Pipe OK.

os/src/fs/mod.rs

@@ -11,10 +11,11 @@ pub trait File : Any + Send + Sync {
 }
 
 impl dyn File {
+    #[allow(unused)]
     pub fn downcast_ref<T: File>(&self) -> Option<&T> {
         self.as_any_ref().downcast_ref::<T>()
     }
 }
 
-pub use pipe::{Pipe};
+pub use pipe::{Pipe, make_pipe};
 pub use stdio::{Stdin, Stdout};

os/src/fs/pipe.rs

@@ -44,7 +44,7 @@ pub struct PipeRingBuffer {
     head: usize,
     tail: usize,
     status: RingBufferStatus,
-    write_end: Option<Weak<Mutex<Pipe>>>,
+    write_end: Option<Weak<Pipe>>,
 }
 
 impl PipeRingBuffer {
@@ -57,7 +57,7 @@ impl PipeRingBuffer {
             write_end: None,
         }
     }
-    pub fn set_write_end(&mut self, write_end: &Arc<Mutex<Pipe>>) {
+    pub fn set_write_end(&mut self, write_end: &Arc<Pipe>) {
         self.write_end = Some(Arc::downgrade(write_end));
     }
     pub fn write_byte(&mut self, byte: u8) {
@@ -101,14 +101,14 @@ impl PipeRingBuffer {
 }
 
 /// Return (read_end, write_end)
-pub fn make_pipe() -> (Arc<Mutex<Pipe>>, Arc<Mutex<Pipe>>) {
+pub fn make_pipe() -> (Arc<Pipe>, Arc<Pipe>) {
     let buffer = Arc::new(Mutex::new(PipeRingBuffer::new()));
-    let read_end = Arc::new(Mutex::new(
+    let read_end = Arc::new(
         Pipe::read_end_with_buffer(buffer.clone())
-    ));
-    let write_end = Arc::new(Mutex::new(
+    );
+    let write_end = Arc::new(
         Pipe::write_end_with_buffer(buffer.clone())
-    ));
+    );
     buffer.lock().set_write_end(&write_end);
     (read_end, write_end)
 }

os/src/fs/stdio.rs

@@ -1,5 +1,5 @@
 use super::File;
-use crate::mm::{UserBuffer, UserBufferIterator};
+use crate::mm::{UserBuffer};
 use crate::sbi::console_getchar;
 use crate::task::suspend_current_and_run_next;
 use core::any::Any;