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-rw-r--r--kernel/power/process.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/kernel/power/process.c b/kernel/power/process.c
new file mode 100644
index 0000000..78d92dc
--- /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);
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