From 47d8101924b58e03bfd065c972172e6b69331397 Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Tue, 10 Jun 2025 10:31:56 +0000 Subject: rust: vec: impl Default for Vec with any allocator The implementation of Default is restricted to only work with kmalloc vectors for no good reason. This means I have to use mem::replace(&mut my_vec, KVVec::new()) in Rust Binder instead of `mem::take(&mut my_vec)`. Thus, expand the impl of Default to work with any allocator including kvmalloc. Signed-off-by: Alice Ryhl Reviewed-by: Benno Lossin Link: https://lore.kernel.org/r/20250610-vec-default-v1-1-7bb2c97d75a0@google.com Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kvec.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'rust/kernel/alloc') diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 1a0dd852a468..606616fc0e59 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -851,7 +851,7 @@ where } } -impl Default for KVec { +impl Default for Vec { #[inline] fn default() -> Self { Self::new() -- cgit v1.2.3 From c09a8ac1cd560c8f944611045841fed99790116b Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Mon, 16 Jun 2025 12:34:05 +0900 Subject: rust: alloc: implement `Borrow` and `BorrowMut` for `Vec` Implement `Borrow<[T]>` and `BorrowMut<[T]>` for `Vec`. This allows `Vec` to be used in generic APIs asking for types implementing those traits. `[T; N]` and `&mut [T]` also implement those traits allowing users to use either owned, borrowed and heap-owned values. The implementation leverages `as_slice` and `as_mut_slice`. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Signed-off-by: Alexandre Courbot Link: https://lore.kernel.org/r/20250616-borrow_impls-v4-1-36f9beb3fe6a@nvidia.com Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kvec.rs | 53 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) (limited to 'rust/kernel/alloc') diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 606616fc0e59..cb543a61a33c 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -8,6 +8,7 @@ use super::{ AllocError, Allocator, Box, Flags, }; use core::{ + borrow::{Borrow, BorrowMut}, fmt, marker::PhantomData, mem::{ManuallyDrop, MaybeUninit}, @@ -890,6 +891,58 @@ where } } +/// # Examples +/// +/// ``` +/// # use core::borrow::Borrow; +/// struct Foo>(B); +/// +/// // Owned array. +/// let owned_array = Foo([1, 2, 3]); +/// +/// // Owned vector. +/// let owned_vec = Foo(KVec::from_elem(0, 3, GFP_KERNEL)?); +/// +/// let arr = [1, 2, 3]; +/// // Borrowed slice from `arr`. +/// let borrowed_slice = Foo(&arr[..]); +/// # Ok::<(), Error>(()) +/// ``` +impl Borrow<[T]> for Vec +where + A: Allocator, +{ + fn borrow(&self) -> &[T] { + self.as_slice() + } +} + +/// # Examples +/// +/// ``` +/// # use core::borrow::BorrowMut; +/// struct Foo>(B); +/// +/// // Owned array. +/// let owned_array = Foo([1, 2, 3]); +/// +/// // Owned vector. +/// let owned_vec = Foo(KVec::from_elem(0, 3, GFP_KERNEL)?); +/// +/// let mut arr = [1, 2, 3]; +/// // Borrowed slice from `arr`. +/// let borrowed_slice = Foo(&mut arr[..]); +/// # Ok::<(), Error>(()) +/// ``` +impl BorrowMut<[T]> for Vec +where + A: Allocator, +{ + fn borrow_mut(&mut self) -> &mut [T] { + self.as_mut_slice() + } +} + impl Eq for Vec where A: Allocator {} impl, A> Index for Vec -- cgit v1.2.3 From f86c0036c7de5fc379115809c653dfd57c453330 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Mon, 16 Jun 2025 12:34:07 +0900 Subject: rust: alloc: implement `Borrow` and `BorrowMut` for `KBox` Implement `Borrow` and `BorrowMut` for `KBox`. This allows `KBox` to be used in generic APIs asking for types implementing those traits. `T` and `&mut T` also implement those traits allowing users to use either owned, borrowed and heap-owned values. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Signed-off-by: Alexandre Courbot Link: https://lore.kernel.org/r/20250616-borrow_impls-v4-3-36f9beb3fe6a@nvidia.com Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kbox.rs | 57 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) (limited to 'rust/kernel/alloc') diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index c386ff771d50..ccf1df7da96c 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -6,6 +6,7 @@ use super::allocator::{KVmalloc, Kmalloc, Vmalloc}; use super::{AllocError, Allocator, Flags}; use core::alloc::Layout; +use core::borrow::{Borrow, BorrowMut}; use core::fmt; use core::marker::PhantomData; use