1 files changed, 22 insertions, 10 deletions
diff --git a/crates/alloc_buddy/src/free_list.rs b/crates/alloc_buddy/src/free_list.rs
index 9b470fd..973ad2c 100644
--- a/crates/alloc_buddy/src/free_list.rs
+++ b/crates/alloc_buddy/src/free_list.rs
@@ -56,16 +56,7 @@ impl FreeList {
             unsafe {
                 // UNWRAP: In a valid circular doubly-linked list, the pointers are all non-null.
                 let node = (*self.0.as_ptr()).next.unwrap();
-                let prev = (*node.as_ptr()).prev.unwrap();
-                let next = (*node.as_ptr()).next.unwrap();
-
-                (*prev.as_ptr()).next = Some(next);
-                (*next.as_ptr()).prev = Some(prev);
-
-                (*node.as_ptr()).next = None;
-                (*node.as_ptr()).prev = None;
-                (*node.as_ptr()).magic = USED_NODE_MAGIC;
-                Some(node.cast())
+                Some(FreeListNode::unlink(node))
             }
         }
     }
@@ -161,4 +152,25 @@ impl FreeListNode {
         });
         ptr
     }
+
+    /// Unlinks the node from the circular doubly-linked list.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must be a non-sentinel node inside a valid free list.
+    #[requires(unsafe { (*node.as_ptr()).magic } == FREE_NODE_MAGIC)]
+    #[requires(unsafe { (*node.as_ptr()).self_addr } == node.as_ptr() as usize)]
+    pub unsafe fn unlink(node: NonNull<FreeListNode>) -> NonNull<u8> {
+        // UNWRAP: In a valid circular doubly-linked list, the pointers are all non-null.
+        let prev = (*node.as_ptr()).prev.unwrap();
+        let next = (*node.as_ptr()).next.unwrap();
+
+        (*prev.as_ptr()).next = Some(next);
+        (*next.as_ptr()).prev = Some(prev);
+
+        (*node.as_ptr()).next = None;
+        (*node.as_ptr()).prev = None;
+        (*node.as_ptr()).magic = USED_NODE_MAGIC;
+        node.cast()
+    }
 }