void up(struct semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->lock, flags);
if (likely(list_empty(&sem->wait_list)))
sem->count++;
else
__up(sem);
spin_unlock_irqrestore(&sem->lock, flags);
}
void
up(struct semaphore *sem)
{
#ifdef WAITQUEUE_DEBUG
CHECK_MAGIC(sem->__magic);
#endif
#ifdef CONFIG_DEBUG_SEMAPHORE
printk("%s(%d): up(%p) <count=%d> from %p\n",
current->comm, current->pid, sem,
atomic_read(&sem->count), __builtin_return_address(0));
#endif
__up(sem);
}
/**
* up :释放信号量
* @sem: the semaphore to release
*/
void up(struct semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->lock, flags);
/*没有其他进程在等待sem信号量,则直接递增cout的值
* 直接返回*/
if (likely(list_empty(&sem->wait_list)))
sem->count++;
else
__up(sem);
spin_unlock_irqrestore(&sem->lock, flags);
}
/**
* up - release the semaphore
* @sem: the semaphore to release
*
* Release the semaphore. Unlike mutexes, up() may be called from any
* context and even by tasks which have never called down().
*/
void up(struct semaphore *sem)
{
unsigned long flags;
spin_lock_irqsave(&sem->lock, flags);
#ifdef CONFIG_MT_LOCK_DEBUG
if(0 == sem->count)
sem_clear_owner(sem);
#endif
if (likely(list_empty(&sem->wait_list))){
sem->count++;
}else
__up(sem);
spin_unlock_irqrestore(&sem->lock, flags);
}
/**
* up - release the semaphore
* @sem: the semaphore to release
*
* Release the semaphore. Unlike mutexes, up() may be called from any
* context and even by tasks which have never called down().
*/
void up(struct semaphore *sem)
{
unsigned long flags;
raw_spin_lock_irqsave(&sem->lock, flags);
#ifdef CONFIG_ILOCKDEP
ilockdep_release(&sem->idep_map, _RET_IP_, (void *)sem);
#endif
if (likely(list_empty(&sem->wait_list)))
sem->count++;
else
__up(sem);
raw_spin_unlock_irqrestore(&sem->lock, flags);
}
void
up(semaphore_t *sem) {
__up(sem, WT_KSEM);
}
static void
usem_up(semaphore_t *sem) {
__up(sem, WT_USEM);
}
static int
usem_up(semaphore_t *sem) {
__up(sem, WT_USEM);
return 0;
}
