feat: linked_list: allow to have multiple links in a same struct

kernel/src/objects/cap.rs

@@ -42,12 +42,14 @@ impl RawCap {
     }
 }
 
+pub const CAP_ENTRY_LINK_ID: usize = 1;
+
 pub struct CapEntry {
     pub cap:  RawCap,
-    pub link: Link<Self>,
+    pub link: Link<Self, CAP_ENTRY_LINK_ID>,
 }
 
-LinkHelperImpl!(CapEntry: link);
+LinkHelperImpl!(CapEntry { link } => CAP_ENTRY_LINK_ID);
 
 impl CapEntry {
     pub fn new(cap: RawCap) -> Self {

kernel/src/objects/tcb.rs

@@ -24,6 +24,8 @@ pub enum ThreadState {
     Idle,
 }
 
+pub const SCHED_QUEUE_LINK_ID: usize = 1;
+
 #[repr(C)]
 pub struct TcbObject {
     pub trapframe: TrapContext, // must be the first field
@@ -38,10 +40,11 @@ pub struct TcbObject {
     state:     ThreadState,
     time_tick: usize,
     tid:       usize,
-    pub link:  Link<Self>,
+
+    pub sched_queue: Link<Self, SCHED_QUEUE_LINK_ID>,
 }
 
-LinkHelperImpl!(TcbObject:link);
+LinkHelperImpl!(TcbObject { sched_queue } => SCHED_QUEUE_LINK_ID);
 
 const_assert_eq!(ObjectType::TCB.size(0), ObjectType::TCB.size(0x42));
 const_assert!(core::mem::size_of::<TcbObject>() <= ObjectType::TCB.size(0));
@@ -59,7 +62,7 @@ impl TcbObject {
             state:         ThreadState::Inactive,
             time_tick:     0,
             tid:           TID_ALLOCATOR.fetch_add(1, Ordering::SeqCst),
-            link:          Link::default(),
+            sched_queue:   Link::default(),
         }
     }
 

kernel/src/scheduler.rs

@@ -2,6 +2,7 @@ use crate::objects::*;
 use core::sync::atomic::AtomicPtr;
 use log::{error, trace};
 use spin::lazy::Lazy;
+use tcb::SCHED_QUEUE_LINK_ID;
 use utils::{container_of_mut, linked_list::Link};
 
 #[thread_local]
@@ -17,7 +18,7 @@ pub static SCHEDULER: Scheduler = Scheduler::new();
 // TODO: add a shared buffer to transfer TCB between cores
 
 pub struct Scheduler {
-    head: Link<TcbObject>,
+    head: Link<TcbObject, SCHED_QUEUE_LINK_ID>,
 }
 
 impl Scheduler {
@@ -27,7 +28,7 @@ impl Scheduler {
 
     pub fn init(&self) {
         unsafe {
-            let head = Some(AtomicPtr::new(container_of_mut!(&self.head, TcbObject, link)));
+            let head = Some(AtomicPtr::new(container_of_mut!(&self.head, TcbObject, sched_queue)));
             self.head.set_next(&head);
             self.head.set_prev(&head);
         }
@@ -48,7 +49,7 @@ impl Scheduler {
 
             // put to the end of the queue
             if next.timetick() == 0 || !next.schedulable() {
-                next.link.detach();
+                next.sched_queue.detach();
                 self.head.prepend(next);
             }
         }

lib/utils/src/linked_list.rs

@@ -13,35 +13,39 @@ macro_rules! as_mut_ptr {
 
 #[macro_export]
 macro_rules! LinkHelperImpl {
-    ($type:ty : $field:ident) => {
+    ($type:ty { $field:ident } => $id:expr) => {
-        impl LinkHelper for $type {
+        impl LinkHelper<$id> for $type {
             const LINK_OFFSET: usize = core::mem::offset_of!($type, $field) as usize;
         }
     };
 }
 
-pub trait LinkHelper: Sized {
+pub trait LinkHelper<const ID: usize>: Sized {
     const LINK_OFFSET: usize;
 
