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Subject[13/71] staging: usbip: bugfixes related to kthread conversion
2.6.33-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Arjan Mels <arjan.mels@gmx.net>

commit d2dd0b07c3e725d386d20294ec906f7ddef207fa upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/staging/usbip/stub_rx.c | 40 +++++++++++++++-------------------------
1 file changed, 15 insertions(+), 25 deletions(-)

--- a/drivers/staging/usbip/stub_rx.c
+++ b/drivers/staging/usbip/stub_rx.c
@@ -168,33 +168,23 @@ static int tweak_set_configuration_cmd(s

static int tweak_reset_device_cmd(struct urb *urb)
{
- struct usb_ctrlrequest *req;
- __u16 value;
- __u16 index;
- int ret;
+ struct stub_priv *priv = (struct stub_priv *) urb->context;
+ struct stub_device *sdev = priv->sdev;

- req = (struct usb_ctrlrequest *) urb->setup_packet;
- value = le16_to_cpu(req->wValue);
- index = le16_to_cpu(req->wIndex);
+ usbip_uinfo("reset_device %s\n", dev_name(&urb->dev->dev));

- usbip_uinfo("reset_device (port %d) to %s\n", index,
- dev_name(&urb->dev->dev));
-
- /* 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");
-
- 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;
}

/*



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