[net-next-2.6.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>
#include <linux/syscalls.h>

/* 
 * Timeout for stopping processes
 */
#define TIMEOUT	(20 * 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))
		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;
}

static inline void freeze_process(struct task_struct *p)
{
	unsigned long flags;

	if (!freezing(p)) {
		freeze(p);
		spin_lock_irqsave(&p->sighand->siglock, flags);
		signal_wake_up(p, 0);
		spin_unlock_irqrestore(&p->sighand->siglock, flags);
	}
}

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

	printk( "Stopping tasks: " );
	start_time = jiffies;
	user_frozen = 0;
	do {
		nr_user = todo = 0;
		read_lock(&tasklist_lock);
		do_each_thread(g, p) {
			if (!freezeable(p))
				continue;
			if (frozen(p))
				continue;
			if (p->mm && !(p->flags & PF_BORROWED_MM)) {
				/* The task is a user-space one.
				 * Freeze it unless there's a vfork completion
				 * pending
				 */
				if (!p->vfork_done)
					freeze_process(p);
				nr_user++;
			} else {
				/* Freeze only if the user space is frozen */
				if (user_frozen)
					freeze_process(p);
				todo++;
			}
		} while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		todo += nr_user;
		if (!user_frozen && !nr_user) {
			sys_sync();
			start_time = jiffies;
		}
		user_frozen = !nr_user;
		yield();			/* Yield is okay here */
		if (todo && time_after(jiffies, start_time + TIMEOUT))
			break;
	} while(todo);

	/* This does not unfreeze processes that are already frozen
	 * (we have slightly ugly calling convention in that respect,
	 * and caller must call thaw_processes() if something fails),
	 * but it cleans up leftover PF_FREEZE requests.
	 */
	if (todo) {
		printk( "\n" );
		printk(KERN_ERR " stopping tasks timed out "
			"after %d seconds (%d tasks remaining):\n",
			TIMEOUT / HZ, todo);
		read_lock(&tasklist_lock);
		do_each_thread(g, p) {
			if (freezeable(p) && !frozen(p))
				printk(KERN_ERR "  %s\n", p->comm);
			if (freezing(p)) {
				pr_debug("  clean up: %s\n", p->comm);
				p->flags &= ~PF_FREEZE;
				spin_lock_irqsave(&p->sighand->siglock, flags);
				recalc_sigpending_tsk(p);
				spin_unlock_irqrestore(&p->sighand->siglock, flags);
			}
		} while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		return 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>
02aaeb9b	15	#include <linux/syscalls.h>
1da177e4 LT	16
	17	/*
	18	* Timeout for stopping processes
	19	*/
02aaeb9b	20	#define TIMEOUT (20 * HZ)
1da177e4 LT	21
	22
	23	static inline int freezeable(struct task_struct * p)
	24	{
	25	if ((p == current) \|\|
	26	(p->flags & PF_NOFREEZE) \|\|
	27	(p->exit_state == EXIT_ZOMBIE) \|\|
	28	(p->exit_state == EXIT_DEAD) \|\|
85b6bce3	29	(p->state == TASK_STOPPED))
1da177e4 LT	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
02aaeb9b RW	57	static inline void freeze_process(struct task_struct *p)
	58	{
	59	unsigned long flags;
	60
	61	if (!freezing(p)) {
	62	freeze(p);
	63	spin_lock_irqsave(&p->sighand->siglock, flags);
	64	signal_wake_up(p, 0);
	65	spin_unlock_irqrestore(&p->sighand->siglock, flags);
	66	}
	67	}
	68
1da177e4 LT	69	/* 0 = success, else # of processes that we failed to stop */
	70	int freeze_processes(void)
	71	{
02aaeb9b	72	int todo, nr_user, user_frozen;
3e1d1d28	73	unsigned long start_time;
1da177e4	74	struct task_struct g, p;
1322ad41	75	unsigned long flags;
3e1d1d28	76
1da177e4 LT	77	printk( "Stopping tasks: " );
1da177e4 LT	78	start_time = jiffies;
02aaeb9b	79	user_frozen = 0;
1da177e4	80	do {
02aaeb9b	81	nr_user = todo = 0;
1da177e4 LT	82	read_lock(&tasklist_lock);
1da177e4 LT	83	do_each_thread(g, p) {
1da177e4 LT	84	if (!freezeable(p))
1da177e4 LT	85	continue;
1322ad41	86	if (frozen(p))
1da177e4	87	continue;
02aaeb9b RW	88	if (p->mm && !(p->flags & PF_BORROWED_MM)) {
	89	/* The task is a user-space one.
	90	* Freeze it unless there's a vfork completion
	91	* pending
	92	*/
	93	if (!p->vfork_done)
	94	freeze_process(p);
	95	nr_user++;
	96	} else {
	97	/* Freeze only if the user space is frozen */
	98	if (user_frozen)
	99	freeze_process(p);
	100	todo++;
	101	}
1da177e4 LT	102	} while_each_thread(g, p);
1da177e4 LT	103	read_unlock(&tasklist_lock);
02aaeb9b RW	104	todo += nr_user;
	105	if (!user_frozen && !nr_user) {
	106	sys_sync();
	107	start_time = jiffies;
	108	}
	109	user_frozen = !nr_user;
1da177e4	110	yield(); /* Yield is okay here */
02aaeb9b	111	if (todo && time_after(jiffies, start_time + TIMEOUT))
6161b2ce	112	break;
1da177e4	113	} while(todo);
3e1d1d28	114
6161b2ce PM	115	/* This does not unfreeze processes that are already frozen
	116	* (we have slightly ugly calling convention in that respect,
	117	* and caller must call thaw_processes() if something fails),
	118	* but it cleans up leftover PF_FREEZE requests.
	119	*/
	120	if (todo) {
02aaeb9b RW	121	printk( "\n" );
	122	printk(KERN_ERR " stopping tasks timed out "
	123	"after %d seconds (%d tasks remaining):\n",
	124	TIMEOUT / HZ, todo);
6161b2ce	125	read_lock(&tasklist_lock);
02aaeb9b RW	126	do_each_thread(g, p) {
	127	if (freezeable(p) && !frozen(p))
	128	printk(KERN_ERR " %s\n", p->comm);
6161b2ce PM	129	if (freezing(p)) {
	130	pr_debug(" clean up: %s\n", p->comm);
	131	p->flags &= ~PF_FREEZE;
	132	spin_lock_irqsave(&p->sighand->siglock, flags);
	133	recalc_sigpending_tsk(p);
	134	spin_unlock_irqrestore(&p->sighand->siglock, flags);
	135	}
02aaeb9b	136	} while_each_thread(g, p);
6161b2ce PM	137	read_unlock(&tasklist_lock);
	138	return todo;
	139	}
	140
1da177e4 LT	141	printk( "\|\n" );
	142	BUG_ON(in_atomic());
	143	return 0;
	144	}
	145
	146	void thaw_processes(void)
	147	{
	148	struct task_struct g, p;
	149
	150	printk( "Restarting tasks..." );
	151	read_lock(&tasklist_lock);
	152	do_each_thread(g, p) {
	153	if (!freezeable(p))
	154	continue;
3e1d1d28	155	if (!thaw_process(p))
1da177e4 LT	156	printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
	157	} while_each_thread(g, p);
	158
	159	read_unlock(&tasklist_lock);
	160	schedule();
	161	printk( " done\n" );
	162	}
	163
	164	EXPORT_SYMBOL(refrigerator);