[PATCH 1/2] sched_ext: Rename scx_reenq_wait_dispatching() to scx_wait_dispatching()

[Kuba Piecuch]

Waiting for SCX_OPSS_DISPATCHING to clear isn't specific to the reenqueue
paths. Any path which takes a task off a DSQ can find it while the
dispatch is still in flight, and the next patch calls the helper from the
DSQ consume and move paths. Rename it to scx_wait_dispatching() and
update its comment accordingly.

No functional change.

Assisted-by: Claude:claude-opus-5.5
Signed-off-by: Kuba Piecuch <jpiecuch@xxxxxxxxxx>
---
 kernel/sched/ext/ext.c      | 13 +++++++------
 kernel/sched/ext/internal.h |  2 +-
 kernel/sched/ext/sub.c      |  2 +-
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index a6a72ae7f815..acfeadf5503d 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -4483,11 +4483,12 @@ static bool local_task_should_reenq(struct rq *rq, struct task_struct *p,
 }
 
 /*
- * The dispatcher stores the final ops_state after dropping the DSQ lock, so @p
- * can be found on a DSQ while still %SCX_OPSS_DISPATCHING. Reenqueueing @p
- * before that store lands would have it clobber the new %SCX_OPSS_QUEUED.
+ * The dispatcher runs ops.dequeue() and stores the final ops_state after
+ * dropping the DSQ lock, so @p can be found on a DSQ while still
+ * %SCX_OPSS_DISPATCHING. Wait for the dispatch to finish before operating on
+ * @p.
  */
-void scx_reenq_wait_dispatching(struct task_struct *p)
+void scx_wait_dispatching(struct task_struct *p)
 {
 	if (unlikely(atomic_long_read_acquire(&p->scx.ops_state) == SCX_OPSS_DISPATCHING))
 		wait_ops_state(p, SCX_OPSS_DISPATCHING);
@@ -4536,7 +4537,7 @@ static u32 reenq_local(struct scx_sched *sch, struct rq *rq, u64 reenq_flags)
 		if (!local_task_should_reenq(rq, p, &reenq_flags, &reason))
 			continue;
 
-		scx_reenq_wait_dispatching(p);
+		scx_wait_dispatching(p);
 		scx_dispatch_dequeue(rq, p);
 
 		if (WARN_ON_ONCE(p->scx.flags & SCX_TASK_REENQ_REASON_MASK))
@@ -4660,7 +4661,7 @@ static void reenq_user(struct rq *rq, struct scx_dispatch_q *dsq, u64 reenq_flag
 		}
 
 		/* @p is on @dsq, its rq and @dsq are locked */
-		scx_reenq_wait_dispatching(p);
+		scx_wait_dispatching(p);
 		dispatch_dequeue_locked(p, dsq);
 		raw_spin_unlock(&dsq->lock);
 
diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h
index 85579fcabf52..352547aedbb7 100644
--- a/kernel/sched/ext/internal.h
+++ b/kernel/sched/ext/internal.h
@@ -2123,7 +2123,7 @@ void scx_kick_cpu(struct scx_sched *sch, s32 cpu, u64 flags);
 u64 __scx_bpf_now(struct rq *rq);
 void schedule_dsq_reenq(struct scx_sched *sch, struct scx_dispatch_q *dsq,
 			u64 reenq_flags, struct rq *locked_rq);
-void scx_reenq_wait_dispatching(struct task_struct *p);
+void scx_wait_dispatching(struct task_struct *p);
 int __scx_init_task(struct scx_sched *sch, struct task_struct *p,
 		    struct cgroup *cgrp, bool fork);
 void scx_enable_task(struct scx_sched *sch, struct task_struct *p);
diff --git a/kernel/sched/ext/sub.c b/kernel/sched/ext/sub.c
index c9b44ab3bd0a..fee75fcdb59d 100644
--- a/kernel/sched/ext/sub.c
+++ b/kernel/sched/ext/sub.c
@@ -797,7 +797,7 @@ void scx_reenq_reject(struct rq *rq)
 		if (WARN_ON_ONCE(p->migration_pending))
 			continue;
 
-		scx_reenq_wait_dispatching(p);
+		scx_wait_dispatching(p);
 		scx_dispatch_dequeue(rq, p);
 
 		if (WARN_ON_ONCE(p->scx.flags & SCX_TASK_REENQ_REASON_MASK))
-- 
2.56.0.385.gd3acb90ef8-goog