commit 567cdff53e71de56ae67eaf4309db38778b7bcd3 upstream.
In order to provide `// SAFETY` comments for every `unsafe impl`, we would need to repeat them, which is not very useful and would be harder to read.
We could perhaps allow the lint (ideally within a small module), but we can take the chance to avoid the repetition of the `impl`s themselves too by using a small local macro, like in other places where we have had to do this sort of thing.
Thus add the straightforward `impl_{from,as}bytes!` macros and use them to implement `FromBytes`.
This, in turn, will allow us in the next patch to place a `// SAFETY` comment that defers to the actual invocation of the macro.
Reviewed-by: Alice Ryhl aliceryhl@google.com Reviewed-by: Trevor Gross tmgross@umich.edu Tested-by: Gary Guo gary@garyguo.net Reviewed-by: Gary Guo gary@garyguo.net Link: https://lore.kernel.org/r/20240904204347.168520-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda ojeda@kernel.org --- rust/kernel/types.rs | 68 +++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 33 deletions(-)
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs index 9e7ca066355c..70e173f15d87 100644 --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -481,21 +481,22 @@ pub enum Either<L, R> { /// All bit-patterns must be valid for this type. This type must not have interior mutability. pub unsafe trait FromBytes {}
-// SAFETY: All bit patterns are acceptable values of the types below. -unsafe impl FromBytes for u8 {} -unsafe impl FromBytes for u16 {} -unsafe impl FromBytes for u32 {} -unsafe impl FromBytes for u64 {} -unsafe impl FromBytes for usize {} -unsafe impl FromBytes for i8 {} -unsafe impl FromBytes for i16 {} -unsafe impl FromBytes for i32 {} -unsafe impl FromBytes for i64 {} -unsafe impl FromBytes for isize {} -// SAFETY: If all bit patterns are acceptable for individual values in an array, then all bit -// patterns are also acceptable for arrays of that type. -unsafe impl<T: FromBytes> FromBytes for [T] {} -unsafe impl<T: FromBytes, const N: usize> FromBytes for [T; N] {} +macro_rules! impl_frombytes { + ($($({$($generics:tt)*})? $t:ty, )*) => { + $(unsafe impl$($($generics)*)? FromBytes for $t {})* + }; +} + +impl_frombytes! { + // SAFETY: All bit patterns are acceptable values of the types below. + u8, u16, u32, u64, usize, + i8, i16, i32, i64, isize, + + // SAFETY: If all bit patterns are acceptable for individual values in an array, then all bit + // patterns are also acceptable for arrays of that type. + {<T: FromBytes>} [T], + {<T: FromBytes, const N: usize>} [T; N], +}
/// Types that can be viewed as an immutable slice of initialized bytes. /// @@ -514,21 +515,22 @@ unsafe impl<T: FromBytes> FromBytes for [T] {} /// mutability. pub unsafe trait AsBytes {}
-// SAFETY: Instances of the following types have no uninitialized portions. -unsafe impl AsBytes for u8 {} -unsafe impl AsBytes for u16 {} -unsafe impl AsBytes for u32 {} -unsafe impl AsBytes for u64 {} -unsafe impl AsBytes for usize {} -unsafe impl AsBytes for i8 {} -unsafe impl AsBytes for i16 {} -unsafe impl AsBytes for i32 {} -unsafe impl AsBytes for i64 {} -unsafe impl AsBytes for isize {} -unsafe impl AsBytes for bool {} -unsafe impl AsBytes for char {} -unsafe impl AsBytes for str {} -// SAFETY: If individual values in an array have no uninitialized portions, then the array itself -// does not have any uninitialized portions either. -unsafe impl<T: AsBytes> AsBytes for [T] {} -unsafe impl<T: AsBytes, const N: usize> AsBytes for [T; N] {} +macro_rules! impl_asbytes { + ($($({$($generics:tt)*})? $t:ty, )*) => { + $(unsafe impl$($($generics)*)? AsBytes for $t {})* + }; +} + +impl_asbytes! { + // SAFETY: Instances of the following types have no uninitialized portions. + u8, u16, u32, u64, usize, + i8, i16, i32, i64, isize, + bool, + char, + str, + + // SAFETY: If individual values in an array have no uninitialized portions, then the array + // itself does not have any uninitialized portions either. + {<T: AsBytes>} [T], + {<T: AsBytes, const N: usize>} [T; N], +}