[PATCH v2] rust: drm: fix GEM object pointer safety docs

[Yilin Chen]

IntoGEMObject::from_raw() receives a pointer to struct drm_gem_object,
not a pointer to Self. The previous documentation used Self even though
the function argument is the embedded GEM object pointer.

However, the pointer must not be any arbitrary valid drm_gem_object. The
implementations recover Self with container_of(), so the GEM object must
be embedded in a valid Self instance. This patch documents that requirement
explicitly.

Assisted-by: Codex:GPT-5
Signed-off-by: Yilin Chen <1479826151@xxxxxx>
---
Changes in v2:
- Require the drm_gem_object to be embedded in a valid Self instance,
  rather than merely being any valid drm_gem_object.

 rust/kernel/drm/gem/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs
index c8b66d816..524ab0e39 100644
--- a/rust/kernel/drm/gem/mod.rs
+++ b/rust/kernel/drm/gem/mod.rs
@@ -118,7 +118,8 @@ pub trait IntoGEMObject: Sized + super::private::Sealed + AlwaysRefCounted {
     ///
     /// # Safety
     ///
-    /// - `self_ptr` must be a valid pointer to `Self`.
+    /// - `self_ptr` must be a valid pointer to the `struct drm_gem_object` embedded in a
+    ///   valid instance of `Self`.
     /// - The caller promises that holding the immutable reference returned by this function does
     ///   not violate rust's data aliasing rules and remains valid throughout the lifetime of `'a`.
     unsafe fn from_raw<'a>(self_ptr: *mut bindings::drm_gem_object) -> &'a Self;
-- 
2.25.1