[PATCH v9 4/7] rust: gem: Introduce DriverObject::Args

[Lyude Paul <lyude@redhat.com>]

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>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Janne Grunau <j@jananu.net>

---
V3:
* s/BaseDriverObject/DriverObject/
V4:
* Fix leftover reference to BaseObjectDriver in rustdoc for
  DriverObject::Args
V6:
* Fix build errors in Tyr

Signed-off-by: Lyude Paul <lyude@redhat.com>
---
 drivers/gpu/drm/nova/gem.rs |  5 +++--
 drivers/gpu/drm/tyr/gem.rs  |  3 ++-
 rust/kernel/drm/gem/mod.rs  | 13 ++++++++++---
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/nova/gem.rs b/drivers/gpu/drm/nova/gem.rs
index 6ccfa5da57617..e073e174e2578 100644
--- a/drivers/gpu/drm/nova/gem.rs
+++ b/drivers/gpu/drm/nova/gem.rs
@@ -19,8 +19,9 @@ 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
         }
         let aligned_size = page::page_align(size).ok_or(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/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs
index 1273bf89dbd5d..bb5e7871efa94 100644
--- a/drivers/gpu/drm/tyr/gem.rs
+++ b/drivers/gpu/drm/tyr/gem.rs
@@ -11,8 +11,9 @@ pub(crate) struct TyrObject {}
 
 impl gem::DriverObject for TyrObject {
     type Driver = TyrDriver;
+    type Args = ();
 
-    fn new(_dev: &TyrDevice, _size: usize) -> impl PinInit<Self, Error> {
+    fn new(_dev: &TyrDevice, _size: usize, _args: ()) -> impl PinInit<Self, Error> {
         try_pin_init!(TyrObject {})
     }
 }
diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index bcec62155c02d..68bf33969a7d4 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -62,8 +62,15 @@ 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 {
@@ -242,11 +249,11 @@ 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),
             }),
             GFP_KERNEL,
         )?;
-- 
2.53.0