From ccb13fe7d9d5a1d2a92ec16fd4d7b5521aaf67d4 Mon Sep 17 00:00:00 2001
From: Alfred Chen <cchalpha@gmail.com>
Date: Thu, 2 Sep 2021 16:19:32 +0000
Subject: [PATCH] sched/alt: Fix for v5.14-prjc-r0 fails on x86 UP build

Mainline add some sched-core related api which cause below fails on x86
UP build, #30.
---
 kernel/sched/alt_core.c  | 24 ++++++++++++++++++++++++
 kernel/sched/alt_sched.h | 30 ++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
index 5df1157a597cb9..bdff1c65e2e9d8 100644
--- a/kernel/sched/alt_core.c
+++ b/kernel/sched/alt_core.c
@@ -492,6 +492,30 @@ rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
 	raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
 }
 
+void raw_spin_rq_lock_nested(struct rq *rq, int subclass)
+{
+	raw_spinlock_t *lock;
+
+	/* Matches synchronize_rcu() in __sched_core_enable() */
+	preempt_disable();
+
+	for (;;) {
+		lock = __rq_lockp(rq);
+		raw_spin_lock_nested(lock, subclass);
+		if (likely(lock == __rq_lockp(rq))) {
+			/* preempt_count *MUST* be > 1 */
+			preempt_enable_no_resched();
+			return;
+		}
+		raw_spin_unlock(lock);
+	}
+}
+
+void raw_spin_rq_unlock(struct rq *rq)
+{
+	raw_spin_unlock(rq_lockp(rq));
+}
+
 /*
  * RQ-clock updating methods:
  */
diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
index 7a48809550bf5a..f03af9ab9123cd 100644
--- a/kernel/sched/alt_sched.h
+++ b/kernel/sched/alt_sched.h
@@ -443,6 +443,36 @@ this_rq_lock_irq(struct rq_flags *rf)
 	return rq;
 }
 
+extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
+extern void raw_spin_rq_unlock(struct rq *rq);
+
+static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
+{
+	return &rq->lock;
+}
+
+static inline raw_spinlock_t *rq_lockp(struct rq *rq)
+{
+	return __rq_lockp(rq);
+}
+
+static inline void raw_spin_rq_lock(struct rq *rq)
+{
+	raw_spin_rq_lock_nested(rq, 0);
+}
+
+static inline void raw_spin_rq_lock_irq(struct rq *rq)
+{
+	local_irq_disable();
+	raw_spin_rq_lock(rq);
+}
+
+static inline void raw_spin_rq_unlock_irq(struct rq *rq)
+{
+	raw_spin_rq_unlock(rq);
+	local_irq_enable();
+}
+
 static inline int task_current(struct rq *rq, struct task_struct *p)
 {
 	return rq->curr == p;