[PATCH v5 4/8] rust: gem: Introduce DriverObject::Args

Lyude Paul
2025-10-23T21:26:30Z

This is an associated type that may be used in order to specify a data-type
to pass to gem objects when construction them, allowing for drivers to more
easily initialize their private-data for gem objects.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>

---
V3:
* s/BaseDriverObject/DriverObject/
V4:
* Fix leftover reference to BaseObjectDriver in rustdoc for
DriverObject::Args

drivers/gpu/drm/nova/gem.rs | 5 +++--
rust/kernel/drm/gem/mod.rs | 13 ++++++++++---
2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/nova/gem.rs b/drivers/gpu/drm/nova/gem.rs
index 2760ba4f3450b..173077eeb2def 100644
--- a/drivers/gpu/drm/nova/gem.rs
+++ b/drivers/gpu/drm/nova/gem.rs
@@ -18,8 +18,9 @@ pub(crate) struct NovaObject {}

impl gem::DriverObject for NovaObject {
type Driver = NovaDriver;
+ type Args = ();

- fn new(_dev: &NovaDevice, _size: usize) -> impl PinInit<Self, Error> {
+ fn new(_dev: &NovaDevice, _size: usize, _args: Self::Args) -> impl PinInit<Self, Error> {
try_pin_init!(NovaObject {})
}
}
@@ -33,7 +34,7 @@ pub(crate) fn new(dev: &NovaDevice, size: usize) -> Result<ARef<gem::Object<Self
return Err(EINVAL);
}

- gem::Object::new(dev, aligned_size)
+ gem::Object::new(dev, aligned_size, ())
}

/// Look up a GEM object handle for a `File` and return an `ObjectRef` for it.
diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index 67813cfb0db42..d448c65fe5e13 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -65,8 +65,15 @@ pub trait DriverObject: Sync + Send + Sized {
/// Parent `Driver` for this object.
type Driver: drm::Driver;

+ /// The data type to use for passing arguments to [`DriverObject::new`].
+ type Args;
+
/// Create a new driver data object for a GEM object of a given size.
- fn new(dev: &drm::Device<Self::Driver>, size: usize) -> impl PinInit<Self, Error>;
+ fn new(
+ dev: &drm::Device<Self::Driver>,
+ size: usize,
+ args: Self::Args,
+ ) -> impl PinInit<Self, Error>;

/// Open a new handle to an existing object, associated with a File.
fn open(_obj: &<Self::Driver as drm::Driver>::Object, _file: &DriverFile<Self>) -> Result {
@@ -247,11 +254,11 @@ impl<T: DriverObject> Object<T> {
};

/// Create a new GEM object.
- pub fn new(dev: &drm::Device<T::Driver>, size: usize) -> Result<ARef<Self>> {
+ pub fn new(dev: &drm::Device<T::Driver>, size: usize, args: T::Args) -> Result<ARef<Self>> {
let obj: Pin<KBox<Self>> = KBox::pin_init(
try_pin_init!(Self {
obj: Opaque::new(bindings::drm_gem_object::default()),
- data <- T::new(dev, size),
+ data <- T::new(dev, size, args),
// INVARIANT: The drm subsystem guarantees that the `struct drm_device` will live
// as long as the GEM object lives.
dev: dev.into(),
--
2.51.0