188 lines
4.3 KiB
C
188 lines
4.3 KiB
C
/*
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* drivers/power/process.c - Functions for starting/stopping processes on
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* suspend transitions.
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*
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* Originally from swsusp.
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*/
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#undef DEBUG
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#include <linux/smp_lock.h>
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#include <linux/interrupt.h>
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#include <linux/suspend.h>
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#include <linux/module.h>
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#include <linux/syscalls.h>
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#include <linux/freezer.h>
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/*
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* Timeout for stopping processes
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*/
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#define TIMEOUT (20 * HZ)
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static inline int freezeable(struct task_struct * p)
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{
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if ((p == current) ||
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(p->flags & PF_NOFREEZE) ||
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(p->exit_state == EXIT_ZOMBIE) ||
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(p->exit_state == EXIT_DEAD) ||
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(p->state == TASK_STOPPED))
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return 0;
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return 1;
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}
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/* Refrigerator is place where frozen processes are stored :-). */
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void refrigerator(void)
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{
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/* Hmm, should we be allowed to suspend when there are realtime
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processes around? */
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long save;
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save = current->state;
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pr_debug("%s entered refrigerator\n", current->comm);
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frozen_process(current);
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spin_lock_irq(¤t->sighand->siglock);
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recalc_sigpending(); /* We sent fake signal, clean it up */
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spin_unlock_irq(¤t->sighand->siglock);
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while (frozen(current)) {
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current->state = TASK_UNINTERRUPTIBLE;
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schedule();
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}
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pr_debug("%s left refrigerator\n", current->comm);
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current->state = save;
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}
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static inline void freeze_process(struct task_struct *p)
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{
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unsigned long flags;
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if (!freezing(p)) {
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freeze(p);
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spin_lock_irqsave(&p->sighand->siglock, flags);
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signal_wake_up(p, 0);
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spin_unlock_irqrestore(&p->sighand->siglock, flags);
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}
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}
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static void cancel_freezing(struct task_struct *p)
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{
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unsigned long flags;
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if (freezing(p)) {
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pr_debug(" clean up: %s\n", p->comm);
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do_not_freeze(p);
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spin_lock_irqsave(&p->sighand->siglock, flags);
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recalc_sigpending_tsk(p);
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spin_unlock_irqrestore(&p->sighand->siglock, flags);
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}
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}
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/* 0 = success, else # of processes that we failed to stop */
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int freeze_processes(void)
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{
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int todo, nr_user, user_frozen;
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unsigned long start_time;
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struct task_struct *g, *p;
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printk("Stopping tasks... ");
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start_time = jiffies;
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user_frozen = 0;
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do {
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nr_user = todo = 0;
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read_lock(&tasklist_lock);
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do_each_thread(g, p) {
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if (!freezeable(p))
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continue;
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if (frozen(p))
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continue;
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if (p->state == TASK_TRACED &&
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(frozen(p->parent) ||
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p->parent->state == TASK_STOPPED)) {
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cancel_freezing(p);
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continue;
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}
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if (p->mm && !(p->flags & PF_BORROWED_MM)) {
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/* The task is a user-space one.
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* Freeze it unless there's a vfork completion
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* pending
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*/
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if (!p->vfork_done)
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freeze_process(p);
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nr_user++;
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} else {
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/* Freeze only if the user space is frozen */
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if (user_frozen)
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freeze_process(p);
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todo++;
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}
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} while_each_thread(g, p);
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read_unlock(&tasklist_lock);
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todo += nr_user;
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if (!user_frozen && !nr_user) {
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sys_sync();
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start_time = jiffies;
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}
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user_frozen = !nr_user;
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yield(); /* Yield is okay here */
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if (todo && time_after(jiffies, start_time + TIMEOUT))
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break;
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} while(todo);
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/* This does not unfreeze processes that are already frozen
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* (we have slightly ugly calling convention in that respect,
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* and caller must call thaw_processes() if something fails),
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* but it cleans up leftover PF_FREEZE requests.
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*/
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if (todo) {
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printk("\n");
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printk(KERN_ERR "Stopping tasks timed out "
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"after %d seconds (%d tasks remaining):\n",
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TIMEOUT / HZ, todo);
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read_lock(&tasklist_lock);
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do_each_thread(g, p) {
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if (freezeable(p) && !frozen(p))
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printk(KERN_ERR " %s\n", p->comm);
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cancel_freezing(p);
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} while_each_thread(g, p);
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read_unlock(&tasklist_lock);
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return todo;
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}
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printk("done.\n");
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BUG_ON(in_atomic());
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return 0;
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}
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void thaw_some_processes(int all)
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{
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struct task_struct *g, *p;
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int pass = 0; /* Pass 0 = Kernel space, 1 = Userspace */
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printk("Restarting tasks... ");
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read_lock(&tasklist_lock);
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do {
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do_each_thread(g, p) {
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/*
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* is_user = 0 if kernel thread or borrowed mm,
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* 1 otherwise.
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*/
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int is_user = !!(p->mm && !(p->flags & PF_BORROWED_MM));
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if (!freezeable(p) || (is_user != pass))
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continue;
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if (!thaw_process(p))
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printk(KERN_INFO
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"Strange, %s not stopped\n", p->comm);
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} while_each_thread(g, p);
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pass++;
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} while (pass < 2 && all);
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read_unlock(&tasklist_lock);
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schedule();
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printk("done.\n");
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}
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EXPORT_SYMBOL(refrigerator);
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