[PATCH v7 17/26] rust: alloc: remove `VecExt` extension

Danilo Krummrich posted 26 patches 2 months ago
There is a newer version of this series
[PATCH v7 17/26] rust: alloc: remove `VecExt` extension
Posted by Danilo Krummrich 2 months ago
Now that all existing `Vec` users were moved to the kernel `Vec` type,
remove the `VecExt` extension.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/alloc.rs         |   1 -
 rust/kernel/alloc/vec_ext.rs | 185 -----------------------------------
 rust/kernel/prelude.rs       |   5 +-
 3 files changed, 1 insertion(+), 190 deletions(-)
 delete mode 100644 rust/kernel/alloc/vec_ext.rs

diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
index e8fbae2adadb..aabdf80e4f7b 100644
--- a/rust/kernel/alloc.rs
+++ b/rust/kernel/alloc.rs
@@ -6,7 +6,6 @@
 pub mod allocator;
 pub mod kbox;
 pub mod kvec;
-pub mod vec_ext;
 
 #[cfg(any(test, testlib))]
 pub mod allocator_test;
diff --git a/rust/kernel/alloc/vec_ext.rs b/rust/kernel/alloc/vec_ext.rs
deleted file mode 100644
index 1297a4be32e8..000000000000
--- a/rust/kernel/alloc/vec_ext.rs
+++ /dev/null
@@ -1,185 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-//! Extensions to [`Vec`] for fallible allocations.
-
-use super::{AllocError, Flags};
-use alloc::vec::Vec;
-
-/// Extensions to [`Vec`].
-pub trait VecExt<T>: Sized {
-    /// Creates a new [`Vec`] instance with at least the given capacity.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let v = Vec::<u32>::with_capacity(20, GFP_KERNEL)?;
-    ///
-    /// assert!(v.capacity() >= 20);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError>;
-
-    /// Appends an element to the back of the [`Vec`] instance.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1]);
-    ///
-    /// v.push(2, GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 2]);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError>;
-
-    /// Pushes clones of the elements of slice into the [`Vec`] instance.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    ///
-    /// v.extend_from_slice(&[20, 30, 40], GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 20, 30, 40]);
-    ///
-    /// v.extend_from_slice(&[50, 60], GFP_KERNEL)?;
-    /// assert_eq!(&v, &[1, 20, 30, 40, 50, 60]);
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
-    where
-        T: Clone;
-
-    /// Ensures that the capacity exceeds the length by at least `additional` elements.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let mut v = Vec::new();
-    /// v.push(1, GFP_KERNEL)?;
-    ///
-    /// v.reserve(10, GFP_KERNEL)?;
-    /// let cap = v.capacity();
-    /// assert!(cap >= 10);
-    ///
-    /// v.reserve(10, GFP_KERNEL)?;
-    /// let new_cap = v.capacity();
-    /// assert_eq!(new_cap, cap);
-    ///
-    /// # Ok::<(), Error>(())
-    /// ```
-    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError>;
-}
-
-impl<T> VecExt<T> for Vec<T> {
-    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError> {
-        let mut v = Vec::new();
-        <Self as VecExt<_>>::reserve(&mut v, capacity, flags)?;
-        Ok(v)
-    }
-
-    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError> {
-        <Self as VecExt<_>>::reserve(self, 1, flags)?;
-        let s = self.spare_capacity_mut();
-        s[0].write(v);
-
-        // SAFETY: We just initialised the first spare entry, so it is safe to increase the length
-        // by 1. We also know that the new length is <= capacity because of the previous call to
-        // `reserve` above.
-        unsafe { self.set_len(self.len() + 1) };
-        Ok(())
-    }
-
-    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
-    where
-        T: Clone,
-    {
-        <Self as VecExt<_>>::reserve(self, other.len(), flags)?;
