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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>
#include <linux/syscalls.h>
#include <linux/freezer.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);
frozen_process(current);
spin_lock_irq(¤t->sighand->siglock);
recalc_sigpending(); /* We sent fake signal, clean it up */
spin_unlock_irq(¤t->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);
}
}
static void cancel_freezing(struct task_struct *p)
{
unsigned long flags;
if (freezing(p)) {
pr_debug(" clean up: %s\n", p->comm);
do_not_freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
recalc_sigpending_tsk(p);
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;
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->state == TASK_TRACED &&
(frozen(p->parent) ||
p->parent->state == TASK_STOPPED)) {
cancel_freezing(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);
cancel_freezing(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
return todo;
}
printk("done.\n");
BUG_ON(in_atomic());
return 0;
}
void thaw_some_processes(int all)
{
struct task_struct *g, *p;
int pass = 0; /* Pass 0 = Kernel space, 1 = Userspace */
printk("Restarting tasks... ");
read_lock(&tasklist_lock);
do {
do_each_thread(g, p) {
/*
* is_user = 0 if kernel thread or borrowed mm,
* 1 otherwise.
*/
int is_user = !!(p->mm && !(p->flags & PF_BORROWED_MM));
if (!freezeable(p) || (is_user != pass))
continue;
if (!thaw_process(p))
printk(KERN_INFO
"Strange, %s not stopped\n", p->comm);
} while_each_thread(g, p);
pass++;
} while (pass < 2 && all);
read_unlock(&tasklist_lock);
schedule();
printk("done.\n");
}
EXPORT_SYMBOL(refrigerator);
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