rt domain: evil hack to avoid recursive hrtimer lock acquisition

This is a really dirty hack, but works for now since our real-time
tasks do not use hrtimer_wakeup().

The need for this will go away when we port since newer versions of the
Linux kernel allow timers to be activated directly in the scheduler.

1 files changed, 21 insertions, 3 deletions

diff --git a/litmus/norqlock.c b/litmus/norqlock.c
index 769240075a..b812f34960 100644
--- a/litmus/norqlock.c
+++ b/litmus/norqlock.c
@@ -8,9 +8,10 @@
 
 struct worklist {
         struct no_rqlock_work* next;
+        int hrtimer_hack;
 };
 
-static DEFINE_PER_CPU(struct worklist, norq_worklist) = {NULL};
+static DEFINE_PER_CPU(struct worklist, norq_worklist) = {NULL, 0};
 
 void init_no_rqlock_work(struct no_rqlock_work* w, work_t work,
                          unsigned long arg)
@@ -33,15 +34,32 @@ void __do_without_rqlock(struct no_rqlock_work *work)
         local_irq_restore(flags);
 }
 
+void hrtimer_wakeup_hack(int onoff)
+{
+        preempt_disable();
+        __get_cpu_var(norq_worklist).hrtimer_hack = onoff;
+        preempt_enable();
+}
+
 void tick_no_rqlock(void)
 {
         long flags;
         struct no_rqlock_work *todo, *next;
+        struct worklist* wl;
+
 
         local_irq_save(flags);
 
-        next = __get_cpu_var(norq_worklist).next;
-        __get_cpu_var(norq_worklist).next = NULL;
+        wl = &__get_cpu_var(norq_worklist); 
+
+        if (wl->hrtimer_hack) {
+                /* bail out! */
+                local_irq_restore(flags);
+                return;
+        }
+
+        next = wl->next;
+        wl->next = NULL;
 
         local_irq_restore(flags);