tipc: block BH in TCP callbacks

TCP stack can now run from process context.

Use read_lock_bh(&sk->sk_callback_lock) variant to restore previous
assumption.

Fixes: 5413d1babe8f ("net: do not block BH while processing socket backlog")
Fixes: d41a69f1d390 ("tcp: make tcp_sendmsg() aware of socket backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
Cc: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/server.c

@@ -138,28 +138,28 @@ static void sock_data_ready(struct sock *sk)
 {
 	struct tipc_conn *con;
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	con = sock2con(sk);
 	if (con && test_bit(CF_CONNECTED, &con->flags)) {
 		conn_get(con);
 		if (!queue_work(con->server->rcv_wq, &con->rwork))
 			conn_put(con);
 	}
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 }
 
 static void sock_write_space(struct sock *sk)
 {
 	struct tipc_conn *con;
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	con = sock2con(sk);
 	if (con && test_bit(CF_CONNECTED, &con->flags)) {
 		conn_get(con);
 		if (!queue_work(con->server->send_wq, &con->swork))
 			conn_put(con);
 	}
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 }
 
 static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)