Add a deprecated dummy UnusedPhysFrame type to reduce breakage

Author: phil-opp

src/structures/paging/frame_alloc.rs

@@ -1,6 +1,6 @@
 //! Traits for abstracting away frame allocation and deallocation.
 
-use crate::structures::paging::{PageSize, PhysFrame};
+use crate::structures::paging::{PageSize, PhysFrame, Size4KiB};
 
 /// A trait for types that can allocate a frame of memory.
 ///
@@ -16,3 +16,22 @@ pub trait FrameDeallocator<S: PageSize> {
     /// Deallocate the given frame of memory.
     fn deallocate_frame(&mut self, frame: PhysFrame<S>);
 }
+
+/// Represents a physical frame that is not used for any mapping.
+#[deprecated(note = "This wrapper type was removed. Use `PhysFrame` instead.")]
+#[derive(Debug)]
+pub struct UnusedPhysFrame<S: PageSize = Size4KiB>(PhysFrame<S>);
+
+#[allow(deprecated)]
+impl<S: PageSize> UnusedPhysFrame<S> {
+    /// Creates a new UnusedPhysFrame from the given frame.
+    ///
+    /// ## Safety
+    ///
+    /// This method is unsafe because the caller must guarantee
+    /// that the given frame is unused.
+    #[allow(clippy::new_ret_no_self)]
+    pub unsafe fn new(frame: PhysFrame<S>) -> PhysFrame<S> {
+        frame
+    }
+}

src/structures/paging/mod.rs

@@ -3,6 +3,8 @@
 //! Page tables translate virtual memory “pages” to physical memory “frames”.
 
 pub use self::frame::PhysFrame;
+#[allow(deprecated)]
+pub use self::frame_alloc::UnusedPhysFrame;
 pub use self::frame_alloc::{FrameAllocator, FrameDeallocator};
 #[doc(no_inline)]
 pub use self::mapper::MappedPageTable;