X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Ffreezer.c;h=bd1d42b17cb2f52f5156506ba25d75376102af7f;hb=c0614829c16ab9d31f1b7d40516decfbf3d32102;hp=cb0931f893061bb5d2b04678ac925dcc498a2f15;hpb=8174f1503f4bf7e9a14b3fbbfdb30c6be6e29f77;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/freezer.c b/kernel/freezer.c
index cb0931f..bd1d42b 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -44,12 +44,19 @@ void refrigerator(void)
 	recalc_sigpending(); /* We sent fake signal, clean it up */
 	spin_unlock_irq(&current->sighand->siglock);
 
+	/* prevent accounting of that task to load */
+	current->flags |= PF_FREEZING;
+
 	for (;;) {
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		if (!frozen(current))
 			break;
 		schedule();
 	}
+
+	/* Remove the accounting blocker */
+	current->flags &= ~PF_FREEZING;
+
 	pr_debug("%s left refrigerator\n", current->comm);
 	__set_current_state(save);
 }
@@ -120,3 +127,35 @@ void cancel_freezing(struct task_struct *p)
 		spin_unlock_irqrestore(&p->sighand->siglock, flags);
 	}
 }
+
+static int __thaw_process(struct task_struct *p)
+{
+	if (frozen(p)) {
+		p->flags &= ~PF_FROZEN;
+		return 1;
+	}
+	clear_freeze_flag(p);
+	return 0;
+}
+
+/*
+ * Wake up a frozen process
+ *
+ * task_lock() is needed to prevent the race with refrigerator() which may
+ * occur if the freezing of tasks fails.  Namely, without the lock, if the
+ * freezing of tasks failed, thaw_tasks() might have run before a task in
+ * refrigerator() could call frozen_process(), in which case the task would be
+ * frozen and no one would thaw it.
+ */
+int thaw_process(struct task_struct *p)
+{
+	task_lock(p);
+	if (__thaw_process(p) == 1) {
+		task_unlock(p);
+		wake_up_process(p);
+		return 1;
+	}
+	task_unlock(p);
+	return 0;
+}
+EXPORT_SYMBOL(thaw_process);