[PATCH v2 3/4] rust: drm: gem: Add ObjectFile type alias

[Lyude Paul]

Just to reduce the clutter with the File<…> types in gem.rs.

Signed-off-by: Lyude Paul <lyude at redhat.com>
---
 rust/kernel/drm/gem/mod.rs | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index c17b36948bae3..2b81298d29765 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -17,6 +17,13 @@
 /// A type alias for the Object type in use by a [`drm::Driver`].
 pub type DriverObject<T> = <<T as BaseDriverObject>::Driver as drm::Driver>::Object;
 
+/// A type alias for retrieving a [`Driver`]s [`DriverFile`] implementation from its
+/// [`DriverObject`] implementation.
+///
+/// [`Driver`]: drm::Driver
+/// [`DriverFile`]: drm::file::DriverFile
+pub type ObjectFile<T> = drm::File<<<T as BaseDriverObject>::Driver as drm::Driver>::File>;
+
 /// GEM object functions, which must be implemented by drivers.
 pub trait BaseDriverObject: Sync + Send + Sized {
     /// Parent `Driver` for this object.
@@ -26,15 +33,12 @@ pub trait BaseDriverObject: Sync + Send + Sized {
     fn new(dev: &drm::Device<Self::Driver>, size: usize) -> impl PinInit<Self, Error>;
 
     /// Open a new handle to an existing object, associated with a File.
-    fn open(
-        _obj: &DriverObject<Self>,
-        _file: &drm::File<<Self::Driver as drm::Driver>::File>,
-    ) -> Result {
+    fn open(_obj: &DriverObject<Self>, _file: &ObjectFile<Self>) -> Result {
         Ok(())
     }
 
     /// Close a handle to an existing object, associated with a File.
-    fn close(_obj: &DriverObject<Self>, _file: &drm::File<<Self::Driver as drm::Driver>::File>) {}
+    fn close(_obj: &DriverObject<Self>, _file: &ObjectFile<Self>) {}
 }
 
 /// Trait that represents a GEM object subtype
@@ -78,7 +82,8 @@ extern "C" fn open_callback<T: BaseDriverObject>(
     raw_file: *mut bindings::drm_file,
 ) -> core::ffi::c_int {
     // SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.
-    let file = unsafe { drm::File::<<T::Driver as drm::Driver>::File>::as_ref(raw_file) };
+    let file = unsafe { ObjectFile::<T>::as_ref(raw_file) };
+
     // SAFETY: `open_callback` is specified in the AllocOps structure for `DriverObject<T>`,
     // ensuring that `raw_obj` is contained within a `DriverObject<T>`
     let obj = unsafe { DriverObject::<T>::as_ref(raw_obj) };
@@ -94,7 +99,7 @@ extern "C" fn close_callback<T: BaseDriverObject>(
     raw_file: *mut bindings::drm_file,
 ) {
     // SAFETY: `open_callback` is only ever called with a valid pointer to a `struct drm_file`.
-    let file = unsafe { drm::File::<<T::Driver as drm::Driver>::File>::as_ref(raw_file) };
+    let file = unsafe { ObjectFile::<T>::as_ref(raw_file) };
 
     // SAFETY: `close_callback` is specified in the AllocOps structure for `Object<T>`, ensuring
     // that `raw_obj` is indeed contained within a `Object<T>`.
@@ -125,7 +130,7 @@ fn size(&self) -> usize {
 
     /// Creates a new handle for the object associated with a given `File`
     /// (or returns an existing one).
-    fn create_handle(&self, file: &drm::File<<Self::Driver as drm::Driver>::File>) -> Result<u32>
+    fn create_handle(&self, file: &ObjectFile<Self>) -> Result<u32>
     where
         Self: BaseDriverObject,
     {
@@ -138,10 +143,7 @@ fn create_handle(&self, file: &drm::File<<Self::Driver as drm::Driver>::File>) -
     }
 
     /// Looks up an object by its handle for a given `File`.
-    fn lookup_handle(
-        file: &drm::File<<Self::Driver as drm::Driver>::File>,
-        handle: u32,
-    ) -> Result<ARef<Self>>
+    fn lookup_handle(file: &ObjectFile<Self>, handle: u32) -> Result<ARef<Self>>
     where
         Self: BaseDriverObject,
     {
-- 
2.49.0