[RFC PATCH 04/13] vsock: add 'transport' member in the struct vsock_sock

[Stefano Garzarella <sgarzare@redhat.com>]

As a preparation to support multiple transports, this patch adds
the 'transport' member at the 'struct vsock_sock'.
This new field is initialized during the creation in the
__vsock_create() function.

This patch also renames the global 'transport' pointer to
'transport_single', since for now we're only supporting a single
transport registered at run-time.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 include/net/af_vsock.h   |  1 +
 net/vmw_vsock/af_vsock.c | 56 +++++++++++++++++++++++++++-------------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index c660402b10f2..a5e1e134261d 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -27,6 +27,7 @@ extern spinlock_t vsock_table_lock;
 struct vsock_sock {
 	/* sk must be the first member. */
 	struct sock sk;
+	const struct vsock_transport *transport;
 	struct sockaddr_vm local_addr;
 	struct sockaddr_vm remote_addr;
 	/* Links for the global tables of bound and connected sockets. */
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index f609434b2794..81ee2561c76f 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -126,7 +126,7 @@ static struct proto vsock_proto = {
  */
 #define VSOCK_DEFAULT_CONNECT_TIMEOUT (2 * HZ)
 
-static const struct vsock_transport *transport;
+static const struct vsock_transport *transport_single;
 static DEFINE_MUTEX(vsock_register_mutex);
 
 /**** UTILS ****/
@@ -408,7 +408,9 @@ static bool vsock_is_pending(struct sock *sk)
 
 static int vsock_send_shutdown(struct sock *sk, int mode)
 {
-	return transport->shutdown(vsock_sk(sk), mode);
+	struct vsock_sock *vsk = vsock_sk(sk);
+
+	return vsk->transport->shutdown(vsk, mode);
 }
 
 static void vsock_pending_work(struct work_struct *work)
@@ -518,7 +520,7 @@ static int __vsock_bind_stream(struct vsock_sock *vsk,
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {
-	return transport->dgram_bind(vsk, addr);
+	return vsk->transport->dgram_bind(vsk, addr);
 }
 
 static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
@@ -536,7 +538,7 @@ static int __vsock_bind(struct sock *sk, struct sockaddr_vm *addr)
 	 * like AF_INET prevents binding to a non-local IP address (in most
 	 * cases), we only allow binding to the local CID.
 	 */
-	cid = transport->get_local_cid();
+	cid = vsk->transport->get_local_cid();
 	if (addr->svm_cid != cid && addr->svm_cid != VMADDR_CID_ANY)
 		return -EADDRNOTAVAIL;
 
@@ -586,6 +588,7 @@ struct sock *__vsock_create(struct net *net,
 		sk->sk_type = type;
 
 	vsk = vsock_sk(sk);
+	vsk->transport = transport_single;
 	vsock_addr_init(&vsk->local_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
 	vsock_addr_init(&vsk->remote_addr, VMADDR_CID_ANY, VMADDR_PORT_ANY);
 
@@ -616,7 +619,7 @@ struct sock *__vsock_create(struct net *net,
 		vsk->connect_timeout = VSOCK_DEFAULT_CONNECT_TIMEOUT;
 	}
 
-	if (transport->init(vsk, psk) < 0) {
+	if (vsk->transport->init(vsk, psk) < 0) {
 		sk_free(sk);
 		return NULL;
 	}
@@ -638,7 +641,7 @@ static void __vsock_release(struct sock *sk)
 		vsk = vsock_sk(sk);
 		pending = NULL;	/* Compiler warning. */
 
-		transport->release(vsk);
+		vsk->transport->release(vsk);
 
 		lock_sock(sk);
 		sock_orphan(sk);
@@ -662,7 +665,7 @@ static void vsock_sk_destruct(struct sock *sk)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);
 
-	transport->destruct(vsk);
+	vsk->transport->destruct(vsk);
 
 	/* When clearing these addresses, there's no need to set the family and
 	 * possibly register the address family with the kernel.
@@ -686,13 +689,13 @@ static int vsock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 s64 vsock_stream_has_data(struct vsock_sock *vsk)
 {
-	return transport->stream_has_data(vsk);
+	return vsk->transport->stream_has_data(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_data);
 
 s64 vsock_stream_has_space(struct vsock_sock *vsk)
 {
-	return transport->stream_has_space(vsk);
+	return vsk->transport->stream_has_space(vsk);
 }
 EXPORT_SYMBOL_GPL(vsock_stream_has_space);
 
@@ -861,6 +864,7 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
 			mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
 
 	} else if (sock->type == SOCK_STREAM) {
+		const struct vsock_transport *transport = vsk->transport;
 		lock_sock(sk);
 
 		/* Listening sockets that have connections in their accept
@@ -936,6 +940,7 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 	struct sock *sk;
 	struct vsock_sock *vsk;
 	struct sockaddr_vm *remote_addr;
+	const struct vsock_transport *transport;
 
 	if (msg->msg_flags & MSG_OOB)
 		return -EOPNOTSUPP;
@@ -944,6 +949,7 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 	err = 0;
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 
 	lock_sock(sk);
 
