--- /dev/null
+From 55168470835688e5da5828cdcf1b1498d7baadb1 Mon Sep 17 00:00:00 2001
+From: Felipe Balbi <felipe.balbi@linux.intel.com>
+Date: Mon, 11 Sep 2017 10:45:12 +0300
+Subject: usb: dwc3: ep0: fix DMA starvation by assigning req->trb on ep0
+
+From: Felipe Balbi <felipe.balbi@linux.intel.com>
+
+commit 55168470835688e5da5828cdcf1b1498d7baadb1 upstream.
+
+If we don't assign a TRB to ep0 requests, we won't be able to unmap
+the request later on resulting in starvation of DMA resources.
+
+Fixes: 4a71fcb8ac5f ("usb: dwc3: gadget: only unmap requests from DMA if mapped")
+Reported-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
+Tested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
+Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/usb/dwc3/ep0.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/drivers/usb/dwc3/ep0.c
++++ b/drivers/usb/dwc3/ep0.c
+@@ -990,6 +990,8 @@ static void __dwc3_ep0_do_control_data(s
+ DWC3_TRBCTL_CONTROL_DATA,
+ true);
+
++ req->trb = &dwc->ep0_trb[dep->trb_enqueue - 1];
++
+ /* Now prepare one extra TRB to align transfer size */
+ dwc3_ep0_prepare_one_trb(dep, dwc->bounce_addr,
+ maxpacket - rem,
+@@ -1015,6 +1017,8 @@ static void __dwc3_ep0_do_control_data(s
+ DWC3_TRBCTL_CONTROL_DATA,
+ true);
+
++ req->trb = &dwc->ep0_trb[dep->trb_enqueue - 1];
++
+ /* Now prepare one extra TRB to align transfer size */
+ dwc3_ep0_prepare_one_trb(dep, dwc->bounce_addr,
+ 0, DWC3_TRBCTL_CONTROL_DATA,
+@@ -1029,6 +1033,9 @@ static void __dwc3_ep0_do_control_data(s
+ dwc3_ep0_prepare_one_trb(dep, req->request.dma,
+ req->request.length, DWC3_TRBCTL_CONTROL_DATA,
+ false);
++
++ req->trb = &dwc->ep0_trb[dep->trb_enqueue];
++
+ ret = dwc3_ep0_start_trans(dep);
+ }
+