xHCI: cancel command after command timeout

commit 6e4468b9a0793dfb53eb80d9fe52c739b13b27fd upstream.

The patch is used to cancel command when the command isn't
acknowledged and a timeout occurs.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu <elricfu1@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Miroslav Sabljic <miroslav.sabljic@avl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 6456a56..5361fd8 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1252,6 +1252,9 @@
 	union xhci_trb		*last_trb;
 };
 
+/* xHCI command default timeout value */
+#define XHCI_CMD_DEFAULT_TIMEOUT	(5 * HZ)
+
 /* command descriptor */
 struct xhci_cd {
 	struct list_head	cancel_cmd_list;