On Wed, Jun 11, 2025 at 12:46 PM Andreas Hindborg <a.hindborg@xxxxxxxxxx> wrote: > > "Alice Ryhl" <aliceryhl@xxxxxxxxxx> writes: > > > On Thu, Jun 5, 2025 at 10:00 PM Andreas Hindborg <a.hindborg@xxxxxxxxxx> wrote: > >> > >> 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`. > >> > >> Suggested-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > >> Suggested-by: Maíra Canal <mcanal@xxxxxxxxxx> > >> Link: https://lore.kernel.org/r/20240309235927.168915-3-mcanal@xxxxxxxxxx > >> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxx> > > > > One nit below. With that and things other folks mentioned fixed, you may add: > > > > Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > > > >> diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs > >> index 22985b6f6982..025c619a2195 100644 > >> --- a/rust/kernel/types.rs > >> +++ b/rust/kernel/types.rs > >> @@ -21,15 +21,11 @@ > >> /// > >> /// # Safety > >> /// > >> -/// Implementers must ensure that [`into_foreign`] returns a pointer which meets the alignment > >> -/// requirements of [`PointedTo`]. > >> -/// > >> -/// [`into_foreign`]: Self::into_foreign > >> -/// [`PointedTo`]: Self::PointedTo > >> +/// Implementers must ensure that [`Self::into_foreign`] return pointers with alignment that is an > >> +/// integer multiple of [`Self::FOREIGN_ALIGN`]. > > > > We should require non-null: > > What is your rationale for this? The rationale is that the implementation of XArray assumes that the pointers are non-null. If we allow null pointers, we will need to fix the XArray. Alice
