staging: usbip: bugfix prevent driver unbind
Implemented pre_reset and post_reset methods of the driver to prevent the driver from being unbound upon a device reset. Because of this also the asynchronous reset introduced to prevent a race condition is no longer necessary (and sometimes causes problems, because it comes later then expected). Signed-off-by: Arjan Mels <arjan.mels@gmx.net> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net> Cc: Max Vozeler <max@vozeler.com> Cc: usbip-devel <usbip-devel@lists.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -26,6 +26,8 @@
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static int stub_probe(struct usb_interface *interface,
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const struct usb_device_id *id);
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static void stub_disconnect(struct usb_interface *interface);
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static int stub_pre_reset(struct usb_interface *interface);
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static int stub_post_reset(struct usb_interface *interface);
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/*
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* Define device IDs here if you want to explicitly limit exportable devices.
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@ -59,6 +61,8 @@ struct usb_driver stub_driver = {
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.probe = stub_probe,
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.disconnect = stub_disconnect,
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.id_table = stub_table,
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.pre_reset = stub_pre_reset,
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.post_reset = stub_post_reset,
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};
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/*
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@ -541,3 +545,20 @@ static void stub_disconnect(struct usb_interface *interface)
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del_match_busid((char *)udev_busid);
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}
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}
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/*
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* Presence of pre_reset and post_reset prevents the driver from being unbound
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* when the device is being reset
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*/
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int stub_pre_reset(struct usb_interface *interface)
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{
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dev_dbg(&interface->dev, "pre_reset\n");
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return 0;
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}
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int stub_post_reset(struct usb_interface *interface)
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{
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dev_dbg(&interface->dev, "post_reset\n");
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return 0;
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}
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@ -175,16 +175,18 @@ static int tweak_reset_device_cmd(struct urb *urb)
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dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
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/*
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* usb_lock_device_for_reset caused a deadlock: it causes the driver
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* to unbind. In the shutdown the rx thread is signalled to shut down
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* but this thread is pending in the usb_lock_device_for_reset.
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*
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* Instead queue the reset.
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*
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* Unfortunatly an existing usbip connection will be dropped due to
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* driver unbinding.
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* With the implementation of pre_reset and post_reset the driver no
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* longer unbinds. This allows the use of synchronous reset.
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*/
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usb_queue_reset_device(sdev->interface);
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if (usb_lock_device_for_reset(sdev->udev, sdev->interface)<0)
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{
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dev_err(&urb->dev->dev, "could not obtain lock to reset device\n");
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return 0;
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}
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usb_reset_device(sdev->udev);
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usb_unlock_device(sdev->udev);
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return 0;
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}
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