sched/deadline: Implement cancel_dl_timer() to use in switched_from_dl()

[firefly-linux-kernel-4.4.55.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0cd34e68680cab320080babdf1d5723f8fef4cdf..379cb87da69df36798a38bb66551a97acf091dbb 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1008,6 +1008,9 @@ inline int task_curr(const struct task_struct *p)
        return cpu_curr(task_cpu(p)) == p;
 }
 
+/*
+ * Can drop rq->lock because from sched_class::switched_from() methods drop it.
+ */
 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
                                       const struct sched_class *prev_class,
                                       int oldprio)
@@ -1015,6 +1018,7 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p,
        if (prev_class != p->sched_class) {
                if (prev_class->switched_from)
                        prev_class->switched_from(rq, p);
+               /* Possble rq->lock 'hole'.  */
                p->sched_class->switched_to(rq, p);
        } else if (oldprio != p->prio || dl_task(p))
                p->sched_class->prio_changed(rq, p, oldprio);