LITMUS^RT core: add should_wait_for_stack() callback

Allow plugins to give up when waiting for a stack to become available.

1 files changed, 13 insertions, 0 deletions

diff --git a/kernel/sched/litmus.c b/kernel/sched/litmus.c
index 2cdba907f0a8..4fa5a941a284 100644
--- a/kernel/sched/litmus.c
+++ b/kernel/sched/litmus.c
@@ -78,6 +78,19 @@ litmus_schedule(struct rq *rq, struct task_struct *prev)
                         if (next->rt_param.stack_in_use == NO_CPU)
                                 TRACE_TASK(next,"descheduled. Proceeding.\n");
 
+                        if (!litmus->should_wait_for_stack(next)) {
+                                /* plugin aborted the wait */
+                                TRACE_TASK(next,
+                                           "plugin gave up waiting for stack\n");
+                                next = NULL;
+                                /* Make sure plugin is given a chance to
+                                 * reconsider. */
+                                litmus_reschedule_local();
+                                /* give up */
+                                raw_spin_lock(&rq->lock);
+                                return next;
+                        }
+
                         if (lt_before(_maybe_deadlock + 1000000000L,
                                       litmus_clock())) {
                                 /* We've been spinning for 1s.