-        for (slot, item) in core::iter::zip(self.spare_capacity_mut(), other) {
-            slot.write(item.clone());
-        }
-
-        // SAFETY: We just initialised the `other.len()` spare entries, so it is safe to increase
-        // the length by the same amount. We also know that the new length is <= capacity because
-        // of the previous call to `reserve` above.
-        unsafe { self.set_len(self.len() + other.len()) };
-        Ok(())
-    }
-
-    #[cfg(any(test, testlib))]
-    fn reserve(&mut self, additional: usize, _flags: Flags) -> Result<(), AllocError> {
-        Vec::reserve(self, additional);
-        Ok(())
-    }
-
-    #[cfg(not(any(test, testlib)))]
-    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError> {
-        let len = self.len();
-        let cap = self.capacity();
-
-        if cap - len >= additional {
-            return Ok(());
-        }
-
-        if core::mem::size_of::<T>() == 0 {
-            // The capacity is already `usize::MAX` for SZTs, we can't go higher.
-            return Err(AllocError);
-        }
-
-        // We know cap is <= `isize::MAX` because `Layout::array` fails if the resulting byte size
-        // is greater than `isize::MAX`. So the multiplication by two won't overflow.
-        let new_cap = core::cmp::max(cap * 2, len.checked_add(additional).ok_or(AllocError)?);
-        let layout = core::alloc::Layout::array::<T>(new_cap).map_err(|_| AllocError)?;
-
-        let (old_ptr, len, cap) = destructure(self);
-
-        // We need to make sure that `ptr` is either NULL or comes from a previous call to
-        // `krealloc_aligned`. A `Vec<T>`'s `ptr` value is not guaranteed to be NULL and might be
-        // dangling after being created with `Vec::new`. Instead, we can rely on `Vec<T>`'s capacity
-        // to be zero if no memory has been allocated yet.
-        let ptr = if cap == 0 {
-            core::ptr::null_mut()
-        } else {
-            old_ptr
-        };
-
-        // SAFETY: `ptr` is valid because it's either NULL or comes from a previous call to
-        // `krealloc_aligned`. We also verified that the type is not a ZST.
-        let new_ptr = unsafe { super::allocator::krealloc_aligned(ptr.cast(), layout, flags) };
-        if new_ptr.is_null() {
-            // SAFETY: We are just rebuilding the existing `Vec` with no changes.
-            unsafe { rebuild(self, old_ptr, len, cap) };
-            Err(AllocError)
-        } else {
-            // SAFETY: `ptr` has been reallocated with the layout for `new_cap` elements. New cap
-            // is greater than `cap`, so it continues to be >= `len`.
-            unsafe { rebuild(self, new_ptr.cast::<T>(), len, new_cap) };
-            Ok(())
-        }
-    }
-}
-
-#[cfg(not(any(test, testlib)))]
-fn destructure<T>(v: &mut Vec<T>) -> (*mut T, usize, usize) {
-    let mut tmp = Vec::new();
-    core::mem::swap(&mut tmp, v);
-    let mut tmp = core::mem::ManuallyDrop::new(tmp);
-    let len = tmp.len();
-    let cap = tmp.capacity();
-    (tmp.as_mut_ptr(), len, cap)
-}
-
-/// Rebuilds a `Vec` from a pointer, length, and capacity.
-///
-/// # Safety
-///
-/// The same as [`Vec::from_raw_parts`].
-#[cfg(not(any(test, testlib)))]
-unsafe fn rebuild<T>(v: &mut Vec<T>, ptr: *mut T, len: usize, cap: usize) {
-    // SAFETY: The safety requirements from this function satisfy those of `from_raw_parts`.
-    let mut tmp = unsafe { Vec::from_raw_parts(ptr, len, cap) };
-    core::mem::swap(&mut tmp, v);
-}
diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
index 80223cdaa485..07daccf6ca8e 100644
--- a/rust/kernel/prelude.rs
+++ b/rust/kernel/prelude.rs
@@ -14,10 +14,7 @@
 #[doc(no_inline)]
 pub use core::pin::Pin;
 
