(2006-08-06) rescue-bootcd

extra/linux-2.6.10/kernel/power/process.c

@@ -0,0 +1,121 @@
+/*
+ * drivers/power/process.c - Functions for starting/stopping processes on 
+ *                           suspend transitions.
+ *
+ * Originally from swsusp.
+ */
+
+
+#undef DEBUG
+
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/suspend.h>
+#include <linux/module.h>
+
+/* 
+ * Timeout for stopping processes
+ */
+#define TIMEOUT	(6 * HZ)
+
+
+static inline int freezeable(struct task_struct * p)
+{
+	if ((p == current) || 
+	    (p->flags & PF_NOFREEZE) ||
+	    (p->exit_state == EXIT_ZOMBIE) ||
+	    (p->exit_state == EXIT_DEAD) ||
+	    (p->state == TASK_STOPPED) ||
+	    (p->state == TASK_TRACED))
+		return 0;
+	return 1;
+}
+
+/* Refrigerator is place where frozen processes are stored :-). */
+void refrigerator(unsigned long flag)
+{
+	/* Hmm, should we be allowed to suspend when there are realtime
+	   processes around? */
+	long save;
+	save = current->state;
+	current->state = TASK_UNINTERRUPTIBLE;
+	pr_debug("%s entered refrigerator\n", current->comm);
+	printk("=");
+	current->flags &= ~PF_FREEZE;
+
+	spin_lock_irq(&current->sighand->siglock);
+	recalc_sigpending(); /* We sent fake signal, clean it up */
+	spin_unlock_irq(&current->sighand->siglock);
+
+	current->flags |= PF_FROZEN;
+	while (current->flags & PF_FROZEN)
+		schedule();
+	pr_debug("%s left refrigerator\n", current->comm);
+	current->state = save;
+}
+
+/* 0 = success, else # of processes that we failed to stop */
+int freeze_processes(void)
+{
+       int todo;
+       unsigned long start_time;
+	struct task_struct *g, *p;
+	
+	printk( "Stopping tasks: " );
+	start_time = jiffies;
+	do {
+		todo = 0;
+		read_lock(&tasklist_lock);
+		do_each_thread(g, p) {
+			unsigned long flags;
+			if (!freezeable(p))
+				continue;
+			if ((p->flags & PF_FROZEN) ||
+			    (p->state == TASK_TRACED) ||
+			    (p->state == TASK_STOPPED))
+				continue;
+
+			/* FIXME: smp problem here: we may not access other process' flags
+			   without locking */
+			p->flags |= PF_FREEZE;
+			spin_lock_irqsave(&p->sighand->siglock, flags);
+			signal_wake_up(p, 0);
+			spin_unlock_irqrestore(&p->sighand->siglock, flags);
+			todo++;
+		} while_each_thread(g, p);
+		read_unlock(&tasklist_lock);
+		yield();			/* Yield is okay here */
+		if (time_after(jiffies, start_time + TIMEOUT)) {
+			printk( "\n" );
+			printk(KERN_ERR " stopping tasks failed (%d tasks remaining)\n", todo );
+			return todo;
+		}
+	} while(todo);
+	
+	printk( "|\n" );
+	BUG_ON(in_atomic());
+	return 0;
+}
+
+void thaw_processes(void)
+{
+	struct task_struct *g, *p;
+
+	printk( "Restarting tasks..." );
+	read_lock(&tasklist_lock);
+	do_each_thread(g, p) {
+		if (!freezeable(p))
+			continue;
+		if (p->flags & PF_FROZEN) {
+			p->flags &= ~PF_FROZEN;
+			wake_up_process(p);
+		} else
+			printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
+	} while_each_thread(g, p);
+
+	read_unlock(&tasklist_lock);
+	schedule();
+	printk( " done\n" );
+}
+
+EXPORT_SYMBOL(refrigerator);