2022-07-31 17:09:12 +08:00

120 lines
2.5 KiB
C

#include <common/mutex.h>
#include <mm/slab.h>
#include <sched/sched.h>
/**
* @brief 初始化互斥量
*
* @param lock mutex结构体
*/
void mutex_init(mutex_t *lock)
{
atomic_set(&lock->count, 1);
spin_init(&lock->wait_lock);
list_init(&lock->wait_list);
}
static void __mutex_sleep()
{
current_pcb->state = PROC_UNINTERRUPTIBLE;
sched_cfs();
}
static void __mutex_acquire(mutex_t *lock)
{
}
/**
* @brief 对互斥量加锁
*
* @param lock mutex结构体
*/
void mutex_lock(mutex_t *lock)
{
bool lock_ok = 0;
while (lock_ok == false)
{
spin_lock(&lock->wait_lock);
if (likely(mutex_is_locked(lock)))
{
struct mutex_waiter_t *waiter = (struct mutex_waiter_t *)kmalloc(sizeof(struct mutex_waiter_t), 0);
if (waiter == NULL)
{
kerror("In mutex_lock: no memory to alloc waiter. Program's behaviour might be indetermined!");
spin_unlock(&lock->wait_lock);
return;
}
memset(waiter, 0, sizeof(struct mutex_waiter_t));
waiter->pcb = current_pcb;
list_init(&waiter->list);
list_append(&lock->wait_list, &waiter->list);
spin_unlock(&lock->wait_lock);
__mutex_sleep();
}
else
{
atomic_dec(&lock->count);
spin_unlock(&lock->wait_lock);
lock_ok = true;
}
}
}
/**
* @brief 对互斥量解锁
*
* @param lock mutex结构体
*/
void mutex_unlock(mutex_t *lock)
{
if (unlikely(!mutex_is_locked(lock)))
return;
spin_lock(&lock->wait_lock);
struct mutex_waiter_t *wt = NULL;
if (mutex_is_locked(lock))
{
if (!list_empty(&lock->wait_list))
wt = container_of(list_next(&lock->wait_list), struct mutex_waiter_t, list);
atomic_inc(&lock->count);
if (wt != NULL)
list_del(&wt->list);
}
spin_unlock(&lock->wait_lock);
if (wt != NULL)
{
process_wakeup(wt->pcb);
kfree(wt);
}
}
/**
* @brief 尝试对互斥量加锁
*
* @param lock mutex结构体
*
* @return 成功加锁->1, 加锁失败->0
*/
int mutex_trylock(mutex_t *lock)
{
if (mutex_is_locked(lock))
return 0;
spin_lock(&lock->wait_lock);
if (mutex_is_locked(lock))
{
spin_unlock(&lock->wait_lock);
return 0;
}
else
{
atomic_dec(&lock->count);
spin_unlock(&lock->wait_lock);
return 1;
}
}