69 lines
1.5 KiB
C
69 lines
1.5 KiB
C
/*
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* Simple waitqueues without fancy flags and callbacks
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*
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* (C) 2011 Thomas Gleixner <tglx@linutronix.de>
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*
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* Based on kernel/wait.c
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*
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* For licencing details see kernel-base/COPYING
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*/
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/wait-simple.h>
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void __init_swait_head(struct swait_head *head, struct lock_class_key *key)
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{
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raw_spin_lock_init(&head->lock);
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lockdep_set_class(&head->lock, key);
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INIT_LIST_HEAD(&head->list);
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}
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EXPORT_SYMBOL(__init_swait_head);
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void swait_prepare(struct swait_head *head, struct swaiter *w, int state)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&head->lock, flags);
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w->task = current;
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if (list_empty(&w->node))
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__swait_enqueue(head, w);
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set_current_state(state);
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raw_spin_unlock_irqrestore(&head->lock, flags);
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}
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EXPORT_SYMBOL(swait_prepare);
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void swait_finish(struct swait_head *head, struct swaiter *w)
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{
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unsigned long flags;
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__set_current_state(TASK_RUNNING);
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if (w->task) {
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raw_spin_lock_irqsave(&head->lock, flags);
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__swait_dequeue(w);
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raw_spin_unlock_irqrestore(&head->lock, flags);
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}
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}
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EXPORT_SYMBOL(swait_finish);
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int __swait_wake(struct swait_head *head, unsigned int state)
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{
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struct swaiter *curr, *next;
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unsigned long flags;
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int woken = 0;
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raw_spin_lock_irqsave(&head->lock, flags);
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list_for_each_entry_safe(curr, next, &head->list, node) {
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if (wake_up_state(curr->task, state)) {
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__swait_dequeue(curr);
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curr->task = NULL;
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woken++;
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}
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}
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raw_spin_unlock_irqrestore(&head->lock, flags);
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return woken;
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}
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EXPORT_SYMBOL(__swait_wake);
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