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@@ -54,10 +54,9 @@ void down(struct semaphore *sem)
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unsigned long flags;
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spin_lock_irqsave(&sem->lock, flags);
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- if (likely(sem->count > 0))
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- sem->count--;
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- else
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+ if (unlikely(!sem->count))
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__down(sem);
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+ sem->count--;
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spin_unlock_irqrestore(&sem->lock, flags);
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}
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EXPORT_SYMBOL(down);
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@@ -77,10 +76,10 @@ int down_interruptible(struct semaphore *sem)
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int result = 0;
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spin_lock_irqsave(&sem->lock, flags);
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- if (likely(sem->count > 0))
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- sem->count--;
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- else
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+ if (unlikely(!sem->count))
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result = __down_interruptible(sem);
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+ if (!result)
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+ sem->count--;
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spin_unlock_irqrestore(&sem->lock, flags);
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return result;
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@@ -103,10 +102,10 @@ int down_killable(struct semaphore *sem)
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int result = 0;
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spin_lock_irqsave(&sem->lock, flags);
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- if (likely(sem->count > 0))
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- sem->count--;
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- else
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+ if (unlikely(!sem->count))
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result = __down_killable(sem);
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+ if (!result)
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+ sem->count--;
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spin_unlock_irqrestore(&sem->lock, flags);
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return result;
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@@ -157,10 +156,10 @@ int down_timeout(struct semaphore *sem, long jiffies)
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int result = 0;
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spin_lock_irqsave(&sem->lock, flags);
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- if (likely(sem->count > 0))
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- sem->count--;
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- else
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+ if (unlikely(!sem->count))
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result = __down_timeout(sem, jiffies);
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+ if (!result)
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+ sem->count--;
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spin_unlock_irqrestore(&sem->lock, flags);
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return result;
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@@ -179,9 +178,8 @@ void up(struct semaphore *sem)
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unsigned long flags;
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spin_lock_irqsave(&sem->lock, flags);
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- if (likely(list_empty(&sem->wait_list)))
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- sem->count++;
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- else
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+ sem->count++;
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+ if (unlikely(!list_empty(&sem->wait_list)))
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__up(sem);
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spin_unlock_irqrestore(&sem->lock, flags);
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}
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@@ -192,7 +190,6 @@ EXPORT_SYMBOL(up);
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struct semaphore_waiter {
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struct list_head list;
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struct task_struct *task;
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- int up;
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};
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/*
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@@ -205,33 +202,34 @@ static inline int __sched __down_common(struct semaphore *sem, long state,
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{
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struct task_struct *task = current;
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struct semaphore_waiter waiter;
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+ int ret = 0;
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- list_add_tail(&waiter.list, &sem->wait_list);
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waiter.task = task;
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- waiter.up = 0;
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+ list_add_tail(&waiter.list, &sem->wait_list);
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for (;;) {
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- if (state == TASK_INTERRUPTIBLE && signal_pending(task))
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- goto interrupted;
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- if (state == TASK_KILLABLE && fatal_signal_pending(task))
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- goto interrupted;
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- if (timeout <= 0)
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- goto timed_out;
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+ if (state == TASK_INTERRUPTIBLE && signal_pending(task)) {
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+ ret = -EINTR;
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+ break;
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+ }
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+ if (state == TASK_KILLABLE && fatal_signal_pending(task)) {
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+ ret = -EINTR;
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+ break;
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+ }
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+ if (timeout <= 0) {
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+ ret = -ETIME;
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+ break;
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+ }
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__set_task_state(task, state);
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spin_unlock_irq(&sem->lock);
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timeout = schedule_timeout(timeout);
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spin_lock_irq(&sem->lock);
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- if (waiter.up)
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- return 0;
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+ if (sem->count > 0)
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+ break;
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}
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- timed_out:
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- list_del(&waiter.list);
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- return -ETIME;
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-
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- interrupted:
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list_del(&waiter.list);
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- return -EINTR;
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+ return ret;
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}
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static noinline void __sched __down(struct semaphore *sem)
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@@ -258,7 +256,5 @@ static noinline void __sched __up(struct semaphore *sem)
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{
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struct semaphore_waiter *waiter = list_first_entry(&sem->wait_list,
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struct semaphore_waiter, list);
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- list_del(&waiter->list);
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- waiter->up = 1;
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wake_up_process(waiter->task);
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}
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