     /// # Safety
     /// LINK_OFFSET must be a valid field offset of Self
-    unsafe fn get_link(&self) -> &Link<Self> {
+    unsafe fn get_link(&self) -> &Link<Self, ID> {
-        &*(to_field_offset!(self, Link<Self>, Self::LINK_OFFSET))
+        &*(to_field_offset!(self, Link<Self, ID>, Self::LINK_OFFSET))
     }
 }
 
-pub struct Link<T: LinkHelper> {
+unsafe fn get_link<T: LinkHelper<ID>, const ID: usize>(node: &T) -> &Link<T, ID> {
+    <T as LinkHelper<ID>>::get_link(node)
+}
+
+pub struct Link<T: LinkHelper<ID>, const ID: usize> {
     pub prev: Option<AtomicPtr<T>>,
     pub next: Option<AtomicPtr<T>>,
 }
 
-impl<T: LinkHelper> Default for Link<T> {
+impl<T: LinkHelper<ID>, const ID: usize> Default for Link<T, ID> {
     fn default() -> Self {
         Self::new()
     }
 }
 
-impl<T: LinkHelper> Clone for Link<T> {
+impl<T: LinkHelper<ID>, const ID: usize> Clone for Link<T, ID> {
     fn clone(&self) -> Self {
         Self {
             prev: copy_ptr(&self.prev),
@@ -50,7 +54,7 @@ impl<T: LinkHelper> Clone for Link<T> {
     }
 }
 
-impl<T: LinkHelper> Link<T> {
+impl<T: LinkHelper<ID>, const ID: usize> Link<T, ID> {
     pub const fn new() -> Self {
         Self { prev: None, next: None }
     }
@@ -104,12 +108,12 @@ impl<T: LinkHelper> Link<T> {
     pub fn prepend(&self, new: &T) {
         unsafe {
             // setup new's link
-            new.get_link().set_prev(self.prev_raw());
+            get_link(new).set_prev(self.prev_raw());
-            new.get_link().set_next(&Some(AtomicPtr::new(as_mut_ptr!(self.object()))));
+            get_link(new).set_next(&Some(AtomicPtr::new(as_mut_ptr!(self.object()))));
 
             // setup prev's link
             if let Some(prev) = self.prev_raw() {
-                load_ptr(prev).get_link().set_next(&Some(AtomicPtr::new(as_mut_ptr!(new))));
+                get_link(load_ptr(prev)).set_next(&Some(AtomicPtr::new(as_mut_ptr!(new))));
             }
 
             // setup self's link
@@ -120,12 +124,12 @@ impl<T: LinkHelper> Link<T> {
     pub fn append(&self, new: &T) {
         unsafe {
             // setup new's link
-            new.get_link().set_prev(&Some(AtomicPtr::new(as_mut_ptr!(self.object()))));
+            get_link(new).set_prev(&Some(AtomicPtr::new(as_mut_ptr!(self.object()))));
-            new.get_link().set_next(self.next_raw());
+            get_link(new).set_next(self.next_raw());
 
             // setup next's link
             if let Some(next) = self.next_raw() {
-                load_ptr(next).get_link().set_prev(&Some(AtomicPtr::new(as_mut_ptr!(new))))
+                get_link(load_ptr(next)).set_prev(&Some(AtomicPtr::new(as_mut_ptr!(new))))
             }
 
             // setup self's link
@@ -137,12 +141,12 @@ impl<T: LinkHelper> Link<T> {
         unsafe {
             // setup prev's link
             if let Some(prev) = self.prev_raw() {
-                load_ptr(prev).get_link().set_next(self.next_raw())
+                get_link(load_ptr(prev)).set_next(self.next_raw())
             }
 
             // setup next's link
             if let Some(next) = self.next_raw() {
-                load_ptr(next).get_link().set_prev(self.prev_raw())
+                get_link(load_ptr(next)).set_prev(self.prev_raw())
             }
 
             // setup self's link
@@ -167,94 +171,191 @@ mod tests {
     use super::*;
 
     struct Node {
-        link:  Link<Node>,
+        link1: Link<Node, 1>,
+        link2: Link<Node, 2>,
         value: i32,
     }
 
-    LinkHelperImpl!(Node: link);
+    LinkHelperImpl!(Node { link1 } => 1);
+    LinkHelperImpl!(Node { link2 } => 2);
 
