tcp: export do_tcp_sendpages and tcp_rate_check_app_limited functions

Export do_tcp_sendpages and tcp_rate_check_app_limited, since tls will need to
sendpages while the socket is already locked.

tcp_sendpage is exported, but requires the socket lock to not be held already.
Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -350,6 +350,8 @@ int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw);
 int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
 int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size,
 		 int flags);
+ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
+		 size_t size, int flags);
 void tcp_release_cb(struct sock *sk);
 void tcp_wfree(struct sk_buff *skb);
 void tcp_write_timer_handler(struct sock *sk);

net/ipv4/tcp.c

@@ -901,7 +901,7 @@ static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
 	return mss_now;
 }
 
-static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
+ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 			 size_t size, int flags)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
@@ -1032,6 +1032,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 	}
 	return sk_stream_error(sk, flags, err);
 }
+EXPORT_SYMBOL_GPL(do_tcp_sendpages);
 
 int tcp_sendpage(struct sock *sk, struct page *page, int offset,
 		 size_t size, int flags)

net/ipv4/tcp_rate.c

@@ -185,3 +185,4 @@ void tcp_rate_check_app_limited(struct sock *sk)
 		tp->app_limited =
 			(tp->delivered + tcp_packets_in_flight(tp)) ? : 1;
 }
+EXPORT_SYMBOL_GPL(tcp_rate_check_app_limited);