staging: usbip: claim ports used by shared devices

A device should not be able to be used concurrently both by
the server and the client. Claiming the port used by the
shared device ensures no interface drivers bind to it and
that it is not usable from the server.

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/staging/usbip/stub_dev.c b/drivers/staging/usbip/stub_dev.c
index ee899f01c008..952743c752d7 100644
--- a/drivers/staging/usbip/stub_dev.c
+++ b/drivers/staging/usbip/stub_dev.c
@@ -339,6 +339,7 @@ static int stub_probe(struct usb_device *udev)
 	const char *udev_busid = dev_name(&udev->dev);
 	int err = 0;
 	struct bus_id_priv *busid_priv;
+	int rc;
 
 	dev_dbg(&udev->dev, "Enter\n");
 
@@ -388,6 +389,18 @@ static int stub_probe(struct usb_device *udev)
 	busid_priv->sdev = sdev;
 	busid_priv->udev = udev;
 
+	/*
+	 * Claim this hub port.
+	 * It doesn't matter what value we pass as owner
+	 * (struct dev_state) as long as it is unique.
+	 */
+	rc = usb_hub_claim_port(udev->parent, udev->portnum,
+			(struct dev_state *) udev);
+	if (rc) {
+		dev_dbg(&udev->dev, "unable to claim port\n");
+		return rc;
+	}
+
 	err = stub_add_files(&udev->dev);
 	if (err) {
 		dev_err(&udev->dev, "stub_add_files for %s\n", udev_busid);
@@ -424,6 +437,7 @@ static void stub_disconnect(struct usb_device *udev)
 	struct stub_device *sdev;
 	const char *udev_busid = dev_name(&udev->dev);
 	struct bus_id_priv *busid_priv;
+	int rc;
 
 	dev_dbg(&udev->dev, "Enter\n");
 
@@ -448,6 +462,14 @@ static void stub_disconnect(struct usb_device *udev)
 	 */
 	stub_remove_files(&udev->dev);
 
+	/* release port */
+	rc = usb_hub_release_port(udev->parent, udev->portnum,
+				  (struct dev_state *) udev);
+	if (rc) {
+		dev_dbg(&udev->dev, "unable to release port\n");
+		return;
+	}
+
 	/* If usb reset is called from event handler */
 	if (busid_priv->sdev->ud.eh == current)
 		return;