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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 12/14] scsi/scsi_error: Use call_rcu_flush() instead of call_rcu()
Date:   Wed, 19 Oct 2022 15:51:42 -0700
Message-Id: <20221019225144.2500095-12-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>

Slow boot time is seen on KVM running typical Linux distributions due to
SCSI layer calling call_rcu(). Recent changes to save power may be
causing this slowness. Using call_rcu_flush() fixes the issue and brings
the boot time back to what it originally was. Convert it.

Tested-by: Joel Fernandes (Google) <joel@joelfernandes.org>
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>
---
 drivers/scsi/scsi_error.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 6995c89792300..634672e67c81f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -312,7 +312,7 @@ void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
 	 * Ensure that all tasks observe the host state change before the
 	 * host_failed change.
 	 */
-	call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
+	call_rcu_flush(&scmd->rcu, scsi_eh_inc_host_failed);
 }
 
 /**
-- 
2.31.1.189.g2e36527f23