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From: Stefano Garzarella <sgarzare@redhat.com>
To: netdev@vger.kernel.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	kvm@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Dexuan Cui <decui@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Jorgen Hansen <jhansen@vmware.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	linux-hyperv@vger.kernel.org,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	virtualization@lists.linux-foundation.org
Subject: [PATCH net-next 13/14] vsock: prevent transport modules unloading
Date: Wed, 23 Oct 2019 11:55:53 +0200
Message-ID: <20191023095554.11340-14-sgarzare@redhat.com> (raw)
In-Reply-To: <20191023095554.11340-1-sgarzare@redhat.com>

This patch adds 'module' member in the 'struct vsock_transport'
in order to get/put the transport module. This prevents the
module unloading while sockets are assigned to it.

We increase the module refcnt when a socket is assigned to a
transport, and we decrease the module refcnt when the socket
is destructed.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
RFC -> v1:
- fixed typo 's/tranport/transport/' in a comment (Stefan)
---
 drivers/vhost/vsock.c            |  2 ++
 include/net/af_vsock.h           |  2 ++
 net/vmw_vsock/af_vsock.c         | 20 ++++++++++++++++----
 net/vmw_vsock/hyperv_transport.c |  2 ++
 net/vmw_vsock/virtio_transport.c |  2 ++
 net/vmw_vsock/vmci_transport.c   |  1 +
 6 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index b235f4bbe8ea..fdda9ec625ad 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -386,6 +386,8 @@ static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
 
 static struct virtio_transport vhost_transport = {
 	.transport = {
+		.module                   = THIS_MODULE,
+
 		.get_local_cid            = vhost_transport_get_local_cid,
 
 		.init                     = virtio_transport_do_socket_init,
diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 27a3463e4892..269e2f034789 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -100,6 +100,8 @@ struct vsock_transport_send_notify_data {
 #define VSOCK_TRANSPORT_F_DGRAM		0x00000004
 
 struct vsock_transport {
+	struct module *module;
+
 	/* Initialize/tear-down socket. */
 	int (*init)(struct vsock_sock *, struct vsock_sock *);
 	void (*destruct)(struct vsock_sock *);
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index dddd85d9a147..1f2e707cae66 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -380,6 +380,16 @@ void vsock_enqueue_accept(struct sock *listener, struct sock *connected)
 }
 EXPORT_SYMBOL_GPL(vsock_enqueue_accept);
 
+static void vsock_deassign_transport(struct vsock_sock *vsk)
+{
+	if (!vsk->transport)
+		return;
+
+	vsk->transport->destruct(vsk);
+	module_put(vsk->transport->module);
+	vsk->transport = NULL;
+}
+
 /* Assign a transport to a socket and call the .init transport callback.
  *
  * Note: for stream socket this must be called when vsk->remote_addr is set
@@ -413,10 +423,13 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk)
 			return 0;
 
 		vsk->transport->release(vsk);
-		vsk->transport->destruct(vsk);
+		vsock_deassign_transport(vsk);
 	}
 
-	if (!new_transport)
+	/* We increase the module refcnt to prevent the transport unloading
+	 * while there are open sockets assigned to it.
+	 */
+	if (!new_transport || !try_module_get(new_transport->module))
 		return -ENODEV;
 
 	vsk->transport = new_transport;
@@ -737,8 +750,7 @@ static void vsock_sk_destruct(struct sock *sk)
 {
 	struct vsock_sock *vsk = vsock_sk(sk);
 
-	if (vsk->transport)
-		vsk->transport->destruct(vsk);
+	vsock_deassign_transport(vsk);
 
 	/* When clearing these addresses, there's no need to set the family and
 	 * possibly register the address family with the kernel.
diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index 0ea66d87af39..d0a349d85414 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -857,6 +857,8 @@ int hvs_notify_send_post_enqueue(struct vsock_sock *vsk, ssize_t written,
 }
 
 static struct vsock_transport hvs_transport = {
+	.module                   = THIS_MODULE,
+
 	.get_local_cid            = hvs_get_local_cid,
 