     #[test]
     fn test_linked_list() {
-        let node1 = Node {
+        let n1 = Node {
-            link:  Link::default(),
+            link1: Link::default(),
+            link2: Link::default(),
             value: 1,
         };
-        let node2 = Node {
+        let n2 = Node {
-            link:  Link::default(),
+            link1: Link::default(),
+            link2: Link::default(),
             value: 2,
         };
-        let node3 = Node {
+        let n3 = Node {
-            link:  Link::default(),
+            link1: Link::default(),
+            link2: Link::default(),
             value: 3,
         };
 
-        node1.link.append(&node2);
+        // link1: node1 <-> node2 <-> node3
-        node2.link.append(&node3);
+        n1.link1.append(&n2);
+        n2.link1.append(&n3);
 
+        // link2: node1 <-> node3 <-> node2
+        n1.link2.append(&n3);
+        n3.link2.append(&n2);
+
+        // link1: check object
         unsafe {
-            // check object
+            assert_eq!(as_mut_ptr!(n1.link1.object() => Node), as_mut_ptr!(&n1 => Node));
-            assert_eq!(as_mut_ptr!(node1.link.object() => Node), as_mut_ptr!(&node1 => Node));
+            assert_eq!(n1.link1.object().value, 1);
-            assert_eq!(node1.link.object().value, 1);
+            assert_eq!(as_mut_ptr!(n2.link1.object() => Node), as_mut_ptr!(&n2 => Node));
-            assert_eq!(as_mut_ptr!(node2.link.object() => Node), as_mut_ptr!(&node2 => Node));
+            assert_eq!(n2.link1.object().value, 2);
-            assert_eq!(node2.link.object().value, 2);
+            assert_eq!(as_mut_ptr!(n3.link1.object() => Node), as_mut_ptr!(&n3 => Node));
-            assert_eq!(as_mut_ptr!(node3.link.object() => Node), as_mut_ptr!(&node3 => Node));
+            assert_eq!(n3.link1.object().value, 3);
-            assert_eq!(node3.link.object().value, 3);
         }
 
+        // link2: check object
         unsafe {
-            // check get_link
+            assert_eq!(as_mut_ptr!(n1.link2.object() => Node), as_mut_ptr!(&n1 => Node));
-            assert_eq!(as_mut_ptr!(node1.get_link() => Link<Node>), as_mut_ptr!(&node1.link));
+            assert_eq!(n1.link2.object().value, 1);
-            assert_eq!(as_mut_ptr!(node2.get_link() => Link<Node>), as_mut_ptr!(&node2.link));
+            assert_eq!(as_mut_ptr!(n2.link2.object() => Node), as_mut_ptr!(&n2 => Node));
-            assert_eq!(as_mut_ptr!(node3.get_link() => Link<Node>), as_mut_ptr!(&node3.link));
+            assert_eq!(n2.link2.object().value, 2);
+            assert_eq!(as_mut_ptr!(n3.link2.object() => Node), as_mut_ptr!(&n3 => Node));
+            assert_eq!(n3.link2.object().value, 3);
         }
 
-        {
+        // link1: check get_link
-            // check next link
+        unsafe {
-            assert!(node1.link.next_raw().is_some());
+            assert_eq!(as_mut_ptr!(get_link::<_, 1>(&n1) => Link<Node, 1>), as_mut_ptr!(&n1.link1));
-            assert_eq!(
+            assert_eq!(as_mut_ptr!(get_link::<_, 1>(&n2) => Link<Node, 1>), as_mut_ptr!(&n2.link1));
-                node1.link.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+            assert_eq!(as_mut_ptr!(get_link::<_, 1>(&n3) => Link<Node, 1>), as_mut_ptr!(&n3.link1));
-                as_mut_ptr!(&node2)
-            );
-            assert!(node2.link.next_raw().is_some());
-            assert_eq!(
-                node2.link.next_raw().as_ref().unwrap().load(Ordering::Acquire),
-                as_mut_ptr!(&node3)
-            );
-            assert!(node3.link.next_raw().is_none());
         }
 
