queue: add size() to QueueStateT

Add method size() to QueueStateT.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>

Author: jiangliu

crates/virtio-queue/CHANGELOG.md

@@ -1,3 +1,11 @@
+# Unreleased
+
+## Added
+- QueueStateT::size(): [#153](https://github.com/rust-vmm/vm-virtio/pull/153)
+
+## Removed
+- #[derive(Clone)] for QueueState: [#153](https://github.com/rust-vmm/vm-virtio/pull/153)
+
 # v0.2.0
 
 ## Added
@@ -13,4 +21,4 @@
 
 # v0.1.0
 
-This is the first release of the crate.
+This is the first release of the crate.

crates/virtio-queue/src/lib.rs

@@ -121,6 +121,9 @@ pub trait QueueStateT: for<'a> QueueStateGuard<'a> {
     /// Get the maximum size of the virtio queue.
     fn max_size(&self) -> u16;
 
+    /// Get the actual size configured by the guest.
+    fn size(&self) -> u16;
+
     /// Configure the queue size for the virtio queue.
     fn set_size(&mut self, size: u16);
 

crates/virtio-queue/src/state.rs

@@ -242,6 +242,10 @@ impl QueueStateT for QueueState {
         self.max_size
     }
 
+    fn size(&self) -> u16 {
+        self.size
+    }
+
     fn set_size(&mut self, size: u16) {
         if size > self.max_size() || size == 0 || (size & (size - 1)) != 0 {
             error!("virtio queue with invalid size: {}", size);
@@ -427,14 +431,14 @@ impl QueueStateT for QueueState {
         self.next_avail.0
     }
 
-    fn next_used(&self) -> u16 {
-        self.next_used.0
-    }
-
     fn set_next_avail(&mut self, next_avail: u16) {
         self.next_avail = Wrapping(next_avail);
     }
 
+    fn next_used(&self) -> u16 {
+        self.next_used.0
+    }
+
     fn set_next_used(&mut self, next_used: u16) {
         self.next_used = Wrapping(next_used);
     }

crates/virtio-queue/src/state_sync.rs

@@ -75,6 +75,10 @@ impl QueueStateT for QueueStateSync {
         self.lock_state().max_size()
     }
 
+    fn size(&self) -> u16 {
+        self.lock_state().size()
+    }
+
     fn set_size(&mut self, size: u16) {
         self.lock_state().set_size(size);
     }
@@ -136,14 +140,14 @@ impl QueueStateT for QueueStateSync {
         self.lock_state().next_avail()
     }
 
-    fn next_used(&self) -> u16 {
-        self.lock_state().next_used()
-    }
-
     fn set_next_avail(&mut self, next_avail: u16) {
         self.lock_state().set_next_avail(next_avail);
     }
 
+    fn next_used(&self) -> u16 {
+        self.lock_state().next_used()
+    }
+
     fn set_next_used(&mut self, next_used: u16) {
         self.lock_state().set_next_used(next_used);
     }
@@ -210,7 +214,9 @@ mod tests {
         assert_eq!(q.lock().size, 0x100);
 
         assert_eq!(q.max_size(), 0x100);
+        assert_eq!(q.size(), 0x100);
         q.set_size(0x80);
+        assert_eq!(q.size(), 0x80);
         assert_eq!(q.max_size(), 0x100);
         q.set_next_avail(5);
         assert_eq!(q.next_avail(), 5);