vring: introduce trait VringT

Introduce trait VringT, and provide three implementations of it:
VringState, VringMutex, VringRwLock.

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

Author: jiangliu

src/backend.rs

@@ -28,7 +28,7 @@ use vhost::vhost_user::SlaveFsCacheReq;
 use vm_memory::bitmap::Bitmap;
 use vmm_sys_util::eventfd::EventFd;
 
-use super::{Vring, GM};
+use super::{VringRwLock, GM};
 
 /// Trait with interior mutability for vhost user backend servers to implement concrete services.
 ///
@@ -107,7 +107,7 @@ pub trait VhostUserBackend<B: Bitmap + 'static = ()>: Send + Sync + 'static {
         &self,
         device_event: u16,
         evset: epoll::Events,
-        vrings: &[Vring<GM<B>>],
+        vrings: &[VringRwLock<GM<B>>],
         thread_id: usize,
     ) -> result::Result<bool, io::Error>;
 }
@@ -186,7 +186,7 @@ pub trait VhostUserBackendMut<B: Bitmap + 'static = ()>: Send + Sync + 'static {
         &mut self,
         device_event: u16,
         evset: epoll::Events,
-        vrings: &[Vring<GM<B>>],
+        vrings: &[VringRwLock<GM<B>>],
         thread_id: usize,
     ) -> result::Result<bool, io::Error>;
 }
@@ -244,7 +244,7 @@ impl<T: VhostUserBackend<B>, B: Bitmap + 'static> VhostUserBackend<B> for Arc<T>
         &self,
         device_event: u16,
         evset: epoll::Events,
-        vrings: &[Vring<GM<B>>],
+        vrings: &[VringRwLock<GM<B>>],
         thread_id: usize,
     ) -> Result<bool, io::Error> {
         self.deref()
@@ -305,7 +305,7 @@ impl<T: VhostUserBackendMut<B>, B: Bitmap + 'static> VhostUserBackend<B> for Mut
         &self,
         device_event: u16,
         evset: epoll::Events,
-        vrings: &[Vring<GM<B>>],
+        vrings: &[VringRwLock<GM<B>>],
         thread_id: usize,
     ) -> Result<bool, io::Error> {
         self.lock()
@@ -367,7 +367,7 @@ impl<T: VhostUserBackendMut<B>, B: Bitmap + 'static> VhostUserBackend<B> for RwL
         &self,
         device_event: u16,
         evset: epoll::Events,
-        vrings: &[Vring<GM<B>>],
+        vrings: &[VringRwLock<GM<B>>],
         thread_id: usize,
     ) -> Result<bool, io::Error> {
         self.write()
@@ -463,7 +463,7 @@ pub mod tests {
             &mut self,
             _device_event: u16,
             _evset: Events,
-            _vrings: &[Vring],
+            _vrings: &[VringRwLock],
             _thread_id: usize,
         ) -> Result<bool, Error> {
             self.events += 1;

src/event_loop.rs

@@ -12,7 +12,8 @@ use std::result;
 use vm_memory::bitmap::Bitmap;
 use vmm_sys_util::eventfd::EventFd;
 
-use super::{VhostUserBackend, Vring, GM};
+use super::vring::VringT;
+use super::{VhostUserBackend, VringRwLock, GM};
 
 /// Errors related to vring epoll event handling.
 #[derive(Debug)]
@@ -59,7 +60,7 @@ pub type VringEpollResult<T> = std::result::Result<T, VringEpollError>;
 pub struct VringEpollHandler<S: VhostUserBackend<B>, B: Bitmap + 'static> {
     epoll_file: File,
     backend: S,
-    vrings: Vec<Vring<GM<B>>>,
+    vrings: Vec<VringRwLock<GM<B>>>,
     thread_id: usize,
     exit_event_fd: Option<EventFd>,
     exit_event_id: Option<u16>,
@@ -69,7 +70,7 @@ impl<S: VhostUserBackend<B>, B: Bitmap + 'static> VringEpollHandler<S, B> {
     /// Create a `VringEpollHandler` instance.
     pub(crate) fn new(
         backend: S,
-        vrings: Vec<Vring<GM<B>>>,
+        vrings: Vec<VringRwLock<GM<B>>>,
         thread_id: usize,
     ) -> VringEpollResult<Self> {
         let epoll_fd = epoll::create(true).map_err(VringEpollError::EpollCreateFd)?;
@@ -234,7 +235,7 @@ mod tests {
         let mem = GuestMemoryAtomic::new(
             GuestMemoryMmap::<()>::from_ranges(&[(GuestAddress(0x100000), 0x10000)]).unwrap(),
         );
-        let vring = Vring::new(mem, 0x1000);
+        let vring = VringRwLock::new(mem, 0x1000);
         let backend = Arc::new(Mutex::new(MockVhostBackend::new()));
 