@@ -1028,8 +1034,8 @@ static int vsock_dgram_connect(struct socket *sock,
 	if (err)
 		goto out;
 
-	if (!transport->dgram_allow(remote_addr->svm_cid,
-				    remote_addr->svm_port)) {
+	if (!vsk->transport->dgram_allow(remote_addr->svm_cid,
+					 remote_addr->svm_port)) {
 		err = -EINVAL;
 		goto out;
 	}
@@ -1045,7 +1051,9 @@ static int vsock_dgram_connect(struct socket *sock,
 static int vsock_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 			       size_t len, int flags)
 {
-	return transport->dgram_dequeue(vsock_sk(sock->sk), msg, len, flags);
+	struct vsock_sock *vsk = vsock_sk(sock->sk);
+
+	return vsk->transport->dgram_dequeue(vsk, msg, len, flags);
 }
 
 static const struct proto_ops vsock_dgram_ops = {
@@ -1071,6 +1079,8 @@ static const struct proto_ops vsock_dgram_ops = {
 
 static int vsock_transport_cancel_pkt(struct vsock_sock *vsk)
 {
+	const struct vsock_transport *transport = vsk->transport;
+
 	if (!transport->cancel_pkt)
 		return -EOPNOTSUPP;
 
@@ -1107,6 +1117,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
 	int err;
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	const struct vsock_transport *transport;
 	struct sockaddr_vm *remote_addr;
 	long timeout;
 	DEFINE_WAIT(wait);
@@ -1114,6 +1125,7 @@ static int vsock_stream_connect(struct socket *sock, struct sockaddr *addr,
 	err = 0;
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 
 	lock_sock(sk);
 
@@ -1357,6 +1369,7 @@ static int vsock_stream_setsockopt(struct socket *sock,
 	int err;
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	const struct vsock_transport *transport;
 	u64 val;
 
 	if (level != AF_VSOCK)
@@ -1377,6 +1390,7 @@ static int vsock_stream_setsockopt(struct socket *sock,
 	err = 0;
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 
 	lock_sock(sk);
 
@@ -1434,6 +1448,7 @@ static int vsock_stream_getsockopt(struct socket *sock,
 	int len;
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	const struct vsock_transport *transport;
 	u64 val;
 
 	if (level != AF_VSOCK)
@@ -1457,6 +1472,7 @@ static int vsock_stream_getsockopt(struct socket *sock,
 	err = 0;
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 
 	switch (optname) {
 	case SO_VM_SOCKETS_BUFFER_SIZE:
@@ -1501,6 +1517,7 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 {
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	const struct vsock_transport *transport;
 	ssize_t total_written;
 	long timeout;
 	int err;
@@ -1509,6 +1526,7 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 	total_written = 0;
 	err = 0;
 
@@ -1640,6 +1658,7 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 {
 	struct sock *sk;
 	struct vsock_sock *vsk;
+	const struct vsock_transport *transport;
 	int err;
 	size_t target;
 	ssize_t copied;
@@ -1650,6 +1669,7 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 
 	sk = sock->sk;
 	vsk = vsock_sk(sk);
+	transport = vsk->transport;
 	err = 0;
 
 	lock_sock(sk);
@@ -1864,7 +1884,7 @@ static long vsock_dev_do_ioctl(struct file *filp,
 
 	switch (cmd) {
 	case IOCTL_VM_SOCKETS_GET_LOCAL_CID:
-		if (put_user(transport->get_local_cid(), p) != 0)
+		if (put_user(transport_single->get_local_cid(), p) != 0)
 			retval = -EFAULT;
 		break;
 
@@ -1911,7 +1931,7 @@ int __vsock_core_init(const struct vsock_transport *t, struct module *owner)
 	if (err)
 		return err;
 
-	if (transport) {
+	if (transport_single) {
 		err = -EBUSY;
 		goto err_busy;
 	}
@@ -1920,7 +1940,7 @@ int __vsock_core_init(const struct vsock_transport *t, struct module *owner)
 	 * unload while there are open sockets.
 	 */
 	vsock_proto.owner = owner;
-	transport = t;
+	transport_single = t;
 
 	vsock_device.minor = MISC_DYNAMIC_MINOR;
 	err = misc_register(&vsock_device);
@@ -1950,7 +1970,7 @@ int __vsock_core_init(const struct vsock_transport *t, struct module *owner)
 err_deregister_misc:
 	misc_deregister(&vsock_device);
 err_reset_transport:
-	transport = NULL;
+	transport_single = NULL;
 err_busy:
 	mutex_unlock(&vsock_register_mutex);
 	return err;
@@ -1967,7 +1987,7 @@ void vsock_core_exit(void)
 
 	/* We do not want the assignment below re-ordered. */
 	mb();
-	transport = NULL;
+	transport_single = NULL;
 
 	mutex_unlock(&vsock_register_mutex);
 }
@@ -1978,7 +1998,7 @@ const struct vsock_transport *vsock_core_get_transport(void)
 	/* vsock_register_mutex not taken since only the transport uses this
 	 * function and only while registered.
 	 */
-	return transport;
+	return transport_single;
 }
 EXPORT_SYMBOL_GPL(vsock_core_get_transport);
 
-- 
2.21.0