[PATCH] nvmet-tcp: fixup hang in nvmet_tcp_listen_data_ready()

[hare at kernel.org]

From: Hannes Reinecke <hare at kernel.org>

When the socket is closed while in TCP_LISTEN a callback is run to
flush all outstanding packets, which in turns calls
nvmet_tcp_listen_data_ready() with the sk_callback_lock held.
So we need to check if we are in TCP_LISTEN before attempting
to get the sk_callback_lock() to avoid a deadlock.

Signed-off-by: Hannes Reinecke <hare at kernel.org>
Tested-by:  Yi Zhang <yi.zhang at redhat.com>
---
 drivers/nvme/target/tcp.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 470bf37e5a63..2e9a3e698b70 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1992,14 +1992,13 @@ static void nvmet_tcp_listen_data_ready(struct sock *sk)
 
 	trace_sk_data_ready(sk);
 
+	if (sk->sk_state != TCP_LISTEN)
+		return;
+
 	read_lock_bh(&sk->sk_callback_lock);
 	port = sk->sk_user_data;
-	if (!port)
-		goto out;
-
-	if (sk->sk_state == TCP_LISTEN)
+	if (port)
 		queue_work(nvmet_wq, &port->accept_work);
-out:
 	read_unlock_bh(&sk->sk_callback_lock);
 }
 
-- 
2.43.0