These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / kernel / sched / swait.c

diff --git a/kernel/kernel/sched/swait.c b/kernel/kernel/sched/swait.c
new file mode 100644 (file)
index 0000000..205fe36
--- /dev/null
+++ b/kernel/kernel/sched/swait.c
@@ -0,0 +1,143 @@
+#include <linux/sched.h>
+#include <linux/swait.h>
+#include <linux/suspend.h>
+
+void __init_swait_queue_head(struct swait_queue_head *q, const char *name,
+                            struct lock_class_key *key)
+{
+       raw_spin_lock_init(&q->lock);
+       lockdep_set_class_and_name(&q->lock, key, name);
+       INIT_LIST_HEAD(&q->task_list);
+}
+EXPORT_SYMBOL(__init_swait_queue_head);
+
+/*
+ * The thing about the wake_up_state() return value; I think we can ignore it.
+ *
+ * If for some reason it would return 0, that means the previously waiting
+ * task is already running, so it will observe condition true (or has already).
+ */
+void swake_up_locked(struct swait_queue_head *q)
+{
+       struct swait_queue *curr;
+
+       if (list_empty(&q->task_list))
+               return;
+
+       curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
+       wake_up_process(curr->task);
+       list_del_init(&curr->task_list);
+}
+EXPORT_SYMBOL(swake_up_locked);
+
+void swake_up_all_locked(struct swait_queue_head *q)
+{
+       struct swait_queue *curr;
+       int wakes = 0;
+
+       while (!list_empty(&q->task_list)) {
+
+               curr = list_first_entry(&q->task_list, typeof(*curr),
+                                       task_list);
+               wake_up_process(curr->task);
+               list_del_init(&curr->task_list);
+               wakes++;
+       }
+       if (pm_in_action)
+               return;
+       WARN(wakes > 2, "complate_all() with %d waiters\n", wakes);
+}
+EXPORT_SYMBOL(swake_up_all_locked);
+
+void swake_up(struct swait_queue_head *q)
+{
+       unsigned long flags;
+
+       if (!swait_active(q))
+               return;
+
+       raw_spin_lock_irqsave(&q->lock, flags);
+       swake_up_locked(q);
+       raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(swake_up);
+
+/*
+ * Does not allow usage from IRQ disabled, since we must be able to
+ * release IRQs to guarantee bounded hold time.
+ */
+void swake_up_all(struct swait_queue_head *q)
+{
+       struct swait_queue *curr;
+       LIST_HEAD(tmp);
+
+       if (!swait_active(q))
+               return;
+
+       raw_spin_lock_irq(&q->lock);
+       list_splice_init(&q->task_list, &tmp);
+       while (!list_empty(&tmp)) {
+               curr = list_first_entry(&tmp, typeof(*curr), task_list);
+
+               wake_up_state(curr->task, TASK_NORMAL);
+               list_del_init(&curr->task_list);
+
+               if (list_empty(&tmp))
+                       break;
+
+               raw_spin_unlock_irq(&q->lock);
+               raw_spin_lock_irq(&q->lock);
+       }
+       raw_spin_unlock_irq(&q->lock);
+}
+EXPORT_SYMBOL(swake_up_all);
+
+void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+       wait->task = current;
+       if (list_empty(&wait->task_list))
+               list_add(&wait->task_list, &q->task_list);
+}
+
+void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+       unsigned long flags;
+
+       raw_spin_lock_irqsave(&q->lock, flags);
+       __prepare_to_swait(q, wait);
+       set_current_state(state);
+       raw_spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(prepare_to_swait);
+
+long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state)
+{
+       if (signal_pending_state(state, current))
+               return -ERESTARTSYS;
+
+       prepare_to_swait(q, wait, state);
+
+       return 0;
+}
+EXPORT_SYMBOL(prepare_to_swait_event);
+
+void __finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+       __set_current_state(TASK_RUNNING);
+       if (!list_empty(&wait->task_list))
+               list_del_init(&wait->task_list);
+}
+
+void finish_swait(struct swait_queue_head *q, struct swait_queue *wait)
+{
+       unsigned long flags;
+
+       __set_current_state(TASK_RUNNING);
+
+       if (!list_empty_careful(&wait->task_list)) {
+               raw_spin_lock_irqsave(&q->lock, flags);
+               list_del_init(&wait->task_list);
+               raw_spin_unlock_irqrestore(&q->lock, flags);
+       }
+}
+EXPORT_SYMBOL(finish_swait);