um: virtio: Remove device on disconnect

If the connection drops, just remove the device, we don't try
to recover from this right now.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/virtio_uml.c

@@ -42,6 +42,13 @@
 #define to_virtio_uml_device(_vdev) \
 	container_of(_vdev, struct virtio_uml_device, vdev)
 
+struct virtio_uml_platform_data {
+	u32 virtio_device_id;
+	const char *socket_path;
+	struct work_struct conn_broken_wk;
+	struct platform_device *pdev;
+};
+
 struct virtio_uml_device {
 	struct virtio_device vdev;
 	struct platform_device *pdev;
@@ -50,6 +57,7 @@ struct virtio_uml_device {
 	u64 features;
 	u64 protocol_features;
 	u8 status;
+	u8 registered:1;
 };
 
 struct virtio_uml_vq_info {
@@ -107,12 +115,21 @@ static int vhost_user_recv_header(int fd, struct vhost_user_msg *msg)
 	return full_read(fd, msg, sizeof(msg->header));
 }
 
-static int vhost_user_recv(int fd, struct vhost_user_msg *msg,
+static int vhost_user_recv(struct virtio_uml_device *vu_dev,
+			   int fd, struct vhost_user_msg *msg,
 			   size_t max_payload_size)
 {
 	size_t size;
 	int rc = vhost_user_recv_header(fd, msg);
 
+	if (rc == -ECONNRESET && vu_dev->registered) {
+		struct virtio_uml_platform_data *pdata;
+
+		pdata = vu_dev->pdev->dev.platform_data;
+
+		virtio_break_device(&vu_dev->vdev);
+		schedule_work(&pdata->conn_broken_wk);
+	}
 	if (rc)
 		return rc;
 	size = msg->header.size;
@@ -125,7 +142,7 @@ static int vhost_user_recv_resp(struct virtio_uml_device *vu_dev,
 				struct vhost_user_msg *msg,
 				size_t max_payload_size)
 {
-	int rc = vhost_user_recv(vu_dev->sock, msg, max_payload_size);
+	int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg, max_payload_size);
 
 	if (rc)
 		return rc;
@@ -155,7 +172,7 @@ static int vhost_user_recv_req(struct virtio_uml_device *vu_dev,
 			       struct vhost_user_msg *msg,
 			       size_t max_payload_size)
 {
-	int rc = vhost_user_recv(vu_dev->req_fd, msg, max_payload_size);
+	int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg, max_payload_size);
 
 	if (rc)
 		return rc;
@@ -963,11 +980,6 @@ static void virtio_uml_release_dev(struct device *d)
 
 /* Platform device */
 
-struct virtio_uml_platform_data {
-	u32 virtio_device_id;
-	const char *socket_path;
-};
-
 static int virtio_uml_probe(struct platform_device *pdev)
 {
 	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
@@ -1005,6 +1017,7 @@ static int virtio_uml_probe(struct platform_device *pdev)
 	rc = register_virtio_device(&vu_dev->vdev);
 	if (rc)
 		put_device(&vu_dev->vdev.dev);
+	vu_dev->registered = 1;
 	return rc;
 
 error_init:
@@ -1034,13 +1047,31 @@ static struct device vu_cmdline_parent = {
 static bool vu_cmdline_parent_registered;
 static int vu_cmdline_id;
 
+static int vu_unregister_cmdline_device(struct device *dev, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
+
+	kfree(pdata->socket_path);
+	platform_device_unregister(pdev);
+	return 0;
+}
+
+static void vu_conn_broken(struct work_struct *wk)
+{
+	struct virtio_uml_platform_data *pdata;
+
+	pdata = container_of(wk, struct virtio_uml_platform_data, conn_broken_wk);
+	vu_unregister_cmdline_device(&pdata->pdev->dev, NULL);
+}
+
 static int vu_cmdline_set(const char *device, const struct kernel_param *kp)
 {
 	const char *ids = strchr(device, ':');
 	unsigned int virtio_device_id;
 	int processed, consumed, err;
 	char *socket_path;
-	struct virtio_uml_platform_data pdata;
+	struct virtio_uml_platform_data pdata, *ppdata;
 	struct platform_device *pdev;
 
 	if (!ids || ids == device)
@@ -1079,6 +1110,11 @@ static int vu_cmdline_set(const char *device, const struct kernel_param *kp)
 	err = PTR_ERR_OR_ZERO(pdev);
 	if (err)
 		goto free;
+
+	ppdata = pdev->dev.platform_data;
+	ppdata->pdev = pdev;
+	INIT_WORK(&ppdata->conn_broken_wk, vu_conn_broken);
+
 	return 0;
 
 free:
@@ -1121,16 +1157,6 @@ __uml_help(vu_cmdline_param_ops,
 );
 
 
-static int vu_unregister_cmdline_device(struct device *dev, void *data)
-{
-	struct platform_device *pdev = to_platform_device(dev);
-	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
-
-	kfree(pdata->socket_path);
-	platform_device_unregister(pdev);
-	return 0;
-}
-
 static void vu_unregister_cmdline_devices(void)
 {
 	if (vu_cmdline_parent_registered) {