FAILED: patch "[PATCH] usb: dwc3: gadget: always unmap EP0 requests" failed to apply to 4.9-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From d62145929992f331fdde924d5963ab49588ccc7d Mon Sep 17 00:00:00 2001
From: Felipe Balbi <felipe.balbi@linux.intel.com>
Date: Tue, 20 Dec 2016 14:14:40 +0200
Subject: [PATCH] usb: dwc3: gadget: always unmap EP0 requests

commit 0416e494ce7d ("usb: dwc3: ep0: correct cache
sync issue in case of ep0_bounced") introduced a bug
where we would leak DMA resources which would cause
us to starve the system of them resulting in failing
DMA transfers.

Fix the bug by making sure that we always unmap EP0
requests since those are *always* mapped.

Fixes: 0416e494ce7d ("usb: dwc3: ep0: correct cache
	sync issue in case of ep0_bounced")
Cc: <stable@vger.kernel.org>
Tested-by: Tomasz Medrek <tomaszx.medrek@intel.com>
Reported-by: Janusz Dziedzic <januszx.dziedzic@linux.intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index efddaf5d11d1..0286e3141864 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -180,11 +180,11 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 	if (req->request.status == -EINPROGRESS)
 		req->request.status = status;
 
-	if (dwc->ep0_bounced && dep->number == 0)
+	if (dwc->ep0_bounced && dep->number <= 1)
 		dwc->ep0_bounced = false;
-	else
-		usb_gadget_unmap_request_by_dev(dwc->sysdev,
-				&req->request, req->direction);
+
+	usb_gadget_unmap_request_by_dev(dwc->sysdev,
+			&req->request, req->direction);
 
 	trace_dwc3_gadget_giveback(req);