vmo-paged: use internal owner ID

zircon-object/src/vm/vmo/mod.rs

@@ -60,12 +60,7 @@ pub trait VMObjectTrait: Sync + Send {
     fn decommit(&self, offset: usize, len: usize) -> ZxResult;
 
     /// Create a child VMO.
-    fn create_child(
-        &self,
-        offset: usize,
-        len: usize,
-        user_id: KoID,
-    ) -> ZxResult<Arc<dyn VMObjectTrait>>;
+    fn create_child(&self, offset: usize, len: usize) -> ZxResult<Arc<dyn VMObjectTrait>>;
 
     /// Append a mapping to the VMO's mapping list.
     fn append_mapping(&self, _mapping: Weak<VmMapping>) {}
@@ -143,7 +138,7 @@ impl VmObject {
         Arc::new(VmObject {
             resizable,
             _counter: CountHelper::new(),
-            trait_: VMObjectPaged::new(base.id, pages),
+            trait_: VMObjectPaged::new(pages),
             inner: Mutex::new(VmObjectInner::default()),
             base,
         })
@@ -169,7 +164,7 @@ impl VmObject {
         }
         let base = KObjectBase::with_signal(Signal::VMO_ZERO_CHILDREN);
         let size_page = pages(size);
-        let trait_ = VMObjectPaged::new(base.id, size_page);
+        let trait_ = VMObjectPaged::new(size_page);
         trait_.create_contiguous(size, align_log2)?;
         let vmo = Arc::new(VmObject {
             base,
@@ -190,7 +185,7 @@ impl VmObject {
     ) -> ZxResult<Arc<Self>> {
         let base = KObjectBase::with_signal(Signal::VMO_ZERO_CHILDREN);
         base.set_name(&self.base.name());
-        let trait_ = self.trait_.create_child(offset, len, base.id)?;
+        let trait_ = self.trait_.create_child(offset, len)?;
         let child = Arc::new(VmObject {
             base,
             resizable,

zircon-object/src/vm/vmo/paged.rs

@@ -70,8 +70,8 @@ type WeakRef = Weak<VMObjectPaged>;
 
 /// The mutable part of `VMObjectPaged`.
 struct VMObjectPagedInner {
-    /// Id of this vmo object
-    user_id: KoID,
+    /// Owner identifier.
+    owner: u64,
     type_: VMOType,
     /// Parent node.
     parent: Option<Arc<VMObjectPaged>>,
@@ -157,10 +157,10 @@ impl Drop for PageState {
 
 impl VMObjectPaged {
     /// Create a new VMO backing on physical memory allocated in pages.
-    pub fn new(id: KoID, pages: usize) -> Arc<Self> {
+    pub fn new(pages: usize) -> Arc<Self> {
         VMObjectPaged::wrap(
             VMObjectPagedInner {
-                user_id: id,
+                owner: new_owner_id(),
                 type_: VMOType::Origin,
                 parent: None,
                 parent_offset: 0usize,
@@ -298,16 +298,11 @@ impl VMObjectTrait for VMObjectPaged {
         Ok(())
     }
 
-    fn create_child(
-        &self,
-        offset: usize,
-        len: usize,
-        user_id: KoID,
-    ) -> ZxResult<Arc<dyn VMObjectTrait>> {
+    fn create_child(&self, offset: usize, len: usize) -> ZxResult<Arc<dyn VMObjectTrait>> {
         assert!(page_aligned(offset));
         assert!(page_aligned(len));
         let (_guard, mut inner) = self.get_inner_mut();
-        let child = inner.create_child(offset, len, user_id, &self.lock)?;
+        let child = inner.create_child(offset, len, &self.lock)?;
         Ok(child)
     }
 
