releases/4.1.14/revert-usb-dwc3-gadget-drop-unnecessary-loop-when-cleaning-up-trbs.patch

From d115d7050a0d2c4967532f18c9cb522fea6b7280 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Mon, 31 Aug 2015 19:48:28 +0300
Subject: Revert "usb: dwc3: gadget: drop unnecessary loop when cleaning up TRBs"
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From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>

commit d115d7050a0d2c4967532f18c9cb522fea6b7280 upstream.

This reverts commit 8f2c9544aba636134303105ecb164190a39dece4.

As it breaks g_ether on my Baytrail FFRD8 device. Everything starts out
fine, but after a bit of data has been transferred it just stops
flowing.

Note that I do get a bunch of these "NOHZ: local_softirq_pending 08"
when booting the machine, but I'm not really sure if they're related
to this problem.

Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/dwc3/gadget.c |   37 +++++++++++++++++++++----------------
 1 file changed, 21 insertions(+), 16 deletions(-)

--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1859,27 +1859,32 @@ static int dwc3_cleanup_done_reqs(struct
 	unsigned int		i;
 	int			ret;
 
-	req = next_request(&dep->req_queued);
-	if (!req) {
-		WARN_ON_ONCE(1);
-		return 1;
-	}
-	i = 0;
 	do {
-		slot = req->start_slot + i;
-		if ((slot == DWC3_TRB_NUM - 1) &&
+		req = next_request(&dep->req_queued);
+		if (!req) {
+			WARN_ON_ONCE(1);
+			return 1;
+		}
+		i = 0;
+		do {
+			slot = req->start_slot + i;
+			if ((slot == DWC3_TRB_NUM - 1) &&
 				usb_endpoint_xfer_isoc(dep->endpoint.desc))
-			slot++;
-		slot %= DWC3_TRB_NUM;
-		trb = &dep->trb_pool[slot];
+				slot++;
+			slot %= DWC3_TRB_NUM;
+			trb = &dep->trb_pool[slot];
+
+			ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
+					event, status);
+			if (ret)
+				break;
+		} while (++i < req->request.num_mapped_sgs);
+
+		dwc3_gadget_giveback(dep, req, status);
 
-		ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
-				event, status);
 		if (ret)
 			break;
-	} while (++i < req->request.num_mapped_sgs);
-
-	dwc3_gadget_giveback(dep, req, status);
+	} while (1);
 
 	if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
 			list_empty(&dep->req_queued)) {