[RFC v3 26/33] rust: drm/kms: Add RawPlane::framebuffer()

[Lyude Paul]

Returns the Framebuffer currently assigned in an atomic plane state.

Signed-off-by: Lyude Paul <lyude at redhat.com>
---
 rust/kernel/drm/kms/framebuffer.rs |  1 -
 rust/kernel/drm/kms/plane.rs       | 18 +++++++++++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/drm/kms/framebuffer.rs b/rust/kernel/drm/kms/framebuffer.rs
index 5a60b580fe0bf..99f366e8813e2 100644
--- a/rust/kernel/drm/kms/framebuffer.rs
+++ b/rust/kernel/drm/kms/framebuffer.rs
@@ -66,7 +66,6 @@ impl<T: KmsDriver> Framebuffer<T> {
     /// The caller guarantews that `ptr` points to a initialized `struct drm_framebuffer` for at
     /// least the entire lifetime of `'a`.
     #[inline]
-    #[allow(dead_code)]
     pub(super) unsafe fn from_raw<'a>(ptr: *const bindings::drm_framebuffer) -> &'a Self {
         // SAFETY: Our data layout is identical to drm_framebuffer
         unsafe { &*ptr.cast() }
diff --git a/rust/kernel/drm/kms/plane.rs b/rust/kernel/drm/kms/plane.rs
index 63b453b7307fd..1d50632ae473f 100644
--- a/rust/kernel/drm/kms/plane.rs
+++ b/rust/kernel/drm/kms/plane.rs
@@ -5,7 +5,7 @@
 //! C header: [`include/drm/drm_plane.h`](srctree/include/drm/drm_plane.h)
 
 use super::{
-    atomic::*, crtc::*, KmsDriver, ModeObject, ModeObjectVtable, StaticModeObject,
+    atomic::*, crtc::*, framebuffer::*, KmsDriver, ModeObject, ModeObjectVtable, StaticModeObject,
     UnregisteredKmsDevice,
 };
 use crate::{
@@ -646,6 +646,22 @@ fn atomic_helper_check<S, D>(
             )
         })
     }
+
+    /// Return the framebuffer currently set for this plane state
+    #[inline]
+    fn framebuffer<D>(&self) -> Option<&Framebuffer<D>>
+    where
+        Self::Plane: ModeObject<Driver = D>,
+        D: KmsDriver,
+    {
+        // SAFETY: The layout of Framebuffer<T> is identical to `fb`
+        unsafe {
+            self.as_raw()
+                .fb
+                .as_ref()
+                .map(|fb| Framebuffer::from_raw(fb))
+        }
+    }
 }
 impl<T: AsRawPlaneState + ?Sized> RawPlaneState for T {}
 
-- 
2.48.1