Use guards to reduce gotos and simplify control flow.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/sched/core.c | 73 ++++++++++++++++++++++------------------------------
1 file changed, 32 insertions(+), 41 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8799,55 +8799,46 @@ int __sched yield_to(struct task_struct
{
struct task_struct *curr = current;
struct rq *rq, *p_rq;
- unsigned long flags;
int yielded = 0;
- local_irq_save(flags);
- rq = this_rq();
+ scoped_guard (irqsave) {
+ rq = this_rq();
again:
- p_rq = task_rq(p);
- /*
- * If we're the only runnable task on the rq and target rq also
- * has only one task, there's absolutely no point in yielding.
- */
- if (rq->nr_running == 1 && p_rq->nr_running == 1) {
- yielded = -ESRCH;
- goto out_irq;
- }
-
- double_rq_lock(rq, p_rq);
- if (task_rq(p) != p_rq) {
- double_rq_unlock(rq, p_rq);
- goto again;
- }
-
- if (!curr->sched_class->yield_to_task)
- goto out_unlock;
-
- if (curr->sched_class != p->sched_class)
- goto out_unlock;
-
- if (task_on_cpu(p_rq, p) || !task_is_running(p))
- goto out_unlock;
-
- yielded = curr->sched_class->yield_to_task(rq, p);
- if (yielded) {
- schedstat_inc(rq->yld_count);
+ p_rq = task_rq(p);
/*
- * Make p's CPU reschedule; pick_next_entity takes care of
- * fairness.
+ * If we're the only runnable task on the rq and target rq also
+ * has only one task, there's absolutely no point in yielding.
*/
- if (preempt && rq != p_rq)
- resched_curr(p_rq);
- }
+ if (rq->nr_running == 1 && p_rq->nr_running == 1)
+ return -ESRCH;
-out_unlock:
- double_rq_unlock(rq, p_rq);
-out_irq:
- local_irq_restore(flags);
+ guard(double_rq_lock)(rq, p_rq);
+ if (task_rq(p) != p_rq)
+ goto again;
+
+ if (!curr->sched_class->yield_to_task)
+ return 0;
+
+ if (curr->sched_class != p->sched_class)
+ return 0;
+
+ if (task_on_cpu(p_rq, p) || !task_is_running(p))
+ return 0;
+
+ yielded = curr->sched_class->yield_to_task(rq, p);
+ if (yielded) {
+ schedstat_inc(rq->yld_count);
+ /*
+ * Make p's CPU reschedule; pick_next_entity
+ * takes care of fairness.
+ */
+ if (preempt && rq != p_rq)
+ resched_curr(p_rq);
+ }
+ }
- if (yielded > 0)
+ if (yielded)
schedule();
return yielded;
