tcp/dccp: add inet_csk_reqsk_queue_drop_and_put() helper

Let's reduce the confusion about inet_csk_reqsk_queue_drop() :
In many cases we also need to release reference on request socket,
so add a helper to do this, reducing code size and complexity.

Fixes: 4bdc3d66147b ("tcp/dccp: fix behavior of stale SYN_RECV request sockets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index ba9ec9a..b85c720 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -546,6 +546,13 @@
 }
 EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);
 
+void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req)
+{
+	inet_csk_reqsk_queue_drop(sk, req);
+	reqsk_put(req);
+}
+EXPORT_SYMBOL(inet_csk_reqsk_queue_drop_and_put);
+
 static void reqsk_timer_handler(unsigned long data)
 {
 	struct request_sock *req = (struct request_sock *)data;
@@ -608,8 +615,7 @@
 		return;
 	}
 drop:
-	inet_csk_reqsk_queue_drop(sk_listener, req);
-	reqsk_put(req);
+	inet_csk_reqsk_queue_drop_and_put(sk_listener, req);
 }
 
 static void reqsk_queue_hash_req(struct request_sock *req,