usb: wusbcore: fix deadlock in wusbhc_gtk_rekey

When multiple wireless USB devices are connected and one of the devices
disconnects, the host will distribute a new group key to the remaining
devicese using wusbhc_gtk_rekey.  wusbhc_gtk_rekey takes the
wusbhc->mutex and holds it while it submits a URB to set the new key.
This causes a deadlock in wa_urb_enqueue when it calls a device lookup
helper function that takes the same lock.

This patch changes wusbhc_gtk_rekey to submit a work item to set the GTK
so that the URB is submitted without holding wusbhc->mutex.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/wusbcore/wusbhc.h b/drivers/usb/wusbcore/wusbhc.h
index 711b195..6bd3b81 100644
--- a/drivers/usb/wusbcore/wusbhc.h
+++ b/drivers/usb/wusbcore/wusbhc.h
@@ -97,6 +97,7 @@
 	struct kref refcnt;
 	struct wusbhc *wusbhc;
 	struct list_head cack_node;	/* Connect-Ack list */
+	struct list_head rekey_node;	/* GTK rekey list */
 	u8 port_idx;
 	u8 addr;
 	u8 beacon_type:4;
@@ -107,8 +108,6 @@
 	struct usb_wireless_cap_descriptor *wusb_cap_descr;
 	struct uwb_mas_bm availability;
 	struct work_struct devconnect_acked_work;
-	struct urb *set_gtk_urb;
-	struct usb_ctrlrequest *set_gtk_req;
 	struct usb_device *usb_dev;
 };
 
@@ -296,8 +295,7 @@
 	} __attribute__((packed)) gtk;
 	u8 gtk_index;
 	u32 gtk_tkid;
-	struct work_struct gtk_rekey_done_work;
-	int pending_set_gtks;
+	struct work_struct gtk_rekey_work;
 
 	struct usb_encryption_descriptor *ccm1_etd;
 };