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-rw-r--r--kernel/time/ntp.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index af8d1d4f3d55..d6132cde9ba3 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -10,6 +10,7 @@
#include <linux/workqueue.h>
#include <linux/hrtimer.h>
#include <linux/jiffies.h>
+#include <linux/kthread.h>
#include <linux/math64.h>
#include <linux/timex.h>
#include <linux/time.h>
@@ -517,10 +518,49 @@ static void sync_cmos_clock(struct work_struct *work)
schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next));
}
+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * RT can not call schedule_delayed_work from real interrupt context.
+ * Need to make a thread to do the real work.
+ */
+static struct task_struct *cmos_delay_thread;
+static bool do_cmos_delay;
+
+static int run_cmos_delay(void *ignore)
+{
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (do_cmos_delay) {
+ do_cmos_delay = false;
+ schedule_delayed_work(&sync_cmos_work, 0);
+ }
+ schedule();
+ }
+ __set_current_state(TASK_RUNNING);
+ return 0;
+}
+
+void ntp_notify_cmos_timer(void)
+{
+ do_cmos_delay = true;
+ /* Make visible before waking up process */
+ smp_wmb();
+ wake_up_process(cmos_delay_thread);
+}
+
+static __init int create_cmos_delay_thread(void)
+{
+ cmos_delay_thread = kthread_run(run_cmos_delay, NULL, "kcmosdelayd");
+ BUG_ON(!cmos_delay_thread);
+ return 0;
+}
+early_initcall(create_cmos_delay_thread);
+#else
void ntp_notify_cmos_timer(void)
{
schedule_delayed_work(&sync_cmos_work, 0);
}
+#endif /* CONFIG_PREEMPT_RT_FULL */
#else
void ntp_notify_cmos_timer(void) { }