turn off syscall printing, remove unused imports and make fmt

kernel/src/driver/net/loopback.rs

@@ -52,7 +52,7 @@ impl phy::RxToken for LoopbackRxToken {
     /// 返回函数 `f` 在 `self.buffer` 上的调用结果。
     fn consume<R, F>(self, f: F) -> R
     where
-        F: FnOnce(&[u8]) -> R
+        F: FnOnce(&[u8]) -> R,
     {
         f(self.buffer.as_slice())
     }
@@ -277,7 +277,7 @@ impl LoopbackInterface {
     /// 返回一个 `Arc<Self>`，即一个指向新创建的 `LoopbackInterface` 实例的智能指针。
     pub fn new(mut driver: LoopbackDriver) -> Arc<Self> {
         let iface_id = generate_iface_id();
-        
+
         let hardware_addr = HardwareAddress::Ethernet(smoltcp::wire::EthernetAddress([
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         ]));
@@ -296,9 +296,7 @@ impl LoopbackInterface {
 
         //设置网卡地址为127.0.0.1
         iface.update_ip_addrs(|ip_addrs| {
-            ip_addrs
-                .push(cidr)
-                .expect("Push ipCidr failed: full");
+            ip_addrs.push(cidr).expect("Push ipCidr failed: full");
         });
 
         iface.routes_mut().update(|routes_map| {

kernel/src/driver/net/mod.rs

@@ -211,9 +211,9 @@ impl IfaceCommon {
         let (has_events, poll_at) = {
             (
                 matches!(
-                    interface.poll(timestamp, device, &mut sockets), 
+                    interface.poll(timestamp, device, &mut sockets),
                     smoltcp::iface::PollResult::SocketStateChanged
-                ), 
+                ),
                 loop {
                     let poll_at = interface.poll_at(timestamp, &sockets);
                     let Some(instant) = poll_at else {
@@ -222,7 +222,7 @@ impl IfaceCommon {
                     if instant > timestamp {
                         break poll_at;
                     }
-                }
+                },
             )
         };