+        // link2: check get_link
+        unsafe {
+            assert_eq!(as_mut_ptr!(get_link::<_, 2>(&n1) => Link<Node, 2>), as_mut_ptr!(&n1.link2));
+            assert_eq!(as_mut_ptr!(get_link::<_, 2>(&n2) => Link<Node, 2>), as_mut_ptr!(&n2.link2));
+            assert_eq!(as_mut_ptr!(get_link::<_, 2>(&n3) => Link<Node, 2>), as_mut_ptr!(&n3.link2));
+        }
+
+        // link1: check next link
         {
-            // check prev link
+            // node1 -> node2
-            assert!(node1.link.prev_raw().is_none());
+            assert!(n1.link1.next_raw().is_some());
-            assert!(node2.link.prev_raw().is_some());
             assert_eq!(
-                node2.link.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                n1.link1.next_raw().as_ref().unwrap().load(Ordering::Acquire),
-                as_mut_ptr!(&node1)
+                as_mut_ptr!(&n2)
             );
-            assert!(node3.link.prev_raw().is_some());
+
+            // node2 -> node3
+            assert!(n2.link1.next_raw().is_some());
             assert_eq!(
-                node3.link.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                n2.link1.next_raw().as_ref().unwrap().load(Ordering::Acquire),
-                as_mut_ptr!(&node2)
+                as_mut_ptr!(&n3)
+            );
+
+            // node3 -> None
+            assert!(n3.link1.next_raw().is_none());
+        }
+
+        // link2: check next link
+        {
+            // node1 -> node3
+            assert!(n1.link2.next_raw().is_some());
+            assert_eq!(
+                n1.link2.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n3)
+            );
+
+            // node3 -> node2
+            assert!(n3.link2.next_raw().is_some());
+            assert_eq!(
+                n3.link2.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n2)
+            );
+
+            // node2 -> None
+            assert!(n2.link2.next_raw().is_none());
+        }
+
+        // link1: check prev link
+        {
+            // none <- node1
+            assert!(n1.link1.prev_raw().is_none());
+
+            // node1 <- node2
+            assert!(n2.link1.prev_raw().is_some());
+            assert_eq!(
+                n2.link1.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n1)
+            );
+
+            // node2 <- node3
+            assert!(n3.link1.prev_raw().is_some());
+            assert_eq!(
+                n3.link1.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n2)
             );
         }
 
+        // link2: check prev link
         {
-            // check detach
+            // none <- node1
-            node2.link.detach();
+            assert!(n1.link2.prev_raw().is_none());
 
-            assert!(node2.link.next_raw().is_none());
+            // node1 <- node3
-            assert!(node2.link.prev_raw().is_none());
+            assert!(n3.link2.prev_raw().is_some());
-
-            assert!(node1.link.next_raw().is_some());
             assert_eq!(
-                node1.link.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+                n3.link2.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
-                as_mut_ptr!(&node3)
+                as_mut_ptr!(&n1)
             );
 
-            assert!(node3.link.prev_raw().is_some());
+            // node3 <- node2
+            assert!(n2.link2.prev_raw().is_some());
             assert_eq!(
-                node3.link.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                n2.link2.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
-                as_mut_ptr!(&node1)
+                as_mut_ptr!(&n3)
+            );
+        }
+
+        // link1: check detach
+        {
+            n2.link1.detach();
+
+            assert!(n2.link1.next_raw().is_none());
+            assert!(n2.link1.prev_raw().is_none());
+
+            assert!(n1.link1.next_raw().is_some());
+            assert_eq!(
+                n1.link1.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n3)
+            );
+
+            assert!(n3.link1.prev_raw().is_some());
+            assert_eq!(
+                n3.link1.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n1)
+            );
+        }
+
+        // link2: check detach
+        {
+            n3.link2.detach();
+
+            assert!(n3.link2.next_raw().is_none());
+            assert!(n3.link2.prev_raw().is_none());
+
+            assert!(n1.link2.next_raw().is_some());
+            assert_eq!(
+                n1.link2.next_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n2)
+            );
+
+            assert!(n2.link2.prev_raw().is_some());
+            assert_eq!(
+                n2.link2.prev_raw().as_ref().unwrap().load(Ordering::Acquire),
+                as_mut_ptr!(&n1)
             );
         }
     }