Hi Felipe,
On 13/03/17 16:38, Felipe Balbi wrote:
> From: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx>
>
> 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>
> ---
Sekhar found out that this fixes RNDIS for us on v4.9.
Could you please tag this for stable? Thanks.
cheers,
-roger
> 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 0d75158e43fe..79e7a3480d51 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -171,6 +171,7 @@ 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;
>
> req->started = false;
> list_del(&req->list);
> @@ -180,11 +181,19 @@ 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_by_dev(dwc->sysdev,
> - &req->request, req->direction);
> + unmap_after_complete = true;
> + } else {
> + usb_gadget_unmap_request_by_dev(dwc->sysdev,
> + &req->request, req->direction);
> + }
>
> trace_dwc3_gadget_giveback(req);
>
> @@ -192,6 +201,10 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
> usb_gadget_giveback_request(&dep->endpoint, &req->request);
> spin_lock(&dwc->lock);
>
> + if (unmap_after_complete)
> + usb_gadget_unmap_request_by_dev(dwc->sysdev,
> + &req->request, req->direction);
> +
> if (dep->number > 1)
> pm_runtime_put(dwc->dev);
> }
>
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