On Thu, Oct 16, 2025 at 05:08:19PM -0400, Lyude Paul wrote:
> From: Asahi Lina <[email protected]>
>
> The DRM shmem helper includes common code useful for drivers which
> allocate GEM objects as anonymous shmem. Add a Rust abstraction for
> this. Drivers can choose the raw GEM implementation or the shmem layer,
> depending on their needs.
>
> Signed-off-by: Asahi Lina <[email protected]>
> Signed-off-by: Daniel Almeida <[email protected]>
> Signed-off-by: Lyude Paul <[email protected]>
> +impl<T: DriverObject> gem::IntoGEMObject for Object<T> {
> + fn as_raw(&self) -> *mut bindings::drm_gem_object {
> + // SAFETY: Our immutable reference is proof that this is are to
> dereference
> + unsafe { &raw mut (*self.obj.get()).base }
Typo.
Also, in principle, this should refer to a type invariant saying that
`obj` is a valid shmem object.
> + }
> +
> + unsafe fn from_raw<'a>(obj: *mut bindings::drm_gem_object) -> &'a
> Object<T> {
> + // SAFETY: The safety contract of from_gem_obj() guarantees that
> `obj` is contained within
> + // `Self`
> + unsafe {
> + let obj: *mut Opaque<_> =
> + container_of!(obj, bindings::drm_gem_shmem_object,
> base).cast();
Please use Opaque::cast_from() instead of the unrestricted cast()
operation.
There are several instances of this throughout the file.
Alice
