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/*
* 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(unsigned long flag)
{
/* Hmm, should we be allowed to suspend when there are realtime
processes around? */
long save;
save = current->state;
current->state = TASK_UNINTERRUPTIBLE;
pr_debug("%s entered refrigerator\n", current->comm);
printk("=");
current->flags &= ~PF_FREEZE;
spin_lock_irq(¤t->sighand->siglock);
recalc_sigpending(); /* We sent fake signal, clean it up */
spin_unlock_irq(¤t->sighand->siglock);
current->flags |= PF_FROZEN;
while (current->flags & PF_FROZEN)
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;
printk( "Stopping tasks: " );
start_time = jiffies;
do {
todo = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
unsigned long flags;
if (!freezeable(p))
continue;
if ((p->flags & PF_FROZEN) ||
(p->state == TASK_TRACED) ||
(p->state == TASK_STOPPED))
continue;
/* FIXME: smp problem here: we may not access other process' flags
without locking */
p->flags |= PF_FREEZE;
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 (p->flags & PF_FROZEN) {
p->flags &= ~PF_FROZEN;
wake_up_process(p);
} else
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);
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