[linux-2.6-block.git] / kernel / sched / swait.c

#include <linux/sched.h>
#include <linux/swait.h>

void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
			     struct lock_class_key *key)
{
	raw_spin_lock_init(&q->lock);
	lockdep_set_class_and_name(&q->lock, key, name);
	INIT_LIST_HEAD(&q->task_list);
}
EXPORT_SYMBOL(__init_swait_queue_head);

/*
 * The thing about the wake_up_state() return value; I think we can ignore it.
 *
 * If for some reason it would return 0, that means the previously waiting
 * task is already running, so it will observe condition true (or has already).
 */
void swake_up_locked(struct swait_queue_head *q)
{
	struct swait_queue *curr;

	if (list_empty(&q->task_list))
		return;

	curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
	wake_up_process(curr->task);
	list_del_init(&curr->task_list);
}
EXPORT_SYMBOL(swake_up_locked);

void swake_up(struct swait_queue_head *q)
{
	unsigned long flags;

	if (!swait_active(q))
		return;

	raw_spin_lock_irqsave(&q->lock, flags);
	swake_up_locked(q);
	raw_spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(swake_up);

/*
 * Does not allow usage from IRQ disabled, since we must be able to
 * release IRQs to guarantee bounded hold time.
 */
void swake_up_all(struct swait_queue_head *q)
{
	struct swait_queue *curr;
	LIST_HEAD(tmp);

	if (!swait_active(q))
		return;

	raw_spin_lock_irq(&q->lock);
	list_splice_init(&q->task_list, &tmp);
	while (!list_empty(&tmp)) {
		curr = list_first_entry(&tmp, typeof(*curr), task_list);

		wake_up_state(curr->task, TASK_NORMAL);
		list_del_init(&curr->task_list);

		if (list_empty(&tmp))
			break;

		raw_spin_unlock_irq(&q->lock);
		raw_spin_lock_irq(&q->lock);
	}
	raw_spin_unlock_irq(&q->lock);
}
EXPORT_SYMBOL(swake_up_all);

void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
	wait->task = current;
	if (list_empty(&wait->task_list))
		list_add(&wait->task_list, &q->task_list);
}

void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&q->lock, flags);
	__prepare_to_swait(q, wait);
	set_current_state(state);
	raw_spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(prepare_to_swait);

long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state)
{
	if (signal_pending_state(state, current))
		return -ERESTARTSYS;

	prepare_to_swait(q, wait, state);

	return 0;
}
EXPORT_SYMBOL(prepare_to_swait_event);

void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
	__set_current_state(TASK_RUNNING);
	if (!list_empty(&wait->task_list))
		list_del_init(&wait->task_list);
}

void finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
{
	unsigned long flags;

	__set_current_state(TASK_RUNNING);

	if (!list_empty_careful(&wait->task_list)) {
		raw_spin_lock_irqsave(&q->lock, flags);
		list_del_init(&wait->task_list);
		raw_spin_unlock_irqrestore(&q->lock, flags);
	}
}
EXPORT_SYMBOL(finish_swait);
Commit	Line	Data
13b35686 PZI	1	#include <linux/sched.h>
	2	#include <linux/swait.h>
	3
	4	void __init_swait_queue_head(struct swait_queue_head q, const char name,
	5	struct lock_class_key *key)
	6	{
	7	raw_spin_lock_init(&q->lock);
	8	lockdep_set_class_and_name(&q->lock, key, name);
	9	INIT_LIST_HEAD(&q->task_list);
	10	}
	11	EXPORT_SYMBOL(__init_swait_queue_head);
	12
	13	/*
	14	* The thing about the wake_up_state() return value; I think we can ignore it.
	15	*
	16	* If for some reason it would return 0, that means the previously waiting
	17	* task is already running, so it will observe condition true (or has already).
	18	*/
	19	void swake_up_locked(struct swait_queue_head *q)
	20	{
	21	struct swait_queue *curr;
	22
	23	if (list_empty(&q->task_list))
	24	return;
	25
	26	curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
	27	wake_up_process(curr->task);
	28	list_del_init(&curr->task_list);
	29	}
	30	EXPORT_SYMBOL(swake_up_locked);
	31
	32	void swake_up(struct swait_queue_head *q)
	33	{
	34	unsigned long flags;
	35
	36	if (!swait_active(q))
	37	return;
	38
	39	raw_spin_lock_irqsave(&q->lock, flags);
	40	swake_up_locked(q);
	41	raw_spin_unlock_irqrestore(&q->lock, flags);
	42	}
	43	EXPORT_SYMBOL(swake_up);
	44
	45	/*
	46	* Does not allow usage from IRQ disabled, since we must be able to
	47	* release IRQs to guarantee bounded hold time.
	48	*/
	49	void swake_up_all(struct swait_queue_head *q)
	50	{
	51	struct swait_queue *curr;
	52	LIST_HEAD(tmp);
	53
	54	if (!swait_active(q))
	55	return;
	56
	57	raw_spin_lock_irq(&q->lock);
	58	list_splice_init(&q->task_list, &tmp);
	59	while (!list_empty(&tmp)) {
	60	curr = list_first_entry(&tmp, typeof(*curr), task_list);
	61
	62	wake_up_state(curr->task, TASK_NORMAL);
	63	list_del_init(&curr->task_list);
	64
65	if (list_empty(&tmp))
66	break;
67
68	raw_spin_unlock_irq(&q->lock);
69	raw_spin_lock_irq(&q->lock);
70	}
71	raw_spin_unlock_irq(&q->lock);
72	}
73	EXPORT_SYMBOL(swake_up_all);
74
75	void __prepare_to_swait(struct swait_queue_head q, struct swait_queue wait)
76	{
77	wait->task = current;
78	if (list_empty(&wait->task_list))
79	list_add(&wait->task_list, &q->task_list);
80	}
81
82	void prepare_to_swait(struct swait_queue_head q, struct swait_queue wait, int state)
83	{
84	unsigned long flags;
85
86	raw_spin_lock_irqsave(&q->lock, flags);
87	__prepare_to_swait(q, wait);
88	set_current_state(state);
89	raw_spin_unlock_irqrestore(&q->lock, flags);
90	}
91	EXPORT_SYMBOL(prepare_to_swait);
92
93	long prepare_to_swait_event(struct swait_queue_head q, struct swait_queue wait, int state)
94	{
95	if (signal_pending_state(state, current))
96	return -ERESTARTSYS;
97
98	prepare_to_swait(q, wait, state);
99
100	return 0;
101	}
102	EXPORT_SYMBOL(prepare_to_swait_event);
103
104	void __finish_swait(struct swait_queue_head q, struct swait_queue wait)
105	{
106	__set_current_state(TASK_RUNNING);
107	if (!list_empty(&wait->task_list))
108	list_del_init(&wait->task_list);
109	}
110
111	void finish_swait(struct swait_queue_head q, struct swait_queue wait)
112	{
113	unsigned long flags;
114
115	__set_current_state(TASK_RUNNING);
116
117	if (!list_empty_careful(&wait->task_list)) {
118	raw_spin_lock_irqsave(&q->lock, flags);
119	list_del_init(&wait->task_list);
120	raw_spin_unlock_irqrestore(&q->lock, flags);
121	}
122	}
123	EXPORT_SYMBOL(finish_swait);