From 94d2d84bcafa3f491c55583154fd543a9b62f836 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Thu, 5 Mar 2020 13:24:01 -0800
Subject: [PATCH] usb: dwc3: gadget: Wrap around when skip TRBs

commit 2dedea035ae82c5af0595637a6eda4655532b21e upstream.

When skipping TRBs, we need to account for wrapping around the ring
buffer and not modifying some invalid TRBs. Without this fix, dwc3 won't
be able to check for available TRBs.

Cc: stable <stable@vger.kernel.org>
Fixes: 7746a8dfb3f9 ("usb: dwc3: gadget: extract dwc3_gadget_ep_skip_trbs()")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/dwc3/gadget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6ac02ba5e4a1..09d6b11246c9 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1518,7 +1518,7 @@ static void dwc3_gadget_ep_skip_trbs(struct dwc3_ep *dep, struct dwc3_request *r
 	for (i = 0; i < req->num_trbs; i++) {
 		struct dwc3_trb *trb;
 
-		trb = req->trb + i;
+		trb = &dep->trb_pool[dep->trb_dequeue];
 		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
 		dwc3_ep_inc_deq(dep);
 	}