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 pr_debug("%s entered refrigerator\n", current->comm); 42 printk("="); 43 44 frozen_process(current); 45 spin_lock_irq(¤t->sighand->siglock); 46 recalc_sigpending(); /* We sent fake signal, clean it up */ 47 spin_unlock_irq(¤t->sighand->siglock); 48 49 while (frozen(current)) { 50 current->state = TASK_UNINTERRUPTIBLE; 51 schedule(); 52 } 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 unsigned long flags; 64 65 printk( "Stopping tasks: " ); 66 start_time = jiffies; 67 do { 68 todo = 0; 69 read_lock(&tasklist_lock); 70 do_each_thread(g, p) { 71 if (!freezeable(p)) 72 continue; 73 if (frozen(p)) 74 continue; 75 76 freeze(p); 77 spin_lock_irqsave(&p->sighand->siglock, flags); 78 signal_wake_up(p, 0); 79 spin_unlock_irqrestore(&p->sighand->siglock, flags); 80 todo++; 81 } while_each_thread(g, p); 82 read_unlock(&tasklist_lock); 83 yield(); /* Yield is okay here */ 84 if (todo && time_after(jiffies, start_time + TIMEOUT)) { 85 printk( "\n" ); 86 printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo ); 87 break; 88 } 89 } while(todo); 90 91 /* This does not unfreeze processes that are already frozen 92 * (we have slightly ugly calling convention in that respect, 93 * and caller must call thaw_processes() if something fails), 94 * but it cleans up leftover PF_FREEZE requests. 95 */ 96 if (todo) { 97 read_lock(&tasklist_lock); 98 do_each_thread(g, p) 99 if (freezing(p)) { 100 pr_debug(" clean up: %s\n", p->comm); 101 p->flags &= ~PF_FREEZE; 102 spin_lock_irqsave(&p->sighand->siglock, flags); 103 recalc_sigpending_tsk(p); 104 spin_unlock_irqrestore(&p->sighand->siglock, flags); 105 } 106 while_each_thread(g, p); 107 read_unlock(&tasklist_lock); 108 return todo; 109 } 110 111 printk( "|\n" ); 112 BUG_ON(in_atomic()); 113 return 0; 114 } 115 116 void thaw_processes(void) 117 { 118 struct task_struct *g, *p; 119 120 printk( "Restarting tasks..." ); 121 read_lock(&tasklist_lock); 122 do_each_thread(g, p) { 123 if (!freezeable(p)) 124 continue; 125 if (!thaw_process(p)) 126 printk(KERN_INFO " Strange, %s not stopped\n", p->comm ); 127 } while_each_thread(g, p); 128 129 read_unlock(&tasklist_lock); 130 schedule(); 131 printk( " done\n" ); 132 } 133 134 EXPORT_SYMBOL(refrigerator); 135