vmm: remove unused mutex in api

This patch removes locks in VmCreate request and VmInfo response
since we needn't use a lock here and should ensure that internal
implementation is transparent to the runtime.

Signed-off-by: Songqian Li <sionli@tencent.com>

vmm/src/api/dbus/mod.rs

@@ -20,7 +20,7 @@ use hypervisor::HypervisorType;
 use seccompiler::{apply_filter, SeccompAction};
 use std::panic::AssertUnwindSafe;
 use std::sync::mpsc::Sender;
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 use std::thread;
 use vmm_sys_util::eventfd::EventFd;
 use zbus::fdo::{self, Result};
@@ -201,7 +201,7 @@ impl DBusApi {
         let api_sender = self.clone_api_sender().await;
         let api_notifier = self.clone_api_notifier()?;
 
-        let mut vm_config: VmConfig = serde_json::from_str(&vm_config).map_err(api_error)?;
+        let mut vm_config: Box<VmConfig> = serde_json::from_str(&vm_config).map_err(api_error)?;
 
         if let Some(ref mut nets) = vm_config.net {
             if nets.iter().any(|net| net.fds.is_some()) {
@@ -212,11 +212,9 @@ impl DBusApi {
             }
         }
 
-        blocking::unblock(move || {
-            VmCreate.send(api_notifier, api_sender, Arc::new(Mutex::new(vm_config)))
-        })
-        .await
-        .map_err(api_error)?;
+        blocking::unblock(move || VmCreate.send(api_notifier, api_sender, vm_config))
+            .await
+            .map_err(api_error)?;
 
         Ok(())
     }

vmm/src/api/http/http_endpoint.rs

@@ -18,7 +18,6 @@ use micro_http::{Body, Method, Request, Response, StatusCode, Version};
 use std::fs::File;
 use std::os::unix::io::IntoRawFd;
 use std::sync::mpsc::Sender;
-use std::sync::{Arc, Mutex};
 use vmm_sys_util::eventfd::EventFd;
 
 // /api/v1/vm.create handler
@@ -36,7 +35,7 @@ impl EndpointHandler for VmCreate {
                 match &req.body {
                     Some(body) => {
                         // Deserialize into a VmConfig
-                        let mut vm_config: VmConfig = match serde_json::from_slice(body.raw())
+                        let mut vm_config: Box<VmConfig> = match serde_json::from_slice(body.raw())
                             .map_err(HttpError::SerdeJsonDeserialize)
                         {
                             Ok(config) => config,
@@ -53,7 +52,7 @@ impl EndpointHandler for VmCreate {
                         }
 
                         match crate::api::VmCreate
-                            .send(api_notifier, api_sender, Arc::new(Mutex::new(vm_config)))
+                            .send(api_notifier, api_sender, vm_config)
                             .map_err(HttpError::ApiError)
                         {
                             Ok(_) => Response::new(Version::Http11, StatusCode::NoContent),

vmm/src/api/mod.rs

@@ -51,7 +51,6 @@ use serde::{Deserialize, Serialize};
 use std::fmt::Display;
 use std::io;
 use std::sync::mpsc::{channel, RecvError, SendError, Sender};
-use std::sync::{Arc, Mutex};
 use vm_migration::MigratableError;
 use vmm_sys_util::eventfd::EventFd;
 
@@ -210,10 +209,10 @@ impl Display for ApiError {
 
 #[derive(Clone, Deserialize, Serialize)]
 pub struct VmInfoResponse {
-    pub config: Arc<Mutex<VmConfig>>,
+    pub config: Box<VmConfig>,
     pub state: VmState,
     pub memory_actual_size: u64,
-    pub device_tree: Option<Arc<Mutex<DeviceTree>>>,
+    pub device_tree: Option<DeviceTree>,
 }
 
 #[derive(Clone, Deserialize, Serialize)]
@@ -287,7 +286,7 @@ pub enum ApiResponsePayload {
 pub type ApiResponse = Result<ApiResponsePayload, ApiError>;
 
 pub trait RequestHandler {
-    fn vm_create(&mut self, config: Arc<Mutex<VmConfig>>) -> Result<(), VmError>;
+    fn vm_create(&mut self, config: Box<VmConfig>) -> Result<(), VmError>;
 
     fn vm_boot(&mut self) -> Result<(), VmError>;
 
@@ -827,7 +826,7 @@ impl ApiAction for VmCounters {
 pub struct VmCreate;
 
 impl ApiAction for VmCreate {
-    type RequestBody = Arc<Mutex<VmConfig>>;
+    type RequestBody = Box<VmConfig>;
     type ResponseBody = ();
 
     fn request(