[PATCH RFC 1/8] vsock: expose the core port allocator to transports

[Sergio Lopez]

The core port allocator is currently private to connection-oriented
sockets. Virtio datagrams need the same bound-socket lookup tables and
port allocation, while VMCI datagrams must keep their own endpoint
creation and port namespace.

Export vsock_bind_common() with the bound-table locking inside the
helper, and use it for stream and SEQPACKET binds. Keep datagram binds
delegated to the transport so a transport can opt into the core
allocator without changing other transports' binding behavior.

Signed-off-by: Sergio Lopez <slp@xxxxxxxxxx>
---
 include/net/af_vsock.h   |  1 +
 net/vmw_vsock/af_vsock.c | 31 ++++++++++++++++++++++---------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index e8481f12312e..19bd9c1c3e5b 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -220,6 +220,7 @@ void vsock_remove_pending(struct sock *listener, struct sock *pending);
 void vsock_enqueue_accept(struct sock *listener, struct sock *connected);
 void vsock_pending_to_accept(struct sock *listener, struct sock *pending);
 void vsock_insert_connected(struct vsock_sock *vsk);
+int vsock_bind_common(struct vsock_sock *vsk, struct sockaddr_vm *addr);
 void vsock_remove_bound(struct vsock_sock *vsk);
 void vsock_remove_connected(struct vsock_sock *vsk);
 struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index d0508887a2fb..5d1d85e5f519 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -832,8 +832,8 @@ static void vsock_pending_work(struct work_struct *work)
 
 /**** SOCKET OPERATIONS ****/
 
-static int __vsock_bind_connectible(struct vsock_sock *vsk,
-				    struct sockaddr_vm *addr)
+static int __vsock_bind_common(struct vsock_sock *vsk,
+			       struct sockaddr_vm *addr)
 {
 	struct net *net = sock_net(sk_vsock(vsk));
 	struct sockaddr_vm new_addr;
@@ -888,11 +888,26 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 	return 0;
 }
 
-static int __vsock_bind_dgram(struct vsock_sock *vsk,
-			      struct sockaddr_vm *addr)
+/**
+ * vsock_bind_common - bind a socket using the core port allocator
+ * @vsk: socket to bind
+ * @addr: local address to bind to
+ *
+ * The caller must hold the socket lock.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int vsock_bind_common(struct vsock_sock *vsk, struct sockaddr_vm *addr)
 {
-	return vsk->transport->dgram_bind(vsk, addr);
+	int ret;
+
+	spin_lock_bh(&vsock_table_lock);
+	ret = __vsock_bind_common(vsk, addr);
+	spin_unlock_bh(&vsock_table_lock);
+
+	return ret;
 }
+EXPORT_SYMBOL_GPL(vsock_bind_common);
 
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
 {
@@ -914,13 +929,11 @@ static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
 	switch (sk->sk_socket->type) {
 	case SOCK_STREAM:
 	case SOCK_SEQPACKET:
-		spin_lock_bh(&vsock_table_lock);
-		retval = __vsock_bind_connectible(vsk, addr);
-		spin_unlock_bh(&vsock_table_lock);
+		retval = vsock_bind_common(vsk, addr);
 		break;
 
 	case SOCK_DGRAM:
-		retval = __vsock_bind_dgram(vsk, addr);
+		retval = vsk->transport->dgram_bind(vsk, addr);
 		break;
 
 	default:

-- 
2.56.0