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-rw-r--r--rust/kernel/alloc/box_ext.rs89
1 files changed, 0 insertions, 89 deletions
diff --git a/rust/kernel/alloc/box_ext.rs b/rust/kernel/alloc/box_ext.rs
deleted file mode 100644
index 7009ad78d4e0..000000000000
--- a/rust/kernel/alloc/box_ext.rs
+++ /dev/null
@@ -1,89 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! Extensions to [`Box`] for fallible allocations.
-
-use super::{AllocError, Flags};
-use alloc::boxed::Box;
-use core::{mem::MaybeUninit, ptr, result::Result};
-
-/// Extensions to [`Box`].
-pub trait BoxExt<T>: Sized {
- /// Allocates a new box.
- ///
- /// The allocation may fail, in which case an error is returned.
- fn new(x: T, flags: Flags) -> Result<Self, AllocError>;
-
- /// Allocates a new uninitialised box.
- ///
- /// The allocation may fail, in which case an error is returned.
- fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError>;
-
- /// Drops the contents, but keeps the allocation.
- ///
- /// # Examples
- ///
- /// ```
- /// use kernel::alloc::{flags, box_ext::BoxExt};
- /// let value = Box::new([0; 32], flags::GFP_KERNEL)?;
- /// assert_eq!(*value, [0; 32]);
- /// let mut value = Box::drop_contents(value);
- /// // Now we can re-use `value`:
- /// value.write([1; 32]);
- /// // SAFETY: We just wrote to it.
- /// let value = unsafe { value.assume_init() };
- /// assert_eq!(*value, [1; 32]);
- /// # Ok::<(), Error>(())
- /// ```
- fn drop_contents(this: Self) -> Box<MaybeUninit<T>>;
-}
-
-impl<T> BoxExt<T> for Box<T> {
- fn new(x: T, flags: Flags) -> Result<Self, AllocError> {
- let mut b = <Self as BoxExt<_>>::new_uninit(flags)?;
- b.write(x);
- // SAFETY: We just wrote to it.
- Ok(unsafe { b.assume_init() })
- }
-
- #[cfg(any(test, testlib))]
- fn new_uninit(_flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
- Ok(Box::new_uninit())
- }
-
- #[cfg(not(any(test, testlib)))]
- fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
- let ptr = if core::mem::size_of::<MaybeUninit<T>>() == 0 {
- core::ptr::NonNull::<_>::dangling().as_ptr()
- } else {
- let layout = core::alloc::Layout::new::<MaybeUninit<T>>();
-
- // SAFETY: Memory is being allocated (first arg is null). The only other source of
- // safety issues is sleeping on atomic context, which is addressed by klint. Lastly,
- // the type is not a SZT (checked above).
- let ptr =
- unsafe { super::allocator::krealloc_aligned(core::ptr::null_mut(), layout, flags) };
- if ptr.is_null() {
- return Err(AllocError);
- }
-
- ptr.cast::<MaybeUninit<T>>()
- };
-
- // SAFETY: For non-zero-sized types, we allocate above using the global allocator. For
- // zero-sized types, we use `NonNull::dangling`.
- Ok(unsafe { Box::from_raw(ptr) })
- }
-
- fn drop_contents(this: Self) -> Box<MaybeUninit<T>> {
- let ptr = Box::into_raw(this);
- // SAFETY: `ptr` is valid, because it came from `Box::into_raw`.
- unsafe { ptr::drop_in_place(ptr) };
-
- // CAST: `MaybeUninit<T>` is a transparent wrapper of `T`.
- let ptr = ptr.cast::<MaybeUninit<T>>();
-
- // SAFETY: `ptr` is valid for writes, because it came from `Box::into_raw` and it is valid for
- // reads, since the pointer came from `Box::into_raw` and the type is `MaybeUninit<T>`.
- unsafe { Box::from_raw(ptr) }
- }
-}