[PATCH v2 02/12] rust: drm: gem: Add raw_dma_resv() function

[Lyude Paul]

For retrieving a pointer to the struct dma_resv for a given GEM object. We
also introduce it in a new trait, BaseObjectPrivate, which we automatically
implement for all gem objects and don't expose to users outside of the
crate.

Signed-off-by: Lyude Paul <lyude at redhat.com>
---
 rust/kernel/drm/gem/mod.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index 992e098d0a3e2..1165417b22df6 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -186,6 +186,17 @@ fn create_mmap_offset(&self) -> Result<u64> {
 
 impl<T: IntoGEMObject> BaseObject for T {}
 
+/// Crate-private base operations shared by all GEM object classes.
+pub(crate) trait BaseObjectPrivate: IntoGEMObject {
+    /// Return a pointer to this object's dma_resv.
+    fn raw_dma_resv(&self) -> *mut bindings::dma_resv {
+        // SAFETY: `as_gem_obj()` always returns a valid pointer to the base DRM gem object
+        unsafe { (*self.as_raw()).resv }
+    }
+}
+
+impl<T: IntoGEMObject> BaseObjectPrivate for T {}
+
 /// A base GEM object.
 ///
 /// Invariants
-- 
2.49.0