core::mem::ManuallyDrop; @@ -499,6 +500,62 @@ where } } +/// # Examples +/// +/// ``` +/// # use core::borrow::Borrow; +/// # use kernel::alloc::KBox; +/// struct Foo>(B); +/// +/// // Owned instance. +/// let owned = Foo(1); +/// +/// // Owned instance using `KBox`. +/// let owned_kbox = Foo(KBox::new(1, GFP_KERNEL)?); +/// +/// let i = 1; +/// // Borrowed from `i`. +/// let borrowed = Foo(&i); +/// # Ok::<(), Error>(()) +/// ``` +impl Borrow for Box +where + T: ?Sized, + A: Allocator, +{ + fn borrow(&self) -> &T { + self.deref() + } +} + +/// # Examples +/// +/// ``` +/// # use core::borrow::BorrowMut; +/// # use kernel::alloc::KBox; +/// struct Foo>(B); +/// +/// // Owned instance. +/// let owned = Foo(1); +/// +/// // Owned instance using `KBox`. +/// let owned_kbox = Foo(KBox::new(1, GFP_KERNEL)?); +/// +/// let mut i = 1; +/// // Borrowed from `i`. +/// let borrowed = Foo(&mut i); +/// # Ok::<(), Error>(()) +/// ``` +impl BorrowMut for Box +where + T: ?Sized, + A: Allocator, +{ + fn borrow_mut(&mut self) -> &mut T { + self.deref_mut() + } +} + impl fmt::Display for Box where T: ?Sized + fmt::Display, -- cgit v1.2.3 From fcad9bbf9e1a7de6c53908954ba1b1a1ab11ef1e Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Sun, 15 Jun 2025 16:55:05 -0400 Subject: rust: enable `clippy::ptr_as_ptr` lint In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]: > Though `as` casts between raw pointers are not terrible, > `pointer::cast` is safer because it cannot accidentally change the > pointer's mutability, nor cast the pointer to other types like `usize`. There are a few classes of changes required: - Modules generated by bindgen are marked `#[allow(clippy::ptr_as_ptr)]`. - Inferred casts (` as _`) are replaced with `.cast()`. - Ascribed casts (` as *... T`) are replaced with `.cast::()`. - Multistep casts from references (` as *const _ as *const T`) are replaced with `core::ptr::from_ref(&x).cast()` with or without `::` according to the previous rules. The `core::ptr::from_ref` call is required because `(x as *const _).cast::()` results in inference failure. - Native literal C strings are replaced with `c_str!().as_char_ptr()`. - `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut T)`.cast();` since pointer to pointer can be confusing. Apply these changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1] Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng Signed-off-by: Tamir Duberstein Acked-by: Viresh Kumar Acked-by: Greg Kroah-Hartman Acked-by: Tejun Heo Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com [ Added `.cast()` for `opp`. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/allocator_test.rs | 2 +- rust/kernel/alloc/kvec.rs | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'rust/kernel/alloc') diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index d19c06ef0498..a3074480bd8d 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -82,7 +82,7 @@ unsafe impl Allocator for Cmalloc { // SAFETY: Returns either NULL or a pointer to a memory allocation that satisfies or // exceeds the given size and alignment requirements. - let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) } as *mut u8; + let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) }.cast::(); let dst = NonNull::new(dst).ok_or(AllocError)?; if flags.contains(__GFP_ZERO) { diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 1a0dd852a468..0477041cbc03 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -288,7 +288,7 @@ where // - `self.len` is smaller than `self.capacity` by the type invariant and hence, the // resulting pointer is guaranteed to be part of the same allocated object. // - `self.len` can not overflow `isize`. - let ptr = unsafe { self.as_mut_ptr().add(self.len) } as *mut MaybeUninit; + let ptr = unsafe { self.as_mut_ptr().add(self.len) }.cast::>(); // SAFETY: The memory between `self.len` and `self.capacity` is guaranteed to be allocated // and valid, but uninitialized. @@ -847,7 +847,7 @@ where // - `ptr` points to memory with at least a size of `size_of::() * len`, // - all elements within `b` are initialized values of `T`, // - `len` does not exceed `isize::MAX`. - unsafe { Vec::from_raw_parts(ptr as _, len, len) } + unsafe { Vec::from_raw_parts(ptr.cast(), len, len) } } } -- cgit v1.2.3 From 12717ebeffcf3e34063dbc1e1b7f34924150c7c9 Mon Sep 17 00:00:00 2001 From: Andreas Hindborg Date: Thu, 12 Jun 