From: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx>
commit de288e36fe33f7e06fa272bc8e2f85aa386d99aa upstream.
In the case of bounced ep0 requests, we must delay DMA operation until
after ->complete() otherwise we might overwrite contents of req->buf.
This caused problems with RNDIS gadget.
Cc: <stable@xxxxxxxxxxxxxxx> # v4.4 v4.9
Fixes: d62145929992 ("usb: dwc3: gadget: always unmap EP0 requests")
Signed-off-by: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
---
this should apply cleanly to today's v4.4-stable. Thanks
drivers/usb/dwc3/gadget.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 210ff64857e1..ec7a50f98f57 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -235,6 +235,7 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
int status)
{
struct dwc3 *dwc = dep->dwc;
+ unsigned int unmap_after_complete = false;
int i;
if (req->queued) {
@@ -259,11 +260,19 @@ 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 <= 1)
+ /*
+ * NOTICE we don't want to unmap before calling ->complete() if we're
+ * dealing with a bounced ep0 request. If we unmap it here, we would end
+ * up overwritting the contents of req->buf and this could confuse the
+ * gadget driver.
+ */
+ if (dwc->ep0_bounced && dep->number <= 1) {
dwc->ep0_bounced = false;
-
- usb_gadget_unmap_request(&dwc->gadget, &req->request,
- req->direction);
+ unmap_after_complete = true;
+ } else {
+ usb_gadget_unmap_request(&dwc->gadget,
+ &req->request, req->direction);
+ }
dev_dbg(dwc->dev, "request %p from %s completed %d/%d ===> %d\n",
req, dep->name, req->request.actual,
@@ -273,6 +282,10 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
spin_unlock(&dwc->lock);
usb_gadget_giveback_request(&dep->endpoint, &req->request);
spin_lock(&dwc->lock);
+
+ if (unmap_after_complete)
+ usb_gadget_unmap_request(&dwc->gadget,
+ &req->request, req->direction);
}
int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned cmd, u32 param)
--
2.11.0.295.gd7dffce1ce