         let handler = VringEpollHandler::new(backend, vec![vring], 0x1).unwrap();

src/handler.rs

@@ -15,14 +15,22 @@ use vhost::vhost_user::message::{
     VhostUserSingleMemoryRegion, VhostUserVirtioFeatures, VhostUserVringAddrFlags,
     VhostUserVringState,
 };
-use vhost::vhost_user::{Error as VhostUserError, Result as VhostUserResult, SlaveFsCacheReq};
+use vhost::vhost_user::{
+    Error as VhostUserError, Result as VhostUserResult, SlaveFsCacheReq,
+    VhostUserSlaveReqHandlerMut,
+};
 use virtio_bindings::bindings::virtio_ring::VIRTIO_RING_F_EVENT_IDX;
 use vm_memory::bitmap::Bitmap;
 use vm_memory::mmap::NewBitmap;
-use vm_memory::{FileOffset, GuestAddress, GuestMemoryMmap, GuestRegionMmap};
+use vm_memory::{
+    FileOffset, GuestAddress, GuestAddressSpace, GuestMemoryMmap, GuestRegionMmap, MmapRegion,
+};
 
+use super::backend::VhostUserBackend;
+use super::event_loop::VringEpollHandler;
 use super::event_loop::{VringEpollError, VringEpollResult};
-use super::*;
+use super::vring::{VringRwLock, VringT};
+use super::GM;
 
 const MAX_MEM_SLOTS: u64 = 32;
 
@@ -74,7 +82,7 @@ pub struct VhostUserHandler<S: VhostUserBackend<B>, B: Bitmap + 'static> {
     queues_per_thread: Vec<u64>,
     mappings: Vec<AddrMapping>,
     atomic_mem: GM<B>,
-    vrings: Vec<Vring<GM<B>>>,
+    vrings: Vec<VringRwLock<GM<B>>>,
     worker_threads: Vec<thread::JoinHandle<VringEpollResult<()>>>,
 }
 
@@ -86,7 +94,7 @@ impl<S: VhostUserBackend<B> + Clone, B: Bitmap + Clone + Send + Sync> VhostUserH
 
         let mut vrings = Vec::new();
         for _ in 0..num_queues {
-            let vring = Vring::new(atomic_mem.clone(), max_queue_size as u16);
+            let vring = VringRwLock::new(atomic_mem.clone(), max_queue_size as u16);
             vrings.push(vring);
         }
 
@@ -194,7 +202,7 @@ impl<S: VhostUserBackend<B>, B: NewBitmap + Clone> VhostUserSlaveReqHandlerMut
         // been disabled by VHOST_USER_SET_VRING_ENABLE with parameter 0.
         let vring_enabled =
             self.acked_features & VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits() == 0;
-        for vring in self.vrings.iter() {
+        for vring in self.vrings.iter_mut() {
             vring.set_enabled(vring_enabled);
         }
 

src/lib.rs

@@ -14,12 +14,10 @@ use std::result;
 use std::sync::{Arc, Mutex};
 use std::thread;
 
-use vhost::vhost_user::{
-    Error as VhostUserError, Listener, SlaveListener, VhostUserSlaveReqHandlerMut,
-};
+use vhost::vhost_user::{Error as VhostUserError, Listener, SlaveListener};
 use vm_memory::bitmap::Bitmap;
 use vm_memory::mmap::NewBitmap;
-use vm_memory::{GuestAddressSpace, GuestMemoryAtomic, GuestMemoryMmap, MmapRegion};
+use vm_memory::{GuestMemoryAtomic, GuestMemoryMmap};
 
 use self::handler::VhostUserHandler;
 
@@ -33,7 +31,7 @@ mod handler;
 pub use self::handler::VhostUserHandlerError;
 
 mod vring;
-pub use self::vring::{Vring, VringState};
+pub use self::vring::{VringRwLock, VringState};
 
 /// An alias for `GuestMemoryAtomic<GuestMemoryMmap<B>>` to simplify code.
 type GM<B> = GuestMemoryAtomic<GuestMemoryMmap<B>>;