From: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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. Signed-off-by: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx> Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- 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 f4a36f4669bb..b1b833843b9a 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -221,6 +221,7 @@ 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) { @@ -245,11 +246,19 @@ 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, @@ -258,6 +267,10 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req, spin_unlock(&dwc->lock); req->request.complete(&dep->endpoint, &req->request); spin_lock(&dwc->lock); + + if (unmap_after_complete) + usb_gadget_unmap_request(&dwc->gadget, + &req->request, req->direction); } static const char *dwc3_gadget_ep_cmd_string(u8 cmd) -- 2.12.2