-pub use crate::alloc::{flags::*, vec_ext::VecExt, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
-
-#[doc(no_inline)]
-pub use alloc::vec::Vec;
+pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
 
 #[doc(no_inline)]
 pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable};
-- 
2.46.0
Re: [PATCH v7 17/26] rust: alloc: remove `VecExt` extension
Posted by Gary Guo 1 month, 2 weeks ago
On Thu, 12 Sep 2024 00:52:53 +0200
Danilo Krummrich <dakr@kernel.org> wrote:

> Now that all existing `Vec` users were moved to the kernel `Vec` type,
> remove the `VecExt` extension.
> 
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Reviewed-by: Benno Lossin <benno.lossin@proton.me>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Reviewed-by: Gary Guo <gary@garyguo.net>

> ---
>  rust/kernel/alloc.rs         |   1 -
>  rust/kernel/alloc/vec_ext.rs | 185 -----------------------------------
>  rust/kernel/prelude.rs       |   5 +-
>  3 files changed, 1 insertion(+), 190 deletions(-)
>  delete mode 100644 rust/kernel/alloc/vec_ext.rs
> 
> diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
> index e8fbae2adadb..aabdf80e4f7b 100644
> --- a/rust/kernel/alloc.rs
> +++ b/rust/kernel/alloc.rs
> @@ -6,7 +6,6 @@
>  pub mod allocator;
>  pub mod kbox;
>  pub mod kvec;
> -pub mod vec_ext;
>  
>  #[cfg(any(test, testlib))]
>  pub mod allocator_test;
> diff --git a/rust/kernel/alloc/vec_ext.rs b/rust/kernel/alloc/vec_ext.rs
> deleted file mode 100644
> index 1297a4be32e8..000000000000
> --- a/rust/kernel/alloc/vec_ext.rs
> +++ /dev/null
> @@ -1,185 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -
> -//! Extensions to [`Vec`] for fallible allocations.
> -
> -use super::{AllocError, Flags};
> -use alloc::vec::Vec;
> -
> -/// Extensions to [`Vec`].
> -pub trait VecExt<T>: Sized {
> -    /// Creates a new [`Vec`] instance with at least the given capacity.
> -    ///
> -    /// # Examples
> -    ///
> -    /// ```
> -    /// let v = Vec::<u32>::with_capacity(20, GFP_KERNEL)?;
> -    ///
> -    /// assert!(v.capacity() >= 20);
> -    /// # Ok::<(), Error>(())
> -    /// ```
> -    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError>;
> -
> -    /// Appends an element to the back of the [`Vec`] instance.
> -    ///
> -    /// # Examples
> -    ///
> -    /// ```
> -    /// let mut v = Vec::new();
> -    /// v.push(1, GFP_KERNEL)?;
> -    /// assert_eq!(&v, &[1]);
> -    ///
> -    /// v.push(2, GFP_KERNEL)?;
> -    /// assert_eq!(&v, &[1, 2]);
> -    /// # Ok::<(), Error>(())
> -    /// ```
> -    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError>;
> -
> -    /// Pushes clones of the elements of slice into the [`Vec`] instance.
> -    ///
> -    /// # Examples
> -    ///
> -    /// ```
> -    /// let mut v = Vec::new();
> -    /// v.push(1, GFP_KERNEL)?;
> -    ///
> -    /// v.extend_from_slice(&[20, 30, 40], GFP_KERNEL)?;
> -    /// assert_eq!(&v, &[1, 20, 30, 40]);
> -    ///
> -    /// v.extend_from_slice(&[50, 60], GFP_KERNEL)?;
> -    /// assert_eq!(&v, &[1, 20, 30, 40, 50, 60]);
> -    /// # Ok::<(), Error>(())
> -    /// ```
> -    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
> -    where
> -        T: Clone;
> -
> -    /// Ensures that the capacity exceeds the length by at least `additional` elements.
> -    ///
> -    /// # Examples
> -    ///
> -    /// ```
> -    /// let mut v = Vec::new();
> -    /// v.push(1, GFP_KERNEL)?;
> -    ///
> -    /// v.reserve(10, GFP_KERNEL)?;
> -    /// let cap = v.capacity();
> -    /// assert!(cap >= 10);
> -    ///
> -    /// v.reserve(10, GFP_KERNEL)?;
> -    /// let new_cap = v.capacity();
> -    /// assert_eq!(new_cap, cap);
> -    ///
> -    /// # Ok::<(), Error>(())
> -    /// ```
> -    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError>;
> -}
> -
> -impl<T> VecExt<T> for Vec<T> {
> -    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError> {
> -        let mut v = Vec::new();
> -        <Self as VecExt<_>>::reserve(&mut v, capacity, flags)?;
> -        Ok(v)
> -    }
> -
> -    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError> {
> -        <Self as VecExt<_>>::reserve(self, 1, flags)?;
> -        let s = self.spare_capacity_mut();
> -        s[0].write(v);
> -
> -        // SAFETY: We just initialised the first spare entry, so it is safe to increase the length
> -        // by 1. We also know that the new length is <= capacity because of the previous call to
> -        // `reserve` above.
