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(void) 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 45 frozen_process(current); 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 while (frozen(current)) 51 schedule(); 52 pr_debug("%s left refrigerator\n", current->comm); 53 current->state = save; 54 } 55 56 /* 0 = success, else # of processes that we failed to stop */ 57 int freeze_processes(void) 58 { 59 int todo; 60 unsigned long start_time; 61 struct task_struct *g, *p; 62 63 printk( "Stopping tasks: " ); 64 start_time = jiffies; 65 do { 66 todo = 0; 67 read_lock(&tasklist_lock); 68 do_each_thread(g, p) { 69 unsigned long flags; 70 if (!freezeable(p)) 71 continue; 72 if ((frozen(p)) || 73 (p->state == TASK_TRACED) || 74 (p->state == TASK_STOPPED)) 75 continue; 76 77 freeze(p); 78 spin_lock_irqsave(&p->sighand->siglock, flags); 79 signal_wake_up(p, 0); 80 spin_unlock_irqrestore(&p->sighand->siglock, flags); 81 todo++; 82 } while_each_thread(g, p); 83 read_unlock(&tasklist_lock); 84 yield(); /* Yield is okay here */ 85 if (time_after(jiffies, start_time + TIMEOUT)) { 86 printk( "\n" ); 87 printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo ); 88 return todo; 89 } 90 } while(todo); 91 92 printk( "|\n" ); 93 BUG_ON(in_atomic()); 94 return 0; 95 } 96 97 void thaw_processes(void) 98 { 99 struct task_struct *g, *p; 100 101 printk( "Restarting tasks..." ); 102 read_lock(&tasklist_lock); 103 do_each_thread(g, p) { 104 if (!freezeable(p)) 105 continue; 106 if (!thaw_process(p)) 107 printk(KERN_INFO " Strange, %s not stopped\n", p->comm ); 108 } while_each_thread(g, p); 109 110 read_unlock(&tasklist_lock); 111 schedule(); 112 printk( " done\n" ); 113 } 114 115 EXPORT_SYMBOL(refrigerator); 116