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From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, kernel-team@fb.com,
        rostedt@goodmis.org, Uladzislau Rezki <urezki@gmail.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        "Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 13/14] workqueue: Make queue_rcu_work() use call_rcu_flush()
Date:   Wed, 19 Oct 2022 15:51:43 -0700
Message-Id: <20221019225144.2500095-13-paulmck@kernel.org>
In-Reply-To: <20221019225138.GA2499943@paulmck-ThinkPad-P17-Gen-1>
References: <20221019225138.GA2499943@paulmck-ThinkPad-P17-Gen-1>
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From: Uladzislau Rezki <urezki@gmail.com>

call_rcu() changes to save power will slow down RCU workqueue items
queued via queue_rcu_work(). This may not be an issue, however we cannot
assume that workqueue users are OK with long delays. Use
call_rcu_flush() API instead which reverts to the old behavior.

Signed-off-by: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/workqueue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 7cd5f5e7e0a1b..b4b0e828b529e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1771,7 +1771,7 @@ bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
 
 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
 		rwork->wq = wq;
-		call_rcu(&rwork->rcu, rcu_work_rcufn);
+		call_rcu_flush(&rwork->rcu, rcu_work_rcufn);
 		return true;
 	}
 
-- 
2.31.1.189.g2e36527f23