rust: drm: restrict AlwaysRefCounted to Normal GEM Object context

Restrict AlwaysRefCounted for gem::Object and gem::shmem::Object to the
Normal context, since only Normal objects should be independently
reference-counted.

To avoid cascading through IntoGEMObject (which had AlwaysRefCounted as
a supertrait), remove AlwaysRefCounted from IntoGEMObject's supertraits
and instead add it as an explicit bound on lookup_handle(), which is the
only BaseObject method that returns an ARef.

Since Object::new() and shmem::Object::new() return ARef<Self>, move
them to Normal-only impl blocks. Similarly, simplify ObjectConfig and
shmem's parent_resv_obj field to the Normal context.

Remove the DeviceContext generic from DriverObject::new() and
Driver::Object, since GEM objects can only be constructed in the Normal
context. Simplify DriverAllocImpl accordingly.

Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com>
Link: https://patch.msgid.link/20260628145406.2107056-8-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 2 insertions, 9 deletions

diff --git a/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs
index c6d4d6f9bae3..1640a161754b 100644
--- a/drivers/gpu/drm/tyr/gem.rs
+++ b/drivers/gpu/drm/tyr/gem.rs
@@ -5,10 +5,7 @@
 //! DRM's GEM subsystem with shmem backing.
 
 use kernel::{
-    drm::{
-        gem,
-        DeviceContext, //
-    },
+    drm::gem,
     prelude::*, //
 };
 
@@ -33,11 +30,7 @@ impl gem::DriverObject for BoData {
     type Driver = TyrDrmDriver;
     type Args = BoCreateArgs;
 
-    fn new<Ctx: DeviceContext>(
-        _dev: &TyrDrmDevice<Ctx>,
-        _size: usize,
-        args: BoCreateArgs,
-    ) -> impl PinInit<Self, Error> {
+    fn new(_dev: &TyrDrmDevice, _size: usize, args: BoCreateArgs) -> impl PinInit<Self, Error> {
         try_pin_init!(Self { flags: args.flags })
     }
 }