[PATCH 3.19.y-ckt 48/86] usb: xhci: lock mutex on xhci_stop

[Kamal Mostafa]

3.19.8-ckt9 -stable review patch.  If anyone has any objections, please let me know.

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

From: Roger Quadros <rogerq at ti.com>

commit 85ac90f8953a58f6a057b727bc9db97721e3fb8e upstream.

Else it races with xhci_setup_device

Signed-off-by: Roger Quadros <rogerq at ti.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f2194a0..0c4ea93 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -686,8 +686,11 @@ void xhci_stop(struct usb_hcd *hcd)
 	u32 temp;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
+	mutex_lock(&xhci->mutex);
+
 	if (!usb_hcd_is_primary_hcd(hcd)) {
 		xhci_only_stop_hcd(xhci->shared_hcd);
+		mutex_unlock(&xhci->mutex);
 		return;
 	}
 
@@ -726,6 +729,7 @@ void xhci_stop(struct usb_hcd *hcd)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"xhci_stop completed - status = %x",
 			readl(&xhci->op_regs->status));
+	mutex_unlock(&xhci->mutex);
 }
 
 /*
-- 
1.9.1