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