 


impl<T> UniqueArc<T> {

    /// Tries to allocate a new [`UniqueArc`] instance.

    pub fn try_new(value: T) -> Result<Self, AllocError> {

    pub fn new(value: T, flags: Flags) -> Result<Self, AllocError> {

        Ok(Self {

            // INVARIANT: The newly-created object has a refcount of 1.

            inner: Arc::try_new(value)?,

            inner: Arc::new(value, flags)?,

        })

    }



    /// Tries to allocate a new [`UniqueArc`] instance whose contents are not initialised yet.

    pub fn try_new_uninit() -> Result<UniqueArc<MaybeUninit<T>>, AllocError> {

    pub fn new_uninit(_flags: Flags) -> Result<UniqueArc<MaybeUninit<T>>, AllocError> {

        // INVARIANT: The refcount is initialised to a non-zero value.

        let inner = Box::try_init::<AllocError>(try_init!(ArcInner {

            // SAFETY: There are no safety requirements for this FFI call.

samples/rust/rust_print.rs

+2 −2
Original line number Diff line number Diff line
@@ -18,8 +18,8 @@ 
fn arc_print() -> Result {

    use kernel::sync::*;



    let a = Arc::try_new(1)?;

    let b = UniqueArc::try_new("hello, world")?;

    let a = Arc::new(1, GFP_KERNEL)?;

    let b = UniqueArc::new("hello, world", GFP_KERNEL)?;



    // Prints the value of data in `a`.

    pr_info!("{}", a);