diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index b4199945db37..48ffdd7400ca 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -26,6 +26,41 @@ ptr::NonNull, // }; +/// A macro for implementing [`AlwaysRefCounted`] for any GEM object type. +/// +/// Since all GEM objects use the same refcounting scheme. +#[macro_export] +macro_rules! impl_aref_for_gem_obj { + ( + impl $( <$( $tparam_id:ident ),+> )? for $type:ty + $( + where + $( $bind_param:path : $bind_trait:path ),+ + )? + ) => { + // SAFETY: All GEM objects are refcounted. + unsafe impl $( <$( $tparam_id ),+> )? $crate::types::AlwaysRefCounted for $type + where + Self: IntoGEMObject, + $( $( $bind_param : $bind_trait ),+ )? + { + fn inc_ref(&self) { + // SAFETY: The existence of a shared reference guarantees that the refcount is + // non-zero. + unsafe { bindings::drm_gem_object_get(self.as_raw()) }; + } + + unsafe fn dec_ref(obj: core::ptr::NonNull) { + // SAFETY: `obj` is a valid pointer to an `Object`. + let obj = unsafe { obj.as_ref() }.as_raw(); + + // SAFETY: The safety requirements guarantee that the refcount is non-zero. + unsafe { bindings::drm_gem_object_put(obj) }; + } + } + }; +} + /// A type alias for retrieving a [`Driver`]s [`DriverFile`] implementation from its /// [`DriverObject`] implementation. /// @@ -263,21 +298,7 @@ extern "C" fn free_callback(obj: *mut bindings::drm_gem_object) { } } -// SAFETY: Instances of `Object` are always reference-counted. -unsafe impl crate::sync::aref::AlwaysRefCounted for Object { - fn inc_ref(&self) { - // SAFETY: The existence of a shared reference guarantees that the refcount is non-zero. - unsafe { bindings::drm_gem_object_get(self.as_raw()) }; - } - - unsafe fn dec_ref(obj: NonNull) { - // SAFETY: `obj` is a valid pointer to an `Object`. - let obj = unsafe { obj.as_ref() }; - - // SAFETY: The safety requirements guarantee that the refcount is non-zero. - unsafe { bindings::drm_gem_object_put(obj.as_raw()) } - } -} +impl_aref_for_gem_obj!(impl for Object where T: DriverObject); impl super::private::Sealed for Object {}