From 458f6f42f69a99cefd4c53ab0d279a5e56dec84c Mon Sep 17 00:00:00 2001
From: xuejun-xj <jiyunxue@alibaba.linux.com>
Date: Mon, 11 Jul 2022 17:46:10 +0800
Subject: [PATCH] dragonball: use const string for legacy device type

As string "com1", "com2" and "rtc" are used in two files
(device_manager/mod.rs and device_manager/legacy.rs), we use public
const variables COM1, COM2 and RTC to replace them respectively.

Fixes: #4544

Signed-off-by: xuejun-xj <jiyunxue@alibaba.linux.com>
Signed-off-by: jingshan <jingshan@linux.alibaba.com>
---
 src/dragonball/src/device_manager/legacy.rs | 14 +++++++++++---
 src/dragonball/src/device_manager/mod.rs    |  8 ++++----
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/dragonball/src/device_manager/legacy.rs b/src/dragonball/src/device_manager/legacy.rs
index b3e33a7f22..59f4206ab9 100644
--- a/src/dragonball/src/device_manager/legacy.rs
+++ b/src/dragonball/src/device_manager/legacy.rs
@@ -156,18 +156,26 @@ pub(crate) mod aarch64 {
 
     type Result<T> = ::std::result::Result<T, Error>;
 
+    /// LegacyDeviceType: com1
+    pub const COM1: &str = "com1";
+    /// LegacyDeviceType: com2
+    pub const COM2: &str = "com2";
+    /// LegacyDeviceType: rtc
+    pub const RTC: &str = "rtc";
+
     impl LegacyDeviceManager {
+        /// Create a LegacyDeviceManager instance handling legacy devices.
         pub fn create_manager(
             bus: &mut IoManager,
             vm_fd: Option<Arc<VmFd>>,
             resources: &HashMap<String, DeviceResources>,
         ) -> Result<Self> {
             let (com1_device, com1_eventfd) =
-                Self::create_com_device(bus, vm_fd.as_ref(), resources.get("com1").unwrap())?;
+                Self::create_com_device(bus, vm_fd.as_ref(), resources.get(COM1).unwrap())?;
             let (com2_device, com2_eventfd) =
-                Self::create_com_device(bus, vm_fd.as_ref(), resources.get("com2").unwrap())?;
+                Self::create_com_device(bus, vm_fd.as_ref(), resources.get(COM2).unwrap())?;
             let (rtc_device, rtc_eventfd) =
-                Self::create_rtc_device(bus, vm_fd.as_ref(), resources.get("rtc").unwrap())?;
+                Self::create_rtc_device(bus, vm_fd.as_ref(), resources.get(RTC).unwrap())?;
 
             Ok(LegacyDeviceManager {
                 _rtc_device: rtc_device,
diff --git a/src/dragonball/src/device_manager/mod.rs b/src/dragonball/src/device_manager/mod.rs
index 1e52600e5d..d9d03947d1 100644
--- a/src/dragonball/src/device_manager/mod.rs
+++ b/src/dragonball/src/device_manager/mod.rs
@@ -54,7 +54,7 @@ pub mod console_manager;
 pub use self::console_manager::ConsoleManager;
 
 mod legacy;
-pub use self::legacy::{Error as LegacyDeviceError, LegacyDeviceManager};
+pub use self::legacy::{Error as LegacyDeviceError, LegacyDeviceManager, aarch64::{COM1, COM2, RTC}};
 
 #[cfg(feature = "virtio-vsock")]
 /// Device manager for user-space vsock devices.
@@ -744,9 +744,9 @@ impl DeviceManager {
     ) -> std::result::Result<HashMap<String, DeviceResources>, StartMicroVmError> {
         let mut resources = HashMap::new();
         let legacy_devices = vec![
-            (DeviceType::Serial, String::from("com1")),
-            (DeviceType::Serial, String::from("com2")),
-            (DeviceType::RTC, String::from("rtc")),
+            (DeviceType::Serial, String::from(COM1)),
+            (DeviceType::Serial, String::from(COM2)),
+            (DeviceType::RTC, String::from(RTC)),
         ];
 
         for (device_type, device_id) in legacy_devices {