tcp: small changes in reqsk_put() and reqsk_free()

In reqsk_free(), use DEBUG_NET_WARN_ON_ONCE()
instead of WARN_ON_ONCE() for a condition which never fired.

In reqsk_put() directly call __reqsk_free(), there is no
point checking rsk_refcnt again right after a transition to zero.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/net/request_sock.h

@@ -172,14 +172,14 @@ static inline void __reqsk_free(struct request_sock *req)
 
 static inline void reqsk_free(struct request_sock *req)
 {
-	WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0);
+	DEBUG_NET_WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0);
 	__reqsk_free(req);
 }
 
 static inline void reqsk_put(struct request_sock *req)
 {
 	if (refcount_dec_and_test(&req->rsk_refcnt))
-		reqsk_free(req);
+		__reqsk_free(req);
 }
 
 /*