[PATCH v2] sched_ext: Choose the right sch->ops.name to output in the print_scx_info()

[Zqiang]

The print_scx_info() always output scx_root structure's->ops.name,
but for built with CONFIG_EXT_SUB_SCHED=y kernels, the tasks may be
attach an sub scx_sched structure. this commit therefore use the
scx_task_sched_rcu() to correctly get scx_sched structure to output
ops.name, and drop state check.

Suggested-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxx>
---
 kernel/sched/ext.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 2472231ec556..551bfb99157d 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -7680,14 +7680,18 @@ static void kick_cpus_irq_workfn(struct irq_work *irq_work)
  */
 void print_scx_info(const char *log_lvl, struct task_struct *p)
 {
-	struct scx_sched *sch = scx_root;
+	struct scx_sched *sch;
 	enum scx_enable_state state = scx_enable_state();
 	const char *all = READ_ONCE(scx_switching_all) ? "+all" : "";
 	char runnable_at_buf[22] = "?";
 	struct sched_class *class;
 	unsigned long runnable_at;
 
-	if (state == SCX_DISABLED)
+	guard(rcu)();
+
+	sch = scx_task_sched_rcu(p);
+
+	if (!sch)
 		return;
 
 	/*
-- 
2.17.1