In the future we're going to be introducing more GEM object types in rust
then just gem::Object<T>. Since all types of GEM objects have refcounting,
let's introduce a macro that we can use in the gem crate in order to copy
this boilerplate implementation for each type: impl_aref_for_gem_obj!().
Signed-off-by: Lyude Paul <ly...@redhat.com>
---
rust/kernel/drm/gem/mod.rs | 53 +++++++++++++++++++++++++++-----------
1 file changed, 38 insertions(+), 15 deletions(-)
diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index af92f2d46d8d8..317edd455cc1c 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -14,6 +14,43 @@
};
use core::{ops::Deref, ptr::NonNull};
+/// A macro for implementing [`AlwaysRefCounted`] for any GEM object type.
+///
+/// Since all GEM objects use the same refcounting scheme.
+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
+ $( $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<Self>) {
+ // SAFETY: `obj` is a valid pointer to an `Object<T>`.
+ 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()) };
+ }
+ }
+ };
+}
+
+pub(crate) use impl_aref_for_gem_obj;
+
/// A type alias for retrieving a [`Driver`]s [`DriverFile`] implementation
from its
/// [`DriverObject`] implementation.
///
@@ -252,21 +289,7 @@ extern "C" fn free_callback(obj: *mut
bindings::drm_gem_object) {
}
}
-// SAFETY: Instances of `Object<T>` are always reference-counted.
-unsafe impl<T: DriverObject> crate::types::AlwaysRefCounted for Object<T> {
- 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<Self>) {
- // SAFETY: `obj` is a valid pointer to an `Object<T>`.
- 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<T> for Object<T> where T: DriverObject);
impl<T: DriverObject> super::private::Sealed for Object<T> {}
--
2.51.0
