From: Björn Roy Baron <[email protected]>
While there are default impls for these methods, using the respective C
api's is faster. Currently neither the existing nor these new
GlobalAlloc method implementations are actually called. Instead the
__rust_* function defined below the GlobalAlloc impl are used. With
rustc 1.71 these functions will be gone and all allocation calls will go
through the GlobalAlloc implementation.
Link: https://github.com/Rust-for-Linux/linux/issues/68
Signed-off-by: Björn Roy Baron <[email protected]>
[boqun: add size adjustment for alignment requirement]
Signed-off-by: Boqun Feng <[email protected]>
---
rust/kernel/allocator.rs | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
index 1aec688cf0e0..6f1f50465ab3 100644
--- a/rust/kernel/allocator.rs
+++ b/rust/kernel/allocator.rs
@@ -51,6 +51,33 @@ unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
bindings::kfree(ptr as *const core::ffi::c_void);
}
}
+
+ unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+ // SAFETY:
+ // - `new_size`, when rounded up to the nearest multiple of `layout.align()`, will not
+ // overflow `isize` by the function safety requirement.
+ // - `layout.align()` is a proper alignment (i.e. not zero and must be a power of two).
+ let layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
+
+ // SAFETY:
+ // - `ptr` is either null or a pointer allocated by this allocator by the function safety
+ // requirement.
+ // - the size of `layout` is not zero because `new_size` is not zero by the function safety
+ // requirement.
+ unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
+ }
+
+ unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+ // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+ // requirement.
+ unsafe {
+ krealloc_aligned(
+ ptr::null_mut(),
+ layout,
+ bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+ )
+ }
+ }
}
#[global_allocator]
--
2.41.0
Boqun Feng <[email protected]> writes:
> From: Björn Roy Baron <[email protected]>
>
> While there are default impls for these methods, using the respective C
> api's is faster. Currently neither the existing nor these new
> GlobalAlloc method implementations are actually called. Instead the
> __rust_* function defined below the GlobalAlloc impl are used. With
> rustc 1.71 these functions will be gone and all allocation calls will go
> through the GlobalAlloc implementation.
>
> Link: https://github.com/Rust-for-Linux/linux/issues/68
> Signed-off-by: Björn Roy Baron <[email protected]>
> [boqun: add size adjustment for alignment requirement]
> Signed-off-by: Boqun Feng <[email protected]>
> ---
Reviewed-by: Andreas Hindborg <[email protected]>
> rust/kernel/allocator.rs | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
> index 1aec688cf0e0..6f1f50465ab3 100644
> --- a/rust/kernel/allocator.rs
> +++ b/rust/kernel/allocator.rs
> @@ -51,6 +51,33 @@ unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
> bindings::kfree(ptr as *const core::ffi::c_void);
> }
> }
> +
> + unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
> + // SAFETY:
> + // - `new_size`, when rounded up to the nearest multiple of `layout.align()`, will not
> + // overflow `isize` by the function safety requirement.
> + // - `layout.align()` is a proper alignment (i.e. not zero and must be a power of two).
> + let layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
> +
> + // SAFETY:
> + // - `ptr` is either null or a pointer allocated by this allocator by the function safety
> + // requirement.
> + // - the size of `layout` is not zero because `new_size` is not zero by the function safety
> + // requirement.
> + unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
> + }
> +
> + unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
> + // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
> + // requirement.
> + unsafe {
> + krealloc_aligned(
> + ptr::null_mut(),
> + layout,
> + bindings::GFP_KERNEL | bindings::__GFP_ZERO,
> + )
> + }
> + }
> }
>
> #[global_allocator]