1 files changed, 121 insertions, 0 deletions

diff --git a/kernel/power/process.c b/kernel/power/process.c
new file mode 100644
index 000000000000..78d92dc6a1ed
--- /dev/null
+++ b/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);