@@ -673,12 +668,12 @@ impl VMObjectPagedInner {
             while let Some(vmop) = current {
                 let inner = vmop.inner.borrow();
                 if let Some(frame) = inner.frames.get(&current_idx) {
-                    if frame.tag.is_split() || inner.user_id == self.user_id {
+                    if frame.tag.is_split() || inner.owner == self.owner {
                         count += 1;
                         break;
                     }
                 }
-                if inner.user_id != self.user_id {
+                if inner.owner != self.owner {
                     break;
                 }
                 current_idx += inner.parent_offset / PAGE_SIZE;
@@ -730,7 +725,7 @@ impl VMObjectPagedInner {
         if let Some(parent) = &self.parent {
             parent.inner.borrow_mut().replace_child(
                 &self.self_ref,
-                self.user_id,
+                self.owner,
                 other_child,
                 Some((child.parent_offset, child.parent_limit)),
             );
@@ -743,7 +738,6 @@ impl VMObjectPagedInner {
         &mut self,
         offset: usize,
         len: usize,
-        user_id: KoID,
         lock_ref: &Arc<Mutex<()>>,
     ) -> ZxResult<Arc<VMObjectPaged>> {
         // clone contiguous vmo is no longer permitted
@@ -757,7 +751,7 @@ impl VMObjectPagedInner {
         // create child VMO
         let child = VMObjectPaged::wrap(
             VMObjectPagedInner {
-                user_id,
+                owner: new_owner_id(),
                 type_: VMOType::Snapshot,
                 parent: None, // set later
                 parent_offset: offset,
@@ -775,7 +769,7 @@ impl VMObjectPagedInner {
         // construct a hidden VMO as shared parent
         let hidden = VMObjectPaged::wrap(
             VMObjectPagedInner {
-                user_id: self.user_id,
+                owner: self.owner,
                 type_: VMOType::Hidden {
                     left: self.self_ref.clone(),
                     right: Arc::downgrade(&child),
@@ -873,19 +867,19 @@ impl VMObjectPagedInner {
 
         self.release_unwanted_pages_in_parent(unwanted);
 
-        if old_id == self.user_id {
+        if old_id == self.owner {
             let mut option_parent = self.parent.clone();
             let mut child = self.self_ref.clone();
-            let mut skip_user_id = old_id;
+            let mut skip_owner = old_id;
             while let Some(parent) = option_parent {
                 let mut parent_inner = parent.inner.borrow_mut();
-                if parent_inner.user_id == old_id {
+                if parent_inner.owner == old_id {
                     let (_, other) = parent_inner.type_.get_tag_and_other(&child);
-                    let new_user_id = other.upgrade().unwrap().inner.borrow().user_id;
+                    let new_owner = other.upgrade().unwrap().inner.borrow().owner;
                     child = parent_inner.self_ref.clone();
-                    assert_ne!(new_user_id, skip_user_id);
-                    parent_inner.user_id = new_user_id;
-                    skip_user_id = new_user_id;
+                    assert_ne!(new_owner, skip_owner);
+                    parent_inner.owner = new_owner;
+                    skip_owner = new_owner;
                     option_parent = parent_inner.parent.clone();
                 } else {
                     break;
@@ -893,7 +887,7 @@ impl VMObjectPagedInner {
             }
         }
 
-        self.user_id = other_child.user_id;
+        self.owner = other_child.owner;
         match &mut self.type_ {
             VMOType::Hidden { left, right, .. } => {
                 if left.ptr_eq(old) {
@@ -1043,7 +1037,6 @@ impl Drop for VMObjectPaged {
     }
 }
 
-#[allow(dead_code)]
 /// Generate a owner ID.
 fn new_owner_id() -> u64 {
     static OWNER_ID: AtomicU64 = AtomicU64::new(1);

zircon-object/src/vm/vmo/physical.rs

@@ -86,12 +86,7 @@ impl VMObjectTrait for VMObjectPhysical {
         Ok(())
     }
 
-    fn create_child(
-        &self,
-        _offset: usize,
-        _len: usize,
-        _user_id: KoID,
-    ) -> ZxResult<Arc<dyn VMObjectTrait>> {
+    fn create_child(&self, _offset: usize, _len: usize) -> ZxResult<Arc<dyn VMObjectTrait>> {
         Err(ZxError::NOT_SUPPORTED)
     }
 

zircon-object/src/vm/vmo/slice.rs

@@ -70,12 +70,7 @@ impl VMObjectTrait for VMObjectSlice {
         self.parent.decommit(offset + self.offset, len)
     }
 
-    fn create_child(
-        &self,
-        _offset: usize,
-        _len: usize,
-        _user_id: u64,
-    ) -> ZxResult<Arc<dyn VMObjectTrait>> {
+    fn create_child(&self, _offset: usize, _len: usize) -> ZxResult<Arc<dyn VMObjectTrait>> {
         Err(ZxError::NOT_SUPPORTED)
     }