> -        unsafe { self.set_len(self.len() + 1) };
> -        Ok(())
> -    }
> -
> -    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
> -    where
> -        T: Clone,
> -    {
> -        <Self as VecExt<_>>::reserve(self, other.len(), flags)?;
> -        for (slot, item) in core::iter::zip(self.spare_capacity_mut(), other) {
> -            slot.write(item.clone());
> -        }
> -
> -        // SAFETY: We just initialised the `other.len()` spare entries, so it is safe to increase
> -        // the length by the same amount. We also know that the new length is <= capacity because
> -        // of the previous call to `reserve` above.
> -        unsafe { self.set_len(self.len() + other.len()) };
> -        Ok(())
> -    }
> -
> -    #[cfg(any(test, testlib))]
> -    fn reserve(&mut self, additional: usize, _flags: Flags) -> Result<(), AllocError> {
> -        Vec::reserve(self, additional);
> -        Ok(())
> -    }
> -
> -    #[cfg(not(any(test, testlib)))]
> -    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError> {
> -        let len = self.len();
> -        let cap = self.capacity();
> -
> -        if cap - len >= additional {
> -            return Ok(());
> -        }
> -
> -        if core::mem::size_of::<T>() == 0 {
> -            // The capacity is already `usize::MAX` for SZTs, we can't go higher.
> -            return Err(AllocError);
> -        }
> -
> -        // We know cap is <= `isize::MAX` because `Layout::array` fails if the resulting byte size
> -        // is greater than `isize::MAX`. So the multiplication by two won't overflow.
> -        let new_cap = core::cmp::max(cap * 2, len.checked_add(additional).ok_or(AllocError)?);
> -        let layout = core::alloc::Layout::array::<T>(new_cap).map_err(|_| AllocError)?;
> -
> -        let (old_ptr, len, cap) = destructure(self);
> -
> -        // We need to make sure that `ptr` is either NULL or comes from a previous call to
> -        // `krealloc_aligned`. A `Vec<T>`'s `ptr` value is not guaranteed to be NULL and might be
> -        // dangling after being created with `Vec::new`. Instead, we can rely on `Vec<T>`'s capacity
> -        // to be zero if no memory has been allocated yet.
> -        let ptr = if cap == 0 {
> -            core::ptr::null_mut()
> -        } else {
> -            old_ptr
> -        };
> -
> -        // SAFETY: `ptr` is valid because it's either NULL or comes from a previous call to
> -        // `krealloc_aligned`. We also verified that the type is not a ZST.
> -        let new_ptr = unsafe { super::allocator::krealloc_aligned(ptr.cast(), layout, flags) };
> -        if new_ptr.is_null() {
> -            // SAFETY: We are just rebuilding the existing `Vec` with no changes.
> -            unsafe { rebuild(self, old_ptr, len, cap) };
> -            Err(AllocError)
> -        } else {
> -            // SAFETY: `ptr` has been reallocated with the layout for `new_cap` elements. New cap
> -            // is greater than `cap`, so it continues to be >= `len`.
> -            unsafe { rebuild(self, new_ptr.cast::<T>(), len, new_cap) };
> -            Ok(())
> -        }
> -    }
> -}
> -
> -#[cfg(not(any(test, testlib)))]
> -fn destructure<T>(v: &mut Vec<T>) -> (*mut T, usize, usize) {
> -    let mut tmp = Vec::new();
> -    core::mem::swap(&mut tmp, v);
> -    let mut tmp = core::mem::ManuallyDrop::new(tmp);
> -    let len = tmp.len();
> -    let cap = tmp.capacity();
> -    (tmp.as_mut_ptr(), len, cap)
> -}
> -
> -/// Rebuilds a `Vec` from a pointer, length, and capacity.
> -///
> -/// # Safety
> -///
> -/// The same as [`Vec::from_raw_parts`].
> -#[cfg(not(any(test, testlib)))]
> -unsafe fn rebuild<T>(v: &mut Vec<T>, ptr: *mut T, len: usize, cap: usize) {
> -    // SAFETY: The safety requirements from this function satisfy those of `from_raw_parts`.
> -    let mut tmp = unsafe { Vec::from_raw_parts(ptr, len, cap) };
> -    core::mem::swap(&mut tmp, v);
> -}
> diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
> index 80223cdaa485..07daccf6ca8e 100644
> --- a/rust/kernel/prelude.rs
> +++ b/rust/kernel/prelude.rs
> @@ -14,10 +14,7 @@
>  #[doc(no_inline)]
>  pub use core::pin::Pin;
>  
> -pub use crate::alloc::{flags::*, vec_ext::VecExt, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
> -
> -#[doc(no_inline)]
> -pub use alloc::vec::Vec;
> +pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec};
>  
>  #[doc(no_inline)]
>  pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable};