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00280272a0
Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:
error: the item `bindings` is imported redundantly
--> rust/kernel/print.rs:38:9
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38 | use crate::bindings;
| ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude
Most cases are `use crate::bindings`, plus a few other items like `Box`.
Thus clean them up.
Note that, in the `bindings` case, the message "defined by prelude"
above means the extern prelude, i.e. the `--extern` flags we pass.
Link: https://github.com/rust-lang/rust/pull/117772 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
56 lines
1.9 KiB
Rust
56 lines
1.9 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Extensions to [`Box`] for fallible allocations.
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use super::{AllocError, Flags};
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use alloc::boxed::Box;
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use core::mem::MaybeUninit;
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/// Extensions to [`Box`].
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pub trait BoxExt<T>: Sized {
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/// Allocates a new box.
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///
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/// The allocation may fail, in which case an error is returned.
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fn new(x: T, flags: Flags) -> Result<Self, AllocError>;
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/// Allocates a new uninitialised box.
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///
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/// The allocation may fail, in which case an error is returned.
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fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError>;
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}
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impl<T> BoxExt<T> for Box<T> {
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fn new(x: T, flags: Flags) -> Result<Self, AllocError> {
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let b = <Self as BoxExt<_>>::new_uninit(flags)?;
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Ok(Box::write(b, x))
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}
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#[cfg(any(test, testlib))]
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fn new_uninit(_flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
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Ok(Box::new_uninit())
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}
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#[cfg(not(any(test, testlib)))]
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fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
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let ptr = if core::mem::size_of::<MaybeUninit<T>>() == 0 {
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core::ptr::NonNull::<_>::dangling().as_ptr()
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} else {
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let layout = core::alloc::Layout::new::<MaybeUninit<T>>();
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// SAFETY: Memory is being allocated (first arg is null). The only other source of
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// safety issues is sleeping on atomic context, which is addressed by klint. Lastly,
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// the type is not a SZT (checked above).
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let ptr =
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unsafe { super::allocator::krealloc_aligned(core::ptr::null_mut(), layout, flags) };
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if ptr.is_null() {
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return Err(AllocError);
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}
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ptr.cast::<MaybeUninit<T>>()
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};
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// SAFETY: For non-zero-sized types, we allocate above using the global allocator. For
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// zero-sized types, we use `NonNull::dangling`.
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Ok(unsafe { Box::from_raw(ptr) })
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}
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}
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