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From:   "Joel Fernandes (Google)" <joel@joelfernandes.org>
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, rushikesh.s.kadam@intel.com,
        urezki@gmail.com, neeraj.iitr10@gmail.com, frederic@kernel.org,
        paulmck@kernel.org, rostedt@goodmis.org, youssefesmat@google.com,
        surenb@google.com,
        "Joel Fernandes (Google)" <joel@joelfernandes.org>
Subject: [PATCH v8 12/13] rxrpc: Use call_rcu_flush() instead of call_rcu()
Date:   Tue, 11 Oct 2022 18:01:41 +0000
Message-Id: <20221011180142.2742289-13-joel@joelfernandes.org>
In-Reply-To: <20221011180142.2742289-1-joel@joelfernandes.org>
References: <20221011180142.2742289-1-joel@joelfernandes.org>
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call_rcu() changes to save power may cause slowness. Use the
call_rcu_flush() API instead which reverts to the old behavior.

We find this via inspection that the RCU callback does a wakeup of a
thread. This usually indicates that something is waiting on it. To be
safe, let us use call_rcu_flush() here instead.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 net/rxrpc/conn_object.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 22089e37e97f..fdcfb509cc44 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -253,7 +253,7 @@ void rxrpc_kill_connection(struct rxrpc_connection *conn)
 	 * must carry a ref on the connection to prevent us getting here whilst
 	 * it is queued or running.
 	 */
-	call_rcu(&conn->rcu, rxrpc_destroy_connection);
+	call_rcu_flush(&conn->rcu, rxrpc_destroy_connection);
 }
 
 /*
-- 
2.38.0.rc1.362.ged0d419d3c-goog