From ab1891c62f00e4a3728888446f8bb6fbbe5bd087 Mon Sep 17 00:00:00 2001
From: acevest <zhaoyanbai@126.com>
Date: Sat, 20 May 2023 14:26:13 +0800
Subject: [PATCH] =?utf8?q?=E5=88=A0=E9=99=A4semaphore=20=5F=5Fdown?=
 =?utf8?q?=E9=87=8C=E7=9A=84enable=5Firq=E5=92=8Cdisable=5Firq?=
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---
 include/system.h   |  2 +-
 kernel/semaphore.c | 13 +++++--------
 kernel/system.c    |  2 +-
 kernel/wait.c      | 19 +++++++++++--------
 4 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/include/system.h b/include/system.h
index f30d7cc..3e56a3e 100644
--- a/include/system.h
+++ b/include/system.h
@@ -267,7 +267,7 @@ void init_task_entry();
 void disk_task_entry();
 void user_task_entry();
 
-extern int irq_reenter;
+extern volatile int irq_reenter;
 #endif
 
 #endif  //_SYSTEM_H
diff --git a/kernel/semaphore.c b/kernel/semaphore.c
index 857dca1..55360e8 100644
--- a/kernel/semaphore.c
+++ b/kernel/semaphore.c
@@ -21,7 +21,7 @@ typedef struct semaphore_waiter {
 
 #define DECLARE_SEMAPHORE_WAITER(name, task) semaphore_waiter_t name = SEMAPHORE_WAITER_INITIALIZER(name, task)
 
-void __down(semaphore_t *s) {
+volatile void __down(semaphore_t *s) {
     task_union *task = current;
     DECLARE_SEMAPHORE_WAITER(waiter, task);
     list_add_tail(&waiter.list, &s->wait_list);
@@ -29,21 +29,18 @@ void __down(semaphore_t *s) {
     while (true) {
         task->state = TASK_WAIT;
 
-        enable_irq();
-
         schedule();
 
-        disable_irq();
-
         if (waiter.up) {
             break;
         }
     }
 }
 
-void down(semaphore_t *s) {
+volatile void down(semaphore_t *s) {
     unsigned long iflags;
     irq_save(iflags);
+
     if (likely(s->cnt > 0)) {
         s->cnt--;
     } else {
@@ -53,7 +50,7 @@ void down(semaphore_t *s) {
     irq_restore(iflags);
 }
 
-void __up(semaphore_t *s) {
+volatile void __up(semaphore_t *s) {
     semaphore_waiter_t *waiter = list_first_entry(&s->wait_list, semaphore_waiter_t, list);
     list_del(&waiter->list);
     waiter->up = 1;
@@ -61,7 +58,7 @@ void __up(semaphore_t *s) {
     waiter->task->state = TASK_READY;
 }
 
-void up(semaphore_t *s) {
+volatile void up(semaphore_t *s) {
     unsigned long iflags;
     irq_save(iflags);
 
diff --git a/kernel/system.c b/kernel/system.c
index 48dded1..56183d9 100644
--- a/kernel/system.c
+++ b/kernel/system.c
@@ -192,4 +192,4 @@ Desc gdt[NGDT] __attribute__((__aligned__(8)));
 char gdtr[6] __attribute__((__aligned__(4)));
 char idtr[6] __attribute__((__aligned__(4)));
 
-int irq_reenter = 0x00;
\ No newline at end of file
+volatile int irq_reenter = 0x00;
\ No newline at end of file
diff --git a/kernel/wait.c b/kernel/wait.c
index a94aca8..a89f2f2 100644
--- a/kernel/wait.c
+++ b/kernel/wait.c
@@ -12,23 +12,23 @@
 #include <sched.h>
 #include <wait.h>
 
-void init_wait_queue_head(wait_queue_head_t *wqh) { INIT_LIST_HEAD(&wqh->task_list); }
+volatile void init_wait_queue_head(wait_queue_head_t *wqh) { INIT_LIST_HEAD(&wqh->task_list); }
 
-void add_wait_queue(wait_queue_head_t *head, wait_queue_t *wq) {
+volatile void add_wait_queue(wait_queue_head_t *head, wait_queue_t *wq) {
     unsigned long flags;
     irq_save(flags);
     list_add_tail(&wq->task_list, &head->task_list);
     irq_restore(flags);
 }
 
-void del_wait_queue(wait_queue_head_t *head, wait_queue_t *wq) {
+volatile void del_wait_queue(wait_queue_head_t *head, wait_queue_t *wq) {
     unsigned long flags;
     irq_save(flags);
     list_del(&wq->task_list);
     irq_restore(flags);
 }
 
-void prepare_to_wait(wait_queue_head_t *head, wait_queue_t *wq, unsigned int state) {
+volatile void prepare_to_wait(wait_queue_head_t *head, wait_queue_t *wq, unsigned int state) {
     unsigned long flags;
     irq_save(flags);
     if (list_empty(&wq->task_list)) {
@@ -38,7 +38,7 @@ void prepare_to_wait(wait_queue_head_t *head, wait_queue_t *wq, unsigned int sta
     irq_restore(flags);
 }
 
-void __end_wait(wait_queue_head_t *head, wait_queue_t *wq) {
+volatile void __end_wait(wait_queue_head_t *head, wait_queue_t *wq) {
     set_current_state(TASK_READY);
     unsigned long flags;
     irq_save(flags);
@@ -46,7 +46,7 @@ void __end_wait(wait_queue_head_t *head, wait_queue_t *wq) {
     irq_restore(flags);
 }
 
-void sleep_on(wait_queue_head_t *head) {
+volatile void sleep_on(wait_queue_head_t *head) {
     DECLARE_WAIT_QUEUE(wait, current);
 
     unsigned long flags;
@@ -59,9 +59,12 @@ void sleep_on(wait_queue_head_t *head) {
     irq_restore(flags);
 
     schedule();
+
+    // wake_up操作会把wait从heat链表上删除
+    // 所以这里就不用做什么了
 }
 
-void __wake_up(wait_queue_head_t *head, int nr) {
+volatile void __wake_up(wait_queue_head_t *head, int nr) {
     unsigned long flags;
     wait_queue_t *p, *tmp;
     irq_save(flags);
@@ -80,7 +83,7 @@ void __wake_up(wait_queue_head_t *head, int nr) {
     // no schedule() here.
 }
 
-void wake_up(wait_queue_head_t *head) { __wake_up(head, 1); }
+volatile void wake_up(wait_queue_head_t *head) { __wake_up(head, 1); }
 
 #include <irq.h>
 DECLARE_WAIT_QUEUE_HEAD(debug_wq);
-- 
2.44.0