netdev - [PATCH net 1/2] net/smc: hold conns_lock before calling smc_lgr_register

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Message-Id: <20190626154750.46127-2-ubraun@linux.ibm.com>
Date:   Wed, 26 Jun 2019 17:47:49 +0200
From:   Ursula Braun <ubraun@...ux.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        gor@...ux.ibm.com, heiko.carstens@...ibm.com, raspl@...ux.ibm.com,
        kgraul@...ux.ibm.com, ubraun@...ux.ibm.com, zhp@...il.nju.edu.cn,
        yuehaibing@...wei.com
Subject: [PATCH net 1/2] net/smc: hold conns_lock before calling smc_lgr_register_conn()

From: Huaping Zhou <zhp@...il.nju.edu.cn>

After smc_lgr_create(), the newly created link group is added
to smc_lgr_list, thus is accessible from other context.
Although link group creation is serialized by
smc_create_lgr_pending, the new link group may still be accessed
concurrently. For example, if ib_device is no longer active,
smc_ib_port_event_work() will call smc_port_terminate(), which
in turn will call __smc_lgr_terminate() on every link group of
this device. So conns_lock is required here.

Signed-off-by: Huaping Zhou <zhp@...il.nju.edu.cn>
Signed-off-by: Ursula Braun <ubraun@...ux.ibm.com>
---
 net/smc/smc_core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 2d2850adc2a3..4ca50ddf8d16 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -652,7 +652,10 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
 		rc = smc_lgr_create(smc, ini);
 		if (rc)
 			goto out;
+		lgr = conn->lgr;
+		write_lock_bh(&lgr->conns_lock);
 		smc_lgr_register_conn(conn); /* add smc conn to lgr */
+		write_unlock_bh(&lgr->conns_lock);
 	}
 	conn->local_tx_ctrl.common.type = SMC_CDC_MSG_TYPE;
 	conn->local_tx_ctrl.len = SMC_WR_TX_SIZE;
-- 
2.17.1