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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: mcduiiidmkhwpprjwgaeqjjenaqdmomf X-Rspamd-Queue-Id: B07F140022 X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1713445331-406008 X-HE-Meta: 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 VOumg7WL nGU55XV2xKg50vTpR6rUM6syKttQk1TeBpkCNj8ksUHXkaf43EpA8sBR1I3RJMlZ6brSH7i8Gft6mfM4Tngav/vj8ENHjQgdAQZcomwjXiwZXYEGYdIWs+SgqGrJWwt/0cHiVF31vGy0wg6p6aU7VMT3E303Xclrwhuj9jExNj3p/PbG7sT2s9OBDJrUZ0LnstAWeTHJljFJs+MojOlx5iD9mSWpUqes8S14ajfnk+9CkoiM/NK4ndVWoX8DzfG/eb+pmdvEoOUF3g4PNKW46GSv+tWOSDDhDsCE+/ENWIzO5eyLY0d6DEapUqtXaVHl65mWN X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 18.04.24 10:59, Alice Ryhl wrote: > diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs > index 8fad61268465..9c57c6c75553 100644 > --- a/rust/kernel/types.rs > +++ b/rust/kernel/types.rs > @@ -409,3 +409,67 @@ pub enum Either { > /// Constructs an instance of [`Either`] containing a value of type = `R`. > Right(R), > } > + > +/// Types for which any bit pattern is valid. > +/// > +/// Not all types are valid for all values. For example, a `bool` must b= e either zero or one, so > +/// reading arbitrary bytes into something that contains a `bool` is not= okay. > +/// > +/// It's okay for the type to have padding, as initializing those bytes = has no effect. > +/// > +/// # Safety > +/// > +/// All bit-patterns must be valid for this type. This type must not hav= e interior mutability. What is the reason for disallowing interior mutability here? I agree that it is necessary for `AsBytes`, but I don't think we need it here. For example it is fine to convert `u8` to `UnsafeCell`. Niches also should not be a problem, since eg `Option>>` already fails the "All bit-patterns must be valid for this type". --=20 Cheers, Benno > +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 {}