Replace the original XArray with RCU-based XArray

Cargo.lock

@@ -229,7 +229,7 @@ dependencies = [
  "time",
  "typeflags",
  "typeflags-util",
- "xarray 0.1.0",
+ "xarray",
  "xmas-elf 0.8.0",
 ]
 
@@ -1324,7 +1324,6 @@ dependencies = [
  "volatile 0.6.1",
  "x86",
  "x86_64",
- "xarray 0.1.0 (git+https://github.com/asterinas/xarray)",
 ]
 
 [[package]]
@@ -1984,14 +1983,6 @@ dependencies = [
  "ostd",
 ]
 
-[[package]]
-name = "xarray"
-version = "0.1.0"
-source = "git+https://github.com/asterinas/xarray#1dad5d9b74aac30193bd242a97077b4c54933830"
-dependencies = [
- "smallvec",
-]
-
 [[package]]
 name = "xmas-elf"
 version = "0.8.0"

ostd/Cargo.toml

@@ -37,7 +37,6 @@ spin = "0.9.4"
 smallvec = "1.13.2"
 unwinding = { version = "=0.2.5", default-features = false, features = ["fde-gnu-eh-frame-hdr", "hide-trace", "panic", "personality", "unwinder"] }
 volatile = "0.6.1"
-xarray = { git = "https://github.com/asterinas/xarray", version = "0.1.0" }
 
 [target.x86_64-unknown-none.dependencies]
 x86_64 = "0.14.13"

ostd/src/collections/mod.rs

@@ -1,6 +0,0 @@
-// SPDX-License-Identifier: MPL-2.0
-
-//! This module provides some advanced collections.
-
-// TODO: Remove the old xarray module.
-pub mod xarray;

ostd/src/collections/xarray.rs

@@ -1,6 +0,0 @@
-// SPDX-License-Identifier: MPL-2.0
-
-//! This module introduces the xarray crate and provides relevant support and interfaces for `XArray`.
-extern crate xarray as xarray_crate;
-
-pub use xarray_crate::{Cursor, CursorMut, XArray, XMark};

ostd/src/lib.rs

@@ -33,7 +33,6 @@ pub mod arch;
 pub mod arch;
 pub mod boot;
 pub mod bus;
-pub mod collections;
 pub mod console;
 pub mod cpu;
 mod error;

ostd/src/mm/frame/test.rs

@@ -486,8 +486,8 @@ mod untyped {
     }
 
     #[ktest]
-    fn xarray_item_entry() {
-        use xarray::ItemEntry;
+    fn frame_impls_non_null_ptr() {
+        use crate::sync::non_null::NonNullPtr;
 
         let init_val = 42;
         let frame = FrameAllocOptions::new()
@@ -497,13 +497,13 @@ mod untyped {
         let uframe: UFrame = frame.into();
 
         // Converts and retrieves the frame from raw pointer
-        let raw_ptr = ItemEntry::into_raw(uframe);
-        let frame_from_raw: Frame<MockUFrameMeta> = unsafe { ItemEntry::from_raw(raw_ptr) };
+        let raw_ptr = NonNullPtr::into_raw(uframe);
+        let frame_from_raw: Frame<MockUFrameMeta> = unsafe { NonNullPtr::from_raw(raw_ptr.cast()) };
         assert_eq!(frame_from_raw.start_paddr(), ptr);
         assert_eq!(frame_from_raw.meta().value, init_val);
 
         // References the frame from raw pointer
-        let frame_ref: FrameRef<MockUFrameMeta> = unsafe { Frame::raw_as_ref(raw_ptr) };
+        let frame_ref: FrameRef<MockUFrameMeta> = unsafe { Frame::raw_as_ref(raw_ptr.cast()) };
         assert_eq!(frame_ref.start_paddr(), ptr);
     }
 }

ostd/src/mm/frame/untyped.rs

@@ -7,12 +7,16 @@
 //! the declaration of untyped frames and segments, and the implementation of
 //! extra functionalities (such as [`VmIo`]) for them.
 
-use super::{meta::AnyFrameMeta, Frame, Segment};
+use super::{
+    meta::{AnyFrameMeta, MetaSlot},
+    Frame, Segment,
+};
 use crate::{
     mm::{
         io::{FallibleVmRead, FallibleVmWrite, VmIo, VmReader, VmWriter},
         paddr_to_vaddr, Infallible,
     },
+    sync::non_null::NonNullPtr,
     Error, Result,
 };
 
@@ -132,13 +136,13 @@ macro_rules! impl_untyped_for {
 impl_untyped_for!(Frame);
 impl_untyped_for!(Segment);
 
-// Here are implementations for `xarray`.
+// Here are implementations for `crate::sync::rcu`.
 
-use core::{marker::PhantomData, mem::ManuallyDrop, ops::Deref};
+use core::{marker::PhantomData, mem::ManuallyDrop, ops::Deref, ptr::NonNull};
 
 /// `FrameRef` is a struct that can work as `&'a Frame<m>`.
 ///
-/// This is solely useful for [`crate::collections::xarray`].
+/// This is useful for [`crate::sync::rcu`].
 pub struct FrameRef<'a, M: AnyUFrameMeta + ?Sized> {
     inner: ManuallyDrop<Frame<M>>,
     _marker: PhantomData<&'a Frame<M>>,
@@ -152,34 +156,42 @@ impl<M: AnyUFrameMeta + ?Sized> Deref for FrameRef<'_, M> {
     }
 }
 
-// SAFETY: `Frame` is essentially an `*const MetaSlot` that could be used as a `*const` pointer.
-// The pointer is also aligned to 4.
-unsafe impl<M: AnyUFrameMeta + ?Sized> xarray::ItemEntry for Frame<M> {
+// SAFETY: `Frame` is essentially an `*const MetaSlot` that could be used as a non-null
+// `*const` pointer.
+unsafe impl<M: AnyUFrameMeta + ?Sized> NonNullPtr for Frame<M> {
+    type Target = PhantomData<Self>;
+
     type Ref<'a>
         = FrameRef<'a, M>
     where
         Self: 'a;
 
-    fn into_raw(self) -> *const () {
-        let ptr = self.ptr;
+    const ALIGN_BITS: u32 = core::mem::align_of::<MetaSlot>().trailing_zeros();
+
+    fn into_raw(self) -> NonNull<Self::Target> {
+        let ptr = NonNull::new(self.ptr.cast_mut()).unwrap();
         let _ = ManuallyDrop::new(self);
-        ptr as *const ()
+        ptr.cast()
     }
 
-    unsafe fn from_raw(raw: *const ()) -> Self {
+    unsafe fn from_raw(raw: NonNull<Self::Target>) -> Self {
         Self {
-            ptr: raw as *const _,
+            ptr: raw.as_ptr().cast_const().cast(),
             _marker: PhantomData,
         }
     }
 
-    unsafe fn raw_as_ref<'a>(raw: *const ()) -> Self::Ref<'a> {
+    unsafe fn raw_as_ref<'a>(raw: NonNull<Self::Target>) -> Self::Ref<'a> {
         Self::Ref {
             inner: ManuallyDrop::new(Frame {
-                ptr: raw as *const _,
+                ptr: raw.as_ptr().cast_const().cast(),
                 _marker: PhantomData,
             }),
             _marker: PhantomData,
         }
     }
+
+    fn ref_as_raw(ptr_ref: Self::Ref<'_>) -> core::ptr::NonNull<Self::Target> {
+        NonNull::new(ptr_ref.inner.ptr.cast_mut()).unwrap().cast()
+    }
 }