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