rds: tcp: 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: 5413d1ba ("net: do not block BH while processing socket backlog")
Fixes: d41a69f1 ("tcp: make tcp_sendmsg() aware of socket backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/tcp_connect.c

@@ -43,7 +43,7 @@ void rds_tcp_state_change(struct sock *sk)
 	struct rds_connection *conn;
 	struct rds_tcp_connection *tc;
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	conn = sk->sk_user_data;
 	if (!conn) {
 		state_change = sk->sk_state_change;
@@ -69,7 +69,7 @@ void rds_tcp_state_change(struct sock *sk)
 			break;
 	}
 out:
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 	state_change(sk);
 }
 

net/rds/tcp_listen.c

@@ -166,7 +166,7 @@ void rds_tcp_listen_data_ready(struct sock *sk)
 
 	rdsdebug("listen data ready sk %p\n", sk);
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	ready = sk->sk_user_data;
 	if (!ready) { /* check for teardown race */
 		ready = sk->sk_data_ready;
@@ -183,7 +183,7 @@ void rds_tcp_listen_data_ready(struct sock *sk)
 		rds_tcp_accept_work(sk);
 
 out:
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 	ready(sk);
 }
 

net/rds/tcp_recv.c

@@ -301,7 +301,7 @@ void rds_tcp_data_ready(struct sock *sk)
 
 	rdsdebug("data ready sk %p\n", sk);
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	conn = sk->sk_user_data;
 	if (!conn) { /* check for teardown race */
 		ready = sk->sk_data_ready;
@@ -315,7 +315,7 @@ void rds_tcp_data_ready(struct sock *sk)
 	if (rds_tcp_read_sock(conn, GFP_ATOMIC) == -ENOMEM)
 		queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
 out:
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 	ready(sk);
 }
 

net/rds/tcp_send.c

@@ -180,7 +180,7 @@ void rds_tcp_write_space(struct sock *sk)
 	struct rds_connection *conn;
 	struct rds_tcp_connection *tc;
 
-	read_lock(&sk->sk_callback_lock);
+	read_lock_bh(&sk->sk_callback_lock);
 	conn = sk->sk_user_data;
 	if (!conn) {
 		write_space = sk->sk_write_space;
@@ -200,7 +200,7 @@ void rds_tcp_write_space(struct sock *sk)
 		queue_delayed_work(rds_wq, &conn->c_send_w, 0);
 
 out:
-	read_unlock(&sk->sk_callback_lock);
+	read_unlock_bh(&sk->sk_callback_lock);
 
 	/*
 	 * write_space is only called when data leaves tcp's send queue if