inet: add proper refcounting to request sock

reqsk_put() is the generic function that should be used
to release a refcount (and automatically call reqsk_free())

reqsk_free() might be called if refcount is known to be 0
or undefined.

refcnt is set to one in inet_csk_reqsk_queue_add()

As request socks are not yet in global ehash table,
I added temporary debugging checks in reqsk_put() and reqsk_free()

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 34581f9..3390ba6 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -340,7 +340,7 @@
 out:
 	release_sock(sk);
 	if (req)
-		__reqsk_free(req);
+		reqsk_put(req);
 	return newsk;
 out_err:
 	newsk = NULL;
@@ -635,7 +635,7 @@
 				/* Drop this request */
 				inet_csk_reqsk_queue_unlink(parent, req, reqp);
 				reqsk_queue_removed(queue, req);
-				reqsk_free(req);
+				reqsk_put(req);
 				continue;
 			}
 			reqp = &req->dl_next;
@@ -837,7 +837,7 @@
 		sock_put(child);
 
 		sk_acceptq_removed(sk);
-		__reqsk_free(req);
+		reqsk_put(req);
 	}
 	if (queue->fastopenq != NULL) {
 		/* Free all the reqs queued in rskq_rst_head. */
@@ -847,7 +847,7 @@
 		spin_unlock_bh(&queue->fastopenq->lock);
 		while ((req = acc_req) != NULL) {
 			acc_req = req->dl_next;
-			__reqsk_free(req);
+			reqsk_put(req);
 		}
 	}
 	WARN_ON(sk->sk_ack_backlog);
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index f17db89..5ae0c49 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -219,9 +219,9 @@
 }
 EXPORT_SYMBOL_GPL(__cookie_v4_check);
 
-static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb,
-					   struct request_sock *req,
-					   struct dst_entry *dst)
+static struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb,
+				    struct request_sock *req,
+				    struct dst_entry *dst)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct sock *child;
@@ -357,7 +357,7 @@
 	ireq->opt = tcp_v4_save_options(skb);
 
 	if (security_inet_conn_request(sk, skb, req)) {
-		reqsk_free(req);
+		reqsk_put(req);
 		goto out;
 	}
 
@@ -378,7 +378,7 @@
 	security_req_classify_flow(req, flowi4_to_flowi(&fl4));
 	rt = ip_route_output_key(sock_net(sk), &fl4);
 	if (IS_ERR(rt)) {
-		reqsk_free(req);
+		reqsk_put(req);
 		goto out;
 	}
 
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index fe77417..8438131 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -253,7 +253,7 @@
 		fastopenq->rskq_rst_head = req1->dl_next;
 		fastopenq->qlen--;
 		spin_unlock(&fastopenq->lock);
-		reqsk_free(req1);
+		reqsk_put(req1);
 	}
 	return true;
 }