 	.init                     = hvs_sock_init,
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 83ad85050384..1458c5c8b64d 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -462,6 +462,8 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
 
 static struct virtio_transport virtio_transport = {
 	.transport = {
+		.module                   = THIS_MODULE,
+
 		.get_local_cid            = virtio_transport_get_local_cid,
 
 		.init                     = virtio_transport_do_socket_init,
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 04437f822d82..0cbf023fae11 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -2019,6 +2019,7 @@ static u32 vmci_transport_get_local_cid(void)
 }
 
 static struct vsock_transport vmci_transport = {
+	.module = THIS_MODULE,
 	.init = vmci_transport_socket_init,
 	.destruct = vmci_transport_destruct,
 	.release = vmci_transport_release,
-- 
2.21.0


  parent reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23  9:55 [PATCH net-next 00/14] vsock: add multi-transports support Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 01/14] vsock/vmci: remove unused VSOCK_DEFAULT_CONNECT_TIMEOUT Stefano Garzarella
2019-10-30 14:54   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 02/14] vsock: remove vm_sockets_get_local_cid() Stefano Garzarella
2019-10-30 14:55   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 03/14] vsock: remove include/linux/vm_sockets.h file Stefano Garzarella
2019-10-30 14:57   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 04/14] vsock: add 'transport' member in the struct vsock_sock Stefano Garzarella
2019-10-30 14:57   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 05/14] vsock/virtio: add transport parameter to the virtio_transport_reset_no_sock() Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 06/14] vsock: add 'struct vsock_sock *' param to vsock_core_get_transport() Stefano Garzarella
2019-10-30 15:01   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 07/14] vsock: handle buffer_size sockopts in the core Stefano Garzarella
2019-10-27  8:08   ` Stefan Hajnoczi
2019-10-30 15:08   ` Jorgen Hansen
2019-10-31  8:50     ` Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 08/14] vsock: add vsock_create_connected() called by transports Stefano Garzarella
2019-10-27  8:12   ` Stefan Hajnoczi
2019-10-30 15:12   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 09/14] vsock: move vsock_insert_unbound() in the vsock_create() Stefano Garzarella
2019-10-30 15:12   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 10/14] hv_sock: set VMADDR_CID_HOST in the hvs_remote_addr_init() Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 11/14] vsock: add multi-transports support Stefano Garzarella
2019-10-23 15:08   ` Stefano Garzarella
2019-10-30 15:40     ` Jorgen Hansen
2019-10-31  8:54       ` Stefano Garzarella
2019-11-11 13:53   ` Jorgen Hansen
2019-11-11 17:17     ` Stefano Garzarella
2019-11-12  9:59       ` Jorgen Hansen
2019-11-12 10:36         ` Stefano Garzarella
2019-11-13 14:30           ` Jorgen Hansen
2019-11-13 16:38             ` Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 12/14] vsock/vmci: register vmci_transport only when VMCI guest/host are active Stefano Garzarella
2019-10-27  8:17   ` Stefan Hajnoczi
2019-10-29 16:35     ` Stefano Garzarella
2019-11-04 10:10   ` Stefano Garzarella
2019-11-11 16:27   ` Jorgen Hansen
2019-11-11 17:30     ` Stefano Garzarella
2019-11-12 10:03       ` Jorgen Hansen
2019-11-12 10:42         ` Stefano Garzarella
2019-10-23  9:55 ` Stefano Garzarella [this message]
2019-11-11 16:36   ` [PATCH net-next 13/14] vsock: prevent transport modules unloading Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 14/14] vsock: fix bind() behaviour taking care of CID Stefano Garzarella
2019-11-11 16:53   ` Jorgen Hansen
2019-10-27  8:01 ` [PATCH net-next 00/14] vsock: add multi-transports support Stefan Hajnoczi
2019-10-29 16:27   ` Stefano Garzarella

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