[PATCH 09/13] rust: drm/gem/shmem: add resident_size() and madv() for debugfs

[Alvin Sun <alvin.sun@linux.dev>]

Expose resident size and madvise state of shmem GEM objects so drivers
can show per-BO memory usage and reclaimable size in debugfs.

Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 rust/kernel/drm/gem/shmem.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs
index 065bdd78d1ba6..ba25a4a832db6 100644
--- a/rust/kernel/drm/gem/shmem.rs
+++ b/rust/kernel/drm/gem/shmem.rs
@@ -196,6 +196,27 @@ extern "C" fn free_callback(obj: *mut bindings::drm_gem_object) {
         let _ = unsafe { KBox::from_raw(this) };
     }
 
+    /// Returns the resident size of this object.
+    #[inline]
+    pub fn resident_size(&self) -> usize {
+        // SAFETY: `self.as_raw_shmem()` is guaranteed to be a valid pointer to a
+        // drm_gem_shmem_object.
+        if unsafe { (*self.as_raw_shmem()).pages }.is_null() {
+            0
+        } else {
+            // SAFETY: `self.as_raw()` is guaranteed to be a valid pointer to a drm_gem_object.
+            unsafe { (*self.as_raw()).size }
+        }
+    }
+
+    /// Returns the state for madvise of this object.
+    #[inline]
+    pub fn madv(&self) -> i32 {
+        // SAFETY: `self.as_raw_shmem()` is guaranteed to be a valid pointer to a
+        // drm_gem_shmem_object.
+        unsafe { (*self.as_raw_shmem()).madv }
+    }
+
     /// Creates (if necessary) and returns an immutable reference to a scatter-gather table of DMA
     /// pages for this object.
     ///

-- 
2.43.0