| Message ID | 20230730012905.643822-4-boqun.feng@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix alignment issue and prepare for rust 1.71 | expand |
Boqun Feng <boqun.feng@gmail.com> writes: > From: Björn Roy Baron <bjorn3_gh@protonmail.com> > > 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 <bjorn3_gh@protonmail.com> > [boqun: add size adjustment for alignment requirement] > Signed-off-by: Boqun Feng <boqun.feng@gmail.com> > --- Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> > 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]
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]