Reduce some redundant usage of current! and current_thread!

framework/aster-frame/src/task/processor.rs

@@ -61,14 +61,15 @@ pub fn schedule() {
     }
 }
 
-pub fn preempt() {
+// TODO: This interface of this method is error prone.
+// The method takes an argument for the current task to optimize its efficiency,
+// but the argument provided by the caller may not be the current task, really.
+// Thus, this method should be removed or reworked in the future.
+pub fn preempt(task: &Arc<Task>) {
     // TODO: Refactor `preempt` and `schedule`
     // after the Atomic mode and `might_break` is enabled.
-    let Some(curr_task) = current_task() else {
-        return;
-    };
     let mut scheduler = GLOBAL_SCHEDULER.lock_irq_disabled();
-    if !scheduler.should_preempt(&curr_task) {
+    if !scheduler.should_preempt(task) {
         return;
     }
     let Some(next_task) = scheduler.dequeue() else {

kernel/aster-nix/src/process/signal/mod.rs

@@ -30,17 +30,20 @@ use super::posix_thread::{PosixThread, PosixThreadExt};
 use crate::{
     prelude::*,
     process::{do_exit_group, TermStatus},
+    thread::Thread,
     util::{write_bytes_to_user, write_val_to_user},
 };
 
-/// Handle pending signal for current process
-pub fn handle_pending_signal(context: &mut UserContext) -> Result<()> {
-    let current = current!();
-    let current_thread = current_thread!();
-
+// TODO: This interface of this method is error prone.
+// The method takes an argument for the current thread to optimize its efficiency.
+/// Handle pending signal for current process.
+pub fn handle_pending_signal(
+    context: &mut UserContext,
+    current_thread: &Arc<Thread>,
+) -> Result<()> {
     // We first deal with signal in current thread, then signal in current process.
+    let posix_thread = current_thread.as_posix_thread().unwrap();
     let signal = {
-        let posix_thread = current_thread.as_posix_thread().unwrap();
         let sig_mask = *posix_thread.sig_mask().lock();
         if let Some(signal) = posix_thread.dequeue_signal(&sig_mask) {
             signal
@@ -51,6 +54,7 @@ pub fn handle_pending_signal(context: &mut UserContext) -> Result<()> {
 
     let sig_num = signal.num();
     trace!("sig_num = {:?}, sig_name = {}", sig_num, sig_num.sig_name());
+    let current = posix_thread.process();
     let sig_action = current.sig_dispositions().lock().get(sig_num);
     trace!("sig action: {:x?}", sig_action);
     match sig_action {

kernel/aster-nix/src/thread/mod.rs

@@ -61,6 +61,10 @@ impl Thread {
             .expect("[Internal Error] current thread cannot be None")
     }
 
+    pub(in crate::thread) fn task(&self) -> &Arc<Task> {
+        &self.task
+    }
+
     /// Run this thread at once.
     pub fn run(&self) {
         self.status.lock().set_running();

kernel/aster-nix/src/thread/task.rs

@@ -15,8 +15,11 @@ use crate::{
 /// create new task with userspace and parent process
 pub fn create_new_user_task(user_space: Arc<UserSpace>, thread_ref: Weak<Thread>) -> Arc<Task> {
     fn user_task_entry() {
-        let cur = Task::current();
-        let user_space = cur.user_space().expect("user task should have user space");
+        let current_thread = current_thread!();
+        let current_task = current_thread.task();
+        let user_space = current_task
+            .user_space()
+            .expect("user task should have user space");
         let mut user_mode = UserMode::new(user_space);
         debug!(
             "[Task entry] rip = 0x{:x}",
@@ -30,17 +33,17 @@ pub fn create_new_user_task(user_space: Arc<UserSpace>, thread_ref: Weak<Thread>
             "[Task entry] rax = 0x{:x}",
             user_mode.context().syscall_ret()
         );
+
         loop {
             let user_event = user_mode.execute();
             let context = user_mode.context_mut();
             // handle user event:
             handle_user_event(user_event, context);
-            let current_thread = current_thread!();
             // should be do this comparison before handle signal?
             if current_thread.status().lock().is_exited() {
                 break;
             }
-            handle_pending_signal(context).unwrap();
+            handle_pending_signal(context, &current_thread).unwrap();
             if current_thread.status().lock().is_exited() {
                 debug!("exit due to signal");
                 break;
@@ -49,14 +52,14 @@ pub fn create_new_user_task(user_space: Arc<UserSpace>, thread_ref: Weak<Thread>
             while current_thread.status().lock().is_stopped() {
                 Thread::yield_now();
                 debug!("{} is suspended.", current_thread.tid());
-                handle_pending_signal(context).unwrap();
+                handle_pending_signal(context, &current_thread).unwrap();
             }
             // a preemption point after handling user event.
-            preempt();
+            preempt(current_task);
         }
         debug!("exit user loop");
         // FIXME: This is a work around: exit in kernel task entry may be not called. Why this will happen?
-        Task::current().exit();
+        current_task.exit();
     }
 
     TaskOptions::new(user_task_entry)