linux-kernel - [PATCH v2] rcu-tasks: Remove unnecessary smp_store_release() in cblist_init

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Message-ID: <20260105011951.72850-1-qiang.zhang@linux.dev>
Date: Mon,  5 Jan 2026 09:19:51 +0800
From: Zqiang <qiang.zhang@...ux.dev>
To: paulmck@...nel.org,
	frederic@...nel.org,
	neeraj.upadhyay@...nel.org,
	joelagnelf@...dia.com,
	boqun.feng@...il.com,
	urezki@...il.com
Cc: qiang.zhang@...ux.dev,
	rcu@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] rcu-tasks: Remove unnecessary smp_store_release() in cblist_init_generic()

The cblist_init_generic() is executed during the CPU early boot
phase due to commit:30ef09635b9e ("rcu-tasks: Initialize callback
lists at rcu_init() time"), at this time, only one boot CPU is
online and the irq is disabled. this commit therefore use routine
assignment replace of smp_store_release() and WRITE_ONCE() in the
cblist_init_generic().

Signed-off-by: Zqiang <qiang.zhang@...ux.dev>
---
 kernel/rcu/tasks.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 76f952196a29..c736900317cd 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -290,9 +290,9 @@ static void cblist_init_generic(struct rcu_tasks *rtp)
 	shift = ilog2(rcu_task_cpu_ids / lim);
 	if (((rcu_task_cpu_ids - 1) >> shift) >= lim)
 		shift++;
-	WRITE_ONCE(rtp->percpu_enqueue_shift, shift);
-	WRITE_ONCE(rtp->percpu_dequeue_lim, lim);
-	smp_store_release(&rtp->percpu_enqueue_lim, lim);
+	rtp->percpu_enqueue_shift = shift;
+	rtp->percpu_dequeue_lim = lim;
+	rtp->percpu_enqueue_lim = lim;
 
 	pr_info("%s: Setting shift to %d and lim to %d rcu_task_cb_adjust=%d rcu_task_cpu_ids=%d.\n",
 			rtp->name, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim),
-- 
2.48.1