staging: usbip: bugfixes related to kthread conversion

When doing a usb port reset do a queued reset instead to prevent a
deadlock: the reset will cause the driver to unbind, causing the
usb_driver_lock_for_reset to stall.

Signed-off-by: Arjan Mels <arjan.mels@gmx.net>
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Cc: Max Vozeler <max@vozeler.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 25 deletions

diff --git a/drivers/staging/usbip/stub_rx.c b/drivers/staging/usbip/stub_rx.c
index 6445f12cb4fd..51fbd0986475 100644
--- a/drivers/staging/usbip/stub_rx.c
+++ b/drivers/staging/usbip/stub_rx.c
@@ -171,33 +171,23 @@ static int tweak_set_configuration_cmd(struct urb *urb)
 
 static int tweak_reset_device_cmd(struct urb *urb)
 {
-        struct usb_ctrlrequest *req;
-        __u16 value;
-        __u16 index;
-        int ret;
-
-        req = (struct usb_ctrlrequest *) urb->setup_packet;
-        value = le16_to_cpu(req->wValue);
-        index = le16_to_cpu(req->wIndex);
-
-        usbip_uinfo("reset_device (port %d) to %s\n", index,
-                                                dev_name(&urb->dev->dev));
+        struct stub_priv *priv = (struct stub_priv *) urb->context;
+        struct stub_device *sdev = priv->sdev;
 
-        /* all interfaces should be owned by usbip driver, so just reset it.  */
-        ret = usb_lock_device_for_reset(urb->dev, NULL);
-        if (ret < 0) {
-                dev_err(&urb->dev->dev, "lock for reset\n");
-                return ret;
-        }
-
-        /* try to reset the device */
-        ret = usb_reset_device(urb->dev);
-        if (ret < 0)
-                dev_err(&urb->dev->dev, "device reset\n");
+        usbip_uinfo("reset_device %s\n", dev_name(&urb->dev->dev));
 
-        usb_unlock_device(urb->dev);
-
-        return ret;
+        /*
+         * usb_lock_device_for_reset caused a deadlock: it causes the driver
+         * to unbind. In the shutdown the rx thread is signalled to shut down
+         * but this thread is pending in the usb_lock_device_for_reset.
+         *
+         * Instead queue the reset.
+         *
+         * Unfortunatly an existing usbip connection will be dropped due to
+         * driver unbinding.
+         */
+        usb_queue_reset_device(sdev->interface);
+        return 0;
 }
 
 /*