2025 15:09:43 +0200 Subject: rust: types: add FOREIGN_ALIGN to ForeignOwnable MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current implementation of `ForeignOwnable` is leaking the type of the opaque pointer to consumers of the API. This allows consumers of the opaque pointer to rely on the information that can be extracted from the pointer type. To prevent this, change the API to the version suggested by Maira Canal (link below): Remove `ForeignOwnable::PointedTo` in favor of a constant, which specifies the alignment of the pointers returned by `into_foreign`. With this change, `ArcInner` no longer needs `pub` visibility, so change it to private. Suggested-by: Alice Ryhl Suggested-by: Maíra Canal Link: https://lore.kernel.org/r/20240309235927.168915-3-mcanal@igalia.com Acked-by: Danilo Krummrich Reviewed-by: Benno Lossin Signed-off-by: Andreas Hindborg Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250612-pointed-to-v3-1-b009006d86a1@kernel.org Signed-off-by: Miguel Ojeda --- rust/kernel/alloc/kbox.rs | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) (limited to 'rust/kernel/alloc') diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index c386ff771d50..bffe72f44cb3 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -15,6 +15,7 @@ use core::pin::Pin; use core::ptr::NonNull; use core::result::Result; +use crate::ffi::c_void; use crate::init::InPlaceInit; use crate::types::ForeignOwnable; use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption}; @@ -398,70 +399,74 @@ where } } -// SAFETY: The `into_foreign` function returns a pointer that is well-aligned. +// SAFETY: The pointer returned by `into_foreign` comes from a well aligned +// pointer to `T`. unsafe impl ForeignOwnable for Box where A: Allocator, { - type PointedTo = T; + const FOREIGN_ALIGN: usize = core::mem::align_of::(); type Borrowed<'a> = &'a T; type BorrowedMut<'a> = &'a mut T; - fn into_foreign(self) -> *mut Self::PointedTo { - Box::into_raw(self) + fn into_foreign(self) -> *mut c_void { + Box::into_raw(self).cast() } - unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self { + unsafe fn from_foreign(ptr: *mut 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) } + unsafe { Box::from_raw(ptr.cast()) } } - unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> &'a T { + unsafe fn borrow<'a>(ptr: *mut c_void) -> &'a T { // SAFETY: The safety requirements of this method ensure that the object remains alive and // immutable for the duration of 'a. - unsafe { &*ptr } + unsafe { &*ptr.cast() } } - unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> &'a mut T { + unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> &'a mut T { + let ptr = ptr.cast(); // SAFETY: The safety requirements of this method ensure that the pointer is valid and that // nothing else will access the value for the duration of 'a. unsafe { &mut *ptr } } } -// SAFETY: The `into_foreign` function returns a pointer that is well-aligned. +// SAFETY: The pointer returned by `into_foreign` comes from a well aligned +// pointer to `T`. unsafe impl ForeignOwnable for Pin> where A: Allocator, { - type PointedTo = T; + const FOREIGN_ALIGN: usize = core::mem::align_of::(); type Borrowed<'a> = Pin<&'a T>; type BorrowedMut<'a> = Pin<&'a mut T>; - fn into_foreign(self) -> *mut Self::PointedTo { + fn into_foreign(self) -> *mut c_void { // SAFETY: We are still treating the box as pinned. - Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }) + Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }).cast() } - unsafe fn from_foreign(ptr: *mut Self::PointedTo) -> Self { + unsafe fn from_foreign(ptr: *mut c_void) -> Self { // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous // call to `Self::into_foreign`. - unsafe { Pin::new_unchecked(Box::from_raw(ptr)) } + unsafe { Pin::new_unchecked(Box::from_raw(ptr.cast())) } } - unsafe fn borrow<'a>(ptr: *mut Self::PointedTo) -> Pin<&'a T> { + unsafe fn borrow<'a>(ptr: *mut c_void) -> Pin<&'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. - let r = unsafe { &*ptr }; + let r = unsafe { &*ptr.cast() }; // SAFETY: This pointer originates from a `Pin>`. unsafe { Pin::new_unchecked(r) } } - unsafe fn borrow_mut<'a>(ptr: *mut Self::PointedTo) -> Pin<&'a mut T> { + unsafe fn borrow_mut<'a>(ptr: *mut c_void) -> Pin<&'a mut T> { + let ptr = ptr.cast(); // 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 -- cgit v1.2.3