[mirror_ubuntu-artful-kernel.git] / kernel / power / process.c

/*
 * drivers/power/process.c - Functions for starting/stopping processes on 
 *                           suspend transitions.
 *
 * Originally from swsusp.
 */


#undef DEBUG

#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/module.h>

/* 
 * Timeout for stopping processes
 */
#define TIMEOUT	(6 * HZ)


static inline int freezeable(struct task_struct * p)
{
	if ((p == current) || 
	    (p->flags & PF_NOFREEZE) ||
	    (p->exit_state == EXIT_ZOMBIE) ||
	    (p->exit_state == EXIT_DEAD) ||
	    (p->state == TASK_STOPPED) ||
	    (p->state == TASK_TRACED))
		return 0;
	return 1;
}

/* Refrigerator is place where frozen processes are stored :-). */
void refrigerator(void)
{
	/* Hmm, should we be allowed to suspend when there are realtime
	   processes around? */
	long save;
	save = current->state;
	pr_debug("%s entered refrigerator\n", current->comm);
	printk("=");

	frozen_process(current);
	spin_lock_irq(&current->sighand->siglock);
	recalc_sigpending(); /* We sent fake signal, clean it up */
	spin_unlock_irq(&current->sighand->siglock);

	while (frozen(current)) {
		current->state = TASK_UNINTERRUPTIBLE;
		schedule();
	}
	pr_debug("%s left refrigerator\n", current->comm);
	current->state = save;
}

/* 0 = success, else # of processes that we failed to stop */
int freeze_processes(void)
{
	int todo;
	unsigned long start_time;
	struct task_struct *g, *p;
	unsigned long flags;

	printk( "Stopping tasks: " );
	start_time = jiffies;
	do {
		todo = 0;
		read_lock(&tasklist_lock);
		do_each_thread(g, p) {
			if (!freezeable(p))
				continue;
			if (frozen(p))
				continue;

			freeze(p);
			spin_lock_irqsave(&p->sighand->siglock, flags);
			signal_wake_up(p, 0);
			spin_unlock_irqrestore(&p->sighand->siglock, flags);
			todo++;
		} while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		yield();			/* Yield is okay here */
		if (time_after(jiffies, start_time + TIMEOUT)) {
			printk( "\n" );
			printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
			return todo;
		}
	} while(todo);

	printk( "|\n" );
	BUG_ON(in_atomic());
	return 0;
}

void thaw_processes(void)
{
	struct task_struct *g, *p;

	printk( "Restarting tasks..." );
	read_lock(&tasklist_lock);
	do_each_thread(g, p) {
		if (!freezeable(p))
			continue;
		if (!thaw_process(p))
			printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
	} while_each_thread(g, p);

	read_unlock(&tasklist_lock);
	schedule();
	printk( " done\n" );
}

EXPORT_SYMBOL(refrigerator);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/power/process.c - Functions for starting/stopping processes on
	3	* suspend transitions.
	4	*
	5	* Originally from swsusp.
	6	*/
	7
	8
	9	#undef DEBUG
	10
	11	#include <linux/smp_lock.h>
	12	#include <linux/interrupt.h>
	13	#include <linux/suspend.h>
	14	#include <linux/module.h>
	15
	16	/*
	17	* Timeout for stopping processes
	18	*/
	19	#define TIMEOUT (6 * HZ)
	20
	21
	22	static inline int freezeable(struct task_struct * p)
	23	{
	24	if ((p == current) \|\|
	25	(p->flags & PF_NOFREEZE) \|\|
	26	(p->exit_state == EXIT_ZOMBIE) \|\|
	27	(p->exit_state == EXIT_DEAD) \|\|
	28	(p->state == TASK_STOPPED) \|\|
	29	(p->state == TASK_TRACED))
	30	return 0;
	31	return 1;
	32	}
	33
	34	/* Refrigerator is place where frozen processes are stored :-). */
3e1d1d28	35	void refrigerator(void)
1da177e4 LT	36	{
	37	/* Hmm, should we be allowed to suspend when there are realtime
	38	processes around? */
	39	long save;
	40	save = current->state;
1da177e4 LT	41	pr_debug("%s entered refrigerator\n", current->comm);
1da177e4 LT	42	printk("=");
1da177e4	43
3e1d1d28	44	frozen_process(current);
1da177e4 LT	45	spin_lock_irq(&current->sighand->siglock);
	46	recalc_sigpending(); /* We sent fake signal, clean it up */
	47	spin_unlock_irq(&current->sighand->siglock);
	48
2a23b5d1 PM	49	while (frozen(current)) {
2a23b5d1 PM	50	current->state = TASK_UNINTERRUPTIBLE;
1da177e4	51	schedule();
2a23b5d1	52	}
1da177e4 LT	53	pr_debug("%s left refrigerator\n", current->comm);
	54	current->state = save;
	55	}
	56
	57	/* 0 = success, else # of processes that we failed to stop */
	58	int freeze_processes(void)
	59	{
3e1d1d28 CL	60	int todo;
3e1d1d28 CL	61	unsigned long start_time;
1da177e4	62	struct task_struct g, p;
1322ad41	63	unsigned long flags;
3e1d1d28	64
1da177e4 LT	65	printk( "Stopping tasks: " );
	66	start_time = jiffies;
	67	do {
	68	todo = 0;
	69	read_lock(&tasklist_lock);
	70	do_each_thread(g, p) {
1da177e4 LT	71	if (!freezeable(p))
1da177e4 LT	72	continue;
1322ad41	73	if (frozen(p))
1da177e4 LT	74	continue;
1da177e4 LT	75
3e1d1d28	76	freeze(p);
1da177e4 LT	77	spin_lock_irqsave(&p->sighand->siglock, flags);
	78	signal_wake_up(p, 0);
	79	spin_unlock_irqrestore(&p->sighand->siglock, flags);
	80	todo++;
	81	} while_each_thread(g, p);
	82	read_unlock(&tasklist_lock);
	83	yield(); /* Yield is okay here */
	84	if (time_after(jiffies, start_time + TIMEOUT)) {
	85	printk( "\n" );
	86	printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
	87	return todo;
	88	}
	89	} while(todo);
3e1d1d28	90
1da177e4 LT	91	printk( "\|\n" );
	92	BUG_ON(in_atomic());
	93	return 0;
	94	}
	95
	96	void thaw_processes(void)
	97	{
	98	struct task_struct g, p;
	99
	100	printk( "Restarting tasks..." );
	101	read_lock(&tasklist_lock);
	102	do_each_thread(g, p) {
	103	if (!freezeable(p))
	104	continue;
3e1d1d28	105	if (!thaw_process(p))
1da177e4 LT	106	printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
	107	} while_each_thread(g, p);
	108
	109	read_unlock(&tasklist_lock);
	110	schedule();
	111	printk( " done\n" );
	112	}
	113
	114	EXPORT_SYMBOL(refrigerator);