| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
| 15 | |
| 16 | /* |
| 17 | * Timeout for stopping processes |
| 18 | */ |
| 19 | #define TIMEOUT (6 * HZ) |
| 20 | |
| 21 | |
| 22 | static inline int freezeable(struct task_struct * p) |
| 23 | { |
| 24 | if ((p == current) || |
| 25 | (p->flags & PF_NOFREEZE) || |
| 26 | (p->exit_state == EXIT_ZOMBIE) || |
| 27 | (p->exit_state == EXIT_DEAD) || |
| 28 | (p->state == TASK_STOPPED) || |
| 29 | (p->state == TASK_TRACED)) |
| 30 | return 0; |
| 31 | return 1; |
| 32 | } |
| 33 | |
| 34 | /* Refrigerator is place where frozen processes are stored :-). */ |
| 35 | void refrigerator(unsigned long flag) |
| 36 | { |
| 37 | /* Hmm, should we be allowed to suspend when there are realtime |
| 38 | processes around? */ |
| 39 | long save; |
| 40 | save = current->state; |
| 41 | current->state = TASK_UNINTERRUPTIBLE; |
| 42 | pr_debug("%s entered refrigerator\n", current->comm); |
| 43 | printk("="); |
| 44 | current->flags &= ~PF_FREEZE; |
| 45 | |
| 46 | spin_lock_irq(¤t->sighand->siglock); |
| 47 | recalc_sigpending(); /* We sent fake signal, clean it up */ |
| 48 | spin_unlock_irq(¤t->sighand->siglock); |
| 49 | |
| 50 | current->flags |= PF_FROZEN; |
| 51 | while (current->flags & PF_FROZEN) |
| 52 | schedule(); |
| 53 | pr_debug("%s left refrigerator\n", current->comm); |
| 54 | current->state = save; |
| 55 | } |
| 56 | |
| 57 | /* 0 = success, else # of processes that we failed to stop */ |
| 58 | int freeze_processes(void) |
| 59 | { |
| 60 | int todo; |
| 61 | unsigned long start_time; |
| 62 | struct task_struct *g, *p; |
| 63 | |
| 64 | printk( "Stopping tasks: " ); |
| 65 | start_time = jiffies; |
| 66 | do { |
| 67 | todo = 0; |
| 68 | read_lock(&tasklist_lock); |
| 69 | do_each_thread(g, p) { |
| 70 | unsigned long flags; |
| 71 | if (!freezeable(p)) |
| 72 | continue; |
| 73 | if ((p->flags & PF_FROZEN) || |
| 74 | (p->state == TASK_TRACED) || |
| 75 | (p->state == TASK_STOPPED)) |
| 76 | continue; |
| 77 | |
| 78 | /* FIXME: smp problem here: we may not access other process' flags |
| 79 | without locking */ |
| 80 | p->flags |= PF_FREEZE; |
| 81 | spin_lock_irqsave(&p->sighand->siglock, flags); |
| 82 | signal_wake_up(p, 0); |
| 83 | spin_unlock_irqrestore(&p->sighand->siglock, flags); |
| 84 | todo++; |
| 85 | } while_each_thread(g, p); |
| 86 | read_unlock(&tasklist_lock); |
| 87 | yield(); /* Yield is okay here */ |
| 88 | if (time_after(jiffies, start_time + TIMEOUT)) { |
| 89 | printk( "\n" ); |
| 90 | printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo ); |
| 91 | return todo; |
| 92 | } |
| 93 | } while(todo); |
| 94 | |
| 95 | printk( "|\n" ); |
| 96 | BUG_ON(in_atomic()); |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | void thaw_processes(void) |
| 101 | { |
| 102 | struct task_struct *g, *p; |
| 103 | |
| 104 | printk( "Restarting tasks..." ); |
| 105 | read_lock(&tasklist_lock); |
| 106 | do_each_thread(g, p) { |
| 107 | if (!freezeable(p)) |
| 108 | continue; |
| 109 | if (p->flags & PF_FROZEN) { |
| 110 | p->flags &= ~PF_FROZEN; |
| 111 | wake_up_process(p); |
| 112 | } else |
| 113 | printk(KERN_INFO " Strange, %s not stopped\n", p->comm ); |
| 114 | } while_each_thread(g, p); |
| 115 | |
| 116 | read_unlock(&tasklist_lock); |
| 117 | schedule(); |
| 118 | printk( " done\n" ); |
| 119 | } |
| 120 | |
| 121 | EXPORT_SYMBOL(refrigerator); |