tcp: expose __tcp_sock_set_cork and __tcp_sock_set_nodelay

Expose __tcp_sock_set_cork() and __tcp_sock_set_nodelay() for use in
MPTCP setsockopt code -- namely for syncing MPTCP socket options with
subflows inside sync_socket_options() while already holding the subflow
socket lock.
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Maxim Galaganov <max@internet.ru>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/tcp.h

@@ -512,11 +512,13 @@ static inline u16 tcp_mss_clamp(const struct tcp_sock *tp, u16 mss)
 int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
 		  int shiftlen);
 
+void __tcp_sock_set_cork(struct sock *sk, bool on);
 void tcp_sock_set_cork(struct sock *sk, bool on);
 int tcp_sock_set_keepcnt(struct sock *sk, int val);
 int tcp_sock_set_keepidle_locked(struct sock *sk, int val);
 int tcp_sock_set_keepidle(struct sock *sk, int val);
 int tcp_sock_set_keepintvl(struct sock *sk, int val);
+void __tcp_sock_set_nodelay(struct sock *sk, bool on);
 void tcp_sock_set_nodelay(struct sock *sk);
 void tcp_sock_set_quickack(struct sock *sk, int val);
 int tcp_sock_set_syncnt(struct sock *sk, int val);

net/ipv4/tcp.c

@@ -3207,7 +3207,7 @@ static void tcp_enable_tx_delay(void)
  * TCP_CORK can be set together with TCP_NODELAY and it is stronger than
  * TCP_NODELAY.
  */
-static void __tcp_sock_set_cork(struct sock *sk, bool on)
+void __tcp_sock_set_cork(struct sock *sk, bool on)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 
@@ -3235,7 +3235,7 @@ EXPORT_SYMBOL(tcp_sock_set_cork);
  * However, when TCP_NODELAY is set we make an explicit push, which overrides
  * even TCP_CORK for currently queued segments.
  */
-static void __tcp_sock_set_nodelay(struct sock *sk, bool on)
+void __tcp_sock_set_nodelay(struct sock *sk, bool on)
 {
 	if (on) {
 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;