linux-kernel - [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase

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Date:   Sat, 14 Jan 2017 16:40:39 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     balbi@...nel.org, gregkh@...uxfoundation.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        linaro-kernel@...ts.linaro.org, broonie@...nel.org,
        baolin.wang@...aro.org
Subject: [PATCH] usb: dwc3: ep0: Fix the possible missed request for handling delay STATUS phase

When handing the SETUP packet by composite_setup(), we will release the
dwc->lock. If we get the 'USB_GADGET_DELAYED_STATUS' result from setup
function, which means we need to delay handling the STATUS phase.

But during the lock release period, maybe the request for handling delay
STATUS phase has been queued into list before we set 'dwc->delayed_status'
flag or entering 'EP0_STATUS_PHASE' phase, then we will miss the chance
to handle the STATUS phase. Thus we should check if the request for delay
STATUS phase has been enqueued when entering 'EP0_STATUS_PHASE' phase in
dwc3_ep0_xfernotready(), if so, we should handle it.

Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
---
 drivers/usb/dwc3/ep0.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 9bb1f85..e689ced 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -1123,7 +1123,21 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 		dwc->ep0state = EP0_STATUS_PHASE;

 		if (dwc->delayed_status) {
+			struct dwc3_ep *dep = dwc->eps[0];
+
 			WARN_ON_ONCE(event->endpoint_number != 1);
+			/*
+			 * We should handle the delay STATUS phase here if the
+			 * request for handling delay STATUS has been queued
+			 * into the list.
+			 */
+			if (!list_empty(&dep->pending_list)) {
+				dwc->delayed_status = false;
+				usb_gadget_set_state(&dwc->gadget,
+						     USB_STATE_CONFIGURED);
+				dwc3_ep0_do_control_status(dwc, event);
+			}
+
 			return;
 		}

-- 
1.7.9.5